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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2011-12-19 13:23:15 -0500
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2011-12-19 13:23:15 -0500
commit612ef28a045efadb3a98d4492ead7806a146485d (patch)
tree05621c87b37e91c27b06d450d76adffe97ce9666 /kernel/sched
parentc3e0ef9a298e028a82ada28101ccd5cf64d209ee (diff)
parent07cde2608a3b5c66515363f1b53623b1536b9785 (diff)
Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into cputime-tip
Conflicts: drivers/cpufreq/cpufreq_conservative.c drivers/cpufreq/cpufreq_ondemand.c drivers/macintosh/rack-meter.c fs/proc/stat.c fs/proc/uptime.c kernel/sched/core.c
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/Makefile20
-rw-r--r--kernel/sched/auto_group.c258
-rw-r--r--kernel/sched/auto_group.h64
-rw-r--r--kernel/sched/clock.c350
-rw-r--r--kernel/sched/core.c8119
-rw-r--r--kernel/sched/cpupri.c241
-rw-r--r--kernel/sched/cpupri.h34
-rw-r--r--kernel/sched/debug.c510
-rw-r--r--kernel/sched/fair.c5577
-rw-r--r--kernel/sched/features.h70
-rw-r--r--kernel/sched/idle_task.c99
-rw-r--r--kernel/sched/rt.c2048
-rw-r--r--kernel/sched/sched.h1136
-rw-r--r--kernel/sched/stats.c111
-rw-r--r--kernel/sched/stats.h231
-rw-r--r--kernel/sched/stop_task.c108
16 files changed, 18976 insertions, 0 deletions
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
new file mode 100644
index 000000000000..9a7dd35102a3
--- /dev/null
+++ b/kernel/sched/Makefile
@@ -0,0 +1,20 @@
1ifdef CONFIG_FUNCTION_TRACER
2CFLAGS_REMOVE_clock.o = -pg
3endif
4
5ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
6# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
7# needed for x86 only. Why this used to be enabled for all architectures is beyond
8# me. I suspect most platforms don't need this, but until we know that for sure
9# I turn this off for IA-64 only. Andreas Schwab says it's also needed on m68k
10# to get a correct value for the wait-channel (WCHAN in ps). --davidm
11CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
12endif
13
14obj-y += core.o clock.o idle_task.o fair.o rt.o stop_task.o
15obj-$(CONFIG_SMP) += cpupri.o
16obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o
17obj-$(CONFIG_SCHEDSTATS) += stats.o
18obj-$(CONFIG_SCHED_DEBUG) += debug.o
19
20
diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
new file mode 100644
index 000000000000..e8a1f83ee0e7
--- /dev/null
+++ b/kernel/sched/auto_group.c
@@ -0,0 +1,258 @@
1#ifdef CONFIG_SCHED_AUTOGROUP
2
3#include "sched.h"
4
5#include <linux/proc_fs.h>
6#include <linux/seq_file.h>
7#include <linux/kallsyms.h>
8#include <linux/utsname.h>
9#include <linux/security.h>
10#include <linux/export.h>
11
12unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
13static struct autogroup autogroup_default;
14static atomic_t autogroup_seq_nr;
15
16void __init autogroup_init(struct task_struct *init_task)
17{
18 autogroup_default.tg = &root_task_group;
19 kref_init(&autogroup_default.kref);
20 init_rwsem(&autogroup_default.lock);
21 init_task->signal->autogroup = &autogroup_default;
22}
23
24void autogroup_free(struct task_group *tg)
25{
26 kfree(tg->autogroup);
27}
28
29static inline void autogroup_destroy(struct kref *kref)
30{
31 struct autogroup *ag = container_of(kref, struct autogroup, kref);
32
33#ifdef CONFIG_RT_GROUP_SCHED
34 /* We've redirected RT tasks to the root task group... */
35 ag->tg->rt_se = NULL;
36 ag->tg->rt_rq = NULL;
37#endif
38 sched_destroy_group(ag->tg);
39}
40
41static inline void autogroup_kref_put(struct autogroup *ag)
42{
43 kref_put(&ag->kref, autogroup_destroy);
44}
45
46static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
47{
48 kref_get(&ag->kref);
49 return ag;
50}
51
52static inline struct autogroup *autogroup_task_get(struct task_struct *p)
53{
54 struct autogroup *ag;
55 unsigned long flags;
56
57 if (!lock_task_sighand(p, &flags))
58 return autogroup_kref_get(&autogroup_default);
59
60 ag = autogroup_kref_get(p->signal->autogroup);
61 unlock_task_sighand(p, &flags);
62
63 return ag;
64}
65
66static inline struct autogroup *autogroup_create(void)
67{
68 struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
69 struct task_group *tg;
70
71 if (!ag)
72 goto out_fail;
73
74 tg = sched_create_group(&root_task_group);
75
76 if (IS_ERR(tg))
77 goto out_free;
78
79 kref_init(&ag->kref);
80 init_rwsem(&ag->lock);
81 ag->id = atomic_inc_return(&autogroup_seq_nr);
82 ag->tg = tg;
83#ifdef CONFIG_RT_GROUP_SCHED
84 /*
85 * Autogroup RT tasks are redirected to the root task group
86 * so we don't have to move tasks around upon policy change,
87 * or flail around trying to allocate bandwidth on the fly.
88 * A bandwidth exception in __sched_setscheduler() allows
89 * the policy change to proceed. Thereafter, task_group()
90 * returns &root_task_group, so zero bandwidth is required.
91 */
92 free_rt_sched_group(tg);
93 tg->rt_se = root_task_group.rt_se;
94 tg->rt_rq = root_task_group.rt_rq;
95#endif
96 tg->autogroup = ag;
97
98 return ag;
99
100out_free:
101 kfree(ag);
102out_fail:
103 if (printk_ratelimit()) {
104 printk(KERN_WARNING "autogroup_create: %s failure.\n",
105 ag ? "sched_create_group()" : "kmalloc()");
106 }
107
108 return autogroup_kref_get(&autogroup_default);
109}
110
111bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)
112{
113 if (tg != &root_task_group)
114 return false;
115
116 if (p->sched_class != &fair_sched_class)
117 return false;
118
119 /*
120 * We can only assume the task group can't go away on us if
121 * autogroup_move_group() can see us on ->thread_group list.
122 */
123 if (p->flags & PF_EXITING)
124 return false;
125
126 return true;
127}
128
129static void
130autogroup_move_group(struct task_struct *p, struct autogroup *ag)
131{
132 struct autogroup *prev;
133 struct task_struct *t;
134 unsigned long flags;
135
136 BUG_ON(!lock_task_sighand(p, &flags));
137
138 prev = p->signal->autogroup;
139 if (prev == ag) {
140 unlock_task_sighand(p, &flags);
141 return;
142 }
143
144 p->signal->autogroup = autogroup_kref_get(ag);
145
146 if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))
147 goto out;
148
149 t = p;
150 do {
151 sched_move_task(t);
152 } while_each_thread(p, t);
153
154out:
155 unlock_task_sighand(p, &flags);
156 autogroup_kref_put(prev);
157}
158
159/* Allocates GFP_KERNEL, cannot be called under any spinlock */
160void sched_autogroup_create_attach(struct task_struct *p)
161{
162 struct autogroup *ag = autogroup_create();
163
164 autogroup_move_group(p, ag);
165 /* drop extra reference added by autogroup_create() */
166 autogroup_kref_put(ag);
167}
168EXPORT_SYMBOL(sched_autogroup_create_attach);
169
170/* Cannot be called under siglock. Currently has no users */
171void sched_autogroup_detach(struct task_struct *p)
172{
173 autogroup_move_group(p, &autogroup_default);
174}
175EXPORT_SYMBOL(sched_autogroup_detach);
176
177void sched_autogroup_fork(struct signal_struct *sig)
178{
179 sig->autogroup = autogroup_task_get(current);
180}
181
182void sched_autogroup_exit(struct signal_struct *sig)
183{
184 autogroup_kref_put(sig->autogroup);
185}
186
187static int __init setup_autogroup(char *str)
188{
189 sysctl_sched_autogroup_enabled = 0;
190
191 return 1;
192}
193
194__setup("noautogroup", setup_autogroup);
195
196#ifdef CONFIG_PROC_FS
197
198int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice)
199{
200 static unsigned long next = INITIAL_JIFFIES;
201 struct autogroup *ag;
202 int err;
203
204 if (*nice < -20 || *nice > 19)
205 return -EINVAL;
206
207 err = security_task_setnice(current, *nice);
208 if (err)
209 return err;
210
211 if (*nice < 0 && !can_nice(current, *nice))
212 return -EPERM;
213
214 /* this is a heavy operation taking global locks.. */
215 if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
216 return -EAGAIN;
217
218 next = HZ / 10 + jiffies;
219 ag = autogroup_task_get(p);
220
221 down_write(&ag->lock);
222 err = sched_group_set_shares(ag->tg, prio_to_weight[*nice + 20]);
223 if (!err)
224 ag->nice = *nice;
225 up_write(&ag->lock);
226
227 autogroup_kref_put(ag);
228
229 return err;
230}
231
232void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
233{
234 struct autogroup *ag = autogroup_task_get(p);
235
236 if (!task_group_is_autogroup(ag->tg))
237 goto out;
238
239 down_read(&ag->lock);
240 seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
241 up_read(&ag->lock);
242
243out:
244 autogroup_kref_put(ag);
245}
246#endif /* CONFIG_PROC_FS */
247
248#ifdef CONFIG_SCHED_DEBUG
249int autogroup_path(struct task_group *tg, char *buf, int buflen)
250{
251 if (!task_group_is_autogroup(tg))
252 return 0;
253
254 return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
255}
256#endif /* CONFIG_SCHED_DEBUG */
257
258#endif /* CONFIG_SCHED_AUTOGROUP */
diff --git a/kernel/sched/auto_group.h b/kernel/sched/auto_group.h
new file mode 100644
index 000000000000..8bd047142816
--- /dev/null
+++ b/kernel/sched/auto_group.h
@@ -0,0 +1,64 @@
1#ifdef CONFIG_SCHED_AUTOGROUP
2
3#include <linux/kref.h>
4#include <linux/rwsem.h>
5
6struct autogroup {
7 /*
8 * reference doesn't mean how many thread attach to this
9 * autogroup now. It just stands for the number of task
10 * could use this autogroup.
11 */
12 struct kref kref;
13 struct task_group *tg;
14 struct rw_semaphore lock;
15 unsigned long id;
16 int nice;
17};
18
19extern void autogroup_init(struct task_struct *init_task);
20extern void autogroup_free(struct task_group *tg);
21
22static inline bool task_group_is_autogroup(struct task_group *tg)
23{
24 return !!tg->autogroup;
25}
26
27extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg);
28
29static inline struct task_group *
30autogroup_task_group(struct task_struct *p, struct task_group *tg)
31{
32 int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
33
34 if (enabled && task_wants_autogroup(p, tg))
35 return p->signal->autogroup->tg;
36
37 return tg;
38}
39
40extern int autogroup_path(struct task_group *tg, char *buf, int buflen);
41
42#else /* !CONFIG_SCHED_AUTOGROUP */
43
44static inline void autogroup_init(struct task_struct *init_task) { }
45static inline void autogroup_free(struct task_group *tg) { }
46static inline bool task_group_is_autogroup(struct task_group *tg)
47{
48 return 0;
49}
50
51static inline struct task_group *
52autogroup_task_group(struct task_struct *p, struct task_group *tg)
53{
54 return tg;
55}
56
57#ifdef CONFIG_SCHED_DEBUG
58static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
59{
60 return 0;
61}
62#endif
63
64#endif /* CONFIG_SCHED_AUTOGROUP */
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
new file mode 100644
index 000000000000..c685e31492df
--- /dev/null
+++ b/kernel/sched/clock.c
@@ -0,0 +1,350 @@
1/*
2 * sched_clock for unstable cpu clocks
3 *
4 * Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
5 *
6 * Updates and enhancements:
7 * Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
8 *
9 * Based on code by:
10 * Ingo Molnar <mingo@redhat.com>
11 * Guillaume Chazarain <guichaz@gmail.com>
12 *
13 *
14 * What:
15 *
16 * cpu_clock(i) provides a fast (execution time) high resolution
17 * clock with bounded drift between CPUs. The value of cpu_clock(i)
18 * is monotonic for constant i. The timestamp returned is in nanoseconds.
19 *
20 * ######################### BIG FAT WARNING ##########################
21 * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
22 * # go backwards !! #
23 * ####################################################################
24 *
25 * There is no strict promise about the base, although it tends to start
26 * at 0 on boot (but people really shouldn't rely on that).
27 *
28 * cpu_clock(i) -- can be used from any context, including NMI.
29 * sched_clock_cpu(i) -- must be used with local IRQs disabled (implied by NMI)
30 * local_clock() -- is cpu_clock() on the current cpu.
31 *
32 * How:
33 *
34 * The implementation either uses sched_clock() when
35 * !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
36 * sched_clock() is assumed to provide these properties (mostly it means
37 * the architecture provides a globally synchronized highres time source).
38 *
39 * Otherwise it tries to create a semi stable clock from a mixture of other
40 * clocks, including:
41 *
42 * - GTOD (clock monotomic)
43 * - sched_clock()
44 * - explicit idle events
45 *
46 * We use GTOD as base and use sched_clock() deltas to improve resolution. The
47 * deltas are filtered to provide monotonicity and keeping it within an
48 * expected window.
49 *
50 * Furthermore, explicit sleep and wakeup hooks allow us to account for time
51 * that is otherwise invisible (TSC gets stopped).
52 *
53 *
54 * Notes:
55 *
56 * The !IRQ-safetly of sched_clock() and sched_clock_cpu() comes from things
57 * like cpufreq interrupts that can change the base clock (TSC) multiplier
58 * and cause funny jumps in time -- although the filtering provided by
59 * sched_clock_cpu() should mitigate serious artifacts we cannot rely on it
60 * in general since for !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK we fully rely on
61 * sched_clock().
62 */
63#include <linux/spinlock.h>
64#include <linux/hardirq.h>
65#include <linux/export.h>
66#include <linux/percpu.h>
67#include <linux/ktime.h>
68#include <linux/sched.h>
69
70/*
71 * Scheduler clock - returns current time in nanosec units.
72 * This is default implementation.
73 * Architectures and sub-architectures can override this.
74 */
75unsigned long long __attribute__((weak)) sched_clock(void)
76{
77 return (unsigned long long)(jiffies - INITIAL_JIFFIES)
78 * (NSEC_PER_SEC / HZ);
79}
80EXPORT_SYMBOL_GPL(sched_clock);
81
82__read_mostly int sched_clock_running;
83
84#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
85__read_mostly int sched_clock_stable;
86
87struct sched_clock_data {
88 u64 tick_raw;
89 u64 tick_gtod;
90 u64 clock;
91};
92
93static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
94
95static inline struct sched_clock_data *this_scd(void)
96{
97 return &__get_cpu_var(sched_clock_data);
98}
99
100static inline struct sched_clock_data *cpu_sdc(int cpu)
101{
102 return &per_cpu(sched_clock_data, cpu);
103}
104
105void sched_clock_init(void)
106{
107 u64 ktime_now = ktime_to_ns(ktime_get());
108 int cpu;
109
110 for_each_possible_cpu(cpu) {
111 struct sched_clock_data *scd = cpu_sdc(cpu);
112
113 scd->tick_raw = 0;
114 scd->tick_gtod = ktime_now;
115 scd->clock = ktime_now;
116 }
117
118 sched_clock_running = 1;
119}
120
121/*
122 * min, max except they take wrapping into account
123 */
124
125static inline u64 wrap_min(u64 x, u64 y)
126{
127 return (s64)(x - y) < 0 ? x : y;
128}
129
130static inline u64 wrap_max(u64 x, u64 y)
131{
132 return (s64)(x - y) > 0 ? x : y;
133}
134
135/*
136 * update the percpu scd from the raw @now value
137 *
138 * - filter out backward motion
139 * - use the GTOD tick value to create a window to filter crazy TSC values
140 */
141static u64 sched_clock_local(struct sched_clock_data *scd)
142{
143 u64 now, clock, old_clock, min_clock, max_clock;
144 s64 delta;
145
146again:
147 now = sched_clock();
148 delta = now - scd->tick_raw;
149 if (unlikely(delta < 0))
150 delta = 0;
151
152 old_clock = scd->clock;
153
154 /*
155 * scd->clock = clamp(scd->tick_gtod + delta,
156 * max(scd->tick_gtod, scd->clock),
157 * scd->tick_gtod + TICK_NSEC);
158 */
159
160 clock = scd->tick_gtod + delta;
161 min_clock = wrap_max(scd->tick_gtod, old_clock);
162 max_clock = wrap_max(old_clock, scd->tick_gtod + TICK_NSEC);
163
164 clock = wrap_max(clock, min_clock);
165 clock = wrap_min(clock, max_clock);
166
167 if (cmpxchg64(&scd->clock, old_clock, clock) != old_clock)
168 goto again;
169
170 return clock;
171}
172
173static u64 sched_clock_remote(struct sched_clock_data *scd)
174{
175 struct sched_clock_data *my_scd = this_scd();
176 u64 this_clock, remote_clock;
177 u64 *ptr, old_val, val;
178
179 sched_clock_local(my_scd);
180again:
181 this_clock = my_scd->clock;
182 remote_clock = scd->clock;
183
184 /*
185 * Use the opportunity that we have both locks
186 * taken to couple the two clocks: we take the
187 * larger time as the latest time for both
188 * runqueues. (this creates monotonic movement)
189 */
190 if (likely((s64)(remote_clock - this_clock) < 0)) {
191 ptr = &scd->clock;
192 old_val = remote_clock;
193 val = this_clock;
194 } else {
195 /*
196 * Should be rare, but possible:
197 */
198 ptr = &my_scd->clock;
199 old_val = this_clock;
200 val = remote_clock;
201 }
202
203 if (cmpxchg64(ptr, old_val, val) != old_val)
204 goto again;
205
206 return val;
207}
208
209/*
210 * Similar to cpu_clock(), but requires local IRQs to be disabled.
211 *
212 * See cpu_clock().
213 */
214u64 sched_clock_cpu(int cpu)
215{
216 struct sched_clock_data *scd;
217 u64 clock;
218
219 WARN_ON_ONCE(!irqs_disabled());
220
221 if (sched_clock_stable)
222 return sched_clock();
223
224 if (unlikely(!sched_clock_running))
225 return 0ull;
226
227 scd = cpu_sdc(cpu);
228
229 if (cpu != smp_processor_id())
230 clock = sched_clock_remote(scd);
231 else
232 clock = sched_clock_local(scd);
233
234 return clock;
235}
236
237void sched_clock_tick(void)
238{
239 struct sched_clock_data *scd;
240 u64 now, now_gtod;
241
242 if (sched_clock_stable)
243 return;
244
245 if (unlikely(!sched_clock_running))
246 return;
247
248 WARN_ON_ONCE(!irqs_disabled());
249
250 scd = this_scd();
251 now_gtod = ktime_to_ns(ktime_get());
252 now = sched_clock();
253
254 scd->tick_raw = now;
255 scd->tick_gtod = now_gtod;
256 sched_clock_local(scd);
257}
258
259/*
260 * We are going deep-idle (irqs are disabled):
261 */
262void sched_clock_idle_sleep_event(void)
263{
264 sched_clock_cpu(smp_processor_id());
265}
266EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
267
268/*
269 * We just idled delta nanoseconds (called with irqs disabled):
270 */
271void sched_clock_idle_wakeup_event(u64 delta_ns)
272{
273 if (timekeeping_suspended)
274 return;
275
276 sched_clock_tick();
277 touch_softlockup_watchdog();
278}
279EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
280
281/*
282 * As outlined at the top, provides a fast, high resolution, nanosecond
283 * time source that is monotonic per cpu argument and has bounded drift
284 * between cpus.
285 *
286 * ######################### BIG FAT WARNING ##########################
287 * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
288 * # go backwards !! #
289 * ####################################################################
290 */
291u64 cpu_clock(int cpu)
292{
293 u64 clock;
294 unsigned long flags;
295
296 local_irq_save(flags);
297 clock = sched_clock_cpu(cpu);
298 local_irq_restore(flags);
299
300 return clock;
301}
302
303/*
304 * Similar to cpu_clock() for the current cpu. Time will only be observed
305 * to be monotonic if care is taken to only compare timestampt taken on the
306 * same CPU.
307 *
308 * See cpu_clock().
309 */
310u64 local_clock(void)
311{
312 u64 clock;
313 unsigned long flags;
314
315 local_irq_save(flags);
316 clock = sched_clock_cpu(smp_processor_id());
317 local_irq_restore(flags);
318
319 return clock;
320}
321
322#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
323
324void sched_clock_init(void)
325{
326 sched_clock_running = 1;
327}
328
329u64 sched_clock_cpu(int cpu)
330{
331 if (unlikely(!sched_clock_running))
332 return 0;
333
334 return sched_clock();
335}
336
337u64 cpu_clock(int cpu)
338{
339 return sched_clock_cpu(cpu);
340}
341
342u64 local_clock(void)
343{
344 return sched_clock_cpu(0);
345}
346
347#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
348
349EXPORT_SYMBOL_GPL(cpu_clock);
350EXPORT_SYMBOL_GPL(local_clock);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
new file mode 100644
index 000000000000..cdf51a2adc26
--- /dev/null
+++ b/kernel/sched/core.c
@@ -0,0 +1,8119 @@
1/*
2 * kernel/sched/core.c
3 *
4 * Kernel scheduler and related syscalls
5 *
6 * Copyright (C) 1991-2002 Linus Torvalds
7 *
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
11 * by Andrea Arcangeli
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
22 * by Peter Williams
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
27 */
28
29#include <linux/mm.h>
30#include <linux/module.h>
31#include <linux/nmi.h>
32#include <linux/init.h>
33#include <linux/uaccess.h>
34#include <linux/highmem.h>
35#include <asm/mmu_context.h>
36#include <linux/interrupt.h>
37#include <linux/capability.h>
38#include <linux/completion.h>
39#include <linux/kernel_stat.h>
40#include <linux/debug_locks.h>
41#include <linux/perf_event.h>
42#include <linux/security.h>
43#include <linux/notifier.h>
44#include <linux/profile.h>
45#include <linux/freezer.h>
46#include <linux/vmalloc.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/pid_namespace.h>
50#include <linux/smp.h>
51#include <linux/threads.h>
52#include <linux/timer.h>
53#include <linux/rcupdate.h>
54#include <linux/cpu.h>
55#include <linux/cpuset.h>
56#include <linux/percpu.h>
57#include <linux/proc_fs.h>
58#include <linux/seq_file.h>
59#include <linux/sysctl.h>
60#include <linux/syscalls.h>
61#include <linux/times.h>
62#include <linux/tsacct_kern.h>
63#include <linux/kprobes.h>
64#include <linux/delayacct.h>
65#include <linux/unistd.h>
66#include <linux/pagemap.h>
67#include <linux/hrtimer.h>
68#include <linux/tick.h>
69#include <linux/debugfs.h>
70#include <linux/ctype.h>
71#include <linux/ftrace.h>
72#include <linux/slab.h>
73#include <linux/init_task.h>
74
75#include <asm/tlb.h>
76#include <asm/irq_regs.h>
77#ifdef CONFIG_PARAVIRT
78#include <asm/paravirt.h>
79#endif
80
81#include "sched.h"
82#include "../workqueue_sched.h"
83
84#define CREATE_TRACE_POINTS
85#include <trace/events/sched.h>
86
87void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
88{
89 unsigned long delta;
90 ktime_t soft, hard, now;
91
92 for (;;) {
93 if (hrtimer_active(period_timer))
94 break;
95
96 now = hrtimer_cb_get_time(period_timer);
97 hrtimer_forward(period_timer, now, period);
98
99 soft = hrtimer_get_softexpires(period_timer);
100 hard = hrtimer_get_expires(period_timer);
101 delta = ktime_to_ns(ktime_sub(hard, soft));
102 __hrtimer_start_range_ns(period_timer, soft, delta,
103 HRTIMER_MODE_ABS_PINNED, 0);
104 }
105}
106
107DEFINE_MUTEX(sched_domains_mutex);
108DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
109
110static void update_rq_clock_task(struct rq *rq, s64 delta);
111
112void update_rq_clock(struct rq *rq)
113{
114 s64 delta;
115
116 if (rq->skip_clock_update > 0)
117 return;
118
119 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
120 rq->clock += delta;
121 update_rq_clock_task(rq, delta);
122}
123
124/*
125 * Debugging: various feature bits
126 */
127
128#define SCHED_FEAT(name, enabled) \
129 (1UL << __SCHED_FEAT_##name) * enabled |
130
131const_debug unsigned int sysctl_sched_features =
132#include "features.h"
133 0;
134
135#undef SCHED_FEAT
136
137#ifdef CONFIG_SCHED_DEBUG
138#define SCHED_FEAT(name, enabled) \
139 #name ,
140
141static __read_mostly char *sched_feat_names[] = {
142#include "features.h"
143 NULL
144};
145
146#undef SCHED_FEAT
147
148static int sched_feat_show(struct seq_file *m, void *v)
149{
150 int i;
151
152 for (i = 0; i < __SCHED_FEAT_NR; i++) {
153 if (!(sysctl_sched_features & (1UL << i)))
154 seq_puts(m, "NO_");
155 seq_printf(m, "%s ", sched_feat_names[i]);
156 }
157 seq_puts(m, "\n");
158
159 return 0;
160}
161
162#ifdef HAVE_JUMP_LABEL
163
164#define jump_label_key__true jump_label_key_enabled
165#define jump_label_key__false jump_label_key_disabled
166
167#define SCHED_FEAT(name, enabled) \
168 jump_label_key__##enabled ,
169
170struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR] = {
171#include "features.h"
172};
173
174#undef SCHED_FEAT
175
176static void sched_feat_disable(int i)
177{
178 if (jump_label_enabled(&sched_feat_keys[i]))
179 jump_label_dec(&sched_feat_keys[i]);
180}
181
182static void sched_feat_enable(int i)
183{
184 if (!jump_label_enabled(&sched_feat_keys[i]))
185 jump_label_inc(&sched_feat_keys[i]);
186}
187#else
188static void sched_feat_disable(int i) { };
189static void sched_feat_enable(int i) { };
190#endif /* HAVE_JUMP_LABEL */
191
192static ssize_t
193sched_feat_write(struct file *filp, const char __user *ubuf,
194 size_t cnt, loff_t *ppos)
195{
196 char buf[64];
197 char *cmp;
198 int neg = 0;
199 int i;
200
201 if (cnt > 63)
202 cnt = 63;
203
204 if (copy_from_user(&buf, ubuf, cnt))
205 return -EFAULT;
206
207 buf[cnt] = 0;
208 cmp = strstrip(buf);
209
210 if (strncmp(cmp, "NO_", 3) == 0) {
211 neg = 1;
212 cmp += 3;
213 }
214
215 for (i = 0; i < __SCHED_FEAT_NR; i++) {
216 if (strcmp(cmp, sched_feat_names[i]) == 0) {
217 if (neg) {
218 sysctl_sched_features &= ~(1UL << i);
219 sched_feat_disable(i);
220 } else {
221 sysctl_sched_features |= (1UL << i);
222 sched_feat_enable(i);
223 }
224 break;
225 }
226 }
227
228 if (i == __SCHED_FEAT_NR)
229 return -EINVAL;
230
231 *ppos += cnt;
232
233 return cnt;
234}
235
236static int sched_feat_open(struct inode *inode, struct file *filp)
237{
238 return single_open(filp, sched_feat_show, NULL);
239}
240
241static const struct file_operations sched_feat_fops = {
242 .open = sched_feat_open,
243 .write = sched_feat_write,
244 .read = seq_read,
245 .llseek = seq_lseek,
246 .release = single_release,
247};
248
249static __init int sched_init_debug(void)
250{
251 debugfs_create_file("sched_features", 0644, NULL, NULL,
252 &sched_feat_fops);
253
254 return 0;
255}
256late_initcall(sched_init_debug);
257#endif /* CONFIG_SCHED_DEBUG */
258
259/*
260 * Number of tasks to iterate in a single balance run.
261 * Limited because this is done with IRQs disabled.
262 */
263const_debug unsigned int sysctl_sched_nr_migrate = 32;
264
265/*
266 * period over which we average the RT time consumption, measured
267 * in ms.
268 *
269 * default: 1s
270 */
271const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
272
273/*
274 * period over which we measure -rt task cpu usage in us.
275 * default: 1s
276 */
277unsigned int sysctl_sched_rt_period = 1000000;
278
279__read_mostly int scheduler_running;
280
281/*
282 * part of the period that we allow rt tasks to run in us.
283 * default: 0.95s
284 */
285int sysctl_sched_rt_runtime = 950000;
286
287
288
289/*
290 * __task_rq_lock - lock the rq @p resides on.
291 */
292static inline struct rq *__task_rq_lock(struct task_struct *p)
293 __acquires(rq->lock)
294{
295 struct rq *rq;
296
297 lockdep_assert_held(&p->pi_lock);
298
299 for (;;) {
300 rq = task_rq(p);
301 raw_spin_lock(&rq->lock);
302 if (likely(rq == task_rq(p)))
303 return rq;
304 raw_spin_unlock(&rq->lock);
305 }
306}
307
308/*
309 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
310 */
311static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
312 __acquires(p->pi_lock)
313 __acquires(rq->lock)
314{
315 struct rq *rq;
316
317 for (;;) {
318 raw_spin_lock_irqsave(&p->pi_lock, *flags);
319 rq = task_rq(p);
320 raw_spin_lock(&rq->lock);
321 if (likely(rq == task_rq(p)))
322 return rq;
323 raw_spin_unlock(&rq->lock);
324 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
325 }
326}
327
328static void __task_rq_unlock(struct rq *rq)
329 __releases(rq->lock)
330{
331 raw_spin_unlock(&rq->lock);
332}
333
334static inline void
335task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
336 __releases(rq->lock)
337 __releases(p->pi_lock)
338{
339 raw_spin_unlock(&rq->lock);
340 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
341}
342
343/*
344 * this_rq_lock - lock this runqueue and disable interrupts.
345 */
346static struct rq *this_rq_lock(void)
347 __acquires(rq->lock)
348{
349 struct rq *rq;
350
351 local_irq_disable();
352 rq = this_rq();
353 raw_spin_lock(&rq->lock);
354
355 return rq;
356}
357
358#ifdef CONFIG_SCHED_HRTICK
359/*
360 * Use HR-timers to deliver accurate preemption points.
361 *
362 * Its all a bit involved since we cannot program an hrt while holding the
363 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
364 * reschedule event.
365 *
366 * When we get rescheduled we reprogram the hrtick_timer outside of the
367 * rq->lock.
368 */
369
370static void hrtick_clear(struct rq *rq)
371{
372 if (hrtimer_active(&rq->hrtick_timer))
373 hrtimer_cancel(&rq->hrtick_timer);
374}
375
376/*
377 * High-resolution timer tick.
378 * Runs from hardirq context with interrupts disabled.
379 */
380static enum hrtimer_restart hrtick(struct hrtimer *timer)
381{
382 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
383
384 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
385
386 raw_spin_lock(&rq->lock);
387 update_rq_clock(rq);
388 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
389 raw_spin_unlock(&rq->lock);
390
391 return HRTIMER_NORESTART;
392}
393
394#ifdef CONFIG_SMP
395/*
396 * called from hardirq (IPI) context
397 */
398static void __hrtick_start(void *arg)
399{
400 struct rq *rq = arg;
401
402 raw_spin_lock(&rq->lock);
403 hrtimer_restart(&rq->hrtick_timer);
404 rq->hrtick_csd_pending = 0;
405 raw_spin_unlock(&rq->lock);
406}
407
408/*
409 * Called to set the hrtick timer state.
410 *
411 * called with rq->lock held and irqs disabled
412 */
413void hrtick_start(struct rq *rq, u64 delay)
414{
415 struct hrtimer *timer = &rq->hrtick_timer;
416 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
417
418 hrtimer_set_expires(timer, time);
419
420 if (rq == this_rq()) {
421 hrtimer_restart(timer);
422 } else if (!rq->hrtick_csd_pending) {
423 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
424 rq->hrtick_csd_pending = 1;
425 }
426}
427
428static int
429hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
430{
431 int cpu = (int)(long)hcpu;
432
433 switch (action) {
434 case CPU_UP_CANCELED:
435 case CPU_UP_CANCELED_FROZEN:
436 case CPU_DOWN_PREPARE:
437 case CPU_DOWN_PREPARE_FROZEN:
438 case CPU_DEAD:
439 case CPU_DEAD_FROZEN:
440 hrtick_clear(cpu_rq(cpu));
441 return NOTIFY_OK;
442 }
443
444 return NOTIFY_DONE;
445}
446
447static __init void init_hrtick(void)
448{
449 hotcpu_notifier(hotplug_hrtick, 0);
450}
451#else
452/*
453 * Called to set the hrtick timer state.
454 *
455 * called with rq->lock held and irqs disabled
456 */
457void hrtick_start(struct rq *rq, u64 delay)
458{
459 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
460 HRTIMER_MODE_REL_PINNED, 0);
461}
462
463static inline void init_hrtick(void)
464{
465}
466#endif /* CONFIG_SMP */
467
468static void init_rq_hrtick(struct rq *rq)
469{
470#ifdef CONFIG_SMP
471 rq->hrtick_csd_pending = 0;
472
473 rq->hrtick_csd.flags = 0;
474 rq->hrtick_csd.func = __hrtick_start;
475 rq->hrtick_csd.info = rq;
476#endif
477
478 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
479 rq->hrtick_timer.function = hrtick;
480}
481#else /* CONFIG_SCHED_HRTICK */
482static inline void hrtick_clear(struct rq *rq)
483{
484}
485
486static inline void init_rq_hrtick(struct rq *rq)
487{
488}
489
490static inline void init_hrtick(void)
491{
492}
493#endif /* CONFIG_SCHED_HRTICK */
494
495/*
496 * resched_task - mark a task 'to be rescheduled now'.
497 *
498 * On UP this means the setting of the need_resched flag, on SMP it
499 * might also involve a cross-CPU call to trigger the scheduler on
500 * the target CPU.
501 */
502#ifdef CONFIG_SMP
503
504#ifndef tsk_is_polling
505#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
506#endif
507
508void resched_task(struct task_struct *p)
509{
510 int cpu;
511
512 assert_raw_spin_locked(&task_rq(p)->lock);
513
514 if (test_tsk_need_resched(p))
515 return;
516
517 set_tsk_need_resched(p);
518
519 cpu = task_cpu(p);
520 if (cpu == smp_processor_id())
521 return;
522
523 /* NEED_RESCHED must be visible before we test polling */
524 smp_mb();
525 if (!tsk_is_polling(p))
526 smp_send_reschedule(cpu);
527}
528
529void resched_cpu(int cpu)
530{
531 struct rq *rq = cpu_rq(cpu);
532 unsigned long flags;
533
534 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
535 return;
536 resched_task(cpu_curr(cpu));
537 raw_spin_unlock_irqrestore(&rq->lock, flags);
538}
539
540#ifdef CONFIG_NO_HZ
541/*
542 * In the semi idle case, use the nearest busy cpu for migrating timers
543 * from an idle cpu. This is good for power-savings.
544 *
545 * We don't do similar optimization for completely idle system, as
546 * selecting an idle cpu will add more delays to the timers than intended
547 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
548 */
549int get_nohz_timer_target(void)
550{
551 int cpu = smp_processor_id();
552 int i;
553 struct sched_domain *sd;
554
555 rcu_read_lock();
556 for_each_domain(cpu, sd) {
557 for_each_cpu(i, sched_domain_span(sd)) {
558 if (!idle_cpu(i)) {
559 cpu = i;
560 goto unlock;
561 }
562 }
563 }
564unlock:
565 rcu_read_unlock();
566 return cpu;
567}
568/*
569 * When add_timer_on() enqueues a timer into the timer wheel of an
570 * idle CPU then this timer might expire before the next timer event
571 * which is scheduled to wake up that CPU. In case of a completely
572 * idle system the next event might even be infinite time into the
573 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
574 * leaves the inner idle loop so the newly added timer is taken into
575 * account when the CPU goes back to idle and evaluates the timer
576 * wheel for the next timer event.
577 */
578void wake_up_idle_cpu(int cpu)
579{
580 struct rq *rq = cpu_rq(cpu);
581
582 if (cpu == smp_processor_id())
583 return;
584
585 /*
586 * This is safe, as this function is called with the timer
587 * wheel base lock of (cpu) held. When the CPU is on the way
588 * to idle and has not yet set rq->curr to idle then it will
589 * be serialized on the timer wheel base lock and take the new
590 * timer into account automatically.
591 */
592 if (rq->curr != rq->idle)
593 return;
594
595 /*
596 * We can set TIF_RESCHED on the idle task of the other CPU
597 * lockless. The worst case is that the other CPU runs the
598 * idle task through an additional NOOP schedule()
599 */
600 set_tsk_need_resched(rq->idle);
601
602 /* NEED_RESCHED must be visible before we test polling */
603 smp_mb();
604 if (!tsk_is_polling(rq->idle))
605 smp_send_reschedule(cpu);
606}
607
608static inline bool got_nohz_idle_kick(void)
609{
610 int cpu = smp_processor_id();
611 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
612}
613
614#else /* CONFIG_NO_HZ */
615
616static inline bool got_nohz_idle_kick(void)
617{
618 return false;
619}
620
621#endif /* CONFIG_NO_HZ */
622
623void sched_avg_update(struct rq *rq)
624{
625 s64 period = sched_avg_period();
626
627 while ((s64)(rq->clock - rq->age_stamp) > period) {
628 /*
629 * Inline assembly required to prevent the compiler
630 * optimising this loop into a divmod call.
631 * See __iter_div_u64_rem() for another example of this.
632 */
633 asm("" : "+rm" (rq->age_stamp));
634 rq->age_stamp += period;
635 rq->rt_avg /= 2;
636 }
637}
638
639#else /* !CONFIG_SMP */
640void resched_task(struct task_struct *p)
641{
642 assert_raw_spin_locked(&task_rq(p)->lock);
643 set_tsk_need_resched(p);
644}
645#endif /* CONFIG_SMP */
646
647#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
648 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
649/*
650 * Iterate task_group tree rooted at *from, calling @down when first entering a
651 * node and @up when leaving it for the final time.
652 *
653 * Caller must hold rcu_lock or sufficient equivalent.
654 */
655int walk_tg_tree_from(struct task_group *from,
656 tg_visitor down, tg_visitor up, void *data)
657{
658 struct task_group *parent, *child;
659 int ret;
660
661 parent = from;
662
663down:
664 ret = (*down)(parent, data);
665 if (ret)
666 goto out;
667 list_for_each_entry_rcu(child, &parent->children, siblings) {
668 parent = child;
669 goto down;
670
671up:
672 continue;
673 }
674 ret = (*up)(parent, data);
675 if (ret || parent == from)
676 goto out;
677
678 child = parent;
679 parent = parent->parent;
680 if (parent)
681 goto up;
682out:
683 return ret;
684}
685
686int tg_nop(struct task_group *tg, void *data)
687{
688 return 0;
689}
690#endif
691
692void update_cpu_load(struct rq *this_rq);
693
694static void set_load_weight(struct task_struct *p)
695{
696 int prio = p->static_prio - MAX_RT_PRIO;
697 struct load_weight *load = &p->se.load;
698
699 /*
700 * SCHED_IDLE tasks get minimal weight:
701 */
702 if (p->policy == SCHED_IDLE) {
703 load->weight = scale_load(WEIGHT_IDLEPRIO);
704 load->inv_weight = WMULT_IDLEPRIO;
705 return;
706 }
707
708 load->weight = scale_load(prio_to_weight[prio]);
709 load->inv_weight = prio_to_wmult[prio];
710}
711
712static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
713{
714 update_rq_clock(rq);
715 sched_info_queued(p);
716 p->sched_class->enqueue_task(rq, p, flags);
717}
718
719static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
720{
721 update_rq_clock(rq);
722 sched_info_dequeued(p);
723 p->sched_class->dequeue_task(rq, p, flags);
724}
725
726/*
727 * activate_task - move a task to the runqueue.
728 */
729void activate_task(struct rq *rq, struct task_struct *p, int flags)
730{
731 if (task_contributes_to_load(p))
732 rq->nr_uninterruptible--;
733
734 enqueue_task(rq, p, flags);
735}
736
737/*
738 * deactivate_task - remove a task from the runqueue.
739 */
740void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
741{
742 if (task_contributes_to_load(p))
743 rq->nr_uninterruptible++;
744
745 dequeue_task(rq, p, flags);
746}
747
748#ifdef CONFIG_IRQ_TIME_ACCOUNTING
749
750/*
751 * There are no locks covering percpu hardirq/softirq time.
752 * They are only modified in account_system_vtime, on corresponding CPU
753 * with interrupts disabled. So, writes are safe.
754 * They are read and saved off onto struct rq in update_rq_clock().
755 * This may result in other CPU reading this CPU's irq time and can
756 * race with irq/account_system_vtime on this CPU. We would either get old
757 * or new value with a side effect of accounting a slice of irq time to wrong
758 * task when irq is in progress while we read rq->clock. That is a worthy
759 * compromise in place of having locks on each irq in account_system_time.
760 */
761static DEFINE_PER_CPU(u64, cpu_hardirq_time);
762static DEFINE_PER_CPU(u64, cpu_softirq_time);
763
764static DEFINE_PER_CPU(u64, irq_start_time);
765static int sched_clock_irqtime;
766
767void enable_sched_clock_irqtime(void)
768{
769 sched_clock_irqtime = 1;
770}
771
772void disable_sched_clock_irqtime(void)
773{
774 sched_clock_irqtime = 0;
775}
776
777#ifndef CONFIG_64BIT
778static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
779
780static inline void irq_time_write_begin(void)
781{
782 __this_cpu_inc(irq_time_seq.sequence);
783 smp_wmb();
784}
785
786static inline void irq_time_write_end(void)
787{
788 smp_wmb();
789 __this_cpu_inc(irq_time_seq.sequence);
790}
791
792static inline u64 irq_time_read(int cpu)
793{
794 u64 irq_time;
795 unsigned seq;
796
797 do {
798 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
799 irq_time = per_cpu(cpu_softirq_time, cpu) +
800 per_cpu(cpu_hardirq_time, cpu);
801 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
802
803 return irq_time;
804}
805#else /* CONFIG_64BIT */
806static inline void irq_time_write_begin(void)
807{
808}
809
810static inline void irq_time_write_end(void)
811{
812}
813
814static inline u64 irq_time_read(int cpu)
815{
816 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
817}
818#endif /* CONFIG_64BIT */
819
820/*
821 * Called before incrementing preempt_count on {soft,}irq_enter
822 * and before decrementing preempt_count on {soft,}irq_exit.
823 */
824void account_system_vtime(struct task_struct *curr)
825{
826 unsigned long flags;
827 s64 delta;
828 int cpu;
829
830 if (!sched_clock_irqtime)
831 return;
832
833 local_irq_save(flags);
834
835 cpu = smp_processor_id();
836 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
837 __this_cpu_add(irq_start_time, delta);
838
839 irq_time_write_begin();
840 /*
841 * We do not account for softirq time from ksoftirqd here.
842 * We want to continue accounting softirq time to ksoftirqd thread
843 * in that case, so as not to confuse scheduler with a special task
844 * that do not consume any time, but still wants to run.
845 */
846 if (hardirq_count())
847 __this_cpu_add(cpu_hardirq_time, delta);
848 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
849 __this_cpu_add(cpu_softirq_time, delta);
850
851 irq_time_write_end();
852 local_irq_restore(flags);
853}
854EXPORT_SYMBOL_GPL(account_system_vtime);
855
856#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
857
858#ifdef CONFIG_PARAVIRT
859static inline u64 steal_ticks(u64 steal)
860{
861 if (unlikely(steal > NSEC_PER_SEC))
862 return div_u64(steal, TICK_NSEC);
863
864 return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
865}
866#endif
867
868static void update_rq_clock_task(struct rq *rq, s64 delta)
869{
870/*
871 * In theory, the compile should just see 0 here, and optimize out the call
872 * to sched_rt_avg_update. But I don't trust it...
873 */
874#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
875 s64 steal = 0, irq_delta = 0;
876#endif
877#ifdef CONFIG_IRQ_TIME_ACCOUNTING
878 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
879
880 /*
881 * Since irq_time is only updated on {soft,}irq_exit, we might run into
882 * this case when a previous update_rq_clock() happened inside a
883 * {soft,}irq region.
884 *
885 * When this happens, we stop ->clock_task and only update the
886 * prev_irq_time stamp to account for the part that fit, so that a next
887 * update will consume the rest. This ensures ->clock_task is
888 * monotonic.
889 *
890 * It does however cause some slight miss-attribution of {soft,}irq
891 * time, a more accurate solution would be to update the irq_time using
892 * the current rq->clock timestamp, except that would require using
893 * atomic ops.
894 */
895 if (irq_delta > delta)
896 irq_delta = delta;
897
898 rq->prev_irq_time += irq_delta;
899 delta -= irq_delta;
900#endif
901#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
902 if (static_branch((&paravirt_steal_rq_enabled))) {
903 u64 st;
904
905 steal = paravirt_steal_clock(cpu_of(rq));
906 steal -= rq->prev_steal_time_rq;
907
908 if (unlikely(steal > delta))
909 steal = delta;
910
911 st = steal_ticks(steal);
912 steal = st * TICK_NSEC;
913
914 rq->prev_steal_time_rq += steal;
915
916 delta -= steal;
917 }
918#endif
919
920 rq->clock_task += delta;
921
922#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
923 if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
924 sched_rt_avg_update(rq, irq_delta + steal);
925#endif
926}
927
928#ifdef CONFIG_IRQ_TIME_ACCOUNTING
929static int irqtime_account_hi_update(void)
930{
931 u64 *cpustat = kcpustat_this_cpu->cpustat;
932 unsigned long flags;
933 u64 latest_ns;
934 int ret = 0;
935
936 local_irq_save(flags);
937 latest_ns = this_cpu_read(cpu_hardirq_time);
938 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
939 ret = 1;
940 local_irq_restore(flags);
941 return ret;
942}
943
944static int irqtime_account_si_update(void)
945{
946 u64 *cpustat = kcpustat_this_cpu->cpustat;
947 unsigned long flags;
948 u64 latest_ns;
949 int ret = 0;
950
951 local_irq_save(flags);
952 latest_ns = this_cpu_read(cpu_softirq_time);
953 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
954 ret = 1;
955 local_irq_restore(flags);
956 return ret;
957}
958
959#else /* CONFIG_IRQ_TIME_ACCOUNTING */
960
961#define sched_clock_irqtime (0)
962
963#endif
964
965void sched_set_stop_task(int cpu, struct task_struct *stop)
966{
967 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
968 struct task_struct *old_stop = cpu_rq(cpu)->stop;
969
970 if (stop) {
971 /*
972 * Make it appear like a SCHED_FIFO task, its something
973 * userspace knows about and won't get confused about.
974 *
975 * Also, it will make PI more or less work without too
976 * much confusion -- but then, stop work should not
977 * rely on PI working anyway.
978 */
979 sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
980
981 stop->sched_class = &stop_sched_class;
982 }
983
984 cpu_rq(cpu)->stop = stop;
985
986 if (old_stop) {
987 /*
988 * Reset it back to a normal scheduling class so that
989 * it can die in pieces.
990 */
991 old_stop->sched_class = &rt_sched_class;
992 }
993}
994
995/*
996 * __normal_prio - return the priority that is based on the static prio
997 */
998static inline int __normal_prio(struct task_struct *p)
999{
1000 return p->static_prio;
1001}
1002
1003/*
1004 * Calculate the expected normal priority: i.e. priority
1005 * without taking RT-inheritance into account. Might be
1006 * boosted by interactivity modifiers. Changes upon fork,
1007 * setprio syscalls, and whenever the interactivity
1008 * estimator recalculates.
1009 */
1010static inline int normal_prio(struct task_struct *p)
1011{
1012 int prio;
1013
1014 if (task_has_rt_policy(p))
1015 prio = MAX_RT_PRIO-1 - p->rt_priority;
1016 else
1017 prio = __normal_prio(p);
1018 return prio;
1019}
1020
1021/*
1022 * Calculate the current priority, i.e. the priority
1023 * taken into account by the scheduler. This value might
1024 * be boosted by RT tasks, or might be boosted by
1025 * interactivity modifiers. Will be RT if the task got
1026 * RT-boosted. If not then it returns p->normal_prio.
1027 */
1028static int effective_prio(struct task_struct *p)
1029{
1030 p->normal_prio = normal_prio(p);
1031 /*
1032 * If we are RT tasks or we were boosted to RT priority,
1033 * keep the priority unchanged. Otherwise, update priority
1034 * to the normal priority:
1035 */
1036 if (!rt_prio(p->prio))
1037 return p->normal_prio;
1038 return p->prio;
1039}
1040
1041/**
1042 * task_curr - is this task currently executing on a CPU?
1043 * @p: the task in question.
1044 */
1045inline int task_curr(const struct task_struct *p)
1046{
1047 return cpu_curr(task_cpu(p)) == p;
1048}
1049
1050static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1051 const struct sched_class *prev_class,
1052 int oldprio)
1053{
1054 if (prev_class != p->sched_class) {
1055 if (prev_class->switched_from)
1056 prev_class->switched_from(rq, p);
1057 p->sched_class->switched_to(rq, p);
1058 } else if (oldprio != p->prio)
1059 p->sched_class->prio_changed(rq, p, oldprio);
1060}
1061
1062void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1063{
1064 const struct sched_class *class;
1065
1066 if (p->sched_class == rq->curr->sched_class) {
1067 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
1068 } else {
1069 for_each_class(class) {
1070 if (class == rq->curr->sched_class)
1071 break;
1072 if (class == p->sched_class) {
1073 resched_task(rq->curr);
1074 break;
1075 }
1076 }
1077 }
1078
1079 /*
1080 * A queue event has occurred, and we're going to schedule. In
1081 * this case, we can save a useless back to back clock update.
1082 */
1083 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
1084 rq->skip_clock_update = 1;
1085}
1086
1087#ifdef CONFIG_SMP
1088void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1089{
1090#ifdef CONFIG_SCHED_DEBUG
1091 /*
1092 * We should never call set_task_cpu() on a blocked task,
1093 * ttwu() will sort out the placement.
1094 */
1095 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1096 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
1097
1098#ifdef CONFIG_LOCKDEP
1099 /*
1100 * The caller should hold either p->pi_lock or rq->lock, when changing
1101 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1102 *
1103 * sched_move_task() holds both and thus holding either pins the cgroup,
1104 * see set_task_rq().
1105 *
1106 * Furthermore, all task_rq users should acquire both locks, see
1107 * task_rq_lock().
1108 */
1109 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1110 lockdep_is_held(&task_rq(p)->lock)));
1111#endif
1112#endif
1113
1114 trace_sched_migrate_task(p, new_cpu);
1115
1116 if (task_cpu(p) != new_cpu) {
1117 p->se.nr_migrations++;
1118 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
1119 }
1120
1121 __set_task_cpu(p, new_cpu);
1122}
1123
1124struct migration_arg {
1125 struct task_struct *task;
1126 int dest_cpu;
1127};
1128
1129static int migration_cpu_stop(void *data);
1130
1131/*
1132 * wait_task_inactive - wait for a thread to unschedule.
1133 *
1134 * If @match_state is nonzero, it's the @p->state value just checked and
1135 * not expected to change. If it changes, i.e. @p might have woken up,
1136 * then return zero. When we succeed in waiting for @p to be off its CPU,
1137 * we return a positive number (its total switch count). If a second call
1138 * a short while later returns the same number, the caller can be sure that
1139 * @p has remained unscheduled the whole time.
1140 *
1141 * The caller must ensure that the task *will* unschedule sometime soon,
1142 * else this function might spin for a *long* time. This function can't
1143 * be called with interrupts off, or it may introduce deadlock with
1144 * smp_call_function() if an IPI is sent by the same process we are
1145 * waiting to become inactive.
1146 */
1147unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1148{
1149 unsigned long flags;
1150 int running, on_rq;
1151 unsigned long ncsw;
1152 struct rq *rq;
1153
1154 for (;;) {
1155 /*
1156 * We do the initial early heuristics without holding
1157 * any task-queue locks at all. We'll only try to get
1158 * the runqueue lock when things look like they will
1159 * work out!
1160 */
1161 rq = task_rq(p);
1162
1163 /*
1164 * If the task is actively running on another CPU
1165 * still, just relax and busy-wait without holding
1166 * any locks.
1167 *
1168 * NOTE! Since we don't hold any locks, it's not
1169 * even sure that "rq" stays as the right runqueue!
1170 * But we don't care, since "task_running()" will
1171 * return false if the runqueue has changed and p
1172 * is actually now running somewhere else!
1173 */
1174 while (task_running(rq, p)) {
1175 if (match_state && unlikely(p->state != match_state))
1176 return 0;
1177 cpu_relax();
1178 }
1179
1180 /*
1181 * Ok, time to look more closely! We need the rq
1182 * lock now, to be *sure*. If we're wrong, we'll
1183 * just go back and repeat.
1184 */
1185 rq = task_rq_lock(p, &flags);
1186 trace_sched_wait_task(p);
1187 running = task_running(rq, p);
1188 on_rq = p->on_rq;
1189 ncsw = 0;
1190 if (!match_state || p->state == match_state)
1191 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1192 task_rq_unlock(rq, p, &flags);
1193
1194 /*
1195 * If it changed from the expected state, bail out now.
1196 */
1197 if (unlikely(!ncsw))
1198 break;
1199
1200 /*
1201 * Was it really running after all now that we
1202 * checked with the proper locks actually held?
1203 *
1204 * Oops. Go back and try again..
1205 */
1206 if (unlikely(running)) {
1207 cpu_relax();
1208 continue;
1209 }
1210
1211 /*
1212 * It's not enough that it's not actively running,
1213 * it must be off the runqueue _entirely_, and not
1214 * preempted!
1215 *
1216 * So if it was still runnable (but just not actively
1217 * running right now), it's preempted, and we should
1218 * yield - it could be a while.
1219 */
1220 if (unlikely(on_rq)) {
1221 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1222
1223 set_current_state(TASK_UNINTERRUPTIBLE);
1224 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1225 continue;
1226 }
1227
1228 /*
1229 * Ahh, all good. It wasn't running, and it wasn't
1230 * runnable, which means that it will never become
1231 * running in the future either. We're all done!
1232 */
1233 break;
1234 }
1235
1236 return ncsw;
1237}
1238
1239/***
1240 * kick_process - kick a running thread to enter/exit the kernel
1241 * @p: the to-be-kicked thread
1242 *
1243 * Cause a process which is running on another CPU to enter
1244 * kernel-mode, without any delay. (to get signals handled.)
1245 *
1246 * NOTE: this function doesn't have to take the runqueue lock,
1247 * because all it wants to ensure is that the remote task enters
1248 * the kernel. If the IPI races and the task has been migrated
1249 * to another CPU then no harm is done and the purpose has been
1250 * achieved as well.
1251 */
1252void kick_process(struct task_struct *p)
1253{
1254 int cpu;
1255
1256 preempt_disable();
1257 cpu = task_cpu(p);
1258 if ((cpu != smp_processor_id()) && task_curr(p))
1259 smp_send_reschedule(cpu);
1260 preempt_enable();
1261}
1262EXPORT_SYMBOL_GPL(kick_process);
1263#endif /* CONFIG_SMP */
1264
1265#ifdef CONFIG_SMP
1266/*
1267 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1268 */
1269static int select_fallback_rq(int cpu, struct task_struct *p)
1270{
1271 int dest_cpu;
1272 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
1273
1274 /* Look for allowed, online CPU in same node. */
1275 for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)
1276 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1277 return dest_cpu;
1278
1279 /* Any allowed, online CPU? */
1280 dest_cpu = cpumask_any_and(tsk_cpus_allowed(p), cpu_active_mask);
1281 if (dest_cpu < nr_cpu_ids)
1282 return dest_cpu;
1283
1284 /* No more Mr. Nice Guy. */
1285 dest_cpu = cpuset_cpus_allowed_fallback(p);
1286 /*
1287 * Don't tell them about moving exiting tasks or
1288 * kernel threads (both mm NULL), since they never
1289 * leave kernel.
1290 */
1291 if (p->mm && printk_ratelimit()) {
1292 printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n",
1293 task_pid_nr(p), p->comm, cpu);
1294 }
1295
1296 return dest_cpu;
1297}
1298
1299/*
1300 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1301 */
1302static inline
1303int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
1304{
1305 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
1306
1307 /*
1308 * In order not to call set_task_cpu() on a blocking task we need
1309 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1310 * cpu.
1311 *
1312 * Since this is common to all placement strategies, this lives here.
1313 *
1314 * [ this allows ->select_task() to simply return task_cpu(p) and
1315 * not worry about this generic constraint ]
1316 */
1317 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
1318 !cpu_online(cpu)))
1319 cpu = select_fallback_rq(task_cpu(p), p);
1320
1321 return cpu;
1322}
1323
1324static void update_avg(u64 *avg, u64 sample)
1325{
1326 s64 diff = sample - *avg;
1327 *avg += diff >> 3;
1328}
1329#endif
1330
1331static void
1332ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
1333{
1334#ifdef CONFIG_SCHEDSTATS
1335 struct rq *rq = this_rq();
1336
1337#ifdef CONFIG_SMP
1338 int this_cpu = smp_processor_id();
1339
1340 if (cpu == this_cpu) {
1341 schedstat_inc(rq, ttwu_local);
1342 schedstat_inc(p, se.statistics.nr_wakeups_local);
1343 } else {
1344 struct sched_domain *sd;
1345
1346 schedstat_inc(p, se.statistics.nr_wakeups_remote);
1347 rcu_read_lock();
1348 for_each_domain(this_cpu, sd) {
1349 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1350 schedstat_inc(sd, ttwu_wake_remote);
1351 break;
1352 }
1353 }
1354 rcu_read_unlock();
1355 }
1356
1357 if (wake_flags & WF_MIGRATED)
1358 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1359
1360#endif /* CONFIG_SMP */
1361
1362 schedstat_inc(rq, ttwu_count);
1363 schedstat_inc(p, se.statistics.nr_wakeups);
1364
1365 if (wake_flags & WF_SYNC)
1366 schedstat_inc(p, se.statistics.nr_wakeups_sync);
1367
1368#endif /* CONFIG_SCHEDSTATS */
1369}
1370
1371static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1372{
1373 activate_task(rq, p, en_flags);
1374 p->on_rq = 1;
1375
1376 /* if a worker is waking up, notify workqueue */
1377 if (p->flags & PF_WQ_WORKER)
1378 wq_worker_waking_up(p, cpu_of(rq));
1379}
1380
1381/*
1382 * Mark the task runnable and perform wakeup-preemption.
1383 */
1384static void
1385ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
1386{
1387 trace_sched_wakeup(p, true);
1388 check_preempt_curr(rq, p, wake_flags);
1389
1390 p->state = TASK_RUNNING;
1391#ifdef CONFIG_SMP
1392 if (p->sched_class->task_woken)
1393 p->sched_class->task_woken(rq, p);
1394
1395 if (rq->idle_stamp) {
1396 u64 delta = rq->clock - rq->idle_stamp;
1397 u64 max = 2*sysctl_sched_migration_cost;
1398
1399 if (delta > max)
1400 rq->avg_idle = max;
1401 else
1402 update_avg(&rq->avg_idle, delta);
1403 rq->idle_stamp = 0;
1404 }
1405#endif
1406}
1407
1408static void
1409ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1410{
1411#ifdef CONFIG_SMP
1412 if (p->sched_contributes_to_load)
1413 rq->nr_uninterruptible--;
1414#endif
1415
1416 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1417 ttwu_do_wakeup(rq, p, wake_flags);
1418}
1419
1420/*
1421 * Called in case the task @p isn't fully descheduled from its runqueue,
1422 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1423 * since all we need to do is flip p->state to TASK_RUNNING, since
1424 * the task is still ->on_rq.
1425 */
1426static int ttwu_remote(struct task_struct *p, int wake_flags)
1427{
1428 struct rq *rq;
1429 int ret = 0;
1430
1431 rq = __task_rq_lock(p);
1432 if (p->on_rq) {
1433 ttwu_do_wakeup(rq, p, wake_flags);
1434 ret = 1;
1435 }
1436 __task_rq_unlock(rq);
1437
1438 return ret;
1439}
1440
1441#ifdef CONFIG_SMP
1442static void sched_ttwu_pending(void)
1443{
1444 struct rq *rq = this_rq();
1445 struct llist_node *llist = llist_del_all(&rq->wake_list);
1446 struct task_struct *p;
1447
1448 raw_spin_lock(&rq->lock);
1449
1450 while (llist) {
1451 p = llist_entry(llist, struct task_struct, wake_entry);
1452 llist = llist_next(llist);
1453 ttwu_do_activate(rq, p, 0);
1454 }
1455
1456 raw_spin_unlock(&rq->lock);
1457}
1458
1459void scheduler_ipi(void)
1460{
1461 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1462 return;
1463
1464 /*
1465 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1466 * traditionally all their work was done from the interrupt return
1467 * path. Now that we actually do some work, we need to make sure
1468 * we do call them.
1469 *
1470 * Some archs already do call them, luckily irq_enter/exit nest
1471 * properly.
1472 *
1473 * Arguably we should visit all archs and update all handlers,
1474 * however a fair share of IPIs are still resched only so this would
1475 * somewhat pessimize the simple resched case.
1476 */
1477 irq_enter();
1478 sched_ttwu_pending();
1479
1480 /*
1481 * Check if someone kicked us for doing the nohz idle load balance.
1482 */
1483 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1484 this_rq()->idle_balance = 1;
1485 raise_softirq_irqoff(SCHED_SOFTIRQ);
1486 }
1487 irq_exit();
1488}
1489
1490static void ttwu_queue_remote(struct task_struct *p, int cpu)
1491{
1492 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
1493 smp_send_reschedule(cpu);
1494}
1495
1496#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1497static int ttwu_activate_remote(struct task_struct *p, int wake_flags)
1498{
1499 struct rq *rq;
1500 int ret = 0;
1501
1502 rq = __task_rq_lock(p);
1503 if (p->on_cpu) {
1504 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1505 ttwu_do_wakeup(rq, p, wake_flags);
1506 ret = 1;
1507 }
1508 __task_rq_unlock(rq);
1509
1510 return ret;
1511
1512}
1513#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1514#endif /* CONFIG_SMP */
1515
1516static void ttwu_queue(struct task_struct *p, int cpu)
1517{
1518 struct rq *rq = cpu_rq(cpu);
1519
1520#if defined(CONFIG_SMP)
1521 if (sched_feat(TTWU_QUEUE) && cpu != smp_processor_id()) {
1522 sched_clock_cpu(cpu); /* sync clocks x-cpu */
1523 ttwu_queue_remote(p, cpu);
1524 return;
1525 }
1526#endif
1527
1528 raw_spin_lock(&rq->lock);
1529 ttwu_do_activate(rq, p, 0);
1530 raw_spin_unlock(&rq->lock);
1531}
1532
1533/**
1534 * try_to_wake_up - wake up a thread
1535 * @p: the thread to be awakened
1536 * @state: the mask of task states that can be woken
1537 * @wake_flags: wake modifier flags (WF_*)
1538 *
1539 * Put it on the run-queue if it's not already there. The "current"
1540 * thread is always on the run-queue (except when the actual
1541 * re-schedule is in progress), and as such you're allowed to do
1542 * the simpler "current->state = TASK_RUNNING" to mark yourself
1543 * runnable without the overhead of this.
1544 *
1545 * Returns %true if @p was woken up, %false if it was already running
1546 * or @state didn't match @p's state.
1547 */
1548static int
1549try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1550{
1551 unsigned long flags;
1552 int cpu, success = 0;
1553
1554 smp_wmb();
1555 raw_spin_lock_irqsave(&p->pi_lock, flags);
1556 if (!(p->state & state))
1557 goto out;
1558
1559 success = 1; /* we're going to change ->state */
1560 cpu = task_cpu(p);
1561
1562 if (p->on_rq && ttwu_remote(p, wake_flags))
1563 goto stat;
1564
1565#ifdef CONFIG_SMP
1566 /*
1567 * If the owning (remote) cpu is still in the middle of schedule() with
1568 * this task as prev, wait until its done referencing the task.
1569 */
1570 while (p->on_cpu) {
1571#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1572 /*
1573 * In case the architecture enables interrupts in
1574 * context_switch(), we cannot busy wait, since that
1575 * would lead to deadlocks when an interrupt hits and
1576 * tries to wake up @prev. So bail and do a complete
1577 * remote wakeup.
1578 */
1579 if (ttwu_activate_remote(p, wake_flags))
1580 goto stat;
1581#else
1582 cpu_relax();
1583#endif
1584 }
1585 /*
1586 * Pairs with the smp_wmb() in finish_lock_switch().
1587 */
1588 smp_rmb();
1589
1590 p->sched_contributes_to_load = !!task_contributes_to_load(p);
1591 p->state = TASK_WAKING;
1592
1593 if (p->sched_class->task_waking)
1594 p->sched_class->task_waking(p);
1595
1596 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
1597 if (task_cpu(p) != cpu) {
1598 wake_flags |= WF_MIGRATED;
1599 set_task_cpu(p, cpu);
1600 }
1601#endif /* CONFIG_SMP */
1602
1603 ttwu_queue(p, cpu);
1604stat:
1605 ttwu_stat(p, cpu, wake_flags);
1606out:
1607 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1608
1609 return success;
1610}
1611
1612/**
1613 * try_to_wake_up_local - try to wake up a local task with rq lock held
1614 * @p: the thread to be awakened
1615 *
1616 * Put @p on the run-queue if it's not already there. The caller must
1617 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1618 * the current task.
1619 */
1620static void try_to_wake_up_local(struct task_struct *p)
1621{
1622 struct rq *rq = task_rq(p);
1623
1624 BUG_ON(rq != this_rq());
1625 BUG_ON(p == current);
1626 lockdep_assert_held(&rq->lock);
1627
1628 if (!raw_spin_trylock(&p->pi_lock)) {
1629 raw_spin_unlock(&rq->lock);
1630 raw_spin_lock(&p->pi_lock);
1631 raw_spin_lock(&rq->lock);
1632 }
1633
1634 if (!(p->state & TASK_NORMAL))
1635 goto out;
1636
1637 if (!p->on_rq)
1638 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1639
1640 ttwu_do_wakeup(rq, p, 0);
1641 ttwu_stat(p, smp_processor_id(), 0);
1642out:
1643 raw_spin_unlock(&p->pi_lock);
1644}
1645
1646/**
1647 * wake_up_process - Wake up a specific process
1648 * @p: The process to be woken up.
1649 *
1650 * Attempt to wake up the nominated process and move it to the set of runnable
1651 * processes. Returns 1 if the process was woken up, 0 if it was already
1652 * running.
1653 *
1654 * It may be assumed that this function implies a write memory barrier before
1655 * changing the task state if and only if any tasks are woken up.
1656 */
1657int wake_up_process(struct task_struct *p)
1658{
1659 return try_to_wake_up(p, TASK_ALL, 0);
1660}
1661EXPORT_SYMBOL(wake_up_process);
1662
1663int wake_up_state(struct task_struct *p, unsigned int state)
1664{
1665 return try_to_wake_up(p, state, 0);
1666}
1667
1668/*
1669 * Perform scheduler related setup for a newly forked process p.
1670 * p is forked by current.
1671 *
1672 * __sched_fork() is basic setup used by init_idle() too:
1673 */
1674static void __sched_fork(struct task_struct *p)
1675{
1676 p->on_rq = 0;
1677
1678 p->se.on_rq = 0;
1679 p->se.exec_start = 0;
1680 p->se.sum_exec_runtime = 0;
1681 p->se.prev_sum_exec_runtime = 0;
1682 p->se.nr_migrations = 0;
1683 p->se.vruntime = 0;
1684 INIT_LIST_HEAD(&p->se.group_node);
1685
1686#ifdef CONFIG_SCHEDSTATS
1687 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
1688#endif
1689
1690 INIT_LIST_HEAD(&p->rt.run_list);
1691
1692#ifdef CONFIG_PREEMPT_NOTIFIERS
1693 INIT_HLIST_HEAD(&p->preempt_notifiers);
1694#endif
1695}
1696
1697/*
1698 * fork()/clone()-time setup:
1699 */
1700void sched_fork(struct task_struct *p)
1701{
1702 unsigned long flags;
1703 int cpu = get_cpu();
1704
1705 __sched_fork(p);
1706 /*
1707 * We mark the process as running here. This guarantees that
1708 * nobody will actually run it, and a signal or other external
1709 * event cannot wake it up and insert it on the runqueue either.
1710 */
1711 p->state = TASK_RUNNING;
1712
1713 /*
1714 * Make sure we do not leak PI boosting priority to the child.
1715 */
1716 p->prio = current->normal_prio;
1717
1718 /*
1719 * Revert to default priority/policy on fork if requested.
1720 */
1721 if (unlikely(p->sched_reset_on_fork)) {
1722 if (task_has_rt_policy(p)) {
1723 p->policy = SCHED_NORMAL;
1724 p->static_prio = NICE_TO_PRIO(0);
1725 p->rt_priority = 0;
1726 } else if (PRIO_TO_NICE(p->static_prio) < 0)
1727 p->static_prio = NICE_TO_PRIO(0);
1728
1729 p->prio = p->normal_prio = __normal_prio(p);
1730 set_load_weight(p);
1731
1732 /*
1733 * We don't need the reset flag anymore after the fork. It has
1734 * fulfilled its duty:
1735 */
1736 p->sched_reset_on_fork = 0;
1737 }
1738
1739 if (!rt_prio(p->prio))
1740 p->sched_class = &fair_sched_class;
1741
1742 if (p->sched_class->task_fork)
1743 p->sched_class->task_fork(p);
1744
1745 /*
1746 * The child is not yet in the pid-hash so no cgroup attach races,
1747 * and the cgroup is pinned to this child due to cgroup_fork()
1748 * is ran before sched_fork().
1749 *
1750 * Silence PROVE_RCU.
1751 */
1752 raw_spin_lock_irqsave(&p->pi_lock, flags);
1753 set_task_cpu(p, cpu);
1754 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1755
1756#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1757 if (likely(sched_info_on()))
1758 memset(&p->sched_info, 0, sizeof(p->sched_info));
1759#endif
1760#if defined(CONFIG_SMP)
1761 p->on_cpu = 0;
1762#endif
1763#ifdef CONFIG_PREEMPT_COUNT
1764 /* Want to start with kernel preemption disabled. */
1765 task_thread_info(p)->preempt_count = 1;
1766#endif
1767#ifdef CONFIG_SMP
1768 plist_node_init(&p->pushable_tasks, MAX_PRIO);
1769#endif
1770
1771 put_cpu();
1772}
1773
1774/*
1775 * wake_up_new_task - wake up a newly created task for the first time.
1776 *
1777 * This function will do some initial scheduler statistics housekeeping
1778 * that must be done for every newly created context, then puts the task
1779 * on the runqueue and wakes it.
1780 */
1781void wake_up_new_task(struct task_struct *p)
1782{
1783 unsigned long flags;
1784 struct rq *rq;
1785
1786 raw_spin_lock_irqsave(&p->pi_lock, flags);
1787#ifdef CONFIG_SMP
1788 /*
1789 * Fork balancing, do it here and not earlier because:
1790 * - cpus_allowed can change in the fork path
1791 * - any previously selected cpu might disappear through hotplug
1792 */
1793 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
1794#endif
1795
1796 rq = __task_rq_lock(p);
1797 activate_task(rq, p, 0);
1798 p->on_rq = 1;
1799 trace_sched_wakeup_new(p, true);
1800 check_preempt_curr(rq, p, WF_FORK);
1801#ifdef CONFIG_SMP
1802 if (p->sched_class->task_woken)
1803 p->sched_class->task_woken(rq, p);
1804#endif
1805 task_rq_unlock(rq, p, &flags);
1806}
1807
1808#ifdef CONFIG_PREEMPT_NOTIFIERS
1809
1810/**
1811 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1812 * @notifier: notifier struct to register
1813 */
1814void preempt_notifier_register(struct preempt_notifier *notifier)
1815{
1816 hlist_add_head(&notifier->link, &current->preempt_notifiers);
1817}
1818EXPORT_SYMBOL_GPL(preempt_notifier_register);
1819
1820/**
1821 * preempt_notifier_unregister - no longer interested in preemption notifications
1822 * @notifier: notifier struct to unregister
1823 *
1824 * This is safe to call from within a preemption notifier.
1825 */
1826void preempt_notifier_unregister(struct preempt_notifier *notifier)
1827{
1828 hlist_del(&notifier->link);
1829}
1830EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
1831
1832static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1833{
1834 struct preempt_notifier *notifier;
1835 struct hlist_node *node;
1836
1837 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1838 notifier->ops->sched_in(notifier, raw_smp_processor_id());
1839}
1840
1841static void
1842fire_sched_out_preempt_notifiers(struct task_struct *curr,
1843 struct task_struct *next)
1844{
1845 struct preempt_notifier *notifier;
1846 struct hlist_node *node;
1847
1848 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1849 notifier->ops->sched_out(notifier, next);
1850}
1851
1852#else /* !CONFIG_PREEMPT_NOTIFIERS */
1853
1854static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1855{
1856}
1857
1858static void
1859fire_sched_out_preempt_notifiers(struct task_struct *curr,
1860 struct task_struct *next)
1861{
1862}
1863
1864#endif /* CONFIG_PREEMPT_NOTIFIERS */
1865
1866/**
1867 * prepare_task_switch - prepare to switch tasks
1868 * @rq: the runqueue preparing to switch
1869 * @prev: the current task that is being switched out
1870 * @next: the task we are going to switch to.
1871 *
1872 * This is called with the rq lock held and interrupts off. It must
1873 * be paired with a subsequent finish_task_switch after the context
1874 * switch.
1875 *
1876 * prepare_task_switch sets up locking and calls architecture specific
1877 * hooks.
1878 */
1879static inline void
1880prepare_task_switch(struct rq *rq, struct task_struct *prev,
1881 struct task_struct *next)
1882{
1883 sched_info_switch(prev, next);
1884 perf_event_task_sched_out(prev, next);
1885 fire_sched_out_preempt_notifiers(prev, next);
1886 prepare_lock_switch(rq, next);
1887 prepare_arch_switch(next);
1888 trace_sched_switch(prev, next);
1889}
1890
1891/**
1892 * finish_task_switch - clean up after a task-switch
1893 * @rq: runqueue associated with task-switch
1894 * @prev: the thread we just switched away from.
1895 *
1896 * finish_task_switch must be called after the context switch, paired
1897 * with a prepare_task_switch call before the context switch.
1898 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1899 * and do any other architecture-specific cleanup actions.
1900 *
1901 * Note that we may have delayed dropping an mm in context_switch(). If
1902 * so, we finish that here outside of the runqueue lock. (Doing it
1903 * with the lock held can cause deadlocks; see schedule() for
1904 * details.)
1905 */
1906static void finish_task_switch(struct rq *rq, struct task_struct *prev)
1907 __releases(rq->lock)
1908{
1909 struct mm_struct *mm = rq->prev_mm;
1910 long prev_state;
1911
1912 rq->prev_mm = NULL;
1913
1914 /*
1915 * A task struct has one reference for the use as "current".
1916 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1917 * schedule one last time. The schedule call will never return, and
1918 * the scheduled task must drop that reference.
1919 * The test for TASK_DEAD must occur while the runqueue locks are
1920 * still held, otherwise prev could be scheduled on another cpu, die
1921 * there before we look at prev->state, and then the reference would
1922 * be dropped twice.
1923 * Manfred Spraul <manfred@colorfullife.com>
1924 */
1925 prev_state = prev->state;
1926 finish_arch_switch(prev);
1927#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1928 local_irq_disable();
1929#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1930 perf_event_task_sched_in(prev, current);
1931#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1932 local_irq_enable();
1933#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1934 finish_lock_switch(rq, prev);
1935
1936 fire_sched_in_preempt_notifiers(current);
1937 if (mm)
1938 mmdrop(mm);
1939 if (unlikely(prev_state == TASK_DEAD)) {
1940 /*
1941 * Remove function-return probe instances associated with this
1942 * task and put them back on the free list.
1943 */
1944 kprobe_flush_task(prev);
1945 put_task_struct(prev);
1946 }
1947}
1948
1949#ifdef CONFIG_SMP
1950
1951/* assumes rq->lock is held */
1952static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
1953{
1954 if (prev->sched_class->pre_schedule)
1955 prev->sched_class->pre_schedule(rq, prev);
1956}
1957
1958/* rq->lock is NOT held, but preemption is disabled */
1959static inline void post_schedule(struct rq *rq)
1960{
1961 if (rq->post_schedule) {
1962 unsigned long flags;
1963
1964 raw_spin_lock_irqsave(&rq->lock, flags);
1965 if (rq->curr->sched_class->post_schedule)
1966 rq->curr->sched_class->post_schedule(rq);
1967 raw_spin_unlock_irqrestore(&rq->lock, flags);
1968
1969 rq->post_schedule = 0;
1970 }
1971}
1972
1973#else
1974
1975static inline void pre_schedule(struct rq *rq, struct task_struct *p)
1976{
1977}
1978
1979static inline void post_schedule(struct rq *rq)
1980{
1981}
1982
1983#endif
1984
1985/**
1986 * schedule_tail - first thing a freshly forked thread must call.
1987 * @prev: the thread we just switched away from.
1988 */
1989asmlinkage void schedule_tail(struct task_struct *prev)
1990 __releases(rq->lock)
1991{
1992 struct rq *rq = this_rq();
1993
1994 finish_task_switch(rq, prev);
1995
1996 /*
1997 * FIXME: do we need to worry about rq being invalidated by the
1998 * task_switch?
1999 */
2000 post_schedule(rq);
2001
2002#ifdef __ARCH_WANT_UNLOCKED_CTXSW
2003 /* In this case, finish_task_switch does not reenable preemption */
2004 preempt_enable();
2005#endif
2006 if (current->set_child_tid)
2007 put_user(task_pid_vnr(current), current->set_child_tid);
2008}
2009
2010/*
2011 * context_switch - switch to the new MM and the new
2012 * thread's register state.
2013 */
2014static inline void
2015context_switch(struct rq *rq, struct task_struct *prev,
2016 struct task_struct *next)
2017{
2018 struct mm_struct *mm, *oldmm;
2019
2020 prepare_task_switch(rq, prev, next);
2021
2022 mm = next->mm;
2023 oldmm = prev->active_mm;
2024 /*
2025 * For paravirt, this is coupled with an exit in switch_to to
2026 * combine the page table reload and the switch backend into
2027 * one hypercall.
2028 */
2029 arch_start_context_switch(prev);
2030
2031 if (!mm) {
2032 next->active_mm = oldmm;
2033 atomic_inc(&oldmm->mm_count);
2034 enter_lazy_tlb(oldmm, next);
2035 } else
2036 switch_mm(oldmm, mm, next);
2037
2038 if (!prev->mm) {
2039 prev->active_mm = NULL;
2040 rq->prev_mm = oldmm;
2041 }
2042 /*
2043 * Since the runqueue lock will be released by the next
2044 * task (which is an invalid locking op but in the case
2045 * of the scheduler it's an obvious special-case), so we
2046 * do an early lockdep release here:
2047 */
2048#ifndef __ARCH_WANT_UNLOCKED_CTXSW
2049 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2050#endif
2051
2052 /* Here we just switch the register state and the stack. */
2053 switch_to(prev, next, prev);
2054
2055 barrier();
2056 /*
2057 * this_rq must be evaluated again because prev may have moved
2058 * CPUs since it called schedule(), thus the 'rq' on its stack
2059 * frame will be invalid.
2060 */
2061 finish_task_switch(this_rq(), prev);
2062}
2063
2064/*
2065 * nr_running, nr_uninterruptible and nr_context_switches:
2066 *
2067 * externally visible scheduler statistics: current number of runnable
2068 * threads, current number of uninterruptible-sleeping threads, total
2069 * number of context switches performed since bootup.
2070 */
2071unsigned long nr_running(void)
2072{
2073 unsigned long i, sum = 0;
2074
2075 for_each_online_cpu(i)
2076 sum += cpu_rq(i)->nr_running;
2077
2078 return sum;
2079}
2080
2081unsigned long nr_uninterruptible(void)
2082{
2083 unsigned long i, sum = 0;
2084
2085 for_each_possible_cpu(i)
2086 sum += cpu_rq(i)->nr_uninterruptible;
2087
2088 /*
2089 * Since we read the counters lockless, it might be slightly
2090 * inaccurate. Do not allow it to go below zero though:
2091 */
2092 if (unlikely((long)sum < 0))
2093 sum = 0;
2094
2095 return sum;
2096}
2097
2098unsigned long long nr_context_switches(void)
2099{
2100 int i;
2101 unsigned long long sum = 0;
2102
2103 for_each_possible_cpu(i)
2104 sum += cpu_rq(i)->nr_switches;
2105
2106 return sum;
2107}
2108
2109unsigned long nr_iowait(void)
2110{
2111 unsigned long i, sum = 0;
2112
2113 for_each_possible_cpu(i)
2114 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2115
2116 return sum;
2117}
2118
2119unsigned long nr_iowait_cpu(int cpu)
2120{
2121 struct rq *this = cpu_rq(cpu);
2122 return atomic_read(&this->nr_iowait);
2123}
2124
2125unsigned long this_cpu_load(void)
2126{
2127 struct rq *this = this_rq();
2128 return this->cpu_load[0];
2129}
2130
2131
2132/* Variables and functions for calc_load */
2133static atomic_long_t calc_load_tasks;
2134static unsigned long calc_load_update;
2135unsigned long avenrun[3];
2136EXPORT_SYMBOL(avenrun);
2137
2138static long calc_load_fold_active(struct rq *this_rq)
2139{
2140 long nr_active, delta = 0;
2141
2142 nr_active = this_rq->nr_running;
2143 nr_active += (long) this_rq->nr_uninterruptible;
2144
2145 if (nr_active != this_rq->calc_load_active) {
2146 delta = nr_active - this_rq->calc_load_active;
2147 this_rq->calc_load_active = nr_active;
2148 }
2149
2150 return delta;
2151}
2152
2153static unsigned long
2154calc_load(unsigned long load, unsigned long exp, unsigned long active)
2155{
2156 load *= exp;
2157 load += active * (FIXED_1 - exp);
2158 load += 1UL << (FSHIFT - 1);
2159 return load >> FSHIFT;
2160}
2161
2162#ifdef CONFIG_NO_HZ
2163/*
2164 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2165 *
2166 * When making the ILB scale, we should try to pull this in as well.
2167 */
2168static atomic_long_t calc_load_tasks_idle;
2169
2170void calc_load_account_idle(struct rq *this_rq)
2171{
2172 long delta;
2173
2174 delta = calc_load_fold_active(this_rq);
2175 if (delta)
2176 atomic_long_add(delta, &calc_load_tasks_idle);
2177}
2178
2179static long calc_load_fold_idle(void)
2180{
2181 long delta = 0;
2182
2183 /*
2184 * Its got a race, we don't care...
2185 */
2186 if (atomic_long_read(&calc_load_tasks_idle))
2187 delta = atomic_long_xchg(&calc_load_tasks_idle, 0);
2188
2189 return delta;
2190}
2191
2192/**
2193 * fixed_power_int - compute: x^n, in O(log n) time
2194 *
2195 * @x: base of the power
2196 * @frac_bits: fractional bits of @x
2197 * @n: power to raise @x to.
2198 *
2199 * By exploiting the relation between the definition of the natural power
2200 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2201 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2202 * (where: n_i \elem {0, 1}, the binary vector representing n),
2203 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2204 * of course trivially computable in O(log_2 n), the length of our binary
2205 * vector.
2206 */
2207static unsigned long
2208fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
2209{
2210 unsigned long result = 1UL << frac_bits;
2211
2212 if (n) for (;;) {
2213 if (n & 1) {
2214 result *= x;
2215 result += 1UL << (frac_bits - 1);
2216 result >>= frac_bits;
2217 }
2218 n >>= 1;
2219 if (!n)
2220 break;
2221 x *= x;
2222 x += 1UL << (frac_bits - 1);
2223 x >>= frac_bits;
2224 }
2225
2226 return result;
2227}
2228
2229/*
2230 * a1 = a0 * e + a * (1 - e)
2231 *
2232 * a2 = a1 * e + a * (1 - e)
2233 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2234 * = a0 * e^2 + a * (1 - e) * (1 + e)
2235 *
2236 * a3 = a2 * e + a * (1 - e)
2237 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2238 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2239 *
2240 * ...
2241 *
2242 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2243 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2244 * = a0 * e^n + a * (1 - e^n)
2245 *
2246 * [1] application of the geometric series:
2247 *
2248 * n 1 - x^(n+1)
2249 * S_n := \Sum x^i = -------------
2250 * i=0 1 - x
2251 */
2252static unsigned long
2253calc_load_n(unsigned long load, unsigned long exp,
2254 unsigned long active, unsigned int n)
2255{
2256
2257 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
2258}
2259
2260/*
2261 * NO_HZ can leave us missing all per-cpu ticks calling
2262 * calc_load_account_active(), but since an idle CPU folds its delta into
2263 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2264 * in the pending idle delta if our idle period crossed a load cycle boundary.
2265 *
2266 * Once we've updated the global active value, we need to apply the exponential
2267 * weights adjusted to the number of cycles missed.
2268 */
2269static void calc_global_nohz(unsigned long ticks)
2270{
2271 long delta, active, n;
2272
2273 if (time_before(jiffies, calc_load_update))
2274 return;
2275
2276 /*
2277 * If we crossed a calc_load_update boundary, make sure to fold
2278 * any pending idle changes, the respective CPUs might have
2279 * missed the tick driven calc_load_account_active() update
2280 * due to NO_HZ.
2281 */
2282 delta = calc_load_fold_idle();
2283 if (delta)
2284 atomic_long_add(delta, &calc_load_tasks);
2285
2286 /*
2287 * If we were idle for multiple load cycles, apply them.
2288 */
2289 if (ticks >= LOAD_FREQ) {
2290 n = ticks / LOAD_FREQ;
2291
2292 active = atomic_long_read(&calc_load_tasks);
2293 active = active > 0 ? active * FIXED_1 : 0;
2294
2295 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
2296 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
2297 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
2298
2299 calc_load_update += n * LOAD_FREQ;
2300 }
2301
2302 /*
2303 * Its possible the remainder of the above division also crosses
2304 * a LOAD_FREQ period, the regular check in calc_global_load()
2305 * which comes after this will take care of that.
2306 *
2307 * Consider us being 11 ticks before a cycle completion, and us
2308 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
2309 * age us 4 cycles, and the test in calc_global_load() will
2310 * pick up the final one.
2311 */
2312}
2313#else
2314void calc_load_account_idle(struct rq *this_rq)
2315{
2316}
2317
2318static inline long calc_load_fold_idle(void)
2319{
2320 return 0;
2321}
2322
2323static void calc_global_nohz(unsigned long ticks)
2324{
2325}
2326#endif
2327
2328/**
2329 * get_avenrun - get the load average array
2330 * @loads: pointer to dest load array
2331 * @offset: offset to add
2332 * @shift: shift count to shift the result left
2333 *
2334 * These values are estimates at best, so no need for locking.
2335 */
2336void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
2337{
2338 loads[0] = (avenrun[0] + offset) << shift;
2339 loads[1] = (avenrun[1] + offset) << shift;
2340 loads[2] = (avenrun[2] + offset) << shift;
2341}
2342
2343/*
2344 * calc_load - update the avenrun load estimates 10 ticks after the
2345 * CPUs have updated calc_load_tasks.
2346 */
2347void calc_global_load(unsigned long ticks)
2348{
2349 long active;
2350
2351 calc_global_nohz(ticks);
2352
2353 if (time_before(jiffies, calc_load_update + 10))
2354 return;
2355
2356 active = atomic_long_read(&calc_load_tasks);
2357 active = active > 0 ? active * FIXED_1 : 0;
2358
2359 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
2360 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
2361 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
2362
2363 calc_load_update += LOAD_FREQ;
2364}
2365
2366/*
2367 * Called from update_cpu_load() to periodically update this CPU's
2368 * active count.
2369 */
2370static void calc_load_account_active(struct rq *this_rq)
2371{
2372 long delta;
2373
2374 if (time_before(jiffies, this_rq->calc_load_update))
2375 return;
2376
2377 delta = calc_load_fold_active(this_rq);
2378 delta += calc_load_fold_idle();
2379 if (delta)
2380 atomic_long_add(delta, &calc_load_tasks);
2381
2382 this_rq->calc_load_update += LOAD_FREQ;
2383}
2384
2385/*
2386 * The exact cpuload at various idx values, calculated at every tick would be
2387 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2388 *
2389 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2390 * on nth tick when cpu may be busy, then we have:
2391 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2392 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2393 *
2394 * decay_load_missed() below does efficient calculation of
2395 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2396 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2397 *
2398 * The calculation is approximated on a 128 point scale.
2399 * degrade_zero_ticks is the number of ticks after which load at any
2400 * particular idx is approximated to be zero.
2401 * degrade_factor is a precomputed table, a row for each load idx.
2402 * Each column corresponds to degradation factor for a power of two ticks,
2403 * based on 128 point scale.
2404 * Example:
2405 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2406 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2407 *
2408 * With this power of 2 load factors, we can degrade the load n times
2409 * by looking at 1 bits in n and doing as many mult/shift instead of
2410 * n mult/shifts needed by the exact degradation.
2411 */
2412#define DEGRADE_SHIFT 7
2413static const unsigned char
2414 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
2415static const unsigned char
2416 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
2417 {0, 0, 0, 0, 0, 0, 0, 0},
2418 {64, 32, 8, 0, 0, 0, 0, 0},
2419 {96, 72, 40, 12, 1, 0, 0},
2420 {112, 98, 75, 43, 15, 1, 0},
2421 {120, 112, 98, 76, 45, 16, 2} };
2422
2423/*
2424 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2425 * would be when CPU is idle and so we just decay the old load without
2426 * adding any new load.
2427 */
2428static unsigned long
2429decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
2430{
2431 int j = 0;
2432
2433 if (!missed_updates)
2434 return load;
2435
2436 if (missed_updates >= degrade_zero_ticks[idx])
2437 return 0;
2438
2439 if (idx == 1)
2440 return load >> missed_updates;
2441
2442 while (missed_updates) {
2443 if (missed_updates % 2)
2444 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
2445
2446 missed_updates >>= 1;
2447 j++;
2448 }
2449 return load;
2450}
2451
2452/*
2453 * Update rq->cpu_load[] statistics. This function is usually called every
2454 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2455 * every tick. We fix it up based on jiffies.
2456 */
2457void update_cpu_load(struct rq *this_rq)
2458{
2459 unsigned long this_load = this_rq->load.weight;
2460 unsigned long curr_jiffies = jiffies;
2461 unsigned long pending_updates;
2462 int i, scale;
2463
2464 this_rq->nr_load_updates++;
2465
2466 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
2467 if (curr_jiffies == this_rq->last_load_update_tick)
2468 return;
2469
2470 pending_updates = curr_jiffies - this_rq->last_load_update_tick;
2471 this_rq->last_load_update_tick = curr_jiffies;
2472
2473 /* Update our load: */
2474 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
2475 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2476 unsigned long old_load, new_load;
2477
2478 /* scale is effectively 1 << i now, and >> i divides by scale */
2479
2480 old_load = this_rq->cpu_load[i];
2481 old_load = decay_load_missed(old_load, pending_updates - 1, i);
2482 new_load = this_load;
2483 /*
2484 * Round up the averaging division if load is increasing. This
2485 * prevents us from getting stuck on 9 if the load is 10, for
2486 * example.
2487 */
2488 if (new_load > old_load)
2489 new_load += scale - 1;
2490
2491 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
2492 }
2493
2494 sched_avg_update(this_rq);
2495}
2496
2497static void update_cpu_load_active(struct rq *this_rq)
2498{
2499 update_cpu_load(this_rq);
2500
2501 calc_load_account_active(this_rq);
2502}
2503
2504#ifdef CONFIG_SMP
2505
2506/*
2507 * sched_exec - execve() is a valuable balancing opportunity, because at
2508 * this point the task has the smallest effective memory and cache footprint.
2509 */
2510void sched_exec(void)
2511{
2512 struct task_struct *p = current;
2513 unsigned long flags;
2514 int dest_cpu;
2515
2516 raw_spin_lock_irqsave(&p->pi_lock, flags);
2517 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
2518 if (dest_cpu == smp_processor_id())
2519 goto unlock;
2520
2521 if (likely(cpu_active(dest_cpu))) {
2522 struct migration_arg arg = { p, dest_cpu };
2523
2524 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2525 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
2526 return;
2527 }
2528unlock:
2529 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2530}
2531
2532#endif
2533
2534DEFINE_PER_CPU(struct kernel_stat, kstat);
2535DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
2536
2537EXPORT_PER_CPU_SYMBOL(kstat);
2538EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
2539
2540/*
2541 * Return any ns on the sched_clock that have not yet been accounted in
2542 * @p in case that task is currently running.
2543 *
2544 * Called with task_rq_lock() held on @rq.
2545 */
2546static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
2547{
2548 u64 ns = 0;
2549
2550 if (task_current(rq, p)) {
2551 update_rq_clock(rq);
2552 ns = rq->clock_task - p->se.exec_start;
2553 if ((s64)ns < 0)
2554 ns = 0;
2555 }
2556
2557 return ns;
2558}
2559
2560unsigned long long task_delta_exec(struct task_struct *p)
2561{
2562 unsigned long flags;
2563 struct rq *rq;
2564 u64 ns = 0;
2565
2566 rq = task_rq_lock(p, &flags);
2567 ns = do_task_delta_exec(p, rq);
2568 task_rq_unlock(rq, p, &flags);
2569
2570 return ns;
2571}
2572
2573/*
2574 * Return accounted runtime for the task.
2575 * In case the task is currently running, return the runtime plus current's
2576 * pending runtime that have not been accounted yet.
2577 */
2578unsigned long long task_sched_runtime(struct task_struct *p)
2579{
2580 unsigned long flags;
2581 struct rq *rq;
2582 u64 ns = 0;
2583
2584 rq = task_rq_lock(p, &flags);
2585 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
2586 task_rq_unlock(rq, p, &flags);
2587
2588 return ns;
2589}
2590
2591#ifdef CONFIG_CGROUP_CPUACCT
2592struct cgroup_subsys cpuacct_subsys;
2593struct cpuacct root_cpuacct;
2594#endif
2595
2596static inline void task_group_account_field(struct task_struct *p, int index,
2597 u64 tmp)
2598{
2599#ifdef CONFIG_CGROUP_CPUACCT
2600 struct kernel_cpustat *kcpustat;
2601 struct cpuacct *ca;
2602#endif
2603 /*
2604 * Since all updates are sure to touch the root cgroup, we
2605 * get ourselves ahead and touch it first. If the root cgroup
2606 * is the only cgroup, then nothing else should be necessary.
2607 *
2608 */
2609 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
2610
2611#ifdef CONFIG_CGROUP_CPUACCT
2612 if (unlikely(!cpuacct_subsys.active))
2613 return;
2614
2615 rcu_read_lock();
2616 ca = task_ca(p);
2617 while (ca && (ca != &root_cpuacct)) {
2618 kcpustat = this_cpu_ptr(ca->cpustat);
2619 kcpustat->cpustat[index] += tmp;
2620 ca = parent_ca(ca);
2621 }
2622 rcu_read_unlock();
2623#endif
2624}
2625
2626
2627/*
2628 * Account user cpu time to a process.
2629 * @p: the process that the cpu time gets accounted to
2630 * @cputime: the cpu time spent in user space since the last update
2631 * @cputime_scaled: cputime scaled by cpu frequency
2632 */
2633void account_user_time(struct task_struct *p, cputime_t cputime,
2634 cputime_t cputime_scaled)
2635{
2636 int index;
2637
2638 /* Add user time to process. */
2639 p->utime += cputime;
2640 p->utimescaled += cputime_scaled;
2641 account_group_user_time(p, cputime);
2642
2643 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
2644
2645 /* Add user time to cpustat. */
2646 task_group_account_field(p, index, (__force u64) cputime);
2647
2648 /* Account for user time used */
2649 acct_update_integrals(p);
2650}
2651
2652/*
2653 * Account guest cpu time to a process.
2654 * @p: the process that the cpu time gets accounted to
2655 * @cputime: the cpu time spent in virtual machine since the last update
2656 * @cputime_scaled: cputime scaled by cpu frequency
2657 */
2658static void account_guest_time(struct task_struct *p, cputime_t cputime,
2659 cputime_t cputime_scaled)
2660{
2661 u64 *cpustat = kcpustat_this_cpu->cpustat;
2662
2663 /* Add guest time to process. */
2664 p->utime += cputime;
2665 p->utimescaled += cputime_scaled;
2666 account_group_user_time(p, cputime);
2667 p->gtime += cputime;
2668
2669 /* Add guest time to cpustat. */
2670 if (TASK_NICE(p) > 0) {
2671 cpustat[CPUTIME_NICE] += (__force u64) cputime;
2672 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
2673 } else {
2674 cpustat[CPUTIME_USER] += (__force u64) cputime;
2675 cpustat[CPUTIME_GUEST] += (__force u64) cputime;
2676 }
2677}
2678
2679/*
2680 * Account system cpu time to a process and desired cpustat field
2681 * @p: the process that the cpu time gets accounted to
2682 * @cputime: the cpu time spent in kernel space since the last update
2683 * @cputime_scaled: cputime scaled by cpu frequency
2684 * @target_cputime64: pointer to cpustat field that has to be updated
2685 */
2686static inline
2687void __account_system_time(struct task_struct *p, cputime_t cputime,
2688 cputime_t cputime_scaled, int index)
2689{
2690 /* Add system time to process. */
2691 p->stime += cputime;
2692 p->stimescaled += cputime_scaled;
2693 account_group_system_time(p, cputime);
2694
2695 /* Add system time to cpustat. */
2696 task_group_account_field(p, index, (__force u64) cputime);
2697
2698 /* Account for system time used */
2699 acct_update_integrals(p);
2700}
2701
2702/*
2703 * Account system cpu time to a process.
2704 * @p: the process that the cpu time gets accounted to
2705 * @hardirq_offset: the offset to subtract from hardirq_count()
2706 * @cputime: the cpu time spent in kernel space since the last update
2707 * @cputime_scaled: cputime scaled by cpu frequency
2708 */
2709void account_system_time(struct task_struct *p, int hardirq_offset,
2710 cputime_t cputime, cputime_t cputime_scaled)
2711{
2712 int index;
2713
2714 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
2715 account_guest_time(p, cputime, cputime_scaled);
2716 return;
2717 }
2718
2719 if (hardirq_count() - hardirq_offset)
2720 index = CPUTIME_IRQ;
2721 else if (in_serving_softirq())
2722 index = CPUTIME_SOFTIRQ;
2723 else
2724 index = CPUTIME_SYSTEM;
2725
2726 __account_system_time(p, cputime, cputime_scaled, index);
2727}
2728
2729/*
2730 * Account for involuntary wait time.
2731 * @cputime: the cpu time spent in involuntary wait
2732 */
2733void account_steal_time(cputime_t cputime)
2734{
2735 u64 *cpustat = kcpustat_this_cpu->cpustat;
2736
2737 cpustat[CPUTIME_STEAL] += (__force u64) cputime;
2738}
2739
2740/*
2741 * Account for idle time.
2742 * @cputime: the cpu time spent in idle wait
2743 */
2744void account_idle_time(cputime_t cputime)
2745{
2746 u64 *cpustat = kcpustat_this_cpu->cpustat;
2747 struct rq *rq = this_rq();
2748
2749 if (atomic_read(&rq->nr_iowait) > 0)
2750 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
2751 else
2752 cpustat[CPUTIME_IDLE] += (__force u64) cputime;
2753}
2754
2755static __always_inline bool steal_account_process_tick(void)
2756{
2757#ifdef CONFIG_PARAVIRT
2758 if (static_branch(&paravirt_steal_enabled)) {
2759 u64 steal, st = 0;
2760
2761 steal = paravirt_steal_clock(smp_processor_id());
2762 steal -= this_rq()->prev_steal_time;
2763
2764 st = steal_ticks(steal);
2765 this_rq()->prev_steal_time += st * TICK_NSEC;
2766
2767 account_steal_time(st);
2768 return st;
2769 }
2770#endif
2771 return false;
2772}
2773
2774#ifndef CONFIG_VIRT_CPU_ACCOUNTING
2775
2776#ifdef CONFIG_IRQ_TIME_ACCOUNTING
2777/*
2778 * Account a tick to a process and cpustat
2779 * @p: the process that the cpu time gets accounted to
2780 * @user_tick: is the tick from userspace
2781 * @rq: the pointer to rq
2782 *
2783 * Tick demultiplexing follows the order
2784 * - pending hardirq update
2785 * - pending softirq update
2786 * - user_time
2787 * - idle_time
2788 * - system time
2789 * - check for guest_time
2790 * - else account as system_time
2791 *
2792 * Check for hardirq is done both for system and user time as there is
2793 * no timer going off while we are on hardirq and hence we may never get an
2794 * opportunity to update it solely in system time.
2795 * p->stime and friends are only updated on system time and not on irq
2796 * softirq as those do not count in task exec_runtime any more.
2797 */
2798static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
2799 struct rq *rq)
2800{
2801 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2802 u64 *cpustat = kcpustat_this_cpu->cpustat;
2803
2804 if (steal_account_process_tick())
2805 return;
2806
2807 if (irqtime_account_hi_update()) {
2808 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
2809 } else if (irqtime_account_si_update()) {
2810 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
2811 } else if (this_cpu_ksoftirqd() == p) {
2812 /*
2813 * ksoftirqd time do not get accounted in cpu_softirq_time.
2814 * So, we have to handle it separately here.
2815 * Also, p->stime needs to be updated for ksoftirqd.
2816 */
2817 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2818 CPUTIME_SOFTIRQ);
2819 } else if (user_tick) {
2820 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
2821 } else if (p == rq->idle) {
2822 account_idle_time(cputime_one_jiffy);
2823 } else if (p->flags & PF_VCPU) { /* System time or guest time */
2824 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
2825 } else {
2826 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2827 CPUTIME_SYSTEM);
2828 }
2829}
2830
2831static void irqtime_account_idle_ticks(int ticks)
2832{
2833 int i;
2834 struct rq *rq = this_rq();
2835
2836 for (i = 0; i < ticks; i++)
2837 irqtime_account_process_tick(current, 0, rq);
2838}
2839#else /* CONFIG_IRQ_TIME_ACCOUNTING */
2840static void irqtime_account_idle_ticks(int ticks) {}
2841static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
2842 struct rq *rq) {}
2843#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2844
2845/*
2846 * Account a single tick of cpu time.
2847 * @p: the process that the cpu time gets accounted to
2848 * @user_tick: indicates if the tick is a user or a system tick
2849 */
2850void account_process_tick(struct task_struct *p, int user_tick)
2851{
2852 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2853 struct rq *rq = this_rq();
2854
2855 if (sched_clock_irqtime) {
2856 irqtime_account_process_tick(p, user_tick, rq);
2857 return;
2858 }
2859
2860 if (steal_account_process_tick())
2861 return;
2862
2863 if (user_tick)
2864 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
2865 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
2866 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
2867 one_jiffy_scaled);
2868 else
2869 account_idle_time(cputime_one_jiffy);
2870}
2871
2872/*
2873 * Account multiple ticks of steal time.
2874 * @p: the process from which the cpu time has been stolen
2875 * @ticks: number of stolen ticks
2876 */
2877void account_steal_ticks(unsigned long ticks)
2878{
2879 account_steal_time(jiffies_to_cputime(ticks));
2880}
2881
2882/*
2883 * Account multiple ticks of idle time.
2884 * @ticks: number of stolen ticks
2885 */
2886void account_idle_ticks(unsigned long ticks)
2887{
2888
2889 if (sched_clock_irqtime) {
2890 irqtime_account_idle_ticks(ticks);
2891 return;
2892 }
2893
2894 account_idle_time(jiffies_to_cputime(ticks));
2895}
2896
2897#endif
2898
2899/*
2900 * Use precise platform statistics if available:
2901 */
2902#ifdef CONFIG_VIRT_CPU_ACCOUNTING
2903void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2904{
2905 *ut = p->utime;
2906 *st = p->stime;
2907}
2908
2909void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2910{
2911 struct task_cputime cputime;
2912
2913 thread_group_cputime(p, &cputime);
2914
2915 *ut = cputime.utime;
2916 *st = cputime.stime;
2917}
2918#else
2919
2920#ifndef nsecs_to_cputime
2921# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
2922#endif
2923
2924void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2925{
2926 cputime_t rtime, utime = p->utime, total = utime + p->stime;
2927
2928 /*
2929 * Use CFS's precise accounting:
2930 */
2931 rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
2932
2933 if (total) {
2934 u64 temp = (__force u64) rtime;
2935
2936 temp *= (__force u64) utime;
2937 do_div(temp, (__force u32) total);
2938 utime = (__force cputime_t) temp;
2939 } else
2940 utime = rtime;
2941
2942 /*
2943 * Compare with previous values, to keep monotonicity:
2944 */
2945 p->prev_utime = max(p->prev_utime, utime);
2946 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
2947
2948 *ut = p->prev_utime;
2949 *st = p->prev_stime;
2950}
2951
2952/*
2953 * Must be called with siglock held.
2954 */
2955void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2956{
2957 struct signal_struct *sig = p->signal;
2958 struct task_cputime cputime;
2959 cputime_t rtime, utime, total;
2960
2961 thread_group_cputime(p, &cputime);
2962
2963 total = cputime.utime + cputime.stime;
2964 rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
2965
2966 if (total) {
2967 u64 temp = (__force u64) rtime;
2968
2969 temp *= (__force u64) cputime.utime;
2970 do_div(temp, (__force u32) total);
2971 utime = (__force cputime_t) temp;
2972 } else
2973 utime = rtime;
2974
2975 sig->prev_utime = max(sig->prev_utime, utime);
2976 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
2977
2978 *ut = sig->prev_utime;
2979 *st = sig->prev_stime;
2980}
2981#endif
2982
2983/*
2984 * This function gets called by the timer code, with HZ frequency.
2985 * We call it with interrupts disabled.
2986 */
2987void scheduler_tick(void)
2988{
2989 int cpu = smp_processor_id();
2990 struct rq *rq = cpu_rq(cpu);
2991 struct task_struct *curr = rq->curr;
2992
2993 sched_clock_tick();
2994
2995 raw_spin_lock(&rq->lock);
2996 update_rq_clock(rq);
2997 update_cpu_load_active(rq);
2998 curr->sched_class->task_tick(rq, curr, 0);
2999 raw_spin_unlock(&rq->lock);
3000
3001 perf_event_task_tick();
3002
3003#ifdef CONFIG_SMP
3004 rq->idle_balance = idle_cpu(cpu);
3005 trigger_load_balance(rq, cpu);
3006#endif
3007}
3008
3009notrace unsigned long get_parent_ip(unsigned long addr)
3010{
3011 if (in_lock_functions(addr)) {
3012 addr = CALLER_ADDR2;
3013 if (in_lock_functions(addr))
3014 addr = CALLER_ADDR3;
3015 }
3016 return addr;
3017}
3018
3019#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3020 defined(CONFIG_PREEMPT_TRACER))
3021
3022void __kprobes add_preempt_count(int val)
3023{
3024#ifdef CONFIG_DEBUG_PREEMPT
3025 /*
3026 * Underflow?
3027 */
3028 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3029 return;
3030#endif
3031 preempt_count() += val;
3032#ifdef CONFIG_DEBUG_PREEMPT
3033 /*
3034 * Spinlock count overflowing soon?
3035 */
3036 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3037 PREEMPT_MASK - 10);
3038#endif
3039 if (preempt_count() == val)
3040 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3041}
3042EXPORT_SYMBOL(add_preempt_count);
3043
3044void __kprobes sub_preempt_count(int val)
3045{
3046#ifdef CONFIG_DEBUG_PREEMPT
3047 /*
3048 * Underflow?
3049 */
3050 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3051 return;
3052 /*
3053 * Is the spinlock portion underflowing?
3054 */
3055 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3056 !(preempt_count() & PREEMPT_MASK)))
3057 return;
3058#endif
3059
3060 if (preempt_count() == val)
3061 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3062 preempt_count() -= val;
3063}
3064EXPORT_SYMBOL(sub_preempt_count);
3065
3066#endif
3067
3068/*
3069 * Print scheduling while atomic bug:
3070 */
3071static noinline void __schedule_bug(struct task_struct *prev)
3072{
3073 struct pt_regs *regs = get_irq_regs();
3074
3075 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3076 prev->comm, prev->pid, preempt_count());
3077
3078 debug_show_held_locks(prev);
3079 print_modules();
3080 if (irqs_disabled())
3081 print_irqtrace_events(prev);
3082
3083 if (regs)
3084 show_regs(regs);
3085 else
3086 dump_stack();
3087}
3088
3089/*
3090 * Various schedule()-time debugging checks and statistics:
3091 */
3092static inline void schedule_debug(struct task_struct *prev)
3093{
3094 /*
3095 * Test if we are atomic. Since do_exit() needs to call into
3096 * schedule() atomically, we ignore that path for now.
3097 * Otherwise, whine if we are scheduling when we should not be.
3098 */
3099 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
3100 __schedule_bug(prev);
3101 rcu_sleep_check();
3102
3103 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3104
3105 schedstat_inc(this_rq(), sched_count);
3106}
3107
3108static void put_prev_task(struct rq *rq, struct task_struct *prev)
3109{
3110 if (prev->on_rq || rq->skip_clock_update < 0)
3111 update_rq_clock(rq);
3112 prev->sched_class->put_prev_task(rq, prev);
3113}
3114
3115/*
3116 * Pick up the highest-prio task:
3117 */
3118static inline struct task_struct *
3119pick_next_task(struct rq *rq)
3120{
3121 const struct sched_class *class;
3122 struct task_struct *p;
3123
3124 /*
3125 * Optimization: we know that if all tasks are in
3126 * the fair class we can call that function directly:
3127 */
3128 if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
3129 p = fair_sched_class.pick_next_task(rq);
3130 if (likely(p))
3131 return p;
3132 }
3133
3134 for_each_class(class) {
3135 p = class->pick_next_task(rq);
3136 if (p)
3137 return p;
3138 }
3139
3140 BUG(); /* the idle class will always have a runnable task */
3141}
3142
3143/*
3144 * __schedule() is the main scheduler function.
3145 */
3146static void __sched __schedule(void)
3147{
3148 struct task_struct *prev, *next;
3149 unsigned long *switch_count;
3150 struct rq *rq;
3151 int cpu;
3152
3153need_resched:
3154 preempt_disable();
3155 cpu = smp_processor_id();
3156 rq = cpu_rq(cpu);
3157 rcu_note_context_switch(cpu);
3158 prev = rq->curr;
3159
3160 schedule_debug(prev);
3161
3162 if (sched_feat(HRTICK))
3163 hrtick_clear(rq);
3164
3165 raw_spin_lock_irq(&rq->lock);
3166
3167 switch_count = &prev->nivcsw;
3168 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
3169 if (unlikely(signal_pending_state(prev->state, prev))) {
3170 prev->state = TASK_RUNNING;
3171 } else {
3172 deactivate_task(rq, prev, DEQUEUE_SLEEP);
3173 prev->on_rq = 0;
3174
3175 /*
3176 * If a worker went to sleep, notify and ask workqueue
3177 * whether it wants to wake up a task to maintain
3178 * concurrency.
3179 */
3180 if (prev->flags & PF_WQ_WORKER) {
3181 struct task_struct *to_wakeup;
3182
3183 to_wakeup = wq_worker_sleeping(prev, cpu);
3184 if (to_wakeup)
3185 try_to_wake_up_local(to_wakeup);
3186 }
3187 }
3188 switch_count = &prev->nvcsw;
3189 }
3190
3191 pre_schedule(rq, prev);
3192
3193 if (unlikely(!rq->nr_running))
3194 idle_balance(cpu, rq);
3195
3196 put_prev_task(rq, prev);
3197 next = pick_next_task(rq);
3198 clear_tsk_need_resched(prev);
3199 rq->skip_clock_update = 0;
3200
3201 if (likely(prev != next)) {
3202 rq->nr_switches++;
3203 rq->curr = next;
3204 ++*switch_count;
3205
3206 context_switch(rq, prev, next); /* unlocks the rq */
3207 /*
3208 * The context switch have flipped the stack from under us
3209 * and restored the local variables which were saved when
3210 * this task called schedule() in the past. prev == current
3211 * is still correct, but it can be moved to another cpu/rq.
3212 */
3213 cpu = smp_processor_id();
3214 rq = cpu_rq(cpu);
3215 } else
3216 raw_spin_unlock_irq(&rq->lock);
3217
3218 post_schedule(rq);
3219
3220 preempt_enable_no_resched();
3221 if (need_resched())
3222 goto need_resched;
3223}
3224
3225static inline void sched_submit_work(struct task_struct *tsk)
3226{
3227 if (!tsk->state)
3228 return;
3229 /*
3230 * If we are going to sleep and we have plugged IO queued,
3231 * make sure to submit it to avoid deadlocks.
3232 */
3233 if (blk_needs_flush_plug(tsk))
3234 blk_schedule_flush_plug(tsk);
3235}
3236
3237asmlinkage void __sched schedule(void)
3238{
3239 struct task_struct *tsk = current;
3240
3241 sched_submit_work(tsk);
3242 __schedule();
3243}
3244EXPORT_SYMBOL(schedule);
3245
3246#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3247
3248static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
3249{
3250 if (lock->owner != owner)
3251 return false;
3252
3253 /*
3254 * Ensure we emit the owner->on_cpu, dereference _after_ checking
3255 * lock->owner still matches owner, if that fails, owner might
3256 * point to free()d memory, if it still matches, the rcu_read_lock()
3257 * ensures the memory stays valid.
3258 */
3259 barrier();
3260
3261 return owner->on_cpu;
3262}
3263
3264/*
3265 * Look out! "owner" is an entirely speculative pointer
3266 * access and not reliable.
3267 */
3268int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
3269{
3270 if (!sched_feat(OWNER_SPIN))
3271 return 0;
3272
3273 rcu_read_lock();
3274 while (owner_running(lock, owner)) {
3275 if (need_resched())
3276 break;
3277
3278 arch_mutex_cpu_relax();
3279 }
3280 rcu_read_unlock();
3281
3282 /*
3283 * We break out the loop above on need_resched() and when the
3284 * owner changed, which is a sign for heavy contention. Return
3285 * success only when lock->owner is NULL.
3286 */
3287 return lock->owner == NULL;
3288}
3289#endif
3290
3291#ifdef CONFIG_PREEMPT
3292/*
3293 * this is the entry point to schedule() from in-kernel preemption
3294 * off of preempt_enable. Kernel preemptions off return from interrupt
3295 * occur there and call schedule directly.
3296 */
3297asmlinkage void __sched notrace preempt_schedule(void)
3298{
3299 struct thread_info *ti = current_thread_info();
3300
3301 /*
3302 * If there is a non-zero preempt_count or interrupts are disabled,
3303 * we do not want to preempt the current task. Just return..
3304 */
3305 if (likely(ti->preempt_count || irqs_disabled()))
3306 return;
3307
3308 do {
3309 add_preempt_count_notrace(PREEMPT_ACTIVE);
3310 __schedule();
3311 sub_preempt_count_notrace(PREEMPT_ACTIVE);
3312
3313 /*
3314 * Check again in case we missed a preemption opportunity
3315 * between schedule and now.
3316 */
3317 barrier();
3318 } while (need_resched());
3319}
3320EXPORT_SYMBOL(preempt_schedule);
3321
3322/*
3323 * this is the entry point to schedule() from kernel preemption
3324 * off of irq context.
3325 * Note, that this is called and return with irqs disabled. This will
3326 * protect us against recursive calling from irq.
3327 */
3328asmlinkage void __sched preempt_schedule_irq(void)
3329{
3330 struct thread_info *ti = current_thread_info();
3331
3332 /* Catch callers which need to be fixed */
3333 BUG_ON(ti->preempt_count || !irqs_disabled());
3334
3335 do {
3336 add_preempt_count(PREEMPT_ACTIVE);
3337 local_irq_enable();
3338 __schedule();
3339 local_irq_disable();
3340 sub_preempt_count(PREEMPT_ACTIVE);
3341
3342 /*
3343 * Check again in case we missed a preemption opportunity
3344 * between schedule and now.
3345 */
3346 barrier();
3347 } while (need_resched());
3348}
3349
3350#endif /* CONFIG_PREEMPT */
3351
3352int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
3353 void *key)
3354{
3355 return try_to_wake_up(curr->private, mode, wake_flags);
3356}
3357EXPORT_SYMBOL(default_wake_function);
3358
3359/*
3360 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3361 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3362 * number) then we wake all the non-exclusive tasks and one exclusive task.
3363 *
3364 * There are circumstances in which we can try to wake a task which has already
3365 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3366 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3367 */
3368static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3369 int nr_exclusive, int wake_flags, void *key)
3370{
3371 wait_queue_t *curr, *next;
3372
3373 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
3374 unsigned flags = curr->flags;
3375
3376 if (curr->func(curr, mode, wake_flags, key) &&
3377 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
3378 break;
3379 }
3380}
3381
3382/**
3383 * __wake_up - wake up threads blocked on a waitqueue.
3384 * @q: the waitqueue
3385 * @mode: which threads
3386 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3387 * @key: is directly passed to the wakeup function
3388 *
3389 * It may be assumed that this function implies a write memory barrier before
3390 * changing the task state if and only if any tasks are woken up.
3391 */
3392void __wake_up(wait_queue_head_t *q, unsigned int mode,
3393 int nr_exclusive, void *key)
3394{
3395 unsigned long flags;
3396
3397 spin_lock_irqsave(&q->lock, flags);
3398 __wake_up_common(q, mode, nr_exclusive, 0, key);
3399 spin_unlock_irqrestore(&q->lock, flags);
3400}
3401EXPORT_SYMBOL(__wake_up);
3402
3403/*
3404 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3405 */
3406void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
3407{
3408 __wake_up_common(q, mode, 1, 0, NULL);
3409}
3410EXPORT_SYMBOL_GPL(__wake_up_locked);
3411
3412void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
3413{
3414 __wake_up_common(q, mode, 1, 0, key);
3415}
3416EXPORT_SYMBOL_GPL(__wake_up_locked_key);
3417
3418/**
3419 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3420 * @q: the waitqueue
3421 * @mode: which threads
3422 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3423 * @key: opaque value to be passed to wakeup targets
3424 *
3425 * The sync wakeup differs that the waker knows that it will schedule
3426 * away soon, so while the target thread will be woken up, it will not
3427 * be migrated to another CPU - ie. the two threads are 'synchronized'
3428 * with each other. This can prevent needless bouncing between CPUs.
3429 *
3430 * On UP it can prevent extra preemption.
3431 *
3432 * It may be assumed that this function implies a write memory barrier before
3433 * changing the task state if and only if any tasks are woken up.
3434 */
3435void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
3436 int nr_exclusive, void *key)
3437{
3438 unsigned long flags;
3439 int wake_flags = WF_SYNC;
3440
3441 if (unlikely(!q))
3442 return;
3443
3444 if (unlikely(!nr_exclusive))
3445 wake_flags = 0;
3446
3447 spin_lock_irqsave(&q->lock, flags);
3448 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
3449 spin_unlock_irqrestore(&q->lock, flags);
3450}
3451EXPORT_SYMBOL_GPL(__wake_up_sync_key);
3452
3453/*
3454 * __wake_up_sync - see __wake_up_sync_key()
3455 */
3456void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
3457{
3458 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
3459}
3460EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
3461
3462/**
3463 * complete: - signals a single thread waiting on this completion
3464 * @x: holds the state of this particular completion
3465 *
3466 * This will wake up a single thread waiting on this completion. Threads will be
3467 * awakened in the same order in which they were queued.
3468 *
3469 * See also complete_all(), wait_for_completion() and related routines.
3470 *
3471 * It may be assumed that this function implies a write memory barrier before
3472 * changing the task state if and only if any tasks are woken up.
3473 */
3474void complete(struct completion *x)
3475{
3476 unsigned long flags;
3477
3478 spin_lock_irqsave(&x->wait.lock, flags);
3479 x->done++;
3480 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
3481 spin_unlock_irqrestore(&x->wait.lock, flags);
3482}
3483EXPORT_SYMBOL(complete);
3484
3485/**
3486 * complete_all: - signals all threads waiting on this completion
3487 * @x: holds the state of this particular completion
3488 *
3489 * This will wake up all threads waiting on this particular completion event.
3490 *
3491 * It may be assumed that this function implies a write memory barrier before
3492 * changing the task state if and only if any tasks are woken up.
3493 */
3494void complete_all(struct completion *x)
3495{
3496 unsigned long flags;
3497
3498 spin_lock_irqsave(&x->wait.lock, flags);
3499 x->done += UINT_MAX/2;
3500 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
3501 spin_unlock_irqrestore(&x->wait.lock, flags);
3502}
3503EXPORT_SYMBOL(complete_all);
3504
3505static inline long __sched
3506do_wait_for_common(struct completion *x, long timeout, int state)
3507{
3508 if (!x->done) {
3509 DECLARE_WAITQUEUE(wait, current);
3510
3511 __add_wait_queue_tail_exclusive(&x->wait, &wait);
3512 do {
3513 if (signal_pending_state(state, current)) {
3514 timeout = -ERESTARTSYS;
3515 break;
3516 }
3517 __set_current_state(state);
3518 spin_unlock_irq(&x->wait.lock);
3519 timeout = schedule_timeout(timeout);
3520 spin_lock_irq(&x->wait.lock);
3521 } while (!x->done && timeout);
3522 __remove_wait_queue(&x->wait, &wait);
3523 if (!x->done)
3524 return timeout;
3525 }
3526 x->done--;
3527 return timeout ?: 1;
3528}
3529
3530static long __sched
3531wait_for_common(struct completion *x, long timeout, int state)
3532{
3533 might_sleep();
3534
3535 spin_lock_irq(&x->wait.lock);
3536 timeout = do_wait_for_common(x, timeout, state);
3537 spin_unlock_irq(&x->wait.lock);
3538 return timeout;
3539}
3540
3541/**
3542 * wait_for_completion: - waits for completion of a task
3543 * @x: holds the state of this particular completion
3544 *
3545 * This waits to be signaled for completion of a specific task. It is NOT
3546 * interruptible and there is no timeout.
3547 *
3548 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3549 * and interrupt capability. Also see complete().
3550 */
3551void __sched wait_for_completion(struct completion *x)
3552{
3553 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
3554}
3555EXPORT_SYMBOL(wait_for_completion);
3556
3557/**
3558 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3559 * @x: holds the state of this particular completion
3560 * @timeout: timeout value in jiffies
3561 *
3562 * This waits for either a completion of a specific task to be signaled or for a
3563 * specified timeout to expire. The timeout is in jiffies. It is not
3564 * interruptible.
3565 *
3566 * The return value is 0 if timed out, and positive (at least 1, or number of
3567 * jiffies left till timeout) if completed.
3568 */
3569unsigned long __sched
3570wait_for_completion_timeout(struct completion *x, unsigned long timeout)
3571{
3572 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
3573}
3574EXPORT_SYMBOL(wait_for_completion_timeout);
3575
3576/**
3577 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3578 * @x: holds the state of this particular completion
3579 *
3580 * This waits for completion of a specific task to be signaled. It is
3581 * interruptible.
3582 *
3583 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3584 */
3585int __sched wait_for_completion_interruptible(struct completion *x)
3586{
3587 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
3588 if (t == -ERESTARTSYS)
3589 return t;
3590 return 0;
3591}
3592EXPORT_SYMBOL(wait_for_completion_interruptible);
3593
3594/**
3595 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3596 * @x: holds the state of this particular completion
3597 * @timeout: timeout value in jiffies
3598 *
3599 * This waits for either a completion of a specific task to be signaled or for a
3600 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3601 *
3602 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3603 * positive (at least 1, or number of jiffies left till timeout) if completed.
3604 */
3605long __sched
3606wait_for_completion_interruptible_timeout(struct completion *x,
3607 unsigned long timeout)
3608{
3609 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
3610}
3611EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
3612
3613/**
3614 * wait_for_completion_killable: - waits for completion of a task (killable)
3615 * @x: holds the state of this particular completion
3616 *
3617 * This waits to be signaled for completion of a specific task. It can be
3618 * interrupted by a kill signal.
3619 *
3620 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3621 */
3622int __sched wait_for_completion_killable(struct completion *x)
3623{
3624 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
3625 if (t == -ERESTARTSYS)
3626 return t;
3627 return 0;
3628}
3629EXPORT_SYMBOL(wait_for_completion_killable);
3630
3631/**
3632 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3633 * @x: holds the state of this particular completion
3634 * @timeout: timeout value in jiffies
3635 *
3636 * This waits for either a completion of a specific task to be
3637 * signaled or for a specified timeout to expire. It can be
3638 * interrupted by a kill signal. The timeout is in jiffies.
3639 *
3640 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3641 * positive (at least 1, or number of jiffies left till timeout) if completed.
3642 */
3643long __sched
3644wait_for_completion_killable_timeout(struct completion *x,
3645 unsigned long timeout)
3646{
3647 return wait_for_common(x, timeout, TASK_KILLABLE);
3648}
3649EXPORT_SYMBOL(wait_for_completion_killable_timeout);
3650
3651/**
3652 * try_wait_for_completion - try to decrement a completion without blocking
3653 * @x: completion structure
3654 *
3655 * Returns: 0 if a decrement cannot be done without blocking
3656 * 1 if a decrement succeeded.
3657 *
3658 * If a completion is being used as a counting completion,
3659 * attempt to decrement the counter without blocking. This
3660 * enables us to avoid waiting if the resource the completion
3661 * is protecting is not available.
3662 */
3663bool try_wait_for_completion(struct completion *x)
3664{
3665 unsigned long flags;
3666 int ret = 1;
3667
3668 spin_lock_irqsave(&x->wait.lock, flags);
3669 if (!x->done)
3670 ret = 0;
3671 else
3672 x->done--;
3673 spin_unlock_irqrestore(&x->wait.lock, flags);
3674 return ret;
3675}
3676EXPORT_SYMBOL(try_wait_for_completion);
3677
3678/**
3679 * completion_done - Test to see if a completion has any waiters
3680 * @x: completion structure
3681 *
3682 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3683 * 1 if there are no waiters.
3684 *
3685 */
3686bool completion_done(struct completion *x)
3687{
3688 unsigned long flags;
3689 int ret = 1;
3690
3691 spin_lock_irqsave(&x->wait.lock, flags);
3692 if (!x->done)
3693 ret = 0;
3694 spin_unlock_irqrestore(&x->wait.lock, flags);
3695 return ret;
3696}
3697EXPORT_SYMBOL(completion_done);
3698
3699static long __sched
3700sleep_on_common(wait_queue_head_t *q, int state, long timeout)
3701{
3702 unsigned long flags;
3703 wait_queue_t wait;
3704
3705 init_waitqueue_entry(&wait, current);
3706
3707 __set_current_state(state);
3708
3709 spin_lock_irqsave(&q->lock, flags);
3710 __add_wait_queue(q, &wait);
3711 spin_unlock(&q->lock);
3712 timeout = schedule_timeout(timeout);
3713 spin_lock_irq(&q->lock);
3714 __remove_wait_queue(q, &wait);
3715 spin_unlock_irqrestore(&q->lock, flags);
3716
3717 return timeout;
3718}
3719
3720void __sched interruptible_sleep_on(wait_queue_head_t *q)
3721{
3722 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3723}
3724EXPORT_SYMBOL(interruptible_sleep_on);
3725
3726long __sched
3727interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
3728{
3729 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
3730}
3731EXPORT_SYMBOL(interruptible_sleep_on_timeout);
3732
3733void __sched sleep_on(wait_queue_head_t *q)
3734{
3735 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3736}
3737EXPORT_SYMBOL(sleep_on);
3738
3739long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
3740{
3741 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
3742}
3743EXPORT_SYMBOL(sleep_on_timeout);
3744
3745#ifdef CONFIG_RT_MUTEXES
3746
3747/*
3748 * rt_mutex_setprio - set the current priority of a task
3749 * @p: task
3750 * @prio: prio value (kernel-internal form)
3751 *
3752 * This function changes the 'effective' priority of a task. It does
3753 * not touch ->normal_prio like __setscheduler().
3754 *
3755 * Used by the rt_mutex code to implement priority inheritance logic.
3756 */
3757void rt_mutex_setprio(struct task_struct *p, int prio)
3758{
3759 int oldprio, on_rq, running;
3760 struct rq *rq;
3761 const struct sched_class *prev_class;
3762
3763 BUG_ON(prio < 0 || prio > MAX_PRIO);
3764
3765 rq = __task_rq_lock(p);
3766
3767 trace_sched_pi_setprio(p, prio);
3768 oldprio = p->prio;
3769 prev_class = p->sched_class;
3770 on_rq = p->on_rq;
3771 running = task_current(rq, p);
3772 if (on_rq)
3773 dequeue_task(rq, p, 0);
3774 if (running)
3775 p->sched_class->put_prev_task(rq, p);
3776
3777 if (rt_prio(prio))
3778 p->sched_class = &rt_sched_class;
3779 else
3780 p->sched_class = &fair_sched_class;
3781
3782 p->prio = prio;
3783
3784 if (running)
3785 p->sched_class->set_curr_task(rq);
3786 if (on_rq)
3787 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
3788
3789 check_class_changed(rq, p, prev_class, oldprio);
3790 __task_rq_unlock(rq);
3791}
3792
3793#endif
3794
3795void set_user_nice(struct task_struct *p, long nice)
3796{
3797 int old_prio, delta, on_rq;
3798 unsigned long flags;
3799 struct rq *rq;
3800
3801 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
3802 return;
3803 /*
3804 * We have to be careful, if called from sys_setpriority(),
3805 * the task might be in the middle of scheduling on another CPU.
3806 */
3807 rq = task_rq_lock(p, &flags);
3808 /*
3809 * The RT priorities are set via sched_setscheduler(), but we still
3810 * allow the 'normal' nice value to be set - but as expected
3811 * it wont have any effect on scheduling until the task is
3812 * SCHED_FIFO/SCHED_RR:
3813 */
3814 if (task_has_rt_policy(p)) {
3815 p->static_prio = NICE_TO_PRIO(nice);
3816 goto out_unlock;
3817 }
3818 on_rq = p->on_rq;
3819 if (on_rq)
3820 dequeue_task(rq, p, 0);
3821
3822 p->static_prio = NICE_TO_PRIO(nice);
3823 set_load_weight(p);
3824 old_prio = p->prio;
3825 p->prio = effective_prio(p);
3826 delta = p->prio - old_prio;
3827
3828 if (on_rq) {
3829 enqueue_task(rq, p, 0);
3830 /*
3831 * If the task increased its priority or is running and
3832 * lowered its priority, then reschedule its CPU:
3833 */
3834 if (delta < 0 || (delta > 0 && task_running(rq, p)))
3835 resched_task(rq->curr);
3836 }
3837out_unlock:
3838 task_rq_unlock(rq, p, &flags);
3839}
3840EXPORT_SYMBOL(set_user_nice);
3841
3842/*
3843 * can_nice - check if a task can reduce its nice value
3844 * @p: task
3845 * @nice: nice value
3846 */
3847int can_nice(const struct task_struct *p, const int nice)
3848{
3849 /* convert nice value [19,-20] to rlimit style value [1,40] */
3850 int nice_rlim = 20 - nice;
3851
3852 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
3853 capable(CAP_SYS_NICE));
3854}
3855
3856#ifdef __ARCH_WANT_SYS_NICE
3857
3858/*
3859 * sys_nice - change the priority of the current process.
3860 * @increment: priority increment
3861 *
3862 * sys_setpriority is a more generic, but much slower function that
3863 * does similar things.
3864 */
3865SYSCALL_DEFINE1(nice, int, increment)
3866{
3867 long nice, retval;
3868
3869 /*
3870 * Setpriority might change our priority at the same moment.
3871 * We don't have to worry. Conceptually one call occurs first
3872 * and we have a single winner.
3873 */
3874 if (increment < -40)
3875 increment = -40;
3876 if (increment > 40)
3877 increment = 40;
3878
3879 nice = TASK_NICE(current) + increment;
3880 if (nice < -20)
3881 nice = -20;
3882 if (nice > 19)
3883 nice = 19;
3884
3885 if (increment < 0 && !can_nice(current, nice))
3886 return -EPERM;
3887
3888 retval = security_task_setnice(current, nice);
3889 if (retval)
3890 return retval;
3891
3892 set_user_nice(current, nice);
3893 return 0;
3894}
3895
3896#endif
3897
3898/**
3899 * task_prio - return the priority value of a given task.
3900 * @p: the task in question.
3901 *
3902 * This is the priority value as seen by users in /proc.
3903 * RT tasks are offset by -200. Normal tasks are centered
3904 * around 0, value goes from -16 to +15.
3905 */
3906int task_prio(const struct task_struct *p)
3907{
3908 return p->prio - MAX_RT_PRIO;
3909}
3910
3911/**
3912 * task_nice - return the nice value of a given task.
3913 * @p: the task in question.
3914 */
3915int task_nice(const struct task_struct *p)
3916{
3917 return TASK_NICE(p);
3918}
3919EXPORT_SYMBOL(task_nice);
3920
3921/**
3922 * idle_cpu - is a given cpu idle currently?
3923 * @cpu: the processor in question.
3924 */
3925int idle_cpu(int cpu)
3926{
3927 struct rq *rq = cpu_rq(cpu);
3928
3929 if (rq->curr != rq->idle)
3930 return 0;
3931
3932 if (rq->nr_running)
3933 return 0;
3934
3935#ifdef CONFIG_SMP
3936 if (!llist_empty(&rq->wake_list))
3937 return 0;
3938#endif
3939
3940 return 1;
3941}
3942
3943/**
3944 * idle_task - return the idle task for a given cpu.
3945 * @cpu: the processor in question.
3946 */
3947struct task_struct *idle_task(int cpu)
3948{
3949 return cpu_rq(cpu)->idle;
3950}
3951
3952/**
3953 * find_process_by_pid - find a process with a matching PID value.
3954 * @pid: the pid in question.
3955 */
3956static struct task_struct *find_process_by_pid(pid_t pid)
3957{
3958 return pid ? find_task_by_vpid(pid) : current;
3959}
3960
3961/* Actually do priority change: must hold rq lock. */
3962static void
3963__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
3964{
3965 p->policy = policy;
3966 p->rt_priority = prio;
3967 p->normal_prio = normal_prio(p);
3968 /* we are holding p->pi_lock already */
3969 p->prio = rt_mutex_getprio(p);
3970 if (rt_prio(p->prio))
3971 p->sched_class = &rt_sched_class;
3972 else
3973 p->sched_class = &fair_sched_class;
3974 set_load_weight(p);
3975}
3976
3977/*
3978 * check the target process has a UID that matches the current process's
3979 */
3980static bool check_same_owner(struct task_struct *p)
3981{
3982 const struct cred *cred = current_cred(), *pcred;
3983 bool match;
3984
3985 rcu_read_lock();
3986 pcred = __task_cred(p);
3987 if (cred->user->user_ns == pcred->user->user_ns)
3988 match = (cred->euid == pcred->euid ||
3989 cred->euid == pcred->uid);
3990 else
3991 match = false;
3992 rcu_read_unlock();
3993 return match;
3994}
3995
3996static int __sched_setscheduler(struct task_struct *p, int policy,
3997 const struct sched_param *param, bool user)
3998{
3999 int retval, oldprio, oldpolicy = -1, on_rq, running;
4000 unsigned long flags;
4001 const struct sched_class *prev_class;
4002 struct rq *rq;
4003 int reset_on_fork;
4004
4005 /* may grab non-irq protected spin_locks */
4006 BUG_ON(in_interrupt());
4007recheck:
4008 /* double check policy once rq lock held */
4009 if (policy < 0) {
4010 reset_on_fork = p->sched_reset_on_fork;
4011 policy = oldpolicy = p->policy;
4012 } else {
4013 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
4014 policy &= ~SCHED_RESET_ON_FORK;
4015
4016 if (policy != SCHED_FIFO && policy != SCHED_RR &&
4017 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4018 policy != SCHED_IDLE)
4019 return -EINVAL;
4020 }
4021
4022 /*
4023 * Valid priorities for SCHED_FIFO and SCHED_RR are
4024 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4025 * SCHED_BATCH and SCHED_IDLE is 0.
4026 */
4027 if (param->sched_priority < 0 ||
4028 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4029 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4030 return -EINVAL;
4031 if (rt_policy(policy) != (param->sched_priority != 0))
4032 return -EINVAL;
4033
4034 /*
4035 * Allow unprivileged RT tasks to decrease priority:
4036 */
4037 if (user && !capable(CAP_SYS_NICE)) {
4038 if (rt_policy(policy)) {
4039 unsigned long rlim_rtprio =
4040 task_rlimit(p, RLIMIT_RTPRIO);
4041
4042 /* can't set/change the rt policy */
4043 if (policy != p->policy && !rlim_rtprio)
4044 return -EPERM;
4045
4046 /* can't increase priority */
4047 if (param->sched_priority > p->rt_priority &&
4048 param->sched_priority > rlim_rtprio)
4049 return -EPERM;
4050 }
4051
4052 /*
4053 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4054 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4055 */
4056 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
4057 if (!can_nice(p, TASK_NICE(p)))
4058 return -EPERM;
4059 }
4060
4061 /* can't change other user's priorities */
4062 if (!check_same_owner(p))
4063 return -EPERM;
4064
4065 /* Normal users shall not reset the sched_reset_on_fork flag */
4066 if (p->sched_reset_on_fork && !reset_on_fork)
4067 return -EPERM;
4068 }
4069
4070 if (user) {
4071 retval = security_task_setscheduler(p);
4072 if (retval)
4073 return retval;
4074 }
4075
4076 /*
4077 * make sure no PI-waiters arrive (or leave) while we are
4078 * changing the priority of the task:
4079 *
4080 * To be able to change p->policy safely, the appropriate
4081 * runqueue lock must be held.
4082 */
4083 rq = task_rq_lock(p, &flags);
4084
4085 /*
4086 * Changing the policy of the stop threads its a very bad idea
4087 */
4088 if (p == rq->stop) {
4089 task_rq_unlock(rq, p, &flags);
4090 return -EINVAL;
4091 }
4092
4093 /*
4094 * If not changing anything there's no need to proceed further:
4095 */
4096 if (unlikely(policy == p->policy && (!rt_policy(policy) ||
4097 param->sched_priority == p->rt_priority))) {
4098
4099 __task_rq_unlock(rq);
4100 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4101 return 0;
4102 }
4103
4104#ifdef CONFIG_RT_GROUP_SCHED
4105 if (user) {
4106 /*
4107 * Do not allow realtime tasks into groups that have no runtime
4108 * assigned.
4109 */
4110 if (rt_bandwidth_enabled() && rt_policy(policy) &&
4111 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
4112 !task_group_is_autogroup(task_group(p))) {
4113 task_rq_unlock(rq, p, &flags);
4114 return -EPERM;
4115 }
4116 }
4117#endif
4118
4119 /* recheck policy now with rq lock held */
4120 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4121 policy = oldpolicy = -1;
4122 task_rq_unlock(rq, p, &flags);
4123 goto recheck;
4124 }
4125 on_rq = p->on_rq;
4126 running = task_current(rq, p);
4127 if (on_rq)
4128 deactivate_task(rq, p, 0);
4129 if (running)
4130 p->sched_class->put_prev_task(rq, p);
4131
4132 p->sched_reset_on_fork = reset_on_fork;
4133
4134 oldprio = p->prio;
4135 prev_class = p->sched_class;
4136 __setscheduler(rq, p, policy, param->sched_priority);
4137
4138 if (running)
4139 p->sched_class->set_curr_task(rq);
4140 if (on_rq)
4141 activate_task(rq, p, 0);
4142
4143 check_class_changed(rq, p, prev_class, oldprio);
4144 task_rq_unlock(rq, p, &flags);
4145
4146 rt_mutex_adjust_pi(p);
4147
4148 return 0;
4149}
4150
4151/**
4152 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4153 * @p: the task in question.
4154 * @policy: new policy.
4155 * @param: structure containing the new RT priority.
4156 *
4157 * NOTE that the task may be already dead.
4158 */
4159int sched_setscheduler(struct task_struct *p, int policy,
4160 const struct sched_param *param)
4161{
4162 return __sched_setscheduler(p, policy, param, true);
4163}
4164EXPORT_SYMBOL_GPL(sched_setscheduler);
4165
4166/**
4167 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4168 * @p: the task in question.
4169 * @policy: new policy.
4170 * @param: structure containing the new RT priority.
4171 *
4172 * Just like sched_setscheduler, only don't bother checking if the
4173 * current context has permission. For example, this is needed in
4174 * stop_machine(): we create temporary high priority worker threads,
4175 * but our caller might not have that capability.
4176 */
4177int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4178 const struct sched_param *param)
4179{
4180 return __sched_setscheduler(p, policy, param, false);
4181}
4182
4183static int
4184do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4185{
4186 struct sched_param lparam;
4187 struct task_struct *p;
4188 int retval;
4189
4190 if (!param || pid < 0)
4191 return -EINVAL;
4192 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4193 return -EFAULT;
4194
4195 rcu_read_lock();
4196 retval = -ESRCH;
4197 p = find_process_by_pid(pid);
4198 if (p != NULL)
4199 retval = sched_setscheduler(p, policy, &lparam);
4200 rcu_read_unlock();
4201
4202 return retval;
4203}
4204
4205/**
4206 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4207 * @pid: the pid in question.
4208 * @policy: new policy.
4209 * @param: structure containing the new RT priority.
4210 */
4211SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
4212 struct sched_param __user *, param)
4213{
4214 /* negative values for policy are not valid */
4215 if (policy < 0)
4216 return -EINVAL;
4217
4218 return do_sched_setscheduler(pid, policy, param);
4219}
4220
4221/**
4222 * sys_sched_setparam - set/change the RT priority of a thread
4223 * @pid: the pid in question.
4224 * @param: structure containing the new RT priority.
4225 */
4226SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
4227{
4228 return do_sched_setscheduler(pid, -1, param);
4229}
4230
4231/**
4232 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4233 * @pid: the pid in question.
4234 */
4235SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
4236{
4237 struct task_struct *p;
4238 int retval;
4239
4240 if (pid < 0)
4241 return -EINVAL;
4242
4243 retval = -ESRCH;
4244 rcu_read_lock();
4245 p = find_process_by_pid(pid);
4246 if (p) {
4247 retval = security_task_getscheduler(p);
4248 if (!retval)
4249 retval = p->policy
4250 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
4251 }
4252 rcu_read_unlock();
4253 return retval;
4254}
4255
4256/**
4257 * sys_sched_getparam - get the RT priority of a thread
4258 * @pid: the pid in question.
4259 * @param: structure containing the RT priority.
4260 */
4261SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
4262{
4263 struct sched_param lp;
4264 struct task_struct *p;
4265 int retval;
4266
4267 if (!param || pid < 0)
4268 return -EINVAL;
4269
4270 rcu_read_lock();
4271 p = find_process_by_pid(pid);
4272 retval = -ESRCH;
4273 if (!p)
4274 goto out_unlock;
4275
4276 retval = security_task_getscheduler(p);
4277 if (retval)
4278 goto out_unlock;
4279
4280 lp.sched_priority = p->rt_priority;
4281 rcu_read_unlock();
4282
4283 /*
4284 * This one might sleep, we cannot do it with a spinlock held ...
4285 */
4286 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4287
4288 return retval;
4289
4290out_unlock:
4291 rcu_read_unlock();
4292 return retval;
4293}
4294
4295long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4296{
4297 cpumask_var_t cpus_allowed, new_mask;
4298 struct task_struct *p;
4299 int retval;
4300
4301 get_online_cpus();
4302 rcu_read_lock();
4303
4304 p = find_process_by_pid(pid);
4305 if (!p) {
4306 rcu_read_unlock();
4307 put_online_cpus();
4308 return -ESRCH;
4309 }
4310
4311 /* Prevent p going away */
4312 get_task_struct(p);
4313 rcu_read_unlock();
4314
4315 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4316 retval = -ENOMEM;
4317 goto out_put_task;
4318 }
4319 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4320 retval = -ENOMEM;
4321 goto out_free_cpus_allowed;
4322 }
4323 retval = -EPERM;
4324 if (!check_same_owner(p) && !task_ns_capable(p, CAP_SYS_NICE))
4325 goto out_unlock;
4326
4327 retval = security_task_setscheduler(p);
4328 if (retval)
4329 goto out_unlock;
4330
4331 cpuset_cpus_allowed(p, cpus_allowed);
4332 cpumask_and(new_mask, in_mask, cpus_allowed);
4333again:
4334 retval = set_cpus_allowed_ptr(p, new_mask);
4335
4336 if (!retval) {
4337 cpuset_cpus_allowed(p, cpus_allowed);
4338 if (!cpumask_subset(new_mask, cpus_allowed)) {
4339 /*
4340 * We must have raced with a concurrent cpuset
4341 * update. Just reset the cpus_allowed to the
4342 * cpuset's cpus_allowed
4343 */
4344 cpumask_copy(new_mask, cpus_allowed);
4345 goto again;
4346 }
4347 }
4348out_unlock:
4349 free_cpumask_var(new_mask);
4350out_free_cpus_allowed:
4351 free_cpumask_var(cpus_allowed);
4352out_put_task:
4353 put_task_struct(p);
4354 put_online_cpus();
4355 return retval;
4356}
4357
4358static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4359 struct cpumask *new_mask)
4360{
4361 if (len < cpumask_size())
4362 cpumask_clear(new_mask);
4363 else if (len > cpumask_size())
4364 len = cpumask_size();
4365
4366 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4367}
4368
4369/**
4370 * sys_sched_setaffinity - set the cpu affinity of a process
4371 * @pid: pid of the process
4372 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4373 * @user_mask_ptr: user-space pointer to the new cpu mask
4374 */
4375SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4376 unsigned long __user *, user_mask_ptr)
4377{
4378 cpumask_var_t new_mask;
4379 int retval;
4380
4381 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4382 return -ENOMEM;
4383
4384 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4385 if (retval == 0)
4386 retval = sched_setaffinity(pid, new_mask);
4387 free_cpumask_var(new_mask);
4388 return retval;
4389}
4390
4391long sched_getaffinity(pid_t pid, struct cpumask *mask)
4392{
4393 struct task_struct *p;
4394 unsigned long flags;
4395 int retval;
4396
4397 get_online_cpus();
4398 rcu_read_lock();
4399
4400 retval = -ESRCH;
4401 p = find_process_by_pid(pid);
4402 if (!p)
4403 goto out_unlock;
4404
4405 retval = security_task_getscheduler(p);
4406 if (retval)
4407 goto out_unlock;
4408
4409 raw_spin_lock_irqsave(&p->pi_lock, flags);
4410 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
4411 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4412
4413out_unlock:
4414 rcu_read_unlock();
4415 put_online_cpus();
4416
4417 return retval;
4418}
4419
4420/**
4421 * sys_sched_getaffinity - get the cpu affinity of a process
4422 * @pid: pid of the process
4423 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4424 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4425 */
4426SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4427 unsigned long __user *, user_mask_ptr)
4428{
4429 int ret;
4430 cpumask_var_t mask;
4431
4432 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4433 return -EINVAL;
4434 if (len & (sizeof(unsigned long)-1))
4435 return -EINVAL;
4436
4437 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4438 return -ENOMEM;
4439
4440 ret = sched_getaffinity(pid, mask);
4441 if (ret == 0) {
4442 size_t retlen = min_t(size_t, len, cpumask_size());
4443
4444 if (copy_to_user(user_mask_ptr, mask, retlen))
4445 ret = -EFAULT;
4446 else
4447 ret = retlen;
4448 }
4449 free_cpumask_var(mask);
4450
4451 return ret;
4452}
4453
4454/**
4455 * sys_sched_yield - yield the current processor to other threads.
4456 *
4457 * This function yields the current CPU to other tasks. If there are no
4458 * other threads running on this CPU then this function will return.
4459 */
4460SYSCALL_DEFINE0(sched_yield)
4461{
4462 struct rq *rq = this_rq_lock();
4463
4464 schedstat_inc(rq, yld_count);
4465 current->sched_class->yield_task(rq);
4466
4467 /*
4468 * Since we are going to call schedule() anyway, there's
4469 * no need to preempt or enable interrupts:
4470 */
4471 __release(rq->lock);
4472 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4473 do_raw_spin_unlock(&rq->lock);
4474 preempt_enable_no_resched();
4475
4476 schedule();
4477
4478 return 0;
4479}
4480
4481static inline int should_resched(void)
4482{
4483 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
4484}
4485
4486static void __cond_resched(void)
4487{
4488 add_preempt_count(PREEMPT_ACTIVE);
4489 __schedule();
4490 sub_preempt_count(PREEMPT_ACTIVE);
4491}
4492
4493int __sched _cond_resched(void)
4494{
4495 if (should_resched()) {
4496 __cond_resched();
4497 return 1;
4498 }
4499 return 0;
4500}
4501EXPORT_SYMBOL(_cond_resched);
4502
4503/*
4504 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4505 * call schedule, and on return reacquire the lock.
4506 *
4507 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4508 * operations here to prevent schedule() from being called twice (once via
4509 * spin_unlock(), once by hand).
4510 */
4511int __cond_resched_lock(spinlock_t *lock)
4512{
4513 int resched = should_resched();
4514 int ret = 0;
4515
4516 lockdep_assert_held(lock);
4517
4518 if (spin_needbreak(lock) || resched) {
4519 spin_unlock(lock);
4520 if (resched)
4521 __cond_resched();
4522 else
4523 cpu_relax();
4524 ret = 1;
4525 spin_lock(lock);
4526 }
4527 return ret;
4528}
4529EXPORT_SYMBOL(__cond_resched_lock);
4530
4531int __sched __cond_resched_softirq(void)
4532{
4533 BUG_ON(!in_softirq());
4534
4535 if (should_resched()) {
4536 local_bh_enable();
4537 __cond_resched();
4538 local_bh_disable();
4539 return 1;
4540 }
4541 return 0;
4542}
4543EXPORT_SYMBOL(__cond_resched_softirq);
4544
4545/**
4546 * yield - yield the current processor to other threads.
4547 *
4548 * This is a shortcut for kernel-space yielding - it marks the
4549 * thread runnable and calls sys_sched_yield().
4550 */
4551void __sched yield(void)
4552{
4553 set_current_state(TASK_RUNNING);
4554 sys_sched_yield();
4555}
4556EXPORT_SYMBOL(yield);
4557
4558/**
4559 * yield_to - yield the current processor to another thread in
4560 * your thread group, or accelerate that thread toward the
4561 * processor it's on.
4562 * @p: target task
4563 * @preempt: whether task preemption is allowed or not
4564 *
4565 * It's the caller's job to ensure that the target task struct
4566 * can't go away on us before we can do any checks.
4567 *
4568 * Returns true if we indeed boosted the target task.
4569 */
4570bool __sched yield_to(struct task_struct *p, bool preempt)
4571{
4572 struct task_struct *curr = current;
4573 struct rq *rq, *p_rq;
4574 unsigned long flags;
4575 bool yielded = 0;
4576
4577 local_irq_save(flags);
4578 rq = this_rq();
4579
4580again:
4581 p_rq = task_rq(p);
4582 double_rq_lock(rq, p_rq);
4583 while (task_rq(p) != p_rq) {
4584 double_rq_unlock(rq, p_rq);
4585 goto again;
4586 }
4587
4588 if (!curr->sched_class->yield_to_task)
4589 goto out;
4590
4591 if (curr->sched_class != p->sched_class)
4592 goto out;
4593
4594 if (task_running(p_rq, p) || p->state)
4595 goto out;
4596
4597 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4598 if (yielded) {
4599 schedstat_inc(rq, yld_count);
4600 /*
4601 * Make p's CPU reschedule; pick_next_entity takes care of
4602 * fairness.
4603 */
4604 if (preempt && rq != p_rq)
4605 resched_task(p_rq->curr);
4606 } else {
4607 /*
4608 * We might have set it in task_yield_fair(), but are
4609 * not going to schedule(), so don't want to skip
4610 * the next update.
4611 */
4612 rq->skip_clock_update = 0;
4613 }
4614
4615out:
4616 double_rq_unlock(rq, p_rq);
4617 local_irq_restore(flags);
4618
4619 if (yielded)
4620 schedule();
4621
4622 return yielded;
4623}
4624EXPORT_SYMBOL_GPL(yield_to);
4625
4626/*
4627 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4628 * that process accounting knows that this is a task in IO wait state.
4629 */
4630void __sched io_schedule(void)
4631{
4632 struct rq *rq = raw_rq();
4633
4634 delayacct_blkio_start();
4635 atomic_inc(&rq->nr_iowait);
4636 blk_flush_plug(current);
4637 current->in_iowait = 1;
4638 schedule();
4639 current->in_iowait = 0;
4640 atomic_dec(&rq->nr_iowait);
4641 delayacct_blkio_end();
4642}
4643EXPORT_SYMBOL(io_schedule);
4644
4645long __sched io_schedule_timeout(long timeout)
4646{
4647 struct rq *rq = raw_rq();
4648 long ret;
4649
4650 delayacct_blkio_start();
4651 atomic_inc(&rq->nr_iowait);
4652 blk_flush_plug(current);
4653 current->in_iowait = 1;
4654 ret = schedule_timeout(timeout);
4655 current->in_iowait = 0;
4656 atomic_dec(&rq->nr_iowait);
4657 delayacct_blkio_end();
4658 return ret;
4659}
4660
4661/**
4662 * sys_sched_get_priority_max - return maximum RT priority.
4663 * @policy: scheduling class.
4664 *
4665 * this syscall returns the maximum rt_priority that can be used
4666 * by a given scheduling class.
4667 */
4668SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
4669{
4670 int ret = -EINVAL;
4671
4672 switch (policy) {
4673 case SCHED_FIFO:
4674 case SCHED_RR:
4675 ret = MAX_USER_RT_PRIO-1;
4676 break;
4677 case SCHED_NORMAL:
4678 case SCHED_BATCH:
4679 case SCHED_IDLE:
4680 ret = 0;
4681 break;
4682 }
4683 return ret;
4684}
4685
4686/**
4687 * sys_sched_get_priority_min - return minimum RT priority.
4688 * @policy: scheduling class.
4689 *
4690 * this syscall returns the minimum rt_priority that can be used
4691 * by a given scheduling class.
4692 */
4693SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
4694{
4695 int ret = -EINVAL;
4696
4697 switch (policy) {
4698 case SCHED_FIFO:
4699 case SCHED_RR:
4700 ret = 1;
4701 break;
4702 case SCHED_NORMAL:
4703 case SCHED_BATCH:
4704 case SCHED_IDLE:
4705 ret = 0;
4706 }
4707 return ret;
4708}
4709
4710/**
4711 * sys_sched_rr_get_interval - return the default timeslice of a process.
4712 * @pid: pid of the process.
4713 * @interval: userspace pointer to the timeslice value.
4714 *
4715 * this syscall writes the default timeslice value of a given process
4716 * into the user-space timespec buffer. A value of '0' means infinity.
4717 */
4718SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4719 struct timespec __user *, interval)
4720{
4721 struct task_struct *p;
4722 unsigned int time_slice;
4723 unsigned long flags;
4724 struct rq *rq;
4725 int retval;
4726 struct timespec t;
4727
4728 if (pid < 0)
4729 return -EINVAL;
4730
4731 retval = -ESRCH;
4732 rcu_read_lock();
4733 p = find_process_by_pid(pid);
4734 if (!p)
4735 goto out_unlock;
4736
4737 retval = security_task_getscheduler(p);
4738 if (retval)
4739 goto out_unlock;
4740
4741 rq = task_rq_lock(p, &flags);
4742 time_slice = p->sched_class->get_rr_interval(rq, p);
4743 task_rq_unlock(rq, p, &flags);
4744
4745 rcu_read_unlock();
4746 jiffies_to_timespec(time_slice, &t);
4747 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
4748 return retval;
4749
4750out_unlock:
4751 rcu_read_unlock();
4752 return retval;
4753}
4754
4755static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
4756
4757void sched_show_task(struct task_struct *p)
4758{
4759 unsigned long free = 0;
4760 unsigned state;
4761
4762 state = p->state ? __ffs(p->state) + 1 : 0;
4763 printk(KERN_INFO "%-15.15s %c", p->comm,
4764 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4765#if BITS_PER_LONG == 32
4766 if (state == TASK_RUNNING)
4767 printk(KERN_CONT " running ");
4768 else
4769 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
4770#else
4771 if (state == TASK_RUNNING)
4772 printk(KERN_CONT " running task ");
4773 else
4774 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
4775#endif
4776#ifdef CONFIG_DEBUG_STACK_USAGE
4777 free = stack_not_used(p);
4778#endif
4779 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4780 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
4781 (unsigned long)task_thread_info(p)->flags);
4782
4783 show_stack(p, NULL);
4784}
4785
4786void show_state_filter(unsigned long state_filter)
4787{
4788 struct task_struct *g, *p;
4789
4790#if BITS_PER_LONG == 32
4791 printk(KERN_INFO
4792 " task PC stack pid father\n");
4793#else
4794 printk(KERN_INFO
4795 " task PC stack pid father\n");
4796#endif
4797 rcu_read_lock();
4798 do_each_thread(g, p) {
4799 /*
4800 * reset the NMI-timeout, listing all files on a slow
4801 * console might take a lot of time:
4802 */
4803 touch_nmi_watchdog();
4804 if (!state_filter || (p->state & state_filter))
4805 sched_show_task(p);
4806 } while_each_thread(g, p);
4807
4808 touch_all_softlockup_watchdogs();
4809
4810#ifdef CONFIG_SCHED_DEBUG
4811 sysrq_sched_debug_show();
4812#endif
4813 rcu_read_unlock();
4814 /*
4815 * Only show locks if all tasks are dumped:
4816 */
4817 if (!state_filter)
4818 debug_show_all_locks();
4819}
4820
4821void __cpuinit init_idle_bootup_task(struct task_struct *idle)
4822{
4823 idle->sched_class = &idle_sched_class;
4824}
4825
4826/**
4827 * init_idle - set up an idle thread for a given CPU
4828 * @idle: task in question
4829 * @cpu: cpu the idle task belongs to
4830 *
4831 * NOTE: this function does not set the idle thread's NEED_RESCHED
4832 * flag, to make booting more robust.
4833 */
4834void __cpuinit init_idle(struct task_struct *idle, int cpu)
4835{
4836 struct rq *rq = cpu_rq(cpu);
4837 unsigned long flags;
4838
4839 raw_spin_lock_irqsave(&rq->lock, flags);
4840
4841 __sched_fork(idle);
4842 idle->state = TASK_RUNNING;
4843 idle->se.exec_start = sched_clock();
4844
4845 do_set_cpus_allowed(idle, cpumask_of(cpu));
4846 /*
4847 * We're having a chicken and egg problem, even though we are
4848 * holding rq->lock, the cpu isn't yet set to this cpu so the
4849 * lockdep check in task_group() will fail.
4850 *
4851 * Similar case to sched_fork(). / Alternatively we could
4852 * use task_rq_lock() here and obtain the other rq->lock.
4853 *
4854 * Silence PROVE_RCU
4855 */
4856 rcu_read_lock();
4857 __set_task_cpu(idle, cpu);
4858 rcu_read_unlock();
4859
4860 rq->curr = rq->idle = idle;
4861#if defined(CONFIG_SMP)
4862 idle->on_cpu = 1;
4863#endif
4864 raw_spin_unlock_irqrestore(&rq->lock, flags);
4865
4866 /* Set the preempt count _outside_ the spinlocks! */
4867 task_thread_info(idle)->preempt_count = 0;
4868
4869 /*
4870 * The idle tasks have their own, simple scheduling class:
4871 */
4872 idle->sched_class = &idle_sched_class;
4873 ftrace_graph_init_idle_task(idle, cpu);
4874#if defined(CONFIG_SMP)
4875 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
4876#endif
4877}
4878
4879#ifdef CONFIG_SMP
4880void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
4881{
4882 if (p->sched_class && p->sched_class->set_cpus_allowed)
4883 p->sched_class->set_cpus_allowed(p, new_mask);
4884
4885 cpumask_copy(&p->cpus_allowed, new_mask);
4886 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
4887}
4888
4889/*
4890 * This is how migration works:
4891 *
4892 * 1) we invoke migration_cpu_stop() on the target CPU using
4893 * stop_one_cpu().
4894 * 2) stopper starts to run (implicitly forcing the migrated thread
4895 * off the CPU)
4896 * 3) it checks whether the migrated task is still in the wrong runqueue.
4897 * 4) if it's in the wrong runqueue then the migration thread removes
4898 * it and puts it into the right queue.
4899 * 5) stopper completes and stop_one_cpu() returns and the migration
4900 * is done.
4901 */
4902
4903/*
4904 * Change a given task's CPU affinity. Migrate the thread to a
4905 * proper CPU and schedule it away if the CPU it's executing on
4906 * is removed from the allowed bitmask.
4907 *
4908 * NOTE: the caller must have a valid reference to the task, the
4909 * task must not exit() & deallocate itself prematurely. The
4910 * call is not atomic; no spinlocks may be held.
4911 */
4912int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
4913{
4914 unsigned long flags;
4915 struct rq *rq;
4916 unsigned int dest_cpu;
4917 int ret = 0;
4918
4919 rq = task_rq_lock(p, &flags);
4920
4921 if (cpumask_equal(&p->cpus_allowed, new_mask))
4922 goto out;
4923
4924 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
4925 ret = -EINVAL;
4926 goto out;
4927 }
4928
4929 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
4930 ret = -EINVAL;
4931 goto out;
4932 }
4933
4934 do_set_cpus_allowed(p, new_mask);
4935
4936 /* Can the task run on the task's current CPU? If so, we're done */
4937 if (cpumask_test_cpu(task_cpu(p), new_mask))
4938 goto out;
4939
4940 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
4941 if (p->on_rq) {
4942 struct migration_arg arg = { p, dest_cpu };
4943 /* Need help from migration thread: drop lock and wait. */
4944 task_rq_unlock(rq, p, &flags);
4945 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
4946 tlb_migrate_finish(p->mm);
4947 return 0;
4948 }
4949out:
4950 task_rq_unlock(rq, p, &flags);
4951
4952 return ret;
4953}
4954EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
4955
4956/*
4957 * Move (not current) task off this cpu, onto dest cpu. We're doing
4958 * this because either it can't run here any more (set_cpus_allowed()
4959 * away from this CPU, or CPU going down), or because we're
4960 * attempting to rebalance this task on exec (sched_exec).
4961 *
4962 * So we race with normal scheduler movements, but that's OK, as long
4963 * as the task is no longer on this CPU.
4964 *
4965 * Returns non-zero if task was successfully migrated.
4966 */
4967static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
4968{
4969 struct rq *rq_dest, *rq_src;
4970 int ret = 0;
4971
4972 if (unlikely(!cpu_active(dest_cpu)))
4973 return ret;
4974
4975 rq_src = cpu_rq(src_cpu);
4976 rq_dest = cpu_rq(dest_cpu);
4977
4978 raw_spin_lock(&p->pi_lock);
4979 double_rq_lock(rq_src, rq_dest);
4980 /* Already moved. */
4981 if (task_cpu(p) != src_cpu)
4982 goto done;
4983 /* Affinity changed (again). */
4984 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
4985 goto fail;
4986
4987 /*
4988 * If we're not on a rq, the next wake-up will ensure we're
4989 * placed properly.
4990 */
4991 if (p->on_rq) {
4992 deactivate_task(rq_src, p, 0);
4993 set_task_cpu(p, dest_cpu);
4994 activate_task(rq_dest, p, 0);
4995 check_preempt_curr(rq_dest, p, 0);
4996 }
4997done:
4998 ret = 1;
4999fail:
5000 double_rq_unlock(rq_src, rq_dest);
5001 raw_spin_unlock(&p->pi_lock);
5002 return ret;
5003}
5004
5005/*
5006 * migration_cpu_stop - this will be executed by a highprio stopper thread
5007 * and performs thread migration by bumping thread off CPU then
5008 * 'pushing' onto another runqueue.
5009 */
5010static int migration_cpu_stop(void *data)
5011{
5012 struct migration_arg *arg = data;
5013
5014 /*
5015 * The original target cpu might have gone down and we might
5016 * be on another cpu but it doesn't matter.
5017 */
5018 local_irq_disable();
5019 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
5020 local_irq_enable();
5021 return 0;
5022}
5023
5024#ifdef CONFIG_HOTPLUG_CPU
5025
5026/*
5027 * Ensures that the idle task is using init_mm right before its cpu goes
5028 * offline.
5029 */
5030void idle_task_exit(void)
5031{
5032 struct mm_struct *mm = current->active_mm;
5033
5034 BUG_ON(cpu_online(smp_processor_id()));
5035
5036 if (mm != &init_mm)
5037 switch_mm(mm, &init_mm, current);
5038 mmdrop(mm);
5039}
5040
5041/*
5042 * While a dead CPU has no uninterruptible tasks queued at this point,
5043 * it might still have a nonzero ->nr_uninterruptible counter, because
5044 * for performance reasons the counter is not stricly tracking tasks to
5045 * their home CPUs. So we just add the counter to another CPU's counter,
5046 * to keep the global sum constant after CPU-down:
5047 */
5048static void migrate_nr_uninterruptible(struct rq *rq_src)
5049{
5050 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
5051
5052 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5053 rq_src->nr_uninterruptible = 0;
5054}
5055
5056/*
5057 * remove the tasks which were accounted by rq from calc_load_tasks.
5058 */
5059static void calc_global_load_remove(struct rq *rq)
5060{
5061 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
5062 rq->calc_load_active = 0;
5063}
5064
5065/*
5066 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5067 * try_to_wake_up()->select_task_rq().
5068 *
5069 * Called with rq->lock held even though we'er in stop_machine() and
5070 * there's no concurrency possible, we hold the required locks anyway
5071 * because of lock validation efforts.
5072 */
5073static void migrate_tasks(unsigned int dead_cpu)
5074{
5075 struct rq *rq = cpu_rq(dead_cpu);
5076 struct task_struct *next, *stop = rq->stop;
5077 int dest_cpu;
5078
5079 /*
5080 * Fudge the rq selection such that the below task selection loop
5081 * doesn't get stuck on the currently eligible stop task.
5082 *
5083 * We're currently inside stop_machine() and the rq is either stuck
5084 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5085 * either way we should never end up calling schedule() until we're
5086 * done here.
5087 */
5088 rq->stop = NULL;
5089
5090 /* Ensure any throttled groups are reachable by pick_next_task */
5091 unthrottle_offline_cfs_rqs(rq);
5092
5093 for ( ; ; ) {
5094 /*
5095 * There's this thread running, bail when that's the only
5096 * remaining thread.
5097 */
5098 if (rq->nr_running == 1)
5099 break;
5100
5101 next = pick_next_task(rq);
5102 BUG_ON(!next);
5103 next->sched_class->put_prev_task(rq, next);
5104
5105 /* Find suitable destination for @next, with force if needed. */
5106 dest_cpu = select_fallback_rq(dead_cpu, next);
5107 raw_spin_unlock(&rq->lock);
5108
5109 __migrate_task(next, dead_cpu, dest_cpu);
5110
5111 raw_spin_lock(&rq->lock);
5112 }
5113
5114 rq->stop = stop;
5115}
5116
5117#endif /* CONFIG_HOTPLUG_CPU */
5118
5119#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5120
5121static struct ctl_table sd_ctl_dir[] = {
5122 {
5123 .procname = "sched_domain",
5124 .mode = 0555,
5125 },
5126 {}
5127};
5128
5129static struct ctl_table sd_ctl_root[] = {
5130 {
5131 .procname = "kernel",
5132 .mode = 0555,
5133 .child = sd_ctl_dir,
5134 },
5135 {}
5136};
5137
5138static struct ctl_table *sd_alloc_ctl_entry(int n)
5139{
5140 struct ctl_table *entry =
5141 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5142
5143 return entry;
5144}
5145
5146static void sd_free_ctl_entry(struct ctl_table **tablep)
5147{
5148 struct ctl_table *entry;
5149
5150 /*
5151 * In the intermediate directories, both the child directory and
5152 * procname are dynamically allocated and could fail but the mode
5153 * will always be set. In the lowest directory the names are
5154 * static strings and all have proc handlers.
5155 */
5156 for (entry = *tablep; entry->mode; entry++) {
5157 if (entry->child)
5158 sd_free_ctl_entry(&entry->child);
5159 if (entry->proc_handler == NULL)
5160 kfree(entry->procname);
5161 }
5162
5163 kfree(*tablep);
5164 *tablep = NULL;
5165}
5166
5167static void
5168set_table_entry(struct ctl_table *entry,
5169 const char *procname, void *data, int maxlen,
5170 mode_t mode, proc_handler *proc_handler)
5171{
5172 entry->procname = procname;
5173 entry->data = data;
5174 entry->maxlen = maxlen;
5175 entry->mode = mode;
5176 entry->proc_handler = proc_handler;
5177}
5178
5179static struct ctl_table *
5180sd_alloc_ctl_domain_table(struct sched_domain *sd)
5181{
5182 struct ctl_table *table = sd_alloc_ctl_entry(13);
5183
5184 if (table == NULL)
5185 return NULL;
5186
5187 set_table_entry(&table[0], "min_interval", &sd->min_interval,
5188 sizeof(long), 0644, proc_doulongvec_minmax);
5189 set_table_entry(&table[1], "max_interval", &sd->max_interval,
5190 sizeof(long), 0644, proc_doulongvec_minmax);
5191 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5192 sizeof(int), 0644, proc_dointvec_minmax);
5193 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5194 sizeof(int), 0644, proc_dointvec_minmax);
5195 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5196 sizeof(int), 0644, proc_dointvec_minmax);
5197 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5198 sizeof(int), 0644, proc_dointvec_minmax);
5199 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5200 sizeof(int), 0644, proc_dointvec_minmax);
5201 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5202 sizeof(int), 0644, proc_dointvec_minmax);
5203 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5204 sizeof(int), 0644, proc_dointvec_minmax);
5205 set_table_entry(&table[9], "cache_nice_tries",
5206 &sd->cache_nice_tries,
5207 sizeof(int), 0644, proc_dointvec_minmax);
5208 set_table_entry(&table[10], "flags", &sd->flags,
5209 sizeof(int), 0644, proc_dointvec_minmax);
5210 set_table_entry(&table[11], "name", sd->name,
5211 CORENAME_MAX_SIZE, 0444, proc_dostring);
5212 /* &table[12] is terminator */
5213
5214 return table;
5215}
5216
5217static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5218{
5219 struct ctl_table *entry, *table;
5220 struct sched_domain *sd;
5221 int domain_num = 0, i;
5222 char buf[32];
5223
5224 for_each_domain(cpu, sd)
5225 domain_num++;
5226 entry = table = sd_alloc_ctl_entry(domain_num + 1);
5227 if (table == NULL)
5228 return NULL;
5229
5230 i = 0;
5231 for_each_domain(cpu, sd) {
5232 snprintf(buf, 32, "domain%d", i);
5233 entry->procname = kstrdup(buf, GFP_KERNEL);
5234 entry->mode = 0555;
5235 entry->child = sd_alloc_ctl_domain_table(sd);
5236 entry++;
5237 i++;
5238 }
5239 return table;
5240}
5241
5242static struct ctl_table_header *sd_sysctl_header;
5243static void register_sched_domain_sysctl(void)
5244{
5245 int i, cpu_num = num_possible_cpus();
5246 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5247 char buf[32];
5248
5249 WARN_ON(sd_ctl_dir[0].child);
5250 sd_ctl_dir[0].child = entry;
5251
5252 if (entry == NULL)
5253 return;
5254
5255 for_each_possible_cpu(i) {
5256 snprintf(buf, 32, "cpu%d", i);
5257 entry->procname = kstrdup(buf, GFP_KERNEL);
5258 entry->mode = 0555;
5259 entry->child = sd_alloc_ctl_cpu_table(i);
5260 entry++;
5261 }
5262
5263 WARN_ON(sd_sysctl_header);
5264 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5265}
5266
5267/* may be called multiple times per register */
5268static void unregister_sched_domain_sysctl(void)
5269{
5270 if (sd_sysctl_header)
5271 unregister_sysctl_table(sd_sysctl_header);
5272 sd_sysctl_header = NULL;
5273 if (sd_ctl_dir[0].child)
5274 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5275}
5276#else
5277static void register_sched_domain_sysctl(void)
5278{
5279}
5280static void unregister_sched_domain_sysctl(void)
5281{
5282}
5283#endif
5284
5285static void set_rq_online(struct rq *rq)
5286{
5287 if (!rq->online) {
5288 const struct sched_class *class;
5289
5290 cpumask_set_cpu(rq->cpu, rq->rd->online);
5291 rq->online = 1;
5292
5293 for_each_class(class) {
5294 if (class->rq_online)
5295 class->rq_online(rq);
5296 }
5297 }
5298}
5299
5300static void set_rq_offline(struct rq *rq)
5301{
5302 if (rq->online) {
5303 const struct sched_class *class;
5304
5305 for_each_class(class) {
5306 if (class->rq_offline)
5307 class->rq_offline(rq);
5308 }
5309
5310 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5311 rq->online = 0;
5312 }
5313}
5314
5315/*
5316 * migration_call - callback that gets triggered when a CPU is added.
5317 * Here we can start up the necessary migration thread for the new CPU.
5318 */
5319static int __cpuinit
5320migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5321{
5322 int cpu = (long)hcpu;
5323 unsigned long flags;
5324 struct rq *rq = cpu_rq(cpu);
5325
5326 switch (action & ~CPU_TASKS_FROZEN) {
5327
5328 case CPU_UP_PREPARE:
5329 rq->calc_load_update = calc_load_update;
5330 break;
5331
5332 case CPU_ONLINE:
5333 /* Update our root-domain */
5334 raw_spin_lock_irqsave(&rq->lock, flags);
5335 if (rq->rd) {
5336 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5337
5338 set_rq_online(rq);
5339 }
5340 raw_spin_unlock_irqrestore(&rq->lock, flags);
5341 break;
5342
5343#ifdef CONFIG_HOTPLUG_CPU
5344 case CPU_DYING:
5345 sched_ttwu_pending();
5346 /* Update our root-domain */
5347 raw_spin_lock_irqsave(&rq->lock, flags);
5348 if (rq->rd) {
5349 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5350 set_rq_offline(rq);
5351 }
5352 migrate_tasks(cpu);
5353 BUG_ON(rq->nr_running != 1); /* the migration thread */
5354 raw_spin_unlock_irqrestore(&rq->lock, flags);
5355
5356 migrate_nr_uninterruptible(rq);
5357 calc_global_load_remove(rq);
5358 break;
5359#endif
5360 }
5361
5362 update_max_interval();
5363
5364 return NOTIFY_OK;
5365}
5366
5367/*
5368 * Register at high priority so that task migration (migrate_all_tasks)
5369 * happens before everything else. This has to be lower priority than
5370 * the notifier in the perf_event subsystem, though.
5371 */
5372static struct notifier_block __cpuinitdata migration_notifier = {
5373 .notifier_call = migration_call,
5374 .priority = CPU_PRI_MIGRATION,
5375};
5376
5377static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
5378 unsigned long action, void *hcpu)
5379{
5380 switch (action & ~CPU_TASKS_FROZEN) {
5381 case CPU_ONLINE:
5382 case CPU_DOWN_FAILED:
5383 set_cpu_active((long)hcpu, true);
5384 return NOTIFY_OK;
5385 default:
5386 return NOTIFY_DONE;
5387 }
5388}
5389
5390static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
5391 unsigned long action, void *hcpu)
5392{
5393 switch (action & ~CPU_TASKS_FROZEN) {
5394 case CPU_DOWN_PREPARE:
5395 set_cpu_active((long)hcpu, false);
5396 return NOTIFY_OK;
5397 default:
5398 return NOTIFY_DONE;
5399 }
5400}
5401
5402static int __init migration_init(void)
5403{
5404 void *cpu = (void *)(long)smp_processor_id();
5405 int err;
5406
5407 /* Initialize migration for the boot CPU */
5408 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5409 BUG_ON(err == NOTIFY_BAD);
5410 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5411 register_cpu_notifier(&migration_notifier);
5412
5413 /* Register cpu active notifiers */
5414 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
5415 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
5416
5417 return 0;
5418}
5419early_initcall(migration_init);
5420#endif
5421
5422#ifdef CONFIG_SMP
5423
5424static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
5425
5426#ifdef CONFIG_SCHED_DEBUG
5427
5428static __read_mostly int sched_domain_debug_enabled;
5429
5430static int __init sched_domain_debug_setup(char *str)
5431{
5432 sched_domain_debug_enabled = 1;
5433
5434 return 0;
5435}
5436early_param("sched_debug", sched_domain_debug_setup);
5437
5438static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5439 struct cpumask *groupmask)
5440{
5441 struct sched_group *group = sd->groups;
5442 char str[256];
5443
5444 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5445 cpumask_clear(groupmask);
5446
5447 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5448
5449 if (!(sd->flags & SD_LOAD_BALANCE)) {
5450 printk("does not load-balance\n");
5451 if (sd->parent)
5452 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5453 " has parent");
5454 return -1;
5455 }
5456
5457 printk(KERN_CONT "span %s level %s\n", str, sd->name);
5458
5459 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5460 printk(KERN_ERR "ERROR: domain->span does not contain "
5461 "CPU%d\n", cpu);
5462 }
5463 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5464 printk(KERN_ERR "ERROR: domain->groups does not contain"
5465 " CPU%d\n", cpu);
5466 }
5467
5468 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5469 do {
5470 if (!group) {
5471 printk("\n");
5472 printk(KERN_ERR "ERROR: group is NULL\n");
5473 break;
5474 }
5475
5476 if (!group->sgp->power) {
5477 printk(KERN_CONT "\n");
5478 printk(KERN_ERR "ERROR: domain->cpu_power not "
5479 "set\n");
5480 break;
5481 }
5482
5483 if (!cpumask_weight(sched_group_cpus(group))) {
5484 printk(KERN_CONT "\n");
5485 printk(KERN_ERR "ERROR: empty group\n");
5486 break;
5487 }
5488
5489 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
5490 printk(KERN_CONT "\n");
5491 printk(KERN_ERR "ERROR: repeated CPUs\n");
5492 break;
5493 }
5494
5495 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
5496
5497 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
5498
5499 printk(KERN_CONT " %s", str);
5500 if (group->sgp->power != SCHED_POWER_SCALE) {
5501 printk(KERN_CONT " (cpu_power = %d)",
5502 group->sgp->power);
5503 }
5504
5505 group = group->next;
5506 } while (group != sd->groups);
5507 printk(KERN_CONT "\n");
5508
5509 if (!cpumask_equal(sched_domain_span(sd), groupmask))
5510 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
5511
5512 if (sd->parent &&
5513 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
5514 printk(KERN_ERR "ERROR: parent span is not a superset "
5515 "of domain->span\n");
5516 return 0;
5517}
5518
5519static void sched_domain_debug(struct sched_domain *sd, int cpu)
5520{
5521 int level = 0;
5522
5523 if (!sched_domain_debug_enabled)
5524 return;
5525
5526 if (!sd) {
5527 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5528 return;
5529 }
5530
5531 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5532
5533 for (;;) {
5534 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
5535 break;
5536 level++;
5537 sd = sd->parent;
5538 if (!sd)
5539 break;
5540 }
5541}
5542#else /* !CONFIG_SCHED_DEBUG */
5543# define sched_domain_debug(sd, cpu) do { } while (0)
5544#endif /* CONFIG_SCHED_DEBUG */
5545
5546static int sd_degenerate(struct sched_domain *sd)
5547{
5548 if (cpumask_weight(sched_domain_span(sd)) == 1)
5549 return 1;
5550
5551 /* Following flags need at least 2 groups */
5552 if (sd->flags & (SD_LOAD_BALANCE |
5553 SD_BALANCE_NEWIDLE |
5554 SD_BALANCE_FORK |
5555 SD_BALANCE_EXEC |
5556 SD_SHARE_CPUPOWER |
5557 SD_SHARE_PKG_RESOURCES)) {
5558 if (sd->groups != sd->groups->next)
5559 return 0;
5560 }
5561
5562 /* Following flags don't use groups */
5563 if (sd->flags & (SD_WAKE_AFFINE))
5564 return 0;
5565
5566 return 1;
5567}
5568
5569static int
5570sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5571{
5572 unsigned long cflags = sd->flags, pflags = parent->flags;
5573
5574 if (sd_degenerate(parent))
5575 return 1;
5576
5577 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5578 return 0;
5579
5580 /* Flags needing groups don't count if only 1 group in parent */
5581 if (parent->groups == parent->groups->next) {
5582 pflags &= ~(SD_LOAD_BALANCE |
5583 SD_BALANCE_NEWIDLE |
5584 SD_BALANCE_FORK |
5585 SD_BALANCE_EXEC |
5586 SD_SHARE_CPUPOWER |
5587 SD_SHARE_PKG_RESOURCES);
5588 if (nr_node_ids == 1)
5589 pflags &= ~SD_SERIALIZE;
5590 }
5591 if (~cflags & pflags)
5592 return 0;
5593
5594 return 1;
5595}
5596
5597static void free_rootdomain(struct rcu_head *rcu)
5598{
5599 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5600
5601 cpupri_cleanup(&rd->cpupri);
5602 free_cpumask_var(rd->rto_mask);
5603 free_cpumask_var(rd->online);
5604 free_cpumask_var(rd->span);
5605 kfree(rd);
5606}
5607
5608static void rq_attach_root(struct rq *rq, struct root_domain *rd)
5609{
5610 struct root_domain *old_rd = NULL;
5611 unsigned long flags;
5612
5613 raw_spin_lock_irqsave(&rq->lock, flags);
5614
5615 if (rq->rd) {
5616 old_rd = rq->rd;
5617
5618 if (cpumask_test_cpu(rq->cpu, old_rd->online))
5619 set_rq_offline(rq);
5620
5621 cpumask_clear_cpu(rq->cpu, old_rd->span);
5622
5623 /*
5624 * If we dont want to free the old_rt yet then
5625 * set old_rd to NULL to skip the freeing later
5626 * in this function:
5627 */
5628 if (!atomic_dec_and_test(&old_rd->refcount))
5629 old_rd = NULL;
5630 }
5631
5632 atomic_inc(&rd->refcount);
5633 rq->rd = rd;
5634
5635 cpumask_set_cpu(rq->cpu, rd->span);
5636 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5637 set_rq_online(rq);
5638
5639 raw_spin_unlock_irqrestore(&rq->lock, flags);
5640
5641 if (old_rd)
5642 call_rcu_sched(&old_rd->rcu, free_rootdomain);
5643}
5644
5645static int init_rootdomain(struct root_domain *rd)
5646{
5647 memset(rd, 0, sizeof(*rd));
5648
5649 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
5650 goto out;
5651 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
5652 goto free_span;
5653 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5654 goto free_online;
5655
5656 if (cpupri_init(&rd->cpupri) != 0)
5657 goto free_rto_mask;
5658 return 0;
5659
5660free_rto_mask:
5661 free_cpumask_var(rd->rto_mask);
5662free_online:
5663 free_cpumask_var(rd->online);
5664free_span:
5665 free_cpumask_var(rd->span);
5666out:
5667 return -ENOMEM;
5668}
5669
5670/*
5671 * By default the system creates a single root-domain with all cpus as
5672 * members (mimicking the global state we have today).
5673 */
5674struct root_domain def_root_domain;
5675
5676static void init_defrootdomain(void)
5677{
5678 init_rootdomain(&def_root_domain);
5679
5680 atomic_set(&def_root_domain.refcount, 1);
5681}
5682
5683static struct root_domain *alloc_rootdomain(void)
5684{
5685 struct root_domain *rd;
5686
5687 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5688 if (!rd)
5689 return NULL;
5690
5691 if (init_rootdomain(rd) != 0) {
5692 kfree(rd);
5693 return NULL;
5694 }
5695
5696 return rd;
5697}
5698
5699static void free_sched_groups(struct sched_group *sg, int free_sgp)
5700{
5701 struct sched_group *tmp, *first;
5702
5703 if (!sg)
5704 return;
5705
5706 first = sg;
5707 do {
5708 tmp = sg->next;
5709
5710 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
5711 kfree(sg->sgp);
5712
5713 kfree(sg);
5714 sg = tmp;
5715 } while (sg != first);
5716}
5717
5718static void free_sched_domain(struct rcu_head *rcu)
5719{
5720 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
5721
5722 /*
5723 * If its an overlapping domain it has private groups, iterate and
5724 * nuke them all.
5725 */
5726 if (sd->flags & SD_OVERLAP) {
5727 free_sched_groups(sd->groups, 1);
5728 } else if (atomic_dec_and_test(&sd->groups->ref)) {
5729 kfree(sd->groups->sgp);
5730 kfree(sd->groups);
5731 }
5732 kfree(sd);
5733}
5734
5735static void destroy_sched_domain(struct sched_domain *sd, int cpu)
5736{
5737 call_rcu(&sd->rcu, free_sched_domain);
5738}
5739
5740static void destroy_sched_domains(struct sched_domain *sd, int cpu)
5741{
5742 for (; sd; sd = sd->parent)
5743 destroy_sched_domain(sd, cpu);
5744}
5745
5746/*
5747 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5748 * hold the hotplug lock.
5749 */
5750static void
5751cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
5752{
5753 struct rq *rq = cpu_rq(cpu);
5754 struct sched_domain *tmp;
5755
5756 /* Remove the sched domains which do not contribute to scheduling. */
5757 for (tmp = sd; tmp; ) {
5758 struct sched_domain *parent = tmp->parent;
5759 if (!parent)
5760 break;
5761
5762 if (sd_parent_degenerate(tmp, parent)) {
5763 tmp->parent = parent->parent;
5764 if (parent->parent)
5765 parent->parent->child = tmp;
5766 destroy_sched_domain(parent, cpu);
5767 } else
5768 tmp = tmp->parent;
5769 }
5770
5771 if (sd && sd_degenerate(sd)) {
5772 tmp = sd;
5773 sd = sd->parent;
5774 destroy_sched_domain(tmp, cpu);
5775 if (sd)
5776 sd->child = NULL;
5777 }
5778
5779 sched_domain_debug(sd, cpu);
5780
5781 rq_attach_root(rq, rd);
5782 tmp = rq->sd;
5783 rcu_assign_pointer(rq->sd, sd);
5784 destroy_sched_domains(tmp, cpu);
5785}
5786
5787/* cpus with isolated domains */
5788static cpumask_var_t cpu_isolated_map;
5789
5790/* Setup the mask of cpus configured for isolated domains */
5791static int __init isolated_cpu_setup(char *str)
5792{
5793 alloc_bootmem_cpumask_var(&cpu_isolated_map);
5794 cpulist_parse(str, cpu_isolated_map);
5795 return 1;
5796}
5797
5798__setup("isolcpus=", isolated_cpu_setup);
5799
5800#ifdef CONFIG_NUMA
5801
5802/**
5803 * find_next_best_node - find the next node to include in a sched_domain
5804 * @node: node whose sched_domain we're building
5805 * @used_nodes: nodes already in the sched_domain
5806 *
5807 * Find the next node to include in a given scheduling domain. Simply
5808 * finds the closest node not already in the @used_nodes map.
5809 *
5810 * Should use nodemask_t.
5811 */
5812static int find_next_best_node(int node, nodemask_t *used_nodes)
5813{
5814 int i, n, val, min_val, best_node = -1;
5815
5816 min_val = INT_MAX;
5817
5818 for (i = 0; i < nr_node_ids; i++) {
5819 /* Start at @node */
5820 n = (node + i) % nr_node_ids;
5821
5822 if (!nr_cpus_node(n))
5823 continue;
5824
5825 /* Skip already used nodes */
5826 if (node_isset(n, *used_nodes))
5827 continue;
5828
5829 /* Simple min distance search */
5830 val = node_distance(node, n);
5831
5832 if (val < min_val) {
5833 min_val = val;
5834 best_node = n;
5835 }
5836 }
5837
5838 if (best_node != -1)
5839 node_set(best_node, *used_nodes);
5840 return best_node;
5841}
5842
5843/**
5844 * sched_domain_node_span - get a cpumask for a node's sched_domain
5845 * @node: node whose cpumask we're constructing
5846 * @span: resulting cpumask
5847 *
5848 * Given a node, construct a good cpumask for its sched_domain to span. It
5849 * should be one that prevents unnecessary balancing, but also spreads tasks
5850 * out optimally.
5851 */
5852static void sched_domain_node_span(int node, struct cpumask *span)
5853{
5854 nodemask_t used_nodes;
5855 int i;
5856
5857 cpumask_clear(span);
5858 nodes_clear(used_nodes);
5859
5860 cpumask_or(span, span, cpumask_of_node(node));
5861 node_set(node, used_nodes);
5862
5863 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
5864 int next_node = find_next_best_node(node, &used_nodes);
5865 if (next_node < 0)
5866 break;
5867 cpumask_or(span, span, cpumask_of_node(next_node));
5868 }
5869}
5870
5871static const struct cpumask *cpu_node_mask(int cpu)
5872{
5873 lockdep_assert_held(&sched_domains_mutex);
5874
5875 sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask);
5876
5877 return sched_domains_tmpmask;
5878}
5879
5880static const struct cpumask *cpu_allnodes_mask(int cpu)
5881{
5882 return cpu_possible_mask;
5883}
5884#endif /* CONFIG_NUMA */
5885
5886static const struct cpumask *cpu_cpu_mask(int cpu)
5887{
5888 return cpumask_of_node(cpu_to_node(cpu));
5889}
5890
5891int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
5892
5893struct sd_data {
5894 struct sched_domain **__percpu sd;
5895 struct sched_group **__percpu sg;
5896 struct sched_group_power **__percpu sgp;
5897};
5898
5899struct s_data {
5900 struct sched_domain ** __percpu sd;
5901 struct root_domain *rd;
5902};
5903
5904enum s_alloc {
5905 sa_rootdomain,
5906 sa_sd,
5907 sa_sd_storage,
5908 sa_none,
5909};
5910
5911struct sched_domain_topology_level;
5912
5913typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
5914typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
5915
5916#define SDTL_OVERLAP 0x01
5917
5918struct sched_domain_topology_level {
5919 sched_domain_init_f init;
5920 sched_domain_mask_f mask;
5921 int flags;
5922 struct sd_data data;
5923};
5924
5925static int
5926build_overlap_sched_groups(struct sched_domain *sd, int cpu)
5927{
5928 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
5929 const struct cpumask *span = sched_domain_span(sd);
5930 struct cpumask *covered = sched_domains_tmpmask;
5931 struct sd_data *sdd = sd->private;
5932 struct sched_domain *child;
5933 int i;
5934
5935 cpumask_clear(covered);
5936
5937 for_each_cpu(i, span) {
5938 struct cpumask *sg_span;
5939
5940 if (cpumask_test_cpu(i, covered))
5941 continue;
5942
5943 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
5944 GFP_KERNEL, cpu_to_node(cpu));
5945
5946 if (!sg)
5947 goto fail;
5948
5949 sg_span = sched_group_cpus(sg);
5950
5951 child = *per_cpu_ptr(sdd->sd, i);
5952 if (child->child) {
5953 child = child->child;
5954 cpumask_copy(sg_span, sched_domain_span(child));
5955 } else
5956 cpumask_set_cpu(i, sg_span);
5957
5958 cpumask_or(covered, covered, sg_span);
5959
5960 sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span));
5961 atomic_inc(&sg->sgp->ref);
5962
5963 if (cpumask_test_cpu(cpu, sg_span))
5964 groups = sg;
5965
5966 if (!first)
5967 first = sg;
5968 if (last)
5969 last->next = sg;
5970 last = sg;
5971 last->next = first;
5972 }
5973 sd->groups = groups;
5974
5975 return 0;
5976
5977fail:
5978 free_sched_groups(first, 0);
5979
5980 return -ENOMEM;
5981}
5982
5983static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
5984{
5985 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
5986 struct sched_domain *child = sd->child;
5987
5988 if (child)
5989 cpu = cpumask_first(sched_domain_span(child));
5990
5991 if (sg) {
5992 *sg = *per_cpu_ptr(sdd->sg, cpu);
5993 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
5994 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
5995 }
5996
5997 return cpu;
5998}
5999
6000/*
6001 * build_sched_groups will build a circular linked list of the groups
6002 * covered by the given span, and will set each group's ->cpumask correctly,
6003 * and ->cpu_power to 0.
6004 *
6005 * Assumes the sched_domain tree is fully constructed
6006 */
6007static int
6008build_sched_groups(struct sched_domain *sd, int cpu)
6009{
6010 struct sched_group *first = NULL, *last = NULL;
6011 struct sd_data *sdd = sd->private;
6012 const struct cpumask *span = sched_domain_span(sd);
6013 struct cpumask *covered;
6014 int i;
6015
6016 get_group(cpu, sdd, &sd->groups);
6017 atomic_inc(&sd->groups->ref);
6018
6019 if (cpu != cpumask_first(sched_domain_span(sd)))
6020 return 0;
6021
6022 lockdep_assert_held(&sched_domains_mutex);
6023 covered = sched_domains_tmpmask;
6024
6025 cpumask_clear(covered);
6026
6027 for_each_cpu(i, span) {
6028 struct sched_group *sg;
6029 int group = get_group(i, sdd, &sg);
6030 int j;
6031
6032 if (cpumask_test_cpu(i, covered))
6033 continue;
6034
6035 cpumask_clear(sched_group_cpus(sg));
6036 sg->sgp->power = 0;
6037
6038 for_each_cpu(j, span) {
6039 if (get_group(j, sdd, NULL) != group)
6040 continue;
6041
6042 cpumask_set_cpu(j, covered);
6043 cpumask_set_cpu(j, sched_group_cpus(sg));
6044 }
6045
6046 if (!first)
6047 first = sg;
6048 if (last)
6049 last->next = sg;
6050 last = sg;
6051 }
6052 last->next = first;
6053
6054 return 0;
6055}
6056
6057/*
6058 * Initialize sched groups cpu_power.
6059 *
6060 * cpu_power indicates the capacity of sched group, which is used while
6061 * distributing the load between different sched groups in a sched domain.
6062 * Typically cpu_power for all the groups in a sched domain will be same unless
6063 * there are asymmetries in the topology. If there are asymmetries, group
6064 * having more cpu_power will pickup more load compared to the group having
6065 * less cpu_power.
6066 */
6067static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6068{
6069 struct sched_group *sg = sd->groups;
6070
6071 WARN_ON(!sd || !sg);
6072
6073 do {
6074 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
6075 sg = sg->next;
6076 } while (sg != sd->groups);
6077
6078 if (cpu != group_first_cpu(sg))
6079 return;
6080
6081 update_group_power(sd, cpu);
6082 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
6083}
6084
6085int __weak arch_sd_sibling_asym_packing(void)
6086{
6087 return 0*SD_ASYM_PACKING;
6088}
6089
6090/*
6091 * Initializers for schedule domains
6092 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6093 */
6094
6095#ifdef CONFIG_SCHED_DEBUG
6096# define SD_INIT_NAME(sd, type) sd->name = #type
6097#else
6098# define SD_INIT_NAME(sd, type) do { } while (0)
6099#endif
6100
6101#define SD_INIT_FUNC(type) \
6102static noinline struct sched_domain * \
6103sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6104{ \
6105 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6106 *sd = SD_##type##_INIT; \
6107 SD_INIT_NAME(sd, type); \
6108 sd->private = &tl->data; \
6109 return sd; \
6110}
6111
6112SD_INIT_FUNC(CPU)
6113#ifdef CONFIG_NUMA
6114 SD_INIT_FUNC(ALLNODES)
6115 SD_INIT_FUNC(NODE)
6116#endif
6117#ifdef CONFIG_SCHED_SMT
6118 SD_INIT_FUNC(SIBLING)
6119#endif
6120#ifdef CONFIG_SCHED_MC
6121 SD_INIT_FUNC(MC)
6122#endif
6123#ifdef CONFIG_SCHED_BOOK
6124 SD_INIT_FUNC(BOOK)
6125#endif
6126
6127static int default_relax_domain_level = -1;
6128int sched_domain_level_max;
6129
6130static int __init setup_relax_domain_level(char *str)
6131{
6132 unsigned long val;
6133
6134 val = simple_strtoul(str, NULL, 0);
6135 if (val < sched_domain_level_max)
6136 default_relax_domain_level = val;
6137
6138 return 1;
6139}
6140__setup("relax_domain_level=", setup_relax_domain_level);
6141
6142static void set_domain_attribute(struct sched_domain *sd,
6143 struct sched_domain_attr *attr)
6144{
6145 int request;
6146
6147 if (!attr || attr->relax_domain_level < 0) {
6148 if (default_relax_domain_level < 0)
6149 return;
6150 else
6151 request = default_relax_domain_level;
6152 } else
6153 request = attr->relax_domain_level;
6154 if (request < sd->level) {
6155 /* turn off idle balance on this domain */
6156 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6157 } else {
6158 /* turn on idle balance on this domain */
6159 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6160 }
6161}
6162
6163static void __sdt_free(const struct cpumask *cpu_map);
6164static int __sdt_alloc(const struct cpumask *cpu_map);
6165
6166static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6167 const struct cpumask *cpu_map)
6168{
6169 switch (what) {
6170 case sa_rootdomain:
6171 if (!atomic_read(&d->rd->refcount))
6172 free_rootdomain(&d->rd->rcu); /* fall through */
6173 case sa_sd:
6174 free_percpu(d->sd); /* fall through */
6175 case sa_sd_storage:
6176 __sdt_free(cpu_map); /* fall through */
6177 case sa_none:
6178 break;
6179 }
6180}
6181
6182static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6183 const struct cpumask *cpu_map)
6184{
6185 memset(d, 0, sizeof(*d));
6186
6187 if (__sdt_alloc(cpu_map))
6188 return sa_sd_storage;
6189 d->sd = alloc_percpu(struct sched_domain *);
6190 if (!d->sd)
6191 return sa_sd_storage;
6192 d->rd = alloc_rootdomain();
6193 if (!d->rd)
6194 return sa_sd;
6195 return sa_rootdomain;
6196}
6197
6198/*
6199 * NULL the sd_data elements we've used to build the sched_domain and
6200 * sched_group structure so that the subsequent __free_domain_allocs()
6201 * will not free the data we're using.
6202 */
6203static void claim_allocations(int cpu, struct sched_domain *sd)
6204{
6205 struct sd_data *sdd = sd->private;
6206
6207 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
6208 *per_cpu_ptr(sdd->sd, cpu) = NULL;
6209
6210 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6211 *per_cpu_ptr(sdd->sg, cpu) = NULL;
6212
6213 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
6214 *per_cpu_ptr(sdd->sgp, cpu) = NULL;
6215}
6216
6217#ifdef CONFIG_SCHED_SMT
6218static const struct cpumask *cpu_smt_mask(int cpu)
6219{
6220 return topology_thread_cpumask(cpu);
6221}
6222#endif
6223
6224/*
6225 * Topology list, bottom-up.
6226 */
6227static struct sched_domain_topology_level default_topology[] = {
6228#ifdef CONFIG_SCHED_SMT
6229 { sd_init_SIBLING, cpu_smt_mask, },
6230#endif
6231#ifdef CONFIG_SCHED_MC
6232 { sd_init_MC, cpu_coregroup_mask, },
6233#endif
6234#ifdef CONFIG_SCHED_BOOK
6235 { sd_init_BOOK, cpu_book_mask, },
6236#endif
6237 { sd_init_CPU, cpu_cpu_mask, },
6238#ifdef CONFIG_NUMA
6239 { sd_init_NODE, cpu_node_mask, SDTL_OVERLAP, },
6240 { sd_init_ALLNODES, cpu_allnodes_mask, },
6241#endif
6242 { NULL, },
6243};
6244
6245static struct sched_domain_topology_level *sched_domain_topology = default_topology;
6246
6247static int __sdt_alloc(const struct cpumask *cpu_map)
6248{
6249 struct sched_domain_topology_level *tl;
6250 int j;
6251
6252 for (tl = sched_domain_topology; tl->init; tl++) {
6253 struct sd_data *sdd = &tl->data;
6254
6255 sdd->sd = alloc_percpu(struct sched_domain *);
6256 if (!sdd->sd)
6257 return -ENOMEM;
6258
6259 sdd->sg = alloc_percpu(struct sched_group *);
6260 if (!sdd->sg)
6261 return -ENOMEM;
6262
6263 sdd->sgp = alloc_percpu(struct sched_group_power *);
6264 if (!sdd->sgp)
6265 return -ENOMEM;
6266
6267 for_each_cpu(j, cpu_map) {
6268 struct sched_domain *sd;
6269 struct sched_group *sg;
6270 struct sched_group_power *sgp;
6271
6272 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
6273 GFP_KERNEL, cpu_to_node(j));
6274 if (!sd)
6275 return -ENOMEM;
6276
6277 *per_cpu_ptr(sdd->sd, j) = sd;
6278
6279 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6280 GFP_KERNEL, cpu_to_node(j));
6281 if (!sg)
6282 return -ENOMEM;
6283
6284 *per_cpu_ptr(sdd->sg, j) = sg;
6285
6286 sgp = kzalloc_node(sizeof(struct sched_group_power),
6287 GFP_KERNEL, cpu_to_node(j));
6288 if (!sgp)
6289 return -ENOMEM;
6290
6291 *per_cpu_ptr(sdd->sgp, j) = sgp;
6292 }
6293 }
6294
6295 return 0;
6296}
6297
6298static void __sdt_free(const struct cpumask *cpu_map)
6299{
6300 struct sched_domain_topology_level *tl;
6301 int j;
6302
6303 for (tl = sched_domain_topology; tl->init; tl++) {
6304 struct sd_data *sdd = &tl->data;
6305
6306 for_each_cpu(j, cpu_map) {
6307 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j);
6308 if (sd && (sd->flags & SD_OVERLAP))
6309 free_sched_groups(sd->groups, 0);
6310 kfree(*per_cpu_ptr(sdd->sd, j));
6311 kfree(*per_cpu_ptr(sdd->sg, j));
6312 kfree(*per_cpu_ptr(sdd->sgp, j));
6313 }
6314 free_percpu(sdd->sd);
6315 free_percpu(sdd->sg);
6316 free_percpu(sdd->sgp);
6317 }
6318}
6319
6320struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
6321 struct s_data *d, const struct cpumask *cpu_map,
6322 struct sched_domain_attr *attr, struct sched_domain *child,
6323 int cpu)
6324{
6325 struct sched_domain *sd = tl->init(tl, cpu);
6326 if (!sd)
6327 return child;
6328
6329 set_domain_attribute(sd, attr);
6330 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6331 if (child) {
6332 sd->level = child->level + 1;
6333 sched_domain_level_max = max(sched_domain_level_max, sd->level);
6334 child->parent = sd;
6335 }
6336 sd->child = child;
6337
6338 return sd;
6339}
6340
6341/*
6342 * Build sched domains for a given set of cpus and attach the sched domains
6343 * to the individual cpus
6344 */
6345static int build_sched_domains(const struct cpumask *cpu_map,
6346 struct sched_domain_attr *attr)
6347{
6348 enum s_alloc alloc_state = sa_none;
6349 struct sched_domain *sd;
6350 struct s_data d;
6351 int i, ret = -ENOMEM;
6352
6353 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6354 if (alloc_state != sa_rootdomain)
6355 goto error;
6356
6357 /* Set up domains for cpus specified by the cpu_map. */
6358 for_each_cpu(i, cpu_map) {
6359 struct sched_domain_topology_level *tl;
6360
6361 sd = NULL;
6362 for (tl = sched_domain_topology; tl->init; tl++) {
6363 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
6364 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6365 sd->flags |= SD_OVERLAP;
6366 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6367 break;
6368 }
6369
6370 while (sd->child)
6371 sd = sd->child;
6372
6373 *per_cpu_ptr(d.sd, i) = sd;
6374 }
6375
6376 /* Build the groups for the domains */
6377 for_each_cpu(i, cpu_map) {
6378 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6379 sd->span_weight = cpumask_weight(sched_domain_span(sd));
6380 if (sd->flags & SD_OVERLAP) {
6381 if (build_overlap_sched_groups(sd, i))
6382 goto error;
6383 } else {
6384 if (build_sched_groups(sd, i))
6385 goto error;
6386 }
6387 }
6388 }
6389
6390 /* Calculate CPU power for physical packages and nodes */
6391 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6392 if (!cpumask_test_cpu(i, cpu_map))
6393 continue;
6394
6395 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6396 claim_allocations(i, sd);
6397 init_sched_groups_power(i, sd);
6398 }
6399 }
6400
6401 /* Attach the domains */
6402 rcu_read_lock();
6403 for_each_cpu(i, cpu_map) {
6404 sd = *per_cpu_ptr(d.sd, i);
6405 cpu_attach_domain(sd, d.rd, i);
6406 }
6407 rcu_read_unlock();
6408
6409 ret = 0;
6410error:
6411 __free_domain_allocs(&d, alloc_state, cpu_map);
6412 return ret;
6413}
6414
6415static cpumask_var_t *doms_cur; /* current sched domains */
6416static int ndoms_cur; /* number of sched domains in 'doms_cur' */
6417static struct sched_domain_attr *dattr_cur;
6418 /* attribues of custom domains in 'doms_cur' */
6419
6420/*
6421 * Special case: If a kmalloc of a doms_cur partition (array of
6422 * cpumask) fails, then fallback to a single sched domain,
6423 * as determined by the single cpumask fallback_doms.
6424 */
6425static cpumask_var_t fallback_doms;
6426
6427/*
6428 * arch_update_cpu_topology lets virtualized architectures update the
6429 * cpu core maps. It is supposed to return 1 if the topology changed
6430 * or 0 if it stayed the same.
6431 */
6432int __attribute__((weak)) arch_update_cpu_topology(void)
6433{
6434 return 0;
6435}
6436
6437cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6438{
6439 int i;
6440 cpumask_var_t *doms;
6441
6442 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6443 if (!doms)
6444 return NULL;
6445 for (i = 0; i < ndoms; i++) {
6446 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6447 free_sched_domains(doms, i);
6448 return NULL;
6449 }
6450 }
6451 return doms;
6452}
6453
6454void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6455{
6456 unsigned int i;
6457 for (i = 0; i < ndoms; i++)
6458 free_cpumask_var(doms[i]);
6459 kfree(doms);
6460}
6461
6462/*
6463 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6464 * For now this just excludes isolated cpus, but could be used to
6465 * exclude other special cases in the future.
6466 */
6467static int init_sched_domains(const struct cpumask *cpu_map)
6468{
6469 int err;
6470
6471 arch_update_cpu_topology();
6472 ndoms_cur = 1;
6473 doms_cur = alloc_sched_domains(ndoms_cur);
6474 if (!doms_cur)
6475 doms_cur = &fallback_doms;
6476 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6477 dattr_cur = NULL;
6478 err = build_sched_domains(doms_cur[0], NULL);
6479 register_sched_domain_sysctl();
6480
6481 return err;
6482}
6483
6484/*
6485 * Detach sched domains from a group of cpus specified in cpu_map
6486 * These cpus will now be attached to the NULL domain
6487 */
6488static void detach_destroy_domains(const struct cpumask *cpu_map)
6489{
6490 int i;
6491
6492 rcu_read_lock();
6493 for_each_cpu(i, cpu_map)
6494 cpu_attach_domain(NULL, &def_root_domain, i);
6495 rcu_read_unlock();
6496}
6497
6498/* handle null as "default" */
6499static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6500 struct sched_domain_attr *new, int idx_new)
6501{
6502 struct sched_domain_attr tmp;
6503
6504 /* fast path */
6505 if (!new && !cur)
6506 return 1;
6507
6508 tmp = SD_ATTR_INIT;
6509 return !memcmp(cur ? (cur + idx_cur) : &tmp,
6510 new ? (new + idx_new) : &tmp,
6511 sizeof(struct sched_domain_attr));
6512}
6513
6514/*
6515 * Partition sched domains as specified by the 'ndoms_new'
6516 * cpumasks in the array doms_new[] of cpumasks. This compares
6517 * doms_new[] to the current sched domain partitioning, doms_cur[].
6518 * It destroys each deleted domain and builds each new domain.
6519 *
6520 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6521 * The masks don't intersect (don't overlap.) We should setup one
6522 * sched domain for each mask. CPUs not in any of the cpumasks will
6523 * not be load balanced. If the same cpumask appears both in the
6524 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6525 * it as it is.
6526 *
6527 * The passed in 'doms_new' should be allocated using
6528 * alloc_sched_domains. This routine takes ownership of it and will
6529 * free_sched_domains it when done with it. If the caller failed the
6530 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6531 * and partition_sched_domains() will fallback to the single partition
6532 * 'fallback_doms', it also forces the domains to be rebuilt.
6533 *
6534 * If doms_new == NULL it will be replaced with cpu_online_mask.
6535 * ndoms_new == 0 is a special case for destroying existing domains,
6536 * and it will not create the default domain.
6537 *
6538 * Call with hotplug lock held
6539 */
6540void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
6541 struct sched_domain_attr *dattr_new)
6542{
6543 int i, j, n;
6544 int new_topology;
6545
6546 mutex_lock(&sched_domains_mutex);
6547
6548 /* always unregister in case we don't destroy any domains */
6549 unregister_sched_domain_sysctl();
6550
6551 /* Let architecture update cpu core mappings. */
6552 new_topology = arch_update_cpu_topology();
6553
6554 n = doms_new ? ndoms_new : 0;
6555
6556 /* Destroy deleted domains */
6557 for (i = 0; i < ndoms_cur; i++) {
6558 for (j = 0; j < n && !new_topology; j++) {
6559 if (cpumask_equal(doms_cur[i], doms_new[j])
6560 && dattrs_equal(dattr_cur, i, dattr_new, j))
6561 goto match1;
6562 }
6563 /* no match - a current sched domain not in new doms_new[] */
6564 detach_destroy_domains(doms_cur[i]);
6565match1:
6566 ;
6567 }
6568
6569 if (doms_new == NULL) {
6570 ndoms_cur = 0;
6571 doms_new = &fallback_doms;
6572 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
6573 WARN_ON_ONCE(dattr_new);
6574 }
6575
6576 /* Build new domains */
6577 for (i = 0; i < ndoms_new; i++) {
6578 for (j = 0; j < ndoms_cur && !new_topology; j++) {
6579 if (cpumask_equal(doms_new[i], doms_cur[j])
6580 && dattrs_equal(dattr_new, i, dattr_cur, j))
6581 goto match2;
6582 }
6583 /* no match - add a new doms_new */
6584 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
6585match2:
6586 ;
6587 }
6588
6589 /* Remember the new sched domains */
6590 if (doms_cur != &fallback_doms)
6591 free_sched_domains(doms_cur, ndoms_cur);
6592 kfree(dattr_cur); /* kfree(NULL) is safe */
6593 doms_cur = doms_new;
6594 dattr_cur = dattr_new;
6595 ndoms_cur = ndoms_new;
6596
6597 register_sched_domain_sysctl();
6598
6599 mutex_unlock(&sched_domains_mutex);
6600}
6601
6602#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
6603static void reinit_sched_domains(void)
6604{
6605 get_online_cpus();
6606
6607 /* Destroy domains first to force the rebuild */
6608 partition_sched_domains(0, NULL, NULL);
6609
6610 rebuild_sched_domains();
6611 put_online_cpus();
6612}
6613
6614static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
6615{
6616 unsigned int level = 0;
6617
6618 if (sscanf(buf, "%u", &level) != 1)
6619 return -EINVAL;
6620
6621 /*
6622 * level is always be positive so don't check for
6623 * level < POWERSAVINGS_BALANCE_NONE which is 0
6624 * What happens on 0 or 1 byte write,
6625 * need to check for count as well?
6626 */
6627
6628 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
6629 return -EINVAL;
6630
6631 if (smt)
6632 sched_smt_power_savings = level;
6633 else
6634 sched_mc_power_savings = level;
6635
6636 reinit_sched_domains();
6637
6638 return count;
6639}
6640
6641#ifdef CONFIG_SCHED_MC
6642static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
6643 struct sysdev_class_attribute *attr,
6644 char *page)
6645{
6646 return sprintf(page, "%u\n", sched_mc_power_savings);
6647}
6648static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
6649 struct sysdev_class_attribute *attr,
6650 const char *buf, size_t count)
6651{
6652 return sched_power_savings_store(buf, count, 0);
6653}
6654static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
6655 sched_mc_power_savings_show,
6656 sched_mc_power_savings_store);
6657#endif
6658
6659#ifdef CONFIG_SCHED_SMT
6660static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
6661 struct sysdev_class_attribute *attr,
6662 char *page)
6663{
6664 return sprintf(page, "%u\n", sched_smt_power_savings);
6665}
6666static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
6667 struct sysdev_class_attribute *attr,
6668 const char *buf, size_t count)
6669{
6670 return sched_power_savings_store(buf, count, 1);
6671}
6672static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
6673 sched_smt_power_savings_show,
6674 sched_smt_power_savings_store);
6675#endif
6676
6677int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
6678{
6679 int err = 0;
6680
6681#ifdef CONFIG_SCHED_SMT
6682 if (smt_capable())
6683 err = sysfs_create_file(&cls->kset.kobj,
6684 &attr_sched_smt_power_savings.attr);
6685#endif
6686#ifdef CONFIG_SCHED_MC
6687 if (!err && mc_capable())
6688 err = sysfs_create_file(&cls->kset.kobj,
6689 &attr_sched_mc_power_savings.attr);
6690#endif
6691 return err;
6692}
6693#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
6694
6695/*
6696 * Update cpusets according to cpu_active mask. If cpusets are
6697 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6698 * around partition_sched_domains().
6699 */
6700static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
6701 void *hcpu)
6702{
6703 switch (action & ~CPU_TASKS_FROZEN) {
6704 case CPU_ONLINE:
6705 case CPU_DOWN_FAILED:
6706 cpuset_update_active_cpus();
6707 return NOTIFY_OK;
6708 default:
6709 return NOTIFY_DONE;
6710 }
6711}
6712
6713static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
6714 void *hcpu)
6715{
6716 switch (action & ~CPU_TASKS_FROZEN) {
6717 case CPU_DOWN_PREPARE:
6718 cpuset_update_active_cpus();
6719 return NOTIFY_OK;
6720 default:
6721 return NOTIFY_DONE;
6722 }
6723}
6724
6725void __init sched_init_smp(void)
6726{
6727 cpumask_var_t non_isolated_cpus;
6728
6729 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
6730 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
6731
6732 get_online_cpus();
6733 mutex_lock(&sched_domains_mutex);
6734 init_sched_domains(cpu_active_mask);
6735 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
6736 if (cpumask_empty(non_isolated_cpus))
6737 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
6738 mutex_unlock(&sched_domains_mutex);
6739 put_online_cpus();
6740
6741 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
6742 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
6743
6744 /* RT runtime code needs to handle some hotplug events */
6745 hotcpu_notifier(update_runtime, 0);
6746
6747 init_hrtick();
6748
6749 /* Move init over to a non-isolated CPU */
6750 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
6751 BUG();
6752 sched_init_granularity();
6753 free_cpumask_var(non_isolated_cpus);
6754
6755 init_sched_rt_class();
6756}
6757#else
6758void __init sched_init_smp(void)
6759{
6760 sched_init_granularity();
6761}
6762#endif /* CONFIG_SMP */
6763
6764const_debug unsigned int sysctl_timer_migration = 1;
6765
6766int in_sched_functions(unsigned long addr)
6767{
6768 return in_lock_functions(addr) ||
6769 (addr >= (unsigned long)__sched_text_start
6770 && addr < (unsigned long)__sched_text_end);
6771}
6772
6773#ifdef CONFIG_CGROUP_SCHED
6774struct task_group root_task_group;
6775#endif
6776
6777DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
6778
6779void __init sched_init(void)
6780{
6781 int i, j;
6782 unsigned long alloc_size = 0, ptr;
6783
6784#ifdef CONFIG_FAIR_GROUP_SCHED
6785 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6786#endif
6787#ifdef CONFIG_RT_GROUP_SCHED
6788 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6789#endif
6790#ifdef CONFIG_CPUMASK_OFFSTACK
6791 alloc_size += num_possible_cpus() * cpumask_size();
6792#endif
6793 if (alloc_size) {
6794 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
6795
6796#ifdef CONFIG_FAIR_GROUP_SCHED
6797 root_task_group.se = (struct sched_entity **)ptr;
6798 ptr += nr_cpu_ids * sizeof(void **);
6799
6800 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
6801 ptr += nr_cpu_ids * sizeof(void **);
6802
6803#endif /* CONFIG_FAIR_GROUP_SCHED */
6804#ifdef CONFIG_RT_GROUP_SCHED
6805 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
6806 ptr += nr_cpu_ids * sizeof(void **);
6807
6808 root_task_group.rt_rq = (struct rt_rq **)ptr;
6809 ptr += nr_cpu_ids * sizeof(void **);
6810
6811#endif /* CONFIG_RT_GROUP_SCHED */
6812#ifdef CONFIG_CPUMASK_OFFSTACK
6813 for_each_possible_cpu(i) {
6814 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
6815 ptr += cpumask_size();
6816 }
6817#endif /* CONFIG_CPUMASK_OFFSTACK */
6818 }
6819
6820#ifdef CONFIG_SMP
6821 init_defrootdomain();
6822#endif
6823
6824 init_rt_bandwidth(&def_rt_bandwidth,
6825 global_rt_period(), global_rt_runtime());
6826
6827#ifdef CONFIG_RT_GROUP_SCHED
6828 init_rt_bandwidth(&root_task_group.rt_bandwidth,
6829 global_rt_period(), global_rt_runtime());
6830#endif /* CONFIG_RT_GROUP_SCHED */
6831
6832#ifdef CONFIG_CGROUP_SCHED
6833 list_add(&root_task_group.list, &task_groups);
6834 INIT_LIST_HEAD(&root_task_group.children);
6835 INIT_LIST_HEAD(&root_task_group.siblings);
6836 autogroup_init(&init_task);
6837
6838#endif /* CONFIG_CGROUP_SCHED */
6839
6840#ifdef CONFIG_CGROUP_CPUACCT
6841 root_cpuacct.cpustat = &kernel_cpustat;
6842 root_cpuacct.cpuusage = alloc_percpu(u64);
6843 /* Too early, not expected to fail */
6844 BUG_ON(!root_cpuacct.cpuusage);
6845#endif
6846 for_each_possible_cpu(i) {
6847 struct rq *rq;
6848
6849 rq = cpu_rq(i);
6850 raw_spin_lock_init(&rq->lock);
6851 rq->nr_running = 0;
6852 rq->calc_load_active = 0;
6853 rq->calc_load_update = jiffies + LOAD_FREQ;
6854 init_cfs_rq(&rq->cfs);
6855 init_rt_rq(&rq->rt, rq);
6856#ifdef CONFIG_FAIR_GROUP_SCHED
6857 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
6858 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
6859 /*
6860 * How much cpu bandwidth does root_task_group get?
6861 *
6862 * In case of task-groups formed thr' the cgroup filesystem, it
6863 * gets 100% of the cpu resources in the system. This overall
6864 * system cpu resource is divided among the tasks of
6865 * root_task_group and its child task-groups in a fair manner,
6866 * based on each entity's (task or task-group's) weight
6867 * (se->load.weight).
6868 *
6869 * In other words, if root_task_group has 10 tasks of weight
6870 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6871 * then A0's share of the cpu resource is:
6872 *
6873 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6874 *
6875 * We achieve this by letting root_task_group's tasks sit
6876 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6877 */
6878 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
6879 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
6880#endif /* CONFIG_FAIR_GROUP_SCHED */
6881
6882 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
6883#ifdef CONFIG_RT_GROUP_SCHED
6884 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
6885 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
6886#endif
6887
6888 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
6889 rq->cpu_load[j] = 0;
6890
6891 rq->last_load_update_tick = jiffies;
6892
6893#ifdef CONFIG_SMP
6894 rq->sd = NULL;
6895 rq->rd = NULL;
6896 rq->cpu_power = SCHED_POWER_SCALE;
6897 rq->post_schedule = 0;
6898 rq->active_balance = 0;
6899 rq->next_balance = jiffies;
6900 rq->push_cpu = 0;
6901 rq->cpu = i;
6902 rq->online = 0;
6903 rq->idle_stamp = 0;
6904 rq->avg_idle = 2*sysctl_sched_migration_cost;
6905 rq_attach_root(rq, &def_root_domain);
6906#ifdef CONFIG_NO_HZ
6907 rq->nohz_flags = 0;
6908#endif
6909#endif
6910 init_rq_hrtick(rq);
6911 atomic_set(&rq->nr_iowait, 0);
6912 }
6913
6914 set_load_weight(&init_task);
6915
6916#ifdef CONFIG_PREEMPT_NOTIFIERS
6917 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
6918#endif
6919
6920#ifdef CONFIG_RT_MUTEXES
6921 plist_head_init(&init_task.pi_waiters);
6922#endif
6923
6924 /*
6925 * The boot idle thread does lazy MMU switching as well:
6926 */
6927 atomic_inc(&init_mm.mm_count);
6928 enter_lazy_tlb(&init_mm, current);
6929
6930 /*
6931 * Make us the idle thread. Technically, schedule() should not be
6932 * called from this thread, however somewhere below it might be,
6933 * but because we are the idle thread, we just pick up running again
6934 * when this runqueue becomes "idle".
6935 */
6936 init_idle(current, smp_processor_id());
6937
6938 calc_load_update = jiffies + LOAD_FREQ;
6939
6940 /*
6941 * During early bootup we pretend to be a normal task:
6942 */
6943 current->sched_class = &fair_sched_class;
6944
6945#ifdef CONFIG_SMP
6946 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
6947 /* May be allocated at isolcpus cmdline parse time */
6948 if (cpu_isolated_map == NULL)
6949 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
6950#endif
6951 init_sched_fair_class();
6952
6953 scheduler_running = 1;
6954}
6955
6956#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6957static inline int preempt_count_equals(int preempt_offset)
6958{
6959 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
6960
6961 return (nested == preempt_offset);
6962}
6963
6964void __might_sleep(const char *file, int line, int preempt_offset)
6965{
6966 static unsigned long prev_jiffy; /* ratelimiting */
6967
6968 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6969 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
6970 system_state != SYSTEM_RUNNING || oops_in_progress)
6971 return;
6972 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
6973 return;
6974 prev_jiffy = jiffies;
6975
6976 printk(KERN_ERR
6977 "BUG: sleeping function called from invalid context at %s:%d\n",
6978 file, line);
6979 printk(KERN_ERR
6980 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6981 in_atomic(), irqs_disabled(),
6982 current->pid, current->comm);
6983
6984 debug_show_held_locks(current);
6985 if (irqs_disabled())
6986 print_irqtrace_events(current);
6987 dump_stack();
6988}
6989EXPORT_SYMBOL(__might_sleep);
6990#endif
6991
6992#ifdef CONFIG_MAGIC_SYSRQ
6993static void normalize_task(struct rq *rq, struct task_struct *p)
6994{
6995 const struct sched_class *prev_class = p->sched_class;
6996 int old_prio = p->prio;
6997 int on_rq;
6998
6999 on_rq = p->on_rq;
7000 if (on_rq)
7001 deactivate_task(rq, p, 0);
7002 __setscheduler(rq, p, SCHED_NORMAL, 0);
7003 if (on_rq) {
7004 activate_task(rq, p, 0);
7005 resched_task(rq->curr);
7006 }
7007
7008 check_class_changed(rq, p, prev_class, old_prio);
7009}
7010
7011void normalize_rt_tasks(void)
7012{
7013 struct task_struct *g, *p;
7014 unsigned long flags;
7015 struct rq *rq;
7016
7017 read_lock_irqsave(&tasklist_lock, flags);
7018 do_each_thread(g, p) {
7019 /*
7020 * Only normalize user tasks:
7021 */
7022 if (!p->mm)
7023 continue;
7024
7025 p->se.exec_start = 0;
7026#ifdef CONFIG_SCHEDSTATS
7027 p->se.statistics.wait_start = 0;
7028 p->se.statistics.sleep_start = 0;
7029 p->se.statistics.block_start = 0;
7030#endif
7031
7032 if (!rt_task(p)) {
7033 /*
7034 * Renice negative nice level userspace
7035 * tasks back to 0:
7036 */
7037 if (TASK_NICE(p) < 0 && p->mm)
7038 set_user_nice(p, 0);
7039 continue;
7040 }
7041
7042 raw_spin_lock(&p->pi_lock);
7043 rq = __task_rq_lock(p);
7044
7045 normalize_task(rq, p);
7046
7047 __task_rq_unlock(rq);
7048 raw_spin_unlock(&p->pi_lock);
7049 } while_each_thread(g, p);
7050
7051 read_unlock_irqrestore(&tasklist_lock, flags);
7052}
7053
7054#endif /* CONFIG_MAGIC_SYSRQ */
7055
7056#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7057/*
7058 * These functions are only useful for the IA64 MCA handling, or kdb.
7059 *
7060 * They can only be called when the whole system has been
7061 * stopped - every CPU needs to be quiescent, and no scheduling
7062 * activity can take place. Using them for anything else would
7063 * be a serious bug, and as a result, they aren't even visible
7064 * under any other configuration.
7065 */
7066
7067/**
7068 * curr_task - return the current task for a given cpu.
7069 * @cpu: the processor in question.
7070 *
7071 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7072 */
7073struct task_struct *curr_task(int cpu)
7074{
7075 return cpu_curr(cpu);
7076}
7077
7078#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7079
7080#ifdef CONFIG_IA64
7081/**
7082 * set_curr_task - set the current task for a given cpu.
7083 * @cpu: the processor in question.
7084 * @p: the task pointer to set.
7085 *
7086 * Description: This function must only be used when non-maskable interrupts
7087 * are serviced on a separate stack. It allows the architecture to switch the
7088 * notion of the current task on a cpu in a non-blocking manner. This function
7089 * must be called with all CPU's synchronized, and interrupts disabled, the
7090 * and caller must save the original value of the current task (see
7091 * curr_task() above) and restore that value before reenabling interrupts and
7092 * re-starting the system.
7093 *
7094 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7095 */
7096void set_curr_task(int cpu, struct task_struct *p)
7097{
7098 cpu_curr(cpu) = p;
7099}
7100
7101#endif
7102
7103#ifdef CONFIG_RT_GROUP_SCHED
7104#else /* !CONFIG_RT_GROUP_SCHED */
7105#endif /* CONFIG_RT_GROUP_SCHED */
7106
7107#ifdef CONFIG_CGROUP_SCHED
7108/* task_group_lock serializes the addition/removal of task groups */
7109static DEFINE_SPINLOCK(task_group_lock);
7110
7111static void free_sched_group(struct task_group *tg)
7112{
7113 free_fair_sched_group(tg);
7114 free_rt_sched_group(tg);
7115 autogroup_free(tg);
7116 kfree(tg);
7117}
7118
7119/* allocate runqueue etc for a new task group */
7120struct task_group *sched_create_group(struct task_group *parent)
7121{
7122 struct task_group *tg;
7123 unsigned long flags;
7124
7125 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
7126 if (!tg)
7127 return ERR_PTR(-ENOMEM);
7128
7129 if (!alloc_fair_sched_group(tg, parent))
7130 goto err;
7131
7132 if (!alloc_rt_sched_group(tg, parent))
7133 goto err;
7134
7135 spin_lock_irqsave(&task_group_lock, flags);
7136 list_add_rcu(&tg->list, &task_groups);
7137
7138 WARN_ON(!parent); /* root should already exist */
7139
7140 tg->parent = parent;
7141 INIT_LIST_HEAD(&tg->children);
7142 list_add_rcu(&tg->siblings, &parent->children);
7143 spin_unlock_irqrestore(&task_group_lock, flags);
7144
7145 return tg;
7146
7147err:
7148 free_sched_group(tg);
7149 return ERR_PTR(-ENOMEM);
7150}
7151
7152/* rcu callback to free various structures associated with a task group */
7153static void free_sched_group_rcu(struct rcu_head *rhp)
7154{
7155 /* now it should be safe to free those cfs_rqs */
7156 free_sched_group(container_of(rhp, struct task_group, rcu));
7157}
7158
7159/* Destroy runqueue etc associated with a task group */
7160void sched_destroy_group(struct task_group *tg)
7161{
7162 unsigned long flags;
7163 int i;
7164
7165 /* end participation in shares distribution */
7166 for_each_possible_cpu(i)
7167 unregister_fair_sched_group(tg, i);
7168
7169 spin_lock_irqsave(&task_group_lock, flags);
7170 list_del_rcu(&tg->list);
7171 list_del_rcu(&tg->siblings);
7172 spin_unlock_irqrestore(&task_group_lock, flags);
7173
7174 /* wait for possible concurrent references to cfs_rqs complete */
7175 call_rcu(&tg->rcu, free_sched_group_rcu);
7176}
7177
7178/* change task's runqueue when it moves between groups.
7179 * The caller of this function should have put the task in its new group
7180 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7181 * reflect its new group.
7182 */
7183void sched_move_task(struct task_struct *tsk)
7184{
7185 int on_rq, running;
7186 unsigned long flags;
7187 struct rq *rq;
7188
7189 rq = task_rq_lock(tsk, &flags);
7190
7191 running = task_current(rq, tsk);
7192 on_rq = tsk->on_rq;
7193
7194 if (on_rq)
7195 dequeue_task(rq, tsk, 0);
7196 if (unlikely(running))
7197 tsk->sched_class->put_prev_task(rq, tsk);
7198
7199#ifdef CONFIG_FAIR_GROUP_SCHED
7200 if (tsk->sched_class->task_move_group)
7201 tsk->sched_class->task_move_group(tsk, on_rq);
7202 else
7203#endif
7204 set_task_rq(tsk, task_cpu(tsk));
7205
7206 if (unlikely(running))
7207 tsk->sched_class->set_curr_task(rq);
7208 if (on_rq)
7209 enqueue_task(rq, tsk, 0);
7210
7211 task_rq_unlock(rq, tsk, &flags);
7212}
7213#endif /* CONFIG_CGROUP_SCHED */
7214
7215#ifdef CONFIG_FAIR_GROUP_SCHED
7216#endif
7217
7218#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7219static unsigned long to_ratio(u64 period, u64 runtime)
7220{
7221 if (runtime == RUNTIME_INF)
7222 return 1ULL << 20;
7223
7224 return div64_u64(runtime << 20, period);
7225}
7226#endif
7227
7228#ifdef CONFIG_RT_GROUP_SCHED
7229/*
7230 * Ensure that the real time constraints are schedulable.
7231 */
7232static DEFINE_MUTEX(rt_constraints_mutex);
7233
7234/* Must be called with tasklist_lock held */
7235static inline int tg_has_rt_tasks(struct task_group *tg)
7236{
7237 struct task_struct *g, *p;
7238
7239 do_each_thread(g, p) {
7240 if (rt_task(p) && task_rq(p)->rt.tg == tg)
7241 return 1;
7242 } while_each_thread(g, p);
7243
7244 return 0;
7245}
7246
7247struct rt_schedulable_data {
7248 struct task_group *tg;
7249 u64 rt_period;
7250 u64 rt_runtime;
7251};
7252
7253static int tg_rt_schedulable(struct task_group *tg, void *data)
7254{
7255 struct rt_schedulable_data *d = data;
7256 struct task_group *child;
7257 unsigned long total, sum = 0;
7258 u64 period, runtime;
7259
7260 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7261 runtime = tg->rt_bandwidth.rt_runtime;
7262
7263 if (tg == d->tg) {
7264 period = d->rt_period;
7265 runtime = d->rt_runtime;
7266 }
7267
7268 /*
7269 * Cannot have more runtime than the period.
7270 */
7271 if (runtime > period && runtime != RUNTIME_INF)
7272 return -EINVAL;
7273
7274 /*
7275 * Ensure we don't starve existing RT tasks.
7276 */
7277 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
7278 return -EBUSY;
7279
7280 total = to_ratio(period, runtime);
7281
7282 /*
7283 * Nobody can have more than the global setting allows.
7284 */
7285 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
7286 return -EINVAL;
7287
7288 /*
7289 * The sum of our children's runtime should not exceed our own.
7290 */
7291 list_for_each_entry_rcu(child, &tg->children, siblings) {
7292 period = ktime_to_ns(child->rt_bandwidth.rt_period);
7293 runtime = child->rt_bandwidth.rt_runtime;
7294
7295 if (child == d->tg) {
7296 period = d->rt_period;
7297 runtime = d->rt_runtime;
7298 }
7299
7300 sum += to_ratio(period, runtime);
7301 }
7302
7303 if (sum > total)
7304 return -EINVAL;
7305
7306 return 0;
7307}
7308
7309static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7310{
7311 int ret;
7312
7313 struct rt_schedulable_data data = {
7314 .tg = tg,
7315 .rt_period = period,
7316 .rt_runtime = runtime,
7317 };
7318
7319 rcu_read_lock();
7320 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
7321 rcu_read_unlock();
7322
7323 return ret;
7324}
7325
7326static int tg_set_rt_bandwidth(struct task_group *tg,
7327 u64 rt_period, u64 rt_runtime)
7328{
7329 int i, err = 0;
7330
7331 mutex_lock(&rt_constraints_mutex);
7332 read_lock(&tasklist_lock);
7333 err = __rt_schedulable(tg, rt_period, rt_runtime);
7334 if (err)
7335 goto unlock;
7336
7337 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7338 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
7339 tg->rt_bandwidth.rt_runtime = rt_runtime;
7340
7341 for_each_possible_cpu(i) {
7342 struct rt_rq *rt_rq = tg->rt_rq[i];
7343
7344 raw_spin_lock(&rt_rq->rt_runtime_lock);
7345 rt_rq->rt_runtime = rt_runtime;
7346 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7347 }
7348 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7349unlock:
7350 read_unlock(&tasklist_lock);
7351 mutex_unlock(&rt_constraints_mutex);
7352
7353 return err;
7354}
7355
7356int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
7357{
7358 u64 rt_runtime, rt_period;
7359
7360 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7361 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
7362 if (rt_runtime_us < 0)
7363 rt_runtime = RUNTIME_INF;
7364
7365 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7366}
7367
7368long sched_group_rt_runtime(struct task_group *tg)
7369{
7370 u64 rt_runtime_us;
7371
7372 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
7373 return -1;
7374
7375 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
7376 do_div(rt_runtime_us, NSEC_PER_USEC);
7377 return rt_runtime_us;
7378}
7379
7380int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
7381{
7382 u64 rt_runtime, rt_period;
7383
7384 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
7385 rt_runtime = tg->rt_bandwidth.rt_runtime;
7386
7387 if (rt_period == 0)
7388 return -EINVAL;
7389
7390 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7391}
7392
7393long sched_group_rt_period(struct task_group *tg)
7394{
7395 u64 rt_period_us;
7396
7397 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7398 do_div(rt_period_us, NSEC_PER_USEC);
7399 return rt_period_us;
7400}
7401
7402static int sched_rt_global_constraints(void)
7403{
7404 u64 runtime, period;
7405 int ret = 0;
7406
7407 if (sysctl_sched_rt_period <= 0)
7408 return -EINVAL;
7409
7410 runtime = global_rt_runtime();
7411 period = global_rt_period();
7412
7413 /*
7414 * Sanity check on the sysctl variables.
7415 */
7416 if (runtime > period && runtime != RUNTIME_INF)
7417 return -EINVAL;
7418
7419 mutex_lock(&rt_constraints_mutex);
7420 read_lock(&tasklist_lock);
7421 ret = __rt_schedulable(NULL, 0, 0);
7422 read_unlock(&tasklist_lock);
7423 mutex_unlock(&rt_constraints_mutex);
7424
7425 return ret;
7426}
7427
7428int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
7429{
7430 /* Don't accept realtime tasks when there is no way for them to run */
7431 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7432 return 0;
7433
7434 return 1;
7435}
7436
7437#else /* !CONFIG_RT_GROUP_SCHED */
7438static int sched_rt_global_constraints(void)
7439{
7440 unsigned long flags;
7441 int i;
7442
7443 if (sysctl_sched_rt_period <= 0)
7444 return -EINVAL;
7445
7446 /*
7447 * There's always some RT tasks in the root group
7448 * -- migration, kstopmachine etc..
7449 */
7450 if (sysctl_sched_rt_runtime == 0)
7451 return -EBUSY;
7452
7453 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
7454 for_each_possible_cpu(i) {
7455 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7456
7457 raw_spin_lock(&rt_rq->rt_runtime_lock);
7458 rt_rq->rt_runtime = global_rt_runtime();
7459 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7460 }
7461 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
7462
7463 return 0;
7464}
7465#endif /* CONFIG_RT_GROUP_SCHED */
7466
7467int sched_rt_handler(struct ctl_table *table, int write,
7468 void __user *buffer, size_t *lenp,
7469 loff_t *ppos)
7470{
7471 int ret;
7472 int old_period, old_runtime;
7473 static DEFINE_MUTEX(mutex);
7474
7475 mutex_lock(&mutex);
7476 old_period = sysctl_sched_rt_period;
7477 old_runtime = sysctl_sched_rt_runtime;
7478
7479 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7480
7481 if (!ret && write) {
7482 ret = sched_rt_global_constraints();
7483 if (ret) {
7484 sysctl_sched_rt_period = old_period;
7485 sysctl_sched_rt_runtime = old_runtime;
7486 } else {
7487 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7488 def_rt_bandwidth.rt_period =
7489 ns_to_ktime(global_rt_period());
7490 }
7491 }
7492 mutex_unlock(&mutex);
7493
7494 return ret;
7495}
7496
7497#ifdef CONFIG_CGROUP_SCHED
7498
7499/* return corresponding task_group object of a cgroup */
7500static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
7501{
7502 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
7503 struct task_group, css);
7504}
7505
7506static struct cgroup_subsys_state *
7507cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
7508{
7509 struct task_group *tg, *parent;
7510
7511 if (!cgrp->parent) {
7512 /* This is early initialization for the top cgroup */
7513 return &root_task_group.css;
7514 }
7515
7516 parent = cgroup_tg(cgrp->parent);
7517 tg = sched_create_group(parent);
7518 if (IS_ERR(tg))
7519 return ERR_PTR(-ENOMEM);
7520
7521 return &tg->css;
7522}
7523
7524static void
7525cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
7526{
7527 struct task_group *tg = cgroup_tg(cgrp);
7528
7529 sched_destroy_group(tg);
7530}
7531
7532static int
7533cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
7534{
7535#ifdef CONFIG_RT_GROUP_SCHED
7536 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
7537 return -EINVAL;
7538#else
7539 /* We don't support RT-tasks being in separate groups */
7540 if (tsk->sched_class != &fair_sched_class)
7541 return -EINVAL;
7542#endif
7543 return 0;
7544}
7545
7546static void
7547cpu_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
7548{
7549 sched_move_task(tsk);
7550}
7551
7552static void
7553cpu_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
7554 struct cgroup *old_cgrp, struct task_struct *task)
7555{
7556 /*
7557 * cgroup_exit() is called in the copy_process() failure path.
7558 * Ignore this case since the task hasn't ran yet, this avoids
7559 * trying to poke a half freed task state from generic code.
7560 */
7561 if (!(task->flags & PF_EXITING))
7562 return;
7563
7564 sched_move_task(task);
7565}
7566
7567#ifdef CONFIG_FAIR_GROUP_SCHED
7568static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7569 u64 shareval)
7570{
7571 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval));
7572}
7573
7574static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
7575{
7576 struct task_group *tg = cgroup_tg(cgrp);
7577
7578 return (u64) scale_load_down(tg->shares);
7579}
7580
7581#ifdef CONFIG_CFS_BANDWIDTH
7582static DEFINE_MUTEX(cfs_constraints_mutex);
7583
7584const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
7585const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
7586
7587static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
7588
7589static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
7590{
7591 int i, ret = 0, runtime_enabled, runtime_was_enabled;
7592 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7593
7594 if (tg == &root_task_group)
7595 return -EINVAL;
7596
7597 /*
7598 * Ensure we have at some amount of bandwidth every period. This is
7599 * to prevent reaching a state of large arrears when throttled via
7600 * entity_tick() resulting in prolonged exit starvation.
7601 */
7602 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
7603 return -EINVAL;
7604
7605 /*
7606 * Likewise, bound things on the otherside by preventing insane quota
7607 * periods. This also allows us to normalize in computing quota
7608 * feasibility.
7609 */
7610 if (period > max_cfs_quota_period)
7611 return -EINVAL;
7612
7613 mutex_lock(&cfs_constraints_mutex);
7614 ret = __cfs_schedulable(tg, period, quota);
7615 if (ret)
7616 goto out_unlock;
7617
7618 runtime_enabled = quota != RUNTIME_INF;
7619 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
7620 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
7621 raw_spin_lock_irq(&cfs_b->lock);
7622 cfs_b->period = ns_to_ktime(period);
7623 cfs_b->quota = quota;
7624
7625 __refill_cfs_bandwidth_runtime(cfs_b);
7626 /* restart the period timer (if active) to handle new period expiry */
7627 if (runtime_enabled && cfs_b->timer_active) {
7628 /* force a reprogram */
7629 cfs_b->timer_active = 0;
7630 __start_cfs_bandwidth(cfs_b);
7631 }
7632 raw_spin_unlock_irq(&cfs_b->lock);
7633
7634 for_each_possible_cpu(i) {
7635 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
7636 struct rq *rq = cfs_rq->rq;
7637
7638 raw_spin_lock_irq(&rq->lock);
7639 cfs_rq->runtime_enabled = runtime_enabled;
7640 cfs_rq->runtime_remaining = 0;
7641
7642 if (cfs_rq->throttled)
7643 unthrottle_cfs_rq(cfs_rq);
7644 raw_spin_unlock_irq(&rq->lock);
7645 }
7646out_unlock:
7647 mutex_unlock(&cfs_constraints_mutex);
7648
7649 return ret;
7650}
7651
7652int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
7653{
7654 u64 quota, period;
7655
7656 period = ktime_to_ns(tg->cfs_bandwidth.period);
7657 if (cfs_quota_us < 0)
7658 quota = RUNTIME_INF;
7659 else
7660 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
7661
7662 return tg_set_cfs_bandwidth(tg, period, quota);
7663}
7664
7665long tg_get_cfs_quota(struct task_group *tg)
7666{
7667 u64 quota_us;
7668
7669 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
7670 return -1;
7671
7672 quota_us = tg->cfs_bandwidth.quota;
7673 do_div(quota_us, NSEC_PER_USEC);
7674
7675 return quota_us;
7676}
7677
7678int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
7679{
7680 u64 quota, period;
7681
7682 period = (u64)cfs_period_us * NSEC_PER_USEC;
7683 quota = tg->cfs_bandwidth.quota;
7684
7685 if (period <= 0)
7686 return -EINVAL;
7687
7688 return tg_set_cfs_bandwidth(tg, period, quota);
7689}
7690
7691long tg_get_cfs_period(struct task_group *tg)
7692{
7693 u64 cfs_period_us;
7694
7695 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
7696 do_div(cfs_period_us, NSEC_PER_USEC);
7697
7698 return cfs_period_us;
7699}
7700
7701static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft)
7702{
7703 return tg_get_cfs_quota(cgroup_tg(cgrp));
7704}
7705
7706static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype,
7707 s64 cfs_quota_us)
7708{
7709 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us);
7710}
7711
7712static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft)
7713{
7714 return tg_get_cfs_period(cgroup_tg(cgrp));
7715}
7716
7717static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7718 u64 cfs_period_us)
7719{
7720 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us);
7721}
7722
7723struct cfs_schedulable_data {
7724 struct task_group *tg;
7725 u64 period, quota;
7726};
7727
7728/*
7729 * normalize group quota/period to be quota/max_period
7730 * note: units are usecs
7731 */
7732static u64 normalize_cfs_quota(struct task_group *tg,
7733 struct cfs_schedulable_data *d)
7734{
7735 u64 quota, period;
7736
7737 if (tg == d->tg) {
7738 period = d->period;
7739 quota = d->quota;
7740 } else {
7741 period = tg_get_cfs_period(tg);
7742 quota = tg_get_cfs_quota(tg);
7743 }
7744
7745 /* note: these should typically be equivalent */
7746 if (quota == RUNTIME_INF || quota == -1)
7747 return RUNTIME_INF;
7748
7749 return to_ratio(period, quota);
7750}
7751
7752static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
7753{
7754 struct cfs_schedulable_data *d = data;
7755 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7756 s64 quota = 0, parent_quota = -1;
7757
7758 if (!tg->parent) {
7759 quota = RUNTIME_INF;
7760 } else {
7761 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
7762
7763 quota = normalize_cfs_quota(tg, d);
7764 parent_quota = parent_b->hierarchal_quota;
7765
7766 /*
7767 * ensure max(child_quota) <= parent_quota, inherit when no
7768 * limit is set
7769 */
7770 if (quota == RUNTIME_INF)
7771 quota = parent_quota;
7772 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
7773 return -EINVAL;
7774 }
7775 cfs_b->hierarchal_quota = quota;
7776
7777 return 0;
7778}
7779
7780static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
7781{
7782 int ret;
7783 struct cfs_schedulable_data data = {
7784 .tg = tg,
7785 .period = period,
7786 .quota = quota,
7787 };
7788
7789 if (quota != RUNTIME_INF) {
7790 do_div(data.period, NSEC_PER_USEC);
7791 do_div(data.quota, NSEC_PER_USEC);
7792 }
7793
7794 rcu_read_lock();
7795 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
7796 rcu_read_unlock();
7797
7798 return ret;
7799}
7800
7801static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft,
7802 struct cgroup_map_cb *cb)
7803{
7804 struct task_group *tg = cgroup_tg(cgrp);
7805 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7806
7807 cb->fill(cb, "nr_periods", cfs_b->nr_periods);
7808 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
7809 cb->fill(cb, "throttled_time", cfs_b->throttled_time);
7810
7811 return 0;
7812}
7813#endif /* CONFIG_CFS_BANDWIDTH */
7814#endif /* CONFIG_FAIR_GROUP_SCHED */
7815
7816#ifdef CONFIG_RT_GROUP_SCHED
7817static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
7818 s64 val)
7819{
7820 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
7821}
7822
7823static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
7824{
7825 return sched_group_rt_runtime(cgroup_tg(cgrp));
7826}
7827
7828static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
7829 u64 rt_period_us)
7830{
7831 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
7832}
7833
7834static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
7835{
7836 return sched_group_rt_period(cgroup_tg(cgrp));
7837}
7838#endif /* CONFIG_RT_GROUP_SCHED */
7839
7840static struct cftype cpu_files[] = {
7841#ifdef CONFIG_FAIR_GROUP_SCHED
7842 {
7843 .name = "shares",
7844 .read_u64 = cpu_shares_read_u64,
7845 .write_u64 = cpu_shares_write_u64,
7846 },
7847#endif
7848#ifdef CONFIG_CFS_BANDWIDTH
7849 {
7850 .name = "cfs_quota_us",
7851 .read_s64 = cpu_cfs_quota_read_s64,
7852 .write_s64 = cpu_cfs_quota_write_s64,
7853 },
7854 {
7855 .name = "cfs_period_us",
7856 .read_u64 = cpu_cfs_period_read_u64,
7857 .write_u64 = cpu_cfs_period_write_u64,
7858 },
7859 {
7860 .name = "stat",
7861 .read_map = cpu_stats_show,
7862 },
7863#endif
7864#ifdef CONFIG_RT_GROUP_SCHED
7865 {
7866 .name = "rt_runtime_us",
7867 .read_s64 = cpu_rt_runtime_read,
7868 .write_s64 = cpu_rt_runtime_write,
7869 },
7870 {
7871 .name = "rt_period_us",
7872 .read_u64 = cpu_rt_period_read_uint,
7873 .write_u64 = cpu_rt_period_write_uint,
7874 },
7875#endif
7876};
7877
7878static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
7879{
7880 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
7881}
7882
7883struct cgroup_subsys cpu_cgroup_subsys = {
7884 .name = "cpu",
7885 .create = cpu_cgroup_create,
7886 .destroy = cpu_cgroup_destroy,
7887 .can_attach_task = cpu_cgroup_can_attach_task,
7888 .attach_task = cpu_cgroup_attach_task,
7889 .exit = cpu_cgroup_exit,
7890 .populate = cpu_cgroup_populate,
7891 .subsys_id = cpu_cgroup_subsys_id,
7892 .early_init = 1,
7893};
7894
7895#endif /* CONFIG_CGROUP_SCHED */
7896
7897#ifdef CONFIG_CGROUP_CPUACCT
7898
7899/*
7900 * CPU accounting code for task groups.
7901 *
7902 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
7903 * (balbir@in.ibm.com).
7904 */
7905
7906/* create a new cpu accounting group */
7907static struct cgroup_subsys_state *cpuacct_create(
7908 struct cgroup_subsys *ss, struct cgroup *cgrp)
7909{
7910 struct cpuacct *ca;
7911
7912 if (!cgrp->parent)
7913 return &root_cpuacct.css;
7914
7915 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
7916 if (!ca)
7917 goto out;
7918
7919 ca->cpuusage = alloc_percpu(u64);
7920 if (!ca->cpuusage)
7921 goto out_free_ca;
7922
7923 ca->cpustat = alloc_percpu(struct kernel_cpustat);
7924 if (!ca->cpustat)
7925 goto out_free_cpuusage;
7926
7927 return &ca->css;
7928
7929out_free_cpuusage:
7930 free_percpu(ca->cpuusage);
7931out_free_ca:
7932 kfree(ca);
7933out:
7934 return ERR_PTR(-ENOMEM);
7935}
7936
7937/* destroy an existing cpu accounting group */
7938static void
7939cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
7940{
7941 struct cpuacct *ca = cgroup_ca(cgrp);
7942
7943 free_percpu(ca->cpustat);
7944 free_percpu(ca->cpuusage);
7945 kfree(ca);
7946}
7947
7948static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
7949{
7950 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
7951 u64 data;
7952
7953#ifndef CONFIG_64BIT
7954 /*
7955 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
7956 */
7957 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
7958 data = *cpuusage;
7959 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
7960#else
7961 data = *cpuusage;
7962#endif
7963
7964 return data;
7965}
7966
7967static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
7968{
7969 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
7970
7971#ifndef CONFIG_64BIT
7972 /*
7973 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
7974 */
7975 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
7976 *cpuusage = val;
7977 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
7978#else
7979 *cpuusage = val;
7980#endif
7981}
7982
7983/* return total cpu usage (in nanoseconds) of a group */
7984static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
7985{
7986 struct cpuacct *ca = cgroup_ca(cgrp);
7987 u64 totalcpuusage = 0;
7988 int i;
7989
7990 for_each_present_cpu(i)
7991 totalcpuusage += cpuacct_cpuusage_read(ca, i);
7992
7993 return totalcpuusage;
7994}
7995
7996static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
7997 u64 reset)
7998{
7999 struct cpuacct *ca = cgroup_ca(cgrp);
8000 int err = 0;
8001 int i;
8002
8003 if (reset) {
8004 err = -EINVAL;
8005 goto out;
8006 }
8007
8008 for_each_present_cpu(i)
8009 cpuacct_cpuusage_write(ca, i, 0);
8010
8011out:
8012 return err;
8013}
8014
8015static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
8016 struct seq_file *m)
8017{
8018 struct cpuacct *ca = cgroup_ca(cgroup);
8019 u64 percpu;
8020 int i;
8021
8022 for_each_present_cpu(i) {
8023 percpu = cpuacct_cpuusage_read(ca, i);
8024 seq_printf(m, "%llu ", (unsigned long long) percpu);
8025 }
8026 seq_printf(m, "\n");
8027 return 0;
8028}
8029
8030static const char *cpuacct_stat_desc[] = {
8031 [CPUACCT_STAT_USER] = "user",
8032 [CPUACCT_STAT_SYSTEM] = "system",
8033};
8034
8035static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8036 struct cgroup_map_cb *cb)
8037{
8038 struct cpuacct *ca = cgroup_ca(cgrp);
8039 int cpu;
8040 s64 val = 0;
8041
8042 for_each_online_cpu(cpu) {
8043 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8044 val += kcpustat->cpustat[CPUTIME_USER];
8045 val += kcpustat->cpustat[CPUTIME_NICE];
8046 }
8047 val = cputime64_to_clock_t(val);
8048 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
8049
8050 val = 0;
8051 for_each_online_cpu(cpu) {
8052 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8053 val += kcpustat->cpustat[CPUTIME_SYSTEM];
8054 val += kcpustat->cpustat[CPUTIME_IRQ];
8055 val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
8056 }
8057
8058 val = cputime64_to_clock_t(val);
8059 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
8060
8061 return 0;
8062}
8063
8064static struct cftype files[] = {
8065 {
8066 .name = "usage",
8067 .read_u64 = cpuusage_read,
8068 .write_u64 = cpuusage_write,
8069 },
8070 {
8071 .name = "usage_percpu",
8072 .read_seq_string = cpuacct_percpu_seq_read,
8073 },
8074 {
8075 .name = "stat",
8076 .read_map = cpuacct_stats_show,
8077 },
8078};
8079
8080static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
8081{
8082 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
8083}
8084
8085/*
8086 * charge this task's execution time to its accounting group.
8087 *
8088 * called with rq->lock held.
8089 */
8090void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8091{
8092 struct cpuacct *ca;
8093 int cpu;
8094
8095 if (unlikely(!cpuacct_subsys.active))
8096 return;
8097
8098 cpu = task_cpu(tsk);
8099
8100 rcu_read_lock();
8101
8102 ca = task_ca(tsk);
8103
8104 for (; ca; ca = parent_ca(ca)) {
8105 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8106 *cpuusage += cputime;
8107 }
8108
8109 rcu_read_unlock();
8110}
8111
8112struct cgroup_subsys cpuacct_subsys = {
8113 .name = "cpuacct",
8114 .create = cpuacct_create,
8115 .destroy = cpuacct_destroy,
8116 .populate = cpuacct_populate,
8117 .subsys_id = cpuacct_subsys_id,
8118};
8119#endif /* CONFIG_CGROUP_CPUACCT */
diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c
new file mode 100644
index 000000000000..b0d798eaf130
--- /dev/null
+++ b/kernel/sched/cpupri.c
@@ -0,0 +1,241 @@
1/*
2 * kernel/sched/cpupri.c
3 *
4 * CPU priority management
5 *
6 * Copyright (C) 2007-2008 Novell
7 *
8 * Author: Gregory Haskins <ghaskins@novell.com>
9 *
10 * This code tracks the priority of each CPU so that global migration
11 * decisions are easy to calculate. Each CPU can be in a state as follows:
12 *
13 * (INVALID), IDLE, NORMAL, RT1, ... RT99
14 *
15 * going from the lowest priority to the highest. CPUs in the INVALID state
16 * are not eligible for routing. The system maintains this state with
17 * a 2 dimensional bitmap (the first for priority class, the second for cpus
18 * in that class). Therefore a typical application without affinity
19 * restrictions can find a suitable CPU with O(1) complexity (e.g. two bit
20 * searches). For tasks with affinity restrictions, the algorithm has a
21 * worst case complexity of O(min(102, nr_domcpus)), though the scenario that
22 * yields the worst case search is fairly contrived.
23 *
24 * This program is free software; you can redistribute it and/or
25 * modify it under the terms of the GNU General Public License
26 * as published by the Free Software Foundation; version 2
27 * of the License.
28 */
29
30#include <linux/gfp.h>
31#include "cpupri.h"
32
33/* Convert between a 140 based task->prio, and our 102 based cpupri */
34static int convert_prio(int prio)
35{
36 int cpupri;
37
38 if (prio == CPUPRI_INVALID)
39 cpupri = CPUPRI_INVALID;
40 else if (prio == MAX_PRIO)
41 cpupri = CPUPRI_IDLE;
42 else if (prio >= MAX_RT_PRIO)
43 cpupri = CPUPRI_NORMAL;
44 else
45 cpupri = MAX_RT_PRIO - prio + 1;
46
47 return cpupri;
48}
49
50/**
51 * cpupri_find - find the best (lowest-pri) CPU in the system
52 * @cp: The cpupri context
53 * @p: The task
54 * @lowest_mask: A mask to fill in with selected CPUs (or NULL)
55 *
56 * Note: This function returns the recommended CPUs as calculated during the
57 * current invocation. By the time the call returns, the CPUs may have in
58 * fact changed priorities any number of times. While not ideal, it is not
59 * an issue of correctness since the normal rebalancer logic will correct
60 * any discrepancies created by racing against the uncertainty of the current
61 * priority configuration.
62 *
63 * Returns: (int)bool - CPUs were found
64 */
65int cpupri_find(struct cpupri *cp, struct task_struct *p,
66 struct cpumask *lowest_mask)
67{
68 int idx = 0;
69 int task_pri = convert_prio(p->prio);
70
71 if (task_pri >= MAX_RT_PRIO)
72 return 0;
73
74 for (idx = 0; idx < task_pri; idx++) {
75 struct cpupri_vec *vec = &cp->pri_to_cpu[idx];
76 int skip = 0;
77
78 if (!atomic_read(&(vec)->count))
79 skip = 1;
80 /*
81 * When looking at the vector, we need to read the counter,
82 * do a memory barrier, then read the mask.
83 *
84 * Note: This is still all racey, but we can deal with it.
85 * Ideally, we only want to look at masks that are set.
86 *
87 * If a mask is not set, then the only thing wrong is that we
88 * did a little more work than necessary.
89 *
90 * If we read a zero count but the mask is set, because of the
91 * memory barriers, that can only happen when the highest prio
92 * task for a run queue has left the run queue, in which case,
93 * it will be followed by a pull. If the task we are processing
94 * fails to find a proper place to go, that pull request will
95 * pull this task if the run queue is running at a lower
96 * priority.
97 */
98 smp_rmb();
99
100 /* Need to do the rmb for every iteration */
101 if (skip)
102 continue;
103
104 if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
105 continue;
106
107 if (lowest_mask) {
108 cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
109
110 /*
111 * We have to ensure that we have at least one bit
112 * still set in the array, since the map could have
113 * been concurrently emptied between the first and
114 * second reads of vec->mask. If we hit this
115 * condition, simply act as though we never hit this
116 * priority level and continue on.
117 */
118 if (cpumask_any(lowest_mask) >= nr_cpu_ids)
119 continue;
120 }
121
122 return 1;
123 }
124
125 return 0;
126}
127
128/**
129 * cpupri_set - update the cpu priority setting
130 * @cp: The cpupri context
131 * @cpu: The target cpu
132 * @pri: The priority (INVALID-RT99) to assign to this CPU
133 *
134 * Note: Assumes cpu_rq(cpu)->lock is locked
135 *
136 * Returns: (void)
137 */
138void cpupri_set(struct cpupri *cp, int cpu, int newpri)
139{
140 int *currpri = &cp->cpu_to_pri[cpu];
141 int oldpri = *currpri;
142 int do_mb = 0;
143
144 newpri = convert_prio(newpri);
145
146 BUG_ON(newpri >= CPUPRI_NR_PRIORITIES);
147
148 if (newpri == oldpri)
149 return;
150
151 /*
152 * If the cpu was currently mapped to a different value, we
153 * need to map it to the new value then remove the old value.
154 * Note, we must add the new value first, otherwise we risk the
155 * cpu being missed by the priority loop in cpupri_find.
156 */
157 if (likely(newpri != CPUPRI_INVALID)) {
158 struct cpupri_vec *vec = &cp->pri_to_cpu[newpri];
159
160 cpumask_set_cpu(cpu, vec->mask);
161 /*
162 * When adding a new vector, we update the mask first,
163 * do a write memory barrier, and then update the count, to
164 * make sure the vector is visible when count is set.
165 */
166 smp_mb__before_atomic_inc();
167 atomic_inc(&(vec)->count);
168 do_mb = 1;
169 }
170 if (likely(oldpri != CPUPRI_INVALID)) {
171 struct cpupri_vec *vec = &cp->pri_to_cpu[oldpri];
172
173 /*
174 * Because the order of modification of the vec->count
175 * is important, we must make sure that the update
176 * of the new prio is seen before we decrement the
177 * old prio. This makes sure that the loop sees
178 * one or the other when we raise the priority of
179 * the run queue. We don't care about when we lower the
180 * priority, as that will trigger an rt pull anyway.
181 *
182 * We only need to do a memory barrier if we updated
183 * the new priority vec.
184 */
185 if (do_mb)
186 smp_mb__after_atomic_inc();
187
188 /*
189 * When removing from the vector, we decrement the counter first
190 * do a memory barrier and then clear the mask.
191 */
192 atomic_dec(&(vec)->count);
193 smp_mb__after_atomic_inc();
194 cpumask_clear_cpu(cpu, vec->mask);
195 }
196
197 *currpri = newpri;
198}
199
200/**
201 * cpupri_init - initialize the cpupri structure
202 * @cp: The cpupri context
203 * @bootmem: true if allocations need to use bootmem
204 *
205 * Returns: -ENOMEM if memory fails.
206 */
207int cpupri_init(struct cpupri *cp)
208{
209 int i;
210
211 memset(cp, 0, sizeof(*cp));
212
213 for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) {
214 struct cpupri_vec *vec = &cp->pri_to_cpu[i];
215
216 atomic_set(&vec->count, 0);
217 if (!zalloc_cpumask_var(&vec->mask, GFP_KERNEL))
218 goto cleanup;
219 }
220
221 for_each_possible_cpu(i)
222 cp->cpu_to_pri[i] = CPUPRI_INVALID;
223 return 0;
224
225cleanup:
226 for (i--; i >= 0; i--)
227 free_cpumask_var(cp->pri_to_cpu[i].mask);
228 return -ENOMEM;
229}
230
231/**
232 * cpupri_cleanup - clean up the cpupri structure
233 * @cp: The cpupri context
234 */
235void cpupri_cleanup(struct cpupri *cp)
236{
237 int i;
238
239 for (i = 0; i < CPUPRI_NR_PRIORITIES; i++)
240 free_cpumask_var(cp->pri_to_cpu[i].mask);
241}
diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h
new file mode 100644
index 000000000000..f6d756173491
--- /dev/null
+++ b/kernel/sched/cpupri.h
@@ -0,0 +1,34 @@
1#ifndef _LINUX_CPUPRI_H
2#define _LINUX_CPUPRI_H
3
4#include <linux/sched.h>
5
6#define CPUPRI_NR_PRIORITIES (MAX_RT_PRIO + 2)
7
8#define CPUPRI_INVALID -1
9#define CPUPRI_IDLE 0
10#define CPUPRI_NORMAL 1
11/* values 2-101 are RT priorities 0-99 */
12
13struct cpupri_vec {
14 atomic_t count;
15 cpumask_var_t mask;
16};
17
18struct cpupri {
19 struct cpupri_vec pri_to_cpu[CPUPRI_NR_PRIORITIES];
20 int cpu_to_pri[NR_CPUS];
21};
22
23#ifdef CONFIG_SMP
24int cpupri_find(struct cpupri *cp,
25 struct task_struct *p, struct cpumask *lowest_mask);
26void cpupri_set(struct cpupri *cp, int cpu, int pri);
27int cpupri_init(struct cpupri *cp);
28void cpupri_cleanup(struct cpupri *cp);
29#else
30#define cpupri_set(cp, cpu, pri) do { } while (0)
31#define cpupri_init() do { } while (0)
32#endif
33
34#endif /* _LINUX_CPUPRI_H */
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
new file mode 100644
index 000000000000..2a075e10004b
--- /dev/null
+++ b/kernel/sched/debug.c
@@ -0,0 +1,510 @@
1/*
2 * kernel/sched/debug.c
3 *
4 * Print the CFS rbtree
5 *
6 * Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/proc_fs.h>
14#include <linux/sched.h>
15#include <linux/seq_file.h>
16#include <linux/kallsyms.h>
17#include <linux/utsname.h>
18
19#include "sched.h"
20
21static DEFINE_SPINLOCK(sched_debug_lock);
22
23/*
24 * This allows printing both to /proc/sched_debug and
25 * to the console
26 */
27#define SEQ_printf(m, x...) \
28 do { \
29 if (m) \
30 seq_printf(m, x); \
31 else \
32 printk(x); \
33 } while (0)
34
35/*
36 * Ease the printing of nsec fields:
37 */
38static long long nsec_high(unsigned long long nsec)
39{
40 if ((long long)nsec < 0) {
41 nsec = -nsec;
42 do_div(nsec, 1000000);
43 return -nsec;
44 }
45 do_div(nsec, 1000000);
46
47 return nsec;
48}
49
50static unsigned long nsec_low(unsigned long long nsec)
51{
52 if ((long long)nsec < 0)
53 nsec = -nsec;
54
55 return do_div(nsec, 1000000);
56}
57
58#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
59
60#ifdef CONFIG_FAIR_GROUP_SCHED
61static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
62{
63 struct sched_entity *se = tg->se[cpu];
64 if (!se)
65 return;
66
67#define P(F) \
68 SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
69#define PN(F) \
70 SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
71
72 PN(se->exec_start);
73 PN(se->vruntime);
74 PN(se->sum_exec_runtime);
75#ifdef CONFIG_SCHEDSTATS
76 PN(se->statistics.wait_start);
77 PN(se->statistics.sleep_start);
78 PN(se->statistics.block_start);
79 PN(se->statistics.sleep_max);
80 PN(se->statistics.block_max);
81 PN(se->statistics.exec_max);
82 PN(se->statistics.slice_max);
83 PN(se->statistics.wait_max);
84 PN(se->statistics.wait_sum);
85 P(se->statistics.wait_count);
86#endif
87 P(se->load.weight);
88#undef PN
89#undef P
90}
91#endif
92
93#ifdef CONFIG_CGROUP_SCHED
94static char group_path[PATH_MAX];
95
96static char *task_group_path(struct task_group *tg)
97{
98 if (autogroup_path(tg, group_path, PATH_MAX))
99 return group_path;
100
101 /*
102 * May be NULL if the underlying cgroup isn't fully-created yet
103 */
104 if (!tg->css.cgroup) {
105 group_path[0] = '\0';
106 return group_path;
107 }
108 cgroup_path(tg->css.cgroup, group_path, PATH_MAX);
109 return group_path;
110}
111#endif
112
113static void
114print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
115{
116 if (rq->curr == p)
117 SEQ_printf(m, "R");
118 else
119 SEQ_printf(m, " ");
120
121 SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ",
122 p->comm, p->pid,
123 SPLIT_NS(p->se.vruntime),
124 (long long)(p->nvcsw + p->nivcsw),
125 p->prio);
126#ifdef CONFIG_SCHEDSTATS
127 SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
128 SPLIT_NS(p->se.vruntime),
129 SPLIT_NS(p->se.sum_exec_runtime),
130 SPLIT_NS(p->se.statistics.sum_sleep_runtime));
131#else
132 SEQ_printf(m, "%15Ld %15Ld %15Ld.%06ld %15Ld.%06ld %15Ld.%06ld",
133 0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
134#endif
135#ifdef CONFIG_CGROUP_SCHED
136 SEQ_printf(m, " %s", task_group_path(task_group(p)));
137#endif
138
139 SEQ_printf(m, "\n");
140}
141
142static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
143{
144 struct task_struct *g, *p;
145 unsigned long flags;
146
147 SEQ_printf(m,
148 "\nrunnable tasks:\n"
149 " task PID tree-key switches prio"
150 " exec-runtime sum-exec sum-sleep\n"
151 "------------------------------------------------------"
152 "----------------------------------------------------\n");
153
154 read_lock_irqsave(&tasklist_lock, flags);
155
156 do_each_thread(g, p) {
157 if (!p->on_rq || task_cpu(p) != rq_cpu)
158 continue;
159
160 print_task(m, rq, p);
161 } while_each_thread(g, p);
162
163 read_unlock_irqrestore(&tasklist_lock, flags);
164}
165
166void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
167{
168 s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
169 spread, rq0_min_vruntime, spread0;
170 struct rq *rq = cpu_rq(cpu);
171 struct sched_entity *last;
172 unsigned long flags;
173
174#ifdef CONFIG_FAIR_GROUP_SCHED
175 SEQ_printf(m, "\ncfs_rq[%d]:%s\n", cpu, task_group_path(cfs_rq->tg));
176#else
177 SEQ_printf(m, "\ncfs_rq[%d]:\n", cpu);
178#endif
179 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "exec_clock",
180 SPLIT_NS(cfs_rq->exec_clock));
181
182 raw_spin_lock_irqsave(&rq->lock, flags);
183 if (cfs_rq->rb_leftmost)
184 MIN_vruntime = (__pick_first_entity(cfs_rq))->vruntime;
185 last = __pick_last_entity(cfs_rq);
186 if (last)
187 max_vruntime = last->vruntime;
188 min_vruntime = cfs_rq->min_vruntime;
189 rq0_min_vruntime = cpu_rq(0)->cfs.min_vruntime;
190 raw_spin_unlock_irqrestore(&rq->lock, flags);
191 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "MIN_vruntime",
192 SPLIT_NS(MIN_vruntime));
193 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "min_vruntime",
194 SPLIT_NS(min_vruntime));
195 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "max_vruntime",
196 SPLIT_NS(max_vruntime));
197 spread = max_vruntime - MIN_vruntime;
198 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread",
199 SPLIT_NS(spread));
200 spread0 = min_vruntime - rq0_min_vruntime;
201 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread0",
202 SPLIT_NS(spread0));
203 SEQ_printf(m, " .%-30s: %d\n", "nr_spread_over",
204 cfs_rq->nr_spread_over);
205 SEQ_printf(m, " .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
206 SEQ_printf(m, " .%-30s: %ld\n", "load", cfs_rq->load.weight);
207#ifdef CONFIG_FAIR_GROUP_SCHED
208#ifdef CONFIG_SMP
209 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "load_avg",
210 SPLIT_NS(cfs_rq->load_avg));
211 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "load_period",
212 SPLIT_NS(cfs_rq->load_period));
213 SEQ_printf(m, " .%-30s: %ld\n", "load_contrib",
214 cfs_rq->load_contribution);
215 SEQ_printf(m, " .%-30s: %d\n", "load_tg",
216 atomic_read(&cfs_rq->tg->load_weight));
217#endif
218
219 print_cfs_group_stats(m, cpu, cfs_rq->tg);
220#endif
221}
222
223void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
224{
225#ifdef CONFIG_RT_GROUP_SCHED
226 SEQ_printf(m, "\nrt_rq[%d]:%s\n", cpu, task_group_path(rt_rq->tg));
227#else
228 SEQ_printf(m, "\nrt_rq[%d]:\n", cpu);
229#endif
230
231#define P(x) \
232 SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rt_rq->x))
233#define PN(x) \
234 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))
235
236 P(rt_nr_running);
237 P(rt_throttled);
238 PN(rt_time);
239 PN(rt_runtime);
240
241#undef PN
242#undef P
243}
244
245extern __read_mostly int sched_clock_running;
246
247static void print_cpu(struct seq_file *m, int cpu)
248{
249 struct rq *rq = cpu_rq(cpu);
250 unsigned long flags;
251
252#ifdef CONFIG_X86
253 {
254 unsigned int freq = cpu_khz ? : 1;
255
256 SEQ_printf(m, "\ncpu#%d, %u.%03u MHz\n",
257 cpu, freq / 1000, (freq % 1000));
258 }
259#else
260 SEQ_printf(m, "\ncpu#%d\n", cpu);
261#endif
262
263#define P(x) \
264 SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rq->x))
265#define PN(x) \
266 SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
267
268 P(nr_running);
269 SEQ_printf(m, " .%-30s: %lu\n", "load",
270 rq->load.weight);
271 P(nr_switches);
272 P(nr_load_updates);
273 P(nr_uninterruptible);
274 PN(next_balance);
275 P(curr->pid);
276 PN(clock);
277 P(cpu_load[0]);
278 P(cpu_load[1]);
279 P(cpu_load[2]);
280 P(cpu_load[3]);
281 P(cpu_load[4]);
282#undef P
283#undef PN
284
285#ifdef CONFIG_SCHEDSTATS
286#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
287#define P64(n) SEQ_printf(m, " .%-30s: %Ld\n", #n, rq->n);
288
289 P(yld_count);
290
291 P(sched_switch);
292 P(sched_count);
293 P(sched_goidle);
294#ifdef CONFIG_SMP
295 P64(avg_idle);
296#endif
297
298 P(ttwu_count);
299 P(ttwu_local);
300
301#undef P
302#undef P64
303#endif
304 spin_lock_irqsave(&sched_debug_lock, flags);
305 print_cfs_stats(m, cpu);
306 print_rt_stats(m, cpu);
307
308 rcu_read_lock();
309 print_rq(m, rq, cpu);
310 rcu_read_unlock();
311 spin_unlock_irqrestore(&sched_debug_lock, flags);
312}
313
314static const char *sched_tunable_scaling_names[] = {
315 "none",
316 "logaritmic",
317 "linear"
318};
319
320static int sched_debug_show(struct seq_file *m, void *v)
321{
322 u64 ktime, sched_clk, cpu_clk;
323 unsigned long flags;
324 int cpu;
325
326 local_irq_save(flags);
327 ktime = ktime_to_ns(ktime_get());
328 sched_clk = sched_clock();
329 cpu_clk = local_clock();
330 local_irq_restore(flags);
331
332 SEQ_printf(m, "Sched Debug Version: v0.10, %s %.*s\n",
333 init_utsname()->release,
334 (int)strcspn(init_utsname()->version, " "),
335 init_utsname()->version);
336
337#define P(x) \
338 SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x))
339#define PN(x) \
340 SEQ_printf(m, "%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
341 PN(ktime);
342 PN(sched_clk);
343 PN(cpu_clk);
344 P(jiffies);
345#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
346 P(sched_clock_stable);
347#endif
348#undef PN
349#undef P
350
351 SEQ_printf(m, "\n");
352 SEQ_printf(m, "sysctl_sched\n");
353
354#define P(x) \
355 SEQ_printf(m, " .%-40s: %Ld\n", #x, (long long)(x))
356#define PN(x) \
357 SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
358 PN(sysctl_sched_latency);
359 PN(sysctl_sched_min_granularity);
360 PN(sysctl_sched_wakeup_granularity);
361 P(sysctl_sched_child_runs_first);
362 P(sysctl_sched_features);
363#undef PN
364#undef P
365
366 SEQ_printf(m, " .%-40s: %d (%s)\n", "sysctl_sched_tunable_scaling",
367 sysctl_sched_tunable_scaling,
368 sched_tunable_scaling_names[sysctl_sched_tunable_scaling]);
369
370 for_each_online_cpu(cpu)
371 print_cpu(m, cpu);
372
373 SEQ_printf(m, "\n");
374
375 return 0;
376}
377
378void sysrq_sched_debug_show(void)
379{
380 sched_debug_show(NULL, NULL);
381}
382
383static int sched_debug_open(struct inode *inode, struct file *filp)
384{
385 return single_open(filp, sched_debug_show, NULL);
386}
387
388static const struct file_operations sched_debug_fops = {
389 .open = sched_debug_open,
390 .read = seq_read,
391 .llseek = seq_lseek,
392 .release = single_release,
393};
394
395static int __init init_sched_debug_procfs(void)
396{
397 struct proc_dir_entry *pe;
398
399 pe = proc_create("sched_debug", 0444, NULL, &sched_debug_fops);
400 if (!pe)
401 return -ENOMEM;
402 return 0;
403}
404
405__initcall(init_sched_debug_procfs);
406
407void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
408{
409 unsigned long nr_switches;
410
411 SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid,
412 get_nr_threads(p));
413 SEQ_printf(m,
414 "---------------------------------------------------------\n");
415#define __P(F) \
416 SEQ_printf(m, "%-35s:%21Ld\n", #F, (long long)F)
417#define P(F) \
418 SEQ_printf(m, "%-35s:%21Ld\n", #F, (long long)p->F)
419#define __PN(F) \
420 SEQ_printf(m, "%-35s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)F))
421#define PN(F) \
422 SEQ_printf(m, "%-35s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)p->F))
423
424 PN(se.exec_start);
425 PN(se.vruntime);
426 PN(se.sum_exec_runtime);
427
428 nr_switches = p->nvcsw + p->nivcsw;
429
430#ifdef CONFIG_SCHEDSTATS
431 PN(se.statistics.wait_start);
432 PN(se.statistics.sleep_start);
433 PN(se.statistics.block_start);
434 PN(se.statistics.sleep_max);
435 PN(se.statistics.block_max);
436 PN(se.statistics.exec_max);
437 PN(se.statistics.slice_max);
438 PN(se.statistics.wait_max);
439 PN(se.statistics.wait_sum);
440 P(se.statistics.wait_count);
441 PN(se.statistics.iowait_sum);
442 P(se.statistics.iowait_count);
443 P(se.nr_migrations);
444 P(se.statistics.nr_migrations_cold);
445 P(se.statistics.nr_failed_migrations_affine);
446 P(se.statistics.nr_failed_migrations_running);
447 P(se.statistics.nr_failed_migrations_hot);
448 P(se.statistics.nr_forced_migrations);
449 P(se.statistics.nr_wakeups);
450 P(se.statistics.nr_wakeups_sync);
451 P(se.statistics.nr_wakeups_migrate);
452 P(se.statistics.nr_wakeups_local);
453 P(se.statistics.nr_wakeups_remote);
454 P(se.statistics.nr_wakeups_affine);
455 P(se.statistics.nr_wakeups_affine_attempts);
456 P(se.statistics.nr_wakeups_passive);
457 P(se.statistics.nr_wakeups_idle);
458
459 {
460 u64 avg_atom, avg_per_cpu;
461
462 avg_atom = p->se.sum_exec_runtime;
463 if (nr_switches)
464 do_div(avg_atom, nr_switches);
465 else
466 avg_atom = -1LL;
467
468 avg_per_cpu = p->se.sum_exec_runtime;
469 if (p->se.nr_migrations) {
470 avg_per_cpu = div64_u64(avg_per_cpu,
471 p->se.nr_migrations);
472 } else {
473 avg_per_cpu = -1LL;
474 }
475
476 __PN(avg_atom);
477 __PN(avg_per_cpu);
478 }
479#endif
480 __P(nr_switches);
481 SEQ_printf(m, "%-35s:%21Ld\n",
482 "nr_voluntary_switches", (long long)p->nvcsw);
483 SEQ_printf(m, "%-35s:%21Ld\n",
484 "nr_involuntary_switches", (long long)p->nivcsw);
485
486 P(se.load.weight);
487 P(policy);
488 P(prio);
489#undef PN
490#undef __PN
491#undef P
492#undef __P
493
494 {
495 unsigned int this_cpu = raw_smp_processor_id();
496 u64 t0, t1;
497
498 t0 = cpu_clock(this_cpu);
499 t1 = cpu_clock(this_cpu);
500 SEQ_printf(m, "%-35s:%21Ld\n",
501 "clock-delta", (long long)(t1-t0));
502 }
503}
504
505void proc_sched_set_task(struct task_struct *p)
506{
507#ifdef CONFIG_SCHEDSTATS
508 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
509#endif
510}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
new file mode 100644
index 000000000000..a4d2b7abc3cd
--- /dev/null
+++ b/kernel/sched/fair.c
@@ -0,0 +1,5577 @@
1/*
2 * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH)
3 *
4 * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
5 *
6 * Interactivity improvements by Mike Galbraith
7 * (C) 2007 Mike Galbraith <efault@gmx.de>
8 *
9 * Various enhancements by Dmitry Adamushko.
10 * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com>
11 *
12 * Group scheduling enhancements by Srivatsa Vaddagiri
13 * Copyright IBM Corporation, 2007
14 * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
15 *
16 * Scaled math optimizations by Thomas Gleixner
17 * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de>
18 *
19 * Adaptive scheduling granularity, math enhancements by Peter Zijlstra
20 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
21 */
22
23#include <linux/latencytop.h>
24#include <linux/sched.h>
25#include <linux/cpumask.h>
26#include <linux/slab.h>
27#include <linux/profile.h>
28#include <linux/interrupt.h>
29
30#include <trace/events/sched.h>
31
32#include "sched.h"
33
34/*
35 * Targeted preemption latency for CPU-bound tasks:
36 * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
37 *
38 * NOTE: this latency value is not the same as the concept of
39 * 'timeslice length' - timeslices in CFS are of variable length
40 * and have no persistent notion like in traditional, time-slice
41 * based scheduling concepts.
42 *
43 * (to see the precise effective timeslice length of your workload,
44 * run vmstat and monitor the context-switches (cs) field)
45 */
46unsigned int sysctl_sched_latency = 6000000ULL;
47unsigned int normalized_sysctl_sched_latency = 6000000ULL;
48
49/*
50 * The initial- and re-scaling of tunables is configurable
51 * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
52 *
53 * Options are:
54 * SCHED_TUNABLESCALING_NONE - unscaled, always *1
55 * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
56 * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
57 */
58enum sched_tunable_scaling sysctl_sched_tunable_scaling
59 = SCHED_TUNABLESCALING_LOG;
60
61/*
62 * Minimal preemption granularity for CPU-bound tasks:
63 * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
64 */
65unsigned int sysctl_sched_min_granularity = 750000ULL;
66unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
67
68/*
69 * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
70 */
71static unsigned int sched_nr_latency = 8;
72
73/*
74 * After fork, child runs first. If set to 0 (default) then
75 * parent will (try to) run first.
76 */
77unsigned int sysctl_sched_child_runs_first __read_mostly;
78
79/*
80 * SCHED_OTHER wake-up granularity.
81 * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
82 *
83 * This option delays the preemption effects of decoupled workloads
84 * and reduces their over-scheduling. Synchronous workloads will still
85 * have immediate wakeup/sleep latencies.
86 */
87unsigned int sysctl_sched_wakeup_granularity = 1000000UL;
88unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
89
90const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
91
92/*
93 * The exponential sliding window over which load is averaged for shares
94 * distribution.
95 * (default: 10msec)
96 */
97unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
98
99#ifdef CONFIG_CFS_BANDWIDTH
100/*
101 * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
102 * each time a cfs_rq requests quota.
103 *
104 * Note: in the case that the slice exceeds the runtime remaining (either due
105 * to consumption or the quota being specified to be smaller than the slice)
106 * we will always only issue the remaining available time.
107 *
108 * default: 5 msec, units: microseconds
109 */
110unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
111#endif
112
113/*
114 * Increase the granularity value when there are more CPUs,
115 * because with more CPUs the 'effective latency' as visible
116 * to users decreases. But the relationship is not linear,
117 * so pick a second-best guess by going with the log2 of the
118 * number of CPUs.
119 *
120 * This idea comes from the SD scheduler of Con Kolivas:
121 */
122static int get_update_sysctl_factor(void)
123{
124 unsigned int cpus = min_t(int, num_online_cpus(), 8);
125 unsigned int factor;
126
127 switch (sysctl_sched_tunable_scaling) {
128 case SCHED_TUNABLESCALING_NONE:
129 factor = 1;
130 break;
131 case SCHED_TUNABLESCALING_LINEAR:
132 factor = cpus;
133 break;
134 case SCHED_TUNABLESCALING_LOG:
135 default:
136 factor = 1 + ilog2(cpus);
137 break;
138 }
139
140 return factor;
141}
142
143static void update_sysctl(void)
144{
145 unsigned int factor = get_update_sysctl_factor();
146
147#define SET_SYSCTL(name) \
148 (sysctl_##name = (factor) * normalized_sysctl_##name)
149 SET_SYSCTL(sched_min_granularity);
150 SET_SYSCTL(sched_latency);
151 SET_SYSCTL(sched_wakeup_granularity);
152#undef SET_SYSCTL
153}
154
155void sched_init_granularity(void)
156{
157 update_sysctl();
158}
159
160#if BITS_PER_LONG == 32
161# define WMULT_CONST (~0UL)
162#else
163# define WMULT_CONST (1UL << 32)
164#endif
165
166#define WMULT_SHIFT 32
167
168/*
169 * Shift right and round:
170 */
171#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
172
173/*
174 * delta *= weight / lw
175 */
176static unsigned long
177calc_delta_mine(unsigned long delta_exec, unsigned long weight,
178 struct load_weight *lw)
179{
180 u64 tmp;
181
182 /*
183 * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched
184 * entities since MIN_SHARES = 2. Treat weight as 1 if less than
185 * 2^SCHED_LOAD_RESOLUTION.
186 */
187 if (likely(weight > (1UL << SCHED_LOAD_RESOLUTION)))
188 tmp = (u64)delta_exec * scale_load_down(weight);
189 else
190 tmp = (u64)delta_exec;
191
192 if (!lw->inv_weight) {
193 unsigned long w = scale_load_down(lw->weight);
194
195 if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST))
196 lw->inv_weight = 1;
197 else if (unlikely(!w))
198 lw->inv_weight = WMULT_CONST;
199 else
200 lw->inv_weight = WMULT_CONST / w;
201 }
202
203 /*
204 * Check whether we'd overflow the 64-bit multiplication:
205 */
206 if (unlikely(tmp > WMULT_CONST))
207 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
208 WMULT_SHIFT/2);
209 else
210 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
211
212 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
213}
214
215
216const struct sched_class fair_sched_class;
217
218/**************************************************************
219 * CFS operations on generic schedulable entities:
220 */
221
222#ifdef CONFIG_FAIR_GROUP_SCHED
223
224/* cpu runqueue to which this cfs_rq is attached */
225static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
226{
227 return cfs_rq->rq;
228}
229
230/* An entity is a task if it doesn't "own" a runqueue */
231#define entity_is_task(se) (!se->my_q)
232
233static inline struct task_struct *task_of(struct sched_entity *se)
234{
235#ifdef CONFIG_SCHED_DEBUG
236 WARN_ON_ONCE(!entity_is_task(se));
237#endif
238 return container_of(se, struct task_struct, se);
239}
240
241/* Walk up scheduling entities hierarchy */
242#define for_each_sched_entity(se) \
243 for (; se; se = se->parent)
244
245static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
246{
247 return p->se.cfs_rq;
248}
249
250/* runqueue on which this entity is (to be) queued */
251static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
252{
253 return se->cfs_rq;
254}
255
256/* runqueue "owned" by this group */
257static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
258{
259 return grp->my_q;
260}
261
262static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
263{
264 if (!cfs_rq->on_list) {
265 /*
266 * Ensure we either appear before our parent (if already
267 * enqueued) or force our parent to appear after us when it is
268 * enqueued. The fact that we always enqueue bottom-up
269 * reduces this to two cases.
270 */
271 if (cfs_rq->tg->parent &&
272 cfs_rq->tg->parent->cfs_rq[cpu_of(rq_of(cfs_rq))]->on_list) {
273 list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
274 &rq_of(cfs_rq)->leaf_cfs_rq_list);
275 } else {
276 list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
277 &rq_of(cfs_rq)->leaf_cfs_rq_list);
278 }
279
280 cfs_rq->on_list = 1;
281 }
282}
283
284static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
285{
286 if (cfs_rq->on_list) {
287 list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
288 cfs_rq->on_list = 0;
289 }
290}
291
292/* Iterate thr' all leaf cfs_rq's on a runqueue */
293#define for_each_leaf_cfs_rq(rq, cfs_rq) \
294 list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
295
296/* Do the two (enqueued) entities belong to the same group ? */
297static inline int
298is_same_group(struct sched_entity *se, struct sched_entity *pse)
299{
300 if (se->cfs_rq == pse->cfs_rq)
301 return 1;
302
303 return 0;
304}
305
306static inline struct sched_entity *parent_entity(struct sched_entity *se)
307{
308 return se->parent;
309}
310
311/* return depth at which a sched entity is present in the hierarchy */
312static inline int depth_se(struct sched_entity *se)
313{
314 int depth = 0;
315
316 for_each_sched_entity(se)
317 depth++;
318
319 return depth;
320}
321
322static void
323find_matching_se(struct sched_entity **se, struct sched_entity **pse)
324{
325 int se_depth, pse_depth;
326
327 /*
328 * preemption test can be made between sibling entities who are in the
329 * same cfs_rq i.e who have a common parent. Walk up the hierarchy of
330 * both tasks until we find their ancestors who are siblings of common
331 * parent.
332 */
333
334 /* First walk up until both entities are at same depth */
335 se_depth = depth_se(*se);
336 pse_depth = depth_se(*pse);
337
338 while (se_depth > pse_depth) {
339 se_depth--;
340 *se = parent_entity(*se);
341 }
342
343 while (pse_depth > se_depth) {
344 pse_depth--;
345 *pse = parent_entity(*pse);
346 }
347
348 while (!is_same_group(*se, *pse)) {
349 *se = parent_entity(*se);
350 *pse = parent_entity(*pse);
351 }
352}
353
354#else /* !CONFIG_FAIR_GROUP_SCHED */
355
356static inline struct task_struct *task_of(struct sched_entity *se)
357{
358 return container_of(se, struct task_struct, se);
359}
360
361static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
362{
363 return container_of(cfs_rq, struct rq, cfs);
364}
365
366#define entity_is_task(se) 1
367
368#define for_each_sched_entity(se) \
369 for (; se; se = NULL)
370
371static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)
372{
373 return &task_rq(p)->cfs;
374}
375
376static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)
377{
378 struct task_struct *p = task_of(se);
379 struct rq *rq = task_rq(p);
380
381 return &rq->cfs;
382}
383
384/* runqueue "owned" by this group */
385static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
386{
387 return NULL;
388}
389
390static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
391{
392}
393
394static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
395{
396}
397
398#define for_each_leaf_cfs_rq(rq, cfs_rq) \
399 for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL)
400
401static inline int
402is_same_group(struct sched_entity *se, struct sched_entity *pse)
403{
404 return 1;
405}
406
407static inline struct sched_entity *parent_entity(struct sched_entity *se)
408{
409 return NULL;
410}
411
412static inline void
413find_matching_se(struct sched_entity **se, struct sched_entity **pse)
414{
415}
416
417#endif /* CONFIG_FAIR_GROUP_SCHED */
418
419static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
420 unsigned long delta_exec);
421
422/**************************************************************
423 * Scheduling class tree data structure manipulation methods:
424 */
425
426static inline u64 max_vruntime(u64 min_vruntime, u64 vruntime)
427{
428 s64 delta = (s64)(vruntime - min_vruntime);
429 if (delta > 0)
430 min_vruntime = vruntime;
431
432 return min_vruntime;
433}
434
435static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime)
436{
437 s64 delta = (s64)(vruntime - min_vruntime);
438 if (delta < 0)
439 min_vruntime = vruntime;
440
441 return min_vruntime;
442}
443
444static inline int entity_before(struct sched_entity *a,
445 struct sched_entity *b)
446{
447 return (s64)(a->vruntime - b->vruntime) < 0;
448}
449
450static void update_min_vruntime(struct cfs_rq *cfs_rq)
451{
452 u64 vruntime = cfs_rq->min_vruntime;
453
454 if (cfs_rq->curr)
455 vruntime = cfs_rq->curr->vruntime;
456
457 if (cfs_rq->rb_leftmost) {
458 struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost,
459 struct sched_entity,
460 run_node);
461
462 if (!cfs_rq->curr)
463 vruntime = se->vruntime;
464 else
465 vruntime = min_vruntime(vruntime, se->vruntime);
466 }
467
468 cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime);
469#ifndef CONFIG_64BIT
470 smp_wmb();
471 cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
472#endif
473}
474
475/*
476 * Enqueue an entity into the rb-tree:
477 */
478static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
479{
480 struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
481 struct rb_node *parent = NULL;
482 struct sched_entity *entry;
483 int leftmost = 1;
484
485 /*
486 * Find the right place in the rbtree:
487 */
488 while (*link) {
489 parent = *link;
490 entry = rb_entry(parent, struct sched_entity, run_node);
491 /*
492 * We dont care about collisions. Nodes with
493 * the same key stay together.
494 */
495 if (entity_before(se, entry)) {
496 link = &parent->rb_left;
497 } else {
498 link = &parent->rb_right;
499 leftmost = 0;
500 }
501 }
502
503 /*
504 * Maintain a cache of leftmost tree entries (it is frequently
505 * used):
506 */
507 if (leftmost)
508 cfs_rq->rb_leftmost = &se->run_node;
509
510 rb_link_node(&se->run_node, parent, link);
511 rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
512}
513
514static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
515{
516 if (cfs_rq->rb_leftmost == &se->run_node) {
517 struct rb_node *next_node;
518
519 next_node = rb_next(&se->run_node);
520 cfs_rq->rb_leftmost = next_node;
521 }
522
523 rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
524}
525
526struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
527{
528 struct rb_node *left = cfs_rq->rb_leftmost;
529
530 if (!left)
531 return NULL;
532
533 return rb_entry(left, struct sched_entity, run_node);
534}
535
536static struct sched_entity *__pick_next_entity(struct sched_entity *se)
537{
538 struct rb_node *next = rb_next(&se->run_node);
539
540 if (!next)
541 return NULL;
542
543 return rb_entry(next, struct sched_entity, run_node);
544}
545
546#ifdef CONFIG_SCHED_DEBUG
547struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
548{
549 struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
550
551 if (!last)
552 return NULL;
553
554 return rb_entry(last, struct sched_entity, run_node);
555}
556
557/**************************************************************
558 * Scheduling class statistics methods:
559 */
560
561int sched_proc_update_handler(struct ctl_table *table, int write,
562 void __user *buffer, size_t *lenp,
563 loff_t *ppos)
564{
565 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
566 int factor = get_update_sysctl_factor();
567
568 if (ret || !write)
569 return ret;
570
571 sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency,
572 sysctl_sched_min_granularity);
573
574#define WRT_SYSCTL(name) \
575 (normalized_sysctl_##name = sysctl_##name / (factor))
576 WRT_SYSCTL(sched_min_granularity);
577 WRT_SYSCTL(sched_latency);
578 WRT_SYSCTL(sched_wakeup_granularity);
579#undef WRT_SYSCTL
580
581 return 0;
582}
583#endif
584
585/*
586 * delta /= w
587 */
588static inline unsigned long
589calc_delta_fair(unsigned long delta, struct sched_entity *se)
590{
591 if (unlikely(se->load.weight != NICE_0_LOAD))
592 delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load);
593
594 return delta;
595}
596
597/*
598 * The idea is to set a period in which each task runs once.
599 *
600 * When there are too many tasks (sysctl_sched_nr_latency) we have to stretch
601 * this period because otherwise the slices get too small.
602 *
603 * p = (nr <= nl) ? l : l*nr/nl
604 */
605static u64 __sched_period(unsigned long nr_running)
606{
607 u64 period = sysctl_sched_latency;
608 unsigned long nr_latency = sched_nr_latency;
609
610 if (unlikely(nr_running > nr_latency)) {
611 period = sysctl_sched_min_granularity;
612 period *= nr_running;
613 }
614
615 return period;
616}
617
618/*
619 * We calculate the wall-time slice from the period by taking a part
620 * proportional to the weight.
621 *
622 * s = p*P[w/rw]
623 */
624static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
625{
626 u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
627
628 for_each_sched_entity(se) {
629 struct load_weight *load;
630 struct load_weight lw;
631
632 cfs_rq = cfs_rq_of(se);
633 load = &cfs_rq->load;
634
635 if (unlikely(!se->on_rq)) {
636 lw = cfs_rq->load;
637
638 update_load_add(&lw, se->load.weight);
639 load = &lw;
640 }
641 slice = calc_delta_mine(slice, se->load.weight, load);
642 }
643 return slice;
644}
645
646/*
647 * We calculate the vruntime slice of a to be inserted task
648 *
649 * vs = s/w
650 */
651static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
652{
653 return calc_delta_fair(sched_slice(cfs_rq, se), se);
654}
655
656static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update);
657static void update_cfs_shares(struct cfs_rq *cfs_rq);
658
659/*
660 * Update the current task's runtime statistics. Skip current tasks that
661 * are not in our scheduling class.
662 */
663static inline void
664__update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr,
665 unsigned long delta_exec)
666{
667 unsigned long delta_exec_weighted;
668
669 schedstat_set(curr->statistics.exec_max,
670 max((u64)delta_exec, curr->statistics.exec_max));
671
672 curr->sum_exec_runtime += delta_exec;
673 schedstat_add(cfs_rq, exec_clock, delta_exec);
674 delta_exec_weighted = calc_delta_fair(delta_exec, curr);
675
676 curr->vruntime += delta_exec_weighted;
677 update_min_vruntime(cfs_rq);
678
679#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
680 cfs_rq->load_unacc_exec_time += delta_exec;
681#endif
682}
683
684static void update_curr(struct cfs_rq *cfs_rq)
685{
686 struct sched_entity *curr = cfs_rq->curr;
687 u64 now = rq_of(cfs_rq)->clock_task;
688 unsigned long delta_exec;
689
690 if (unlikely(!curr))
691 return;
692
693 /*
694 * Get the amount of time the current task was running
695 * since the last time we changed load (this cannot
696 * overflow on 32 bits):
697 */
698 delta_exec = (unsigned long)(now - curr->exec_start);
699 if (!delta_exec)
700 return;
701
702 __update_curr(cfs_rq, curr, delta_exec);
703 curr->exec_start = now;
704
705 if (entity_is_task(curr)) {
706 struct task_struct *curtask = task_of(curr);
707
708 trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
709 cpuacct_charge(curtask, delta_exec);
710 account_group_exec_runtime(curtask, delta_exec);
711 }
712
713 account_cfs_rq_runtime(cfs_rq, delta_exec);
714}
715
716static inline void
717update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
718{
719 schedstat_set(se->statistics.wait_start, rq_of(cfs_rq)->clock);
720}
721
722/*
723 * Task is being enqueued - update stats:
724 */
725static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
726{
727 /*
728 * Are we enqueueing a waiting task? (for current tasks
729 * a dequeue/enqueue event is a NOP)
730 */
731 if (se != cfs_rq->curr)
732 update_stats_wait_start(cfs_rq, se);
733}
734
735static void
736update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
737{
738 schedstat_set(se->statistics.wait_max, max(se->statistics.wait_max,
739 rq_of(cfs_rq)->clock - se->statistics.wait_start));
740 schedstat_set(se->statistics.wait_count, se->statistics.wait_count + 1);
741 schedstat_set(se->statistics.wait_sum, se->statistics.wait_sum +
742 rq_of(cfs_rq)->clock - se->statistics.wait_start);
743#ifdef CONFIG_SCHEDSTATS
744 if (entity_is_task(se)) {
745 trace_sched_stat_wait(task_of(se),
746 rq_of(cfs_rq)->clock - se->statistics.wait_start);
747 }
748#endif
749 schedstat_set(se->statistics.wait_start, 0);
750}
751
752static inline void
753update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
754{
755 /*
756 * Mark the end of the wait period if dequeueing a
757 * waiting task:
758 */
759 if (se != cfs_rq->curr)
760 update_stats_wait_end(cfs_rq, se);
761}
762
763/*
764 * We are picking a new current task - update its stats:
765 */
766static inline void
767update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
768{
769 /*
770 * We are starting a new run period:
771 */
772 se->exec_start = rq_of(cfs_rq)->clock_task;
773}
774
775/**************************************************
776 * Scheduling class queueing methods:
777 */
778
779#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
780static void
781add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight)
782{
783 cfs_rq->task_weight += weight;
784}
785#else
786static inline void
787add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight)
788{
789}
790#endif
791
792static void
793account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
794{
795 update_load_add(&cfs_rq->load, se->load.weight);
796 if (!parent_entity(se))
797 update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
798 if (entity_is_task(se)) {
799 add_cfs_task_weight(cfs_rq, se->load.weight);
800 list_add(&se->group_node, &cfs_rq->tasks);
801 }
802 cfs_rq->nr_running++;
803}
804
805static void
806account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
807{
808 update_load_sub(&cfs_rq->load, se->load.weight);
809 if (!parent_entity(se))
810 update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
811 if (entity_is_task(se)) {
812 add_cfs_task_weight(cfs_rq, -se->load.weight);
813 list_del_init(&se->group_node);
814 }
815 cfs_rq->nr_running--;
816}
817
818#ifdef CONFIG_FAIR_GROUP_SCHED
819/* we need this in update_cfs_load and load-balance functions below */
820static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);
821# ifdef CONFIG_SMP
822static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
823 int global_update)
824{
825 struct task_group *tg = cfs_rq->tg;
826 long load_avg;
827
828 load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
829 load_avg -= cfs_rq->load_contribution;
830
831 if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) {
832 atomic_add(load_avg, &tg->load_weight);
833 cfs_rq->load_contribution += load_avg;
834 }
835}
836
837static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
838{
839 u64 period = sysctl_sched_shares_window;
840 u64 now, delta;
841 unsigned long load = cfs_rq->load.weight;
842
843 if (cfs_rq->tg == &root_task_group || throttled_hierarchy(cfs_rq))
844 return;
845
846 now = rq_of(cfs_rq)->clock_task;
847 delta = now - cfs_rq->load_stamp;
848
849 /* truncate load history at 4 idle periods */
850 if (cfs_rq->load_stamp > cfs_rq->load_last &&
851 now - cfs_rq->load_last > 4 * period) {
852 cfs_rq->load_period = 0;
853 cfs_rq->load_avg = 0;
854 delta = period - 1;
855 }
856
857 cfs_rq->load_stamp = now;
858 cfs_rq->load_unacc_exec_time = 0;
859 cfs_rq->load_period += delta;
860 if (load) {
861 cfs_rq->load_last = now;
862 cfs_rq->load_avg += delta * load;
863 }
864
865 /* consider updating load contribution on each fold or truncate */
866 if (global_update || cfs_rq->load_period > period
867 || !cfs_rq->load_period)
868 update_cfs_rq_load_contribution(cfs_rq, global_update);
869
870 while (cfs_rq->load_period > period) {
871 /*
872 * Inline assembly required to prevent the compiler
873 * optimising this loop into a divmod call.
874 * See __iter_div_u64_rem() for another example of this.
875 */
876 asm("" : "+rm" (cfs_rq->load_period));
877 cfs_rq->load_period /= 2;
878 cfs_rq->load_avg /= 2;
879 }
880
881 if (!cfs_rq->curr && !cfs_rq->nr_running && !cfs_rq->load_avg)
882 list_del_leaf_cfs_rq(cfs_rq);
883}
884
885static inline long calc_tg_weight(struct task_group *tg, struct cfs_rq *cfs_rq)
886{
887 long tg_weight;
888
889 /*
890 * Use this CPU's actual weight instead of the last load_contribution
891 * to gain a more accurate current total weight. See
892 * update_cfs_rq_load_contribution().
893 */
894 tg_weight = atomic_read(&tg->load_weight);
895 tg_weight -= cfs_rq->load_contribution;
896 tg_weight += cfs_rq->load.weight;
897
898 return tg_weight;
899}
900
901static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
902{
903 long tg_weight, load, shares;
904
905 tg_weight = calc_tg_weight(tg, cfs_rq);
906 load = cfs_rq->load.weight;
907
908 shares = (tg->shares * load);
909 if (tg_weight)
910 shares /= tg_weight;
911
912 if (shares < MIN_SHARES)
913 shares = MIN_SHARES;
914 if (shares > tg->shares)
915 shares = tg->shares;
916
917 return shares;
918}
919
920static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
921{
922 if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
923 update_cfs_load(cfs_rq, 0);
924 update_cfs_shares(cfs_rq);
925 }
926}
927# else /* CONFIG_SMP */
928static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
929{
930}
931
932static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
933{
934 return tg->shares;
935}
936
937static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
938{
939}
940# endif /* CONFIG_SMP */
941static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
942 unsigned long weight)
943{
944 if (se->on_rq) {
945 /* commit outstanding execution time */
946 if (cfs_rq->curr == se)
947 update_curr(cfs_rq);
948 account_entity_dequeue(cfs_rq, se);
949 }
950
951 update_load_set(&se->load, weight);
952
953 if (se->on_rq)
954 account_entity_enqueue(cfs_rq, se);
955}
956
957static void update_cfs_shares(struct cfs_rq *cfs_rq)
958{
959 struct task_group *tg;
960 struct sched_entity *se;
961 long shares;
962
963 tg = cfs_rq->tg;
964 se = tg->se[cpu_of(rq_of(cfs_rq))];
965 if (!se || throttled_hierarchy(cfs_rq))
966 return;
967#ifndef CONFIG_SMP
968 if (likely(se->load.weight == tg->shares))
969 return;
970#endif
971 shares = calc_cfs_shares(cfs_rq, tg);
972
973 reweight_entity(cfs_rq_of(se), se, shares);
974}
975#else /* CONFIG_FAIR_GROUP_SCHED */
976static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
977{
978}
979
980static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
981{
982}
983
984static inline void update_entity_shares_tick(struct cfs_rq *cfs_rq)
985{
986}
987#endif /* CONFIG_FAIR_GROUP_SCHED */
988
989static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
990{
991#ifdef CONFIG_SCHEDSTATS
992 struct task_struct *tsk = NULL;
993
994 if (entity_is_task(se))
995 tsk = task_of(se);
996
997 if (se->statistics.sleep_start) {
998 u64 delta = rq_of(cfs_rq)->clock - se->statistics.sleep_start;
999
1000 if ((s64)delta < 0)
1001 delta = 0;
1002
1003 if (unlikely(delta > se->statistics.sleep_max))
1004 se->statistics.sleep_max = delta;
1005
1006 se->statistics.sleep_start = 0;
1007 se->statistics.sum_sleep_runtime += delta;
1008
1009 if (tsk) {
1010 account_scheduler_latency(tsk, delta >> 10, 1);
1011 trace_sched_stat_sleep(tsk, delta);
1012 }
1013 }
1014 if (se->statistics.block_start) {
1015 u64 delta = rq_of(cfs_rq)->clock - se->statistics.block_start;
1016
1017 if ((s64)delta < 0)
1018 delta = 0;
1019
1020 if (unlikely(delta > se->statistics.block_max))
1021 se->statistics.block_max = delta;
1022
1023 se->statistics.block_start = 0;
1024 se->statistics.sum_sleep_runtime += delta;
1025
1026 if (tsk) {
1027 if (tsk->in_iowait) {
1028 se->statistics.iowait_sum += delta;
1029 se->statistics.iowait_count++;
1030 trace_sched_stat_iowait(tsk, delta);
1031 }
1032
1033 trace_sched_stat_blocked(tsk, delta);
1034
1035 /*
1036 * Blocking time is in units of nanosecs, so shift by
1037 * 20 to get a milliseconds-range estimation of the
1038 * amount of time that the task spent sleeping:
1039 */
1040 if (unlikely(prof_on == SLEEP_PROFILING)) {
1041 profile_hits(SLEEP_PROFILING,
1042 (void *)get_wchan(tsk),
1043 delta >> 20);
1044 }
1045 account_scheduler_latency(tsk, delta >> 10, 0);
1046 }
1047 }
1048#endif
1049}
1050
1051static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
1052{
1053#ifdef CONFIG_SCHED_DEBUG
1054 s64 d = se->vruntime - cfs_rq->min_vruntime;
1055
1056 if (d < 0)
1057 d = -d;
1058
1059 if (d > 3*sysctl_sched_latency)
1060 schedstat_inc(cfs_rq, nr_spread_over);
1061#endif
1062}
1063
1064static void
1065place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
1066{
1067 u64 vruntime = cfs_rq->min_vruntime;
1068
1069 /*
1070 * The 'current' period is already promised to the current tasks,
1071 * however the extra weight of the new task will slow them down a
1072 * little, place the new task so that it fits in the slot that
1073 * stays open at the end.
1074 */
1075 if (initial && sched_feat(START_DEBIT))
1076 vruntime += sched_vslice(cfs_rq, se);
1077
1078 /* sleeps up to a single latency don't count. */
1079 if (!initial) {
1080 unsigned long thresh = sysctl_sched_latency;
1081
1082 /*
1083 * Halve their sleep time's effect, to allow
1084 * for a gentler effect of sleepers:
1085 */
1086 if (sched_feat(GENTLE_FAIR_SLEEPERS))
1087 thresh >>= 1;
1088
1089 vruntime -= thresh;
1090 }
1091
1092 /* ensure we never gain time by being placed backwards. */
1093 vruntime = max_vruntime(se->vruntime, vruntime);
1094
1095 se->vruntime = vruntime;
1096}
1097
1098static void check_enqueue_throttle(struct cfs_rq *cfs_rq);
1099
1100static void
1101enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
1102{
1103 /*
1104 * Update the normalized vruntime before updating min_vruntime
1105 * through callig update_curr().
1106 */
1107 if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
1108 se->vruntime += cfs_rq->min_vruntime;
1109
1110 /*
1111 * Update run-time statistics of the 'current'.
1112 */
1113 update_curr(cfs_rq);
1114 update_cfs_load(cfs_rq, 0);
1115 account_entity_enqueue(cfs_rq, se);
1116 update_cfs_shares(cfs_rq);
1117
1118 if (flags & ENQUEUE_WAKEUP) {
1119 place_entity(cfs_rq, se, 0);
1120 enqueue_sleeper(cfs_rq, se);
1121 }
1122
1123 update_stats_enqueue(cfs_rq, se);
1124 check_spread(cfs_rq, se);
1125 if (se != cfs_rq->curr)
1126 __enqueue_entity(cfs_rq, se);
1127 se->on_rq = 1;
1128
1129 if (cfs_rq->nr_running == 1) {
1130 list_add_leaf_cfs_rq(cfs_rq);
1131 check_enqueue_throttle(cfs_rq);
1132 }
1133}
1134
1135static void __clear_buddies_last(struct sched_entity *se)
1136{
1137 for_each_sched_entity(se) {
1138 struct cfs_rq *cfs_rq = cfs_rq_of(se);
1139 if (cfs_rq->last == se)
1140 cfs_rq->last = NULL;
1141 else
1142 break;
1143 }
1144}
1145
1146static void __clear_buddies_next(struct sched_entity *se)
1147{
1148 for_each_sched_entity(se) {
1149 struct cfs_rq *cfs_rq = cfs_rq_of(se);
1150 if (cfs_rq->next == se)
1151 cfs_rq->next = NULL;
1152 else
1153 break;
1154 }
1155}
1156
1157static void __clear_buddies_skip(struct sched_entity *se)
1158{
1159 for_each_sched_entity(se) {
1160 struct cfs_rq *cfs_rq = cfs_rq_of(se);
1161 if (cfs_rq->skip == se)
1162 cfs_rq->skip = NULL;
1163 else
1164 break;
1165 }
1166}
1167
1168static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
1169{
1170 if (cfs_rq->last == se)
1171 __clear_buddies_last(se);
1172
1173 if (cfs_rq->next == se)
1174 __clear_buddies_next(se);
1175
1176 if (cfs_rq->skip == se)
1177 __clear_buddies_skip(se);
1178}
1179
1180static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
1181
1182static void
1183dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
1184{
1185 /*
1186 * Update run-time statistics of the 'current'.
1187 */
1188 update_curr(cfs_rq);
1189
1190 update_stats_dequeue(cfs_rq, se);
1191 if (flags & DEQUEUE_SLEEP) {
1192#ifdef CONFIG_SCHEDSTATS
1193 if (entity_is_task(se)) {
1194 struct task_struct *tsk = task_of(se);
1195
1196 if (tsk->state & TASK_INTERRUPTIBLE)
1197 se->statistics.sleep_start = rq_of(cfs_rq)->clock;
1198 if (tsk->state & TASK_UNINTERRUPTIBLE)
1199 se->statistics.block_start = rq_of(cfs_rq)->clock;
1200 }
1201#endif
1202 }
1203
1204 clear_buddies(cfs_rq, se);
1205
1206 if (se != cfs_rq->curr)
1207 __dequeue_entity(cfs_rq, se);
1208 se->on_rq = 0;
1209 update_cfs_load(cfs_rq, 0);
1210 account_entity_dequeue(cfs_rq, se);
1211
1212 /*
1213 * Normalize the entity after updating the min_vruntime because the
1214 * update can refer to the ->curr item and we need to reflect this
1215 * movement in our normalized position.
1216 */
1217 if (!(flags & DEQUEUE_SLEEP))
1218 se->vruntime -= cfs_rq->min_vruntime;
1219
1220 /* return excess runtime on last dequeue */
1221 return_cfs_rq_runtime(cfs_rq);
1222
1223 update_min_vruntime(cfs_rq);
1224 update_cfs_shares(cfs_rq);
1225}
1226
1227/*
1228 * Preempt the current task with a newly woken task if needed:
1229 */
1230static void
1231check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
1232{
1233 unsigned long ideal_runtime, delta_exec;
1234 struct sched_entity *se;
1235 s64 delta;
1236
1237 ideal_runtime = sched_slice(cfs_rq, curr);
1238 delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
1239 if (delta_exec > ideal_runtime) {
1240 resched_task(rq_of(cfs_rq)->curr);
1241 /*
1242 * The current task ran long enough, ensure it doesn't get
1243 * re-elected due to buddy favours.
1244 */
1245 clear_buddies(cfs_rq, curr);
1246 return;
1247 }
1248
1249 /*
1250 * Ensure that a task that missed wakeup preemption by a
1251 * narrow margin doesn't have to wait for a full slice.
1252 * This also mitigates buddy induced latencies under load.
1253 */
1254 if (delta_exec < sysctl_sched_min_granularity)
1255 return;
1256
1257 se = __pick_first_entity(cfs_rq);
1258 delta = curr->vruntime - se->vruntime;
1259
1260 if (delta < 0)
1261 return;
1262
1263 if (delta > ideal_runtime)
1264 resched_task(rq_of(cfs_rq)->curr);
1265}
1266
1267static void
1268set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
1269{
1270 /* 'current' is not kept within the tree. */
1271 if (se->on_rq) {
1272 /*
1273 * Any task has to be enqueued before it get to execute on
1274 * a CPU. So account for the time it spent waiting on the
1275 * runqueue.
1276 */
1277 update_stats_wait_end(cfs_rq, se);
1278 __dequeue_entity(cfs_rq, se);
1279 }
1280
1281 update_stats_curr_start(cfs_rq, se);
1282 cfs_rq->curr = se;
1283#ifdef CONFIG_SCHEDSTATS
1284 /*
1285 * Track our maximum slice length, if the CPU's load is at
1286 * least twice that of our own weight (i.e. dont track it
1287 * when there are only lesser-weight tasks around):
1288 */
1289 if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
1290 se->statistics.slice_max = max(se->statistics.slice_max,
1291 se->sum_exec_runtime - se->prev_sum_exec_runtime);
1292 }
1293#endif
1294 se->prev_sum_exec_runtime = se->sum_exec_runtime;
1295}
1296
1297static int
1298wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
1299
1300/*
1301 * Pick the next process, keeping these things in mind, in this order:
1302 * 1) keep things fair between processes/task groups
1303 * 2) pick the "next" process, since someone really wants that to run
1304 * 3) pick the "last" process, for cache locality
1305 * 4) do not run the "skip" process, if something else is available
1306 */
1307static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
1308{
1309 struct sched_entity *se = __pick_first_entity(cfs_rq);
1310 struct sched_entity *left = se;
1311
1312 /*
1313 * Avoid running the skip buddy, if running something else can
1314 * be done without getting too unfair.
1315 */
1316 if (cfs_rq->skip == se) {
1317 struct sched_entity *second = __pick_next_entity(se);
1318 if (second && wakeup_preempt_entity(second, left) < 1)
1319 se = second;
1320 }
1321
1322 /*
1323 * Prefer last buddy, try to return the CPU to a preempted task.
1324 */
1325 if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
1326 se = cfs_rq->last;
1327
1328 /*
1329 * Someone really wants this to run. If it's not unfair, run it.
1330 */
1331 if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
1332 se = cfs_rq->next;
1333
1334 clear_buddies(cfs_rq, se);
1335
1336 return se;
1337}
1338
1339static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq);
1340
1341static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
1342{
1343 /*
1344 * If still on the runqueue then deactivate_task()
1345 * was not called and update_curr() has to be done:
1346 */
1347 if (prev->on_rq)
1348 update_curr(cfs_rq);
1349
1350 /* throttle cfs_rqs exceeding runtime */
1351 check_cfs_rq_runtime(cfs_rq);
1352
1353 check_spread(cfs_rq, prev);
1354 if (prev->on_rq) {
1355 update_stats_wait_start(cfs_rq, prev);
1356 /* Put 'current' back into the tree. */
1357 __enqueue_entity(cfs_rq, prev);
1358 }
1359 cfs_rq->curr = NULL;
1360}
1361
1362static void
1363entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
1364{
1365 /*
1366 * Update run-time statistics of the 'current'.
1367 */
1368 update_curr(cfs_rq);
1369
1370 /*
1371 * Update share accounting for long-running entities.
1372 */
1373 update_entity_shares_tick(cfs_rq);
1374
1375#ifdef CONFIG_SCHED_HRTICK
1376 /*
1377 * queued ticks are scheduled to match the slice, so don't bother
1378 * validating it and just reschedule.
1379 */
1380 if (queued) {
1381 resched_task(rq_of(cfs_rq)->curr);
1382 return;
1383 }
1384 /*
1385 * don't let the period tick interfere with the hrtick preemption
1386 */
1387 if (!sched_feat(DOUBLE_TICK) &&
1388 hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
1389 return;
1390#endif
1391
1392 if (cfs_rq->nr_running > 1)
1393 check_preempt_tick(cfs_rq, curr);
1394}
1395
1396
1397/**************************************************
1398 * CFS bandwidth control machinery
1399 */
1400
1401#ifdef CONFIG_CFS_BANDWIDTH
1402
1403#ifdef HAVE_JUMP_LABEL
1404static struct jump_label_key __cfs_bandwidth_used;
1405
1406static inline bool cfs_bandwidth_used(void)
1407{
1408 return static_branch(&__cfs_bandwidth_used);
1409}
1410
1411void account_cfs_bandwidth_used(int enabled, int was_enabled)
1412{
1413 /* only need to count groups transitioning between enabled/!enabled */
1414 if (enabled && !was_enabled)
1415 jump_label_inc(&__cfs_bandwidth_used);
1416 else if (!enabled && was_enabled)
1417 jump_label_dec(&__cfs_bandwidth_used);
1418}
1419#else /* HAVE_JUMP_LABEL */
1420static bool cfs_bandwidth_used(void)
1421{
1422 return true;
1423}
1424
1425void account_cfs_bandwidth_used(int enabled, int was_enabled) {}
1426#endif /* HAVE_JUMP_LABEL */
1427
1428/*
1429 * default period for cfs group bandwidth.
1430 * default: 0.1s, units: nanoseconds
1431 */
1432static inline u64 default_cfs_period(void)
1433{
1434 return 100000000ULL;
1435}
1436
1437static inline u64 sched_cfs_bandwidth_slice(void)
1438{
1439 return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;
1440}
1441
1442/*
1443 * Replenish runtime according to assigned quota and update expiration time.
1444 * We use sched_clock_cpu directly instead of rq->clock to avoid adding
1445 * additional synchronization around rq->lock.
1446 *
1447 * requires cfs_b->lock
1448 */
1449void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
1450{
1451 u64 now;
1452
1453 if (cfs_b->quota == RUNTIME_INF)
1454 return;
1455
1456 now = sched_clock_cpu(smp_processor_id());
1457 cfs_b->runtime = cfs_b->quota;
1458 cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period);
1459}
1460
1461static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
1462{
1463 return &tg->cfs_bandwidth;
1464}
1465
1466/* returns 0 on failure to allocate runtime */
1467static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
1468{
1469 struct task_group *tg = cfs_rq->tg;
1470 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg);
1471 u64 amount = 0, min_amount, expires;
1472
1473 /* note: this is a positive sum as runtime_remaining <= 0 */
1474 min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining;
1475
1476 raw_spin_lock(&cfs_b->lock);
1477 if (cfs_b->quota == RUNTIME_INF)
1478 amount = min_amount;
1479 else {
1480 /*
1481 * If the bandwidth pool has become inactive, then at least one
1482 * period must have elapsed since the last consumption.
1483 * Refresh the global state and ensure bandwidth timer becomes
1484 * active.
1485 */
1486 if (!cfs_b->timer_active) {
1487 __refill_cfs_bandwidth_runtime(cfs_b);
1488 __start_cfs_bandwidth(cfs_b);
1489 }
1490
1491 if (cfs_b->runtime > 0) {
1492 amount = min(cfs_b->runtime, min_amount);
1493 cfs_b->runtime -= amount;
1494 cfs_b->idle = 0;
1495 }
1496 }
1497 expires = cfs_b->runtime_expires;
1498 raw_spin_unlock(&cfs_b->lock);
1499
1500 cfs_rq->runtime_remaining += amount;
1501 /*
1502 * we may have advanced our local expiration to account for allowed
1503 * spread between our sched_clock and the one on which runtime was
1504 * issued.
1505 */
1506 if ((s64)(expires - cfs_rq->runtime_expires) > 0)
1507 cfs_rq->runtime_expires = expires;
1508
1509 return cfs_rq->runtime_remaining > 0;
1510}
1511
1512/*
1513 * Note: This depends on the synchronization provided by sched_clock and the
1514 * fact that rq->clock snapshots this value.
1515 */
1516static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq)
1517{
1518 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
1519 struct rq *rq = rq_of(cfs_rq);
1520
1521 /* if the deadline is ahead of our clock, nothing to do */
1522 if (likely((s64)(rq->clock - cfs_rq->runtime_expires) < 0))
1523 return;
1524
1525 if (cfs_rq->runtime_remaining < 0)
1526 return;
1527
1528 /*
1529 * If the local deadline has passed we have to consider the
1530 * possibility that our sched_clock is 'fast' and the global deadline
1531 * has not truly expired.
1532 *
1533 * Fortunately we can check determine whether this the case by checking
1534 * whether the global deadline has advanced.
1535 */
1536
1537 if ((s64)(cfs_rq->runtime_expires - cfs_b->runtime_expires) >= 0) {
1538 /* extend local deadline, drift is bounded above by 2 ticks */
1539 cfs_rq->runtime_expires += TICK_NSEC;
1540 } else {
1541 /* global deadline is ahead, expiration has passed */
1542 cfs_rq->runtime_remaining = 0;
1543 }
1544}
1545
1546static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
1547 unsigned long delta_exec)
1548{
1549 /* dock delta_exec before expiring quota (as it could span periods) */
1550 cfs_rq->runtime_remaining -= delta_exec;
1551 expire_cfs_rq_runtime(cfs_rq);
1552
1553 if (likely(cfs_rq->runtime_remaining > 0))
1554 return;
1555
1556 /*
1557 * if we're unable to extend our runtime we resched so that the active
1558 * hierarchy can be throttled
1559 */
1560 if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
1561 resched_task(rq_of(cfs_rq)->curr);
1562}
1563
1564static __always_inline void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
1565 unsigned long delta_exec)
1566{
1567 if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled)
1568 return;
1569
1570 __account_cfs_rq_runtime(cfs_rq, delta_exec);
1571}
1572
1573static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
1574{
1575 return cfs_bandwidth_used() && cfs_rq->throttled;
1576}
1577
1578/* check whether cfs_rq, or any parent, is throttled */
1579static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
1580{
1581 return cfs_bandwidth_used() && cfs_rq->throttle_count;
1582}
1583
1584/*
1585 * Ensure that neither of the group entities corresponding to src_cpu or
1586 * dest_cpu are members of a throttled hierarchy when performing group
1587 * load-balance operations.
1588 */
1589static inline int throttled_lb_pair(struct task_group *tg,
1590 int src_cpu, int dest_cpu)
1591{
1592 struct cfs_rq *src_cfs_rq, *dest_cfs_rq;
1593
1594 src_cfs_rq = tg->cfs_rq[src_cpu];
1595 dest_cfs_rq = tg->cfs_rq[dest_cpu];
1596
1597 return throttled_hierarchy(src_cfs_rq) ||
1598 throttled_hierarchy(dest_cfs_rq);
1599}
1600
1601/* updated child weight may affect parent so we have to do this bottom up */
1602static int tg_unthrottle_up(struct task_group *tg, void *data)
1603{
1604 struct rq *rq = data;
1605 struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
1606
1607 cfs_rq->throttle_count--;
1608#ifdef CONFIG_SMP
1609 if (!cfs_rq->throttle_count) {
1610 u64 delta = rq->clock_task - cfs_rq->load_stamp;
1611
1612 /* leaving throttled state, advance shares averaging windows */
1613 cfs_rq->load_stamp += delta;
1614 cfs_rq->load_last += delta;
1615
1616 /* update entity weight now that we are on_rq again */
1617 update_cfs_shares(cfs_rq);
1618 }
1619#endif
1620
1621 return 0;
1622}
1623
1624static int tg_throttle_down(struct task_group *tg, void *data)
1625{
1626 struct rq *rq = data;
1627 struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
1628
1629 /* group is entering throttled state, record last load */
1630 if (!cfs_rq->throttle_count)
1631 update_cfs_load(cfs_rq, 0);
1632 cfs_rq->throttle_count++;
1633
1634 return 0;
1635}
1636
1637static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
1638{
1639 struct rq *rq = rq_of(cfs_rq);
1640 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
1641 struct sched_entity *se;
1642 long task_delta, dequeue = 1;
1643
1644 se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
1645
1646 /* account load preceding throttle */
1647 rcu_read_lock();
1648 walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
1649 rcu_read_unlock();
1650
1651 task_delta = cfs_rq->h_nr_running;
1652 for_each_sched_entity(se) {
1653 struct cfs_rq *qcfs_rq = cfs_rq_of(se);
1654 /* throttled entity or throttle-on-deactivate */
1655 if (!se->on_rq)
1656 break;
1657
1658 if (dequeue)
1659 dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP);
1660 qcfs_rq->h_nr_running -= task_delta;
1661
1662 if (qcfs_rq->load.weight)
1663 dequeue = 0;
1664 }
1665
1666 if (!se)
1667 rq->nr_running -= task_delta;
1668
1669 cfs_rq->throttled = 1;
1670 cfs_rq->throttled_timestamp = rq->clock;
1671 raw_spin_lock(&cfs_b->lock);
1672 list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
1673 raw_spin_unlock(&cfs_b->lock);
1674}
1675
1676void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
1677{
1678 struct rq *rq = rq_of(cfs_rq);
1679 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
1680 struct sched_entity *se;
1681 int enqueue = 1;
1682 long task_delta;
1683
1684 se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
1685
1686 cfs_rq->throttled = 0;
1687 raw_spin_lock(&cfs_b->lock);
1688 cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp;
1689 list_del_rcu(&cfs_rq->throttled_list);
1690 raw_spin_unlock(&cfs_b->lock);
1691 cfs_rq->throttled_timestamp = 0;
1692
1693 update_rq_clock(rq);
1694 /* update hierarchical throttle state */
1695 walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
1696
1697 if (!cfs_rq->load.weight)
1698 return;
1699
1700 task_delta = cfs_rq->h_nr_running;
1701 for_each_sched_entity(se) {
1702 if (se->on_rq)
1703 enqueue = 0;
1704
1705 cfs_rq = cfs_rq_of(se);
1706 if (enqueue)
1707 enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP);
1708 cfs_rq->h_nr_running += task_delta;
1709
1710 if (cfs_rq_throttled(cfs_rq))
1711 break;
1712 }
1713
1714 if (!se)
1715 rq->nr_running += task_delta;
1716
1717 /* determine whether we need to wake up potentially idle cpu */
1718 if (rq->curr == rq->idle && rq->cfs.nr_running)
1719 resched_task(rq->curr);
1720}
1721
1722static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
1723 u64 remaining, u64 expires)
1724{
1725 struct cfs_rq *cfs_rq;
1726 u64 runtime = remaining;
1727
1728 rcu_read_lock();
1729 list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
1730 throttled_list) {
1731 struct rq *rq = rq_of(cfs_rq);
1732
1733 raw_spin_lock(&rq->lock);
1734 if (!cfs_rq_throttled(cfs_rq))
1735 goto next;
1736
1737 runtime = -cfs_rq->runtime_remaining + 1;
1738 if (runtime > remaining)
1739 runtime = remaining;
1740 remaining -= runtime;
1741
1742 cfs_rq->runtime_remaining += runtime;
1743 cfs_rq->runtime_expires = expires;
1744
1745 /* we check whether we're throttled above */
1746 if (cfs_rq->runtime_remaining > 0)
1747 unthrottle_cfs_rq(cfs_rq);
1748
1749next:
1750 raw_spin_unlock(&rq->lock);
1751
1752 if (!remaining)
1753 break;
1754 }
1755 rcu_read_unlock();
1756
1757 return remaining;
1758}
1759
1760/*
1761 * Responsible for refilling a task_group's bandwidth and unthrottling its
1762 * cfs_rqs as appropriate. If there has been no activity within the last
1763 * period the timer is deactivated until scheduling resumes; cfs_b->idle is
1764 * used to track this state.
1765 */
1766static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
1767{
1768 u64 runtime, runtime_expires;
1769 int idle = 1, throttled;
1770
1771 raw_spin_lock(&cfs_b->lock);
1772 /* no need to continue the timer with no bandwidth constraint */
1773 if (cfs_b->quota == RUNTIME_INF)
1774 goto out_unlock;
1775
1776 throttled = !list_empty(&cfs_b->throttled_cfs_rq);
1777 /* idle depends on !throttled (for the case of a large deficit) */
1778 idle = cfs_b->idle && !throttled;
1779 cfs_b->nr_periods += overrun;
1780
1781 /* if we're going inactive then everything else can be deferred */
1782 if (idle)
1783 goto out_unlock;
1784
1785 __refill_cfs_bandwidth_runtime(cfs_b);
1786
1787 if (!throttled) {
1788 /* mark as potentially idle for the upcoming period */
1789 cfs_b->idle = 1;
1790 goto out_unlock;
1791 }
1792
1793 /* account preceding periods in which throttling occurred */
1794 cfs_b->nr_throttled += overrun;
1795
1796 /*
1797 * There are throttled entities so we must first use the new bandwidth
1798 * to unthrottle them before making it generally available. This
1799 * ensures that all existing debts will be paid before a new cfs_rq is
1800 * allowed to run.
1801 */
1802 runtime = cfs_b->runtime;
1803 runtime_expires = cfs_b->runtime_expires;
1804 cfs_b->runtime = 0;
1805
1806 /*
1807 * This check is repeated as we are holding onto the new bandwidth
1808 * while we unthrottle. This can potentially race with an unthrottled
1809 * group trying to acquire new bandwidth from the global pool.
1810 */
1811 while (throttled && runtime > 0) {
1812 raw_spin_unlock(&cfs_b->lock);
1813 /* we can't nest cfs_b->lock while distributing bandwidth */
1814 runtime = distribute_cfs_runtime(cfs_b, runtime,
1815 runtime_expires);
1816 raw_spin_lock(&cfs_b->lock);
1817
1818 throttled = !list_empty(&cfs_b->throttled_cfs_rq);
1819 }
1820
1821 /* return (any) remaining runtime */
1822 cfs_b->runtime = runtime;
1823 /*
1824 * While we are ensured activity in the period following an
1825 * unthrottle, this also covers the case in which the new bandwidth is
1826 * insufficient to cover the existing bandwidth deficit. (Forcing the
1827 * timer to remain active while there are any throttled entities.)
1828 */
1829 cfs_b->idle = 0;
1830out_unlock:
1831 if (idle)
1832 cfs_b->timer_active = 0;
1833 raw_spin_unlock(&cfs_b->lock);
1834
1835 return idle;
1836}
1837
1838/* a cfs_rq won't donate quota below this amount */
1839static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC;
1840/* minimum remaining period time to redistribute slack quota */
1841static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC;
1842/* how long we wait to gather additional slack before distributing */
1843static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
1844
1845/* are we near the end of the current quota period? */
1846static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
1847{
1848 struct hrtimer *refresh_timer = &cfs_b->period_timer;
1849 u64 remaining;
1850
1851 /* if the call-back is running a quota refresh is already occurring */
1852 if (hrtimer_callback_running(refresh_timer))
1853 return 1;
1854
1855 /* is a quota refresh about to occur? */
1856 remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
1857 if (remaining < min_expire)
1858 return 1;
1859
1860 return 0;
1861}
1862
1863static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
1864{
1865 u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration;
1866
1867 /* if there's a quota refresh soon don't bother with slack */
1868 if (runtime_refresh_within(cfs_b, min_left))
1869 return;
1870
1871 start_bandwidth_timer(&cfs_b->slack_timer,
1872 ns_to_ktime(cfs_bandwidth_slack_period));
1873}
1874
1875/* we know any runtime found here is valid as update_curr() precedes return */
1876static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
1877{
1878 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
1879 s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime;
1880
1881 if (slack_runtime <= 0)
1882 return;
1883
1884 raw_spin_lock(&cfs_b->lock);
1885 if (cfs_b->quota != RUNTIME_INF &&
1886 cfs_rq->runtime_expires == cfs_b->runtime_expires) {
1887 cfs_b->runtime += slack_runtime;
1888
1889 /* we are under rq->lock, defer unthrottling using a timer */
1890 if (cfs_b->runtime > sched_cfs_bandwidth_slice() &&
1891 !list_empty(&cfs_b->throttled_cfs_rq))
1892 start_cfs_slack_bandwidth(cfs_b);
1893 }
1894 raw_spin_unlock(&cfs_b->lock);
1895
1896 /* even if it's not valid for return we don't want to try again */
1897 cfs_rq->runtime_remaining -= slack_runtime;
1898}
1899
1900static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
1901{
1902 if (!cfs_bandwidth_used())
1903 return;
1904
1905 if (!cfs_rq->runtime_enabled || cfs_rq->nr_running)
1906 return;
1907
1908 __return_cfs_rq_runtime(cfs_rq);
1909}
1910
1911/*
1912 * This is done with a timer (instead of inline with bandwidth return) since
1913 * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs.
1914 */
1915static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
1916{
1917 u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
1918 u64 expires;
1919
1920 /* confirm we're still not at a refresh boundary */
1921 if (runtime_refresh_within(cfs_b, min_bandwidth_expiration))
1922 return;
1923
1924 raw_spin_lock(&cfs_b->lock);
1925 if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) {
1926 runtime = cfs_b->runtime;
1927 cfs_b->runtime = 0;
1928 }
1929 expires = cfs_b->runtime_expires;
1930 raw_spin_unlock(&cfs_b->lock);
1931
1932 if (!runtime)
1933 return;
1934
1935 runtime = distribute_cfs_runtime(cfs_b, runtime, expires);
1936
1937 raw_spin_lock(&cfs_b->lock);
1938 if (expires == cfs_b->runtime_expires)
1939 cfs_b->runtime = runtime;
1940 raw_spin_unlock(&cfs_b->lock);
1941}
1942
1943/*
1944 * When a group wakes up we want to make sure that its quota is not already
1945 * expired/exceeded, otherwise it may be allowed to steal additional ticks of
1946 * runtime as update_curr() throttling can not not trigger until it's on-rq.
1947 */
1948static void check_enqueue_throttle(struct cfs_rq *cfs_rq)
1949{
1950 if (!cfs_bandwidth_used())
1951 return;
1952
1953 /* an active group must be handled by the update_curr()->put() path */
1954 if (!cfs_rq->runtime_enabled || cfs_rq->curr)
1955 return;
1956
1957 /* ensure the group is not already throttled */
1958 if (cfs_rq_throttled(cfs_rq))
1959 return;
1960
1961 /* update runtime allocation */
1962 account_cfs_rq_runtime(cfs_rq, 0);
1963 if (cfs_rq->runtime_remaining <= 0)
1964 throttle_cfs_rq(cfs_rq);
1965}
1966
1967/* conditionally throttle active cfs_rq's from put_prev_entity() */
1968static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq)
1969{
1970 if (!cfs_bandwidth_used())
1971 return;
1972
1973 if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0))
1974 return;
1975
1976 /*
1977 * it's possible for a throttled entity to be forced into a running
1978 * state (e.g. set_curr_task), in this case we're finished.
1979 */
1980 if (cfs_rq_throttled(cfs_rq))
1981 return;
1982
1983 throttle_cfs_rq(cfs_rq);
1984}
1985
1986static inline u64 default_cfs_period(void);
1987static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun);
1988static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b);
1989
1990static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
1991{
1992 struct cfs_bandwidth *cfs_b =
1993 container_of(timer, struct cfs_bandwidth, slack_timer);
1994 do_sched_cfs_slack_timer(cfs_b);
1995
1996 return HRTIMER_NORESTART;
1997}
1998
1999static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
2000{
2001 struct cfs_bandwidth *cfs_b =
2002 container_of(timer, struct cfs_bandwidth, period_timer);
2003 ktime_t now;
2004 int overrun;
2005 int idle = 0;
2006
2007 for (;;) {
2008 now = hrtimer_cb_get_time(timer);
2009 overrun = hrtimer_forward(timer, now, cfs_b->period);
2010
2011 if (!overrun)
2012 break;
2013
2014 idle = do_sched_cfs_period_timer(cfs_b, overrun);
2015 }
2016
2017 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
2018}
2019
2020void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
2021{
2022 raw_spin_lock_init(&cfs_b->lock);
2023 cfs_b->runtime = 0;
2024 cfs_b->quota = RUNTIME_INF;
2025 cfs_b->period = ns_to_ktime(default_cfs_period());
2026
2027 INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
2028 hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2029 cfs_b->period_timer.function = sched_cfs_period_timer;
2030 hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2031 cfs_b->slack_timer.function = sched_cfs_slack_timer;
2032}
2033
2034static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
2035{
2036 cfs_rq->runtime_enabled = 0;
2037 INIT_LIST_HEAD(&cfs_rq->throttled_list);
2038}
2039
2040/* requires cfs_b->lock, may release to reprogram timer */
2041void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
2042{
2043 /*
2044 * The timer may be active because we're trying to set a new bandwidth
2045 * period or because we're racing with the tear-down path
2046 * (timer_active==0 becomes visible before the hrtimer call-back
2047 * terminates). In either case we ensure that it's re-programmed
2048 */
2049 while (unlikely(hrtimer_active(&cfs_b->period_timer))) {
2050 raw_spin_unlock(&cfs_b->lock);
2051 /* ensure cfs_b->lock is available while we wait */
2052 hrtimer_cancel(&cfs_b->period_timer);
2053
2054 raw_spin_lock(&cfs_b->lock);
2055 /* if someone else restarted the timer then we're done */
2056 if (cfs_b->timer_active)
2057 return;
2058 }
2059
2060 cfs_b->timer_active = 1;
2061 start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period);
2062}
2063
2064static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
2065{
2066 hrtimer_cancel(&cfs_b->period_timer);
2067 hrtimer_cancel(&cfs_b->slack_timer);
2068}
2069
2070void unthrottle_offline_cfs_rqs(struct rq *rq)
2071{
2072 struct cfs_rq *cfs_rq;
2073
2074 for_each_leaf_cfs_rq(rq, cfs_rq) {
2075 struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
2076
2077 if (!cfs_rq->runtime_enabled)
2078 continue;
2079
2080 /*
2081 * clock_task is not advancing so we just need to make sure
2082 * there's some valid quota amount
2083 */
2084 cfs_rq->runtime_remaining = cfs_b->quota;
2085 if (cfs_rq_throttled(cfs_rq))
2086 unthrottle_cfs_rq(cfs_rq);
2087 }
2088}
2089
2090#else /* CONFIG_CFS_BANDWIDTH */
2091static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,
2092 unsigned long delta_exec) {}
2093static void check_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
2094static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {}
2095static void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
2096
2097static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq)
2098{
2099 return 0;
2100}
2101
2102static inline int throttled_hierarchy(struct cfs_rq *cfs_rq)
2103{
2104 return 0;
2105}
2106
2107static inline int throttled_lb_pair(struct task_group *tg,
2108 int src_cpu, int dest_cpu)
2109{
2110 return 0;
2111}
2112
2113void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
2114
2115#ifdef CONFIG_FAIR_GROUP_SCHED
2116static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {}
2117#endif
2118
2119static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
2120{
2121 return NULL;
2122}
2123static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
2124void unthrottle_offline_cfs_rqs(struct rq *rq) {}
2125
2126#endif /* CONFIG_CFS_BANDWIDTH */
2127
2128/**************************************************
2129 * CFS operations on tasks:
2130 */
2131
2132#ifdef CONFIG_SCHED_HRTICK
2133static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
2134{
2135 struct sched_entity *se = &p->se;
2136 struct cfs_rq *cfs_rq = cfs_rq_of(se);
2137
2138 WARN_ON(task_rq(p) != rq);
2139
2140 if (cfs_rq->nr_running > 1) {
2141 u64 slice = sched_slice(cfs_rq, se);
2142 u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
2143 s64 delta = slice - ran;
2144
2145 if (delta < 0) {
2146 if (rq->curr == p)
2147 resched_task(p);
2148 return;
2149 }
2150
2151 /*
2152 * Don't schedule slices shorter than 10000ns, that just
2153 * doesn't make sense. Rely on vruntime for fairness.
2154 */
2155 if (rq->curr != p)
2156 delta = max_t(s64, 10000LL, delta);
2157
2158 hrtick_start(rq, delta);
2159 }
2160}
2161
2162/*
2163 * called from enqueue/dequeue and updates the hrtick when the
2164 * current task is from our class and nr_running is low enough
2165 * to matter.
2166 */
2167static void hrtick_update(struct rq *rq)
2168{
2169 struct task_struct *curr = rq->curr;
2170
2171 if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class)
2172 return;
2173
2174 if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
2175 hrtick_start_fair(rq, curr);
2176}
2177#else /* !CONFIG_SCHED_HRTICK */
2178static inline void
2179hrtick_start_fair(struct rq *rq, struct task_struct *p)
2180{
2181}
2182
2183static inline void hrtick_update(struct rq *rq)
2184{
2185}
2186#endif
2187
2188/*
2189 * The enqueue_task method is called before nr_running is
2190 * increased. Here we update the fair scheduling stats and
2191 * then put the task into the rbtree:
2192 */
2193static void
2194enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
2195{
2196 struct cfs_rq *cfs_rq;
2197 struct sched_entity *se = &p->se;
2198
2199 for_each_sched_entity(se) {
2200 if (se->on_rq)
2201 break;
2202 cfs_rq = cfs_rq_of(se);
2203 enqueue_entity(cfs_rq, se, flags);
2204
2205 /*
2206 * end evaluation on encountering a throttled cfs_rq
2207 *
2208 * note: in the case of encountering a throttled cfs_rq we will
2209 * post the final h_nr_running increment below.
2210 */
2211 if (cfs_rq_throttled(cfs_rq))
2212 break;
2213 cfs_rq->h_nr_running++;
2214
2215 flags = ENQUEUE_WAKEUP;
2216 }
2217
2218 for_each_sched_entity(se) {
2219 cfs_rq = cfs_rq_of(se);
2220 cfs_rq->h_nr_running++;
2221
2222 if (cfs_rq_throttled(cfs_rq))
2223 break;
2224
2225 update_cfs_load(cfs_rq, 0);
2226 update_cfs_shares(cfs_rq);
2227 }
2228
2229 if (!se)
2230 inc_nr_running(rq);
2231 hrtick_update(rq);
2232}
2233
2234static void set_next_buddy(struct sched_entity *se);
2235
2236/*
2237 * The dequeue_task method is called before nr_running is
2238 * decreased. We remove the task from the rbtree and
2239 * update the fair scheduling stats:
2240 */
2241static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
2242{
2243 struct cfs_rq *cfs_rq;
2244 struct sched_entity *se = &p->se;
2245 int task_sleep = flags & DEQUEUE_SLEEP;
2246
2247 for_each_sched_entity(se) {
2248 cfs_rq = cfs_rq_of(se);
2249 dequeue_entity(cfs_rq, se, flags);
2250
2251 /*
2252 * end evaluation on encountering a throttled cfs_rq
2253 *
2254 * note: in the case of encountering a throttled cfs_rq we will
2255 * post the final h_nr_running decrement below.
2256 */
2257 if (cfs_rq_throttled(cfs_rq))
2258 break;
2259 cfs_rq->h_nr_running--;
2260
2261 /* Don't dequeue parent if it has other entities besides us */
2262 if (cfs_rq->load.weight) {
2263 /*
2264 * Bias pick_next to pick a task from this cfs_rq, as
2265 * p is sleeping when it is within its sched_slice.
2266 */
2267 if (task_sleep && parent_entity(se))
2268 set_next_buddy(parent_entity(se));
2269
2270 /* avoid re-evaluating load for this entity */
2271 se = parent_entity(se);
2272 break;
2273 }
2274 flags |= DEQUEUE_SLEEP;
2275 }
2276
2277 for_each_sched_entity(se) {
2278 cfs_rq = cfs_rq_of(se);
2279 cfs_rq->h_nr_running--;
2280
2281 if (cfs_rq_throttled(cfs_rq))
2282 break;
2283
2284 update_cfs_load(cfs_rq, 0);
2285 update_cfs_shares(cfs_rq);
2286 }
2287
2288 if (!se)
2289 dec_nr_running(rq);
2290 hrtick_update(rq);
2291}
2292
2293#ifdef CONFIG_SMP
2294/* Used instead of source_load when we know the type == 0 */
2295static unsigned long weighted_cpuload(const int cpu)
2296{
2297 return cpu_rq(cpu)->load.weight;
2298}
2299
2300/*
2301 * Return a low guess at the load of a migration-source cpu weighted
2302 * according to the scheduling class and "nice" value.
2303 *
2304 * We want to under-estimate the load of migration sources, to
2305 * balance conservatively.
2306 */
2307static unsigned long source_load(int cpu, int type)
2308{
2309 struct rq *rq = cpu_rq(cpu);
2310 unsigned long total = weighted_cpuload(cpu);
2311
2312 if (type == 0 || !sched_feat(LB_BIAS))
2313 return total;
2314
2315 return min(rq->cpu_load[type-1], total);
2316}
2317
2318/*
2319 * Return a high guess at the load of a migration-target cpu weighted
2320 * according to the scheduling class and "nice" value.
2321 */
2322static unsigned long target_load(int cpu, int type)
2323{
2324 struct rq *rq = cpu_rq(cpu);
2325 unsigned long total = weighted_cpuload(cpu);
2326
2327 if (type == 0 || !sched_feat(LB_BIAS))
2328 return total;
2329
2330 return max(rq->cpu_load[type-1], total);
2331}
2332
2333static unsigned long power_of(int cpu)
2334{
2335 return cpu_rq(cpu)->cpu_power;
2336}
2337
2338static unsigned long cpu_avg_load_per_task(int cpu)
2339{
2340 struct rq *rq = cpu_rq(cpu);
2341 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
2342
2343 if (nr_running)
2344 return rq->load.weight / nr_running;
2345
2346 return 0;
2347}
2348
2349
2350static void task_waking_fair(struct task_struct *p)
2351{
2352 struct sched_entity *se = &p->se;
2353 struct cfs_rq *cfs_rq = cfs_rq_of(se);
2354 u64 min_vruntime;
2355
2356#ifndef CONFIG_64BIT
2357 u64 min_vruntime_copy;
2358
2359 do {
2360 min_vruntime_copy = cfs_rq->min_vruntime_copy;
2361 smp_rmb();
2362 min_vruntime = cfs_rq->min_vruntime;
2363 } while (min_vruntime != min_vruntime_copy);
2364#else
2365 min_vruntime = cfs_rq->min_vruntime;
2366#endif
2367
2368 se->vruntime -= min_vruntime;
2369}
2370
2371#ifdef CONFIG_FAIR_GROUP_SCHED
2372/*
2373 * effective_load() calculates the load change as seen from the root_task_group
2374 *
2375 * Adding load to a group doesn't make a group heavier, but can cause movement
2376 * of group shares between cpus. Assuming the shares were perfectly aligned one
2377 * can calculate the shift in shares.
2378 *
2379 * Calculate the effective load difference if @wl is added (subtracted) to @tg
2380 * on this @cpu and results in a total addition (subtraction) of @wg to the
2381 * total group weight.
2382 *
2383 * Given a runqueue weight distribution (rw_i) we can compute a shares
2384 * distribution (s_i) using:
2385 *
2386 * s_i = rw_i / \Sum rw_j (1)
2387 *
2388 * Suppose we have 4 CPUs and our @tg is a direct child of the root group and
2389 * has 7 equal weight tasks, distributed as below (rw_i), with the resulting
2390 * shares distribution (s_i):
2391 *
2392 * rw_i = { 2, 4, 1, 0 }
2393 * s_i = { 2/7, 4/7, 1/7, 0 }
2394 *
2395 * As per wake_affine() we're interested in the load of two CPUs (the CPU the
2396 * task used to run on and the CPU the waker is running on), we need to
2397 * compute the effect of waking a task on either CPU and, in case of a sync
2398 * wakeup, compute the effect of the current task going to sleep.
2399 *
2400 * So for a change of @wl to the local @cpu with an overall group weight change
2401 * of @wl we can compute the new shares distribution (s'_i) using:
2402 *
2403 * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2)
2404 *
2405 * Suppose we're interested in CPUs 0 and 1, and want to compute the load
2406 * differences in waking a task to CPU 0. The additional task changes the
2407 * weight and shares distributions like:
2408 *
2409 * rw'_i = { 3, 4, 1, 0 }
2410 * s'_i = { 3/8, 4/8, 1/8, 0 }
2411 *
2412 * We can then compute the difference in effective weight by using:
2413 *
2414 * dw_i = S * (s'_i - s_i) (3)
2415 *
2416 * Where 'S' is the group weight as seen by its parent.
2417 *
2418 * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7)
2419 * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 -
2420 * 4/7) times the weight of the group.
2421 */
2422static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
2423{
2424 struct sched_entity *se = tg->se[cpu];
2425
2426 if (!tg->parent) /* the trivial, non-cgroup case */
2427 return wl;
2428
2429 for_each_sched_entity(se) {
2430 long w, W;
2431
2432 tg = se->my_q->tg;
2433
2434 /*
2435 * W = @wg + \Sum rw_j
2436 */
2437 W = wg + calc_tg_weight(tg, se->my_q);
2438
2439 /*
2440 * w = rw_i + @wl
2441 */
2442 w = se->my_q->load.weight + wl;
2443
2444 /*
2445 * wl = S * s'_i; see (2)
2446 */
2447 if (W > 0 && w < W)
2448 wl = (w * tg->shares) / W;
2449 else
2450 wl = tg->shares;
2451
2452 /*
2453 * Per the above, wl is the new se->load.weight value; since
2454 * those are clipped to [MIN_SHARES, ...) do so now. See
2455 * calc_cfs_shares().
2456 */
2457 if (wl < MIN_SHARES)
2458 wl = MIN_SHARES;
2459
2460 /*
2461 * wl = dw_i = S * (s'_i - s_i); see (3)
2462 */
2463 wl -= se->load.weight;
2464
2465 /*
2466 * Recursively apply this logic to all parent groups to compute
2467 * the final effective load change on the root group. Since
2468 * only the @tg group gets extra weight, all parent groups can
2469 * only redistribute existing shares. @wl is the shift in shares
2470 * resulting from this level per the above.
2471 */
2472 wg = 0;
2473 }
2474
2475 return wl;
2476}
2477#else
2478
2479static inline unsigned long effective_load(struct task_group *tg, int cpu,
2480 unsigned long wl, unsigned long wg)
2481{
2482 return wl;
2483}
2484
2485#endif
2486
2487static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
2488{
2489 s64 this_load, load;
2490 int idx, this_cpu, prev_cpu;
2491 unsigned long tl_per_task;
2492 struct task_group *tg;
2493 unsigned long weight;
2494 int balanced;
2495
2496 idx = sd->wake_idx;
2497 this_cpu = smp_processor_id();
2498 prev_cpu = task_cpu(p);
2499 load = source_load(prev_cpu, idx);
2500 this_load = target_load(this_cpu, idx);
2501
2502 /*
2503 * If sync wakeup then subtract the (maximum possible)
2504 * effect of the currently running task from the load
2505 * of the current CPU:
2506 */
2507 if (sync) {
2508 tg = task_group(current);
2509 weight = current->se.load.weight;
2510
2511 this_load += effective_load(tg, this_cpu, -weight, -weight);
2512 load += effective_load(tg, prev_cpu, 0, -weight);
2513 }
2514
2515 tg = task_group(p);
2516 weight = p->se.load.weight;
2517
2518 /*
2519 * In low-load situations, where prev_cpu is idle and this_cpu is idle
2520 * due to the sync cause above having dropped this_load to 0, we'll
2521 * always have an imbalance, but there's really nothing you can do
2522 * about that, so that's good too.
2523 *
2524 * Otherwise check if either cpus are near enough in load to allow this
2525 * task to be woken on this_cpu.
2526 */
2527 if (this_load > 0) {
2528 s64 this_eff_load, prev_eff_load;
2529
2530 this_eff_load = 100;
2531 this_eff_load *= power_of(prev_cpu);
2532 this_eff_load *= this_load +
2533 effective_load(tg, this_cpu, weight, weight);
2534
2535 prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
2536 prev_eff_load *= power_of(this_cpu);
2537 prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
2538
2539 balanced = this_eff_load <= prev_eff_load;
2540 } else
2541 balanced = true;
2542
2543 /*
2544 * If the currently running task will sleep within
2545 * a reasonable amount of time then attract this newly
2546 * woken task:
2547 */
2548 if (sync && balanced)
2549 return 1;
2550
2551 schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
2552 tl_per_task = cpu_avg_load_per_task(this_cpu);
2553
2554 if (balanced ||
2555 (this_load <= load &&
2556 this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
2557 /*
2558 * This domain has SD_WAKE_AFFINE and
2559 * p is cache cold in this domain, and
2560 * there is no bad imbalance.
2561 */
2562 schedstat_inc(sd, ttwu_move_affine);
2563 schedstat_inc(p, se.statistics.nr_wakeups_affine);
2564
2565 return 1;
2566 }
2567 return 0;
2568}
2569
2570/*
2571 * find_idlest_group finds and returns the least busy CPU group within the
2572 * domain.
2573 */
2574static struct sched_group *
2575find_idlest_group(struct sched_domain *sd, struct task_struct *p,
2576 int this_cpu, int load_idx)
2577{
2578 struct sched_group *idlest = NULL, *group = sd->groups;
2579 unsigned long min_load = ULONG_MAX, this_load = 0;
2580 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2581
2582 do {
2583 unsigned long load, avg_load;
2584 int local_group;
2585 int i;
2586
2587 /* Skip over this group if it has no CPUs allowed */
2588 if (!cpumask_intersects(sched_group_cpus(group),
2589 tsk_cpus_allowed(p)))
2590 continue;
2591
2592 local_group = cpumask_test_cpu(this_cpu,
2593 sched_group_cpus(group));
2594
2595 /* Tally up the load of all CPUs in the group */
2596 avg_load = 0;
2597
2598 for_each_cpu(i, sched_group_cpus(group)) {
2599 /* Bias balancing toward cpus of our domain */
2600 if (local_group)
2601 load = source_load(i, load_idx);
2602 else
2603 load = target_load(i, load_idx);
2604
2605 avg_load += load;
2606 }
2607
2608 /* Adjust by relative CPU power of the group */
2609 avg_load = (avg_load * SCHED_POWER_SCALE) / group->sgp->power;
2610
2611 if (local_group) {
2612 this_load = avg_load;
2613 } else if (avg_load < min_load) {
2614 min_load = avg_load;
2615 idlest = group;
2616 }
2617 } while (group = group->next, group != sd->groups);
2618
2619 if (!idlest || 100*this_load < imbalance*min_load)
2620 return NULL;
2621 return idlest;
2622}
2623
2624/*
2625 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2626 */
2627static int
2628find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2629{
2630 unsigned long load, min_load = ULONG_MAX;
2631 int idlest = -1;
2632 int i;
2633
2634 /* Traverse only the allowed CPUs */
2635 for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
2636 load = weighted_cpuload(i);
2637
2638 if (load < min_load || (load == min_load && i == this_cpu)) {
2639 min_load = load;
2640 idlest = i;
2641 }
2642 }
2643
2644 return idlest;
2645}
2646
2647/**
2648 * highest_flag_domain - Return highest sched_domain containing flag.
2649 * @cpu: The cpu whose highest level of sched domain is to
2650 * be returned.
2651 * @flag: The flag to check for the highest sched_domain
2652 * for the given cpu.
2653 *
2654 * Returns the highest sched_domain of a cpu which contains the given flag.
2655 */
2656static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
2657{
2658 struct sched_domain *sd, *hsd = NULL;
2659
2660 for_each_domain(cpu, sd) {
2661 if (!(sd->flags & flag))
2662 break;
2663 hsd = sd;
2664 }
2665
2666 return hsd;
2667}
2668
2669/*
2670 * Try and locate an idle CPU in the sched_domain.
2671 */
2672static int select_idle_sibling(struct task_struct *p, int target)
2673{
2674 int cpu = smp_processor_id();
2675 int prev_cpu = task_cpu(p);
2676 struct sched_domain *sd;
2677 struct sched_group *sg;
2678 int i;
2679
2680 /*
2681 * If the task is going to be woken-up on this cpu and if it is
2682 * already idle, then it is the right target.
2683 */
2684 if (target == cpu && idle_cpu(cpu))
2685 return cpu;
2686
2687 /*
2688 * If the task is going to be woken-up on the cpu where it previously
2689 * ran and if it is currently idle, then it the right target.
2690 */
2691 if (target == prev_cpu && idle_cpu(prev_cpu))
2692 return prev_cpu;
2693
2694 /*
2695 * Otherwise, iterate the domains and find an elegible idle cpu.
2696 */
2697 rcu_read_lock();
2698
2699 sd = highest_flag_domain(target, SD_SHARE_PKG_RESOURCES);
2700 for_each_lower_domain(sd) {
2701 sg = sd->groups;
2702 do {
2703 if (!cpumask_intersects(sched_group_cpus(sg),
2704 tsk_cpus_allowed(p)))
2705 goto next;
2706
2707 for_each_cpu(i, sched_group_cpus(sg)) {
2708 if (!idle_cpu(i))
2709 goto next;
2710 }
2711
2712 target = cpumask_first_and(sched_group_cpus(sg),
2713 tsk_cpus_allowed(p));
2714 goto done;
2715next:
2716 sg = sg->next;
2717 } while (sg != sd->groups);
2718 }
2719done:
2720 rcu_read_unlock();
2721
2722 return target;
2723}
2724
2725/*
2726 * sched_balance_self: balance the current task (running on cpu) in domains
2727 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2728 * SD_BALANCE_EXEC.
2729 *
2730 * Balance, ie. select the least loaded group.
2731 *
2732 * Returns the target CPU number, or the same CPU if no balancing is needed.
2733 *
2734 * preempt must be disabled.
2735 */
2736static int
2737select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
2738{
2739 struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL;
2740 int cpu = smp_processor_id();
2741 int prev_cpu = task_cpu(p);
2742 int new_cpu = cpu;
2743 int want_affine = 0;
2744 int want_sd = 1;
2745 int sync = wake_flags & WF_SYNC;
2746
2747 if (p->rt.nr_cpus_allowed == 1)
2748 return prev_cpu;
2749
2750 if (sd_flag & SD_BALANCE_WAKE) {
2751 if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
2752 want_affine = 1;
2753 new_cpu = prev_cpu;
2754 }
2755
2756 rcu_read_lock();
2757 for_each_domain(cpu, tmp) {
2758 if (!(tmp->flags & SD_LOAD_BALANCE))
2759 continue;
2760
2761 /*
2762 * If power savings logic is enabled for a domain, see if we
2763 * are not overloaded, if so, don't balance wider.
2764 */
2765 if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) {
2766 unsigned long power = 0;
2767 unsigned long nr_running = 0;
2768 unsigned long capacity;
2769 int i;
2770
2771 for_each_cpu(i, sched_domain_span(tmp)) {
2772 power += power_of(i);
2773 nr_running += cpu_rq(i)->cfs.nr_running;
2774 }
2775
2776 capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
2777
2778 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2779 nr_running /= 2;
2780
2781 if (nr_running < capacity)
2782 want_sd = 0;
2783 }
2784
2785 /*
2786 * If both cpu and prev_cpu are part of this domain,
2787 * cpu is a valid SD_WAKE_AFFINE target.
2788 */
2789 if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
2790 cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
2791 affine_sd = tmp;
2792 want_affine = 0;
2793 }
2794
2795 if (!want_sd && !want_affine)
2796 break;
2797
2798 if (!(tmp->flags & sd_flag))
2799 continue;
2800
2801 if (want_sd)
2802 sd = tmp;
2803 }
2804
2805 if (affine_sd) {
2806 if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
2807 prev_cpu = cpu;
2808
2809 new_cpu = select_idle_sibling(p, prev_cpu);
2810 goto unlock;
2811 }
2812
2813 while (sd) {
2814 int load_idx = sd->forkexec_idx;
2815 struct sched_group *group;
2816 int weight;
2817
2818 if (!(sd->flags & sd_flag)) {
2819 sd = sd->child;
2820 continue;
2821 }
2822
2823 if (sd_flag & SD_BALANCE_WAKE)
2824 load_idx = sd->wake_idx;
2825
2826 group = find_idlest_group(sd, p, cpu, load_idx);
2827 if (!group) {
2828 sd = sd->child;
2829 continue;
2830 }
2831
2832 new_cpu = find_idlest_cpu(group, p, cpu);
2833 if (new_cpu == -1 || new_cpu == cpu) {
2834 /* Now try balancing at a lower domain level of cpu */
2835 sd = sd->child;
2836 continue;
2837 }
2838
2839 /* Now try balancing at a lower domain level of new_cpu */
2840 cpu = new_cpu;
2841 weight = sd->span_weight;
2842 sd = NULL;
2843 for_each_domain(cpu, tmp) {
2844 if (weight <= tmp->span_weight)
2845 break;
2846 if (tmp->flags & sd_flag)
2847 sd = tmp;
2848 }
2849 /* while loop will break here if sd == NULL */
2850 }
2851unlock:
2852 rcu_read_unlock();
2853
2854 return new_cpu;
2855}
2856#endif /* CONFIG_SMP */
2857
2858static unsigned long
2859wakeup_gran(struct sched_entity *curr, struct sched_entity *se)
2860{
2861 unsigned long gran = sysctl_sched_wakeup_granularity;
2862
2863 /*
2864 * Since its curr running now, convert the gran from real-time
2865 * to virtual-time in his units.
2866 *
2867 * By using 'se' instead of 'curr' we penalize light tasks, so
2868 * they get preempted easier. That is, if 'se' < 'curr' then
2869 * the resulting gran will be larger, therefore penalizing the
2870 * lighter, if otoh 'se' > 'curr' then the resulting gran will
2871 * be smaller, again penalizing the lighter task.
2872 *
2873 * This is especially important for buddies when the leftmost
2874 * task is higher priority than the buddy.
2875 */
2876 return calc_delta_fair(gran, se);
2877}
2878
2879/*
2880 * Should 'se' preempt 'curr'.
2881 *
2882 * |s1
2883 * |s2
2884 * |s3
2885 * g
2886 * |<--->|c
2887 *
2888 * w(c, s1) = -1
2889 * w(c, s2) = 0
2890 * w(c, s3) = 1
2891 *
2892 */
2893static int
2894wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
2895{
2896 s64 gran, vdiff = curr->vruntime - se->vruntime;
2897
2898 if (vdiff <= 0)
2899 return -1;
2900
2901 gran = wakeup_gran(curr, se);
2902 if (vdiff > gran)
2903 return 1;
2904
2905 return 0;
2906}
2907
2908static void set_last_buddy(struct sched_entity *se)
2909{
2910 if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
2911 return;
2912
2913 for_each_sched_entity(se)
2914 cfs_rq_of(se)->last = se;
2915}
2916
2917static void set_next_buddy(struct sched_entity *se)
2918{
2919 if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
2920 return;
2921
2922 for_each_sched_entity(se)
2923 cfs_rq_of(se)->next = se;
2924}
2925
2926static void set_skip_buddy(struct sched_entity *se)
2927{
2928 for_each_sched_entity(se)
2929 cfs_rq_of(se)->skip = se;
2930}
2931
2932/*
2933 * Preempt the current task with a newly woken task if needed:
2934 */
2935static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
2936{
2937 struct task_struct *curr = rq->curr;
2938 struct sched_entity *se = &curr->se, *pse = &p->se;
2939 struct cfs_rq *cfs_rq = task_cfs_rq(curr);
2940 int scale = cfs_rq->nr_running >= sched_nr_latency;
2941 int next_buddy_marked = 0;
2942
2943 if (unlikely(se == pse))
2944 return;
2945
2946 /*
2947 * This is possible from callers such as pull_task(), in which we
2948 * unconditionally check_prempt_curr() after an enqueue (which may have
2949 * lead to a throttle). This both saves work and prevents false
2950 * next-buddy nomination below.
2951 */
2952 if (unlikely(throttled_hierarchy(cfs_rq_of(pse))))
2953 return;
2954
2955 if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
2956 set_next_buddy(pse);
2957 next_buddy_marked = 1;
2958 }
2959
2960 /*
2961 * We can come here with TIF_NEED_RESCHED already set from new task
2962 * wake up path.
2963 *
2964 * Note: this also catches the edge-case of curr being in a throttled
2965 * group (e.g. via set_curr_task), since update_curr() (in the
2966 * enqueue of curr) will have resulted in resched being set. This
2967 * prevents us from potentially nominating it as a false LAST_BUDDY
2968 * below.
2969 */
2970 if (test_tsk_need_resched(curr))
2971 return;
2972
2973 /* Idle tasks are by definition preempted by non-idle tasks. */
2974 if (unlikely(curr->policy == SCHED_IDLE) &&
2975 likely(p->policy != SCHED_IDLE))
2976 goto preempt;
2977
2978 /*
2979 * Batch and idle tasks do not preempt non-idle tasks (their preemption
2980 * is driven by the tick):
2981 */
2982 if (unlikely(p->policy != SCHED_NORMAL))
2983 return;
2984
2985 find_matching_se(&se, &pse);
2986 update_curr(cfs_rq_of(se));
2987 BUG_ON(!pse);
2988 if (wakeup_preempt_entity(se, pse) == 1) {
2989 /*
2990 * Bias pick_next to pick the sched entity that is
2991 * triggering this preemption.
2992 */
2993 if (!next_buddy_marked)
2994 set_next_buddy(pse);
2995 goto preempt;
2996 }
2997
2998 return;
2999
3000preempt:
3001 resched_task(curr);
3002 /*
3003 * Only set the backward buddy when the current task is still
3004 * on the rq. This can happen when a wakeup gets interleaved
3005 * with schedule on the ->pre_schedule() or idle_balance()
3006 * point, either of which can * drop the rq lock.
3007 *
3008 * Also, during early boot the idle thread is in the fair class,
3009 * for obvious reasons its a bad idea to schedule back to it.
3010 */
3011 if (unlikely(!se->on_rq || curr == rq->idle))
3012 return;
3013
3014 if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se))
3015 set_last_buddy(se);
3016}
3017
3018static struct task_struct *pick_next_task_fair(struct rq *rq)
3019{
3020 struct task_struct *p;
3021 struct cfs_rq *cfs_rq = &rq->cfs;
3022 struct sched_entity *se;
3023
3024 if (!cfs_rq->nr_running)
3025 return NULL;
3026
3027 do {
3028 se = pick_next_entity(cfs_rq);
3029 set_next_entity(cfs_rq, se);
3030 cfs_rq = group_cfs_rq(se);
3031 } while (cfs_rq);
3032
3033 p = task_of(se);
3034 if (hrtick_enabled(rq))
3035 hrtick_start_fair(rq, p);
3036
3037 return p;
3038}
3039
3040/*
3041 * Account for a descheduled task:
3042 */
3043static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
3044{
3045 struct sched_entity *se = &prev->se;
3046 struct cfs_rq *cfs_rq;
3047
3048 for_each_sched_entity(se) {
3049 cfs_rq = cfs_rq_of(se);
3050 put_prev_entity(cfs_rq, se);
3051 }
3052}
3053
3054/*
3055 * sched_yield() is very simple
3056 *
3057 * The magic of dealing with the ->skip buddy is in pick_next_entity.
3058 */
3059static void yield_task_fair(struct rq *rq)
3060{
3061 struct task_struct *curr = rq->curr;
3062 struct cfs_rq *cfs_rq = task_cfs_rq(curr);
3063 struct sched_entity *se = &curr->se;
3064
3065 /*
3066 * Are we the only task in the tree?
3067 */
3068 if (unlikely(rq->nr_running == 1))
3069 return;
3070
3071 clear_buddies(cfs_rq, se);
3072
3073 if (curr->policy != SCHED_BATCH) {
3074 update_rq_clock(rq);
3075 /*
3076 * Update run-time statistics of the 'current'.
3077 */
3078 update_curr(cfs_rq);
3079 /*
3080 * Tell update_rq_clock() that we've just updated,
3081 * so we don't do microscopic update in schedule()
3082 * and double the fastpath cost.
3083 */
3084 rq->skip_clock_update = 1;
3085 }
3086
3087 set_skip_buddy(se);
3088}
3089
3090static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt)
3091{
3092 struct sched_entity *se = &p->se;
3093
3094 /* throttled hierarchies are not runnable */
3095 if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se)))
3096 return false;
3097
3098 /* Tell the scheduler that we'd really like pse to run next. */
3099 set_next_buddy(se);
3100
3101 yield_task_fair(rq);
3102
3103 return true;
3104}
3105
3106#ifdef CONFIG_SMP
3107/**************************************************
3108 * Fair scheduling class load-balancing methods:
3109 */
3110
3111/*
3112 * pull_task - move a task from a remote runqueue to the local runqueue.
3113 * Both runqueues must be locked.
3114 */
3115static void pull_task(struct rq *src_rq, struct task_struct *p,
3116 struct rq *this_rq, int this_cpu)
3117{
3118 deactivate_task(src_rq, p, 0);
3119 set_task_cpu(p, this_cpu);
3120 activate_task(this_rq, p, 0);
3121 check_preempt_curr(this_rq, p, 0);
3122}
3123
3124/*
3125 * Is this task likely cache-hot:
3126 */
3127static int
3128task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
3129{
3130 s64 delta;
3131
3132 if (p->sched_class != &fair_sched_class)
3133 return 0;
3134
3135 if (unlikely(p->policy == SCHED_IDLE))
3136 return 0;
3137
3138 /*
3139 * Buddy candidates are cache hot:
3140 */
3141 if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
3142 (&p->se == cfs_rq_of(&p->se)->next ||
3143 &p->se == cfs_rq_of(&p->se)->last))
3144 return 1;
3145
3146 if (sysctl_sched_migration_cost == -1)
3147 return 1;
3148 if (sysctl_sched_migration_cost == 0)
3149 return 0;
3150
3151 delta = now - p->se.exec_start;
3152
3153 return delta < (s64)sysctl_sched_migration_cost;
3154}
3155
3156/*
3157 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3158 */
3159static
3160int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
3161 struct sched_domain *sd, enum cpu_idle_type idle,
3162 int *all_pinned)
3163{
3164 int tsk_cache_hot = 0;
3165 /*
3166 * We do not migrate tasks that are:
3167 * 1) running (obviously), or
3168 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3169 * 3) are cache-hot on their current CPU.
3170 */
3171 if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) {
3172 schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
3173 return 0;
3174 }
3175 *all_pinned = 0;
3176
3177 if (task_running(rq, p)) {
3178 schedstat_inc(p, se.statistics.nr_failed_migrations_running);
3179 return 0;
3180 }
3181
3182 /*
3183 * Aggressive migration if:
3184 * 1) task is cache cold, or
3185 * 2) too many balance attempts have failed.
3186 */
3187
3188 tsk_cache_hot = task_hot(p, rq->clock_task, sd);
3189 if (!tsk_cache_hot ||
3190 sd->nr_balance_failed > sd->cache_nice_tries) {
3191#ifdef CONFIG_SCHEDSTATS
3192 if (tsk_cache_hot) {
3193 schedstat_inc(sd, lb_hot_gained[idle]);
3194 schedstat_inc(p, se.statistics.nr_forced_migrations);
3195 }
3196#endif
3197 return 1;
3198 }
3199
3200 if (tsk_cache_hot) {
3201 schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
3202 return 0;
3203 }
3204 return 1;
3205}
3206
3207/*
3208 * move_one_task tries to move exactly one task from busiest to this_rq, as
3209 * part of active balancing operations within "domain".
3210 * Returns 1 if successful and 0 otherwise.
3211 *
3212 * Called with both runqueues locked.
3213 */
3214static int
3215move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3216 struct sched_domain *sd, enum cpu_idle_type idle)
3217{
3218 struct task_struct *p, *n;
3219 struct cfs_rq *cfs_rq;
3220 int pinned = 0;
3221
3222 for_each_leaf_cfs_rq(busiest, cfs_rq) {
3223 list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) {
3224 if (throttled_lb_pair(task_group(p),
3225 busiest->cpu, this_cpu))
3226 break;
3227
3228 if (!can_migrate_task(p, busiest, this_cpu,
3229 sd, idle, &pinned))
3230 continue;
3231
3232 pull_task(busiest, p, this_rq, this_cpu);
3233 /*
3234 * Right now, this is only the second place pull_task()
3235 * is called, so we can safely collect pull_task()
3236 * stats here rather than inside pull_task().
3237 */
3238 schedstat_inc(sd, lb_gained[idle]);
3239 return 1;
3240 }
3241 }
3242
3243 return 0;
3244}
3245
3246static unsigned long
3247balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3248 unsigned long max_load_move, struct sched_domain *sd,
3249 enum cpu_idle_type idle, int *all_pinned,
3250 struct cfs_rq *busiest_cfs_rq)
3251{
3252 int loops = 0, pulled = 0;
3253 long rem_load_move = max_load_move;
3254 struct task_struct *p, *n;
3255
3256 if (max_load_move == 0)
3257 goto out;
3258
3259 list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) {
3260 if (loops++ > sysctl_sched_nr_migrate)
3261 break;
3262
3263 if ((p->se.load.weight >> 1) > rem_load_move ||
3264 !can_migrate_task(p, busiest, this_cpu, sd, idle,
3265 all_pinned))
3266 continue;
3267
3268 pull_task(busiest, p, this_rq, this_cpu);
3269 pulled++;
3270 rem_load_move -= p->se.load.weight;
3271
3272#ifdef CONFIG_PREEMPT
3273 /*
3274 * NEWIDLE balancing is a source of latency, so preemptible
3275 * kernels will stop after the first task is pulled to minimize
3276 * the critical section.
3277 */
3278 if (idle == CPU_NEWLY_IDLE)
3279 break;
3280#endif
3281
3282 /*
3283 * We only want to steal up to the prescribed amount of
3284 * weighted load.
3285 */
3286 if (rem_load_move <= 0)
3287 break;
3288 }
3289out:
3290 /*
3291 * Right now, this is one of only two places pull_task() is called,
3292 * so we can safely collect pull_task() stats here rather than
3293 * inside pull_task().
3294 */
3295 schedstat_add(sd, lb_gained[idle], pulled);
3296
3297 return max_load_move - rem_load_move;
3298}
3299
3300#ifdef CONFIG_FAIR_GROUP_SCHED
3301/*
3302 * update tg->load_weight by folding this cpu's load_avg
3303 */
3304static int update_shares_cpu(struct task_group *tg, int cpu)
3305{
3306 struct cfs_rq *cfs_rq;
3307 unsigned long flags;
3308 struct rq *rq;
3309
3310 if (!tg->se[cpu])
3311 return 0;
3312
3313 rq = cpu_rq(cpu);
3314 cfs_rq = tg->cfs_rq[cpu];
3315
3316 raw_spin_lock_irqsave(&rq->lock, flags);
3317
3318 update_rq_clock(rq);
3319 update_cfs_load(cfs_rq, 1);
3320
3321 /*
3322 * We need to update shares after updating tg->load_weight in
3323 * order to adjust the weight of groups with long running tasks.
3324 */
3325 update_cfs_shares(cfs_rq);
3326
3327 raw_spin_unlock_irqrestore(&rq->lock, flags);
3328
3329 return 0;
3330}
3331
3332static void update_shares(int cpu)
3333{
3334 struct cfs_rq *cfs_rq;
3335 struct rq *rq = cpu_rq(cpu);
3336
3337 rcu_read_lock();
3338 /*
3339 * Iterates the task_group tree in a bottom up fashion, see
3340 * list_add_leaf_cfs_rq() for details.
3341 */
3342 for_each_leaf_cfs_rq(rq, cfs_rq) {
3343 /* throttled entities do not contribute to load */
3344 if (throttled_hierarchy(cfs_rq))
3345 continue;
3346
3347 update_shares_cpu(cfs_rq->tg, cpu);
3348 }
3349 rcu_read_unlock();
3350}
3351
3352/*
3353 * Compute the cpu's hierarchical load factor for each task group.
3354 * This needs to be done in a top-down fashion because the load of a child
3355 * group is a fraction of its parents load.
3356 */
3357static int tg_load_down(struct task_group *tg, void *data)
3358{
3359 unsigned long load;
3360 long cpu = (long)data;
3361
3362 if (!tg->parent) {
3363 load = cpu_rq(cpu)->load.weight;
3364 } else {
3365 load = tg->parent->cfs_rq[cpu]->h_load;
3366 load *= tg->se[cpu]->load.weight;
3367 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
3368 }
3369
3370 tg->cfs_rq[cpu]->h_load = load;
3371
3372 return 0;
3373}
3374
3375static void update_h_load(long cpu)
3376{
3377 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
3378}
3379
3380static unsigned long
3381load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
3382 unsigned long max_load_move,
3383 struct sched_domain *sd, enum cpu_idle_type idle,
3384 int *all_pinned)
3385{
3386 long rem_load_move = max_load_move;
3387 struct cfs_rq *busiest_cfs_rq;
3388
3389 rcu_read_lock();
3390 update_h_load(cpu_of(busiest));
3391
3392 for_each_leaf_cfs_rq(busiest, busiest_cfs_rq) {
3393 unsigned long busiest_h_load = busiest_cfs_rq->h_load;
3394 unsigned long busiest_weight = busiest_cfs_rq->load.weight;
3395 u64 rem_load, moved_load;
3396
3397 /*
3398 * empty group or part of a throttled hierarchy
3399 */
3400 if (!busiest_cfs_rq->task_weight ||
3401 throttled_lb_pair(busiest_cfs_rq->tg, cpu_of(busiest), this_cpu))
3402 continue;
3403
3404 rem_load = (u64)rem_load_move * busiest_weight;
3405 rem_load = div_u64(rem_load, busiest_h_load + 1);
3406
3407 moved_load = balance_tasks(this_rq, this_cpu, busiest,
3408 rem_load, sd, idle, all_pinned,
3409 busiest_cfs_rq);
3410
3411 if (!moved_load)
3412 continue;
3413
3414 moved_load *= busiest_h_load;
3415 moved_load = div_u64(moved_load, busiest_weight + 1);
3416
3417 rem_load_move -= moved_load;
3418 if (rem_load_move < 0)
3419 break;
3420 }
3421 rcu_read_unlock();
3422
3423 return max_load_move - rem_load_move;
3424}
3425#else
3426static inline void update_shares(int cpu)
3427{
3428}
3429
3430static unsigned long
3431load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
3432 unsigned long max_load_move,
3433 struct sched_domain *sd, enum cpu_idle_type idle,
3434 int *all_pinned)
3435{
3436 return balance_tasks(this_rq, this_cpu, busiest,
3437 max_load_move, sd, idle, all_pinned,
3438 &busiest->cfs);
3439}
3440#endif
3441
3442/*
3443 * move_tasks tries to move up to max_load_move weighted load from busiest to
3444 * this_rq, as part of a balancing operation within domain "sd".
3445 * Returns 1 if successful and 0 otherwise.
3446 *
3447 * Called with both runqueues locked.
3448 */
3449static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3450 unsigned long max_load_move,
3451 struct sched_domain *sd, enum cpu_idle_type idle,
3452 int *all_pinned)
3453{
3454 unsigned long total_load_moved = 0, load_moved;
3455
3456 do {
3457 load_moved = load_balance_fair(this_rq, this_cpu, busiest,
3458 max_load_move - total_load_moved,
3459 sd, idle, all_pinned);
3460
3461 total_load_moved += load_moved;
3462
3463#ifdef CONFIG_PREEMPT
3464 /*
3465 * NEWIDLE balancing is a source of latency, so preemptible
3466 * kernels will stop after the first task is pulled to minimize
3467 * the critical section.
3468 */
3469 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3470 break;
3471
3472 if (raw_spin_is_contended(&this_rq->lock) ||
3473 raw_spin_is_contended(&busiest->lock))
3474 break;
3475#endif
3476 } while (load_moved && max_load_move > total_load_moved);
3477
3478 return total_load_moved > 0;
3479}
3480
3481/********** Helpers for find_busiest_group ************************/
3482/*
3483 * sd_lb_stats - Structure to store the statistics of a sched_domain
3484 * during load balancing.
3485 */
3486struct sd_lb_stats {
3487 struct sched_group *busiest; /* Busiest group in this sd */
3488 struct sched_group *this; /* Local group in this sd */
3489 unsigned long total_load; /* Total load of all groups in sd */
3490 unsigned long total_pwr; /* Total power of all groups in sd */
3491 unsigned long avg_load; /* Average load across all groups in sd */
3492
3493 /** Statistics of this group */
3494 unsigned long this_load;
3495 unsigned long this_load_per_task;
3496 unsigned long this_nr_running;
3497 unsigned long this_has_capacity;
3498 unsigned int this_idle_cpus;
3499
3500 /* Statistics of the busiest group */
3501 unsigned int busiest_idle_cpus;
3502 unsigned long max_load;
3503 unsigned long busiest_load_per_task;
3504 unsigned long busiest_nr_running;
3505 unsigned long busiest_group_capacity;
3506 unsigned long busiest_has_capacity;
3507 unsigned int busiest_group_weight;
3508
3509 int group_imb; /* Is there imbalance in this sd */
3510#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3511 int power_savings_balance; /* Is powersave balance needed for this sd */
3512 struct sched_group *group_min; /* Least loaded group in sd */
3513 struct sched_group *group_leader; /* Group which relieves group_min */
3514 unsigned long min_load_per_task; /* load_per_task in group_min */
3515 unsigned long leader_nr_running; /* Nr running of group_leader */
3516 unsigned long min_nr_running; /* Nr running of group_min */
3517#endif
3518};
3519
3520/*
3521 * sg_lb_stats - stats of a sched_group required for load_balancing
3522 */
3523struct sg_lb_stats {
3524 unsigned long avg_load; /*Avg load across the CPUs of the group */
3525 unsigned long group_load; /* Total load over the CPUs of the group */
3526 unsigned long sum_nr_running; /* Nr tasks running in the group */
3527 unsigned long sum_weighted_load; /* Weighted load of group's tasks */
3528 unsigned long group_capacity;
3529 unsigned long idle_cpus;
3530 unsigned long group_weight;
3531 int group_imb; /* Is there an imbalance in the group ? */
3532 int group_has_capacity; /* Is there extra capacity in the group? */
3533};
3534
3535/**
3536 * get_sd_load_idx - Obtain the load index for a given sched domain.
3537 * @sd: The sched_domain whose load_idx is to be obtained.
3538 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3539 */
3540static inline int get_sd_load_idx(struct sched_domain *sd,
3541 enum cpu_idle_type idle)
3542{
3543 int load_idx;
3544
3545 switch (idle) {
3546 case CPU_NOT_IDLE:
3547 load_idx = sd->busy_idx;
3548 break;
3549
3550 case CPU_NEWLY_IDLE:
3551 load_idx = sd->newidle_idx;
3552 break;
3553 default:
3554 load_idx = sd->idle_idx;
3555 break;
3556 }
3557
3558 return load_idx;
3559}
3560
3561
3562#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3563/**
3564 * init_sd_power_savings_stats - Initialize power savings statistics for
3565 * the given sched_domain, during load balancing.
3566 *
3567 * @sd: Sched domain whose power-savings statistics are to be initialized.
3568 * @sds: Variable containing the statistics for sd.
3569 * @idle: Idle status of the CPU at which we're performing load-balancing.
3570 */
3571static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3572 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3573{
3574 /*
3575 * Busy processors will not participate in power savings
3576 * balance.
3577 */
3578 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3579 sds->power_savings_balance = 0;
3580 else {
3581 sds->power_savings_balance = 1;
3582 sds->min_nr_running = ULONG_MAX;
3583 sds->leader_nr_running = 0;
3584 }
3585}
3586
3587/**
3588 * update_sd_power_savings_stats - Update the power saving stats for a
3589 * sched_domain while performing load balancing.
3590 *
3591 * @group: sched_group belonging to the sched_domain under consideration.
3592 * @sds: Variable containing the statistics of the sched_domain
3593 * @local_group: Does group contain the CPU for which we're performing
3594 * load balancing ?
3595 * @sgs: Variable containing the statistics of the group.
3596 */
3597static inline void update_sd_power_savings_stats(struct sched_group *group,
3598 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3599{
3600
3601 if (!sds->power_savings_balance)
3602 return;
3603
3604 /*
3605 * If the local group is idle or completely loaded
3606 * no need to do power savings balance at this domain
3607 */
3608 if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
3609 !sds->this_nr_running))
3610 sds->power_savings_balance = 0;
3611
3612 /*
3613 * If a group is already running at full capacity or idle,
3614 * don't include that group in power savings calculations
3615 */
3616 if (!sds->power_savings_balance ||
3617 sgs->sum_nr_running >= sgs->group_capacity ||
3618 !sgs->sum_nr_running)
3619 return;
3620
3621 /*
3622 * Calculate the group which has the least non-idle load.
3623 * This is the group from where we need to pick up the load
3624 * for saving power
3625 */
3626 if ((sgs->sum_nr_running < sds->min_nr_running) ||
3627 (sgs->sum_nr_running == sds->min_nr_running &&
3628 group_first_cpu(group) > group_first_cpu(sds->group_min))) {
3629 sds->group_min = group;
3630 sds->min_nr_running = sgs->sum_nr_running;
3631 sds->min_load_per_task = sgs->sum_weighted_load /
3632 sgs->sum_nr_running;
3633 }
3634
3635 /*
3636 * Calculate the group which is almost near its
3637 * capacity but still has some space to pick up some load
3638 * from other group and save more power
3639 */
3640 if (sgs->sum_nr_running + 1 > sgs->group_capacity)
3641 return;
3642
3643 if (sgs->sum_nr_running > sds->leader_nr_running ||
3644 (sgs->sum_nr_running == sds->leader_nr_running &&
3645 group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
3646 sds->group_leader = group;
3647 sds->leader_nr_running = sgs->sum_nr_running;
3648 }
3649}
3650
3651/**
3652 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3653 * @sds: Variable containing the statistics of the sched_domain
3654 * under consideration.
3655 * @this_cpu: Cpu at which we're currently performing load-balancing.
3656 * @imbalance: Variable to store the imbalance.
3657 *
3658 * Description:
3659 * Check if we have potential to perform some power-savings balance.
3660 * If yes, set the busiest group to be the least loaded group in the
3661 * sched_domain, so that it's CPUs can be put to idle.
3662 *
3663 * Returns 1 if there is potential to perform power-savings balance.
3664 * Else returns 0.
3665 */
3666static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3667 int this_cpu, unsigned long *imbalance)
3668{
3669 if (!sds->power_savings_balance)
3670 return 0;
3671
3672 if (sds->this != sds->group_leader ||
3673 sds->group_leader == sds->group_min)
3674 return 0;
3675
3676 *imbalance = sds->min_load_per_task;
3677 sds->busiest = sds->group_min;
3678
3679 return 1;
3680
3681}
3682#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3683static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3684 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3685{
3686 return;
3687}
3688
3689static inline void update_sd_power_savings_stats(struct sched_group *group,
3690 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3691{
3692 return;
3693}
3694
3695static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3696 int this_cpu, unsigned long *imbalance)
3697{
3698 return 0;
3699}
3700#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3701
3702
3703unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
3704{
3705 return SCHED_POWER_SCALE;
3706}
3707
3708unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
3709{
3710 return default_scale_freq_power(sd, cpu);
3711}
3712
3713unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
3714{
3715 unsigned long weight = sd->span_weight;
3716 unsigned long smt_gain = sd->smt_gain;
3717
3718 smt_gain /= weight;
3719
3720 return smt_gain;
3721}
3722
3723unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
3724{
3725 return default_scale_smt_power(sd, cpu);
3726}
3727
3728unsigned long scale_rt_power(int cpu)
3729{
3730 struct rq *rq = cpu_rq(cpu);
3731 u64 total, available;
3732
3733 total = sched_avg_period() + (rq->clock - rq->age_stamp);
3734
3735 if (unlikely(total < rq->rt_avg)) {
3736 /* Ensures that power won't end up being negative */
3737 available = 0;
3738 } else {
3739 available = total - rq->rt_avg;
3740 }
3741
3742 if (unlikely((s64)total < SCHED_POWER_SCALE))
3743 total = SCHED_POWER_SCALE;
3744
3745 total >>= SCHED_POWER_SHIFT;
3746
3747 return div_u64(available, total);
3748}
3749
3750static void update_cpu_power(struct sched_domain *sd, int cpu)
3751{
3752 unsigned long weight = sd->span_weight;
3753 unsigned long power = SCHED_POWER_SCALE;
3754 struct sched_group *sdg = sd->groups;
3755
3756 if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
3757 if (sched_feat(ARCH_POWER))
3758 power *= arch_scale_smt_power(sd, cpu);
3759 else
3760 power *= default_scale_smt_power(sd, cpu);
3761
3762 power >>= SCHED_POWER_SHIFT;
3763 }
3764
3765 sdg->sgp->power_orig = power;
3766
3767 if (sched_feat(ARCH_POWER))
3768 power *= arch_scale_freq_power(sd, cpu);
3769 else
3770 power *= default_scale_freq_power(sd, cpu);
3771
3772 power >>= SCHED_POWER_SHIFT;
3773
3774 power *= scale_rt_power(cpu);
3775 power >>= SCHED_POWER_SHIFT;
3776
3777 if (!power)
3778 power = 1;
3779
3780 cpu_rq(cpu)->cpu_power = power;
3781 sdg->sgp->power = power;
3782}
3783
3784void update_group_power(struct sched_domain *sd, int cpu)
3785{
3786 struct sched_domain *child = sd->child;
3787 struct sched_group *group, *sdg = sd->groups;
3788 unsigned long power;
3789
3790 if (!child) {
3791 update_cpu_power(sd, cpu);
3792 return;
3793 }
3794
3795 power = 0;
3796
3797 group = child->groups;
3798 do {
3799 power += group->sgp->power;
3800 group = group->next;
3801 } while (group != child->groups);
3802
3803 sdg->sgp->power = power;
3804}
3805
3806/*
3807 * Try and fix up capacity for tiny siblings, this is needed when
3808 * things like SD_ASYM_PACKING need f_b_g to select another sibling
3809 * which on its own isn't powerful enough.
3810 *
3811 * See update_sd_pick_busiest() and check_asym_packing().
3812 */
3813static inline int
3814fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
3815{
3816 /*
3817 * Only siblings can have significantly less than SCHED_POWER_SCALE
3818 */
3819 if (!(sd->flags & SD_SHARE_CPUPOWER))
3820 return 0;
3821
3822 /*
3823 * If ~90% of the cpu_power is still there, we're good.
3824 */
3825 if (group->sgp->power * 32 > group->sgp->power_orig * 29)
3826 return 1;
3827
3828 return 0;
3829}
3830
3831/**
3832 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3833 * @sd: The sched_domain whose statistics are to be updated.
3834 * @group: sched_group whose statistics are to be updated.
3835 * @this_cpu: Cpu for which load balance is currently performed.
3836 * @idle: Idle status of this_cpu
3837 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3838 * @local_group: Does group contain this_cpu.
3839 * @cpus: Set of cpus considered for load balancing.
3840 * @balance: Should we balance.
3841 * @sgs: variable to hold the statistics for this group.
3842 */
3843static inline void update_sg_lb_stats(struct sched_domain *sd,
3844 struct sched_group *group, int this_cpu,
3845 enum cpu_idle_type idle, int load_idx,
3846 int local_group, const struct cpumask *cpus,
3847 int *balance, struct sg_lb_stats *sgs)
3848{
3849 unsigned long load, max_cpu_load, min_cpu_load, max_nr_running;
3850 int i;
3851 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3852 unsigned long avg_load_per_task = 0;
3853
3854 if (local_group)
3855 balance_cpu = group_first_cpu(group);
3856
3857 /* Tally up the load of all CPUs in the group */
3858 max_cpu_load = 0;
3859 min_cpu_load = ~0UL;
3860 max_nr_running = 0;
3861
3862 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3863 struct rq *rq = cpu_rq(i);
3864
3865 /* Bias balancing toward cpus of our domain */
3866 if (local_group) {
3867 if (idle_cpu(i) && !first_idle_cpu) {
3868 first_idle_cpu = 1;
3869 balance_cpu = i;
3870 }
3871
3872 load = target_load(i, load_idx);
3873 } else {
3874 load = source_load(i, load_idx);
3875 if (load > max_cpu_load) {
3876 max_cpu_load = load;
3877 max_nr_running = rq->nr_running;
3878 }
3879 if (min_cpu_load > load)
3880 min_cpu_load = load;
3881 }
3882
3883 sgs->group_load += load;
3884 sgs->sum_nr_running += rq->nr_running;
3885 sgs->sum_weighted_load += weighted_cpuload(i);
3886 if (idle_cpu(i))
3887 sgs->idle_cpus++;
3888 }
3889
3890 /*
3891 * First idle cpu or the first cpu(busiest) in this sched group
3892 * is eligible for doing load balancing at this and above
3893 * domains. In the newly idle case, we will allow all the cpu's
3894 * to do the newly idle load balance.
3895 */
3896 if (idle != CPU_NEWLY_IDLE && local_group) {
3897 if (balance_cpu != this_cpu) {
3898 *balance = 0;
3899 return;
3900 }
3901 update_group_power(sd, this_cpu);
3902 }
3903
3904 /* Adjust by relative CPU power of the group */
3905 sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->sgp->power;
3906
3907 /*
3908 * Consider the group unbalanced when the imbalance is larger
3909 * than the average weight of a task.
3910 *
3911 * APZ: with cgroup the avg task weight can vary wildly and
3912 * might not be a suitable number - should we keep a
3913 * normalized nr_running number somewhere that negates
3914 * the hierarchy?
3915 */
3916 if (sgs->sum_nr_running)
3917 avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
3918
3919 if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
3920 sgs->group_imb = 1;
3921
3922 sgs->group_capacity = DIV_ROUND_CLOSEST(group->sgp->power,
3923 SCHED_POWER_SCALE);
3924 if (!sgs->group_capacity)
3925 sgs->group_capacity = fix_small_capacity(sd, group);
3926 sgs->group_weight = group->group_weight;
3927
3928 if (sgs->group_capacity > sgs->sum_nr_running)
3929 sgs->group_has_capacity = 1;
3930}
3931
3932/**
3933 * update_sd_pick_busiest - return 1 on busiest group
3934 * @sd: sched_domain whose statistics are to be checked
3935 * @sds: sched_domain statistics
3936 * @sg: sched_group candidate to be checked for being the busiest
3937 * @sgs: sched_group statistics
3938 * @this_cpu: the current cpu
3939 *
3940 * Determine if @sg is a busier group than the previously selected
3941 * busiest group.
3942 */
3943static bool update_sd_pick_busiest(struct sched_domain *sd,
3944 struct sd_lb_stats *sds,
3945 struct sched_group *sg,
3946 struct sg_lb_stats *sgs,
3947 int this_cpu)
3948{
3949 if (sgs->avg_load <= sds->max_load)
3950 return false;
3951
3952 if (sgs->sum_nr_running > sgs->group_capacity)
3953 return true;
3954
3955 if (sgs->group_imb)
3956 return true;
3957
3958 /*
3959 * ASYM_PACKING needs to move all the work to the lowest
3960 * numbered CPUs in the group, therefore mark all groups
3961 * higher than ourself as busy.
3962 */
3963 if ((sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running &&
3964 this_cpu < group_first_cpu(sg)) {
3965 if (!sds->busiest)
3966 return true;
3967
3968 if (group_first_cpu(sds->busiest) > group_first_cpu(sg))
3969 return true;
3970 }
3971
3972 return false;
3973}
3974
3975/**
3976 * update_sd_lb_stats - Update sched_domain's statistics for load balancing.
3977 * @sd: sched_domain whose statistics are to be updated.
3978 * @this_cpu: Cpu for which load balance is currently performed.
3979 * @idle: Idle status of this_cpu
3980 * @cpus: Set of cpus considered for load balancing.
3981 * @balance: Should we balance.
3982 * @sds: variable to hold the statistics for this sched_domain.
3983 */
3984static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
3985 enum cpu_idle_type idle, const struct cpumask *cpus,
3986 int *balance, struct sd_lb_stats *sds)
3987{
3988 struct sched_domain *child = sd->child;
3989 struct sched_group *sg = sd->groups;
3990 struct sg_lb_stats sgs;
3991 int load_idx, prefer_sibling = 0;
3992
3993 if (child && child->flags & SD_PREFER_SIBLING)
3994 prefer_sibling = 1;
3995
3996 init_sd_power_savings_stats(sd, sds, idle);
3997 load_idx = get_sd_load_idx(sd, idle);
3998
3999 do {
4000 int local_group;
4001
4002 local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg));
4003 memset(&sgs, 0, sizeof(sgs));
4004 update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx,
4005 local_group, cpus, balance, &sgs);
4006
4007 if (local_group && !(*balance))
4008 return;
4009
4010 sds->total_load += sgs.group_load;
4011 sds->total_pwr += sg->sgp->power;
4012
4013 /*
4014 * In case the child domain prefers tasks go to siblings
4015 * first, lower the sg capacity to one so that we'll try
4016 * and move all the excess tasks away. We lower the capacity
4017 * of a group only if the local group has the capacity to fit
4018 * these excess tasks, i.e. nr_running < group_capacity. The
4019 * extra check prevents the case where you always pull from the
4020 * heaviest group when it is already under-utilized (possible
4021 * with a large weight task outweighs the tasks on the system).
4022 */
4023 if (prefer_sibling && !local_group && sds->this_has_capacity)
4024 sgs.group_capacity = min(sgs.group_capacity, 1UL);
4025
4026 if (local_group) {
4027 sds->this_load = sgs.avg_load;
4028 sds->this = sg;
4029 sds->this_nr_running = sgs.sum_nr_running;
4030 sds->this_load_per_task = sgs.sum_weighted_load;
4031 sds->this_has_capacity = sgs.group_has_capacity;
4032 sds->this_idle_cpus = sgs.idle_cpus;
4033 } else if (update_sd_pick_busiest(sd, sds, sg, &sgs, this_cpu)) {
4034 sds->max_load = sgs.avg_load;
4035 sds->busiest = sg;
4036 sds->busiest_nr_running = sgs.sum_nr_running;
4037 sds->busiest_idle_cpus = sgs.idle_cpus;
4038 sds->busiest_group_capacity = sgs.group_capacity;
4039 sds->busiest_load_per_task = sgs.sum_weighted_load;
4040 sds->busiest_has_capacity = sgs.group_has_capacity;
4041 sds->busiest_group_weight = sgs.group_weight;
4042 sds->group_imb = sgs.group_imb;
4043 }
4044
4045 update_sd_power_savings_stats(sg, sds, local_group, &sgs);
4046 sg = sg->next;
4047 } while (sg != sd->groups);
4048}
4049
4050/**
4051 * check_asym_packing - Check to see if the group is packed into the
4052 * sched doman.
4053 *
4054 * This is primarily intended to used at the sibling level. Some
4055 * cores like POWER7 prefer to use lower numbered SMT threads. In the
4056 * case of POWER7, it can move to lower SMT modes only when higher
4057 * threads are idle. When in lower SMT modes, the threads will
4058 * perform better since they share less core resources. Hence when we
4059 * have idle threads, we want them to be the higher ones.
4060 *
4061 * This packing function is run on idle threads. It checks to see if
4062 * the busiest CPU in this domain (core in the P7 case) has a higher
4063 * CPU number than the packing function is being run on. Here we are
4064 * assuming lower CPU number will be equivalent to lower a SMT thread
4065 * number.
4066 *
4067 * Returns 1 when packing is required and a task should be moved to
4068 * this CPU. The amount of the imbalance is returned in *imbalance.
4069 *
4070 * @sd: The sched_domain whose packing is to be checked.
4071 * @sds: Statistics of the sched_domain which is to be packed
4072 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
4073 * @imbalance: returns amount of imbalanced due to packing.
4074 */
4075static int check_asym_packing(struct sched_domain *sd,
4076 struct sd_lb_stats *sds,
4077 int this_cpu, unsigned long *imbalance)
4078{
4079 int busiest_cpu;
4080
4081 if (!(sd->flags & SD_ASYM_PACKING))
4082 return 0;
4083
4084 if (!sds->busiest)
4085 return 0;
4086
4087 busiest_cpu = group_first_cpu(sds->busiest);
4088 if (this_cpu > busiest_cpu)
4089 return 0;
4090
4091 *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->sgp->power,
4092 SCHED_POWER_SCALE);
4093 return 1;
4094}
4095
4096/**
4097 * fix_small_imbalance - Calculate the minor imbalance that exists
4098 * amongst the groups of a sched_domain, during
4099 * load balancing.
4100 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
4101 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
4102 * @imbalance: Variable to store the imbalance.
4103 */
4104static inline void fix_small_imbalance(struct sd_lb_stats *sds,
4105 int this_cpu, unsigned long *imbalance)
4106{
4107 unsigned long tmp, pwr_now = 0, pwr_move = 0;
4108 unsigned int imbn = 2;
4109 unsigned long scaled_busy_load_per_task;
4110
4111 if (sds->this_nr_running) {
4112 sds->this_load_per_task /= sds->this_nr_running;
4113 if (sds->busiest_load_per_task >
4114 sds->this_load_per_task)
4115 imbn = 1;
4116 } else
4117 sds->this_load_per_task =
4118 cpu_avg_load_per_task(this_cpu);
4119
4120 scaled_busy_load_per_task = sds->busiest_load_per_task
4121 * SCHED_POWER_SCALE;
4122 scaled_busy_load_per_task /= sds->busiest->sgp->power;
4123
4124 if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
4125 (scaled_busy_load_per_task * imbn)) {
4126 *imbalance = sds->busiest_load_per_task;
4127 return;
4128 }
4129
4130 /*
4131 * OK, we don't have enough imbalance to justify moving tasks,
4132 * however we may be able to increase total CPU power used by
4133 * moving them.
4134 */
4135
4136 pwr_now += sds->busiest->sgp->power *
4137 min(sds->busiest_load_per_task, sds->max_load);
4138 pwr_now += sds->this->sgp->power *
4139 min(sds->this_load_per_task, sds->this_load);
4140 pwr_now /= SCHED_POWER_SCALE;
4141
4142 /* Amount of load we'd subtract */
4143 tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
4144 sds->busiest->sgp->power;
4145 if (sds->max_load > tmp)
4146 pwr_move += sds->busiest->sgp->power *
4147 min(sds->busiest_load_per_task, sds->max_load - tmp);
4148
4149 /* Amount of load we'd add */
4150 if (sds->max_load * sds->busiest->sgp->power <
4151 sds->busiest_load_per_task * SCHED_POWER_SCALE)
4152 tmp = (sds->max_load * sds->busiest->sgp->power) /
4153 sds->this->sgp->power;
4154 else
4155 tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
4156 sds->this->sgp->power;
4157 pwr_move += sds->this->sgp->power *
4158 min(sds->this_load_per_task, sds->this_load + tmp);
4159 pwr_move /= SCHED_POWER_SCALE;
4160
4161 /* Move if we gain throughput */
4162 if (pwr_move > pwr_now)
4163 *imbalance = sds->busiest_load_per_task;
4164}
4165
4166/**
4167 * calculate_imbalance - Calculate the amount of imbalance present within the
4168 * groups of a given sched_domain during load balance.
4169 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
4170 * @this_cpu: Cpu for which currently load balance is being performed.
4171 * @imbalance: The variable to store the imbalance.
4172 */
4173static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
4174 unsigned long *imbalance)
4175{
4176 unsigned long max_pull, load_above_capacity = ~0UL;
4177
4178 sds->busiest_load_per_task /= sds->busiest_nr_running;
4179 if (sds->group_imb) {
4180 sds->busiest_load_per_task =
4181 min(sds->busiest_load_per_task, sds->avg_load);
4182 }
4183
4184 /*
4185 * In the presence of smp nice balancing, certain scenarios can have
4186 * max load less than avg load(as we skip the groups at or below
4187 * its cpu_power, while calculating max_load..)
4188 */
4189 if (sds->max_load < sds->avg_load) {
4190 *imbalance = 0;
4191 return fix_small_imbalance(sds, this_cpu, imbalance);
4192 }
4193
4194 if (!sds->group_imb) {
4195 /*
4196 * Don't want to pull so many tasks that a group would go idle.
4197 */
4198 load_above_capacity = (sds->busiest_nr_running -
4199 sds->busiest_group_capacity);
4200
4201 load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);
4202
4203 load_above_capacity /= sds->busiest->sgp->power;
4204 }
4205
4206 /*
4207 * We're trying to get all the cpus to the average_load, so we don't
4208 * want to push ourselves above the average load, nor do we wish to
4209 * reduce the max loaded cpu below the average load. At the same time,
4210 * we also don't want to reduce the group load below the group capacity
4211 * (so that we can implement power-savings policies etc). Thus we look
4212 * for the minimum possible imbalance.
4213 * Be careful of negative numbers as they'll appear as very large values
4214 * with unsigned longs.
4215 */
4216 max_pull = min(sds->max_load - sds->avg_load, load_above_capacity);
4217
4218 /* How much load to actually move to equalise the imbalance */
4219 *imbalance = min(max_pull * sds->busiest->sgp->power,
4220 (sds->avg_load - sds->this_load) * sds->this->sgp->power)
4221 / SCHED_POWER_SCALE;
4222
4223 /*
4224 * if *imbalance is less than the average load per runnable task
4225 * there is no guarantee that any tasks will be moved so we'll have
4226 * a think about bumping its value to force at least one task to be
4227 * moved
4228 */
4229 if (*imbalance < sds->busiest_load_per_task)
4230 return fix_small_imbalance(sds, this_cpu, imbalance);
4231
4232}
4233
4234/******* find_busiest_group() helpers end here *********************/
4235
4236/**
4237 * find_busiest_group - Returns the busiest group within the sched_domain
4238 * if there is an imbalance. If there isn't an imbalance, and
4239 * the user has opted for power-savings, it returns a group whose
4240 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
4241 * such a group exists.
4242 *
4243 * Also calculates the amount of weighted load which should be moved
4244 * to restore balance.
4245 *
4246 * @sd: The sched_domain whose busiest group is to be returned.
4247 * @this_cpu: The cpu for which load balancing is currently being performed.
4248 * @imbalance: Variable which stores amount of weighted load which should
4249 * be moved to restore balance/put a group to idle.
4250 * @idle: The idle status of this_cpu.
4251 * @cpus: The set of CPUs under consideration for load-balancing.
4252 * @balance: Pointer to a variable indicating if this_cpu
4253 * is the appropriate cpu to perform load balancing at this_level.
4254 *
4255 * Returns: - the busiest group if imbalance exists.
4256 * - If no imbalance and user has opted for power-savings balance,
4257 * return the least loaded group whose CPUs can be
4258 * put to idle by rebalancing its tasks onto our group.
4259 */
4260static struct sched_group *
4261find_busiest_group(struct sched_domain *sd, int this_cpu,
4262 unsigned long *imbalance, enum cpu_idle_type idle,
4263 const struct cpumask *cpus, int *balance)
4264{
4265 struct sd_lb_stats sds;
4266
4267 memset(&sds, 0, sizeof(sds));
4268
4269 /*
4270 * Compute the various statistics relavent for load balancing at
4271 * this level.
4272 */
4273 update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds);
4274
4275 /*
4276 * this_cpu is not the appropriate cpu to perform load balancing at
4277 * this level.
4278 */
4279 if (!(*balance))
4280 goto ret;
4281
4282 if ((idle == CPU_IDLE || idle == CPU_NEWLY_IDLE) &&
4283 check_asym_packing(sd, &sds, this_cpu, imbalance))
4284 return sds.busiest;
4285
4286 /* There is no busy sibling group to pull tasks from */
4287 if (!sds.busiest || sds.busiest_nr_running == 0)
4288 goto out_balanced;
4289
4290 sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr;
4291
4292 /*
4293 * If the busiest group is imbalanced the below checks don't
4294 * work because they assumes all things are equal, which typically
4295 * isn't true due to cpus_allowed constraints and the like.
4296 */
4297 if (sds.group_imb)
4298 goto force_balance;
4299
4300 /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
4301 if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity &&
4302 !sds.busiest_has_capacity)
4303 goto force_balance;
4304
4305 /*
4306 * If the local group is more busy than the selected busiest group
4307 * don't try and pull any tasks.
4308 */
4309 if (sds.this_load >= sds.max_load)
4310 goto out_balanced;
4311
4312 /*
4313 * Don't pull any tasks if this group is already above the domain
4314 * average load.
4315 */
4316 if (sds.this_load >= sds.avg_load)
4317 goto out_balanced;
4318
4319 if (idle == CPU_IDLE) {
4320 /*
4321 * This cpu is idle. If the busiest group load doesn't
4322 * have more tasks than the number of available cpu's and
4323 * there is no imbalance between this and busiest group
4324 * wrt to idle cpu's, it is balanced.
4325 */
4326 if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) &&
4327 sds.busiest_nr_running <= sds.busiest_group_weight)
4328 goto out_balanced;
4329 } else {
4330 /*
4331 * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use
4332 * imbalance_pct to be conservative.
4333 */
4334 if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
4335 goto out_balanced;
4336 }
4337
4338force_balance:
4339 /* Looks like there is an imbalance. Compute it */
4340 calculate_imbalance(&sds, this_cpu, imbalance);
4341 return sds.busiest;
4342
4343out_balanced:
4344 /*
4345 * There is no obvious imbalance. But check if we can do some balancing
4346 * to save power.
4347 */
4348 if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
4349 return sds.busiest;
4350ret:
4351 *imbalance = 0;
4352 return NULL;
4353}
4354
4355/*
4356 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4357 */
4358static struct rq *
4359find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
4360 enum cpu_idle_type idle, unsigned long imbalance,
4361 const struct cpumask *cpus)
4362{
4363 struct rq *busiest = NULL, *rq;
4364 unsigned long max_load = 0;
4365 int i;
4366
4367 for_each_cpu(i, sched_group_cpus(group)) {
4368 unsigned long power = power_of(i);
4369 unsigned long capacity = DIV_ROUND_CLOSEST(power,
4370 SCHED_POWER_SCALE);
4371 unsigned long wl;
4372
4373 if (!capacity)
4374 capacity = fix_small_capacity(sd, group);
4375
4376 if (!cpumask_test_cpu(i, cpus))
4377 continue;
4378
4379 rq = cpu_rq(i);
4380 wl = weighted_cpuload(i);
4381
4382 /*
4383 * When comparing with imbalance, use weighted_cpuload()
4384 * which is not scaled with the cpu power.
4385 */
4386 if (capacity && rq->nr_running == 1 && wl > imbalance)
4387 continue;
4388
4389 /*
4390 * For the load comparisons with the other cpu's, consider
4391 * the weighted_cpuload() scaled with the cpu power, so that
4392 * the load can be moved away from the cpu that is potentially
4393 * running at a lower capacity.
4394 */
4395 wl = (wl * SCHED_POWER_SCALE) / power;
4396
4397 if (wl > max_load) {
4398 max_load = wl;
4399 busiest = rq;
4400 }
4401 }
4402
4403 return busiest;
4404}
4405
4406/*
4407 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4408 * so long as it is large enough.
4409 */
4410#define MAX_PINNED_INTERVAL 512
4411
4412/* Working cpumask for load_balance and load_balance_newidle. */
4413DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
4414
4415static int need_active_balance(struct sched_domain *sd, int idle,
4416 int busiest_cpu, int this_cpu)
4417{
4418 if (idle == CPU_NEWLY_IDLE) {
4419
4420 /*
4421 * ASYM_PACKING needs to force migrate tasks from busy but
4422 * higher numbered CPUs in order to pack all tasks in the
4423 * lowest numbered CPUs.
4424 */
4425 if ((sd->flags & SD_ASYM_PACKING) && busiest_cpu > this_cpu)
4426 return 1;
4427
4428 /*
4429 * The only task running in a non-idle cpu can be moved to this
4430 * cpu in an attempt to completely freeup the other CPU
4431 * package.
4432 *
4433 * The package power saving logic comes from
4434 * find_busiest_group(). If there are no imbalance, then
4435 * f_b_g() will return NULL. However when sched_mc={1,2} then
4436 * f_b_g() will select a group from which a running task may be
4437 * pulled to this cpu in order to make the other package idle.
4438 * If there is no opportunity to make a package idle and if
4439 * there are no imbalance, then f_b_g() will return NULL and no
4440 * action will be taken in load_balance_newidle().
4441 *
4442 * Under normal task pull operation due to imbalance, there
4443 * will be more than one task in the source run queue and
4444 * move_tasks() will succeed. ld_moved will be true and this
4445 * active balance code will not be triggered.
4446 */
4447 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
4448 return 0;
4449 }
4450
4451 return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
4452}
4453
4454static int active_load_balance_cpu_stop(void *data);
4455
4456/*
4457 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4458 * tasks if there is an imbalance.
4459 */
4460static int load_balance(int this_cpu, struct rq *this_rq,
4461 struct sched_domain *sd, enum cpu_idle_type idle,
4462 int *balance)
4463{
4464 int ld_moved, all_pinned = 0, active_balance = 0;
4465 struct sched_group *group;
4466 unsigned long imbalance;
4467 struct rq *busiest;
4468 unsigned long flags;
4469 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
4470
4471 cpumask_copy(cpus, cpu_active_mask);
4472
4473 schedstat_inc(sd, lb_count[idle]);
4474
4475redo:
4476 group = find_busiest_group(sd, this_cpu, &imbalance, idle,
4477 cpus, balance);
4478
4479 if (*balance == 0)
4480 goto out_balanced;
4481
4482 if (!group) {
4483 schedstat_inc(sd, lb_nobusyg[idle]);
4484 goto out_balanced;
4485 }
4486
4487 busiest = find_busiest_queue(sd, group, idle, imbalance, cpus);
4488 if (!busiest) {
4489 schedstat_inc(sd, lb_nobusyq[idle]);
4490 goto out_balanced;
4491 }
4492
4493 BUG_ON(busiest == this_rq);
4494
4495 schedstat_add(sd, lb_imbalance[idle], imbalance);
4496
4497 ld_moved = 0;
4498 if (busiest->nr_running > 1) {
4499 /*
4500 * Attempt to move tasks. If find_busiest_group has found
4501 * an imbalance but busiest->nr_running <= 1, the group is
4502 * still unbalanced. ld_moved simply stays zero, so it is
4503 * correctly treated as an imbalance.
4504 */
4505 all_pinned = 1;
4506 local_irq_save(flags);
4507 double_rq_lock(this_rq, busiest);
4508 ld_moved = move_tasks(this_rq, this_cpu, busiest,
4509 imbalance, sd, idle, &all_pinned);
4510 double_rq_unlock(this_rq, busiest);
4511 local_irq_restore(flags);
4512
4513 /*
4514 * some other cpu did the load balance for us.
4515 */
4516 if (ld_moved && this_cpu != smp_processor_id())
4517 resched_cpu(this_cpu);
4518
4519 /* All tasks on this runqueue were pinned by CPU affinity */
4520 if (unlikely(all_pinned)) {
4521 cpumask_clear_cpu(cpu_of(busiest), cpus);
4522 if (!cpumask_empty(cpus))
4523 goto redo;
4524 goto out_balanced;
4525 }
4526 }
4527
4528 if (!ld_moved) {
4529 schedstat_inc(sd, lb_failed[idle]);
4530 /*
4531 * Increment the failure counter only on periodic balance.
4532 * We do not want newidle balance, which can be very
4533 * frequent, pollute the failure counter causing
4534 * excessive cache_hot migrations and active balances.
4535 */
4536 if (idle != CPU_NEWLY_IDLE)
4537 sd->nr_balance_failed++;
4538
4539 if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) {
4540 raw_spin_lock_irqsave(&busiest->lock, flags);
4541
4542 /* don't kick the active_load_balance_cpu_stop,
4543 * if the curr task on busiest cpu can't be
4544 * moved to this_cpu
4545 */
4546 if (!cpumask_test_cpu(this_cpu,
4547 tsk_cpus_allowed(busiest->curr))) {
4548 raw_spin_unlock_irqrestore(&busiest->lock,
4549 flags);
4550 all_pinned = 1;
4551 goto out_one_pinned;
4552 }
4553
4554 /*
4555 * ->active_balance synchronizes accesses to
4556 * ->active_balance_work. Once set, it's cleared
4557 * only after active load balance is finished.
4558 */
4559 if (!busiest->active_balance) {
4560 busiest->active_balance = 1;
4561 busiest->push_cpu = this_cpu;
4562 active_balance = 1;
4563 }
4564 raw_spin_unlock_irqrestore(&busiest->lock, flags);
4565
4566 if (active_balance)
4567 stop_one_cpu_nowait(cpu_of(busiest),
4568 active_load_balance_cpu_stop, busiest,
4569 &busiest->active_balance_work);
4570
4571 /*
4572 * We've kicked active balancing, reset the failure
4573 * counter.
4574 */
4575 sd->nr_balance_failed = sd->cache_nice_tries+1;
4576 }
4577 } else
4578 sd->nr_balance_failed = 0;
4579
4580 if (likely(!active_balance)) {
4581 /* We were unbalanced, so reset the balancing interval */
4582 sd->balance_interval = sd->min_interval;
4583 } else {
4584 /*
4585 * If we've begun active balancing, start to back off. This
4586 * case may not be covered by the all_pinned logic if there
4587 * is only 1 task on the busy runqueue (because we don't call
4588 * move_tasks).
4589 */
4590 if (sd->balance_interval < sd->max_interval)
4591 sd->balance_interval *= 2;
4592 }
4593
4594 goto out;
4595
4596out_balanced:
4597 schedstat_inc(sd, lb_balanced[idle]);
4598
4599 sd->nr_balance_failed = 0;
4600
4601out_one_pinned:
4602 /* tune up the balancing interval */
4603 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
4604 (sd->balance_interval < sd->max_interval))
4605 sd->balance_interval *= 2;
4606
4607 ld_moved = 0;
4608out:
4609 return ld_moved;
4610}
4611
4612/*
4613 * idle_balance is called by schedule() if this_cpu is about to become
4614 * idle. Attempts to pull tasks from other CPUs.
4615 */
4616void idle_balance(int this_cpu, struct rq *this_rq)
4617{
4618 struct sched_domain *sd;
4619 int pulled_task = 0;
4620 unsigned long next_balance = jiffies + HZ;
4621
4622 this_rq->idle_stamp = this_rq->clock;
4623
4624 if (this_rq->avg_idle < sysctl_sched_migration_cost)
4625 return;
4626
4627 /*
4628 * Drop the rq->lock, but keep IRQ/preempt disabled.
4629 */
4630 raw_spin_unlock(&this_rq->lock);
4631
4632 update_shares(this_cpu);
4633 rcu_read_lock();
4634 for_each_domain(this_cpu, sd) {
4635 unsigned long interval;
4636 int balance = 1;
4637
4638 if (!(sd->flags & SD_LOAD_BALANCE))
4639 continue;
4640
4641 if (sd->flags & SD_BALANCE_NEWIDLE) {
4642 /* If we've pulled tasks over stop searching: */
4643 pulled_task = load_balance(this_cpu, this_rq,
4644 sd, CPU_NEWLY_IDLE, &balance);
4645 }
4646
4647 interval = msecs_to_jiffies(sd->balance_interval);
4648 if (time_after(next_balance, sd->last_balance + interval))
4649 next_balance = sd->last_balance + interval;
4650 if (pulled_task) {
4651 this_rq->idle_stamp = 0;
4652 break;
4653 }
4654 }
4655 rcu_read_unlock();
4656
4657 raw_spin_lock(&this_rq->lock);
4658
4659 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
4660 /*
4661 * We are going idle. next_balance may be set based on
4662 * a busy processor. So reset next_balance.
4663 */
4664 this_rq->next_balance = next_balance;
4665 }
4666}
4667
4668/*
4669 * active_load_balance_cpu_stop is run by cpu stopper. It pushes
4670 * running tasks off the busiest CPU onto idle CPUs. It requires at
4671 * least 1 task to be running on each physical CPU where possible, and
4672 * avoids physical / logical imbalances.
4673 */
4674static int active_load_balance_cpu_stop(void *data)
4675{
4676 struct rq *busiest_rq = data;
4677 int busiest_cpu = cpu_of(busiest_rq);
4678 int target_cpu = busiest_rq->push_cpu;
4679 struct rq *target_rq = cpu_rq(target_cpu);
4680 struct sched_domain *sd;
4681
4682 raw_spin_lock_irq(&busiest_rq->lock);
4683
4684 /* make sure the requested cpu hasn't gone down in the meantime */
4685 if (unlikely(busiest_cpu != smp_processor_id() ||
4686 !busiest_rq->active_balance))
4687 goto out_unlock;
4688
4689 /* Is there any task to move? */
4690 if (busiest_rq->nr_running <= 1)
4691 goto out_unlock;
4692
4693 /*
4694 * This condition is "impossible", if it occurs
4695 * we need to fix it. Originally reported by
4696 * Bjorn Helgaas on a 128-cpu setup.
4697 */
4698 BUG_ON(busiest_rq == target_rq);
4699
4700 /* move a task from busiest_rq to target_rq */
4701 double_lock_balance(busiest_rq, target_rq);
4702
4703 /* Search for an sd spanning us and the target CPU. */
4704 rcu_read_lock();
4705 for_each_domain(target_cpu, sd) {
4706 if ((sd->flags & SD_LOAD_BALANCE) &&
4707 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
4708 break;
4709 }
4710
4711 if (likely(sd)) {
4712 schedstat_inc(sd, alb_count);
4713
4714 if (move_one_task(target_rq, target_cpu, busiest_rq,
4715 sd, CPU_IDLE))
4716 schedstat_inc(sd, alb_pushed);
4717 else
4718 schedstat_inc(sd, alb_failed);
4719 }
4720 rcu_read_unlock();
4721 double_unlock_balance(busiest_rq, target_rq);
4722out_unlock:
4723 busiest_rq->active_balance = 0;
4724 raw_spin_unlock_irq(&busiest_rq->lock);
4725 return 0;
4726}
4727
4728#ifdef CONFIG_NO_HZ
4729/*
4730 * idle load balancing details
4731 * - When one of the busy CPUs notice that there may be an idle rebalancing
4732 * needed, they will kick the idle load balancer, which then does idle
4733 * load balancing for all the idle CPUs.
4734 */
4735static struct {
4736 cpumask_var_t idle_cpus_mask;
4737 atomic_t nr_cpus;
4738 unsigned long next_balance; /* in jiffy units */
4739} nohz ____cacheline_aligned;
4740
4741#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4742/**
4743 * lowest_flag_domain - Return lowest sched_domain containing flag.
4744 * @cpu: The cpu whose lowest level of sched domain is to
4745 * be returned.
4746 * @flag: The flag to check for the lowest sched_domain
4747 * for the given cpu.
4748 *
4749 * Returns the lowest sched_domain of a cpu which contains the given flag.
4750 */
4751static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
4752{
4753 struct sched_domain *sd;
4754
4755 for_each_domain(cpu, sd)
4756 if (sd->flags & flag)
4757 break;
4758
4759 return sd;
4760}
4761
4762/**
4763 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4764 * @cpu: The cpu whose domains we're iterating over.
4765 * @sd: variable holding the value of the power_savings_sd
4766 * for cpu.
4767 * @flag: The flag to filter the sched_domains to be iterated.
4768 *
4769 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4770 * set, starting from the lowest sched_domain to the highest.
4771 */
4772#define for_each_flag_domain(cpu, sd, flag) \
4773 for (sd = lowest_flag_domain(cpu, flag); \
4774 (sd && (sd->flags & flag)); sd = sd->parent)
4775
4776/**
4777 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4778 * @cpu: The cpu which is nominating a new idle_load_balancer.
4779 *
4780 * Returns: Returns the id of the idle load balancer if it exists,
4781 * Else, returns >= nr_cpu_ids.
4782 *
4783 * This algorithm picks the idle load balancer such that it belongs to a
4784 * semi-idle powersavings sched_domain. The idea is to try and avoid
4785 * completely idle packages/cores just for the purpose of idle load balancing
4786 * when there are other idle cpu's which are better suited for that job.
4787 */
4788static int find_new_ilb(int cpu)
4789{
4790 int ilb = cpumask_first(nohz.idle_cpus_mask);
4791 struct sched_group *ilbg;
4792 struct sched_domain *sd;
4793
4794 /*
4795 * Have idle load balancer selection from semi-idle packages only
4796 * when power-aware load balancing is enabled
4797 */
4798 if (!(sched_smt_power_savings || sched_mc_power_savings))
4799 goto out_done;
4800
4801 /*
4802 * Optimize for the case when we have no idle CPUs or only one
4803 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4804 */
4805 if (cpumask_weight(nohz.idle_cpus_mask) < 2)
4806 goto out_done;
4807
4808 rcu_read_lock();
4809 for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
4810 ilbg = sd->groups;
4811
4812 do {
4813 if (ilbg->group_weight !=
4814 atomic_read(&ilbg->sgp->nr_busy_cpus)) {
4815 ilb = cpumask_first_and(nohz.idle_cpus_mask,
4816 sched_group_cpus(ilbg));
4817 goto unlock;
4818 }
4819
4820 ilbg = ilbg->next;
4821
4822 } while (ilbg != sd->groups);
4823 }
4824unlock:
4825 rcu_read_unlock();
4826
4827out_done:
4828 if (ilb < nr_cpu_ids && idle_cpu(ilb))
4829 return ilb;
4830
4831 return nr_cpu_ids;
4832}
4833#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4834static inline int find_new_ilb(int call_cpu)
4835{
4836 return nr_cpu_ids;
4837}
4838#endif
4839
4840/*
4841 * Kick a CPU to do the nohz balancing, if it is time for it. We pick the
4842 * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle
4843 * CPU (if there is one).
4844 */
4845static void nohz_balancer_kick(int cpu)
4846{
4847 int ilb_cpu;
4848
4849 nohz.next_balance++;
4850
4851 ilb_cpu = find_new_ilb(cpu);
4852
4853 if (ilb_cpu >= nr_cpu_ids)
4854 return;
4855
4856 if (test_and_set_bit(NOHZ_BALANCE_KICK, nohz_flags(ilb_cpu)))
4857 return;
4858 /*
4859 * Use smp_send_reschedule() instead of resched_cpu().
4860 * This way we generate a sched IPI on the target cpu which
4861 * is idle. And the softirq performing nohz idle load balance
4862 * will be run before returning from the IPI.
4863 */
4864 smp_send_reschedule(ilb_cpu);
4865 return;
4866}
4867
4868static inline void set_cpu_sd_state_busy(void)
4869{
4870 struct sched_domain *sd;
4871 int cpu = smp_processor_id();
4872
4873 if (!test_bit(NOHZ_IDLE, nohz_flags(cpu)))
4874 return;
4875 clear_bit(NOHZ_IDLE, nohz_flags(cpu));
4876
4877 rcu_read_lock();
4878 for_each_domain(cpu, sd)
4879 atomic_inc(&sd->groups->sgp->nr_busy_cpus);
4880 rcu_read_unlock();
4881}
4882
4883void set_cpu_sd_state_idle(void)
4884{
4885 struct sched_domain *sd;
4886 int cpu = smp_processor_id();
4887
4888 if (test_bit(NOHZ_IDLE, nohz_flags(cpu)))
4889 return;
4890 set_bit(NOHZ_IDLE, nohz_flags(cpu));
4891
4892 rcu_read_lock();
4893 for_each_domain(cpu, sd)
4894 atomic_dec(&sd->groups->sgp->nr_busy_cpus);
4895 rcu_read_unlock();
4896}
4897
4898/*
4899 * This routine will record that this cpu is going idle with tick stopped.
4900 * This info will be used in performing idle load balancing in the future.
4901 */
4902void select_nohz_load_balancer(int stop_tick)
4903{
4904 int cpu = smp_processor_id();
4905
4906 if (stop_tick) {
4907 if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
4908 return;
4909
4910 cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
4911 atomic_inc(&nohz.nr_cpus);
4912 set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
4913 }
4914 return;
4915}
4916#endif
4917
4918static DEFINE_SPINLOCK(balancing);
4919
4920static unsigned long __read_mostly max_load_balance_interval = HZ/10;
4921
4922/*
4923 * Scale the max load_balance interval with the number of CPUs in the system.
4924 * This trades load-balance latency on larger machines for less cross talk.
4925 */
4926void update_max_interval(void)
4927{
4928 max_load_balance_interval = HZ*num_online_cpus()/10;
4929}
4930
4931/*
4932 * It checks each scheduling domain to see if it is due to be balanced,
4933 * and initiates a balancing operation if so.
4934 *
4935 * Balancing parameters are set up in arch_init_sched_domains.
4936 */
4937static void rebalance_domains(int cpu, enum cpu_idle_type idle)
4938{
4939 int balance = 1;
4940 struct rq *rq = cpu_rq(cpu);
4941 unsigned long interval;
4942 struct sched_domain *sd;
4943 /* Earliest time when we have to do rebalance again */
4944 unsigned long next_balance = jiffies + 60*HZ;
4945 int update_next_balance = 0;
4946 int need_serialize;
4947
4948 update_shares(cpu);
4949
4950 rcu_read_lock();
4951 for_each_domain(cpu, sd) {
4952 if (!(sd->flags & SD_LOAD_BALANCE))
4953 continue;
4954
4955 interval = sd->balance_interval;
4956 if (idle != CPU_IDLE)
4957 interval *= sd->busy_factor;
4958
4959 /* scale ms to jiffies */
4960 interval = msecs_to_jiffies(interval);
4961 interval = clamp(interval, 1UL, max_load_balance_interval);
4962
4963 need_serialize = sd->flags & SD_SERIALIZE;
4964
4965 if (need_serialize) {
4966 if (!spin_trylock(&balancing))
4967 goto out;
4968 }
4969
4970 if (time_after_eq(jiffies, sd->last_balance + interval)) {
4971 if (load_balance(cpu, rq, sd, idle, &balance)) {
4972 /*
4973 * We've pulled tasks over so either we're no
4974 * longer idle.
4975 */
4976 idle = CPU_NOT_IDLE;
4977 }
4978 sd->last_balance = jiffies;
4979 }
4980 if (need_serialize)
4981 spin_unlock(&balancing);
4982out:
4983 if (time_after(next_balance, sd->last_balance + interval)) {
4984 next_balance = sd->last_balance + interval;
4985 update_next_balance = 1;
4986 }
4987
4988 /*
4989 * Stop the load balance at this level. There is another
4990 * CPU in our sched group which is doing load balancing more
4991 * actively.
4992 */
4993 if (!balance)
4994 break;
4995 }
4996 rcu_read_unlock();
4997
4998 /*
4999 * next_balance will be updated only when there is a need.
5000 * When the cpu is attached to null domain for ex, it will not be
5001 * updated.
5002 */
5003 if (likely(update_next_balance))
5004 rq->next_balance = next_balance;
5005}
5006
5007#ifdef CONFIG_NO_HZ
5008/*
5009 * In CONFIG_NO_HZ case, the idle balance kickee will do the
5010 * rebalancing for all the cpus for whom scheduler ticks are stopped.
5011 */
5012static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
5013{
5014 struct rq *this_rq = cpu_rq(this_cpu);
5015 struct rq *rq;
5016 int balance_cpu;
5017
5018 if (idle != CPU_IDLE ||
5019 !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)))
5020 goto end;
5021
5022 for_each_cpu(balance_cpu, nohz.idle_cpus_mask) {
5023 if (balance_cpu == this_cpu || !idle_cpu(balance_cpu))
5024 continue;
5025
5026 /*
5027 * If this cpu gets work to do, stop the load balancing
5028 * work being done for other cpus. Next load
5029 * balancing owner will pick it up.
5030 */
5031 if (need_resched())
5032 break;
5033
5034 raw_spin_lock_irq(&this_rq->lock);
5035 update_rq_clock(this_rq);
5036 update_cpu_load(this_rq);
5037 raw_spin_unlock_irq(&this_rq->lock);
5038
5039 rebalance_domains(balance_cpu, CPU_IDLE);
5040
5041 rq = cpu_rq(balance_cpu);
5042 if (time_after(this_rq->next_balance, rq->next_balance))
5043 this_rq->next_balance = rq->next_balance;
5044 }
5045 nohz.next_balance = this_rq->next_balance;
5046end:
5047 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu));
5048}
5049
5050/*
5051 * Current heuristic for kicking the idle load balancer in the presence
5052 * of an idle cpu is the system.
5053 * - This rq has more than one task.
5054 * - At any scheduler domain level, this cpu's scheduler group has multiple
5055 * busy cpu's exceeding the group's power.
5056 * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler
5057 * domain span are idle.
5058 */
5059static inline int nohz_kick_needed(struct rq *rq, int cpu)
5060{
5061 unsigned long now = jiffies;
5062 struct sched_domain *sd;
5063
5064 if (unlikely(idle_cpu(cpu)))
5065 return 0;
5066
5067 /*
5068 * We may be recently in ticked or tickless idle mode. At the first
5069 * busy tick after returning from idle, we will update the busy stats.
5070 */
5071 set_cpu_sd_state_busy();
5072 if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
5073 clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
5074 cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
5075 atomic_dec(&nohz.nr_cpus);
5076 }
5077
5078 /*
5079 * None are in tickless mode and hence no need for NOHZ idle load
5080 * balancing.
5081 */
5082 if (likely(!atomic_read(&nohz.nr_cpus)))
5083 return 0;
5084
5085 if (time_before(now, nohz.next_balance))
5086 return 0;
5087
5088 if (rq->nr_running >= 2)
5089 goto need_kick;
5090
5091 rcu_read_lock();
5092 for_each_domain(cpu, sd) {
5093 struct sched_group *sg = sd->groups;
5094 struct sched_group_power *sgp = sg->sgp;
5095 int nr_busy = atomic_read(&sgp->nr_busy_cpus);
5096
5097 if (sd->flags & SD_SHARE_PKG_RESOURCES && nr_busy > 1)
5098 goto need_kick_unlock;
5099
5100 if (sd->flags & SD_ASYM_PACKING && nr_busy != sg->group_weight
5101 && (cpumask_first_and(nohz.idle_cpus_mask,
5102 sched_domain_span(sd)) < cpu))
5103 goto need_kick_unlock;
5104
5105 if (!(sd->flags & (SD_SHARE_PKG_RESOURCES | SD_ASYM_PACKING)))
5106 break;
5107 }
5108 rcu_read_unlock();
5109 return 0;
5110
5111need_kick_unlock:
5112 rcu_read_unlock();
5113need_kick:
5114 return 1;
5115}
5116#else
5117static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
5118#endif
5119
5120/*
5121 * run_rebalance_domains is triggered when needed from the scheduler tick.
5122 * Also triggered for nohz idle balancing (with nohz_balancing_kick set).
5123 */
5124static void run_rebalance_domains(struct softirq_action *h)
5125{
5126 int this_cpu = smp_processor_id();
5127 struct rq *this_rq = cpu_rq(this_cpu);
5128 enum cpu_idle_type idle = this_rq->idle_balance ?
5129 CPU_IDLE : CPU_NOT_IDLE;
5130
5131 rebalance_domains(this_cpu, idle);
5132
5133 /*
5134 * If this cpu has a pending nohz_balance_kick, then do the
5135 * balancing on behalf of the other idle cpus whose ticks are
5136 * stopped.
5137 */
5138 nohz_idle_balance(this_cpu, idle);
5139}
5140
5141static inline int on_null_domain(int cpu)
5142{
5143 return !rcu_dereference_sched(cpu_rq(cpu)->sd);
5144}
5145
5146/*
5147 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
5148 */
5149void trigger_load_balance(struct rq *rq, int cpu)
5150{
5151 /* Don't need to rebalance while attached to NULL domain */
5152 if (time_after_eq(jiffies, rq->next_balance) &&
5153 likely(!on_null_domain(cpu)))
5154 raise_softirq(SCHED_SOFTIRQ);
5155#ifdef CONFIG_NO_HZ
5156 if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu)))
5157 nohz_balancer_kick(cpu);
5158#endif
5159}
5160
5161static void rq_online_fair(struct rq *rq)
5162{
5163 update_sysctl();
5164}
5165
5166static void rq_offline_fair(struct rq *rq)
5167{
5168 update_sysctl();
5169}
5170
5171#endif /* CONFIG_SMP */
5172
5173/*
5174 * scheduler tick hitting a task of our scheduling class:
5175 */
5176static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
5177{
5178 struct cfs_rq *cfs_rq;
5179 struct sched_entity *se = &curr->se;
5180
5181 for_each_sched_entity(se) {
5182 cfs_rq = cfs_rq_of(se);
5183 entity_tick(cfs_rq, se, queued);
5184 }
5185}
5186
5187/*
5188 * called on fork with the child task as argument from the parent's context
5189 * - child not yet on the tasklist
5190 * - preemption disabled
5191 */
5192static void task_fork_fair(struct task_struct *p)
5193{
5194 struct cfs_rq *cfs_rq = task_cfs_rq(current);
5195 struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
5196 int this_cpu = smp_processor_id();
5197 struct rq *rq = this_rq();
5198 unsigned long flags;
5199
5200 raw_spin_lock_irqsave(&rq->lock, flags);
5201
5202 update_rq_clock(rq);
5203
5204 if (unlikely(task_cpu(p) != this_cpu)) {
5205 rcu_read_lock();
5206 __set_task_cpu(p, this_cpu);
5207 rcu_read_unlock();
5208 }
5209
5210 update_curr(cfs_rq);
5211
5212 if (curr)
5213 se->vruntime = curr->vruntime;
5214 place_entity(cfs_rq, se, 1);
5215
5216 if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) {
5217 /*
5218 * Upon rescheduling, sched_class::put_prev_task() will place
5219 * 'current' within the tree based on its new key value.
5220 */
5221 swap(curr->vruntime, se->vruntime);
5222 resched_task(rq->curr);
5223 }
5224
5225 se->vruntime -= cfs_rq->min_vruntime;
5226
5227 raw_spin_unlock_irqrestore(&rq->lock, flags);
5228}
5229
5230/*
5231 * Priority of the task has changed. Check to see if we preempt
5232 * the current task.
5233 */
5234static void
5235prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
5236{
5237 if (!p->se.on_rq)
5238 return;
5239
5240 /*
5241 * Reschedule if we are currently running on this runqueue and
5242 * our priority decreased, or if we are not currently running on
5243 * this runqueue and our priority is higher than the current's
5244 */
5245 if (rq->curr == p) {
5246 if (p->prio > oldprio)
5247 resched_task(rq->curr);
5248 } else
5249 check_preempt_curr(rq, p, 0);
5250}
5251
5252static void switched_from_fair(struct rq *rq, struct task_struct *p)
5253{
5254 struct sched_entity *se = &p->se;
5255 struct cfs_rq *cfs_rq = cfs_rq_of(se);
5256
5257 /*
5258 * Ensure the task's vruntime is normalized, so that when its
5259 * switched back to the fair class the enqueue_entity(.flags=0) will
5260 * do the right thing.
5261 *
5262 * If it was on_rq, then the dequeue_entity(.flags=0) will already
5263 * have normalized the vruntime, if it was !on_rq, then only when
5264 * the task is sleeping will it still have non-normalized vruntime.
5265 */
5266 if (!se->on_rq && p->state != TASK_RUNNING) {
5267 /*
5268 * Fix up our vruntime so that the current sleep doesn't
5269 * cause 'unlimited' sleep bonus.
5270 */
5271 place_entity(cfs_rq, se, 0);
5272 se->vruntime -= cfs_rq->min_vruntime;
5273 }
5274}
5275
5276/*
5277 * We switched to the sched_fair class.
5278 */
5279static void switched_to_fair(struct rq *rq, struct task_struct *p)
5280{
5281 if (!p->se.on_rq)
5282 return;
5283
5284 /*
5285 * We were most likely switched from sched_rt, so
5286 * kick off the schedule if running, otherwise just see
5287 * if we can still preempt the current task.
5288 */
5289 if (rq->curr == p)
5290 resched_task(rq->curr);
5291 else
5292 check_preempt_curr(rq, p, 0);
5293}
5294
5295/* Account for a task changing its policy or group.
5296 *
5297 * This routine is mostly called to set cfs_rq->curr field when a task
5298 * migrates between groups/classes.
5299 */
5300static void set_curr_task_fair(struct rq *rq)
5301{
5302 struct sched_entity *se = &rq->curr->se;
5303
5304 for_each_sched_entity(se) {
5305 struct cfs_rq *cfs_rq = cfs_rq_of(se);
5306
5307 set_next_entity(cfs_rq, se);
5308 /* ensure bandwidth has been allocated on our new cfs_rq */
5309 account_cfs_rq_runtime(cfs_rq, 0);
5310 }
5311}
5312
5313void init_cfs_rq(struct cfs_rq *cfs_rq)
5314{
5315 cfs_rq->tasks_timeline = RB_ROOT;
5316 INIT_LIST_HEAD(&cfs_rq->tasks);
5317 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
5318#ifndef CONFIG_64BIT
5319 cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
5320#endif
5321}
5322
5323#ifdef CONFIG_FAIR_GROUP_SCHED
5324static void task_move_group_fair(struct task_struct *p, int on_rq)
5325{
5326 /*
5327 * If the task was not on the rq at the time of this cgroup movement
5328 * it must have been asleep, sleeping tasks keep their ->vruntime
5329 * absolute on their old rq until wakeup (needed for the fair sleeper
5330 * bonus in place_entity()).
5331 *
5332 * If it was on the rq, we've just 'preempted' it, which does convert
5333 * ->vruntime to a relative base.
5334 *
5335 * Make sure both cases convert their relative position when migrating
5336 * to another cgroup's rq. This does somewhat interfere with the
5337 * fair sleeper stuff for the first placement, but who cares.
5338 */
5339 if (!on_rq)
5340 p->se.vruntime -= cfs_rq_of(&p->se)->min_vruntime;
5341 set_task_rq(p, task_cpu(p));
5342 if (!on_rq)
5343 p->se.vruntime += cfs_rq_of(&p->se)->min_vruntime;
5344}
5345
5346void free_fair_sched_group(struct task_group *tg)
5347{
5348 int i;
5349
5350 destroy_cfs_bandwidth(tg_cfs_bandwidth(tg));
5351
5352 for_each_possible_cpu(i) {
5353 if (tg->cfs_rq)
5354 kfree(tg->cfs_rq[i]);
5355 if (tg->se)
5356 kfree(tg->se[i]);
5357 }
5358
5359 kfree(tg->cfs_rq);
5360 kfree(tg->se);
5361}
5362
5363int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
5364{
5365 struct cfs_rq *cfs_rq;
5366 struct sched_entity *se;
5367 int i;
5368
5369 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
5370 if (!tg->cfs_rq)
5371 goto err;
5372 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
5373 if (!tg->se)
5374 goto err;
5375
5376 tg->shares = NICE_0_LOAD;
5377
5378 init_cfs_bandwidth(tg_cfs_bandwidth(tg));
5379
5380 for_each_possible_cpu(i) {
5381 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
5382 GFP_KERNEL, cpu_to_node(i));
5383 if (!cfs_rq)
5384 goto err;
5385
5386 se = kzalloc_node(sizeof(struct sched_entity),
5387 GFP_KERNEL, cpu_to_node(i));
5388 if (!se)
5389 goto err_free_rq;
5390
5391 init_cfs_rq(cfs_rq);
5392 init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
5393 }
5394
5395 return 1;
5396
5397err_free_rq:
5398 kfree(cfs_rq);
5399err:
5400 return 0;
5401}
5402
5403void unregister_fair_sched_group(struct task_group *tg, int cpu)
5404{
5405 struct rq *rq = cpu_rq(cpu);
5406 unsigned long flags;
5407
5408 /*
5409 * Only empty task groups can be destroyed; so we can speculatively
5410 * check on_list without danger of it being re-added.
5411 */
5412 if (!tg->cfs_rq[cpu]->on_list)
5413 return;
5414
5415 raw_spin_lock_irqsave(&rq->lock, flags);
5416 list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
5417 raw_spin_unlock_irqrestore(&rq->lock, flags);
5418}
5419
5420void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
5421 struct sched_entity *se, int cpu,
5422 struct sched_entity *parent)
5423{
5424 struct rq *rq = cpu_rq(cpu);
5425
5426 cfs_rq->tg = tg;
5427 cfs_rq->rq = rq;
5428#ifdef CONFIG_SMP
5429 /* allow initial update_cfs_load() to truncate */
5430 cfs_rq->load_stamp = 1;
5431#endif
5432 init_cfs_rq_runtime(cfs_rq);
5433
5434 tg->cfs_rq[cpu] = cfs_rq;
5435 tg->se[cpu] = se;
5436
5437 /* se could be NULL for root_task_group */
5438 if (!se)
5439 return;
5440
5441 if (!parent)
5442 se->cfs_rq = &rq->cfs;
5443 else
5444 se->cfs_rq = parent->my_q;
5445
5446 se->my_q = cfs_rq;
5447 update_load_set(&se->load, 0);
5448 se->parent = parent;
5449}
5450
5451static DEFINE_MUTEX(shares_mutex);
5452
5453int sched_group_set_shares(struct task_group *tg, unsigned long shares)
5454{
5455 int i;
5456 unsigned long flags;
5457
5458 /*
5459 * We can't change the weight of the root cgroup.
5460 */
5461 if (!tg->se[0])
5462 return -EINVAL;
5463
5464 shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
5465
5466 mutex_lock(&shares_mutex);
5467 if (tg->shares == shares)
5468 goto done;
5469
5470 tg->shares = shares;
5471 for_each_possible_cpu(i) {
5472 struct rq *rq = cpu_rq(i);
5473 struct sched_entity *se;
5474
5475 se = tg->se[i];
5476 /* Propagate contribution to hierarchy */
5477 raw_spin_lock_irqsave(&rq->lock, flags);
5478 for_each_sched_entity(se)
5479 update_cfs_shares(group_cfs_rq(se));
5480 raw_spin_unlock_irqrestore(&rq->lock, flags);
5481 }
5482
5483done:
5484 mutex_unlock(&shares_mutex);
5485 return 0;
5486}
5487#else /* CONFIG_FAIR_GROUP_SCHED */
5488
5489void free_fair_sched_group(struct task_group *tg) { }
5490
5491int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
5492{
5493 return 1;
5494}
5495
5496void unregister_fair_sched_group(struct task_group *tg, int cpu) { }
5497
5498#endif /* CONFIG_FAIR_GROUP_SCHED */
5499
5500
5501static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task)
5502{
5503 struct sched_entity *se = &task->se;
5504 unsigned int rr_interval = 0;
5505
5506 /*
5507 * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise
5508 * idle runqueue:
5509 */
5510 if (rq->cfs.load.weight)
5511 rr_interval = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
5512
5513 return rr_interval;
5514}
5515
5516/*
5517 * All the scheduling class methods:
5518 */
5519const struct sched_class fair_sched_class = {
5520 .next = &idle_sched_class,
5521 .enqueue_task = enqueue_task_fair,
5522 .dequeue_task = dequeue_task_fair,
5523 .yield_task = yield_task_fair,
5524 .yield_to_task = yield_to_task_fair,
5525
5526 .check_preempt_curr = check_preempt_wakeup,
5527
5528 .pick_next_task = pick_next_task_fair,
5529 .put_prev_task = put_prev_task_fair,
5530
5531#ifdef CONFIG_SMP
5532 .select_task_rq = select_task_rq_fair,
5533
5534 .rq_online = rq_online_fair,
5535 .rq_offline = rq_offline_fair,
5536
5537 .task_waking = task_waking_fair,
5538#endif
5539
5540 .set_curr_task = set_curr_task_fair,
5541 .task_tick = task_tick_fair,
5542 .task_fork = task_fork_fair,
5543
5544 .prio_changed = prio_changed_fair,
5545 .switched_from = switched_from_fair,
5546 .switched_to = switched_to_fair,
5547
5548 .get_rr_interval = get_rr_interval_fair,
5549
5550#ifdef CONFIG_FAIR_GROUP_SCHED
5551 .task_move_group = task_move_group_fair,
5552#endif
5553};
5554
5555#ifdef CONFIG_SCHED_DEBUG
5556void print_cfs_stats(struct seq_file *m, int cpu)
5557{
5558 struct cfs_rq *cfs_rq;
5559
5560 rcu_read_lock();
5561 for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
5562 print_cfs_rq(m, cpu, cfs_rq);
5563 rcu_read_unlock();
5564}
5565#endif
5566
5567__init void init_sched_fair_class(void)
5568{
5569#ifdef CONFIG_SMP
5570 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
5571
5572#ifdef CONFIG_NO_HZ
5573 zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
5574#endif
5575#endif /* SMP */
5576
5577}
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
new file mode 100644
index 000000000000..e61fd73913d0
--- /dev/null
+++ b/kernel/sched/features.h
@@ -0,0 +1,70 @@
1/*
2 * Only give sleepers 50% of their service deficit. This allows
3 * them to run sooner, but does not allow tons of sleepers to
4 * rip the spread apart.
5 */
6SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
7
8/*
9 * Place new tasks ahead so that they do not starve already running
10 * tasks
11 */
12SCHED_FEAT(START_DEBIT, true)
13
14/*
15 * Based on load and program behaviour, see if it makes sense to place
16 * a newly woken task on the same cpu as the task that woke it --
17 * improve cache locality. Typically used with SYNC wakeups as
18 * generated by pipes and the like, see also SYNC_WAKEUPS.
19 */
20SCHED_FEAT(AFFINE_WAKEUPS, true)
21
22/*
23 * Prefer to schedule the task we woke last (assuming it failed
24 * wakeup-preemption), since its likely going to consume data we
25 * touched, increases cache locality.
26 */
27SCHED_FEAT(NEXT_BUDDY, false)
28
29/*
30 * Prefer to schedule the task that ran last (when we did
31 * wake-preempt) as that likely will touch the same data, increases
32 * cache locality.
33 */
34SCHED_FEAT(LAST_BUDDY, true)
35
36/*
37 * Consider buddies to be cache hot, decreases the likelyness of a
38 * cache buddy being migrated away, increases cache locality.
39 */
40SCHED_FEAT(CACHE_HOT_BUDDY, true)
41
42/*
43 * Use arch dependent cpu power functions
44 */
45SCHED_FEAT(ARCH_POWER, false)
46
47SCHED_FEAT(HRTICK, false)
48SCHED_FEAT(DOUBLE_TICK, false)
49SCHED_FEAT(LB_BIAS, true)
50
51/*
52 * Spin-wait on mutex acquisition when the mutex owner is running on
53 * another cpu -- assumes that when the owner is running, it will soon
54 * release the lock. Decreases scheduling overhead.
55 */
56SCHED_FEAT(OWNER_SPIN, true)
57
58/*
59 * Decrement CPU power based on time not spent running tasks
60 */
61SCHED_FEAT(NONTASK_POWER, true)
62
63/*
64 * Queue remote wakeups on the target CPU and process them
65 * using the scheduler IPI. Reduces rq->lock contention/bounces.
66 */
67SCHED_FEAT(TTWU_QUEUE, true)
68
69SCHED_FEAT(FORCE_SD_OVERLAP, false)
70SCHED_FEAT(RT_RUNTIME_SHARE, true)
diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c
new file mode 100644
index 000000000000..91b4c957f289
--- /dev/null
+++ b/kernel/sched/idle_task.c
@@ -0,0 +1,99 @@
1#include "sched.h"
2
3/*
4 * idle-task scheduling class.
5 *
6 * (NOTE: these are not related to SCHED_IDLE tasks which are
7 * handled in sched_fair.c)
8 */
9
10#ifdef CONFIG_SMP
11static int
12select_task_rq_idle(struct task_struct *p, int sd_flag, int flags)
13{
14 return task_cpu(p); /* IDLE tasks as never migrated */
15}
16#endif /* CONFIG_SMP */
17/*
18 * Idle tasks are unconditionally rescheduled:
19 */
20static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
21{
22 resched_task(rq->idle);
23}
24
25static struct task_struct *pick_next_task_idle(struct rq *rq)
26{
27 schedstat_inc(rq, sched_goidle);
28 calc_load_account_idle(rq);
29 return rq->idle;
30}
31
32/*
33 * It is not legal to sleep in the idle task - print a warning
34 * message if some code attempts to do it:
35 */
36static void
37dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
38{
39 raw_spin_unlock_irq(&rq->lock);
40 printk(KERN_ERR "bad: scheduling from the idle thread!\n");
41 dump_stack();
42 raw_spin_lock_irq(&rq->lock);
43}
44
45static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
46{
47}
48
49static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
50{
51}
52
53static void set_curr_task_idle(struct rq *rq)
54{
55}
56
57static void switched_to_idle(struct rq *rq, struct task_struct *p)
58{
59 BUG();
60}
61
62static void
63prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
64{
65 BUG();
66}
67
68static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
69{
70 return 0;
71}
72
73/*
74 * Simple, special scheduling class for the per-CPU idle tasks:
75 */
76const struct sched_class idle_sched_class = {
77 /* .next is NULL */
78 /* no enqueue/yield_task for idle tasks */
79
80 /* dequeue is not valid, we print a debug message there: */
81 .dequeue_task = dequeue_task_idle,
82
83 .check_preempt_curr = check_preempt_curr_idle,
84
85 .pick_next_task = pick_next_task_idle,
86 .put_prev_task = put_prev_task_idle,
87
88#ifdef CONFIG_SMP
89 .select_task_rq = select_task_rq_idle,
90#endif
91
92 .set_curr_task = set_curr_task_idle,
93 .task_tick = task_tick_idle,
94
95 .get_rr_interval = get_rr_interval_idle,
96
97 .prio_changed = prio_changed_idle,
98 .switched_to = switched_to_idle,
99};
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
new file mode 100644
index 000000000000..3640ebbb466b
--- /dev/null
+++ b/kernel/sched/rt.c
@@ -0,0 +1,2048 @@
1/*
2 * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
3 * policies)
4 */
5
6#include "sched.h"
7
8#include <linux/slab.h>
9
10static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
11
12struct rt_bandwidth def_rt_bandwidth;
13
14static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
15{
16 struct rt_bandwidth *rt_b =
17 container_of(timer, struct rt_bandwidth, rt_period_timer);
18 ktime_t now;
19 int overrun;
20 int idle = 0;
21
22 for (;;) {
23 now = hrtimer_cb_get_time(timer);
24 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
25
26 if (!overrun)
27 break;
28
29 idle = do_sched_rt_period_timer(rt_b, overrun);
30 }
31
32 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
33}
34
35void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
36{
37 rt_b->rt_period = ns_to_ktime(period);
38 rt_b->rt_runtime = runtime;
39
40 raw_spin_lock_init(&rt_b->rt_runtime_lock);
41
42 hrtimer_init(&rt_b->rt_period_timer,
43 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
44 rt_b->rt_period_timer.function = sched_rt_period_timer;
45}
46
47static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
48{
49 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
50 return;
51
52 if (hrtimer_active(&rt_b->rt_period_timer))
53 return;
54
55 raw_spin_lock(&rt_b->rt_runtime_lock);
56 start_bandwidth_timer(&rt_b->rt_period_timer, rt_b->rt_period);
57 raw_spin_unlock(&rt_b->rt_runtime_lock);
58}
59
60void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
61{
62 struct rt_prio_array *array;
63 int i;
64
65 array = &rt_rq->active;
66 for (i = 0; i < MAX_RT_PRIO; i++) {
67 INIT_LIST_HEAD(array->queue + i);
68 __clear_bit(i, array->bitmap);
69 }
70 /* delimiter for bitsearch: */
71 __set_bit(MAX_RT_PRIO, array->bitmap);
72
73#if defined CONFIG_SMP
74 rt_rq->highest_prio.curr = MAX_RT_PRIO;
75 rt_rq->highest_prio.next = MAX_RT_PRIO;
76 rt_rq->rt_nr_migratory = 0;
77 rt_rq->overloaded = 0;
78 plist_head_init(&rt_rq->pushable_tasks);
79#endif
80
81 rt_rq->rt_time = 0;
82 rt_rq->rt_throttled = 0;
83 rt_rq->rt_runtime = 0;
84 raw_spin_lock_init(&rt_rq->rt_runtime_lock);
85}
86
87#ifdef CONFIG_RT_GROUP_SCHED
88static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
89{
90 hrtimer_cancel(&rt_b->rt_period_timer);
91}
92
93#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
94
95static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
96{
97#ifdef CONFIG_SCHED_DEBUG
98 WARN_ON_ONCE(!rt_entity_is_task(rt_se));
99#endif
100 return container_of(rt_se, struct task_struct, rt);
101}
102
103static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
104{
105 return rt_rq->rq;
106}
107
108static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
109{
110 return rt_se->rt_rq;
111}
112
113void free_rt_sched_group(struct task_group *tg)
114{
115 int i;
116
117 if (tg->rt_se)
118 destroy_rt_bandwidth(&tg->rt_bandwidth);
119
120 for_each_possible_cpu(i) {
121 if (tg->rt_rq)
122 kfree(tg->rt_rq[i]);
123 if (tg->rt_se)
124 kfree(tg->rt_se[i]);
125 }
126
127 kfree(tg->rt_rq);
128 kfree(tg->rt_se);
129}
130
131void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
132 struct sched_rt_entity *rt_se, int cpu,
133 struct sched_rt_entity *parent)
134{
135 struct rq *rq = cpu_rq(cpu);
136
137 rt_rq->highest_prio.curr = MAX_RT_PRIO;
138 rt_rq->rt_nr_boosted = 0;
139 rt_rq->rq = rq;
140 rt_rq->tg = tg;
141
142 tg->rt_rq[cpu] = rt_rq;
143 tg->rt_se[cpu] = rt_se;
144
145 if (!rt_se)
146 return;
147
148 if (!parent)
149 rt_se->rt_rq = &rq->rt;
150 else
151 rt_se->rt_rq = parent->my_q;
152
153 rt_se->my_q = rt_rq;
154 rt_se->parent = parent;
155 INIT_LIST_HEAD(&rt_se->run_list);
156}
157
158int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
159{
160 struct rt_rq *rt_rq;
161 struct sched_rt_entity *rt_se;
162 int i;
163
164 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
165 if (!tg->rt_rq)
166 goto err;
167 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
168 if (!tg->rt_se)
169 goto err;
170
171 init_rt_bandwidth(&tg->rt_bandwidth,
172 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
173
174 for_each_possible_cpu(i) {
175 rt_rq = kzalloc_node(sizeof(struct rt_rq),
176 GFP_KERNEL, cpu_to_node(i));
177 if (!rt_rq)
178 goto err;
179
180 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
181 GFP_KERNEL, cpu_to_node(i));
182 if (!rt_se)
183 goto err_free_rq;
184
185 init_rt_rq(rt_rq, cpu_rq(i));
186 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
187 init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
188 }
189
190 return 1;
191
192err_free_rq:
193 kfree(rt_rq);
194err:
195 return 0;
196}
197
198#else /* CONFIG_RT_GROUP_SCHED */
199
200#define rt_entity_is_task(rt_se) (1)
201
202static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
203{
204 return container_of(rt_se, struct task_struct, rt);
205}
206
207static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
208{
209 return container_of(rt_rq, struct rq, rt);
210}
211
212static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
213{
214 struct task_struct *p = rt_task_of(rt_se);
215 struct rq *rq = task_rq(p);
216
217 return &rq->rt;
218}
219
220void free_rt_sched_group(struct task_group *tg) { }
221
222int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
223{
224 return 1;
225}
226#endif /* CONFIG_RT_GROUP_SCHED */
227
228#ifdef CONFIG_SMP
229
230static inline int rt_overloaded(struct rq *rq)
231{
232 return atomic_read(&rq->rd->rto_count);
233}
234
235static inline void rt_set_overload(struct rq *rq)
236{
237 if (!rq->online)
238 return;
239
240 cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
241 /*
242 * Make sure the mask is visible before we set
243 * the overload count. That is checked to determine
244 * if we should look at the mask. It would be a shame
245 * if we looked at the mask, but the mask was not
246 * updated yet.
247 */
248 wmb();
249 atomic_inc(&rq->rd->rto_count);
250}
251
252static inline void rt_clear_overload(struct rq *rq)
253{
254 if (!rq->online)
255 return;
256
257 /* the order here really doesn't matter */
258 atomic_dec(&rq->rd->rto_count);
259 cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
260}
261
262static void update_rt_migration(struct rt_rq *rt_rq)
263{
264 if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
265 if (!rt_rq->overloaded) {
266 rt_set_overload(rq_of_rt_rq(rt_rq));
267 rt_rq->overloaded = 1;
268 }
269 } else if (rt_rq->overloaded) {
270 rt_clear_overload(rq_of_rt_rq(rt_rq));
271 rt_rq->overloaded = 0;
272 }
273}
274
275static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
276{
277 if (!rt_entity_is_task(rt_se))
278 return;
279
280 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
281
282 rt_rq->rt_nr_total++;
283 if (rt_se->nr_cpus_allowed > 1)
284 rt_rq->rt_nr_migratory++;
285
286 update_rt_migration(rt_rq);
287}
288
289static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
290{
291 if (!rt_entity_is_task(rt_se))
292 return;
293
294 rt_rq = &rq_of_rt_rq(rt_rq)->rt;
295
296 rt_rq->rt_nr_total--;
297 if (rt_se->nr_cpus_allowed > 1)
298 rt_rq->rt_nr_migratory--;
299
300 update_rt_migration(rt_rq);
301}
302
303static inline int has_pushable_tasks(struct rq *rq)
304{
305 return !plist_head_empty(&rq->rt.pushable_tasks);
306}
307
308static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
309{
310 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
311 plist_node_init(&p->pushable_tasks, p->prio);
312 plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
313
314 /* Update the highest prio pushable task */
315 if (p->prio < rq->rt.highest_prio.next)
316 rq->rt.highest_prio.next = p->prio;
317}
318
319static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
320{
321 plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
322
323 /* Update the new highest prio pushable task */
324 if (has_pushable_tasks(rq)) {
325 p = plist_first_entry(&rq->rt.pushable_tasks,
326 struct task_struct, pushable_tasks);
327 rq->rt.highest_prio.next = p->prio;
328 } else
329 rq->rt.highest_prio.next = MAX_RT_PRIO;
330}
331
332#else
333
334static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
335{
336}
337
338static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
339{
340}
341
342static inline
343void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
344{
345}
346
347static inline
348void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
349{
350}
351
352#endif /* CONFIG_SMP */
353
354static inline int on_rt_rq(struct sched_rt_entity *rt_se)
355{
356 return !list_empty(&rt_se->run_list);
357}
358
359#ifdef CONFIG_RT_GROUP_SCHED
360
361static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
362{
363 if (!rt_rq->tg)
364 return RUNTIME_INF;
365
366 return rt_rq->rt_runtime;
367}
368
369static inline u64 sched_rt_period(struct rt_rq *rt_rq)
370{
371 return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
372}
373
374typedef struct task_group *rt_rq_iter_t;
375
376static inline struct task_group *next_task_group(struct task_group *tg)
377{
378 do {
379 tg = list_entry_rcu(tg->list.next,
380 typeof(struct task_group), list);
381 } while (&tg->list != &task_groups && task_group_is_autogroup(tg));
382
383 if (&tg->list == &task_groups)
384 tg = NULL;
385
386 return tg;
387}
388
389#define for_each_rt_rq(rt_rq, iter, rq) \
390 for (iter = container_of(&task_groups, typeof(*iter), list); \
391 (iter = next_task_group(iter)) && \
392 (rt_rq = iter->rt_rq[cpu_of(rq)]);)
393
394static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
395{
396 list_add_rcu(&rt_rq->leaf_rt_rq_list,
397 &rq_of_rt_rq(rt_rq)->leaf_rt_rq_list);
398}
399
400static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
401{
402 list_del_rcu(&rt_rq->leaf_rt_rq_list);
403}
404
405#define for_each_leaf_rt_rq(rt_rq, rq) \
406 list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
407
408#define for_each_sched_rt_entity(rt_se) \
409 for (; rt_se; rt_se = rt_se->parent)
410
411static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
412{
413 return rt_se->my_q;
414}
415
416static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head);
417static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
418
419static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
420{
421 struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
422 struct sched_rt_entity *rt_se;
423
424 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
425
426 rt_se = rt_rq->tg->rt_se[cpu];
427
428 if (rt_rq->rt_nr_running) {
429 if (rt_se && !on_rt_rq(rt_se))
430 enqueue_rt_entity(rt_se, false);
431 if (rt_rq->highest_prio.curr < curr->prio)
432 resched_task(curr);
433 }
434}
435
436static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
437{
438 struct sched_rt_entity *rt_se;
439 int cpu = cpu_of(rq_of_rt_rq(rt_rq));
440
441 rt_se = rt_rq->tg->rt_se[cpu];
442
443 if (rt_se && on_rt_rq(rt_se))
444 dequeue_rt_entity(rt_se);
445}
446
447static inline int rt_rq_throttled(struct rt_rq *rt_rq)
448{
449 return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
450}
451
452static int rt_se_boosted(struct sched_rt_entity *rt_se)
453{
454 struct rt_rq *rt_rq = group_rt_rq(rt_se);
455 struct task_struct *p;
456
457 if (rt_rq)
458 return !!rt_rq->rt_nr_boosted;
459
460 p = rt_task_of(rt_se);
461 return p->prio != p->normal_prio;
462}
463
464#ifdef CONFIG_SMP
465static inline const struct cpumask *sched_rt_period_mask(void)
466{
467 return cpu_rq(smp_processor_id())->rd->span;
468}
469#else
470static inline const struct cpumask *sched_rt_period_mask(void)
471{
472 return cpu_online_mask;
473}
474#endif
475
476static inline
477struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
478{
479 return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
480}
481
482static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
483{
484 return &rt_rq->tg->rt_bandwidth;
485}
486
487#else /* !CONFIG_RT_GROUP_SCHED */
488
489static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
490{
491 return rt_rq->rt_runtime;
492}
493
494static inline u64 sched_rt_period(struct rt_rq *rt_rq)
495{
496 return ktime_to_ns(def_rt_bandwidth.rt_period);
497}
498
499typedef struct rt_rq *rt_rq_iter_t;
500
501#define for_each_rt_rq(rt_rq, iter, rq) \
502 for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
503
504static inline void list_add_leaf_rt_rq(struct rt_rq *rt_rq)
505{
506}
507
508static inline void list_del_leaf_rt_rq(struct rt_rq *rt_rq)
509{
510}
511
512#define for_each_leaf_rt_rq(rt_rq, rq) \
513 for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
514
515#define for_each_sched_rt_entity(rt_se) \
516 for (; rt_se; rt_se = NULL)
517
518static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
519{
520 return NULL;
521}
522
523static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
524{
525 if (rt_rq->rt_nr_running)
526 resched_task(rq_of_rt_rq(rt_rq)->curr);
527}
528
529static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
530{
531}
532
533static inline int rt_rq_throttled(struct rt_rq *rt_rq)
534{
535 return rt_rq->rt_throttled;
536}
537
538static inline const struct cpumask *sched_rt_period_mask(void)
539{
540 return cpu_online_mask;
541}
542
543static inline
544struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
545{
546 return &cpu_rq(cpu)->rt;
547}
548
549static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
550{
551 return &def_rt_bandwidth;
552}
553
554#endif /* CONFIG_RT_GROUP_SCHED */
555
556#ifdef CONFIG_SMP
557/*
558 * We ran out of runtime, see if we can borrow some from our neighbours.
559 */
560static int do_balance_runtime(struct rt_rq *rt_rq)
561{
562 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
563 struct root_domain *rd = cpu_rq(smp_processor_id())->rd;
564 int i, weight, more = 0;
565 u64 rt_period;
566
567 weight = cpumask_weight(rd->span);
568
569 raw_spin_lock(&rt_b->rt_runtime_lock);
570 rt_period = ktime_to_ns(rt_b->rt_period);
571 for_each_cpu(i, rd->span) {
572 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
573 s64 diff;
574
575 if (iter == rt_rq)
576 continue;
577
578 raw_spin_lock(&iter->rt_runtime_lock);
579 /*
580 * Either all rqs have inf runtime and there's nothing to steal
581 * or __disable_runtime() below sets a specific rq to inf to
582 * indicate its been disabled and disalow stealing.
583 */
584 if (iter->rt_runtime == RUNTIME_INF)
585 goto next;
586
587 /*
588 * From runqueues with spare time, take 1/n part of their
589 * spare time, but no more than our period.
590 */
591 diff = iter->rt_runtime - iter->rt_time;
592 if (diff > 0) {
593 diff = div_u64((u64)diff, weight);
594 if (rt_rq->rt_runtime + diff > rt_period)
595 diff = rt_period - rt_rq->rt_runtime;
596 iter->rt_runtime -= diff;
597 rt_rq->rt_runtime += diff;
598 more = 1;
599 if (rt_rq->rt_runtime == rt_period) {
600 raw_spin_unlock(&iter->rt_runtime_lock);
601 break;
602 }
603 }
604next:
605 raw_spin_unlock(&iter->rt_runtime_lock);
606 }
607 raw_spin_unlock(&rt_b->rt_runtime_lock);
608
609 return more;
610}
611
612/*
613 * Ensure this RQ takes back all the runtime it lend to its neighbours.
614 */
615static void __disable_runtime(struct rq *rq)
616{
617 struct root_domain *rd = rq->rd;
618 rt_rq_iter_t iter;
619 struct rt_rq *rt_rq;
620
621 if (unlikely(!scheduler_running))
622 return;
623
624 for_each_rt_rq(rt_rq, iter, rq) {
625 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
626 s64 want;
627 int i;
628
629 raw_spin_lock(&rt_b->rt_runtime_lock);
630 raw_spin_lock(&rt_rq->rt_runtime_lock);
631 /*
632 * Either we're all inf and nobody needs to borrow, or we're
633 * already disabled and thus have nothing to do, or we have
634 * exactly the right amount of runtime to take out.
635 */
636 if (rt_rq->rt_runtime == RUNTIME_INF ||
637 rt_rq->rt_runtime == rt_b->rt_runtime)
638 goto balanced;
639 raw_spin_unlock(&rt_rq->rt_runtime_lock);
640
641 /*
642 * Calculate the difference between what we started out with
643 * and what we current have, that's the amount of runtime
644 * we lend and now have to reclaim.
645 */
646 want = rt_b->rt_runtime - rt_rq->rt_runtime;
647
648 /*
649 * Greedy reclaim, take back as much as we can.
650 */
651 for_each_cpu(i, rd->span) {
652 struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
653 s64 diff;
654
655 /*
656 * Can't reclaim from ourselves or disabled runqueues.
657 */
658 if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
659 continue;
660
661 raw_spin_lock(&iter->rt_runtime_lock);
662 if (want > 0) {
663 diff = min_t(s64, iter->rt_runtime, want);
664 iter->rt_runtime -= diff;
665 want -= diff;
666 } else {
667 iter->rt_runtime -= want;
668 want -= want;
669 }
670 raw_spin_unlock(&iter->rt_runtime_lock);
671
672 if (!want)
673 break;
674 }
675
676 raw_spin_lock(&rt_rq->rt_runtime_lock);
677 /*
678 * We cannot be left wanting - that would mean some runtime
679 * leaked out of the system.
680 */
681 BUG_ON(want);
682balanced:
683 /*
684 * Disable all the borrow logic by pretending we have inf
685 * runtime - in which case borrowing doesn't make sense.
686 */
687 rt_rq->rt_runtime = RUNTIME_INF;
688 raw_spin_unlock(&rt_rq->rt_runtime_lock);
689 raw_spin_unlock(&rt_b->rt_runtime_lock);
690 }
691}
692
693static void disable_runtime(struct rq *rq)
694{
695 unsigned long flags;
696
697 raw_spin_lock_irqsave(&rq->lock, flags);
698 __disable_runtime(rq);
699 raw_spin_unlock_irqrestore(&rq->lock, flags);
700}
701
702static void __enable_runtime(struct rq *rq)
703{
704 rt_rq_iter_t iter;
705 struct rt_rq *rt_rq;
706
707 if (unlikely(!scheduler_running))
708 return;
709
710 /*
711 * Reset each runqueue's bandwidth settings
712 */
713 for_each_rt_rq(rt_rq, iter, rq) {
714 struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
715
716 raw_spin_lock(&rt_b->rt_runtime_lock);
717 raw_spin_lock(&rt_rq->rt_runtime_lock);
718 rt_rq->rt_runtime = rt_b->rt_runtime;
719 rt_rq->rt_time = 0;
720 rt_rq->rt_throttled = 0;
721 raw_spin_unlock(&rt_rq->rt_runtime_lock);
722 raw_spin_unlock(&rt_b->rt_runtime_lock);
723 }
724}
725
726static void enable_runtime(struct rq *rq)
727{
728 unsigned long flags;
729
730 raw_spin_lock_irqsave(&rq->lock, flags);
731 __enable_runtime(rq);
732 raw_spin_unlock_irqrestore(&rq->lock, flags);
733}
734
735int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
736{
737 int cpu = (int)(long)hcpu;
738
739 switch (action) {
740 case CPU_DOWN_PREPARE:
741 case CPU_DOWN_PREPARE_FROZEN:
742 disable_runtime(cpu_rq(cpu));
743 return NOTIFY_OK;
744
745 case CPU_DOWN_FAILED:
746 case CPU_DOWN_FAILED_FROZEN:
747 case CPU_ONLINE:
748 case CPU_ONLINE_FROZEN:
749 enable_runtime(cpu_rq(cpu));
750 return NOTIFY_OK;
751
752 default:
753 return NOTIFY_DONE;
754 }
755}
756
757static int balance_runtime(struct rt_rq *rt_rq)
758{
759 int more = 0;
760
761 if (!sched_feat(RT_RUNTIME_SHARE))
762 return more;
763
764 if (rt_rq->rt_time > rt_rq->rt_runtime) {
765 raw_spin_unlock(&rt_rq->rt_runtime_lock);
766 more = do_balance_runtime(rt_rq);
767 raw_spin_lock(&rt_rq->rt_runtime_lock);
768 }
769
770 return more;
771}
772#else /* !CONFIG_SMP */
773static inline int balance_runtime(struct rt_rq *rt_rq)
774{
775 return 0;
776}
777#endif /* CONFIG_SMP */
778
779static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
780{
781 int i, idle = 1;
782 const struct cpumask *span;
783
784 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
785 return 1;
786
787 span = sched_rt_period_mask();
788 for_each_cpu(i, span) {
789 int enqueue = 0;
790 struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
791 struct rq *rq = rq_of_rt_rq(rt_rq);
792
793 raw_spin_lock(&rq->lock);
794 if (rt_rq->rt_time) {
795 u64 runtime;
796
797 raw_spin_lock(&rt_rq->rt_runtime_lock);
798 if (rt_rq->rt_throttled)
799 balance_runtime(rt_rq);
800 runtime = rt_rq->rt_runtime;
801 rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
802 if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
803 rt_rq->rt_throttled = 0;
804 enqueue = 1;
805
806 /*
807 * Force a clock update if the CPU was idle,
808 * lest wakeup -> unthrottle time accumulate.
809 */
810 if (rt_rq->rt_nr_running && rq->curr == rq->idle)
811 rq->skip_clock_update = -1;
812 }
813 if (rt_rq->rt_time || rt_rq->rt_nr_running)
814 idle = 0;
815 raw_spin_unlock(&rt_rq->rt_runtime_lock);
816 } else if (rt_rq->rt_nr_running) {
817 idle = 0;
818 if (!rt_rq_throttled(rt_rq))
819 enqueue = 1;
820 }
821
822 if (enqueue)
823 sched_rt_rq_enqueue(rt_rq);
824 raw_spin_unlock(&rq->lock);
825 }
826
827 return idle;
828}
829
830static inline int rt_se_prio(struct sched_rt_entity *rt_se)
831{
832#ifdef CONFIG_RT_GROUP_SCHED
833 struct rt_rq *rt_rq = group_rt_rq(rt_se);
834
835 if (rt_rq)
836 return rt_rq->highest_prio.curr;
837#endif
838
839 return rt_task_of(rt_se)->prio;
840}
841
842static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
843{
844 u64 runtime = sched_rt_runtime(rt_rq);
845
846 if (rt_rq->rt_throttled)
847 return rt_rq_throttled(rt_rq);
848
849 if (runtime >= sched_rt_period(rt_rq))
850 return 0;
851
852 balance_runtime(rt_rq);
853 runtime = sched_rt_runtime(rt_rq);
854 if (runtime == RUNTIME_INF)
855 return 0;
856
857 if (rt_rq->rt_time > runtime) {
858 rt_rq->rt_throttled = 1;
859 printk_once(KERN_WARNING "sched: RT throttling activated\n");
860 if (rt_rq_throttled(rt_rq)) {
861 sched_rt_rq_dequeue(rt_rq);
862 return 1;
863 }
864 }
865
866 return 0;
867}
868
869/*
870 * Update the current task's runtime statistics. Skip current tasks that
871 * are not in our scheduling class.
872 */
873static void update_curr_rt(struct rq *rq)
874{
875 struct task_struct *curr = rq->curr;
876 struct sched_rt_entity *rt_se = &curr->rt;
877 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
878 u64 delta_exec;
879
880 if (curr->sched_class != &rt_sched_class)
881 return;
882
883 delta_exec = rq->clock_task - curr->se.exec_start;
884 if (unlikely((s64)delta_exec < 0))
885 delta_exec = 0;
886
887 schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec));
888
889 curr->se.sum_exec_runtime += delta_exec;
890 account_group_exec_runtime(curr, delta_exec);
891
892 curr->se.exec_start = rq->clock_task;
893 cpuacct_charge(curr, delta_exec);
894
895 sched_rt_avg_update(rq, delta_exec);
896
897 if (!rt_bandwidth_enabled())
898 return;
899
900 for_each_sched_rt_entity(rt_se) {
901 rt_rq = rt_rq_of_se(rt_se);
902
903 if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
904 raw_spin_lock(&rt_rq->rt_runtime_lock);
905 rt_rq->rt_time += delta_exec;
906 if (sched_rt_runtime_exceeded(rt_rq))
907 resched_task(curr);
908 raw_spin_unlock(&rt_rq->rt_runtime_lock);
909 }
910 }
911}
912
913#if defined CONFIG_SMP
914
915static void
916inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
917{
918 struct rq *rq = rq_of_rt_rq(rt_rq);
919
920 if (rq->online && prio < prev_prio)
921 cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
922}
923
924static void
925dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
926{
927 struct rq *rq = rq_of_rt_rq(rt_rq);
928
929 if (rq->online && rt_rq->highest_prio.curr != prev_prio)
930 cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
931}
932
933#else /* CONFIG_SMP */
934
935static inline
936void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
937static inline
938void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
939
940#endif /* CONFIG_SMP */
941
942#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
943static void
944inc_rt_prio(struct rt_rq *rt_rq, int prio)
945{
946 int prev_prio = rt_rq->highest_prio.curr;
947
948 if (prio < prev_prio)
949 rt_rq->highest_prio.curr = prio;
950
951 inc_rt_prio_smp(rt_rq, prio, prev_prio);
952}
953
954static void
955dec_rt_prio(struct rt_rq *rt_rq, int prio)
956{
957 int prev_prio = rt_rq->highest_prio.curr;
958
959 if (rt_rq->rt_nr_running) {
960
961 WARN_ON(prio < prev_prio);
962
963 /*
964 * This may have been our highest task, and therefore
965 * we may have some recomputation to do
966 */
967 if (prio == prev_prio) {
968 struct rt_prio_array *array = &rt_rq->active;
969
970 rt_rq->highest_prio.curr =
971 sched_find_first_bit(array->bitmap);
972 }
973
974 } else
975 rt_rq->highest_prio.curr = MAX_RT_PRIO;
976
977 dec_rt_prio_smp(rt_rq, prio, prev_prio);
978}
979
980#else
981
982static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
983static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
984
985#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
986
987#ifdef CONFIG_RT_GROUP_SCHED
988
989static void
990inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
991{
992 if (rt_se_boosted(rt_se))
993 rt_rq->rt_nr_boosted++;
994
995 if (rt_rq->tg)
996 start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
997}
998
999static void
1000dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1001{
1002 if (rt_se_boosted(rt_se))
1003 rt_rq->rt_nr_boosted--;
1004
1005 WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
1006}
1007
1008#else /* CONFIG_RT_GROUP_SCHED */
1009
1010static void
1011inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1012{
1013 start_rt_bandwidth(&def_rt_bandwidth);
1014}
1015
1016static inline
1017void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
1018
1019#endif /* CONFIG_RT_GROUP_SCHED */
1020
1021static inline
1022void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1023{
1024 int prio = rt_se_prio(rt_se);
1025
1026 WARN_ON(!rt_prio(prio));
1027 rt_rq->rt_nr_running++;
1028
1029 inc_rt_prio(rt_rq, prio);
1030 inc_rt_migration(rt_se, rt_rq);
1031 inc_rt_group(rt_se, rt_rq);
1032}
1033
1034static inline
1035void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
1036{
1037 WARN_ON(!rt_prio(rt_se_prio(rt_se)));
1038 WARN_ON(!rt_rq->rt_nr_running);
1039 rt_rq->rt_nr_running--;
1040
1041 dec_rt_prio(rt_rq, rt_se_prio(rt_se));
1042 dec_rt_migration(rt_se, rt_rq);
1043 dec_rt_group(rt_se, rt_rq);
1044}
1045
1046static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1047{
1048 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1049 struct rt_prio_array *array = &rt_rq->active;
1050 struct rt_rq *group_rq = group_rt_rq(rt_se);
1051 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1052
1053 /*
1054 * Don't enqueue the group if its throttled, or when empty.
1055 * The latter is a consequence of the former when a child group
1056 * get throttled and the current group doesn't have any other
1057 * active members.
1058 */
1059 if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
1060 return;
1061
1062 if (!rt_rq->rt_nr_running)
1063 list_add_leaf_rt_rq(rt_rq);
1064
1065 if (head)
1066 list_add(&rt_se->run_list, queue);
1067 else
1068 list_add_tail(&rt_se->run_list, queue);
1069 __set_bit(rt_se_prio(rt_se), array->bitmap);
1070
1071 inc_rt_tasks(rt_se, rt_rq);
1072}
1073
1074static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
1075{
1076 struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
1077 struct rt_prio_array *array = &rt_rq->active;
1078
1079 list_del_init(&rt_se->run_list);
1080 if (list_empty(array->queue + rt_se_prio(rt_se)))
1081 __clear_bit(rt_se_prio(rt_se), array->bitmap);
1082
1083 dec_rt_tasks(rt_se, rt_rq);
1084 if (!rt_rq->rt_nr_running)
1085 list_del_leaf_rt_rq(rt_rq);
1086}
1087
1088/*
1089 * Because the prio of an upper entry depends on the lower
1090 * entries, we must remove entries top - down.
1091 */
1092static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
1093{
1094 struct sched_rt_entity *back = NULL;
1095
1096 for_each_sched_rt_entity(rt_se) {
1097 rt_se->back = back;
1098 back = rt_se;
1099 }
1100
1101 for (rt_se = back; rt_se; rt_se = rt_se->back) {
1102 if (on_rt_rq(rt_se))
1103 __dequeue_rt_entity(rt_se);
1104 }
1105}
1106
1107static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head)
1108{
1109 dequeue_rt_stack(rt_se);
1110 for_each_sched_rt_entity(rt_se)
1111 __enqueue_rt_entity(rt_se, head);
1112}
1113
1114static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
1115{
1116 dequeue_rt_stack(rt_se);
1117
1118 for_each_sched_rt_entity(rt_se) {
1119 struct rt_rq *rt_rq = group_rt_rq(rt_se);
1120
1121 if (rt_rq && rt_rq->rt_nr_running)
1122 __enqueue_rt_entity(rt_se, false);
1123 }
1124}
1125
1126/*
1127 * Adding/removing a task to/from a priority array:
1128 */
1129static void
1130enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1131{
1132 struct sched_rt_entity *rt_se = &p->rt;
1133
1134 if (flags & ENQUEUE_WAKEUP)
1135 rt_se->timeout = 0;
1136
1137 enqueue_rt_entity(rt_se, flags & ENQUEUE_HEAD);
1138
1139 if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
1140 enqueue_pushable_task(rq, p);
1141
1142 inc_nr_running(rq);
1143}
1144
1145static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
1146{
1147 struct sched_rt_entity *rt_se = &p->rt;
1148
1149 update_curr_rt(rq);
1150 dequeue_rt_entity(rt_se);
1151
1152 dequeue_pushable_task(rq, p);
1153
1154 dec_nr_running(rq);
1155}
1156
1157/*
1158 * Put task to the head or the end of the run list without the overhead of
1159 * dequeue followed by enqueue.
1160 */
1161static void
1162requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
1163{
1164 if (on_rt_rq(rt_se)) {
1165 struct rt_prio_array *array = &rt_rq->active;
1166 struct list_head *queue = array->queue + rt_se_prio(rt_se);
1167
1168 if (head)
1169 list_move(&rt_se->run_list, queue);
1170 else
1171 list_move_tail(&rt_se->run_list, queue);
1172 }
1173}
1174
1175static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
1176{
1177 struct sched_rt_entity *rt_se = &p->rt;
1178 struct rt_rq *rt_rq;
1179
1180 for_each_sched_rt_entity(rt_se) {
1181 rt_rq = rt_rq_of_se(rt_se);
1182 requeue_rt_entity(rt_rq, rt_se, head);
1183 }
1184}
1185
1186static void yield_task_rt(struct rq *rq)
1187{
1188 requeue_task_rt(rq, rq->curr, 0);
1189}
1190
1191#ifdef CONFIG_SMP
1192static int find_lowest_rq(struct task_struct *task);
1193
1194static int
1195select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
1196{
1197 struct task_struct *curr;
1198 struct rq *rq;
1199 int cpu;
1200
1201 cpu = task_cpu(p);
1202
1203 if (p->rt.nr_cpus_allowed == 1)
1204 goto out;
1205
1206 /* For anything but wake ups, just return the task_cpu */
1207 if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
1208 goto out;
1209
1210 rq = cpu_rq(cpu);
1211
1212 rcu_read_lock();
1213 curr = ACCESS_ONCE(rq->curr); /* unlocked access */
1214
1215 /*
1216 * If the current task on @p's runqueue is an RT task, then
1217 * try to see if we can wake this RT task up on another
1218 * runqueue. Otherwise simply start this RT task
1219 * on its current runqueue.
1220 *
1221 * We want to avoid overloading runqueues. If the woken
1222 * task is a higher priority, then it will stay on this CPU
1223 * and the lower prio task should be moved to another CPU.
1224 * Even though this will probably make the lower prio task
1225 * lose its cache, we do not want to bounce a higher task
1226 * around just because it gave up its CPU, perhaps for a
1227 * lock?
1228 *
1229 * For equal prio tasks, we just let the scheduler sort it out.
1230 *
1231 * Otherwise, just let it ride on the affined RQ and the
1232 * post-schedule router will push the preempted task away
1233 *
1234 * This test is optimistic, if we get it wrong the load-balancer
1235 * will have to sort it out.
1236 */
1237 if (curr && unlikely(rt_task(curr)) &&
1238 (curr->rt.nr_cpus_allowed < 2 ||
1239 curr->prio <= p->prio) &&
1240 (p->rt.nr_cpus_allowed > 1)) {
1241 int target = find_lowest_rq(p);
1242
1243 if (target != -1)
1244 cpu = target;
1245 }
1246 rcu_read_unlock();
1247
1248out:
1249 return cpu;
1250}
1251
1252static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
1253{
1254 if (rq->curr->rt.nr_cpus_allowed == 1)
1255 return;
1256
1257 if (p->rt.nr_cpus_allowed != 1
1258 && cpupri_find(&rq->rd->cpupri, p, NULL))
1259 return;
1260
1261 if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
1262 return;
1263
1264 /*
1265 * There appears to be other cpus that can accept
1266 * current and none to run 'p', so lets reschedule
1267 * to try and push current away:
1268 */
1269 requeue_task_rt(rq, p, 1);
1270 resched_task(rq->curr);
1271}
1272
1273#endif /* CONFIG_SMP */
1274
1275/*
1276 * Preempt the current task with a newly woken task if needed:
1277 */
1278static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
1279{
1280 if (p->prio < rq->curr->prio) {
1281 resched_task(rq->curr);
1282 return;
1283 }
1284
1285#ifdef CONFIG_SMP
1286 /*
1287 * If:
1288 *
1289 * - the newly woken task is of equal priority to the current task
1290 * - the newly woken task is non-migratable while current is migratable
1291 * - current will be preempted on the next reschedule
1292 *
1293 * we should check to see if current can readily move to a different
1294 * cpu. If so, we will reschedule to allow the push logic to try
1295 * to move current somewhere else, making room for our non-migratable
1296 * task.
1297 */
1298 if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
1299 check_preempt_equal_prio(rq, p);
1300#endif
1301}
1302
1303static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
1304 struct rt_rq *rt_rq)
1305{
1306 struct rt_prio_array *array = &rt_rq->active;
1307 struct sched_rt_entity *next = NULL;
1308 struct list_head *queue;
1309 int idx;
1310
1311 idx = sched_find_first_bit(array->bitmap);
1312 BUG_ON(idx >= MAX_RT_PRIO);
1313
1314 queue = array->queue + idx;
1315 next = list_entry(queue->next, struct sched_rt_entity, run_list);
1316
1317 return next;
1318}
1319
1320static struct task_struct *_pick_next_task_rt(struct rq *rq)
1321{
1322 struct sched_rt_entity *rt_se;
1323 struct task_struct *p;
1324 struct rt_rq *rt_rq;
1325
1326 rt_rq = &rq->rt;
1327
1328 if (!rt_rq->rt_nr_running)
1329 return NULL;
1330
1331 if (rt_rq_throttled(rt_rq))
1332 return NULL;
1333
1334 do {
1335 rt_se = pick_next_rt_entity(rq, rt_rq);
1336 BUG_ON(!rt_se);
1337 rt_rq = group_rt_rq(rt_se);
1338 } while (rt_rq);
1339
1340 p = rt_task_of(rt_se);
1341 p->se.exec_start = rq->clock_task;
1342
1343 return p;
1344}
1345
1346static struct task_struct *pick_next_task_rt(struct rq *rq)
1347{
1348 struct task_struct *p = _pick_next_task_rt(rq);
1349
1350 /* The running task is never eligible for pushing */
1351 if (p)
1352 dequeue_pushable_task(rq, p);
1353
1354#ifdef CONFIG_SMP
1355 /*
1356 * We detect this state here so that we can avoid taking the RQ
1357 * lock again later if there is no need to push
1358 */
1359 rq->post_schedule = has_pushable_tasks(rq);
1360#endif
1361
1362 return p;
1363}
1364
1365static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
1366{
1367 update_curr_rt(rq);
1368
1369 /*
1370 * The previous task needs to be made eligible for pushing
1371 * if it is still active
1372 */
1373 if (on_rt_rq(&p->rt) && p->rt.nr_cpus_allowed > 1)
1374 enqueue_pushable_task(rq, p);
1375}
1376
1377#ifdef CONFIG_SMP
1378
1379/* Only try algorithms three times */
1380#define RT_MAX_TRIES 3
1381
1382static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
1383{
1384 if (!task_running(rq, p) &&
1385 (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
1386 (p->rt.nr_cpus_allowed > 1))
1387 return 1;
1388 return 0;
1389}
1390
1391/* Return the second highest RT task, NULL otherwise */
1392static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
1393{
1394 struct task_struct *next = NULL;
1395 struct sched_rt_entity *rt_se;
1396 struct rt_prio_array *array;
1397 struct rt_rq *rt_rq;
1398 int idx;
1399
1400 for_each_leaf_rt_rq(rt_rq, rq) {
1401 array = &rt_rq->active;
1402 idx = sched_find_first_bit(array->bitmap);
1403next_idx:
1404 if (idx >= MAX_RT_PRIO)
1405 continue;
1406 if (next && next->prio < idx)
1407 continue;
1408 list_for_each_entry(rt_se, array->queue + idx, run_list) {
1409 struct task_struct *p;
1410
1411 if (!rt_entity_is_task(rt_se))
1412 continue;
1413
1414 p = rt_task_of(rt_se);
1415 if (pick_rt_task(rq, p, cpu)) {
1416 next = p;
1417 break;
1418 }
1419 }
1420 if (!next) {
1421 idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1);
1422 goto next_idx;
1423 }
1424 }
1425
1426 return next;
1427}
1428
1429static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
1430
1431static int find_lowest_rq(struct task_struct *task)
1432{
1433 struct sched_domain *sd;
1434 struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
1435 int this_cpu = smp_processor_id();
1436 int cpu = task_cpu(task);
1437
1438 /* Make sure the mask is initialized first */
1439 if (unlikely(!lowest_mask))
1440 return -1;
1441
1442 if (task->rt.nr_cpus_allowed == 1)
1443 return -1; /* No other targets possible */
1444
1445 if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
1446 return -1; /* No targets found */
1447
1448 /*
1449 * At this point we have built a mask of cpus representing the
1450 * lowest priority tasks in the system. Now we want to elect
1451 * the best one based on our affinity and topology.
1452 *
1453 * We prioritize the last cpu that the task executed on since
1454 * it is most likely cache-hot in that location.
1455 */
1456 if (cpumask_test_cpu(cpu, lowest_mask))
1457 return cpu;
1458
1459 /*
1460 * Otherwise, we consult the sched_domains span maps to figure
1461 * out which cpu is logically closest to our hot cache data.
1462 */
1463 if (!cpumask_test_cpu(this_cpu, lowest_mask))
1464 this_cpu = -1; /* Skip this_cpu opt if not among lowest */
1465
1466 rcu_read_lock();
1467 for_each_domain(cpu, sd) {
1468 if (sd->flags & SD_WAKE_AFFINE) {
1469 int best_cpu;
1470
1471 /*
1472 * "this_cpu" is cheaper to preempt than a
1473 * remote processor.
1474 */
1475 if (this_cpu != -1 &&
1476 cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
1477 rcu_read_unlock();
1478 return this_cpu;
1479 }
1480
1481 best_cpu = cpumask_first_and(lowest_mask,
1482 sched_domain_span(sd));
1483 if (best_cpu < nr_cpu_ids) {
1484 rcu_read_unlock();
1485 return best_cpu;
1486 }
1487 }
1488 }
1489 rcu_read_unlock();
1490
1491 /*
1492 * And finally, if there were no matches within the domains
1493 * just give the caller *something* to work with from the compatible
1494 * locations.
1495 */
1496 if (this_cpu != -1)
1497 return this_cpu;
1498
1499 cpu = cpumask_any(lowest_mask);
1500 if (cpu < nr_cpu_ids)
1501 return cpu;
1502 return -1;
1503}
1504
1505/* Will lock the rq it finds */
1506static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
1507{
1508 struct rq *lowest_rq = NULL;
1509 int tries;
1510 int cpu;
1511
1512 for (tries = 0; tries < RT_MAX_TRIES; tries++) {
1513 cpu = find_lowest_rq(task);
1514
1515 if ((cpu == -1) || (cpu == rq->cpu))
1516 break;
1517
1518 lowest_rq = cpu_rq(cpu);
1519
1520 /* if the prio of this runqueue changed, try again */
1521 if (double_lock_balance(rq, lowest_rq)) {
1522 /*
1523 * We had to unlock the run queue. In
1524 * the mean time, task could have
1525 * migrated already or had its affinity changed.
1526 * Also make sure that it wasn't scheduled on its rq.
1527 */
1528 if (unlikely(task_rq(task) != rq ||
1529 !cpumask_test_cpu(lowest_rq->cpu,
1530 tsk_cpus_allowed(task)) ||
1531 task_running(rq, task) ||
1532 !task->on_rq)) {
1533
1534 raw_spin_unlock(&lowest_rq->lock);
1535 lowest_rq = NULL;
1536 break;
1537 }
1538 }
1539
1540 /* If this rq is still suitable use it. */
1541 if (lowest_rq->rt.highest_prio.curr > task->prio)
1542 break;
1543
1544 /* try again */
1545 double_unlock_balance(rq, lowest_rq);
1546 lowest_rq = NULL;
1547 }
1548
1549 return lowest_rq;
1550}
1551
1552static struct task_struct *pick_next_pushable_task(struct rq *rq)
1553{
1554 struct task_struct *p;
1555
1556 if (!has_pushable_tasks(rq))
1557 return NULL;
1558
1559 p = plist_first_entry(&rq->rt.pushable_tasks,
1560 struct task_struct, pushable_tasks);
1561
1562 BUG_ON(rq->cpu != task_cpu(p));
1563 BUG_ON(task_current(rq, p));
1564 BUG_ON(p->rt.nr_cpus_allowed <= 1);
1565
1566 BUG_ON(!p->on_rq);
1567 BUG_ON(!rt_task(p));
1568
1569 return p;
1570}
1571
1572/*
1573 * If the current CPU has more than one RT task, see if the non
1574 * running task can migrate over to a CPU that is running a task
1575 * of lesser priority.
1576 */
1577static int push_rt_task(struct rq *rq)
1578{
1579 struct task_struct *next_task;
1580 struct rq *lowest_rq;
1581 int ret = 0;
1582
1583 if (!rq->rt.overloaded)
1584 return 0;
1585
1586 next_task = pick_next_pushable_task(rq);
1587 if (!next_task)
1588 return 0;
1589
1590retry:
1591 if (unlikely(next_task == rq->curr)) {
1592 WARN_ON(1);
1593 return 0;
1594 }
1595
1596 /*
1597 * It's possible that the next_task slipped in of
1598 * higher priority than current. If that's the case
1599 * just reschedule current.
1600 */
1601 if (unlikely(next_task->prio < rq->curr->prio)) {
1602 resched_task(rq->curr);
1603 return 0;
1604 }
1605
1606 /* We might release rq lock */
1607 get_task_struct(next_task);
1608
1609 /* find_lock_lowest_rq locks the rq if found */
1610 lowest_rq = find_lock_lowest_rq(next_task, rq);
1611 if (!lowest_rq) {
1612 struct task_struct *task;
1613 /*
1614 * find_lock_lowest_rq releases rq->lock
1615 * so it is possible that next_task has migrated.
1616 *
1617 * We need to make sure that the task is still on the same
1618 * run-queue and is also still the next task eligible for
1619 * pushing.
1620 */
1621 task = pick_next_pushable_task(rq);
1622 if (task_cpu(next_task) == rq->cpu && task == next_task) {
1623 /*
1624 * The task hasn't migrated, and is still the next
1625 * eligible task, but we failed to find a run-queue
1626 * to push it to. Do not retry in this case, since
1627 * other cpus will pull from us when ready.
1628 */
1629 goto out;
1630 }
1631
1632 if (!task)
1633 /* No more tasks, just exit */
1634 goto out;
1635
1636 /*
1637 * Something has shifted, try again.
1638 */
1639 put_task_struct(next_task);
1640 next_task = task;
1641 goto retry;
1642 }
1643
1644 deactivate_task(rq, next_task, 0);
1645 set_task_cpu(next_task, lowest_rq->cpu);
1646 activate_task(lowest_rq, next_task, 0);
1647 ret = 1;
1648
1649 resched_task(lowest_rq->curr);
1650
1651 double_unlock_balance(rq, lowest_rq);
1652
1653out:
1654 put_task_struct(next_task);
1655
1656 return ret;
1657}
1658
1659static void push_rt_tasks(struct rq *rq)
1660{
1661 /* push_rt_task will return true if it moved an RT */
1662 while (push_rt_task(rq))
1663 ;
1664}
1665
1666static int pull_rt_task(struct rq *this_rq)
1667{
1668 int this_cpu = this_rq->cpu, ret = 0, cpu;
1669 struct task_struct *p;
1670 struct rq *src_rq;
1671
1672 if (likely(!rt_overloaded(this_rq)))
1673 return 0;
1674
1675 for_each_cpu(cpu, this_rq->rd->rto_mask) {
1676 if (this_cpu == cpu)
1677 continue;
1678
1679 src_rq = cpu_rq(cpu);
1680
1681 /*
1682 * Don't bother taking the src_rq->lock if the next highest
1683 * task is known to be lower-priority than our current task.
1684 * This may look racy, but if this value is about to go
1685 * logically higher, the src_rq will push this task away.
1686 * And if its going logically lower, we do not care
1687 */
1688 if (src_rq->rt.highest_prio.next >=
1689 this_rq->rt.highest_prio.curr)
1690 continue;
1691
1692 /*
1693 * We can potentially drop this_rq's lock in
1694 * double_lock_balance, and another CPU could
1695 * alter this_rq
1696 */
1697 double_lock_balance(this_rq, src_rq);
1698
1699 /*
1700 * Are there still pullable RT tasks?
1701 */
1702 if (src_rq->rt.rt_nr_running <= 1)
1703 goto skip;
1704
1705 p = pick_next_highest_task_rt(src_rq, this_cpu);
1706
1707 /*
1708 * Do we have an RT task that preempts
1709 * the to-be-scheduled task?
1710 */
1711 if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
1712 WARN_ON(p == src_rq->curr);
1713 WARN_ON(!p->on_rq);
1714
1715 /*
1716 * There's a chance that p is higher in priority
1717 * than what's currently running on its cpu.
1718 * This is just that p is wakeing up and hasn't
1719 * had a chance to schedule. We only pull
1720 * p if it is lower in priority than the
1721 * current task on the run queue
1722 */
1723 if (p->prio < src_rq->curr->prio)
1724 goto skip;
1725
1726 ret = 1;
1727
1728 deactivate_task(src_rq, p, 0);
1729 set_task_cpu(p, this_cpu);
1730 activate_task(this_rq, p, 0);
1731 /*
1732 * We continue with the search, just in
1733 * case there's an even higher prio task
1734 * in another runqueue. (low likelihood
1735 * but possible)
1736 */
1737 }
1738skip:
1739 double_unlock_balance(this_rq, src_rq);
1740 }
1741
1742 return ret;
1743}
1744
1745static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
1746{
1747 /* Try to pull RT tasks here if we lower this rq's prio */
1748 if (rq->rt.highest_prio.curr > prev->prio)
1749 pull_rt_task(rq);
1750}
1751
1752static void post_schedule_rt(struct rq *rq)
1753{
1754 push_rt_tasks(rq);
1755}
1756
1757/*
1758 * If we are not running and we are not going to reschedule soon, we should
1759 * try to push tasks away now
1760 */
1761static void task_woken_rt(struct rq *rq, struct task_struct *p)
1762{
1763 if (!task_running(rq, p) &&
1764 !test_tsk_need_resched(rq->curr) &&
1765 has_pushable_tasks(rq) &&
1766 p->rt.nr_cpus_allowed > 1 &&
1767 rt_task(rq->curr) &&
1768 (rq->curr->rt.nr_cpus_allowed < 2 ||
1769 rq->curr->prio <= p->prio))
1770 push_rt_tasks(rq);
1771}
1772
1773static void set_cpus_allowed_rt(struct task_struct *p,
1774 const struct cpumask *new_mask)
1775{
1776 int weight = cpumask_weight(new_mask);
1777
1778 BUG_ON(!rt_task(p));
1779
1780 /*
1781 * Update the migration status of the RQ if we have an RT task
1782 * which is running AND changing its weight value.
1783 */
1784 if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) {
1785 struct rq *rq = task_rq(p);
1786
1787 if (!task_current(rq, p)) {
1788 /*
1789 * Make sure we dequeue this task from the pushable list
1790 * before going further. It will either remain off of
1791 * the list because we are no longer pushable, or it
1792 * will be requeued.
1793 */
1794 if (p->rt.nr_cpus_allowed > 1)
1795 dequeue_pushable_task(rq, p);
1796
1797 /*
1798 * Requeue if our weight is changing and still > 1
1799 */
1800 if (weight > 1)
1801 enqueue_pushable_task(rq, p);
1802
1803 }
1804
1805 if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
1806 rq->rt.rt_nr_migratory++;
1807 } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
1808 BUG_ON(!rq->rt.rt_nr_migratory);
1809 rq->rt.rt_nr_migratory--;
1810 }
1811
1812 update_rt_migration(&rq->rt);
1813 }
1814}
1815
1816/* Assumes rq->lock is held */
1817static void rq_online_rt(struct rq *rq)
1818{
1819 if (rq->rt.overloaded)
1820 rt_set_overload(rq);
1821
1822 __enable_runtime(rq);
1823
1824 cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
1825}
1826
1827/* Assumes rq->lock is held */
1828static void rq_offline_rt(struct rq *rq)
1829{
1830 if (rq->rt.overloaded)
1831 rt_clear_overload(rq);
1832
1833 __disable_runtime(rq);
1834
1835 cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
1836}
1837
1838/*
1839 * When switch from the rt queue, we bring ourselves to a position
1840 * that we might want to pull RT tasks from other runqueues.
1841 */
1842static void switched_from_rt(struct rq *rq, struct task_struct *p)
1843{
1844 /*
1845 * If there are other RT tasks then we will reschedule
1846 * and the scheduling of the other RT tasks will handle
1847 * the balancing. But if we are the last RT task
1848 * we may need to handle the pulling of RT tasks
1849 * now.
1850 */
1851 if (p->on_rq && !rq->rt.rt_nr_running)
1852 pull_rt_task(rq);
1853}
1854
1855void init_sched_rt_class(void)
1856{
1857 unsigned int i;
1858
1859 for_each_possible_cpu(i) {
1860 zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
1861 GFP_KERNEL, cpu_to_node(i));
1862 }
1863}
1864#endif /* CONFIG_SMP */
1865
1866/*
1867 * When switching a task to RT, we may overload the runqueue
1868 * with RT tasks. In this case we try to push them off to
1869 * other runqueues.
1870 */
1871static void switched_to_rt(struct rq *rq, struct task_struct *p)
1872{
1873 int check_resched = 1;
1874
1875 /*
1876 * If we are already running, then there's nothing
1877 * that needs to be done. But if we are not running
1878 * we may need to preempt the current running task.
1879 * If that current running task is also an RT task
1880 * then see if we can move to another run queue.
1881 */
1882 if (p->on_rq && rq->curr != p) {
1883#ifdef CONFIG_SMP
1884 if (rq->rt.overloaded && push_rt_task(rq) &&
1885 /* Don't resched if we changed runqueues */
1886 rq != task_rq(p))
1887 check_resched = 0;
1888#endif /* CONFIG_SMP */
1889 if (check_resched && p->prio < rq->curr->prio)
1890 resched_task(rq->curr);
1891 }
1892}
1893
1894/*
1895 * Priority of the task has changed. This may cause
1896 * us to initiate a push or pull.
1897 */
1898static void
1899prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
1900{
1901 if (!p->on_rq)
1902 return;
1903
1904 if (rq->curr == p) {
1905#ifdef CONFIG_SMP
1906 /*
1907 * If our priority decreases while running, we
1908 * may need to pull tasks to this runqueue.
1909 */
1910 if (oldprio < p->prio)
1911 pull_rt_task(rq);
1912 /*
1913 * If there's a higher priority task waiting to run
1914 * then reschedule. Note, the above pull_rt_task
1915 * can release the rq lock and p could migrate.
1916 * Only reschedule if p is still on the same runqueue.
1917 */
1918 if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
1919 resched_task(p);
1920#else
1921 /* For UP simply resched on drop of prio */
1922 if (oldprio < p->prio)
1923 resched_task(p);
1924#endif /* CONFIG_SMP */
1925 } else {
1926 /*
1927 * This task is not running, but if it is
1928 * greater than the current running task
1929 * then reschedule.
1930 */
1931 if (p->prio < rq->curr->prio)
1932 resched_task(rq->curr);
1933 }
1934}
1935
1936static void watchdog(struct rq *rq, struct task_struct *p)
1937{
1938 unsigned long soft, hard;
1939
1940 /* max may change after cur was read, this will be fixed next tick */
1941 soft = task_rlimit(p, RLIMIT_RTTIME);
1942 hard = task_rlimit_max(p, RLIMIT_RTTIME);
1943
1944 if (soft != RLIM_INFINITY) {
1945 unsigned long next;
1946
1947 p->rt.timeout++;
1948 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
1949 if (p->rt.timeout > next)
1950 p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
1951 }
1952}
1953
1954static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
1955{
1956 update_curr_rt(rq);
1957
1958 watchdog(rq, p);
1959
1960 /*
1961 * RR tasks need a special form of timeslice management.
1962 * FIFO tasks have no timeslices.
1963 */
1964 if (p->policy != SCHED_RR)
1965 return;
1966
1967 if (--p->rt.time_slice)
1968 return;
1969
1970 p->rt.time_slice = DEF_TIMESLICE;
1971
1972 /*
1973 * Requeue to the end of queue if we are not the only element
1974 * on the queue:
1975 */
1976 if (p->rt.run_list.prev != p->rt.run_list.next) {
1977 requeue_task_rt(rq, p, 0);
1978 set_tsk_need_resched(p);
1979 }
1980}
1981
1982static void set_curr_task_rt(struct rq *rq)
1983{
1984 struct task_struct *p = rq->curr;
1985
1986 p->se.exec_start = rq->clock_task;
1987
1988 /* The running task is never eligible for pushing */
1989 dequeue_pushable_task(rq, p);
1990}
1991
1992static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
1993{
1994 /*
1995 * Time slice is 0 for SCHED_FIFO tasks
1996 */
1997 if (task->policy == SCHED_RR)
1998 return DEF_TIMESLICE;
1999 else
2000 return 0;
2001}
2002
2003const struct sched_class rt_sched_class = {
2004 .next = &fair_sched_class,
2005 .enqueue_task = enqueue_task_rt,
2006 .dequeue_task = dequeue_task_rt,
2007 .yield_task = yield_task_rt,
2008
2009 .check_preempt_curr = check_preempt_curr_rt,
2010
2011 .pick_next_task = pick_next_task_rt,
2012 .put_prev_task = put_prev_task_rt,
2013
2014#ifdef CONFIG_SMP
2015 .select_task_rq = select_task_rq_rt,
2016
2017 .set_cpus_allowed = set_cpus_allowed_rt,
2018 .rq_online = rq_online_rt,
2019 .rq_offline = rq_offline_rt,
2020 .pre_schedule = pre_schedule_rt,
2021 .post_schedule = post_schedule_rt,
2022 .task_woken = task_woken_rt,
2023 .switched_from = switched_from_rt,
2024#endif
2025
2026 .set_curr_task = set_curr_task_rt,
2027 .task_tick = task_tick_rt,
2028
2029 .get_rr_interval = get_rr_interval_rt,
2030
2031 .prio_changed = prio_changed_rt,
2032 .switched_to = switched_to_rt,
2033};
2034
2035#ifdef CONFIG_SCHED_DEBUG
2036extern void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq);
2037
2038void print_rt_stats(struct seq_file *m, int cpu)
2039{
2040 rt_rq_iter_t iter;
2041 struct rt_rq *rt_rq;
2042
2043 rcu_read_lock();
2044 for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
2045 print_rt_rq(m, cpu, rt_rq);
2046 rcu_read_unlock();
2047}
2048#endif /* CONFIG_SCHED_DEBUG */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
new file mode 100644
index 000000000000..d8d3613a4055
--- /dev/null
+++ b/kernel/sched/sched.h
@@ -0,0 +1,1136 @@
1
2#include <linux/sched.h>
3#include <linux/mutex.h>
4#include <linux/spinlock.h>
5#include <linux/stop_machine.h>
6
7#include "cpupri.h"
8
9extern __read_mostly int scheduler_running;
10
11/*
12 * Convert user-nice values [ -20 ... 0 ... 19 ]
13 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
14 * and back.
15 */
16#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
17#define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
18#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
19
20/*
21 * 'User priority' is the nice value converted to something we
22 * can work with better when scaling various scheduler parameters,
23 * it's a [ 0 ... 39 ] range.
24 */
25#define USER_PRIO(p) ((p)-MAX_RT_PRIO)
26#define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
27#define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
28
29/*
30 * Helpers for converting nanosecond timing to jiffy resolution
31 */
32#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
33
34#define NICE_0_LOAD SCHED_LOAD_SCALE
35#define NICE_0_SHIFT SCHED_LOAD_SHIFT
36
37/*
38 * These are the 'tuning knobs' of the scheduler:
39 *
40 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
41 * Timeslices get refilled after they expire.
42 */
43#define DEF_TIMESLICE (100 * HZ / 1000)
44
45/*
46 * single value that denotes runtime == period, ie unlimited time.
47 */
48#define RUNTIME_INF ((u64)~0ULL)
49
50static inline int rt_policy(int policy)
51{
52 if (policy == SCHED_FIFO || policy == SCHED_RR)
53 return 1;
54 return 0;
55}
56
57static inline int task_has_rt_policy(struct task_struct *p)
58{
59 return rt_policy(p->policy);
60}
61
62/*
63 * This is the priority-queue data structure of the RT scheduling class:
64 */
65struct rt_prio_array {
66 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
67 struct list_head queue[MAX_RT_PRIO];
68};
69
70struct rt_bandwidth {
71 /* nests inside the rq lock: */
72 raw_spinlock_t rt_runtime_lock;
73 ktime_t rt_period;
74 u64 rt_runtime;
75 struct hrtimer rt_period_timer;
76};
77
78extern struct mutex sched_domains_mutex;
79
80#ifdef CONFIG_CGROUP_SCHED
81
82#include <linux/cgroup.h>
83
84struct cfs_rq;
85struct rt_rq;
86
87static LIST_HEAD(task_groups);
88
89struct cfs_bandwidth {
90#ifdef CONFIG_CFS_BANDWIDTH
91 raw_spinlock_t lock;
92 ktime_t period;
93 u64 quota, runtime;
94 s64 hierarchal_quota;
95 u64 runtime_expires;
96
97 int idle, timer_active;
98 struct hrtimer period_timer, slack_timer;
99 struct list_head throttled_cfs_rq;
100
101 /* statistics */
102 int nr_periods, nr_throttled;
103 u64 throttled_time;
104#endif
105};
106
107/* task group related information */
108struct task_group {
109 struct cgroup_subsys_state css;
110
111#ifdef CONFIG_FAIR_GROUP_SCHED
112 /* schedulable entities of this group on each cpu */
113 struct sched_entity **se;
114 /* runqueue "owned" by this group on each cpu */
115 struct cfs_rq **cfs_rq;
116 unsigned long shares;
117
118 atomic_t load_weight;
119#endif
120
121#ifdef CONFIG_RT_GROUP_SCHED
122 struct sched_rt_entity **rt_se;
123 struct rt_rq **rt_rq;
124
125 struct rt_bandwidth rt_bandwidth;
126#endif
127
128 struct rcu_head rcu;
129 struct list_head list;
130
131 struct task_group *parent;
132 struct list_head siblings;
133 struct list_head children;
134
135#ifdef CONFIG_SCHED_AUTOGROUP
136 struct autogroup *autogroup;
137#endif
138
139 struct cfs_bandwidth cfs_bandwidth;
140};
141
142#ifdef CONFIG_FAIR_GROUP_SCHED
143#define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
144
145/*
146 * A weight of 0 or 1 can cause arithmetics problems.
147 * A weight of a cfs_rq is the sum of weights of which entities
148 * are queued on this cfs_rq, so a weight of a entity should not be
149 * too large, so as the shares value of a task group.
150 * (The default weight is 1024 - so there's no practical
151 * limitation from this.)
152 */
153#define MIN_SHARES (1UL << 1)
154#define MAX_SHARES (1UL << 18)
155#endif
156
157/* Default task group.
158 * Every task in system belong to this group at bootup.
159 */
160extern struct task_group root_task_group;
161
162typedef int (*tg_visitor)(struct task_group *, void *);
163
164extern int walk_tg_tree_from(struct task_group *from,
165 tg_visitor down, tg_visitor up, void *data);
166
167/*
168 * Iterate the full tree, calling @down when first entering a node and @up when
169 * leaving it for the final time.
170 *
171 * Caller must hold rcu_lock or sufficient equivalent.
172 */
173static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
174{
175 return walk_tg_tree_from(&root_task_group, down, up, data);
176}
177
178extern int tg_nop(struct task_group *tg, void *data);
179
180extern void free_fair_sched_group(struct task_group *tg);
181extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
182extern void unregister_fair_sched_group(struct task_group *tg, int cpu);
183extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
184 struct sched_entity *se, int cpu,
185 struct sched_entity *parent);
186extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
187extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);
188
189extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
190extern void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
191extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
192
193extern void free_rt_sched_group(struct task_group *tg);
194extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
195extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
196 struct sched_rt_entity *rt_se, int cpu,
197 struct sched_rt_entity *parent);
198
199#else /* CONFIG_CGROUP_SCHED */
200
201struct cfs_bandwidth { };
202
203#endif /* CONFIG_CGROUP_SCHED */
204
205/* CFS-related fields in a runqueue */
206struct cfs_rq {
207 struct load_weight load;
208 unsigned long nr_running, h_nr_running;
209
210 u64 exec_clock;
211 u64 min_vruntime;
212#ifndef CONFIG_64BIT
213 u64 min_vruntime_copy;
214#endif
215
216 struct rb_root tasks_timeline;
217 struct rb_node *rb_leftmost;
218
219 struct list_head tasks;
220 struct list_head *balance_iterator;
221
222 /*
223 * 'curr' points to currently running entity on this cfs_rq.
224 * It is set to NULL otherwise (i.e when none are currently running).
225 */
226 struct sched_entity *curr, *next, *last, *skip;
227
228#ifdef CONFIG_SCHED_DEBUG
229 unsigned int nr_spread_over;
230#endif
231
232#ifdef CONFIG_FAIR_GROUP_SCHED
233 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
234
235 /*
236 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
237 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
238 * (like users, containers etc.)
239 *
240 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
241 * list is used during load balance.
242 */
243 int on_list;
244 struct list_head leaf_cfs_rq_list;
245 struct task_group *tg; /* group that "owns" this runqueue */
246
247#ifdef CONFIG_SMP
248 /*
249 * the part of load.weight contributed by tasks
250 */
251 unsigned long task_weight;
252
253 /*
254 * h_load = weight * f(tg)
255 *
256 * Where f(tg) is the recursive weight fraction assigned to
257 * this group.
258 */
259 unsigned long h_load;
260
261 /*
262 * Maintaining per-cpu shares distribution for group scheduling
263 *
264 * load_stamp is the last time we updated the load average
265 * load_last is the last time we updated the load average and saw load
266 * load_unacc_exec_time is currently unaccounted execution time
267 */
268 u64 load_avg;
269 u64 load_period;
270 u64 load_stamp, load_last, load_unacc_exec_time;
271
272 unsigned long load_contribution;
273#endif /* CONFIG_SMP */
274#ifdef CONFIG_CFS_BANDWIDTH
275 int runtime_enabled;
276 u64 runtime_expires;
277 s64 runtime_remaining;
278
279 u64 throttled_timestamp;
280 int throttled, throttle_count;
281 struct list_head throttled_list;
282#endif /* CONFIG_CFS_BANDWIDTH */
283#endif /* CONFIG_FAIR_GROUP_SCHED */
284};
285
286static inline int rt_bandwidth_enabled(void)
287{
288 return sysctl_sched_rt_runtime >= 0;
289}
290
291/* Real-Time classes' related field in a runqueue: */
292struct rt_rq {
293 struct rt_prio_array active;
294 unsigned long rt_nr_running;
295#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
296 struct {
297 int curr; /* highest queued rt task prio */
298#ifdef CONFIG_SMP
299 int next; /* next highest */
300#endif
301 } highest_prio;
302#endif
303#ifdef CONFIG_SMP
304 unsigned long rt_nr_migratory;
305 unsigned long rt_nr_total;
306 int overloaded;
307 struct plist_head pushable_tasks;
308#endif
309 int rt_throttled;
310 u64 rt_time;
311 u64 rt_runtime;
312 /* Nests inside the rq lock: */
313 raw_spinlock_t rt_runtime_lock;
314
315#ifdef CONFIG_RT_GROUP_SCHED
316 unsigned long rt_nr_boosted;
317
318 struct rq *rq;
319 struct list_head leaf_rt_rq_list;
320 struct task_group *tg;
321#endif
322};
323
324#ifdef CONFIG_SMP
325
326/*
327 * We add the notion of a root-domain which will be used to define per-domain
328 * variables. Each exclusive cpuset essentially defines an island domain by
329 * fully partitioning the member cpus from any other cpuset. Whenever a new
330 * exclusive cpuset is created, we also create and attach a new root-domain
331 * object.
332 *
333 */
334struct root_domain {
335 atomic_t refcount;
336 atomic_t rto_count;
337 struct rcu_head rcu;
338 cpumask_var_t span;
339 cpumask_var_t online;
340
341 /*
342 * The "RT overload" flag: it gets set if a CPU has more than
343 * one runnable RT task.
344 */
345 cpumask_var_t rto_mask;
346 struct cpupri cpupri;
347};
348
349extern struct root_domain def_root_domain;
350
351#endif /* CONFIG_SMP */
352
353/*
354 * This is the main, per-CPU runqueue data structure.
355 *
356 * Locking rule: those places that want to lock multiple runqueues
357 * (such as the load balancing or the thread migration code), lock
358 * acquire operations must be ordered by ascending &runqueue.
359 */
360struct rq {
361 /* runqueue lock: */
362 raw_spinlock_t lock;
363
364 /*
365 * nr_running and cpu_load should be in the same cacheline because
366 * remote CPUs use both these fields when doing load calculation.
367 */
368 unsigned long nr_running;
369 #define CPU_LOAD_IDX_MAX 5
370 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
371 unsigned long last_load_update_tick;
372#ifdef CONFIG_NO_HZ
373 u64 nohz_stamp;
374 unsigned long nohz_flags;
375#endif
376 int skip_clock_update;
377
378 /* capture load from *all* tasks on this cpu: */
379 struct load_weight load;
380 unsigned long nr_load_updates;
381 u64 nr_switches;
382
383 struct cfs_rq cfs;
384 struct rt_rq rt;
385
386#ifdef CONFIG_FAIR_GROUP_SCHED
387 /* list of leaf cfs_rq on this cpu: */
388 struct list_head leaf_cfs_rq_list;
389#endif
390#ifdef CONFIG_RT_GROUP_SCHED
391 struct list_head leaf_rt_rq_list;
392#endif
393
394 /*
395 * This is part of a global counter where only the total sum
396 * over all CPUs matters. A task can increase this counter on
397 * one CPU and if it got migrated afterwards it may decrease
398 * it on another CPU. Always updated under the runqueue lock:
399 */
400 unsigned long nr_uninterruptible;
401
402 struct task_struct *curr, *idle, *stop;
403 unsigned long next_balance;
404 struct mm_struct *prev_mm;
405
406 u64 clock;
407 u64 clock_task;
408
409 atomic_t nr_iowait;
410
411#ifdef CONFIG_SMP
412 struct root_domain *rd;
413 struct sched_domain *sd;
414
415 unsigned long cpu_power;
416
417 unsigned char idle_balance;
418 /* For active balancing */
419 int post_schedule;
420 int active_balance;
421 int push_cpu;
422 struct cpu_stop_work active_balance_work;
423 /* cpu of this runqueue: */
424 int cpu;
425 int online;
426
427 u64 rt_avg;
428 u64 age_stamp;
429 u64 idle_stamp;
430 u64 avg_idle;
431#endif
432
433#ifdef CONFIG_IRQ_TIME_ACCOUNTING
434 u64 prev_irq_time;
435#endif
436#ifdef CONFIG_PARAVIRT
437 u64 prev_steal_time;
438#endif
439#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
440 u64 prev_steal_time_rq;
441#endif
442
443 /* calc_load related fields */
444 unsigned long calc_load_update;
445 long calc_load_active;
446
447#ifdef CONFIG_SCHED_HRTICK
448#ifdef CONFIG_SMP
449 int hrtick_csd_pending;
450 struct call_single_data hrtick_csd;
451#endif
452 struct hrtimer hrtick_timer;
453#endif
454
455#ifdef CONFIG_SCHEDSTATS
456 /* latency stats */
457 struct sched_info rq_sched_info;
458 unsigned long long rq_cpu_time;
459 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
460
461 /* sys_sched_yield() stats */
462 unsigned int yld_count;
463
464 /* schedule() stats */
465 unsigned int sched_switch;
466 unsigned int sched_count;
467 unsigned int sched_goidle;
468
469 /* try_to_wake_up() stats */
470 unsigned int ttwu_count;
471 unsigned int ttwu_local;
472#endif
473
474#ifdef CONFIG_SMP
475 struct llist_head wake_list;
476#endif
477};
478
479static inline int cpu_of(struct rq *rq)
480{
481#ifdef CONFIG_SMP
482 return rq->cpu;
483#else
484 return 0;
485#endif
486}
487
488DECLARE_PER_CPU(struct rq, runqueues);
489
490#define rcu_dereference_check_sched_domain(p) \
491 rcu_dereference_check((p), \
492 lockdep_is_held(&sched_domains_mutex))
493
494/*
495 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
496 * See detach_destroy_domains: synchronize_sched for details.
497 *
498 * The domain tree of any CPU may only be accessed from within
499 * preempt-disabled sections.
500 */
501#define for_each_domain(cpu, __sd) \
502 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
503
504#define for_each_lower_domain(sd) for (; sd; sd = sd->child)
505
506#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
507#define this_rq() (&__get_cpu_var(runqueues))
508#define task_rq(p) cpu_rq(task_cpu(p))
509#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
510#define raw_rq() (&__raw_get_cpu_var(runqueues))
511
512#include "stats.h"
513#include "auto_group.h"
514
515#ifdef CONFIG_CGROUP_SCHED
516
517/*
518 * Return the group to which this tasks belongs.
519 *
520 * We use task_subsys_state_check() and extend the RCU verification with
521 * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each
522 * task it moves into the cgroup. Therefore by holding either of those locks,
523 * we pin the task to the current cgroup.
524 */
525static inline struct task_group *task_group(struct task_struct *p)
526{
527 struct task_group *tg;
528 struct cgroup_subsys_state *css;
529
530 css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
531 lockdep_is_held(&p->pi_lock) ||
532 lockdep_is_held(&task_rq(p)->lock));
533 tg = container_of(css, struct task_group, css);
534
535 return autogroup_task_group(p, tg);
536}
537
538/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
539static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
540{
541#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
542 struct task_group *tg = task_group(p);
543#endif
544
545#ifdef CONFIG_FAIR_GROUP_SCHED
546 p->se.cfs_rq = tg->cfs_rq[cpu];
547 p->se.parent = tg->se[cpu];
548#endif
549
550#ifdef CONFIG_RT_GROUP_SCHED
551 p->rt.rt_rq = tg->rt_rq[cpu];
552 p->rt.parent = tg->rt_se[cpu];
553#endif
554}
555
556#else /* CONFIG_CGROUP_SCHED */
557
558static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
559static inline struct task_group *task_group(struct task_struct *p)
560{
561 return NULL;
562}
563
564#endif /* CONFIG_CGROUP_SCHED */
565
566static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
567{
568 set_task_rq(p, cpu);
569#ifdef CONFIG_SMP
570 /*
571 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
572 * successfuly executed on another CPU. We must ensure that updates of
573 * per-task data have been completed by this moment.
574 */
575 smp_wmb();
576 task_thread_info(p)->cpu = cpu;
577#endif
578}
579
580/*
581 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
582 */
583#ifdef CONFIG_SCHED_DEBUG
584# include <linux/jump_label.h>
585# define const_debug __read_mostly
586#else
587# define const_debug const
588#endif
589
590extern const_debug unsigned int sysctl_sched_features;
591
592#define SCHED_FEAT(name, enabled) \
593 __SCHED_FEAT_##name ,
594
595enum {
596#include "features.h"
597 __SCHED_FEAT_NR,
598};
599
600#undef SCHED_FEAT
601
602#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
603static __always_inline bool static_branch__true(struct jump_label_key *key)
604{
605 return likely(static_branch(key)); /* Not out of line branch. */
606}
607
608static __always_inline bool static_branch__false(struct jump_label_key *key)
609{
610 return unlikely(static_branch(key)); /* Out of line branch. */
611}
612
613#define SCHED_FEAT(name, enabled) \
614static __always_inline bool static_branch_##name(struct jump_label_key *key) \
615{ \
616 return static_branch__##enabled(key); \
617}
618
619#include "features.h"
620
621#undef SCHED_FEAT
622
623extern struct jump_label_key sched_feat_keys[__SCHED_FEAT_NR];
624#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
625#else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
626#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
627#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
628
629static inline u64 global_rt_period(void)
630{
631 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
632}
633
634static inline u64 global_rt_runtime(void)
635{
636 if (sysctl_sched_rt_runtime < 0)
637 return RUNTIME_INF;
638
639 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
640}
641
642
643
644static inline int task_current(struct rq *rq, struct task_struct *p)
645{
646 return rq->curr == p;
647}
648
649static inline int task_running(struct rq *rq, struct task_struct *p)
650{
651#ifdef CONFIG_SMP
652 return p->on_cpu;
653#else
654 return task_current(rq, p);
655#endif
656}
657
658
659#ifndef prepare_arch_switch
660# define prepare_arch_switch(next) do { } while (0)
661#endif
662#ifndef finish_arch_switch
663# define finish_arch_switch(prev) do { } while (0)
664#endif
665
666#ifndef __ARCH_WANT_UNLOCKED_CTXSW
667static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
668{
669#ifdef CONFIG_SMP
670 /*
671 * We can optimise this out completely for !SMP, because the
672 * SMP rebalancing from interrupt is the only thing that cares
673 * here.
674 */
675 next->on_cpu = 1;
676#endif
677}
678
679static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
680{
681#ifdef CONFIG_SMP
682 /*
683 * After ->on_cpu is cleared, the task can be moved to a different CPU.
684 * We must ensure this doesn't happen until the switch is completely
685 * finished.
686 */
687 smp_wmb();
688 prev->on_cpu = 0;
689#endif
690#ifdef CONFIG_DEBUG_SPINLOCK
691 /* this is a valid case when another task releases the spinlock */
692 rq->lock.owner = current;
693#endif
694 /*
695 * If we are tracking spinlock dependencies then we have to
696 * fix up the runqueue lock - which gets 'carried over' from
697 * prev into current:
698 */
699 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
700
701 raw_spin_unlock_irq(&rq->lock);
702}
703
704#else /* __ARCH_WANT_UNLOCKED_CTXSW */
705static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
706{
707#ifdef CONFIG_SMP
708 /*
709 * We can optimise this out completely for !SMP, because the
710 * SMP rebalancing from interrupt is the only thing that cares
711 * here.
712 */
713 next->on_cpu = 1;
714#endif
715#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
716 raw_spin_unlock_irq(&rq->lock);
717#else
718 raw_spin_unlock(&rq->lock);
719#endif
720}
721
722static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
723{
724#ifdef CONFIG_SMP
725 /*
726 * After ->on_cpu is cleared, the task can be moved to a different CPU.
727 * We must ensure this doesn't happen until the switch is completely
728 * finished.
729 */
730 smp_wmb();
731 prev->on_cpu = 0;
732#endif
733#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
734 local_irq_enable();
735#endif
736}
737#endif /* __ARCH_WANT_UNLOCKED_CTXSW */
738
739
740static inline void update_load_add(struct load_weight *lw, unsigned long inc)
741{
742 lw->weight += inc;
743 lw->inv_weight = 0;
744}
745
746static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
747{
748 lw->weight -= dec;
749 lw->inv_weight = 0;
750}
751
752static inline void update_load_set(struct load_weight *lw, unsigned long w)
753{
754 lw->weight = w;
755 lw->inv_weight = 0;
756}
757
758/*
759 * To aid in avoiding the subversion of "niceness" due to uneven distribution
760 * of tasks with abnormal "nice" values across CPUs the contribution that
761 * each task makes to its run queue's load is weighted according to its
762 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
763 * scaled version of the new time slice allocation that they receive on time
764 * slice expiry etc.
765 */
766
767#define WEIGHT_IDLEPRIO 3
768#define WMULT_IDLEPRIO 1431655765
769
770/*
771 * Nice levels are multiplicative, with a gentle 10% change for every
772 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
773 * nice 1, it will get ~10% less CPU time than another CPU-bound task
774 * that remained on nice 0.
775 *
776 * The "10% effect" is relative and cumulative: from _any_ nice level,
777 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
778 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
779 * If a task goes up by ~10% and another task goes down by ~10% then
780 * the relative distance between them is ~25%.)
781 */
782static const int prio_to_weight[40] = {
783 /* -20 */ 88761, 71755, 56483, 46273, 36291,
784 /* -15 */ 29154, 23254, 18705, 14949, 11916,
785 /* -10 */ 9548, 7620, 6100, 4904, 3906,
786 /* -5 */ 3121, 2501, 1991, 1586, 1277,
787 /* 0 */ 1024, 820, 655, 526, 423,
788 /* 5 */ 335, 272, 215, 172, 137,
789 /* 10 */ 110, 87, 70, 56, 45,
790 /* 15 */ 36, 29, 23, 18, 15,
791};
792
793/*
794 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
795 *
796 * In cases where the weight does not change often, we can use the
797 * precalculated inverse to speed up arithmetics by turning divisions
798 * into multiplications:
799 */
800static const u32 prio_to_wmult[40] = {
801 /* -20 */ 48388, 59856, 76040, 92818, 118348,
802 /* -15 */ 147320, 184698, 229616, 287308, 360437,
803 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
804 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
805 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
806 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
807 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
808 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
809};
810
811/* Time spent by the tasks of the cpu accounting group executing in ... */
812enum cpuacct_stat_index {
813 CPUACCT_STAT_USER, /* ... user mode */
814 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
815
816 CPUACCT_STAT_NSTATS,
817};
818
819
820#define sched_class_highest (&stop_sched_class)
821#define for_each_class(class) \
822 for (class = sched_class_highest; class; class = class->next)
823
824extern const struct sched_class stop_sched_class;
825extern const struct sched_class rt_sched_class;
826extern const struct sched_class fair_sched_class;
827extern const struct sched_class idle_sched_class;
828
829
830#ifdef CONFIG_SMP
831
832extern void trigger_load_balance(struct rq *rq, int cpu);
833extern void idle_balance(int this_cpu, struct rq *this_rq);
834
835#else /* CONFIG_SMP */
836
837static inline void idle_balance(int cpu, struct rq *rq)
838{
839}
840
841#endif
842
843extern void sysrq_sched_debug_show(void);
844extern void sched_init_granularity(void);
845extern void update_max_interval(void);
846extern void update_group_power(struct sched_domain *sd, int cpu);
847extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
848extern void init_sched_rt_class(void);
849extern void init_sched_fair_class(void);
850
851extern void resched_task(struct task_struct *p);
852extern void resched_cpu(int cpu);
853
854extern struct rt_bandwidth def_rt_bandwidth;
855extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
856
857extern void update_cpu_load(struct rq *this_rq);
858
859#ifdef CONFIG_CGROUP_CPUACCT
860#include <linux/cgroup.h>
861/* track cpu usage of a group of tasks and its child groups */
862struct cpuacct {
863 struct cgroup_subsys_state css;
864 /* cpuusage holds pointer to a u64-type object on every cpu */
865 u64 __percpu *cpuusage;
866 struct kernel_cpustat __percpu *cpustat;
867};
868
869/* return cpu accounting group corresponding to this container */
870static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
871{
872 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
873 struct cpuacct, css);
874}
875
876/* return cpu accounting group to which this task belongs */
877static inline struct cpuacct *task_ca(struct task_struct *tsk)
878{
879 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
880 struct cpuacct, css);
881}
882
883static inline struct cpuacct *parent_ca(struct cpuacct *ca)
884{
885 if (!ca || !ca->css.cgroup->parent)
886 return NULL;
887 return cgroup_ca(ca->css.cgroup->parent);
888}
889
890extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
891#else
892static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
893#endif
894
895static inline void inc_nr_running(struct rq *rq)
896{
897 rq->nr_running++;
898}
899
900static inline void dec_nr_running(struct rq *rq)
901{
902 rq->nr_running--;
903}
904
905extern void update_rq_clock(struct rq *rq);
906
907extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
908extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
909
910extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);
911
912extern const_debug unsigned int sysctl_sched_time_avg;
913extern const_debug unsigned int sysctl_sched_nr_migrate;
914extern const_debug unsigned int sysctl_sched_migration_cost;
915
916static inline u64 sched_avg_period(void)
917{
918 return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
919}
920
921void calc_load_account_idle(struct rq *this_rq);
922
923#ifdef CONFIG_SCHED_HRTICK
924
925/*
926 * Use hrtick when:
927 * - enabled by features
928 * - hrtimer is actually high res
929 */
930static inline int hrtick_enabled(struct rq *rq)
931{
932 if (!sched_feat(HRTICK))
933 return 0;
934 if (!cpu_active(cpu_of(rq)))
935 return 0;
936 return hrtimer_is_hres_active(&rq->hrtick_timer);
937}
938
939void hrtick_start(struct rq *rq, u64 delay);
940
941#else
942
943static inline int hrtick_enabled(struct rq *rq)
944{
945 return 0;
946}
947
948#endif /* CONFIG_SCHED_HRTICK */
949
950#ifdef CONFIG_SMP
951extern void sched_avg_update(struct rq *rq);
952static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
953{
954 rq->rt_avg += rt_delta;
955 sched_avg_update(rq);
956}
957#else
958static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
959static inline void sched_avg_update(struct rq *rq) { }
960#endif
961
962extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period);
963
964#ifdef CONFIG_SMP
965#ifdef CONFIG_PREEMPT
966
967static inline void double_rq_lock(struct rq *rq1, struct rq *rq2);
968
969/*
970 * fair double_lock_balance: Safely acquires both rq->locks in a fair
971 * way at the expense of forcing extra atomic operations in all
972 * invocations. This assures that the double_lock is acquired using the
973 * same underlying policy as the spinlock_t on this architecture, which
974 * reduces latency compared to the unfair variant below. However, it
975 * also adds more overhead and therefore may reduce throughput.
976 */
977static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
978 __releases(this_rq->lock)
979 __acquires(busiest->lock)
980 __acquires(this_rq->lock)
981{
982 raw_spin_unlock(&this_rq->lock);
983 double_rq_lock(this_rq, busiest);
984
985 return 1;
986}
987
988#else
989/*
990 * Unfair double_lock_balance: Optimizes throughput at the expense of
991 * latency by eliminating extra atomic operations when the locks are
992 * already in proper order on entry. This favors lower cpu-ids and will
993 * grant the double lock to lower cpus over higher ids under contention,
994 * regardless of entry order into the function.
995 */
996static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
997 __releases(this_rq->lock)
998 __acquires(busiest->lock)
999 __acquires(this_rq->lock)
1000{
1001 int ret = 0;
1002
1003 if (unlikely(!raw_spin_trylock(&busiest->lock))) {
1004 if (busiest < this_rq) {
1005 raw_spin_unlock(&this_rq->lock);
1006 raw_spin_lock(&busiest->lock);
1007 raw_spin_lock_nested(&this_rq->lock,
1008 SINGLE_DEPTH_NESTING);
1009 ret = 1;
1010 } else
1011 raw_spin_lock_nested(&busiest->lock,
1012 SINGLE_DEPTH_NESTING);
1013 }
1014 return ret;
1015}
1016
1017#endif /* CONFIG_PREEMPT */
1018
1019/*
1020 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1021 */
1022static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1023{
1024 if (unlikely(!irqs_disabled())) {
1025 /* printk() doesn't work good under rq->lock */
1026 raw_spin_unlock(&this_rq->lock);
1027 BUG_ON(1);
1028 }
1029
1030 return _double_lock_balance(this_rq, busiest);
1031}
1032
1033static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1034 __releases(busiest->lock)
1035{
1036 raw_spin_unlock(&busiest->lock);
1037 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1038}
1039
1040/*
1041 * double_rq_lock - safely lock two runqueues
1042 *
1043 * Note this does not disable interrupts like task_rq_lock,
1044 * you need to do so manually before calling.
1045 */
1046static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1047 __acquires(rq1->lock)
1048 __acquires(rq2->lock)
1049{
1050 BUG_ON(!irqs_disabled());
1051 if (rq1 == rq2) {
1052 raw_spin_lock(&rq1->lock);
1053 __acquire(rq2->lock); /* Fake it out ;) */
1054 } else {
1055 if (rq1 < rq2) {
1056 raw_spin_lock(&rq1->lock);
1057 raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
1058 } else {
1059 raw_spin_lock(&rq2->lock);
1060 raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
1061 }
1062 }
1063}
1064
1065/*
1066 * double_rq_unlock - safely unlock two runqueues
1067 *
1068 * Note this does not restore interrupts like task_rq_unlock,
1069 * you need to do so manually after calling.
1070 */
1071static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1072 __releases(rq1->lock)
1073 __releases(rq2->lock)
1074{
1075 raw_spin_unlock(&rq1->lock);
1076 if (rq1 != rq2)
1077 raw_spin_unlock(&rq2->lock);
1078 else
1079 __release(rq2->lock);
1080}
1081
1082#else /* CONFIG_SMP */
1083
1084/*
1085 * double_rq_lock - safely lock two runqueues
1086 *
1087 * Note this does not disable interrupts like task_rq_lock,
1088 * you need to do so manually before calling.
1089 */
1090static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
1091 __acquires(rq1->lock)
1092 __acquires(rq2->lock)
1093{
1094 BUG_ON(!irqs_disabled());
1095 BUG_ON(rq1 != rq2);
1096 raw_spin_lock(&rq1->lock);
1097 __acquire(rq2->lock); /* Fake it out ;) */
1098}
1099
1100/*
1101 * double_rq_unlock - safely unlock two runqueues
1102 *
1103 * Note this does not restore interrupts like task_rq_unlock,
1104 * you need to do so manually after calling.
1105 */
1106static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
1107 __releases(rq1->lock)
1108 __releases(rq2->lock)
1109{
1110 BUG_ON(rq1 != rq2);
1111 raw_spin_unlock(&rq1->lock);
1112 __release(rq2->lock);
1113}
1114
1115#endif
1116
1117extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
1118extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);
1119extern void print_cfs_stats(struct seq_file *m, int cpu);
1120extern void print_rt_stats(struct seq_file *m, int cpu);
1121
1122extern void init_cfs_rq(struct cfs_rq *cfs_rq);
1123extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
1124extern void unthrottle_offline_cfs_rqs(struct rq *rq);
1125
1126extern void account_cfs_bandwidth_used(int enabled, int was_enabled);
1127
1128#ifdef CONFIG_NO_HZ
1129enum rq_nohz_flag_bits {
1130 NOHZ_TICK_STOPPED,
1131 NOHZ_BALANCE_KICK,
1132 NOHZ_IDLE,
1133};
1134
1135#define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
1136#endif
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
new file mode 100644
index 000000000000..2a581ba8e190
--- /dev/null
+++ b/kernel/sched/stats.c
@@ -0,0 +1,111 @@
1
2#include <linux/slab.h>
3#include <linux/fs.h>
4#include <linux/seq_file.h>
5#include <linux/proc_fs.h>
6
7#include "sched.h"
8
9/*
10 * bump this up when changing the output format or the meaning of an existing
11 * format, so that tools can adapt (or abort)
12 */
13#define SCHEDSTAT_VERSION 15
14
15static int show_schedstat(struct seq_file *seq, void *v)
16{
17 int cpu;
18 int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
19 char *mask_str = kmalloc(mask_len, GFP_KERNEL);
20
21 if (mask_str == NULL)
22 return -ENOMEM;
23
24 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
25 seq_printf(seq, "timestamp %lu\n", jiffies);
26 for_each_online_cpu(cpu) {
27 struct rq *rq = cpu_rq(cpu);
28#ifdef CONFIG_SMP
29 struct sched_domain *sd;
30 int dcount = 0;
31#endif
32
33 /* runqueue-specific stats */
34 seq_printf(seq,
35 "cpu%d %u %u %u %u %u %u %llu %llu %lu",
36 cpu, rq->yld_count,
37 rq->sched_switch, rq->sched_count, rq->sched_goidle,
38 rq->ttwu_count, rq->ttwu_local,
39 rq->rq_cpu_time,
40 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
41
42 seq_printf(seq, "\n");
43
44#ifdef CONFIG_SMP
45 /* domain-specific stats */
46 rcu_read_lock();
47 for_each_domain(cpu, sd) {
48 enum cpu_idle_type itype;
49
50 cpumask_scnprintf(mask_str, mask_len,
51 sched_domain_span(sd));
52 seq_printf(seq, "domain%d %s", dcount++, mask_str);
53 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
54 itype++) {
55 seq_printf(seq, " %u %u %u %u %u %u %u %u",
56 sd->lb_count[itype],
57 sd->lb_balanced[itype],
58 sd->lb_failed[itype],
59 sd->lb_imbalance[itype],
60 sd->lb_gained[itype],
61 sd->lb_hot_gained[itype],
62 sd->lb_nobusyq[itype],
63 sd->lb_nobusyg[itype]);
64 }
65 seq_printf(seq,
66 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
67 sd->alb_count, sd->alb_failed, sd->alb_pushed,
68 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
69 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
70 sd->ttwu_wake_remote, sd->ttwu_move_affine,
71 sd->ttwu_move_balance);
72 }
73 rcu_read_unlock();
74#endif
75 }
76 kfree(mask_str);
77 return 0;
78}
79
80static int schedstat_open(struct inode *inode, struct file *file)
81{
82 unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
83 char *buf = kmalloc(size, GFP_KERNEL);
84 struct seq_file *m;
85 int res;
86
87 if (!buf)
88 return -ENOMEM;
89 res = single_open(file, show_schedstat, NULL);
90 if (!res) {
91 m = file->private_data;
92 m->buf = buf;
93 m->size = size;
94 } else
95 kfree(buf);
96 return res;
97}
98
99static const struct file_operations proc_schedstat_operations = {
100 .open = schedstat_open,
101 .read = seq_read,
102 .llseek = seq_lseek,
103 .release = single_release,
104};
105
106static int __init proc_schedstat_init(void)
107{
108 proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
109 return 0;
110}
111module_init(proc_schedstat_init);
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
new file mode 100644
index 000000000000..2ef90a51ec5e
--- /dev/null
+++ b/kernel/sched/stats.h
@@ -0,0 +1,231 @@
1
2#ifdef CONFIG_SCHEDSTATS
3
4/*
5 * Expects runqueue lock to be held for atomicity of update
6 */
7static inline void
8rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
9{
10 if (rq) {
11 rq->rq_sched_info.run_delay += delta;
12 rq->rq_sched_info.pcount++;
13 }
14}
15
16/*
17 * Expects runqueue lock to be held for atomicity of update
18 */
19static inline void
20rq_sched_info_depart(struct rq *rq, unsigned long long delta)
21{
22 if (rq)
23 rq->rq_cpu_time += delta;
24}
25
26static inline void
27rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
28{
29 if (rq)
30 rq->rq_sched_info.run_delay += delta;
31}
32# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
33# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
34# define schedstat_set(var, val) do { var = (val); } while (0)
35#else /* !CONFIG_SCHEDSTATS */
36static inline void
37rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
38{}
39static inline void
40rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
41{}
42static inline void
43rq_sched_info_depart(struct rq *rq, unsigned long long delta)
44{}
45# define schedstat_inc(rq, field) do { } while (0)
46# define schedstat_add(rq, field, amt) do { } while (0)
47# define schedstat_set(var, val) do { } while (0)
48#endif
49
50#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
51static inline void sched_info_reset_dequeued(struct task_struct *t)
52{
53 t->sched_info.last_queued = 0;
54}
55
56/*
57 * We are interested in knowing how long it was from the *first* time a
58 * task was queued to the time that it finally hit a cpu, we call this routine
59 * from dequeue_task() to account for possible rq->clock skew across cpus. The
60 * delta taken on each cpu would annul the skew.
61 */
62static inline void sched_info_dequeued(struct task_struct *t)
63{
64 unsigned long long now = task_rq(t)->clock, delta = 0;
65
66 if (unlikely(sched_info_on()))
67 if (t->sched_info.last_queued)
68 delta = now - t->sched_info.last_queued;
69 sched_info_reset_dequeued(t);
70 t->sched_info.run_delay += delta;
71
72 rq_sched_info_dequeued(task_rq(t), delta);
73}
74
75/*
76 * Called when a task finally hits the cpu. We can now calculate how
77 * long it was waiting to run. We also note when it began so that we
78 * can keep stats on how long its timeslice is.
79 */
80static void sched_info_arrive(struct task_struct *t)
81{
82 unsigned long long now = task_rq(t)->clock, delta = 0;
83
84 if (t->sched_info.last_queued)
85 delta = now - t->sched_info.last_queued;
86 sched_info_reset_dequeued(t);
87 t->sched_info.run_delay += delta;
88 t->sched_info.last_arrival = now;
89 t->sched_info.pcount++;
90
91 rq_sched_info_arrive(task_rq(t), delta);
92}
93
94/*
95 * This function is only called from enqueue_task(), but also only updates
96 * the timestamp if it is already not set. It's assumed that
97 * sched_info_dequeued() will clear that stamp when appropriate.
98 */
99static inline void sched_info_queued(struct task_struct *t)
100{
101 if (unlikely(sched_info_on()))
102 if (!t->sched_info.last_queued)
103 t->sched_info.last_queued = task_rq(t)->clock;
104}
105
106/*
107 * Called when a process ceases being the active-running process, either
108 * voluntarily or involuntarily. Now we can calculate how long we ran.
109 * Also, if the process is still in the TASK_RUNNING state, call
110 * sched_info_queued() to mark that it has now again started waiting on
111 * the runqueue.
112 */
113static inline void sched_info_depart(struct task_struct *t)
114{
115 unsigned long long delta = task_rq(t)->clock -
116 t->sched_info.last_arrival;
117
118 rq_sched_info_depart(task_rq(t), delta);
119
120 if (t->state == TASK_RUNNING)
121 sched_info_queued(t);
122}
123
124/*
125 * Called when tasks are switched involuntarily due, typically, to expiring
126 * their time slice. (This may also be called when switching to or from
127 * the idle task.) We are only called when prev != next.
128 */
129static inline void
130__sched_info_switch(struct task_struct *prev, struct task_struct *next)
131{
132 struct rq *rq = task_rq(prev);
133
134 /*
135 * prev now departs the cpu. It's not interesting to record
136 * stats about how efficient we were at scheduling the idle
137 * process, however.
138 */
139 if (prev != rq->idle)
140 sched_info_depart(prev);
141
142 if (next != rq->idle)
143 sched_info_arrive(next);
144}
145static inline void
146sched_info_switch(struct task_struct *prev, struct task_struct *next)
147{
148 if (unlikely(sched_info_on()))
149 __sched_info_switch(prev, next);
150}
151#else
152#define sched_info_queued(t) do { } while (0)
153#define sched_info_reset_dequeued(t) do { } while (0)
154#define sched_info_dequeued(t) do { } while (0)
155#define sched_info_switch(t, next) do { } while (0)
156#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
157
158/*
159 * The following are functions that support scheduler-internal time accounting.
160 * These functions are generally called at the timer tick. None of this depends
161 * on CONFIG_SCHEDSTATS.
162 */
163
164/**
165 * account_group_user_time - Maintain utime for a thread group.
166 *
167 * @tsk: Pointer to task structure.
168 * @cputime: Time value by which to increment the utime field of the
169 * thread_group_cputime structure.
170 *
171 * If thread group time is being maintained, get the structure for the
172 * running CPU and update the utime field there.
173 */
174static inline void account_group_user_time(struct task_struct *tsk,
175 cputime_t cputime)
176{
177 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
178
179 if (!cputimer->running)
180 return;
181
182 raw_spin_lock(&cputimer->lock);
183 cputimer->cputime.utime += cputime;
184 raw_spin_unlock(&cputimer->lock);
185}
186
187/**
188 * account_group_system_time - Maintain stime for a thread group.
189 *
190 * @tsk: Pointer to task structure.
191 * @cputime: Time value by which to increment the stime field of the
192 * thread_group_cputime structure.
193 *
194 * If thread group time is being maintained, get the structure for the
195 * running CPU and update the stime field there.
196 */
197static inline void account_group_system_time(struct task_struct *tsk,
198 cputime_t cputime)
199{
200 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
201
202 if (!cputimer->running)
203 return;
204
205 raw_spin_lock(&cputimer->lock);
206 cputimer->cputime.stime += cputime;
207 raw_spin_unlock(&cputimer->lock);
208}
209
210/**
211 * account_group_exec_runtime - Maintain exec runtime for a thread group.
212 *
213 * @tsk: Pointer to task structure.
214 * @ns: Time value by which to increment the sum_exec_runtime field
215 * of the thread_group_cputime structure.
216 *
217 * If thread group time is being maintained, get the structure for the
218 * running CPU and update the sum_exec_runtime field there.
219 */
220static inline void account_group_exec_runtime(struct task_struct *tsk,
221 unsigned long long ns)
222{
223 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
224
225 if (!cputimer->running)
226 return;
227
228 raw_spin_lock(&cputimer->lock);
229 cputimer->cputime.sum_exec_runtime += ns;
230 raw_spin_unlock(&cputimer->lock);
231}
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
new file mode 100644
index 000000000000..7b386e86fd23
--- /dev/null
+++ b/kernel/sched/stop_task.c
@@ -0,0 +1,108 @@
1#include "sched.h"
2
3/*
4 * stop-task scheduling class.
5 *
6 * The stop task is the highest priority task in the system, it preempts
7 * everything and will be preempted by nothing.
8 *
9 * See kernel/stop_machine.c
10 */
11
12#ifdef CONFIG_SMP
13static int
14select_task_rq_stop(struct task_struct *p, int sd_flag, int flags)
15{
16 return task_cpu(p); /* stop tasks as never migrate */
17}
18#endif /* CONFIG_SMP */
19
20static void
21check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
22{
23 /* we're never preempted */
24}
25
26static struct task_struct *pick_next_task_stop(struct rq *rq)
27{
28 struct task_struct *stop = rq->stop;
29
30 if (stop && stop->on_rq)
31 return stop;
32
33 return NULL;
34}
35
36static void
37enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
38{
39 inc_nr_running(rq);
40}
41
42static void
43dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
44{
45 dec_nr_running(rq);
46}
47
48static void yield_task_stop(struct rq *rq)
49{
50 BUG(); /* the stop task should never yield, its pointless. */
51}
52
53static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
54{
55}
56
57static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
58{
59}
60
61static void set_curr_task_stop(struct rq *rq)
62{
63}
64
65static void switched_to_stop(struct rq *rq, struct task_struct *p)
66{
67 BUG(); /* its impossible to change to this class */
68}
69
70static void
71prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
72{
73 BUG(); /* how!?, what priority? */
74}
75
76static unsigned int
77get_rr_interval_stop(struct rq *rq, struct task_struct *task)
78{
79 return 0;
80}
81
82/*
83 * Simple, special scheduling class for the per-CPU stop tasks:
84 */
85const struct sched_class stop_sched_class = {
86 .next = &rt_sched_class,
87
88 .enqueue_task = enqueue_task_stop,
89 .dequeue_task = dequeue_task_stop,
90 .yield_task = yield_task_stop,
91
92 .check_preempt_curr = check_preempt_curr_stop,
93
94 .pick_next_task = pick_next_task_stop,
95 .put_prev_task = put_prev_task_stop,
96
97#ifdef CONFIG_SMP
98 .select_task_rq = select_task_rq_stop,
99#endif
100
101 .set_curr_task = set_curr_task_stop,
102 .task_tick = task_tick_stop,
103
104 .get_rr_interval = get_rr_interval_stop,
105
106 .prio_changed = prio_changed_stop,
107 .switched_to = switched_to_stop,
108};