diff options
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r-- | kernel/workqueue.c | 3177 |
1 files changed, 2771 insertions, 406 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 327d2deb4451..2994a0e3a61c 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c | |||
@@ -33,41 +33,287 @@ | |||
33 | #include <linux/kallsyms.h> | 33 | #include <linux/kallsyms.h> |
34 | #include <linux/debug_locks.h> | 34 | #include <linux/debug_locks.h> |
35 | #include <linux/lockdep.h> | 35 | #include <linux/lockdep.h> |
36 | #define CREATE_TRACE_POINTS | 36 | #include <linux/idr.h> |
37 | #include <trace/events/workqueue.h> | 37 | |
38 | #include "workqueue_sched.h" | ||
39 | |||
40 | enum { | ||
41 | /* global_cwq flags */ | ||
42 | GCWQ_MANAGE_WORKERS = 1 << 0, /* need to manage workers */ | ||
43 | GCWQ_MANAGING_WORKERS = 1 << 1, /* managing workers */ | ||
44 | GCWQ_DISASSOCIATED = 1 << 2, /* cpu can't serve workers */ | ||
45 | GCWQ_FREEZING = 1 << 3, /* freeze in progress */ | ||
46 | GCWQ_HIGHPRI_PENDING = 1 << 4, /* highpri works on queue */ | ||
47 | |||
48 | /* worker flags */ | ||
49 | WORKER_STARTED = 1 << 0, /* started */ | ||
50 | WORKER_DIE = 1 << 1, /* die die die */ | ||
51 | WORKER_IDLE = 1 << 2, /* is idle */ | ||
52 | WORKER_PREP = 1 << 3, /* preparing to run works */ | ||
53 | WORKER_ROGUE = 1 << 4, /* not bound to any cpu */ | ||
54 | WORKER_REBIND = 1 << 5, /* mom is home, come back */ | ||
55 | WORKER_CPU_INTENSIVE = 1 << 6, /* cpu intensive */ | ||
56 | WORKER_UNBOUND = 1 << 7, /* worker is unbound */ | ||
57 | |||
58 | WORKER_NOT_RUNNING = WORKER_PREP | WORKER_ROGUE | WORKER_REBIND | | ||
59 | WORKER_CPU_INTENSIVE | WORKER_UNBOUND, | ||
60 | |||
61 | /* gcwq->trustee_state */ | ||
62 | TRUSTEE_START = 0, /* start */ | ||
63 | TRUSTEE_IN_CHARGE = 1, /* trustee in charge of gcwq */ | ||
64 | TRUSTEE_BUTCHER = 2, /* butcher workers */ | ||
65 | TRUSTEE_RELEASE = 3, /* release workers */ | ||
66 | TRUSTEE_DONE = 4, /* trustee is done */ | ||
67 | |||
68 | BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ | ||
69 | BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER, | ||
70 | BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1, | ||
71 | |||
72 | MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ | ||
73 | IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ | ||
74 | |||
75 | MAYDAY_INITIAL_TIMEOUT = HZ / 100, /* call for help after 10ms */ | ||
76 | MAYDAY_INTERVAL = HZ / 10, /* and then every 100ms */ | ||
77 | CREATE_COOLDOWN = HZ, /* time to breath after fail */ | ||
78 | TRUSTEE_COOLDOWN = HZ / 10, /* for trustee draining */ | ||
79 | |||
80 | /* | ||
81 | * Rescue workers are used only on emergencies and shared by | ||
82 | * all cpus. Give -20. | ||
83 | */ | ||
84 | RESCUER_NICE_LEVEL = -20, | ||
85 | }; | ||
38 | 86 | ||
39 | /* | 87 | /* |
40 | * The per-CPU workqueue (if single thread, we always use the first | 88 | * Structure fields follow one of the following exclusion rules. |
41 | * possible cpu). | 89 | * |
90 | * I: Set during initialization and read-only afterwards. | ||
91 | * | ||
92 | * P: Preemption protected. Disabling preemption is enough and should | ||
93 | * only be modified and accessed from the local cpu. | ||
94 | * | ||
95 | * L: gcwq->lock protected. Access with gcwq->lock held. | ||
96 | * | ||
97 | * X: During normal operation, modification requires gcwq->lock and | ||
98 | * should be done only from local cpu. Either disabling preemption | ||
99 | * on local cpu or grabbing gcwq->lock is enough for read access. | ||
100 | * If GCWQ_DISASSOCIATED is set, it's identical to L. | ||
101 | * | ||
102 | * F: wq->flush_mutex protected. | ||
103 | * | ||
104 | * W: workqueue_lock protected. | ||
42 | */ | 105 | */ |
43 | struct cpu_workqueue_struct { | ||
44 | 106 | ||
45 | spinlock_t lock; | 107 | struct global_cwq; |
46 | 108 | ||
47 | struct list_head worklist; | 109 | /* |
48 | wait_queue_head_t more_work; | 110 | * The poor guys doing the actual heavy lifting. All on-duty workers |
49 | struct work_struct *current_work; | 111 | * are either serving the manager role, on idle list or on busy hash. |
112 | */ | ||
113 | struct worker { | ||
114 | /* on idle list while idle, on busy hash table while busy */ | ||
115 | union { | ||
116 | struct list_head entry; /* L: while idle */ | ||
117 | struct hlist_node hentry; /* L: while busy */ | ||
118 | }; | ||
50 | 119 | ||
51 | struct workqueue_struct *wq; | 120 | struct work_struct *current_work; /* L: work being processed */ |
52 | struct task_struct *thread; | 121 | struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ |
53 | } ____cacheline_aligned; | 122 | struct list_head scheduled; /* L: scheduled works */ |
123 | struct task_struct *task; /* I: worker task */ | ||
124 | struct global_cwq *gcwq; /* I: the associated gcwq */ | ||
125 | /* 64 bytes boundary on 64bit, 32 on 32bit */ | ||
126 | unsigned long last_active; /* L: last active timestamp */ | ||
127 | unsigned int flags; /* X: flags */ | ||
128 | int id; /* I: worker id */ | ||
129 | struct work_struct rebind_work; /* L: rebind worker to cpu */ | ||
130 | }; | ||
131 | |||
132 | /* | ||
133 | * Global per-cpu workqueue. There's one and only one for each cpu | ||
134 | * and all works are queued and processed here regardless of their | ||
135 | * target workqueues. | ||
136 | */ | ||
137 | struct global_cwq { | ||
138 | spinlock_t lock; /* the gcwq lock */ | ||
139 | struct list_head worklist; /* L: list of pending works */ | ||
140 | unsigned int cpu; /* I: the associated cpu */ | ||
141 | unsigned int flags; /* L: GCWQ_* flags */ | ||
142 | |||
143 | int nr_workers; /* L: total number of workers */ | ||
144 | int nr_idle; /* L: currently idle ones */ | ||
145 | |||
146 | /* workers are chained either in the idle_list or busy_hash */ | ||
147 | struct list_head idle_list; /* X: list of idle workers */ | ||
148 | struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE]; | ||
149 | /* L: hash of busy workers */ | ||
150 | |||
151 | struct timer_list idle_timer; /* L: worker idle timeout */ | ||
152 | struct timer_list mayday_timer; /* L: SOS timer for dworkers */ | ||
153 | |||
154 | struct ida worker_ida; /* L: for worker IDs */ | ||
155 | |||
156 | struct task_struct *trustee; /* L: for gcwq shutdown */ | ||
157 | unsigned int trustee_state; /* L: trustee state */ | ||
158 | wait_queue_head_t trustee_wait; /* trustee wait */ | ||
159 | struct worker *first_idle; /* L: first idle worker */ | ||
160 | } ____cacheline_aligned_in_smp; | ||
161 | |||
162 | /* | ||
163 | * The per-CPU workqueue. The lower WORK_STRUCT_FLAG_BITS of | ||
164 | * work_struct->data are used for flags and thus cwqs need to be | ||
165 | * aligned at two's power of the number of flag bits. | ||
166 | */ | ||
167 | struct cpu_workqueue_struct { | ||
168 | struct global_cwq *gcwq; /* I: the associated gcwq */ | ||
169 | struct workqueue_struct *wq; /* I: the owning workqueue */ | ||
170 | int work_color; /* L: current color */ | ||
171 | int flush_color; /* L: flushing color */ | ||
172 | int nr_in_flight[WORK_NR_COLORS]; | ||
173 | /* L: nr of in_flight works */ | ||
174 | int nr_active; /* L: nr of active works */ | ||
175 | int max_active; /* L: max active works */ | ||
176 | struct list_head delayed_works; /* L: delayed works */ | ||
177 | }; | ||
178 | |||
179 | /* | ||
180 | * Structure used to wait for workqueue flush. | ||
181 | */ | ||
182 | struct wq_flusher { | ||
183 | struct list_head list; /* F: list of flushers */ | ||
184 | int flush_color; /* F: flush color waiting for */ | ||
185 | struct completion done; /* flush completion */ | ||
186 | }; | ||
187 | |||
188 | /* | ||
189 | * All cpumasks are assumed to be always set on UP and thus can't be | ||
190 | * used to determine whether there's something to be done. | ||
191 | */ | ||
192 | #ifdef CONFIG_SMP | ||
193 | typedef cpumask_var_t mayday_mask_t; | ||
194 | #define mayday_test_and_set_cpu(cpu, mask) \ | ||
195 | cpumask_test_and_set_cpu((cpu), (mask)) | ||
196 | #define mayday_clear_cpu(cpu, mask) cpumask_clear_cpu((cpu), (mask)) | ||
197 | #define for_each_mayday_cpu(cpu, mask) for_each_cpu((cpu), (mask)) | ||
198 | #define alloc_mayday_mask(maskp, gfp) alloc_cpumask_var((maskp), (gfp)) | ||
199 | #define free_mayday_mask(mask) free_cpumask_var((mask)) | ||
200 | #else | ||
201 | typedef unsigned long mayday_mask_t; | ||
202 | #define mayday_test_and_set_cpu(cpu, mask) test_and_set_bit(0, &(mask)) | ||
203 | #define mayday_clear_cpu(cpu, mask) clear_bit(0, &(mask)) | ||
204 | #define for_each_mayday_cpu(cpu, mask) if ((cpu) = 0, (mask)) | ||
205 | #define alloc_mayday_mask(maskp, gfp) true | ||
206 | #define free_mayday_mask(mask) do { } while (0) | ||
207 | #endif | ||
54 | 208 | ||
55 | /* | 209 | /* |
56 | * The externally visible workqueue abstraction is an array of | 210 | * The externally visible workqueue abstraction is an array of |
57 | * per-CPU workqueues: | 211 | * per-CPU workqueues: |
58 | */ | 212 | */ |
59 | struct workqueue_struct { | 213 | struct workqueue_struct { |
60 | struct cpu_workqueue_struct *cpu_wq; | 214 | unsigned int flags; /* I: WQ_* flags */ |
61 | struct list_head list; | 215 | union { |
62 | const char *name; | 216 | struct cpu_workqueue_struct __percpu *pcpu; |
63 | int singlethread; | 217 | struct cpu_workqueue_struct *single; |
64 | int freezeable; /* Freeze threads during suspend */ | 218 | unsigned long v; |
65 | int rt; | 219 | } cpu_wq; /* I: cwq's */ |
220 | struct list_head list; /* W: list of all workqueues */ | ||
221 | |||
222 | struct mutex flush_mutex; /* protects wq flushing */ | ||
223 | int work_color; /* F: current work color */ | ||
224 | int flush_color; /* F: current flush color */ | ||
225 | atomic_t nr_cwqs_to_flush; /* flush in progress */ | ||
226 | struct wq_flusher *first_flusher; /* F: first flusher */ | ||
227 | struct list_head flusher_queue; /* F: flush waiters */ | ||
228 | struct list_head flusher_overflow; /* F: flush overflow list */ | ||
229 | |||
230 | mayday_mask_t mayday_mask; /* cpus requesting rescue */ | ||
231 | struct worker *rescuer; /* I: rescue worker */ | ||
232 | |||
233 | int saved_max_active; /* W: saved cwq max_active */ | ||
234 | const char *name; /* I: workqueue name */ | ||
66 | #ifdef CONFIG_LOCKDEP | 235 | #ifdef CONFIG_LOCKDEP |
67 | struct lockdep_map lockdep_map; | 236 | struct lockdep_map lockdep_map; |
68 | #endif | 237 | #endif |
69 | }; | 238 | }; |
70 | 239 | ||
240 | struct workqueue_struct *system_wq __read_mostly; | ||
241 | struct workqueue_struct *system_long_wq __read_mostly; | ||
242 | struct workqueue_struct *system_nrt_wq __read_mostly; | ||
243 | struct workqueue_struct *system_unbound_wq __read_mostly; | ||
244 | EXPORT_SYMBOL_GPL(system_wq); | ||
245 | EXPORT_SYMBOL_GPL(system_long_wq); | ||
246 | EXPORT_SYMBOL_GPL(system_nrt_wq); | ||
247 | EXPORT_SYMBOL_GPL(system_unbound_wq); | ||
248 | |||
249 | #define for_each_busy_worker(worker, i, pos, gcwq) \ | ||
250 | for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \ | ||
251 | hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry) | ||
252 | |||
253 | static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask, | ||
254 | unsigned int sw) | ||
255 | { | ||
256 | if (cpu < nr_cpu_ids) { | ||
257 | if (sw & 1) { | ||
258 | cpu = cpumask_next(cpu, mask); | ||
259 | if (cpu < nr_cpu_ids) | ||
260 | return cpu; | ||
261 | } | ||
262 | if (sw & 2) | ||
263 | return WORK_CPU_UNBOUND; | ||
264 | } | ||
265 | return WORK_CPU_NONE; | ||
266 | } | ||
267 | |||
268 | static inline int __next_wq_cpu(int cpu, const struct cpumask *mask, | ||
269 | struct workqueue_struct *wq) | ||
270 | { | ||
271 | return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2); | ||
272 | } | ||
273 | |||
274 | /* | ||
275 | * CPU iterators | ||
276 | * | ||
277 | * An extra gcwq is defined for an invalid cpu number | ||
278 | * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any | ||
279 | * specific CPU. The following iterators are similar to | ||
280 | * for_each_*_cpu() iterators but also considers the unbound gcwq. | ||
281 | * | ||
282 | * for_each_gcwq_cpu() : possible CPUs + WORK_CPU_UNBOUND | ||
283 | * for_each_online_gcwq_cpu() : online CPUs + WORK_CPU_UNBOUND | ||
284 | * for_each_cwq_cpu() : possible CPUs for bound workqueues, | ||
285 | * WORK_CPU_UNBOUND for unbound workqueues | ||
286 | */ | ||
287 | #define for_each_gcwq_cpu(cpu) \ | ||
288 | for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3); \ | ||
289 | (cpu) < WORK_CPU_NONE; \ | ||
290 | (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3)) | ||
291 | |||
292 | #define for_each_online_gcwq_cpu(cpu) \ | ||
293 | for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3); \ | ||
294 | (cpu) < WORK_CPU_NONE; \ | ||
295 | (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3)) | ||
296 | |||
297 | #define for_each_cwq_cpu(cpu, wq) \ | ||
298 | for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq)); \ | ||
299 | (cpu) < WORK_CPU_NONE; \ | ||
300 | (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq))) | ||
301 | |||
302 | #ifdef CONFIG_LOCKDEP | ||
303 | /** | ||
304 | * in_workqueue_context() - in context of specified workqueue? | ||
305 | * @wq: the workqueue of interest | ||
306 | * | ||
307 | * Checks lockdep state to see if the current task is executing from | ||
308 | * within a workqueue item. This function exists only if lockdep is | ||
309 | * enabled. | ||
310 | */ | ||
311 | int in_workqueue_context(struct workqueue_struct *wq) | ||
312 | { | ||
313 | return lock_is_held(&wq->lockdep_map); | ||
314 | } | ||
315 | #endif | ||
316 | |||
71 | #ifdef CONFIG_DEBUG_OBJECTS_WORK | 317 | #ifdef CONFIG_DEBUG_OBJECTS_WORK |
72 | 318 | ||
73 | static struct debug_obj_descr work_debug_descr; | 319 | static struct debug_obj_descr work_debug_descr; |
@@ -107,7 +353,7 @@ static int work_fixup_activate(void *addr, enum debug_obj_state state) | |||
107 | * statically initialized. We just make sure that it | 353 | * statically initialized. We just make sure that it |
108 | * is tracked in the object tracker. | 354 | * is tracked in the object tracker. |
109 | */ | 355 | */ |
110 | if (test_bit(WORK_STRUCT_STATIC, work_data_bits(work))) { | 356 | if (test_bit(WORK_STRUCT_STATIC_BIT, work_data_bits(work))) { |
111 | debug_object_init(work, &work_debug_descr); | 357 | debug_object_init(work, &work_debug_descr); |
112 | debug_object_activate(work, &work_debug_descr); | 358 | debug_object_activate(work, &work_debug_descr); |
113 | return 0; | 359 | return 0; |
@@ -181,94 +427,575 @@ static inline void debug_work_deactivate(struct work_struct *work) { } | |||
181 | /* Serializes the accesses to the list of workqueues. */ | 427 | /* Serializes the accesses to the list of workqueues. */ |
182 | static DEFINE_SPINLOCK(workqueue_lock); | 428 | static DEFINE_SPINLOCK(workqueue_lock); |
183 | static LIST_HEAD(workqueues); | 429 | static LIST_HEAD(workqueues); |
430 | static bool workqueue_freezing; /* W: have wqs started freezing? */ | ||
431 | |||
432 | /* | ||
433 | * The almighty global cpu workqueues. nr_running is the only field | ||
434 | * which is expected to be used frequently by other cpus via | ||
435 | * try_to_wake_up(). Put it in a separate cacheline. | ||
436 | */ | ||
437 | static DEFINE_PER_CPU(struct global_cwq, global_cwq); | ||
438 | static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, gcwq_nr_running); | ||
184 | 439 | ||
185 | static int singlethread_cpu __read_mostly; | ||
186 | static const struct cpumask *cpu_singlethread_map __read_mostly; | ||
187 | /* | 440 | /* |
188 | * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD | 441 | * Global cpu workqueue and nr_running counter for unbound gcwq. The |
189 | * flushes cwq->worklist. This means that flush_workqueue/wait_on_work | 442 | * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its |
190 | * which comes in between can't use for_each_online_cpu(). We could | 443 | * workers have WORKER_UNBOUND set. |
191 | * use cpu_possible_map, the cpumask below is more a documentation | ||
192 | * than optimization. | ||
193 | */ | 444 | */ |
194 | static cpumask_var_t cpu_populated_map __read_mostly; | 445 | static struct global_cwq unbound_global_cwq; |
446 | static atomic_t unbound_gcwq_nr_running = ATOMIC_INIT(0); /* always 0 */ | ||
195 | 447 | ||
196 | /* If it's single threaded, it isn't in the list of workqueues. */ | 448 | static int worker_thread(void *__worker); |
197 | static inline int is_wq_single_threaded(struct workqueue_struct *wq) | 449 | |
450 | static struct global_cwq *get_gcwq(unsigned int cpu) | ||
198 | { | 451 | { |
199 | return wq->singlethread; | 452 | if (cpu != WORK_CPU_UNBOUND) |
453 | return &per_cpu(global_cwq, cpu); | ||
454 | else | ||
455 | return &unbound_global_cwq; | ||
200 | } | 456 | } |
201 | 457 | ||
202 | static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq) | 458 | static atomic_t *get_gcwq_nr_running(unsigned int cpu) |
203 | { | 459 | { |
204 | return is_wq_single_threaded(wq) | 460 | if (cpu != WORK_CPU_UNBOUND) |
205 | ? cpu_singlethread_map : cpu_populated_map; | 461 | return &per_cpu(gcwq_nr_running, cpu); |
462 | else | ||
463 | return &unbound_gcwq_nr_running; | ||
206 | } | 464 | } |
207 | 465 | ||
208 | static | 466 | static struct cpu_workqueue_struct *get_cwq(unsigned int cpu, |
209 | struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu) | 467 | struct workqueue_struct *wq) |
210 | { | 468 | { |
211 | if (unlikely(is_wq_single_threaded(wq))) | 469 | if (!(wq->flags & WQ_UNBOUND)) { |
212 | cpu = singlethread_cpu; | 470 | if (likely(cpu < nr_cpu_ids)) { |
213 | return per_cpu_ptr(wq->cpu_wq, cpu); | 471 | #ifdef CONFIG_SMP |
472 | return per_cpu_ptr(wq->cpu_wq.pcpu, cpu); | ||
473 | #else | ||
474 | return wq->cpu_wq.single; | ||
475 | #endif | ||
476 | } | ||
477 | } else if (likely(cpu == WORK_CPU_UNBOUND)) | ||
478 | return wq->cpu_wq.single; | ||
479 | return NULL; | ||
480 | } | ||
481 | |||
482 | static unsigned int work_color_to_flags(int color) | ||
483 | { | ||
484 | return color << WORK_STRUCT_COLOR_SHIFT; | ||
485 | } | ||
486 | |||
487 | static int get_work_color(struct work_struct *work) | ||
488 | { | ||
489 | return (*work_data_bits(work) >> WORK_STRUCT_COLOR_SHIFT) & | ||
490 | ((1 << WORK_STRUCT_COLOR_BITS) - 1); | ||
491 | } | ||
492 | |||
493 | static int work_next_color(int color) | ||
494 | { | ||
495 | return (color + 1) % WORK_NR_COLORS; | ||
214 | } | 496 | } |
215 | 497 | ||
216 | /* | 498 | /* |
217 | * Set the workqueue on which a work item is to be run | 499 | * A work's data points to the cwq with WORK_STRUCT_CWQ set while the |
218 | * - Must *only* be called if the pending flag is set | 500 | * work is on queue. Once execution starts, WORK_STRUCT_CWQ is |
501 | * cleared and the work data contains the cpu number it was last on. | ||
502 | * | ||
503 | * set_work_{cwq|cpu}() and clear_work_data() can be used to set the | ||
504 | * cwq, cpu or clear work->data. These functions should only be | ||
505 | * called while the work is owned - ie. while the PENDING bit is set. | ||
506 | * | ||
507 | * get_work_[g]cwq() can be used to obtain the gcwq or cwq | ||
508 | * corresponding to a work. gcwq is available once the work has been | ||
509 | * queued anywhere after initialization. cwq is available only from | ||
510 | * queueing until execution starts. | ||
219 | */ | 511 | */ |
220 | static inline void set_wq_data(struct work_struct *work, | 512 | static inline void set_work_data(struct work_struct *work, unsigned long data, |
221 | struct cpu_workqueue_struct *cwq) | 513 | unsigned long flags) |
222 | { | 514 | { |
223 | unsigned long new; | ||
224 | |||
225 | BUG_ON(!work_pending(work)); | 515 | BUG_ON(!work_pending(work)); |
516 | atomic_long_set(&work->data, data | flags | work_static(work)); | ||
517 | } | ||
518 | |||
519 | static void set_work_cwq(struct work_struct *work, | ||
520 | struct cpu_workqueue_struct *cwq, | ||
521 | unsigned long extra_flags) | ||
522 | { | ||
523 | set_work_data(work, (unsigned long)cwq, | ||
524 | WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags); | ||
525 | } | ||
526 | |||
527 | static void set_work_cpu(struct work_struct *work, unsigned int cpu) | ||
528 | { | ||
529 | set_work_data(work, cpu << WORK_STRUCT_FLAG_BITS, WORK_STRUCT_PENDING); | ||
530 | } | ||
531 | |||
532 | static void clear_work_data(struct work_struct *work) | ||
533 | { | ||
534 | set_work_data(work, WORK_STRUCT_NO_CPU, 0); | ||
535 | } | ||
536 | |||
537 | static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work) | ||
538 | { | ||
539 | unsigned long data = atomic_long_read(&work->data); | ||
540 | |||
541 | if (data & WORK_STRUCT_CWQ) | ||
542 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); | ||
543 | else | ||
544 | return NULL; | ||
545 | } | ||
546 | |||
547 | static struct global_cwq *get_work_gcwq(struct work_struct *work) | ||
548 | { | ||
549 | unsigned long data = atomic_long_read(&work->data); | ||
550 | unsigned int cpu; | ||
551 | |||
552 | if (data & WORK_STRUCT_CWQ) | ||
553 | return ((struct cpu_workqueue_struct *) | ||
554 | (data & WORK_STRUCT_WQ_DATA_MASK))->gcwq; | ||
555 | |||
556 | cpu = data >> WORK_STRUCT_FLAG_BITS; | ||
557 | if (cpu == WORK_CPU_NONE) | ||
558 | return NULL; | ||
559 | |||
560 | BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND); | ||
561 | return get_gcwq(cpu); | ||
562 | } | ||
563 | |||
564 | /* | ||
565 | * Policy functions. These define the policies on how the global | ||
566 | * worker pool is managed. Unless noted otherwise, these functions | ||
567 | * assume that they're being called with gcwq->lock held. | ||
568 | */ | ||
569 | |||
570 | static bool __need_more_worker(struct global_cwq *gcwq) | ||
571 | { | ||
572 | return !atomic_read(get_gcwq_nr_running(gcwq->cpu)) || | ||
573 | gcwq->flags & GCWQ_HIGHPRI_PENDING; | ||
574 | } | ||
575 | |||
576 | /* | ||
577 | * Need to wake up a worker? Called from anything but currently | ||
578 | * running workers. | ||
579 | */ | ||
580 | static bool need_more_worker(struct global_cwq *gcwq) | ||
581 | { | ||
582 | return !list_empty(&gcwq->worklist) && __need_more_worker(gcwq); | ||
583 | } | ||
584 | |||
585 | /* Can I start working? Called from busy but !running workers. */ | ||
586 | static bool may_start_working(struct global_cwq *gcwq) | ||
587 | { | ||
588 | return gcwq->nr_idle; | ||
589 | } | ||
590 | |||
591 | /* Do I need to keep working? Called from currently running workers. */ | ||
592 | static bool keep_working(struct global_cwq *gcwq) | ||
593 | { | ||
594 | atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu); | ||
595 | |||
596 | return !list_empty(&gcwq->worklist) && atomic_read(nr_running) <= 1; | ||
597 | } | ||
598 | |||
599 | /* Do we need a new worker? Called from manager. */ | ||
600 | static bool need_to_create_worker(struct global_cwq *gcwq) | ||
601 | { | ||
602 | return need_more_worker(gcwq) && !may_start_working(gcwq); | ||
603 | } | ||
604 | |||
605 | /* Do I need to be the manager? */ | ||
606 | static bool need_to_manage_workers(struct global_cwq *gcwq) | ||
607 | { | ||
608 | return need_to_create_worker(gcwq) || gcwq->flags & GCWQ_MANAGE_WORKERS; | ||
609 | } | ||
610 | |||
611 | /* Do we have too many workers and should some go away? */ | ||
612 | static bool too_many_workers(struct global_cwq *gcwq) | ||
613 | { | ||
614 | bool managing = gcwq->flags & GCWQ_MANAGING_WORKERS; | ||
615 | int nr_idle = gcwq->nr_idle + managing; /* manager is considered idle */ | ||
616 | int nr_busy = gcwq->nr_workers - nr_idle; | ||
226 | 617 | ||
227 | new = (unsigned long) cwq | (1UL << WORK_STRUCT_PENDING); | 618 | return nr_idle > 2 && (nr_idle - 2) * MAX_IDLE_WORKERS_RATIO >= nr_busy; |
228 | new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); | ||
229 | atomic_long_set(&work->data, new); | ||
230 | } | 619 | } |
231 | 620 | ||
232 | /* | 621 | /* |
233 | * Clear WORK_STRUCT_PENDING and the workqueue on which it was queued. | 622 | * Wake up functions. |
234 | */ | 623 | */ |
235 | static inline void clear_wq_data(struct work_struct *work) | 624 | |
625 | /* Return the first worker. Safe with preemption disabled */ | ||
626 | static struct worker *first_worker(struct global_cwq *gcwq) | ||
236 | { | 627 | { |
237 | unsigned long flags = *work_data_bits(work) & | 628 | if (unlikely(list_empty(&gcwq->idle_list))) |
238 | (1UL << WORK_STRUCT_STATIC); | 629 | return NULL; |
239 | atomic_long_set(&work->data, flags); | 630 | |
631 | return list_first_entry(&gcwq->idle_list, struct worker, entry); | ||
240 | } | 632 | } |
241 | 633 | ||
242 | static inline | 634 | /** |
243 | struct cpu_workqueue_struct *get_wq_data(struct work_struct *work) | 635 | * wake_up_worker - wake up an idle worker |
636 | * @gcwq: gcwq to wake worker for | ||
637 | * | ||
638 | * Wake up the first idle worker of @gcwq. | ||
639 | * | ||
640 | * CONTEXT: | ||
641 | * spin_lock_irq(gcwq->lock). | ||
642 | */ | ||
643 | static void wake_up_worker(struct global_cwq *gcwq) | ||
244 | { | 644 | { |
245 | return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); | 645 | struct worker *worker = first_worker(gcwq); |
646 | |||
647 | if (likely(worker)) | ||
648 | wake_up_process(worker->task); | ||
649 | } | ||
650 | |||
651 | /** | ||
652 | * wq_worker_waking_up - a worker is waking up | ||
653 | * @task: task waking up | ||
654 | * @cpu: CPU @task is waking up to | ||
655 | * | ||
656 | * This function is called during try_to_wake_up() when a worker is | ||
657 | * being awoken. | ||
658 | * | ||
659 | * CONTEXT: | ||
660 | * spin_lock_irq(rq->lock) | ||
661 | */ | ||
662 | void wq_worker_waking_up(struct task_struct *task, unsigned int cpu) | ||
663 | { | ||
664 | struct worker *worker = kthread_data(task); | ||
665 | |||
666 | if (likely(!(worker->flags & WORKER_NOT_RUNNING))) | ||
667 | atomic_inc(get_gcwq_nr_running(cpu)); | ||
668 | } | ||
669 | |||
670 | /** | ||
671 | * wq_worker_sleeping - a worker is going to sleep | ||
672 | * @task: task going to sleep | ||
673 | * @cpu: CPU in question, must be the current CPU number | ||
674 | * | ||
675 | * This function is called during schedule() when a busy worker is | ||
676 | * going to sleep. Worker on the same cpu can be woken up by | ||
677 | * returning pointer to its task. | ||
678 | * | ||
679 | * CONTEXT: | ||
680 | * spin_lock_irq(rq->lock) | ||
681 | * | ||
682 | * RETURNS: | ||
683 | * Worker task on @cpu to wake up, %NULL if none. | ||
684 | */ | ||
685 | struct task_struct *wq_worker_sleeping(struct task_struct *task, | ||
686 | unsigned int cpu) | ||
687 | { | ||
688 | struct worker *worker = kthread_data(task), *to_wakeup = NULL; | ||
689 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
690 | atomic_t *nr_running = get_gcwq_nr_running(cpu); | ||
691 | |||
692 | if (unlikely(worker->flags & WORKER_NOT_RUNNING)) | ||
693 | return NULL; | ||
694 | |||
695 | /* this can only happen on the local cpu */ | ||
696 | BUG_ON(cpu != raw_smp_processor_id()); | ||
697 | |||
698 | /* | ||
699 | * The counterpart of the following dec_and_test, implied mb, | ||
700 | * worklist not empty test sequence is in insert_work(). | ||
701 | * Please read comment there. | ||
702 | * | ||
703 | * NOT_RUNNING is clear. This means that trustee is not in | ||
704 | * charge and we're running on the local cpu w/ rq lock held | ||
705 | * and preemption disabled, which in turn means that none else | ||
706 | * could be manipulating idle_list, so dereferencing idle_list | ||
707 | * without gcwq lock is safe. | ||
708 | */ | ||
709 | if (atomic_dec_and_test(nr_running) && !list_empty(&gcwq->worklist)) | ||
710 | to_wakeup = first_worker(gcwq); | ||
711 | return to_wakeup ? to_wakeup->task : NULL; | ||
712 | } | ||
713 | |||
714 | /** | ||
715 | * worker_set_flags - set worker flags and adjust nr_running accordingly | ||
716 | * @worker: self | ||
717 | * @flags: flags to set | ||
718 | * @wakeup: wakeup an idle worker if necessary | ||
719 | * | ||
720 | * Set @flags in @worker->flags and adjust nr_running accordingly. If | ||
721 | * nr_running becomes zero and @wakeup is %true, an idle worker is | ||
722 | * woken up. | ||
723 | * | ||
724 | * CONTEXT: | ||
725 | * spin_lock_irq(gcwq->lock) | ||
726 | */ | ||
727 | static inline void worker_set_flags(struct worker *worker, unsigned int flags, | ||
728 | bool wakeup) | ||
729 | { | ||
730 | struct global_cwq *gcwq = worker->gcwq; | ||
731 | |||
732 | WARN_ON_ONCE(worker->task != current); | ||
733 | |||
734 | /* | ||
735 | * If transitioning into NOT_RUNNING, adjust nr_running and | ||
736 | * wake up an idle worker as necessary if requested by | ||
737 | * @wakeup. | ||
738 | */ | ||
739 | if ((flags & WORKER_NOT_RUNNING) && | ||
740 | !(worker->flags & WORKER_NOT_RUNNING)) { | ||
741 | atomic_t *nr_running = get_gcwq_nr_running(gcwq->cpu); | ||
742 | |||
743 | if (wakeup) { | ||
744 | if (atomic_dec_and_test(nr_running) && | ||
745 | !list_empty(&gcwq->worklist)) | ||
746 | wake_up_worker(gcwq); | ||
747 | } else | ||
748 | atomic_dec(nr_running); | ||
749 | } | ||
750 | |||
751 | worker->flags |= flags; | ||
246 | } | 752 | } |
247 | 753 | ||
754 | /** | ||
755 | * worker_clr_flags - clear worker flags and adjust nr_running accordingly | ||
756 | * @worker: self | ||
757 | * @flags: flags to clear | ||
758 | * | ||
759 | * Clear @flags in @worker->flags and adjust nr_running accordingly. | ||
760 | * | ||
761 | * CONTEXT: | ||
762 | * spin_lock_irq(gcwq->lock) | ||
763 | */ | ||
764 | static inline void worker_clr_flags(struct worker *worker, unsigned int flags) | ||
765 | { | ||
766 | struct global_cwq *gcwq = worker->gcwq; | ||
767 | unsigned int oflags = worker->flags; | ||
768 | |||
769 | WARN_ON_ONCE(worker->task != current); | ||
770 | |||
771 | worker->flags &= ~flags; | ||
772 | |||
773 | /* if transitioning out of NOT_RUNNING, increment nr_running */ | ||
774 | if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING)) | ||
775 | if (!(worker->flags & WORKER_NOT_RUNNING)) | ||
776 | atomic_inc(get_gcwq_nr_running(gcwq->cpu)); | ||
777 | } | ||
778 | |||
779 | /** | ||
780 | * busy_worker_head - return the busy hash head for a work | ||
781 | * @gcwq: gcwq of interest | ||
782 | * @work: work to be hashed | ||
783 | * | ||
784 | * Return hash head of @gcwq for @work. | ||
785 | * | ||
786 | * CONTEXT: | ||
787 | * spin_lock_irq(gcwq->lock). | ||
788 | * | ||
789 | * RETURNS: | ||
790 | * Pointer to the hash head. | ||
791 | */ | ||
792 | static struct hlist_head *busy_worker_head(struct global_cwq *gcwq, | ||
793 | struct work_struct *work) | ||
794 | { | ||
795 | const int base_shift = ilog2(sizeof(struct work_struct)); | ||
796 | unsigned long v = (unsigned long)work; | ||
797 | |||
798 | /* simple shift and fold hash, do we need something better? */ | ||
799 | v >>= base_shift; | ||
800 | v += v >> BUSY_WORKER_HASH_ORDER; | ||
801 | v &= BUSY_WORKER_HASH_MASK; | ||
802 | |||
803 | return &gcwq->busy_hash[v]; | ||
804 | } | ||
805 | |||
806 | /** | ||
807 | * __find_worker_executing_work - find worker which is executing a work | ||
808 | * @gcwq: gcwq of interest | ||
809 | * @bwh: hash head as returned by busy_worker_head() | ||
810 | * @work: work to find worker for | ||
811 | * | ||
812 | * Find a worker which is executing @work on @gcwq. @bwh should be | ||
813 | * the hash head obtained by calling busy_worker_head() with the same | ||
814 | * work. | ||
815 | * | ||
816 | * CONTEXT: | ||
817 | * spin_lock_irq(gcwq->lock). | ||
818 | * | ||
819 | * RETURNS: | ||
820 | * Pointer to worker which is executing @work if found, NULL | ||
821 | * otherwise. | ||
822 | */ | ||
823 | static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, | ||
824 | struct hlist_head *bwh, | ||
825 | struct work_struct *work) | ||
826 | { | ||
827 | struct worker *worker; | ||
828 | struct hlist_node *tmp; | ||
829 | |||
830 | hlist_for_each_entry(worker, tmp, bwh, hentry) | ||
831 | if (worker->current_work == work) | ||
832 | return worker; | ||
833 | return NULL; | ||
834 | } | ||
835 | |||
836 | /** | ||
837 | * find_worker_executing_work - find worker which is executing a work | ||
838 | * @gcwq: gcwq of interest | ||
839 | * @work: work to find worker for | ||
840 | * | ||
841 | * Find a worker which is executing @work on @gcwq. This function is | ||
842 | * identical to __find_worker_executing_work() except that this | ||
843 | * function calculates @bwh itself. | ||
844 | * | ||
845 | * CONTEXT: | ||
846 | * spin_lock_irq(gcwq->lock). | ||
847 | * | ||
848 | * RETURNS: | ||
849 | * Pointer to worker which is executing @work if found, NULL | ||
850 | * otherwise. | ||
851 | */ | ||
852 | static struct worker *find_worker_executing_work(struct global_cwq *gcwq, | ||
853 | struct work_struct *work) | ||
854 | { | ||
855 | return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work), | ||
856 | work); | ||
857 | } | ||
858 | |||
859 | /** | ||
860 | * gcwq_determine_ins_pos - find insertion position | ||
861 | * @gcwq: gcwq of interest | ||
862 | * @cwq: cwq a work is being queued for | ||
863 | * | ||
864 | * A work for @cwq is about to be queued on @gcwq, determine insertion | ||
865 | * position for the work. If @cwq is for HIGHPRI wq, the work is | ||
866 | * queued at the head of the queue but in FIFO order with respect to | ||
867 | * other HIGHPRI works; otherwise, at the end of the queue. This | ||
868 | * function also sets GCWQ_HIGHPRI_PENDING flag to hint @gcwq that | ||
869 | * there are HIGHPRI works pending. | ||
870 | * | ||
871 | * CONTEXT: | ||
872 | * spin_lock_irq(gcwq->lock). | ||
873 | * | ||
874 | * RETURNS: | ||
875 | * Pointer to inserstion position. | ||
876 | */ | ||
877 | static inline struct list_head *gcwq_determine_ins_pos(struct global_cwq *gcwq, | ||
878 | struct cpu_workqueue_struct *cwq) | ||
879 | { | ||
880 | struct work_struct *twork; | ||
881 | |||
882 | if (likely(!(cwq->wq->flags & WQ_HIGHPRI))) | ||
883 | return &gcwq->worklist; | ||
884 | |||
885 | list_for_each_entry(twork, &gcwq->worklist, entry) { | ||
886 | struct cpu_workqueue_struct *tcwq = get_work_cwq(twork); | ||
887 | |||
888 | if (!(tcwq->wq->flags & WQ_HIGHPRI)) | ||
889 | break; | ||
890 | } | ||
891 | |||
892 | gcwq->flags |= GCWQ_HIGHPRI_PENDING; | ||
893 | return &twork->entry; | ||
894 | } | ||
895 | |||
896 | /** | ||
897 | * insert_work - insert a work into gcwq | ||
898 | * @cwq: cwq @work belongs to | ||
899 | * @work: work to insert | ||
900 | * @head: insertion point | ||
901 | * @extra_flags: extra WORK_STRUCT_* flags to set | ||
902 | * | ||
903 | * Insert @work which belongs to @cwq into @gcwq after @head. | ||
904 | * @extra_flags is or'd to work_struct flags. | ||
905 | * | ||
906 | * CONTEXT: | ||
907 | * spin_lock_irq(gcwq->lock). | ||
908 | */ | ||
248 | static void insert_work(struct cpu_workqueue_struct *cwq, | 909 | static void insert_work(struct cpu_workqueue_struct *cwq, |
249 | struct work_struct *work, struct list_head *head) | 910 | struct work_struct *work, struct list_head *head, |
911 | unsigned int extra_flags) | ||
250 | { | 912 | { |
251 | trace_workqueue_insertion(cwq->thread, work); | 913 | struct global_cwq *gcwq = cwq->gcwq; |
914 | |||
915 | /* we own @work, set data and link */ | ||
916 | set_work_cwq(work, cwq, extra_flags); | ||
252 | 917 | ||
253 | set_wq_data(work, cwq); | ||
254 | /* | 918 | /* |
255 | * Ensure that we get the right work->data if we see the | 919 | * Ensure that we get the right work->data if we see the |
256 | * result of list_add() below, see try_to_grab_pending(). | 920 | * result of list_add() below, see try_to_grab_pending(). |
257 | */ | 921 | */ |
258 | smp_wmb(); | 922 | smp_wmb(); |
923 | |||
259 | list_add_tail(&work->entry, head); | 924 | list_add_tail(&work->entry, head); |
260 | wake_up(&cwq->more_work); | 925 | |
926 | /* | ||
927 | * Ensure either worker_sched_deactivated() sees the above | ||
928 | * list_add_tail() or we see zero nr_running to avoid workers | ||
929 | * lying around lazily while there are works to be processed. | ||
930 | */ | ||
931 | smp_mb(); | ||
932 | |||
933 | if (__need_more_worker(gcwq)) | ||
934 | wake_up_worker(gcwq); | ||
261 | } | 935 | } |
262 | 936 | ||
263 | static void __queue_work(struct cpu_workqueue_struct *cwq, | 937 | static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, |
264 | struct work_struct *work) | 938 | struct work_struct *work) |
265 | { | 939 | { |
940 | struct global_cwq *gcwq; | ||
941 | struct cpu_workqueue_struct *cwq; | ||
942 | struct list_head *worklist; | ||
266 | unsigned long flags; | 943 | unsigned long flags; |
267 | 944 | ||
268 | debug_work_activate(work); | 945 | debug_work_activate(work); |
269 | spin_lock_irqsave(&cwq->lock, flags); | 946 | |
270 | insert_work(cwq, work, &cwq->worklist); | 947 | /* determine gcwq to use */ |
271 | spin_unlock_irqrestore(&cwq->lock, flags); | 948 | if (!(wq->flags & WQ_UNBOUND)) { |
949 | struct global_cwq *last_gcwq; | ||
950 | |||
951 | if (unlikely(cpu == WORK_CPU_UNBOUND)) | ||
952 | cpu = raw_smp_processor_id(); | ||
953 | |||
954 | /* | ||
955 | * It's multi cpu. If @wq is non-reentrant and @work | ||
956 | * was previously on a different cpu, it might still | ||
957 | * be running there, in which case the work needs to | ||
958 | * be queued on that cpu to guarantee non-reentrance. | ||
959 | */ | ||
960 | gcwq = get_gcwq(cpu); | ||
961 | if (wq->flags & WQ_NON_REENTRANT && | ||
962 | (last_gcwq = get_work_gcwq(work)) && last_gcwq != gcwq) { | ||
963 | struct worker *worker; | ||
964 | |||
965 | spin_lock_irqsave(&last_gcwq->lock, flags); | ||
966 | |||
967 | worker = find_worker_executing_work(last_gcwq, work); | ||
968 | |||
969 | if (worker && worker->current_cwq->wq == wq) | ||
970 | gcwq = last_gcwq; | ||
971 | else { | ||
972 | /* meh... not running there, queue here */ | ||
973 | spin_unlock_irqrestore(&last_gcwq->lock, flags); | ||
974 | spin_lock_irqsave(&gcwq->lock, flags); | ||
975 | } | ||
976 | } else | ||
977 | spin_lock_irqsave(&gcwq->lock, flags); | ||
978 | } else { | ||
979 | gcwq = get_gcwq(WORK_CPU_UNBOUND); | ||
980 | spin_lock_irqsave(&gcwq->lock, flags); | ||
981 | } | ||
982 | |||
983 | /* gcwq determined, get cwq and queue */ | ||
984 | cwq = get_cwq(gcwq->cpu, wq); | ||
985 | |||
986 | BUG_ON(!list_empty(&work->entry)); | ||
987 | |||
988 | cwq->nr_in_flight[cwq->work_color]++; | ||
989 | |||
990 | if (likely(cwq->nr_active < cwq->max_active)) { | ||
991 | cwq->nr_active++; | ||
992 | worklist = gcwq_determine_ins_pos(gcwq, cwq); | ||
993 | } else | ||
994 | worklist = &cwq->delayed_works; | ||
995 | |||
996 | insert_work(cwq, work, worklist, work_color_to_flags(cwq->work_color)); | ||
997 | |||
998 | spin_unlock_irqrestore(&gcwq->lock, flags); | ||
272 | } | 999 | } |
273 | 1000 | ||
274 | /** | 1001 | /** |
@@ -308,9 +1035,8 @@ queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work) | |||
308 | { | 1035 | { |
309 | int ret = 0; | 1036 | int ret = 0; |
310 | 1037 | ||
311 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | 1038 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
312 | BUG_ON(!list_empty(&work->entry)); | 1039 | __queue_work(cpu, wq, work); |
313 | __queue_work(wq_per_cpu(wq, cpu), work); | ||
314 | ret = 1; | 1040 | ret = 1; |
315 | } | 1041 | } |
316 | return ret; | 1042 | return ret; |
@@ -320,10 +1046,9 @@ EXPORT_SYMBOL_GPL(queue_work_on); | |||
320 | static void delayed_work_timer_fn(unsigned long __data) | 1046 | static void delayed_work_timer_fn(unsigned long __data) |
321 | { | 1047 | { |
322 | struct delayed_work *dwork = (struct delayed_work *)__data; | 1048 | struct delayed_work *dwork = (struct delayed_work *)__data; |
323 | struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work); | 1049 | struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work); |
324 | struct workqueue_struct *wq = cwq->wq; | ||
325 | 1050 | ||
326 | __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work); | 1051 | __queue_work(smp_processor_id(), cwq->wq, &dwork->work); |
327 | } | 1052 | } |
328 | 1053 | ||
329 | /** | 1054 | /** |
@@ -360,14 +1085,31 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, | |||
360 | struct timer_list *timer = &dwork->timer; | 1085 | struct timer_list *timer = &dwork->timer; |
361 | struct work_struct *work = &dwork->work; | 1086 | struct work_struct *work = &dwork->work; |
362 | 1087 | ||
363 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { | 1088 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { |
1089 | unsigned int lcpu; | ||
1090 | |||
364 | BUG_ON(timer_pending(timer)); | 1091 | BUG_ON(timer_pending(timer)); |
365 | BUG_ON(!list_empty(&work->entry)); | 1092 | BUG_ON(!list_empty(&work->entry)); |
366 | 1093 | ||
367 | timer_stats_timer_set_start_info(&dwork->timer); | 1094 | timer_stats_timer_set_start_info(&dwork->timer); |
368 | 1095 | ||
369 | /* This stores cwq for the moment, for the timer_fn */ | 1096 | /* |
370 | set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id())); | 1097 | * This stores cwq for the moment, for the timer_fn. |
1098 | * Note that the work's gcwq is preserved to allow | ||
1099 | * reentrance detection for delayed works. | ||
1100 | */ | ||
1101 | if (!(wq->flags & WQ_UNBOUND)) { | ||
1102 | struct global_cwq *gcwq = get_work_gcwq(work); | ||
1103 | |||
1104 | if (gcwq && gcwq->cpu != WORK_CPU_UNBOUND) | ||
1105 | lcpu = gcwq->cpu; | ||
1106 | else | ||
1107 | lcpu = raw_smp_processor_id(); | ||
1108 | } else | ||
1109 | lcpu = WORK_CPU_UNBOUND; | ||
1110 | |||
1111 | set_work_cwq(work, get_cwq(lcpu, wq), 0); | ||
1112 | |||
371 | timer->expires = jiffies + delay; | 1113 | timer->expires = jiffies + delay; |
372 | timer->data = (unsigned long)dwork; | 1114 | timer->data = (unsigned long)dwork; |
373 | timer->function = delayed_work_timer_fn; | 1115 | timer->function = delayed_work_timer_fn; |
@@ -382,80 +1124,872 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, | |||
382 | } | 1124 | } |
383 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); | 1125 | EXPORT_SYMBOL_GPL(queue_delayed_work_on); |
384 | 1126 | ||
385 | static void run_workqueue(struct cpu_workqueue_struct *cwq) | 1127 | /** |
1128 | * worker_enter_idle - enter idle state | ||
1129 | * @worker: worker which is entering idle state | ||
1130 | * | ||
1131 | * @worker is entering idle state. Update stats and idle timer if | ||
1132 | * necessary. | ||
1133 | * | ||
1134 | * LOCKING: | ||
1135 | * spin_lock_irq(gcwq->lock). | ||
1136 | */ | ||
1137 | static void worker_enter_idle(struct worker *worker) | ||
386 | { | 1138 | { |
387 | spin_lock_irq(&cwq->lock); | 1139 | struct global_cwq *gcwq = worker->gcwq; |
388 | while (!list_empty(&cwq->worklist)) { | 1140 | |
389 | struct work_struct *work = list_entry(cwq->worklist.next, | 1141 | BUG_ON(worker->flags & WORKER_IDLE); |
390 | struct work_struct, entry); | 1142 | BUG_ON(!list_empty(&worker->entry) && |
391 | work_func_t f = work->func; | 1143 | (worker->hentry.next || worker->hentry.pprev)); |
392 | #ifdef CONFIG_LOCKDEP | 1144 | |
1145 | /* can't use worker_set_flags(), also called from start_worker() */ | ||
1146 | worker->flags |= WORKER_IDLE; | ||
1147 | gcwq->nr_idle++; | ||
1148 | worker->last_active = jiffies; | ||
1149 | |||
1150 | /* idle_list is LIFO */ | ||
1151 | list_add(&worker->entry, &gcwq->idle_list); | ||
1152 | |||
1153 | if (likely(!(worker->flags & WORKER_ROGUE))) { | ||
1154 | if (too_many_workers(gcwq) && !timer_pending(&gcwq->idle_timer)) | ||
1155 | mod_timer(&gcwq->idle_timer, | ||
1156 | jiffies + IDLE_WORKER_TIMEOUT); | ||
1157 | } else | ||
1158 | wake_up_all(&gcwq->trustee_wait); | ||
1159 | |||
1160 | /* sanity check nr_running */ | ||
1161 | WARN_ON_ONCE(gcwq->nr_workers == gcwq->nr_idle && | ||
1162 | atomic_read(get_gcwq_nr_running(gcwq->cpu))); | ||
1163 | } | ||
1164 | |||
1165 | /** | ||
1166 | * worker_leave_idle - leave idle state | ||
1167 | * @worker: worker which is leaving idle state | ||
1168 | * | ||
1169 | * @worker is leaving idle state. Update stats. | ||
1170 | * | ||
1171 | * LOCKING: | ||
1172 | * spin_lock_irq(gcwq->lock). | ||
1173 | */ | ||
1174 | static void worker_leave_idle(struct worker *worker) | ||
1175 | { | ||
1176 | struct global_cwq *gcwq = worker->gcwq; | ||
1177 | |||
1178 | BUG_ON(!(worker->flags & WORKER_IDLE)); | ||
1179 | worker_clr_flags(worker, WORKER_IDLE); | ||
1180 | gcwq->nr_idle--; | ||
1181 | list_del_init(&worker->entry); | ||
1182 | } | ||
1183 | |||
1184 | /** | ||
1185 | * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq | ||
1186 | * @worker: self | ||
1187 | * | ||
1188 | * Works which are scheduled while the cpu is online must at least be | ||
1189 | * scheduled to a worker which is bound to the cpu so that if they are | ||
1190 | * flushed from cpu callbacks while cpu is going down, they are | ||
1191 | * guaranteed to execute on the cpu. | ||
1192 | * | ||
1193 | * This function is to be used by rogue workers and rescuers to bind | ||
1194 | * themselves to the target cpu and may race with cpu going down or | ||
1195 | * coming online. kthread_bind() can't be used because it may put the | ||
1196 | * worker to already dead cpu and set_cpus_allowed_ptr() can't be used | ||
1197 | * verbatim as it's best effort and blocking and gcwq may be | ||
1198 | * [dis]associated in the meantime. | ||
1199 | * | ||
1200 | * This function tries set_cpus_allowed() and locks gcwq and verifies | ||
1201 | * the binding against GCWQ_DISASSOCIATED which is set during | ||
1202 | * CPU_DYING and cleared during CPU_ONLINE, so if the worker enters | ||
1203 | * idle state or fetches works without dropping lock, it can guarantee | ||
1204 | * the scheduling requirement described in the first paragraph. | ||
1205 | * | ||
1206 | * CONTEXT: | ||
1207 | * Might sleep. Called without any lock but returns with gcwq->lock | ||
1208 | * held. | ||
1209 | * | ||
1210 | * RETURNS: | ||
1211 | * %true if the associated gcwq is online (@worker is successfully | ||
1212 | * bound), %false if offline. | ||
1213 | */ | ||
1214 | static bool worker_maybe_bind_and_lock(struct worker *worker) | ||
1215 | { | ||
1216 | struct global_cwq *gcwq = worker->gcwq; | ||
1217 | struct task_struct *task = worker->task; | ||
1218 | |||
1219 | while (true) { | ||
393 | /* | 1220 | /* |
394 | * It is permissible to free the struct work_struct | 1221 | * The following call may fail, succeed or succeed |
395 | * from inside the function that is called from it, | 1222 | * without actually migrating the task to the cpu if |
396 | * this we need to take into account for lockdep too. | 1223 | * it races with cpu hotunplug operation. Verify |
397 | * To avoid bogus "held lock freed" warnings as well | 1224 | * against GCWQ_DISASSOCIATED. |
398 | * as problems when looking into work->lockdep_map, | ||
399 | * make a copy and use that here. | ||
400 | */ | 1225 | */ |
401 | struct lockdep_map lockdep_map = work->lockdep_map; | 1226 | if (!(gcwq->flags & GCWQ_DISASSOCIATED)) |
402 | #endif | 1227 | set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); |
403 | trace_workqueue_execution(cwq->thread, work); | 1228 | |
404 | debug_work_deactivate(work); | 1229 | spin_lock_irq(&gcwq->lock); |
405 | cwq->current_work = work; | 1230 | if (gcwq->flags & GCWQ_DISASSOCIATED) |
406 | list_del_init(cwq->worklist.next); | 1231 | return false; |
407 | spin_unlock_irq(&cwq->lock); | 1232 | if (task_cpu(task) == gcwq->cpu && |
408 | 1233 | cpumask_equal(¤t->cpus_allowed, | |
409 | BUG_ON(get_wq_data(work) != cwq); | 1234 | get_cpu_mask(gcwq->cpu))) |
410 | work_clear_pending(work); | 1235 | return true; |
411 | lock_map_acquire(&cwq->wq->lockdep_map); | 1236 | spin_unlock_irq(&gcwq->lock); |
412 | lock_map_acquire(&lockdep_map); | 1237 | |
413 | f(work); | 1238 | /* CPU has come up inbetween, retry migration */ |
414 | lock_map_release(&lockdep_map); | 1239 | cpu_relax(); |
415 | lock_map_release(&cwq->wq->lockdep_map); | 1240 | } |
416 | 1241 | } | |
417 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | 1242 | |
418 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | 1243 | /* |
419 | "%s/0x%08x/%d\n", | 1244 | * Function for worker->rebind_work used to rebind rogue busy workers |
420 | current->comm, preempt_count(), | 1245 | * to the associated cpu which is coming back online. This is |
421 | task_pid_nr(current)); | 1246 | * scheduled by cpu up but can race with other cpu hotplug operations |
422 | printk(KERN_ERR " last function: "); | 1247 | * and may be executed twice without intervening cpu down. |
423 | print_symbol("%s\n", (unsigned long)f); | 1248 | */ |
424 | debug_show_held_locks(current); | 1249 | static void worker_rebind_fn(struct work_struct *work) |
425 | dump_stack(); | 1250 | { |
1251 | struct worker *worker = container_of(work, struct worker, rebind_work); | ||
1252 | struct global_cwq *gcwq = worker->gcwq; | ||
1253 | |||
1254 | if (worker_maybe_bind_and_lock(worker)) | ||
1255 | worker_clr_flags(worker, WORKER_REBIND); | ||
1256 | |||
1257 | spin_unlock_irq(&gcwq->lock); | ||
1258 | } | ||
1259 | |||
1260 | static struct worker *alloc_worker(void) | ||
1261 | { | ||
1262 | struct worker *worker; | ||
1263 | |||
1264 | worker = kzalloc(sizeof(*worker), GFP_KERNEL); | ||
1265 | if (worker) { | ||
1266 | INIT_LIST_HEAD(&worker->entry); | ||
1267 | INIT_LIST_HEAD(&worker->scheduled); | ||
1268 | INIT_WORK(&worker->rebind_work, worker_rebind_fn); | ||
1269 | /* on creation a worker is in !idle && prep state */ | ||
1270 | worker->flags = WORKER_PREP; | ||
1271 | } | ||
1272 | return worker; | ||
1273 | } | ||
1274 | |||
1275 | /** | ||
1276 | * create_worker - create a new workqueue worker | ||
1277 | * @gcwq: gcwq the new worker will belong to | ||
1278 | * @bind: whether to set affinity to @cpu or not | ||
1279 | * | ||
1280 | * Create a new worker which is bound to @gcwq. The returned worker | ||
1281 | * can be started by calling start_worker() or destroyed using | ||
1282 | * destroy_worker(). | ||
1283 | * | ||
1284 | * CONTEXT: | ||
1285 | * Might sleep. Does GFP_KERNEL allocations. | ||
1286 | * | ||
1287 | * RETURNS: | ||
1288 | * Pointer to the newly created worker. | ||
1289 | */ | ||
1290 | static struct worker *create_worker(struct global_cwq *gcwq, bool bind) | ||
1291 | { | ||
1292 | bool on_unbound_cpu = gcwq->cpu == WORK_CPU_UNBOUND; | ||
1293 | struct worker *worker = NULL; | ||
1294 | int id = -1; | ||
1295 | |||
1296 | spin_lock_irq(&gcwq->lock); | ||
1297 | while (ida_get_new(&gcwq->worker_ida, &id)) { | ||
1298 | spin_unlock_irq(&gcwq->lock); | ||
1299 | if (!ida_pre_get(&gcwq->worker_ida, GFP_KERNEL)) | ||
1300 | goto fail; | ||
1301 | spin_lock_irq(&gcwq->lock); | ||
1302 | } | ||
1303 | spin_unlock_irq(&gcwq->lock); | ||
1304 | |||
1305 | worker = alloc_worker(); | ||
1306 | if (!worker) | ||
1307 | goto fail; | ||
1308 | |||
1309 | worker->gcwq = gcwq; | ||
1310 | worker->id = id; | ||
1311 | |||
1312 | if (!on_unbound_cpu) | ||
1313 | worker->task = kthread_create(worker_thread, worker, | ||
1314 | "kworker/%u:%d", gcwq->cpu, id); | ||
1315 | else | ||
1316 | worker->task = kthread_create(worker_thread, worker, | ||
1317 | "kworker/u:%d", id); | ||
1318 | if (IS_ERR(worker->task)) | ||
1319 | goto fail; | ||
1320 | |||
1321 | /* | ||
1322 | * A rogue worker will become a regular one if CPU comes | ||
1323 | * online later on. Make sure every worker has | ||
1324 | * PF_THREAD_BOUND set. | ||
1325 | */ | ||
1326 | if (bind && !on_unbound_cpu) | ||
1327 | kthread_bind(worker->task, gcwq->cpu); | ||
1328 | else { | ||
1329 | worker->task->flags |= PF_THREAD_BOUND; | ||
1330 | if (on_unbound_cpu) | ||
1331 | worker->flags |= WORKER_UNBOUND; | ||
1332 | } | ||
1333 | |||
1334 | return worker; | ||
1335 | fail: | ||
1336 | if (id >= 0) { | ||
1337 | spin_lock_irq(&gcwq->lock); | ||
1338 | ida_remove(&gcwq->worker_ida, id); | ||
1339 | spin_unlock_irq(&gcwq->lock); | ||
1340 | } | ||
1341 | kfree(worker); | ||
1342 | return NULL; | ||
1343 | } | ||
1344 | |||
1345 | /** | ||
1346 | * start_worker - start a newly created worker | ||
1347 | * @worker: worker to start | ||
1348 | * | ||
1349 | * Make the gcwq aware of @worker and start it. | ||
1350 | * | ||
1351 | * CONTEXT: | ||
1352 | * spin_lock_irq(gcwq->lock). | ||
1353 | */ | ||
1354 | static void start_worker(struct worker *worker) | ||
1355 | { | ||
1356 | worker->flags |= WORKER_STARTED; | ||
1357 | worker->gcwq->nr_workers++; | ||
1358 | worker_enter_idle(worker); | ||
1359 | wake_up_process(worker->task); | ||
1360 | } | ||
1361 | |||
1362 | /** | ||
1363 | * destroy_worker - destroy a workqueue worker | ||
1364 | * @worker: worker to be destroyed | ||
1365 | * | ||
1366 | * Destroy @worker and adjust @gcwq stats accordingly. | ||
1367 | * | ||
1368 | * CONTEXT: | ||
1369 | * spin_lock_irq(gcwq->lock) which is released and regrabbed. | ||
1370 | */ | ||
1371 | static void destroy_worker(struct worker *worker) | ||
1372 | { | ||
1373 | struct global_cwq *gcwq = worker->gcwq; | ||
1374 | int id = worker->id; | ||
1375 | |||
1376 | /* sanity check frenzy */ | ||
1377 | BUG_ON(worker->current_work); | ||
1378 | BUG_ON(!list_empty(&worker->scheduled)); | ||
1379 | |||
1380 | if (worker->flags & WORKER_STARTED) | ||
1381 | gcwq->nr_workers--; | ||
1382 | if (worker->flags & WORKER_IDLE) | ||
1383 | gcwq->nr_idle--; | ||
1384 | |||
1385 | list_del_init(&worker->entry); | ||
1386 | worker->flags |= WORKER_DIE; | ||
1387 | |||
1388 | spin_unlock_irq(&gcwq->lock); | ||
1389 | |||
1390 | kthread_stop(worker->task); | ||
1391 | kfree(worker); | ||
1392 | |||
1393 | spin_lock_irq(&gcwq->lock); | ||
1394 | ida_remove(&gcwq->worker_ida, id); | ||
1395 | } | ||
1396 | |||
1397 | static void idle_worker_timeout(unsigned long __gcwq) | ||
1398 | { | ||
1399 | struct global_cwq *gcwq = (void *)__gcwq; | ||
1400 | |||
1401 | spin_lock_irq(&gcwq->lock); | ||
1402 | |||
1403 | if (too_many_workers(gcwq)) { | ||
1404 | struct worker *worker; | ||
1405 | unsigned long expires; | ||
1406 | |||
1407 | /* idle_list is kept in LIFO order, check the last one */ | ||
1408 | worker = list_entry(gcwq->idle_list.prev, struct worker, entry); | ||
1409 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; | ||
1410 | |||
1411 | if (time_before(jiffies, expires)) | ||
1412 | mod_timer(&gcwq->idle_timer, expires); | ||
1413 | else { | ||
1414 | /* it's been idle for too long, wake up manager */ | ||
1415 | gcwq->flags |= GCWQ_MANAGE_WORKERS; | ||
1416 | wake_up_worker(gcwq); | ||
1417 | } | ||
1418 | } | ||
1419 | |||
1420 | spin_unlock_irq(&gcwq->lock); | ||
1421 | } | ||
1422 | |||
1423 | static bool send_mayday(struct work_struct *work) | ||
1424 | { | ||
1425 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); | ||
1426 | struct workqueue_struct *wq = cwq->wq; | ||
1427 | unsigned int cpu; | ||
1428 | |||
1429 | if (!(wq->flags & WQ_RESCUER)) | ||
1430 | return false; | ||
1431 | |||
1432 | /* mayday mayday mayday */ | ||
1433 | cpu = cwq->gcwq->cpu; | ||
1434 | /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */ | ||
1435 | if (cpu == WORK_CPU_UNBOUND) | ||
1436 | cpu = 0; | ||
1437 | if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask)) | ||
1438 | wake_up_process(wq->rescuer->task); | ||
1439 | return true; | ||
1440 | } | ||
1441 | |||
1442 | static void gcwq_mayday_timeout(unsigned long __gcwq) | ||
1443 | { | ||
1444 | struct global_cwq *gcwq = (void *)__gcwq; | ||
1445 | struct work_struct *work; | ||
1446 | |||
1447 | spin_lock_irq(&gcwq->lock); | ||
1448 | |||
1449 | if (need_to_create_worker(gcwq)) { | ||
1450 | /* | ||
1451 | * We've been trying to create a new worker but | ||
1452 | * haven't been successful. We might be hitting an | ||
1453 | * allocation deadlock. Send distress signals to | ||
1454 | * rescuers. | ||
1455 | */ | ||
1456 | list_for_each_entry(work, &gcwq->worklist, entry) | ||
1457 | send_mayday(work); | ||
1458 | } | ||
1459 | |||
1460 | spin_unlock_irq(&gcwq->lock); | ||
1461 | |||
1462 | mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INTERVAL); | ||
1463 | } | ||
1464 | |||
1465 | /** | ||
1466 | * maybe_create_worker - create a new worker if necessary | ||
1467 | * @gcwq: gcwq to create a new worker for | ||
1468 | * | ||
1469 | * Create a new worker for @gcwq if necessary. @gcwq is guaranteed to | ||
1470 | * have at least one idle worker on return from this function. If | ||
1471 | * creating a new worker takes longer than MAYDAY_INTERVAL, mayday is | ||
1472 | * sent to all rescuers with works scheduled on @gcwq to resolve | ||
1473 | * possible allocation deadlock. | ||
1474 | * | ||
1475 | * On return, need_to_create_worker() is guaranteed to be false and | ||
1476 | * may_start_working() true. | ||
1477 | * | ||
1478 | * LOCKING: | ||
1479 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
1480 | * multiple times. Does GFP_KERNEL allocations. Called only from | ||
1481 | * manager. | ||
1482 | * | ||
1483 | * RETURNS: | ||
1484 | * false if no action was taken and gcwq->lock stayed locked, true | ||
1485 | * otherwise. | ||
1486 | */ | ||
1487 | static bool maybe_create_worker(struct global_cwq *gcwq) | ||
1488 | { | ||
1489 | if (!need_to_create_worker(gcwq)) | ||
1490 | return false; | ||
1491 | restart: | ||
1492 | spin_unlock_irq(&gcwq->lock); | ||
1493 | |||
1494 | /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */ | ||
1495 | mod_timer(&gcwq->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT); | ||
1496 | |||
1497 | while (true) { | ||
1498 | struct worker *worker; | ||
1499 | |||
1500 | worker = create_worker(gcwq, true); | ||
1501 | if (worker) { | ||
1502 | del_timer_sync(&gcwq->mayday_timer); | ||
1503 | spin_lock_irq(&gcwq->lock); | ||
1504 | start_worker(worker); | ||
1505 | BUG_ON(need_to_create_worker(gcwq)); | ||
1506 | return true; | ||
426 | } | 1507 | } |
427 | 1508 | ||
428 | spin_lock_irq(&cwq->lock); | 1509 | if (!need_to_create_worker(gcwq)) |
429 | cwq->current_work = NULL; | 1510 | break; |
1511 | |||
1512 | __set_current_state(TASK_INTERRUPTIBLE); | ||
1513 | schedule_timeout(CREATE_COOLDOWN); | ||
1514 | |||
1515 | if (!need_to_create_worker(gcwq)) | ||
1516 | break; | ||
430 | } | 1517 | } |
431 | spin_unlock_irq(&cwq->lock); | 1518 | |
1519 | del_timer_sync(&gcwq->mayday_timer); | ||
1520 | spin_lock_irq(&gcwq->lock); | ||
1521 | if (need_to_create_worker(gcwq)) | ||
1522 | goto restart; | ||
1523 | return true; | ||
432 | } | 1524 | } |
433 | 1525 | ||
434 | static int worker_thread(void *__cwq) | 1526 | /** |
1527 | * maybe_destroy_worker - destroy workers which have been idle for a while | ||
1528 | * @gcwq: gcwq to destroy workers for | ||
1529 | * | ||
1530 | * Destroy @gcwq workers which have been idle for longer than | ||
1531 | * IDLE_WORKER_TIMEOUT. | ||
1532 | * | ||
1533 | * LOCKING: | ||
1534 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
1535 | * multiple times. Called only from manager. | ||
1536 | * | ||
1537 | * RETURNS: | ||
1538 | * false if no action was taken and gcwq->lock stayed locked, true | ||
1539 | * otherwise. | ||
1540 | */ | ||
1541 | static bool maybe_destroy_workers(struct global_cwq *gcwq) | ||
435 | { | 1542 | { |
436 | struct cpu_workqueue_struct *cwq = __cwq; | 1543 | bool ret = false; |
437 | DEFINE_WAIT(wait); | ||
438 | 1544 | ||
439 | if (cwq->wq->freezeable) | 1545 | while (too_many_workers(gcwq)) { |
440 | set_freezable(); | 1546 | struct worker *worker; |
1547 | unsigned long expires; | ||
441 | 1548 | ||
442 | for (;;) { | 1549 | worker = list_entry(gcwq->idle_list.prev, struct worker, entry); |
443 | prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE); | 1550 | expires = worker->last_active + IDLE_WORKER_TIMEOUT; |
444 | if (!freezing(current) && | ||
445 | !kthread_should_stop() && | ||
446 | list_empty(&cwq->worklist)) | ||
447 | schedule(); | ||
448 | finish_wait(&cwq->more_work, &wait); | ||
449 | 1551 | ||
450 | try_to_freeze(); | 1552 | if (time_before(jiffies, expires)) { |
1553 | mod_timer(&gcwq->idle_timer, expires); | ||
1554 | break; | ||
1555 | } | ||
451 | 1556 | ||
452 | if (kthread_should_stop()) | 1557 | destroy_worker(worker); |
1558 | ret = true; | ||
1559 | } | ||
1560 | |||
1561 | return ret; | ||
1562 | } | ||
1563 | |||
1564 | /** | ||
1565 | * manage_workers - manage worker pool | ||
1566 | * @worker: self | ||
1567 | * | ||
1568 | * Assume the manager role and manage gcwq worker pool @worker belongs | ||
1569 | * to. At any given time, there can be only zero or one manager per | ||
1570 | * gcwq. The exclusion is handled automatically by this function. | ||
1571 | * | ||
1572 | * The caller can safely start processing works on false return. On | ||
1573 | * true return, it's guaranteed that need_to_create_worker() is false | ||
1574 | * and may_start_working() is true. | ||
1575 | * | ||
1576 | * CONTEXT: | ||
1577 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
1578 | * multiple times. Does GFP_KERNEL allocations. | ||
1579 | * | ||
1580 | * RETURNS: | ||
1581 | * false if no action was taken and gcwq->lock stayed locked, true if | ||
1582 | * some action was taken. | ||
1583 | */ | ||
1584 | static bool manage_workers(struct worker *worker) | ||
1585 | { | ||
1586 | struct global_cwq *gcwq = worker->gcwq; | ||
1587 | bool ret = false; | ||
1588 | |||
1589 | if (gcwq->flags & GCWQ_MANAGING_WORKERS) | ||
1590 | return ret; | ||
1591 | |||
1592 | gcwq->flags &= ~GCWQ_MANAGE_WORKERS; | ||
1593 | gcwq->flags |= GCWQ_MANAGING_WORKERS; | ||
1594 | |||
1595 | /* | ||
1596 | * Destroy and then create so that may_start_working() is true | ||
1597 | * on return. | ||
1598 | */ | ||
1599 | ret |= maybe_destroy_workers(gcwq); | ||
1600 | ret |= maybe_create_worker(gcwq); | ||
1601 | |||
1602 | gcwq->flags &= ~GCWQ_MANAGING_WORKERS; | ||
1603 | |||
1604 | /* | ||
1605 | * The trustee might be waiting to take over the manager | ||
1606 | * position, tell it we're done. | ||
1607 | */ | ||
1608 | if (unlikely(gcwq->trustee)) | ||
1609 | wake_up_all(&gcwq->trustee_wait); | ||
1610 | |||
1611 | return ret; | ||
1612 | } | ||
1613 | |||
1614 | /** | ||
1615 | * move_linked_works - move linked works to a list | ||
1616 | * @work: start of series of works to be scheduled | ||
1617 | * @head: target list to append @work to | ||
1618 | * @nextp: out paramter for nested worklist walking | ||
1619 | * | ||
1620 | * Schedule linked works starting from @work to @head. Work series to | ||
1621 | * be scheduled starts at @work and includes any consecutive work with | ||
1622 | * WORK_STRUCT_LINKED set in its predecessor. | ||
1623 | * | ||
1624 | * If @nextp is not NULL, it's updated to point to the next work of | ||
1625 | * the last scheduled work. This allows move_linked_works() to be | ||
1626 | * nested inside outer list_for_each_entry_safe(). | ||
1627 | * | ||
1628 | * CONTEXT: | ||
1629 | * spin_lock_irq(gcwq->lock). | ||
1630 | */ | ||
1631 | static void move_linked_works(struct work_struct *work, struct list_head *head, | ||
1632 | struct work_struct **nextp) | ||
1633 | { | ||
1634 | struct work_struct *n; | ||
1635 | |||
1636 | /* | ||
1637 | * Linked worklist will always end before the end of the list, | ||
1638 | * use NULL for list head. | ||
1639 | */ | ||
1640 | list_for_each_entry_safe_from(work, n, NULL, entry) { | ||
1641 | list_move_tail(&work->entry, head); | ||
1642 | if (!(*work_data_bits(work) & WORK_STRUCT_LINKED)) | ||
453 | break; | 1643 | break; |
1644 | } | ||
1645 | |||
1646 | /* | ||
1647 | * If we're already inside safe list traversal and have moved | ||
1648 | * multiple works to the scheduled queue, the next position | ||
1649 | * needs to be updated. | ||
1650 | */ | ||
1651 | if (nextp) | ||
1652 | *nextp = n; | ||
1653 | } | ||
1654 | |||
1655 | static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq) | ||
1656 | { | ||
1657 | struct work_struct *work = list_first_entry(&cwq->delayed_works, | ||
1658 | struct work_struct, entry); | ||
1659 | struct list_head *pos = gcwq_determine_ins_pos(cwq->gcwq, cwq); | ||
1660 | |||
1661 | move_linked_works(work, pos, NULL); | ||
1662 | cwq->nr_active++; | ||
1663 | } | ||
454 | 1664 | ||
455 | run_workqueue(cwq); | 1665 | /** |
1666 | * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight | ||
1667 | * @cwq: cwq of interest | ||
1668 | * @color: color of work which left the queue | ||
1669 | * | ||
1670 | * A work either has completed or is removed from pending queue, | ||
1671 | * decrement nr_in_flight of its cwq and handle workqueue flushing. | ||
1672 | * | ||
1673 | * CONTEXT: | ||
1674 | * spin_lock_irq(gcwq->lock). | ||
1675 | */ | ||
1676 | static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color) | ||
1677 | { | ||
1678 | /* ignore uncolored works */ | ||
1679 | if (color == WORK_NO_COLOR) | ||
1680 | return; | ||
1681 | |||
1682 | cwq->nr_in_flight[color]--; | ||
1683 | cwq->nr_active--; | ||
1684 | |||
1685 | if (!list_empty(&cwq->delayed_works)) { | ||
1686 | /* one down, submit a delayed one */ | ||
1687 | if (cwq->nr_active < cwq->max_active) | ||
1688 | cwq_activate_first_delayed(cwq); | ||
456 | } | 1689 | } |
457 | 1690 | ||
458 | return 0; | 1691 | /* is flush in progress and are we at the flushing tip? */ |
1692 | if (likely(cwq->flush_color != color)) | ||
1693 | return; | ||
1694 | |||
1695 | /* are there still in-flight works? */ | ||
1696 | if (cwq->nr_in_flight[color]) | ||
1697 | return; | ||
1698 | |||
1699 | /* this cwq is done, clear flush_color */ | ||
1700 | cwq->flush_color = -1; | ||
1701 | |||
1702 | /* | ||
1703 | * If this was the last cwq, wake up the first flusher. It | ||
1704 | * will handle the rest. | ||
1705 | */ | ||
1706 | if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush)) | ||
1707 | complete(&cwq->wq->first_flusher->done); | ||
1708 | } | ||
1709 | |||
1710 | /** | ||
1711 | * process_one_work - process single work | ||
1712 | * @worker: self | ||
1713 | * @work: work to process | ||
1714 | * | ||
1715 | * Process @work. This function contains all the logics necessary to | ||
1716 | * process a single work including synchronization against and | ||
1717 | * interaction with other workers on the same cpu, queueing and | ||
1718 | * flushing. As long as context requirement is met, any worker can | ||
1719 | * call this function to process a work. | ||
1720 | * | ||
1721 | * CONTEXT: | ||
1722 | * spin_lock_irq(gcwq->lock) which is released and regrabbed. | ||
1723 | */ | ||
1724 | static void process_one_work(struct worker *worker, struct work_struct *work) | ||
1725 | { | ||
1726 | struct cpu_workqueue_struct *cwq = get_work_cwq(work); | ||
1727 | struct global_cwq *gcwq = cwq->gcwq; | ||
1728 | struct hlist_head *bwh = busy_worker_head(gcwq, work); | ||
1729 | bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE; | ||
1730 | work_func_t f = work->func; | ||
1731 | int work_color; | ||
1732 | struct worker *collision; | ||
1733 | #ifdef CONFIG_LOCKDEP | ||
1734 | /* | ||
1735 | * It is permissible to free the struct work_struct from | ||
1736 | * inside the function that is called from it, this we need to | ||
1737 | * take into account for lockdep too. To avoid bogus "held | ||
1738 | * lock freed" warnings as well as problems when looking into | ||
1739 | * work->lockdep_map, make a copy and use that here. | ||
1740 | */ | ||
1741 | struct lockdep_map lockdep_map = work->lockdep_map; | ||
1742 | #endif | ||
1743 | /* | ||
1744 | * A single work shouldn't be executed concurrently by | ||
1745 | * multiple workers on a single cpu. Check whether anyone is | ||
1746 | * already processing the work. If so, defer the work to the | ||
1747 | * currently executing one. | ||
1748 | */ | ||
1749 | collision = __find_worker_executing_work(gcwq, bwh, work); | ||
1750 | if (unlikely(collision)) { | ||
1751 | move_linked_works(work, &collision->scheduled, NULL); | ||
1752 | return; | ||
1753 | } | ||
1754 | |||
1755 | /* claim and process */ | ||
1756 | debug_work_deactivate(work); | ||
1757 | hlist_add_head(&worker->hentry, bwh); | ||
1758 | worker->current_work = work; | ||
1759 | worker->current_cwq = cwq; | ||
1760 | work_color = get_work_color(work); | ||
1761 | |||
1762 | /* record the current cpu number in the work data and dequeue */ | ||
1763 | set_work_cpu(work, gcwq->cpu); | ||
1764 | list_del_init(&work->entry); | ||
1765 | |||
1766 | /* | ||
1767 | * If HIGHPRI_PENDING, check the next work, and, if HIGHPRI, | ||
1768 | * wake up another worker; otherwise, clear HIGHPRI_PENDING. | ||
1769 | */ | ||
1770 | if (unlikely(gcwq->flags & GCWQ_HIGHPRI_PENDING)) { | ||
1771 | struct work_struct *nwork = list_first_entry(&gcwq->worklist, | ||
1772 | struct work_struct, entry); | ||
1773 | |||
1774 | if (!list_empty(&gcwq->worklist) && | ||
1775 | get_work_cwq(nwork)->wq->flags & WQ_HIGHPRI) | ||
1776 | wake_up_worker(gcwq); | ||
1777 | else | ||
1778 | gcwq->flags &= ~GCWQ_HIGHPRI_PENDING; | ||
1779 | } | ||
1780 | |||
1781 | /* | ||
1782 | * CPU intensive works don't participate in concurrency | ||
1783 | * management. They're the scheduler's responsibility. | ||
1784 | */ | ||
1785 | if (unlikely(cpu_intensive)) | ||
1786 | worker_set_flags(worker, WORKER_CPU_INTENSIVE, true); | ||
1787 | |||
1788 | spin_unlock_irq(&gcwq->lock); | ||
1789 | |||
1790 | work_clear_pending(work); | ||
1791 | lock_map_acquire(&cwq->wq->lockdep_map); | ||
1792 | lock_map_acquire(&lockdep_map); | ||
1793 | f(work); | ||
1794 | lock_map_release(&lockdep_map); | ||
1795 | lock_map_release(&cwq->wq->lockdep_map); | ||
1796 | |||
1797 | if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { | ||
1798 | printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " | ||
1799 | "%s/0x%08x/%d\n", | ||
1800 | current->comm, preempt_count(), task_pid_nr(current)); | ||
1801 | printk(KERN_ERR " last function: "); | ||
1802 | print_symbol("%s\n", (unsigned long)f); | ||
1803 | debug_show_held_locks(current); | ||
1804 | dump_stack(); | ||
1805 | } | ||
1806 | |||
1807 | spin_lock_irq(&gcwq->lock); | ||
1808 | |||
1809 | /* clear cpu intensive status */ | ||
1810 | if (unlikely(cpu_intensive)) | ||
1811 | worker_clr_flags(worker, WORKER_CPU_INTENSIVE); | ||
1812 | |||
1813 | /* we're done with it, release */ | ||
1814 | hlist_del_init(&worker->hentry); | ||
1815 | worker->current_work = NULL; | ||
1816 | worker->current_cwq = NULL; | ||
1817 | cwq_dec_nr_in_flight(cwq, work_color); | ||
1818 | } | ||
1819 | |||
1820 | /** | ||
1821 | * process_scheduled_works - process scheduled works | ||
1822 | * @worker: self | ||
1823 | * | ||
1824 | * Process all scheduled works. Please note that the scheduled list | ||
1825 | * may change while processing a work, so this function repeatedly | ||
1826 | * fetches a work from the top and executes it. | ||
1827 | * | ||
1828 | * CONTEXT: | ||
1829 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
1830 | * multiple times. | ||
1831 | */ | ||
1832 | static void process_scheduled_works(struct worker *worker) | ||
1833 | { | ||
1834 | while (!list_empty(&worker->scheduled)) { | ||
1835 | struct work_struct *work = list_first_entry(&worker->scheduled, | ||
1836 | struct work_struct, entry); | ||
1837 | process_one_work(worker, work); | ||
1838 | } | ||
1839 | } | ||
1840 | |||
1841 | /** | ||
1842 | * worker_thread - the worker thread function | ||
1843 | * @__worker: self | ||
1844 | * | ||
1845 | * The gcwq worker thread function. There's a single dynamic pool of | ||
1846 | * these per each cpu. These workers process all works regardless of | ||
1847 | * their specific target workqueue. The only exception is works which | ||
1848 | * belong to workqueues with a rescuer which will be explained in | ||
1849 | * rescuer_thread(). | ||
1850 | */ | ||
1851 | static int worker_thread(void *__worker) | ||
1852 | { | ||
1853 | struct worker *worker = __worker; | ||
1854 | struct global_cwq *gcwq = worker->gcwq; | ||
1855 | |||
1856 | /* tell the scheduler that this is a workqueue worker */ | ||
1857 | worker->task->flags |= PF_WQ_WORKER; | ||
1858 | woke_up: | ||
1859 | spin_lock_irq(&gcwq->lock); | ||
1860 | |||
1861 | /* DIE can be set only while we're idle, checking here is enough */ | ||
1862 | if (worker->flags & WORKER_DIE) { | ||
1863 | spin_unlock_irq(&gcwq->lock); | ||
1864 | worker->task->flags &= ~PF_WQ_WORKER; | ||
1865 | return 0; | ||
1866 | } | ||
1867 | |||
1868 | worker_leave_idle(worker); | ||
1869 | recheck: | ||
1870 | /* no more worker necessary? */ | ||
1871 | if (!need_more_worker(gcwq)) | ||
1872 | goto sleep; | ||
1873 | |||
1874 | /* do we need to manage? */ | ||
1875 | if (unlikely(!may_start_working(gcwq)) && manage_workers(worker)) | ||
1876 | goto recheck; | ||
1877 | |||
1878 | /* | ||
1879 | * ->scheduled list can only be filled while a worker is | ||
1880 | * preparing to process a work or actually processing it. | ||
1881 | * Make sure nobody diddled with it while I was sleeping. | ||
1882 | */ | ||
1883 | BUG_ON(!list_empty(&worker->scheduled)); | ||
1884 | |||
1885 | /* | ||
1886 | * When control reaches this point, we're guaranteed to have | ||
1887 | * at least one idle worker or that someone else has already | ||
1888 | * assumed the manager role. | ||
1889 | */ | ||
1890 | worker_clr_flags(worker, WORKER_PREP); | ||
1891 | |||
1892 | do { | ||
1893 | struct work_struct *work = | ||
1894 | list_first_entry(&gcwq->worklist, | ||
1895 | struct work_struct, entry); | ||
1896 | |||
1897 | if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) { | ||
1898 | /* optimization path, not strictly necessary */ | ||
1899 | process_one_work(worker, work); | ||
1900 | if (unlikely(!list_empty(&worker->scheduled))) | ||
1901 | process_scheduled_works(worker); | ||
1902 | } else { | ||
1903 | move_linked_works(work, &worker->scheduled, NULL); | ||
1904 | process_scheduled_works(worker); | ||
1905 | } | ||
1906 | } while (keep_working(gcwq)); | ||
1907 | |||
1908 | worker_set_flags(worker, WORKER_PREP, false); | ||
1909 | sleep: | ||
1910 | if (unlikely(need_to_manage_workers(gcwq)) && manage_workers(worker)) | ||
1911 | goto recheck; | ||
1912 | |||
1913 | /* | ||
1914 | * gcwq->lock is held and there's no work to process and no | ||
1915 | * need to manage, sleep. Workers are woken up only while | ||
1916 | * holding gcwq->lock or from local cpu, so setting the | ||
1917 | * current state before releasing gcwq->lock is enough to | ||
1918 | * prevent losing any event. | ||
1919 | */ | ||
1920 | worker_enter_idle(worker); | ||
1921 | __set_current_state(TASK_INTERRUPTIBLE); | ||
1922 | spin_unlock_irq(&gcwq->lock); | ||
1923 | schedule(); | ||
1924 | goto woke_up; | ||
1925 | } | ||
1926 | |||
1927 | /** | ||
1928 | * rescuer_thread - the rescuer thread function | ||
1929 | * @__wq: the associated workqueue | ||
1930 | * | ||
1931 | * Workqueue rescuer thread function. There's one rescuer for each | ||
1932 | * workqueue which has WQ_RESCUER set. | ||
1933 | * | ||
1934 | * Regular work processing on a gcwq may block trying to create a new | ||
1935 | * worker which uses GFP_KERNEL allocation which has slight chance of | ||
1936 | * developing into deadlock if some works currently on the same queue | ||
1937 | * need to be processed to satisfy the GFP_KERNEL allocation. This is | ||
1938 | * the problem rescuer solves. | ||
1939 | * | ||
1940 | * When such condition is possible, the gcwq summons rescuers of all | ||
1941 | * workqueues which have works queued on the gcwq and let them process | ||
1942 | * those works so that forward progress can be guaranteed. | ||
1943 | * | ||
1944 | * This should happen rarely. | ||
1945 | */ | ||
1946 | static int rescuer_thread(void *__wq) | ||
1947 | { | ||
1948 | struct workqueue_struct *wq = __wq; | ||
1949 | struct worker *rescuer = wq->rescuer; | ||
1950 | struct list_head *scheduled = &rescuer->scheduled; | ||
1951 | bool is_unbound = wq->flags & WQ_UNBOUND; | ||
1952 | unsigned int cpu; | ||
1953 | |||
1954 | set_user_nice(current, RESCUER_NICE_LEVEL); | ||
1955 | repeat: | ||
1956 | set_current_state(TASK_INTERRUPTIBLE); | ||
1957 | |||
1958 | if (kthread_should_stop()) | ||
1959 | return 0; | ||
1960 | |||
1961 | /* | ||
1962 | * See whether any cpu is asking for help. Unbounded | ||
1963 | * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND. | ||
1964 | */ | ||
1965 | for_each_mayday_cpu(cpu, wq->mayday_mask) { | ||
1966 | unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu; | ||
1967 | struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq); | ||
1968 | struct global_cwq *gcwq = cwq->gcwq; | ||
1969 | struct work_struct *work, *n; | ||
1970 | |||
1971 | __set_current_state(TASK_RUNNING); | ||
1972 | mayday_clear_cpu(cpu, wq->mayday_mask); | ||
1973 | |||
1974 | /* migrate to the target cpu if possible */ | ||
1975 | rescuer->gcwq = gcwq; | ||
1976 | worker_maybe_bind_and_lock(rescuer); | ||
1977 | |||
1978 | /* | ||
1979 | * Slurp in all works issued via this workqueue and | ||
1980 | * process'em. | ||
1981 | */ | ||
1982 | BUG_ON(!list_empty(&rescuer->scheduled)); | ||
1983 | list_for_each_entry_safe(work, n, &gcwq->worklist, entry) | ||
1984 | if (get_work_cwq(work) == cwq) | ||
1985 | move_linked_works(work, scheduled, &n); | ||
1986 | |||
1987 | process_scheduled_works(rescuer); | ||
1988 | spin_unlock_irq(&gcwq->lock); | ||
1989 | } | ||
1990 | |||
1991 | schedule(); | ||
1992 | goto repeat; | ||
459 | } | 1993 | } |
460 | 1994 | ||
461 | struct wq_barrier { | 1995 | struct wq_barrier { |
@@ -469,44 +2003,137 @@ static void wq_barrier_func(struct work_struct *work) | |||
469 | complete(&barr->done); | 2003 | complete(&barr->done); |
470 | } | 2004 | } |
471 | 2005 | ||
2006 | /** | ||
2007 | * insert_wq_barrier - insert a barrier work | ||
2008 | * @cwq: cwq to insert barrier into | ||
2009 | * @barr: wq_barrier to insert | ||
2010 | * @target: target work to attach @barr to | ||
2011 | * @worker: worker currently executing @target, NULL if @target is not executing | ||
2012 | * | ||
2013 | * @barr is linked to @target such that @barr is completed only after | ||
2014 | * @target finishes execution. Please note that the ordering | ||
2015 | * guarantee is observed only with respect to @target and on the local | ||
2016 | * cpu. | ||
2017 | * | ||
2018 | * Currently, a queued barrier can't be canceled. This is because | ||
2019 | * try_to_grab_pending() can't determine whether the work to be | ||
2020 | * grabbed is at the head of the queue and thus can't clear LINKED | ||
2021 | * flag of the previous work while there must be a valid next work | ||
2022 | * after a work with LINKED flag set. | ||
2023 | * | ||
2024 | * Note that when @worker is non-NULL, @target may be modified | ||
2025 | * underneath us, so we can't reliably determine cwq from @target. | ||
2026 | * | ||
2027 | * CONTEXT: | ||
2028 | * spin_lock_irq(gcwq->lock). | ||
2029 | */ | ||
472 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, | 2030 | static void insert_wq_barrier(struct cpu_workqueue_struct *cwq, |
473 | struct wq_barrier *barr, struct list_head *head) | 2031 | struct wq_barrier *barr, |
2032 | struct work_struct *target, struct worker *worker) | ||
474 | { | 2033 | { |
2034 | struct list_head *head; | ||
2035 | unsigned int linked = 0; | ||
2036 | |||
475 | /* | 2037 | /* |
476 | * debugobject calls are safe here even with cwq->lock locked | 2038 | * debugobject calls are safe here even with gcwq->lock locked |
477 | * as we know for sure that this will not trigger any of the | 2039 | * as we know for sure that this will not trigger any of the |
478 | * checks and call back into the fixup functions where we | 2040 | * checks and call back into the fixup functions where we |
479 | * might deadlock. | 2041 | * might deadlock. |
480 | */ | 2042 | */ |
481 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); | 2043 | INIT_WORK_ON_STACK(&barr->work, wq_barrier_func); |
482 | __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); | 2044 | __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); |
483 | |||
484 | init_completion(&barr->done); | 2045 | init_completion(&barr->done); |
485 | 2046 | ||
2047 | /* | ||
2048 | * If @target is currently being executed, schedule the | ||
2049 | * barrier to the worker; otherwise, put it after @target. | ||
2050 | */ | ||
2051 | if (worker) | ||
2052 | head = worker->scheduled.next; | ||
2053 | else { | ||
2054 | unsigned long *bits = work_data_bits(target); | ||
2055 | |||
2056 | head = target->entry.next; | ||
2057 | /* there can already be other linked works, inherit and set */ | ||
2058 | linked = *bits & WORK_STRUCT_LINKED; | ||
2059 | __set_bit(WORK_STRUCT_LINKED_BIT, bits); | ||
2060 | } | ||
2061 | |||
486 | debug_work_activate(&barr->work); | 2062 | debug_work_activate(&barr->work); |
487 | insert_work(cwq, &barr->work, head); | 2063 | insert_work(cwq, &barr->work, head, |
2064 | work_color_to_flags(WORK_NO_COLOR) | linked); | ||
488 | } | 2065 | } |
489 | 2066 | ||
490 | static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | 2067 | /** |
2068 | * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing | ||
2069 | * @wq: workqueue being flushed | ||
2070 | * @flush_color: new flush color, < 0 for no-op | ||
2071 | * @work_color: new work color, < 0 for no-op | ||
2072 | * | ||
2073 | * Prepare cwqs for workqueue flushing. | ||
2074 | * | ||
2075 | * If @flush_color is non-negative, flush_color on all cwqs should be | ||
2076 | * -1. If no cwq has in-flight commands at the specified color, all | ||
2077 | * cwq->flush_color's stay at -1 and %false is returned. If any cwq | ||
2078 | * has in flight commands, its cwq->flush_color is set to | ||
2079 | * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq | ||
2080 | * wakeup logic is armed and %true is returned. | ||
2081 | * | ||
2082 | * The caller should have initialized @wq->first_flusher prior to | ||
2083 | * calling this function with non-negative @flush_color. If | ||
2084 | * @flush_color is negative, no flush color update is done and %false | ||
2085 | * is returned. | ||
2086 | * | ||
2087 | * If @work_color is non-negative, all cwqs should have the same | ||
2088 | * work_color which is previous to @work_color and all will be | ||
2089 | * advanced to @work_color. | ||
2090 | * | ||
2091 | * CONTEXT: | ||
2092 | * mutex_lock(wq->flush_mutex). | ||
2093 | * | ||
2094 | * RETURNS: | ||
2095 | * %true if @flush_color >= 0 and there's something to flush. %false | ||
2096 | * otherwise. | ||
2097 | */ | ||
2098 | static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq, | ||
2099 | int flush_color, int work_color) | ||
491 | { | 2100 | { |
492 | int active = 0; | 2101 | bool wait = false; |
493 | struct wq_barrier barr; | 2102 | unsigned int cpu; |
494 | 2103 | ||
495 | WARN_ON(cwq->thread == current); | 2104 | if (flush_color >= 0) { |
496 | 2105 | BUG_ON(atomic_read(&wq->nr_cwqs_to_flush)); | |
497 | spin_lock_irq(&cwq->lock); | 2106 | atomic_set(&wq->nr_cwqs_to_flush, 1); |
498 | if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) { | ||
499 | insert_wq_barrier(cwq, &barr, &cwq->worklist); | ||
500 | active = 1; | ||
501 | } | 2107 | } |
502 | spin_unlock_irq(&cwq->lock); | ||
503 | 2108 | ||
504 | if (active) { | 2109 | for_each_cwq_cpu(cpu, wq) { |
505 | wait_for_completion(&barr.done); | 2110 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
506 | destroy_work_on_stack(&barr.work); | 2111 | struct global_cwq *gcwq = cwq->gcwq; |
2112 | |||
2113 | spin_lock_irq(&gcwq->lock); | ||
2114 | |||
2115 | if (flush_color >= 0) { | ||
2116 | BUG_ON(cwq->flush_color != -1); | ||
2117 | |||
2118 | if (cwq->nr_in_flight[flush_color]) { | ||
2119 | cwq->flush_color = flush_color; | ||
2120 | atomic_inc(&wq->nr_cwqs_to_flush); | ||
2121 | wait = true; | ||
2122 | } | ||
2123 | } | ||
2124 | |||
2125 | if (work_color >= 0) { | ||
2126 | BUG_ON(work_color != work_next_color(cwq->work_color)); | ||
2127 | cwq->work_color = work_color; | ||
2128 | } | ||
2129 | |||
2130 | spin_unlock_irq(&gcwq->lock); | ||
507 | } | 2131 | } |
508 | 2132 | ||
509 | return active; | 2133 | if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush)) |
2134 | complete(&wq->first_flusher->done); | ||
2135 | |||
2136 | return wait; | ||
510 | } | 2137 | } |
511 | 2138 | ||
512 | /** | 2139 | /** |
@@ -518,20 +2145,150 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) | |||
518 | * | 2145 | * |
519 | * We sleep until all works which were queued on entry have been handled, | 2146 | * We sleep until all works which were queued on entry have been handled, |
520 | * but we are not livelocked by new incoming ones. | 2147 | * but we are not livelocked by new incoming ones. |
521 | * | ||
522 | * This function used to run the workqueues itself. Now we just wait for the | ||
523 | * helper threads to do it. | ||
524 | */ | 2148 | */ |
525 | void flush_workqueue(struct workqueue_struct *wq) | 2149 | void flush_workqueue(struct workqueue_struct *wq) |
526 | { | 2150 | { |
527 | const struct cpumask *cpu_map = wq_cpu_map(wq); | 2151 | struct wq_flusher this_flusher = { |
528 | int cpu; | 2152 | .list = LIST_HEAD_INIT(this_flusher.list), |
2153 | .flush_color = -1, | ||
2154 | .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done), | ||
2155 | }; | ||
2156 | int next_color; | ||
529 | 2157 | ||
530 | might_sleep(); | ||
531 | lock_map_acquire(&wq->lockdep_map); | 2158 | lock_map_acquire(&wq->lockdep_map); |
532 | lock_map_release(&wq->lockdep_map); | 2159 | lock_map_release(&wq->lockdep_map); |
533 | for_each_cpu(cpu, cpu_map) | 2160 | |
534 | flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); | 2161 | mutex_lock(&wq->flush_mutex); |
2162 | |||
2163 | /* | ||
2164 | * Start-to-wait phase | ||
2165 | */ | ||
2166 | next_color = work_next_color(wq->work_color); | ||
2167 | |||
2168 | if (next_color != wq->flush_color) { | ||
2169 | /* | ||
2170 | * Color space is not full. The current work_color | ||
2171 | * becomes our flush_color and work_color is advanced | ||
2172 | * by one. | ||
2173 | */ | ||
2174 | BUG_ON(!list_empty(&wq->flusher_overflow)); | ||
2175 | this_flusher.flush_color = wq->work_color; | ||
2176 | wq->work_color = next_color; | ||
2177 | |||
2178 | if (!wq->first_flusher) { | ||
2179 | /* no flush in progress, become the first flusher */ | ||
2180 | BUG_ON(wq->flush_color != this_flusher.flush_color); | ||
2181 | |||
2182 | wq->first_flusher = &this_flusher; | ||
2183 | |||
2184 | if (!flush_workqueue_prep_cwqs(wq, wq->flush_color, | ||
2185 | wq->work_color)) { | ||
2186 | /* nothing to flush, done */ | ||
2187 | wq->flush_color = next_color; | ||
2188 | wq->first_flusher = NULL; | ||
2189 | goto out_unlock; | ||
2190 | } | ||
2191 | } else { | ||
2192 | /* wait in queue */ | ||
2193 | BUG_ON(wq->flush_color == this_flusher.flush_color); | ||
2194 | list_add_tail(&this_flusher.list, &wq->flusher_queue); | ||
2195 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | ||
2196 | } | ||
2197 | } else { | ||
2198 | /* | ||
2199 | * Oops, color space is full, wait on overflow queue. | ||
2200 | * The next flush completion will assign us | ||
2201 | * flush_color and transfer to flusher_queue. | ||
2202 | */ | ||
2203 | list_add_tail(&this_flusher.list, &wq->flusher_overflow); | ||
2204 | } | ||
2205 | |||
2206 | mutex_unlock(&wq->flush_mutex); | ||
2207 | |||
2208 | wait_for_completion(&this_flusher.done); | ||
2209 | |||
2210 | /* | ||
2211 | * Wake-up-and-cascade phase | ||
2212 | * | ||
2213 | * First flushers are responsible for cascading flushes and | ||
2214 | * handling overflow. Non-first flushers can simply return. | ||
2215 | */ | ||
2216 | if (wq->first_flusher != &this_flusher) | ||
2217 | return; | ||
2218 | |||
2219 | mutex_lock(&wq->flush_mutex); | ||
2220 | |||
2221 | /* we might have raced, check again with mutex held */ | ||
2222 | if (wq->first_flusher != &this_flusher) | ||
2223 | goto out_unlock; | ||
2224 | |||
2225 | wq->first_flusher = NULL; | ||
2226 | |||
2227 | BUG_ON(!list_empty(&this_flusher.list)); | ||
2228 | BUG_ON(wq->flush_color != this_flusher.flush_color); | ||
2229 | |||
2230 | while (true) { | ||
2231 | struct wq_flusher *next, *tmp; | ||
2232 | |||
2233 | /* complete all the flushers sharing the current flush color */ | ||
2234 | list_for_each_entry_safe(next, tmp, &wq->flusher_queue, list) { | ||
2235 | if (next->flush_color != wq->flush_color) | ||
2236 | break; | ||
2237 | list_del_init(&next->list); | ||
2238 | complete(&next->done); | ||
2239 | } | ||
2240 | |||
2241 | BUG_ON(!list_empty(&wq->flusher_overflow) && | ||
2242 | wq->flush_color != work_next_color(wq->work_color)); | ||
2243 | |||
2244 | /* this flush_color is finished, advance by one */ | ||
2245 | wq->flush_color = work_next_color(wq->flush_color); | ||
2246 | |||
2247 | /* one color has been freed, handle overflow queue */ | ||
2248 | if (!list_empty(&wq->flusher_overflow)) { | ||
2249 | /* | ||
2250 | * Assign the same color to all overflowed | ||
2251 | * flushers, advance work_color and append to | ||
2252 | * flusher_queue. This is the start-to-wait | ||
2253 | * phase for these overflowed flushers. | ||
2254 | */ | ||
2255 | list_for_each_entry(tmp, &wq->flusher_overflow, list) | ||
2256 | tmp->flush_color = wq->work_color; | ||
2257 | |||
2258 | wq->work_color = work_next_color(wq->work_color); | ||
2259 | |||
2260 | list_splice_tail_init(&wq->flusher_overflow, | ||
2261 | &wq->flusher_queue); | ||
2262 | flush_workqueue_prep_cwqs(wq, -1, wq->work_color); | ||
2263 | } | ||
2264 | |||
2265 | if (list_empty(&wq->flusher_queue)) { | ||
2266 | BUG_ON(wq->flush_color != wq->work_color); | ||
2267 | break; | ||
2268 | } | ||
2269 | |||
2270 | /* | ||
2271 | * Need to flush more colors. Make the next flusher | ||
2272 | * the new first flusher and arm cwqs. | ||
2273 | */ | ||
2274 | BUG_ON(wq->flush_color == wq->work_color); | ||
2275 | BUG_ON(wq->flush_color != next->flush_color); | ||
2276 | |||
2277 | list_del_init(&next->list); | ||
2278 | wq->first_flusher = next; | ||
2279 | |||
2280 | if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1)) | ||
2281 | break; | ||
2282 | |||
2283 | /* | ||
2284 | * Meh... this color is already done, clear first | ||
2285 | * flusher and repeat cascading. | ||
2286 | */ | ||
2287 | wq->first_flusher = NULL; | ||
2288 | } | ||
2289 | |||
2290 | out_unlock: | ||
2291 | mutex_unlock(&wq->flush_mutex); | ||
535 | } | 2292 | } |
536 | EXPORT_SYMBOL_GPL(flush_workqueue); | 2293 | EXPORT_SYMBOL_GPL(flush_workqueue); |
537 | 2294 | ||
@@ -547,43 +2304,46 @@ EXPORT_SYMBOL_GPL(flush_workqueue); | |||
547 | */ | 2304 | */ |
548 | int flush_work(struct work_struct *work) | 2305 | int flush_work(struct work_struct *work) |
549 | { | 2306 | { |
2307 | struct worker *worker = NULL; | ||
2308 | struct global_cwq *gcwq; | ||
550 | struct cpu_workqueue_struct *cwq; | 2309 | struct cpu_workqueue_struct *cwq; |
551 | struct list_head *prev; | ||
552 | struct wq_barrier barr; | 2310 | struct wq_barrier barr; |
553 | 2311 | ||
554 | might_sleep(); | 2312 | might_sleep(); |
555 | cwq = get_wq_data(work); | 2313 | gcwq = get_work_gcwq(work); |
556 | if (!cwq) | 2314 | if (!gcwq) |
557 | return 0; | 2315 | return 0; |
558 | 2316 | ||
559 | lock_map_acquire(&cwq->wq->lockdep_map); | 2317 | spin_lock_irq(&gcwq->lock); |
560 | lock_map_release(&cwq->wq->lockdep_map); | ||
561 | |||
562 | prev = NULL; | ||
563 | spin_lock_irq(&cwq->lock); | ||
564 | if (!list_empty(&work->entry)) { | 2318 | if (!list_empty(&work->entry)) { |
565 | /* | 2319 | /* |
566 | * See the comment near try_to_grab_pending()->smp_rmb(). | 2320 | * See the comment near try_to_grab_pending()->smp_rmb(). |
567 | * If it was re-queued under us we are not going to wait. | 2321 | * If it was re-queued to a different gcwq under us, we |
2322 | * are not going to wait. | ||
568 | */ | 2323 | */ |
569 | smp_rmb(); | 2324 | smp_rmb(); |
570 | if (unlikely(cwq != get_wq_data(work))) | 2325 | cwq = get_work_cwq(work); |
571 | goto out; | 2326 | if (unlikely(!cwq || gcwq != cwq->gcwq)) |
572 | prev = &work->entry; | 2327 | goto already_gone; |
573 | } else { | 2328 | } else { |
574 | if (cwq->current_work != work) | 2329 | worker = find_worker_executing_work(gcwq, work); |
575 | goto out; | 2330 | if (!worker) |
576 | prev = &cwq->worklist; | 2331 | goto already_gone; |
2332 | cwq = worker->current_cwq; | ||
577 | } | 2333 | } |
578 | insert_wq_barrier(cwq, &barr, prev->next); | 2334 | |
579 | out: | 2335 | insert_wq_barrier(cwq, &barr, work, worker); |
580 | spin_unlock_irq(&cwq->lock); | 2336 | spin_unlock_irq(&gcwq->lock); |
581 | if (!prev) | 2337 | |
582 | return 0; | 2338 | lock_map_acquire(&cwq->wq->lockdep_map); |
2339 | lock_map_release(&cwq->wq->lockdep_map); | ||
583 | 2340 | ||
584 | wait_for_completion(&barr.done); | 2341 | wait_for_completion(&barr.done); |
585 | destroy_work_on_stack(&barr.work); | 2342 | destroy_work_on_stack(&barr.work); |
586 | return 1; | 2343 | return 1; |
2344 | already_gone: | ||
2345 | spin_unlock_irq(&gcwq->lock); | ||
2346 | return 0; | ||
587 | } | 2347 | } |
588 | EXPORT_SYMBOL_GPL(flush_work); | 2348 | EXPORT_SYMBOL_GPL(flush_work); |
589 | 2349 | ||
@@ -593,54 +2353,55 @@ EXPORT_SYMBOL_GPL(flush_work); | |||
593 | */ | 2353 | */ |
594 | static int try_to_grab_pending(struct work_struct *work) | 2354 | static int try_to_grab_pending(struct work_struct *work) |
595 | { | 2355 | { |
596 | struct cpu_workqueue_struct *cwq; | 2356 | struct global_cwq *gcwq; |
597 | int ret = -1; | 2357 | int ret = -1; |
598 | 2358 | ||
599 | if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) | 2359 | if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) |
600 | return 0; | 2360 | return 0; |
601 | 2361 | ||
602 | /* | 2362 | /* |
603 | * The queueing is in progress, or it is already queued. Try to | 2363 | * The queueing is in progress, or it is already queued. Try to |
604 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. | 2364 | * steal it from ->worklist without clearing WORK_STRUCT_PENDING. |
605 | */ | 2365 | */ |
606 | 2366 | gcwq = get_work_gcwq(work); | |
607 | cwq = get_wq_data(work); | 2367 | if (!gcwq) |
608 | if (!cwq) | ||
609 | return ret; | 2368 | return ret; |
610 | 2369 | ||
611 | spin_lock_irq(&cwq->lock); | 2370 | spin_lock_irq(&gcwq->lock); |
612 | if (!list_empty(&work->entry)) { | 2371 | if (!list_empty(&work->entry)) { |
613 | /* | 2372 | /* |
614 | * This work is queued, but perhaps we locked the wrong cwq. | 2373 | * This work is queued, but perhaps we locked the wrong gcwq. |
615 | * In that case we must see the new value after rmb(), see | 2374 | * In that case we must see the new value after rmb(), see |
616 | * insert_work()->wmb(). | 2375 | * insert_work()->wmb(). |
617 | */ | 2376 | */ |
618 | smp_rmb(); | 2377 | smp_rmb(); |
619 | if (cwq == get_wq_data(work)) { | 2378 | if (gcwq == get_work_gcwq(work)) { |
620 | debug_work_deactivate(work); | 2379 | debug_work_deactivate(work); |
621 | list_del_init(&work->entry); | 2380 | list_del_init(&work->entry); |
2381 | cwq_dec_nr_in_flight(get_work_cwq(work), | ||
2382 | get_work_color(work)); | ||
622 | ret = 1; | 2383 | ret = 1; |
623 | } | 2384 | } |
624 | } | 2385 | } |
625 | spin_unlock_irq(&cwq->lock); | 2386 | spin_unlock_irq(&gcwq->lock); |
626 | 2387 | ||
627 | return ret; | 2388 | return ret; |
628 | } | 2389 | } |
629 | 2390 | ||
630 | static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | 2391 | static void wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) |
631 | struct work_struct *work) | ||
632 | { | 2392 | { |
633 | struct wq_barrier barr; | 2393 | struct wq_barrier barr; |
634 | int running = 0; | 2394 | struct worker *worker; |
635 | 2395 | ||
636 | spin_lock_irq(&cwq->lock); | 2396 | spin_lock_irq(&gcwq->lock); |
637 | if (unlikely(cwq->current_work == work)) { | 2397 | |
638 | insert_wq_barrier(cwq, &barr, cwq->worklist.next); | 2398 | worker = find_worker_executing_work(gcwq, work); |
639 | running = 1; | 2399 | if (unlikely(worker)) |
640 | } | 2400 | insert_wq_barrier(worker->current_cwq, &barr, work, worker); |
641 | spin_unlock_irq(&cwq->lock); | ||
642 | 2401 | ||
643 | if (unlikely(running)) { | 2402 | spin_unlock_irq(&gcwq->lock); |
2403 | |||
2404 | if (unlikely(worker)) { | ||
644 | wait_for_completion(&barr.done); | 2405 | wait_for_completion(&barr.done); |
645 | destroy_work_on_stack(&barr.work); | 2406 | destroy_work_on_stack(&barr.work); |
646 | } | 2407 | } |
@@ -648,9 +2409,6 @@ static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq, | |||
648 | 2409 | ||
649 | static void wait_on_work(struct work_struct *work) | 2410 | static void wait_on_work(struct work_struct *work) |
650 | { | 2411 | { |
651 | struct cpu_workqueue_struct *cwq; | ||
652 | struct workqueue_struct *wq; | ||
653 | const struct cpumask *cpu_map; | ||
654 | int cpu; | 2412 | int cpu; |
655 | 2413 | ||
656 | might_sleep(); | 2414 | might_sleep(); |
@@ -658,15 +2416,8 @@ static void wait_on_work(struct work_struct *work) | |||
658 | lock_map_acquire(&work->lockdep_map); | 2416 | lock_map_acquire(&work->lockdep_map); |
659 | lock_map_release(&work->lockdep_map); | 2417 | lock_map_release(&work->lockdep_map); |
660 | 2418 | ||
661 | cwq = get_wq_data(work); | 2419 | for_each_gcwq_cpu(cpu) |
662 | if (!cwq) | 2420 | wait_on_cpu_work(get_gcwq(cpu), work); |
663 | return; | ||
664 | |||
665 | wq = cwq->wq; | ||
666 | cpu_map = wq_cpu_map(wq); | ||
667 | |||
668 | for_each_cpu(cpu, cpu_map) | ||
669 | wait_on_cpu_work(per_cpu_ptr(wq->cpu_wq, cpu), work); | ||
670 | } | 2421 | } |
671 | 2422 | ||
672 | static int __cancel_work_timer(struct work_struct *work, | 2423 | static int __cancel_work_timer(struct work_struct *work, |
@@ -681,7 +2432,7 @@ static int __cancel_work_timer(struct work_struct *work, | |||
681 | wait_on_work(work); | 2432 | wait_on_work(work); |
682 | } while (unlikely(ret < 0)); | 2433 | } while (unlikely(ret < 0)); |
683 | 2434 | ||
684 | clear_wq_data(work); | 2435 | clear_work_data(work); |
685 | return ret; | 2436 | return ret; |
686 | } | 2437 | } |
687 | 2438 | ||
@@ -727,8 +2478,6 @@ int cancel_delayed_work_sync(struct delayed_work *dwork) | |||
727 | } | 2478 | } |
728 | EXPORT_SYMBOL(cancel_delayed_work_sync); | 2479 | EXPORT_SYMBOL(cancel_delayed_work_sync); |
729 | 2480 | ||
730 | static struct workqueue_struct *keventd_wq __read_mostly; | ||
731 | |||
732 | /** | 2481 | /** |
733 | * schedule_work - put work task in global workqueue | 2482 | * schedule_work - put work task in global workqueue |
734 | * @work: job to be done | 2483 | * @work: job to be done |
@@ -742,7 +2491,7 @@ static struct workqueue_struct *keventd_wq __read_mostly; | |||
742 | */ | 2491 | */ |
743 | int schedule_work(struct work_struct *work) | 2492 | int schedule_work(struct work_struct *work) |
744 | { | 2493 | { |
745 | return queue_work(keventd_wq, work); | 2494 | return queue_work(system_wq, work); |
746 | } | 2495 | } |
747 | EXPORT_SYMBOL(schedule_work); | 2496 | EXPORT_SYMBOL(schedule_work); |
748 | 2497 | ||
@@ -755,7 +2504,7 @@ EXPORT_SYMBOL(schedule_work); | |||
755 | */ | 2504 | */ |
756 | int schedule_work_on(int cpu, struct work_struct *work) | 2505 | int schedule_work_on(int cpu, struct work_struct *work) |
757 | { | 2506 | { |
758 | return queue_work_on(cpu, keventd_wq, work); | 2507 | return queue_work_on(cpu, system_wq, work); |
759 | } | 2508 | } |
760 | EXPORT_SYMBOL(schedule_work_on); | 2509 | EXPORT_SYMBOL(schedule_work_on); |
761 | 2510 | ||
@@ -770,7 +2519,7 @@ EXPORT_SYMBOL(schedule_work_on); | |||
770 | int schedule_delayed_work(struct delayed_work *dwork, | 2519 | int schedule_delayed_work(struct delayed_work *dwork, |
771 | unsigned long delay) | 2520 | unsigned long delay) |
772 | { | 2521 | { |
773 | return queue_delayed_work(keventd_wq, dwork, delay); | 2522 | return queue_delayed_work(system_wq, dwork, delay); |
774 | } | 2523 | } |
775 | EXPORT_SYMBOL(schedule_delayed_work); | 2524 | EXPORT_SYMBOL(schedule_delayed_work); |
776 | 2525 | ||
@@ -783,9 +2532,8 @@ EXPORT_SYMBOL(schedule_delayed_work); | |||
783 | void flush_delayed_work(struct delayed_work *dwork) | 2532 | void flush_delayed_work(struct delayed_work *dwork) |
784 | { | 2533 | { |
785 | if (del_timer_sync(&dwork->timer)) { | 2534 | if (del_timer_sync(&dwork->timer)) { |
786 | struct cpu_workqueue_struct *cwq; | 2535 | __queue_work(get_cpu(), get_work_cwq(&dwork->work)->wq, |
787 | cwq = wq_per_cpu(get_wq_data(&dwork->work)->wq, get_cpu()); | 2536 | &dwork->work); |
788 | __queue_work(cwq, &dwork->work); | ||
789 | put_cpu(); | 2537 | put_cpu(); |
790 | } | 2538 | } |
791 | flush_work(&dwork->work); | 2539 | flush_work(&dwork->work); |
@@ -804,7 +2552,7 @@ EXPORT_SYMBOL(flush_delayed_work); | |||
804 | int schedule_delayed_work_on(int cpu, | 2552 | int schedule_delayed_work_on(int cpu, |
805 | struct delayed_work *dwork, unsigned long delay) | 2553 | struct delayed_work *dwork, unsigned long delay) |
806 | { | 2554 | { |
807 | return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); | 2555 | return queue_delayed_work_on(cpu, system_wq, dwork, delay); |
808 | } | 2556 | } |
809 | EXPORT_SYMBOL(schedule_delayed_work_on); | 2557 | EXPORT_SYMBOL(schedule_delayed_work_on); |
810 | 2558 | ||
@@ -820,8 +2568,7 @@ EXPORT_SYMBOL(schedule_delayed_work_on); | |||
820 | int schedule_on_each_cpu(work_func_t func) | 2568 | int schedule_on_each_cpu(work_func_t func) |
821 | { | 2569 | { |
822 | int cpu; | 2570 | int cpu; |
823 | int orig = -1; | 2571 | struct work_struct __percpu *works; |
824 | struct work_struct *works; | ||
825 | 2572 | ||
826 | works = alloc_percpu(struct work_struct); | 2573 | works = alloc_percpu(struct work_struct); |
827 | if (!works) | 2574 | if (!works) |
@@ -829,23 +2576,12 @@ int schedule_on_each_cpu(work_func_t func) | |||
829 | 2576 | ||
830 | get_online_cpus(); | 2577 | get_online_cpus(); |
831 | 2578 | ||
832 | /* | ||
833 | * When running in keventd don't schedule a work item on | ||
834 | * itself. Can just call directly because the work queue is | ||
835 | * already bound. This also is faster. | ||
836 | */ | ||
837 | if (current_is_keventd()) | ||
838 | orig = raw_smp_processor_id(); | ||
839 | |||
840 | for_each_online_cpu(cpu) { | 2579 | for_each_online_cpu(cpu) { |
841 | struct work_struct *work = per_cpu_ptr(works, cpu); | 2580 | struct work_struct *work = per_cpu_ptr(works, cpu); |
842 | 2581 | ||
843 | INIT_WORK(work, func); | 2582 | INIT_WORK(work, func); |
844 | if (cpu != orig) | 2583 | schedule_work_on(cpu, work); |
845 | schedule_work_on(cpu, work); | ||
846 | } | 2584 | } |
847 | if (orig >= 0) | ||
848 | func(per_cpu_ptr(works, orig)); | ||
849 | 2585 | ||
850 | for_each_online_cpu(cpu) | 2586 | for_each_online_cpu(cpu) |
851 | flush_work(per_cpu_ptr(works, cpu)); | 2587 | flush_work(per_cpu_ptr(works, cpu)); |
@@ -881,7 +2617,7 @@ int schedule_on_each_cpu(work_func_t func) | |||
881 | */ | 2617 | */ |
882 | void flush_scheduled_work(void) | 2618 | void flush_scheduled_work(void) |
883 | { | 2619 | { |
884 | flush_workqueue(keventd_wq); | 2620 | flush_workqueue(system_wq); |
885 | } | 2621 | } |
886 | EXPORT_SYMBOL(flush_scheduled_work); | 2622 | EXPORT_SYMBOL(flush_scheduled_work); |
887 | 2623 | ||
@@ -913,170 +2649,170 @@ EXPORT_SYMBOL_GPL(execute_in_process_context); | |||
913 | 2649 | ||
914 | int keventd_up(void) | 2650 | int keventd_up(void) |
915 | { | 2651 | { |
916 | return keventd_wq != NULL; | 2652 | return system_wq != NULL; |
917 | } | 2653 | } |
918 | 2654 | ||
919 | int current_is_keventd(void) | 2655 | static int alloc_cwqs(struct workqueue_struct *wq) |
920 | { | 2656 | { |
921 | struct cpu_workqueue_struct *cwq; | 2657 | /* |
922 | int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ | 2658 | * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS. |
923 | int ret = 0; | 2659 | * Make sure that the alignment isn't lower than that of |
924 | 2660 | * unsigned long long. | |
925 | BUG_ON(!keventd_wq); | 2661 | */ |
2662 | const size_t size = sizeof(struct cpu_workqueue_struct); | ||
2663 | const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS, | ||
2664 | __alignof__(unsigned long long)); | ||
2665 | #ifdef CONFIG_SMP | ||
2666 | bool percpu = !(wq->flags & WQ_UNBOUND); | ||
2667 | #else | ||
2668 | bool percpu = false; | ||
2669 | #endif | ||
926 | 2670 | ||
927 | cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); | 2671 | if (percpu) |
928 | if (current == cwq->thread) | 2672 | wq->cpu_wq.pcpu = __alloc_percpu(size, align); |
929 | ret = 1; | 2673 | else { |
2674 | void *ptr; | ||
930 | 2675 | ||
931 | return ret; | 2676 | /* |
2677 | * Allocate enough room to align cwq and put an extra | ||
2678 | * pointer at the end pointing back to the originally | ||
2679 | * allocated pointer which will be used for free. | ||
2680 | */ | ||
2681 | ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL); | ||
2682 | if (ptr) { | ||
2683 | wq->cpu_wq.single = PTR_ALIGN(ptr, align); | ||
2684 | *(void **)(wq->cpu_wq.single + 1) = ptr; | ||
2685 | } | ||
2686 | } | ||
932 | 2687 | ||
2688 | /* just in case, make sure it's actually aligned */ | ||
2689 | BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align)); | ||
2690 | return wq->cpu_wq.v ? 0 : -ENOMEM; | ||
933 | } | 2691 | } |
934 | 2692 | ||
935 | static struct cpu_workqueue_struct * | 2693 | static void free_cwqs(struct workqueue_struct *wq) |
936 | init_cpu_workqueue(struct workqueue_struct *wq, int cpu) | ||
937 | { | 2694 | { |
938 | struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); | 2695 | #ifdef CONFIG_SMP |
939 | 2696 | bool percpu = !(wq->flags & WQ_UNBOUND); | |
940 | cwq->wq = wq; | 2697 | #else |
941 | spin_lock_init(&cwq->lock); | 2698 | bool percpu = false; |
942 | INIT_LIST_HEAD(&cwq->worklist); | 2699 | #endif |
943 | init_waitqueue_head(&cwq->more_work); | ||
944 | 2700 | ||
945 | return cwq; | 2701 | if (percpu) |
2702 | free_percpu(wq->cpu_wq.pcpu); | ||
2703 | else if (wq->cpu_wq.single) { | ||
2704 | /* the pointer to free is stored right after the cwq */ | ||
2705 | kfree(*(void **)(wq->cpu_wq.single + 1)); | ||
2706 | } | ||
946 | } | 2707 | } |
947 | 2708 | ||
948 | static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) | 2709 | static int wq_clamp_max_active(int max_active, unsigned int flags, |
2710 | const char *name) | ||
949 | { | 2711 | { |
950 | struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; | 2712 | int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE; |
951 | struct workqueue_struct *wq = cwq->wq; | ||
952 | const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d"; | ||
953 | struct task_struct *p; | ||
954 | 2713 | ||
955 | p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu); | 2714 | if (max_active < 1 || max_active > lim) |
956 | /* | 2715 | printk(KERN_WARNING "workqueue: max_active %d requested for %s " |
957 | * Nobody can add the work_struct to this cwq, | 2716 | "is out of range, clamping between %d and %d\n", |
958 | * if (caller is __create_workqueue) | 2717 | max_active, name, 1, lim); |
959 | * nobody should see this wq | ||
960 | * else // caller is CPU_UP_PREPARE | ||
961 | * cpu is not on cpu_online_map | ||
962 | * so we can abort safely. | ||
963 | */ | ||
964 | if (IS_ERR(p)) | ||
965 | return PTR_ERR(p); | ||
966 | if (cwq->wq->rt) | ||
967 | sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); | ||
968 | cwq->thread = p; | ||
969 | 2718 | ||
970 | trace_workqueue_creation(cwq->thread, cpu); | 2719 | return clamp_val(max_active, 1, lim); |
971 | |||
972 | return 0; | ||
973 | } | 2720 | } |
974 | 2721 | ||
975 | static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu) | 2722 | struct workqueue_struct *__alloc_workqueue_key(const char *name, |
2723 | unsigned int flags, | ||
2724 | int max_active, | ||
2725 | struct lock_class_key *key, | ||
2726 | const char *lock_name) | ||
976 | { | 2727 | { |
977 | struct task_struct *p = cwq->thread; | 2728 | struct workqueue_struct *wq; |
2729 | unsigned int cpu; | ||
978 | 2730 | ||
979 | if (p != NULL) { | 2731 | /* |
980 | if (cpu >= 0) | 2732 | * Unbound workqueues aren't concurrency managed and should be |
981 | kthread_bind(p, cpu); | 2733 | * dispatched to workers immediately. |
982 | wake_up_process(p); | 2734 | */ |
983 | } | 2735 | if (flags & WQ_UNBOUND) |
984 | } | 2736 | flags |= WQ_HIGHPRI; |
985 | 2737 | ||
986 | struct workqueue_struct *__create_workqueue_key(const char *name, | 2738 | max_active = max_active ?: WQ_DFL_ACTIVE; |
987 | int singlethread, | 2739 | max_active = wq_clamp_max_active(max_active, flags, name); |
988 | int freezeable, | ||
989 | int rt, | ||
990 | struct lock_class_key *key, | ||
991 | const char *lock_name) | ||
992 | { | ||
993 | struct workqueue_struct *wq; | ||
994 | struct cpu_workqueue_struct *cwq; | ||
995 | int err = 0, cpu; | ||
996 | 2740 | ||
997 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); | 2741 | wq = kzalloc(sizeof(*wq), GFP_KERNEL); |
998 | if (!wq) | 2742 | if (!wq) |
999 | return NULL; | 2743 | goto err; |
1000 | 2744 | ||
1001 | wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); | 2745 | wq->flags = flags; |
1002 | if (!wq->cpu_wq) { | 2746 | wq->saved_max_active = max_active; |
1003 | kfree(wq); | 2747 | mutex_init(&wq->flush_mutex); |
1004 | return NULL; | 2748 | atomic_set(&wq->nr_cwqs_to_flush, 0); |
1005 | } | 2749 | INIT_LIST_HEAD(&wq->flusher_queue); |
2750 | INIT_LIST_HEAD(&wq->flusher_overflow); | ||
1006 | 2751 | ||
1007 | wq->name = name; | 2752 | wq->name = name; |
1008 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); | 2753 | lockdep_init_map(&wq->lockdep_map, lock_name, key, 0); |
1009 | wq->singlethread = singlethread; | ||
1010 | wq->freezeable = freezeable; | ||
1011 | wq->rt = rt; | ||
1012 | INIT_LIST_HEAD(&wq->list); | 2754 | INIT_LIST_HEAD(&wq->list); |
1013 | 2755 | ||
1014 | if (singlethread) { | 2756 | if (alloc_cwqs(wq) < 0) |
1015 | cwq = init_cpu_workqueue(wq, singlethread_cpu); | 2757 | goto err; |
1016 | err = create_workqueue_thread(cwq, singlethread_cpu); | 2758 | |
1017 | start_workqueue_thread(cwq, -1); | 2759 | for_each_cwq_cpu(cpu, wq) { |
1018 | } else { | 2760 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
1019 | cpu_maps_update_begin(); | 2761 | struct global_cwq *gcwq = get_gcwq(cpu); |
1020 | /* | 2762 | |
1021 | * We must place this wq on list even if the code below fails. | 2763 | BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK); |
1022 | * cpu_down(cpu) can remove cpu from cpu_populated_map before | 2764 | cwq->gcwq = gcwq; |
1023 | * destroy_workqueue() takes the lock, in that case we leak | 2765 | cwq->wq = wq; |
1024 | * cwq[cpu]->thread. | 2766 | cwq->flush_color = -1; |
1025 | */ | 2767 | cwq->max_active = max_active; |
1026 | spin_lock(&workqueue_lock); | 2768 | INIT_LIST_HEAD(&cwq->delayed_works); |
1027 | list_add(&wq->list, &workqueues); | ||
1028 | spin_unlock(&workqueue_lock); | ||
1029 | /* | ||
1030 | * We must initialize cwqs for each possible cpu even if we | ||
1031 | * are going to call destroy_workqueue() finally. Otherwise | ||
1032 | * cpu_up() can hit the uninitialized cwq once we drop the | ||
1033 | * lock. | ||
1034 | */ | ||
1035 | for_each_possible_cpu(cpu) { | ||
1036 | cwq = init_cpu_workqueue(wq, cpu); | ||
1037 | if (err || !cpu_online(cpu)) | ||
1038 | continue; | ||
1039 | err = create_workqueue_thread(cwq, cpu); | ||
1040 | start_workqueue_thread(cwq, cpu); | ||
1041 | } | ||
1042 | cpu_maps_update_done(); | ||
1043 | } | 2769 | } |
1044 | 2770 | ||
1045 | if (err) { | 2771 | if (flags & WQ_RESCUER) { |
1046 | destroy_workqueue(wq); | 2772 | struct worker *rescuer; |
1047 | wq = NULL; | 2773 | |
2774 | if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL)) | ||
2775 | goto err; | ||
2776 | |||
2777 | wq->rescuer = rescuer = alloc_worker(); | ||
2778 | if (!rescuer) | ||
2779 | goto err; | ||
2780 | |||
2781 | rescuer->task = kthread_create(rescuer_thread, wq, "%s", name); | ||
2782 | if (IS_ERR(rescuer->task)) | ||
2783 | goto err; | ||
2784 | |||
2785 | wq->rescuer = rescuer; | ||
2786 | rescuer->task->flags |= PF_THREAD_BOUND; | ||
2787 | wake_up_process(rescuer->task); | ||
1048 | } | 2788 | } |
1049 | return wq; | ||
1050 | } | ||
1051 | EXPORT_SYMBOL_GPL(__create_workqueue_key); | ||
1052 | 2789 | ||
1053 | static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) | ||
1054 | { | ||
1055 | /* | 2790 | /* |
1056 | * Our caller is either destroy_workqueue() or CPU_POST_DEAD, | 2791 | * workqueue_lock protects global freeze state and workqueues |
1057 | * cpu_add_remove_lock protects cwq->thread. | 2792 | * list. Grab it, set max_active accordingly and add the new |
2793 | * workqueue to workqueues list. | ||
1058 | */ | 2794 | */ |
1059 | if (cwq->thread == NULL) | 2795 | spin_lock(&workqueue_lock); |
1060 | return; | ||
1061 | 2796 | ||
1062 | lock_map_acquire(&cwq->wq->lockdep_map); | 2797 | if (workqueue_freezing && wq->flags & WQ_FREEZEABLE) |
1063 | lock_map_release(&cwq->wq->lockdep_map); | 2798 | for_each_cwq_cpu(cpu, wq) |
2799 | get_cwq(cpu, wq)->max_active = 0; | ||
1064 | 2800 | ||
1065 | flush_cpu_workqueue(cwq); | 2801 | list_add(&wq->list, &workqueues); |
1066 | /* | 2802 | |
1067 | * If the caller is CPU_POST_DEAD and cwq->worklist was not empty, | 2803 | spin_unlock(&workqueue_lock); |
1068 | * a concurrent flush_workqueue() can insert a barrier after us. | 2804 | |
1069 | * However, in that case run_workqueue() won't return and check | 2805 | return wq; |
1070 | * kthread_should_stop() until it flushes all work_struct's. | 2806 | err: |
1071 | * When ->worklist becomes empty it is safe to exit because no | 2807 | if (wq) { |
1072 | * more work_structs can be queued on this cwq: flush_workqueue | 2808 | free_cwqs(wq); |
1073 | * checks list_empty(), and a "normal" queue_work() can't use | 2809 | free_mayday_mask(wq->mayday_mask); |
1074 | * a dead CPU. | 2810 | kfree(wq->rescuer); |
1075 | */ | 2811 | kfree(wq); |
1076 | trace_workqueue_destruction(cwq->thread); | 2812 | } |
1077 | kthread_stop(cwq->thread); | 2813 | return NULL; |
1078 | cwq->thread = NULL; | ||
1079 | } | 2814 | } |
2815 | EXPORT_SYMBOL_GPL(__alloc_workqueue_key); | ||
1080 | 2816 | ||
1081 | /** | 2817 | /** |
1082 | * destroy_workqueue - safely terminate a workqueue | 2818 | * destroy_workqueue - safely terminate a workqueue |
@@ -1086,72 +2822,516 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq) | |||
1086 | */ | 2822 | */ |
1087 | void destroy_workqueue(struct workqueue_struct *wq) | 2823 | void destroy_workqueue(struct workqueue_struct *wq) |
1088 | { | 2824 | { |
1089 | const struct cpumask *cpu_map = wq_cpu_map(wq); | 2825 | unsigned int cpu; |
1090 | int cpu; | ||
1091 | 2826 | ||
1092 | cpu_maps_update_begin(); | 2827 | flush_workqueue(wq); |
2828 | |||
2829 | /* | ||
2830 | * wq list is used to freeze wq, remove from list after | ||
2831 | * flushing is complete in case freeze races us. | ||
2832 | */ | ||
1093 | spin_lock(&workqueue_lock); | 2833 | spin_lock(&workqueue_lock); |
1094 | list_del(&wq->list); | 2834 | list_del(&wq->list); |
1095 | spin_unlock(&workqueue_lock); | 2835 | spin_unlock(&workqueue_lock); |
1096 | 2836 | ||
1097 | for_each_cpu(cpu, cpu_map) | 2837 | /* sanity check */ |
1098 | cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu)); | 2838 | for_each_cwq_cpu(cpu, wq) { |
1099 | cpu_maps_update_done(); | 2839 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); |
2840 | int i; | ||
2841 | |||
2842 | for (i = 0; i < WORK_NR_COLORS; i++) | ||
2843 | BUG_ON(cwq->nr_in_flight[i]); | ||
2844 | BUG_ON(cwq->nr_active); | ||
2845 | BUG_ON(!list_empty(&cwq->delayed_works)); | ||
2846 | } | ||
2847 | |||
2848 | if (wq->flags & WQ_RESCUER) { | ||
2849 | kthread_stop(wq->rescuer->task); | ||
2850 | free_mayday_mask(wq->mayday_mask); | ||
2851 | } | ||
1100 | 2852 | ||
1101 | free_percpu(wq->cpu_wq); | 2853 | free_cwqs(wq); |
1102 | kfree(wq); | 2854 | kfree(wq); |
1103 | } | 2855 | } |
1104 | EXPORT_SYMBOL_GPL(destroy_workqueue); | 2856 | EXPORT_SYMBOL_GPL(destroy_workqueue); |
1105 | 2857 | ||
2858 | /** | ||
2859 | * workqueue_set_max_active - adjust max_active of a workqueue | ||
2860 | * @wq: target workqueue | ||
2861 | * @max_active: new max_active value. | ||
2862 | * | ||
2863 | * Set max_active of @wq to @max_active. | ||
2864 | * | ||
2865 | * CONTEXT: | ||
2866 | * Don't call from IRQ context. | ||
2867 | */ | ||
2868 | void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) | ||
2869 | { | ||
2870 | unsigned int cpu; | ||
2871 | |||
2872 | max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); | ||
2873 | |||
2874 | spin_lock(&workqueue_lock); | ||
2875 | |||
2876 | wq->saved_max_active = max_active; | ||
2877 | |||
2878 | for_each_cwq_cpu(cpu, wq) { | ||
2879 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
2880 | |||
2881 | spin_lock_irq(&gcwq->lock); | ||
2882 | |||
2883 | if (!(wq->flags & WQ_FREEZEABLE) || | ||
2884 | !(gcwq->flags & GCWQ_FREEZING)) | ||
2885 | get_cwq(gcwq->cpu, wq)->max_active = max_active; | ||
2886 | |||
2887 | spin_unlock_irq(&gcwq->lock); | ||
2888 | } | ||
2889 | |||
2890 | spin_unlock(&workqueue_lock); | ||
2891 | } | ||
2892 | EXPORT_SYMBOL_GPL(workqueue_set_max_active); | ||
2893 | |||
2894 | /** | ||
2895 | * workqueue_congested - test whether a workqueue is congested | ||
2896 | * @cpu: CPU in question | ||
2897 | * @wq: target workqueue | ||
2898 | * | ||
2899 | * Test whether @wq's cpu workqueue for @cpu is congested. There is | ||
2900 | * no synchronization around this function and the test result is | ||
2901 | * unreliable and only useful as advisory hints or for debugging. | ||
2902 | * | ||
2903 | * RETURNS: | ||
2904 | * %true if congested, %false otherwise. | ||
2905 | */ | ||
2906 | bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq) | ||
2907 | { | ||
2908 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | ||
2909 | |||
2910 | return !list_empty(&cwq->delayed_works); | ||
2911 | } | ||
2912 | EXPORT_SYMBOL_GPL(workqueue_congested); | ||
2913 | |||
2914 | /** | ||
2915 | * work_cpu - return the last known associated cpu for @work | ||
2916 | * @work: the work of interest | ||
2917 | * | ||
2918 | * RETURNS: | ||
2919 | * CPU number if @work was ever queued. WORK_CPU_NONE otherwise. | ||
2920 | */ | ||
2921 | unsigned int work_cpu(struct work_struct *work) | ||
2922 | { | ||
2923 | struct global_cwq *gcwq = get_work_gcwq(work); | ||
2924 | |||
2925 | return gcwq ? gcwq->cpu : WORK_CPU_NONE; | ||
2926 | } | ||
2927 | EXPORT_SYMBOL_GPL(work_cpu); | ||
2928 | |||
2929 | /** | ||
2930 | * work_busy - test whether a work is currently pending or running | ||
2931 | * @work: the work to be tested | ||
2932 | * | ||
2933 | * Test whether @work is currently pending or running. There is no | ||
2934 | * synchronization around this function and the test result is | ||
2935 | * unreliable and only useful as advisory hints or for debugging. | ||
2936 | * Especially for reentrant wqs, the pending state might hide the | ||
2937 | * running state. | ||
2938 | * | ||
2939 | * RETURNS: | ||
2940 | * OR'd bitmask of WORK_BUSY_* bits. | ||
2941 | */ | ||
2942 | unsigned int work_busy(struct work_struct *work) | ||
2943 | { | ||
2944 | struct global_cwq *gcwq = get_work_gcwq(work); | ||
2945 | unsigned long flags; | ||
2946 | unsigned int ret = 0; | ||
2947 | |||
2948 | if (!gcwq) | ||
2949 | return false; | ||
2950 | |||
2951 | spin_lock_irqsave(&gcwq->lock, flags); | ||
2952 | |||
2953 | if (work_pending(work)) | ||
2954 | ret |= WORK_BUSY_PENDING; | ||
2955 | if (find_worker_executing_work(gcwq, work)) | ||
2956 | ret |= WORK_BUSY_RUNNING; | ||
2957 | |||
2958 | spin_unlock_irqrestore(&gcwq->lock, flags); | ||
2959 | |||
2960 | return ret; | ||
2961 | } | ||
2962 | EXPORT_SYMBOL_GPL(work_busy); | ||
2963 | |||
2964 | /* | ||
2965 | * CPU hotplug. | ||
2966 | * | ||
2967 | * There are two challenges in supporting CPU hotplug. Firstly, there | ||
2968 | * are a lot of assumptions on strong associations among work, cwq and | ||
2969 | * gcwq which make migrating pending and scheduled works very | ||
2970 | * difficult to implement without impacting hot paths. Secondly, | ||
2971 | * gcwqs serve mix of short, long and very long running works making | ||
2972 | * blocked draining impractical. | ||
2973 | * | ||
2974 | * This is solved by allowing a gcwq to be detached from CPU, running | ||
2975 | * it with unbound (rogue) workers and allowing it to be reattached | ||
2976 | * later if the cpu comes back online. A separate thread is created | ||
2977 | * to govern a gcwq in such state and is called the trustee of the | ||
2978 | * gcwq. | ||
2979 | * | ||
2980 | * Trustee states and their descriptions. | ||
2981 | * | ||
2982 | * START Command state used on startup. On CPU_DOWN_PREPARE, a | ||
2983 | * new trustee is started with this state. | ||
2984 | * | ||
2985 | * IN_CHARGE Once started, trustee will enter this state after | ||
2986 | * assuming the manager role and making all existing | ||
2987 | * workers rogue. DOWN_PREPARE waits for trustee to | ||
2988 | * enter this state. After reaching IN_CHARGE, trustee | ||
2989 | * tries to execute the pending worklist until it's empty | ||
2990 | * and the state is set to BUTCHER, or the state is set | ||
2991 | * to RELEASE. | ||
2992 | * | ||
2993 | * BUTCHER Command state which is set by the cpu callback after | ||
2994 | * the cpu has went down. Once this state is set trustee | ||
2995 | * knows that there will be no new works on the worklist | ||
2996 | * and once the worklist is empty it can proceed to | ||
2997 | * killing idle workers. | ||
2998 | * | ||
2999 | * RELEASE Command state which is set by the cpu callback if the | ||
3000 | * cpu down has been canceled or it has come online | ||
3001 | * again. After recognizing this state, trustee stops | ||
3002 | * trying to drain or butcher and clears ROGUE, rebinds | ||
3003 | * all remaining workers back to the cpu and releases | ||
3004 | * manager role. | ||
3005 | * | ||
3006 | * DONE Trustee will enter this state after BUTCHER or RELEASE | ||
3007 | * is complete. | ||
3008 | * | ||
3009 | * trustee CPU draining | ||
3010 | * took over down complete | ||
3011 | * START -----------> IN_CHARGE -----------> BUTCHER -----------> DONE | ||
3012 | * | | ^ | ||
3013 | * | CPU is back online v return workers | | ||
3014 | * ----------------> RELEASE -------------- | ||
3015 | */ | ||
3016 | |||
3017 | /** | ||
3018 | * trustee_wait_event_timeout - timed event wait for trustee | ||
3019 | * @cond: condition to wait for | ||
3020 | * @timeout: timeout in jiffies | ||
3021 | * | ||
3022 | * wait_event_timeout() for trustee to use. Handles locking and | ||
3023 | * checks for RELEASE request. | ||
3024 | * | ||
3025 | * CONTEXT: | ||
3026 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
3027 | * multiple times. To be used by trustee. | ||
3028 | * | ||
3029 | * RETURNS: | ||
3030 | * Positive indicating left time if @cond is satisfied, 0 if timed | ||
3031 | * out, -1 if canceled. | ||
3032 | */ | ||
3033 | #define trustee_wait_event_timeout(cond, timeout) ({ \ | ||
3034 | long __ret = (timeout); \ | ||
3035 | while (!((cond) || (gcwq->trustee_state == TRUSTEE_RELEASE)) && \ | ||
3036 | __ret) { \ | ||
3037 | spin_unlock_irq(&gcwq->lock); \ | ||
3038 | __wait_event_timeout(gcwq->trustee_wait, (cond) || \ | ||
3039 | (gcwq->trustee_state == TRUSTEE_RELEASE), \ | ||
3040 | __ret); \ | ||
3041 | spin_lock_irq(&gcwq->lock); \ | ||
3042 | } \ | ||
3043 | gcwq->trustee_state == TRUSTEE_RELEASE ? -1 : (__ret); \ | ||
3044 | }) | ||
3045 | |||
3046 | /** | ||
3047 | * trustee_wait_event - event wait for trustee | ||
3048 | * @cond: condition to wait for | ||
3049 | * | ||
3050 | * wait_event() for trustee to use. Automatically handles locking and | ||
3051 | * checks for CANCEL request. | ||
3052 | * | ||
3053 | * CONTEXT: | ||
3054 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
3055 | * multiple times. To be used by trustee. | ||
3056 | * | ||
3057 | * RETURNS: | ||
3058 | * 0 if @cond is satisfied, -1 if canceled. | ||
3059 | */ | ||
3060 | #define trustee_wait_event(cond) ({ \ | ||
3061 | long __ret1; \ | ||
3062 | __ret1 = trustee_wait_event_timeout(cond, MAX_SCHEDULE_TIMEOUT);\ | ||
3063 | __ret1 < 0 ? -1 : 0; \ | ||
3064 | }) | ||
3065 | |||
3066 | static int __cpuinit trustee_thread(void *__gcwq) | ||
3067 | { | ||
3068 | struct global_cwq *gcwq = __gcwq; | ||
3069 | struct worker *worker; | ||
3070 | struct work_struct *work; | ||
3071 | struct hlist_node *pos; | ||
3072 | long rc; | ||
3073 | int i; | ||
3074 | |||
3075 | BUG_ON(gcwq->cpu != smp_processor_id()); | ||
3076 | |||
3077 | spin_lock_irq(&gcwq->lock); | ||
3078 | /* | ||
3079 | * Claim the manager position and make all workers rogue. | ||
3080 | * Trustee must be bound to the target cpu and can't be | ||
3081 | * cancelled. | ||
3082 | */ | ||
3083 | BUG_ON(gcwq->cpu != smp_processor_id()); | ||
3084 | rc = trustee_wait_event(!(gcwq->flags & GCWQ_MANAGING_WORKERS)); | ||
3085 | BUG_ON(rc < 0); | ||
3086 | |||
3087 | gcwq->flags |= GCWQ_MANAGING_WORKERS; | ||
3088 | |||
3089 | list_for_each_entry(worker, &gcwq->idle_list, entry) | ||
3090 | worker->flags |= WORKER_ROGUE; | ||
3091 | |||
3092 | for_each_busy_worker(worker, i, pos, gcwq) | ||
3093 | worker->flags |= WORKER_ROGUE; | ||
3094 | |||
3095 | /* | ||
3096 | * Call schedule() so that we cross rq->lock and thus can | ||
3097 | * guarantee sched callbacks see the rogue flag. This is | ||
3098 | * necessary as scheduler callbacks may be invoked from other | ||
3099 | * cpus. | ||
3100 | */ | ||
3101 | spin_unlock_irq(&gcwq->lock); | ||
3102 | schedule(); | ||
3103 | spin_lock_irq(&gcwq->lock); | ||
3104 | |||
3105 | /* | ||
3106 | * Sched callbacks are disabled now. Zap nr_running. After | ||
3107 | * this, nr_running stays zero and need_more_worker() and | ||
3108 | * keep_working() are always true as long as the worklist is | ||
3109 | * not empty. | ||
3110 | */ | ||
3111 | atomic_set(get_gcwq_nr_running(gcwq->cpu), 0); | ||
3112 | |||
3113 | spin_unlock_irq(&gcwq->lock); | ||
3114 | del_timer_sync(&gcwq->idle_timer); | ||
3115 | spin_lock_irq(&gcwq->lock); | ||
3116 | |||
3117 | /* | ||
3118 | * We're now in charge. Notify and proceed to drain. We need | ||
3119 | * to keep the gcwq running during the whole CPU down | ||
3120 | * procedure as other cpu hotunplug callbacks may need to | ||
3121 | * flush currently running tasks. | ||
3122 | */ | ||
3123 | gcwq->trustee_state = TRUSTEE_IN_CHARGE; | ||
3124 | wake_up_all(&gcwq->trustee_wait); | ||
3125 | |||
3126 | /* | ||
3127 | * The original cpu is in the process of dying and may go away | ||
3128 | * anytime now. When that happens, we and all workers would | ||
3129 | * be migrated to other cpus. Try draining any left work. We | ||
3130 | * want to get it over with ASAP - spam rescuers, wake up as | ||
3131 | * many idlers as necessary and create new ones till the | ||
3132 | * worklist is empty. Note that if the gcwq is frozen, there | ||
3133 | * may be frozen works in freezeable cwqs. Don't declare | ||
3134 | * completion while frozen. | ||
3135 | */ | ||
3136 | while (gcwq->nr_workers != gcwq->nr_idle || | ||
3137 | gcwq->flags & GCWQ_FREEZING || | ||
3138 | gcwq->trustee_state == TRUSTEE_IN_CHARGE) { | ||
3139 | int nr_works = 0; | ||
3140 | |||
3141 | list_for_each_entry(work, &gcwq->worklist, entry) { | ||
3142 | send_mayday(work); | ||
3143 | nr_works++; | ||
3144 | } | ||
3145 | |||
3146 | list_for_each_entry(worker, &gcwq->idle_list, entry) { | ||
3147 | if (!nr_works--) | ||
3148 | break; | ||
3149 | wake_up_process(worker->task); | ||
3150 | } | ||
3151 | |||
3152 | if (need_to_create_worker(gcwq)) { | ||
3153 | spin_unlock_irq(&gcwq->lock); | ||
3154 | worker = create_worker(gcwq, false); | ||
3155 | spin_lock_irq(&gcwq->lock); | ||
3156 | if (worker) { | ||
3157 | worker->flags |= WORKER_ROGUE; | ||
3158 | start_worker(worker); | ||
3159 | } | ||
3160 | } | ||
3161 | |||
3162 | /* give a breather */ | ||
3163 | if (trustee_wait_event_timeout(false, TRUSTEE_COOLDOWN) < 0) | ||
3164 | break; | ||
3165 | } | ||
3166 | |||
3167 | /* | ||
3168 | * Either all works have been scheduled and cpu is down, or | ||
3169 | * cpu down has already been canceled. Wait for and butcher | ||
3170 | * all workers till we're canceled. | ||
3171 | */ | ||
3172 | do { | ||
3173 | rc = trustee_wait_event(!list_empty(&gcwq->idle_list)); | ||
3174 | while (!list_empty(&gcwq->idle_list)) | ||
3175 | destroy_worker(list_first_entry(&gcwq->idle_list, | ||
3176 | struct worker, entry)); | ||
3177 | } while (gcwq->nr_workers && rc >= 0); | ||
3178 | |||
3179 | /* | ||
3180 | * At this point, either draining has completed and no worker | ||
3181 | * is left, or cpu down has been canceled or the cpu is being | ||
3182 | * brought back up. There shouldn't be any idle one left. | ||
3183 | * Tell the remaining busy ones to rebind once it finishes the | ||
3184 | * currently scheduled works by scheduling the rebind_work. | ||
3185 | */ | ||
3186 | WARN_ON(!list_empty(&gcwq->idle_list)); | ||
3187 | |||
3188 | for_each_busy_worker(worker, i, pos, gcwq) { | ||
3189 | struct work_struct *rebind_work = &worker->rebind_work; | ||
3190 | |||
3191 | /* | ||
3192 | * Rebind_work may race with future cpu hotplug | ||
3193 | * operations. Use a separate flag to mark that | ||
3194 | * rebinding is scheduled. | ||
3195 | */ | ||
3196 | worker->flags |= WORKER_REBIND; | ||
3197 | worker->flags &= ~WORKER_ROGUE; | ||
3198 | |||
3199 | /* queue rebind_work, wq doesn't matter, use the default one */ | ||
3200 | if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, | ||
3201 | work_data_bits(rebind_work))) | ||
3202 | continue; | ||
3203 | |||
3204 | debug_work_activate(rebind_work); | ||
3205 | insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work, | ||
3206 | worker->scheduled.next, | ||
3207 | work_color_to_flags(WORK_NO_COLOR)); | ||
3208 | } | ||
3209 | |||
3210 | /* relinquish manager role */ | ||
3211 | gcwq->flags &= ~GCWQ_MANAGING_WORKERS; | ||
3212 | |||
3213 | /* notify completion */ | ||
3214 | gcwq->trustee = NULL; | ||
3215 | gcwq->trustee_state = TRUSTEE_DONE; | ||
3216 | wake_up_all(&gcwq->trustee_wait); | ||
3217 | spin_unlock_irq(&gcwq->lock); | ||
3218 | return 0; | ||
3219 | } | ||
3220 | |||
3221 | /** | ||
3222 | * wait_trustee_state - wait for trustee to enter the specified state | ||
3223 | * @gcwq: gcwq the trustee of interest belongs to | ||
3224 | * @state: target state to wait for | ||
3225 | * | ||
3226 | * Wait for the trustee to reach @state. DONE is already matched. | ||
3227 | * | ||
3228 | * CONTEXT: | ||
3229 | * spin_lock_irq(gcwq->lock) which may be released and regrabbed | ||
3230 | * multiple times. To be used by cpu_callback. | ||
3231 | */ | ||
3232 | static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state) | ||
3233 | { | ||
3234 | if (!(gcwq->trustee_state == state || | ||
3235 | gcwq->trustee_state == TRUSTEE_DONE)) { | ||
3236 | spin_unlock_irq(&gcwq->lock); | ||
3237 | __wait_event(gcwq->trustee_wait, | ||
3238 | gcwq->trustee_state == state || | ||
3239 | gcwq->trustee_state == TRUSTEE_DONE); | ||
3240 | spin_lock_irq(&gcwq->lock); | ||
3241 | } | ||
3242 | } | ||
3243 | |||
1106 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, | 3244 | static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, |
1107 | unsigned long action, | 3245 | unsigned long action, |
1108 | void *hcpu) | 3246 | void *hcpu) |
1109 | { | 3247 | { |
1110 | unsigned int cpu = (unsigned long)hcpu; | 3248 | unsigned int cpu = (unsigned long)hcpu; |
1111 | struct cpu_workqueue_struct *cwq; | 3249 | struct global_cwq *gcwq = get_gcwq(cpu); |
1112 | struct workqueue_struct *wq; | 3250 | struct task_struct *new_trustee = NULL; |
1113 | int err = 0; | 3251 | struct worker *uninitialized_var(new_worker); |
3252 | unsigned long flags; | ||
1114 | 3253 | ||
1115 | action &= ~CPU_TASKS_FROZEN; | 3254 | action &= ~CPU_TASKS_FROZEN; |
1116 | 3255 | ||
1117 | switch (action) { | 3256 | switch (action) { |
3257 | case CPU_DOWN_PREPARE: | ||
3258 | new_trustee = kthread_create(trustee_thread, gcwq, | ||
3259 | "workqueue_trustee/%d\n", cpu); | ||
3260 | if (IS_ERR(new_trustee)) | ||
3261 | return notifier_from_errno(PTR_ERR(new_trustee)); | ||
3262 | kthread_bind(new_trustee, cpu); | ||
3263 | /* fall through */ | ||
1118 | case CPU_UP_PREPARE: | 3264 | case CPU_UP_PREPARE: |
1119 | cpumask_set_cpu(cpu, cpu_populated_map); | 3265 | BUG_ON(gcwq->first_idle); |
1120 | } | 3266 | new_worker = create_worker(gcwq, false); |
1121 | undo: | 3267 | if (!new_worker) { |
1122 | list_for_each_entry(wq, &workqueues, list) { | 3268 | if (new_trustee) |
1123 | cwq = per_cpu_ptr(wq->cpu_wq, cpu); | 3269 | kthread_stop(new_trustee); |
1124 | 3270 | return NOTIFY_BAD; | |
1125 | switch (action) { | ||
1126 | case CPU_UP_PREPARE: | ||
1127 | err = create_workqueue_thread(cwq, cpu); | ||
1128 | if (!err) | ||
1129 | break; | ||
1130 | printk(KERN_ERR "workqueue [%s] for %i failed\n", | ||
1131 | wq->name, cpu); | ||
1132 | action = CPU_UP_CANCELED; | ||
1133 | err = -ENOMEM; | ||
1134 | goto undo; | ||
1135 | |||
1136 | case CPU_ONLINE: | ||
1137 | start_workqueue_thread(cwq, cpu); | ||
1138 | break; | ||
1139 | |||
1140 | case CPU_UP_CANCELED: | ||
1141 | start_workqueue_thread(cwq, -1); | ||
1142 | case CPU_POST_DEAD: | ||
1143 | cleanup_workqueue_thread(cwq); | ||
1144 | break; | ||
1145 | } | 3271 | } |
1146 | } | 3272 | } |
1147 | 3273 | ||
3274 | /* some are called w/ irq disabled, don't disturb irq status */ | ||
3275 | spin_lock_irqsave(&gcwq->lock, flags); | ||
3276 | |||
1148 | switch (action) { | 3277 | switch (action) { |
1149 | case CPU_UP_CANCELED: | 3278 | case CPU_DOWN_PREPARE: |
3279 | /* initialize trustee and tell it to acquire the gcwq */ | ||
3280 | BUG_ON(gcwq->trustee || gcwq->trustee_state != TRUSTEE_DONE); | ||
3281 | gcwq->trustee = new_trustee; | ||
3282 | gcwq->trustee_state = TRUSTEE_START; | ||
3283 | wake_up_process(gcwq->trustee); | ||
3284 | wait_trustee_state(gcwq, TRUSTEE_IN_CHARGE); | ||
3285 | /* fall through */ | ||
3286 | case CPU_UP_PREPARE: | ||
3287 | BUG_ON(gcwq->first_idle); | ||
3288 | gcwq->first_idle = new_worker; | ||
3289 | break; | ||
3290 | |||
3291 | case CPU_DYING: | ||
3292 | /* | ||
3293 | * Before this, the trustee and all workers except for | ||
3294 | * the ones which are still executing works from | ||
3295 | * before the last CPU down must be on the cpu. After | ||
3296 | * this, they'll all be diasporas. | ||
3297 | */ | ||
3298 | gcwq->flags |= GCWQ_DISASSOCIATED; | ||
3299 | break; | ||
3300 | |||
1150 | case CPU_POST_DEAD: | 3301 | case CPU_POST_DEAD: |
1151 | cpumask_clear_cpu(cpu, cpu_populated_map); | 3302 | gcwq->trustee_state = TRUSTEE_BUTCHER; |
3303 | /* fall through */ | ||
3304 | case CPU_UP_CANCELED: | ||
3305 | destroy_worker(gcwq->first_idle); | ||
3306 | gcwq->first_idle = NULL; | ||
3307 | break; | ||
3308 | |||
3309 | case CPU_DOWN_FAILED: | ||
3310 | case CPU_ONLINE: | ||
3311 | gcwq->flags &= ~GCWQ_DISASSOCIATED; | ||
3312 | if (gcwq->trustee_state != TRUSTEE_DONE) { | ||
3313 | gcwq->trustee_state = TRUSTEE_RELEASE; | ||
3314 | wake_up_process(gcwq->trustee); | ||
3315 | wait_trustee_state(gcwq, TRUSTEE_DONE); | ||
3316 | } | ||
3317 | |||
3318 | /* | ||
3319 | * Trustee is done and there might be no worker left. | ||
3320 | * Put the first_idle in and request a real manager to | ||
3321 | * take a look. | ||
3322 | */ | ||
3323 | spin_unlock_irq(&gcwq->lock); | ||
3324 | kthread_bind(gcwq->first_idle->task, cpu); | ||
3325 | spin_lock_irq(&gcwq->lock); | ||
3326 | gcwq->flags |= GCWQ_MANAGE_WORKERS; | ||
3327 | start_worker(gcwq->first_idle); | ||
3328 | gcwq->first_idle = NULL; | ||
3329 | break; | ||
1152 | } | 3330 | } |
1153 | 3331 | ||
1154 | return notifier_from_errno(err); | 3332 | spin_unlock_irqrestore(&gcwq->lock, flags); |
3333 | |||
3334 | return notifier_from_errno(0); | ||
1155 | } | 3335 | } |
1156 | 3336 | ||
1157 | #ifdef CONFIG_SMP | 3337 | #ifdef CONFIG_SMP |
@@ -1201,14 +3381,199 @@ long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) | |||
1201 | EXPORT_SYMBOL_GPL(work_on_cpu); | 3381 | EXPORT_SYMBOL_GPL(work_on_cpu); |
1202 | #endif /* CONFIG_SMP */ | 3382 | #endif /* CONFIG_SMP */ |
1203 | 3383 | ||
1204 | void __init init_workqueues(void) | 3384 | #ifdef CONFIG_FREEZER |
3385 | |||
3386 | /** | ||
3387 | * freeze_workqueues_begin - begin freezing workqueues | ||
3388 | * | ||
3389 | * Start freezing workqueues. After this function returns, all | ||
3390 | * freezeable workqueues will queue new works to their frozen_works | ||
3391 | * list instead of gcwq->worklist. | ||
3392 | * | ||
3393 | * CONTEXT: | ||
3394 | * Grabs and releases workqueue_lock and gcwq->lock's. | ||
3395 | */ | ||
3396 | void freeze_workqueues_begin(void) | ||
1205 | { | 3397 | { |
1206 | alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL); | 3398 | unsigned int cpu; |
1207 | 3399 | ||
1208 | cpumask_copy(cpu_populated_map, cpu_online_mask); | 3400 | spin_lock(&workqueue_lock); |
1209 | singlethread_cpu = cpumask_first(cpu_possible_mask); | 3401 | |
1210 | cpu_singlethread_map = cpumask_of(singlethread_cpu); | 3402 | BUG_ON(workqueue_freezing); |
1211 | hotcpu_notifier(workqueue_cpu_callback, 0); | 3403 | workqueue_freezing = true; |
1212 | keventd_wq = create_workqueue("events"); | 3404 | |
1213 | BUG_ON(!keventd_wq); | 3405 | for_each_gcwq_cpu(cpu) { |
3406 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
3407 | struct workqueue_struct *wq; | ||
3408 | |||
3409 | spin_lock_irq(&gcwq->lock); | ||
3410 | |||
3411 | BUG_ON(gcwq->flags & GCWQ_FREEZING); | ||
3412 | gcwq->flags |= GCWQ_FREEZING; | ||
3413 | |||
3414 | list_for_each_entry(wq, &workqueues, list) { | ||
3415 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | ||
3416 | |||
3417 | if (cwq && wq->flags & WQ_FREEZEABLE) | ||
3418 | cwq->max_active = 0; | ||
3419 | } | ||
3420 | |||
3421 | spin_unlock_irq(&gcwq->lock); | ||
3422 | } | ||
3423 | |||
3424 | spin_unlock(&workqueue_lock); | ||
3425 | } | ||
3426 | |||
3427 | /** | ||
3428 | * freeze_workqueues_busy - are freezeable workqueues still busy? | ||
3429 | * | ||
3430 | * Check whether freezing is complete. This function must be called | ||
3431 | * between freeze_workqueues_begin() and thaw_workqueues(). | ||
3432 | * | ||
3433 | * CONTEXT: | ||
3434 | * Grabs and releases workqueue_lock. | ||
3435 | * | ||
3436 | * RETURNS: | ||
3437 | * %true if some freezeable workqueues are still busy. %false if | ||
3438 | * freezing is complete. | ||
3439 | */ | ||
3440 | bool freeze_workqueues_busy(void) | ||
3441 | { | ||
3442 | unsigned int cpu; | ||
3443 | bool busy = false; | ||
3444 | |||
3445 | spin_lock(&workqueue_lock); | ||
3446 | |||
3447 | BUG_ON(!workqueue_freezing); | ||
3448 | |||
3449 | for_each_gcwq_cpu(cpu) { | ||
3450 | struct workqueue_struct *wq; | ||
3451 | /* | ||
3452 | * nr_active is monotonically decreasing. It's safe | ||
3453 | * to peek without lock. | ||
3454 | */ | ||
3455 | list_for_each_entry(wq, &workqueues, list) { | ||
3456 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | ||
3457 | |||
3458 | if (!cwq || !(wq->flags & WQ_FREEZEABLE)) | ||
3459 | continue; | ||
3460 | |||
3461 | BUG_ON(cwq->nr_active < 0); | ||
3462 | if (cwq->nr_active) { | ||
3463 | busy = true; | ||
3464 | goto out_unlock; | ||
3465 | } | ||
3466 | } | ||
3467 | } | ||
3468 | out_unlock: | ||
3469 | spin_unlock(&workqueue_lock); | ||
3470 | return busy; | ||
3471 | } | ||
3472 | |||
3473 | /** | ||
3474 | * thaw_workqueues - thaw workqueues | ||
3475 | * | ||
3476 | * Thaw workqueues. Normal queueing is restored and all collected | ||
3477 | * frozen works are transferred to their respective gcwq worklists. | ||
3478 | * | ||
3479 | * CONTEXT: | ||
3480 | * Grabs and releases workqueue_lock and gcwq->lock's. | ||
3481 | */ | ||
3482 | void thaw_workqueues(void) | ||
3483 | { | ||
3484 | unsigned int cpu; | ||
3485 | |||
3486 | spin_lock(&workqueue_lock); | ||
3487 | |||
3488 | if (!workqueue_freezing) | ||
3489 | goto out_unlock; | ||
3490 | |||
3491 | for_each_gcwq_cpu(cpu) { | ||
3492 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
3493 | struct workqueue_struct *wq; | ||
3494 | |||
3495 | spin_lock_irq(&gcwq->lock); | ||
3496 | |||
3497 | BUG_ON(!(gcwq->flags & GCWQ_FREEZING)); | ||
3498 | gcwq->flags &= ~GCWQ_FREEZING; | ||
3499 | |||
3500 | list_for_each_entry(wq, &workqueues, list) { | ||
3501 | struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); | ||
3502 | |||
3503 | if (!cwq || !(wq->flags & WQ_FREEZEABLE)) | ||
3504 | continue; | ||
3505 | |||
3506 | /* restore max_active and repopulate worklist */ | ||
3507 | cwq->max_active = wq->saved_max_active; | ||
3508 | |||
3509 | while (!list_empty(&cwq->delayed_works) && | ||
3510 | cwq->nr_active < cwq->max_active) | ||
3511 | cwq_activate_first_delayed(cwq); | ||
3512 | } | ||
3513 | |||
3514 | wake_up_worker(gcwq); | ||
3515 | |||
3516 | spin_unlock_irq(&gcwq->lock); | ||
3517 | } | ||
3518 | |||
3519 | workqueue_freezing = false; | ||
3520 | out_unlock: | ||
3521 | spin_unlock(&workqueue_lock); | ||
3522 | } | ||
3523 | #endif /* CONFIG_FREEZER */ | ||
3524 | |||
3525 | static int __init init_workqueues(void) | ||
3526 | { | ||
3527 | unsigned int cpu; | ||
3528 | int i; | ||
3529 | |||
3530 | cpu_notifier(workqueue_cpu_callback, CPU_PRI_WORKQUEUE); | ||
3531 | |||
3532 | /* initialize gcwqs */ | ||
3533 | for_each_gcwq_cpu(cpu) { | ||
3534 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
3535 | |||
3536 | spin_lock_init(&gcwq->lock); | ||
3537 | INIT_LIST_HEAD(&gcwq->worklist); | ||
3538 | gcwq->cpu = cpu; | ||
3539 | if (cpu == WORK_CPU_UNBOUND) | ||
3540 | gcwq->flags |= GCWQ_DISASSOCIATED; | ||
3541 | |||
3542 | INIT_LIST_HEAD(&gcwq->idle_list); | ||
3543 | for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) | ||
3544 | INIT_HLIST_HEAD(&gcwq->busy_hash[i]); | ||
3545 | |||
3546 | init_timer_deferrable(&gcwq->idle_timer); | ||
3547 | gcwq->idle_timer.function = idle_worker_timeout; | ||
3548 | gcwq->idle_timer.data = (unsigned long)gcwq; | ||
3549 | |||
3550 | setup_timer(&gcwq->mayday_timer, gcwq_mayday_timeout, | ||
3551 | (unsigned long)gcwq); | ||
3552 | |||
3553 | ida_init(&gcwq->worker_ida); | ||
3554 | |||
3555 | gcwq->trustee_state = TRUSTEE_DONE; | ||
3556 | init_waitqueue_head(&gcwq->trustee_wait); | ||
3557 | } | ||
3558 | |||
3559 | /* create the initial worker */ | ||
3560 | for_each_online_gcwq_cpu(cpu) { | ||
3561 | struct global_cwq *gcwq = get_gcwq(cpu); | ||
3562 | struct worker *worker; | ||
3563 | |||
3564 | worker = create_worker(gcwq, true); | ||
3565 | BUG_ON(!worker); | ||
3566 | spin_lock_irq(&gcwq->lock); | ||
3567 | start_worker(worker); | ||
3568 | spin_unlock_irq(&gcwq->lock); | ||
3569 | } | ||
3570 | |||
3571 | system_wq = alloc_workqueue("events", 0, 0); | ||
3572 | system_long_wq = alloc_workqueue("events_long", 0, 0); | ||
3573 | system_nrt_wq = alloc_workqueue("events_nrt", WQ_NON_REENTRANT, 0); | ||
3574 | system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, | ||
3575 | WQ_UNBOUND_MAX_ACTIVE); | ||
3576 | BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq); | ||
3577 | return 0; | ||
1214 | } | 3578 | } |
3579 | early_initcall(init_workqueues); | ||