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-rw-r--r--kernel/cpu.c5
-rw-r--r--kernel/hrtimer.c3
-rw-r--r--kernel/posix-cpu-timers.c5
-rw-r--r--kernel/time.c1
-rw-r--r--kernel/time/clockevents.c13
-rw-r--r--kernel/time/clocksource.c97
-rw-r--r--kernel/time/tick-oneshot.c4
-rw-r--r--kernel/time/tick-sched.c141
-rw-r--r--kernel/time/timekeeping.c119
-rw-r--r--kernel/time/timer_list.c10
10 files changed, 279 insertions, 119 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ba0f1ecb212..7c4e2713df0a 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -392,10 +392,9 @@ int disable_nonboot_cpus(void)
392 if (cpu == first_cpu) 392 if (cpu == first_cpu)
393 continue; 393 continue;
394 error = _cpu_down(cpu, 1); 394 error = _cpu_down(cpu, 1);
395 if (!error) { 395 if (!error)
396 cpumask_set_cpu(cpu, frozen_cpus); 396 cpumask_set_cpu(cpu, frozen_cpus);
397 printk("CPU%d is down\n", cpu); 397 else {
398 } else {
399 printk(KERN_ERR "Error taking CPU%d down: %d\n", 398 printk(KERN_ERR "Error taking CPU%d down: %d\n",
400 cpu, error); 399 cpu, error);
401 break; 400 break;
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 3e1c36e7998f..ede527708123 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1238,7 +1238,8 @@ hrtimer_interrupt_hanging(struct clock_event_device *dev,
1238 force_clock_reprogram = 1; 1238 force_clock_reprogram = 1;
1239 dev->min_delta_ns = (unsigned long)try_time.tv64 * 3; 1239 dev->min_delta_ns = (unsigned long)try_time.tv64 * 3;
1240 printk(KERN_WARNING "hrtimer: interrupt too slow, " 1240 printk(KERN_WARNING "hrtimer: interrupt too slow, "
1241 "forcing clock min delta to %lu ns\n", dev->min_delta_ns); 1241 "forcing clock min delta to %llu ns\n",
1242 (unsigned long long) dev->min_delta_ns);
1242} 1243}
1243/* 1244/*
1244 * High resolution timer interrupt 1245 * High resolution timer interrupt
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 5c9dc228747b..438ff4523513 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -384,7 +384,8 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
384 384
385/* 385/*
386 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer. 386 * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
387 * This is called from sys_timer_create with the new timer already locked. 387 * This is called from sys_timer_create() and do_cpu_nanosleep() with the
388 * new timer already all-zeros initialized.
388 */ 389 */
389int posix_cpu_timer_create(struct k_itimer *new_timer) 390int posix_cpu_timer_create(struct k_itimer *new_timer)
390{ 391{
@@ -396,8 +397,6 @@ int posix_cpu_timer_create(struct k_itimer *new_timer)
396 return -EINVAL; 397 return -EINVAL;
397 398
398 INIT_LIST_HEAD(&new_timer->it.cpu.entry); 399 INIT_LIST_HEAD(&new_timer->it.cpu.entry);
399 new_timer->it.cpu.incr.sched = 0;
400 new_timer->it.cpu.expires.sched = 0;
401 400
402 read_lock(&tasklist_lock); 401 read_lock(&tasklist_lock);
403 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) { 402 if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
diff --git a/kernel/time.c b/kernel/time.c
index 804798005d19..c6324d96009e 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -136,7 +136,6 @@ static inline void warp_clock(void)
136 write_seqlock_irq(&xtime_lock); 136 write_seqlock_irq(&xtime_lock);
137 wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60; 137 wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60;
138 xtime.tv_sec += sys_tz.tz_minuteswest * 60; 138 xtime.tv_sec += sys_tz.tz_minuteswest * 60;
139 update_xtime_cache(0);
140 write_sequnlock_irq(&xtime_lock); 139 write_sequnlock_irq(&xtime_lock);
141 clock_was_set(); 140 clock_was_set();
142} 141}
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 620b58abdc32..20a8920029ee 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -20,6 +20,8 @@
20#include <linux/sysdev.h> 20#include <linux/sysdev.h>
21#include <linux/tick.h> 21#include <linux/tick.h>
22 22
23#include "tick-internal.h"
24
23/* The registered clock event devices */ 25/* The registered clock event devices */
24static LIST_HEAD(clockevent_devices); 26static LIST_HEAD(clockevent_devices);
25static LIST_HEAD(clockevents_released); 27static LIST_HEAD(clockevents_released);
@@ -37,10 +39,9 @@ static DEFINE_SPINLOCK(clockevents_lock);
37 * 39 *
38 * Math helper, returns latch value converted to nanoseconds (bound checked) 40 * Math helper, returns latch value converted to nanoseconds (bound checked)
39 */ 41 */
40unsigned long clockevent_delta2ns(unsigned long latch, 42u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
41 struct clock_event_device *evt)
42{ 43{
43 u64 clc = ((u64) latch << evt->shift); 44 u64 clc = (u64) latch << evt->shift;
44 45
45 if (unlikely(!evt->mult)) { 46 if (unlikely(!evt->mult)) {
46 evt->mult = 1; 47 evt->mult = 1;
@@ -50,10 +51,10 @@ unsigned long clockevent_delta2ns(unsigned long latch,
50 do_div(clc, evt->mult); 51 do_div(clc, evt->mult);
51 if (clc < 1000) 52 if (clc < 1000)
52 clc = 1000; 53 clc = 1000;
53 if (clc > LONG_MAX) 54 if (clc > KTIME_MAX)
54 clc = LONG_MAX; 55 clc = KTIME_MAX;
55 56
56 return (unsigned long) clc; 57 return clc;
57} 58}
58EXPORT_SYMBOL_GPL(clockevent_delta2ns); 59EXPORT_SYMBOL_GPL(clockevent_delta2ns);
59 60
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 4a310906b3e8..d422c7b2236b 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -107,6 +107,59 @@ u64 timecounter_cyc2time(struct timecounter *tc,
107} 107}
108EXPORT_SYMBOL_GPL(timecounter_cyc2time); 108EXPORT_SYMBOL_GPL(timecounter_cyc2time);
109 109
110/**
111 * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
112 * @mult: pointer to mult variable
113 * @shift: pointer to shift variable
114 * @from: frequency to convert from
115 * @to: frequency to convert to
116 * @minsec: guaranteed runtime conversion range in seconds
117 *
118 * The function evaluates the shift/mult pair for the scaled math
119 * operations of clocksources and clockevents.
120 *
121 * @to and @from are frequency values in HZ. For clock sources @to is
122 * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
123 * event @to is the counter frequency and @from is NSEC_PER_SEC.
124 *
125 * The @minsec conversion range argument controls the time frame in
126 * seconds which must be covered by the runtime conversion with the
127 * calculated mult and shift factors. This guarantees that no 64bit
128 * overflow happens when the input value of the conversion is
129 * multiplied with the calculated mult factor. Larger ranges may
130 * reduce the conversion accuracy by chosing smaller mult and shift
131 * factors.
132 */
133void
134clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
135{
136 u64 tmp;
137 u32 sft, sftacc= 32;
138
139 /*
140 * Calculate the shift factor which is limiting the conversion
141 * range:
142 */
143 tmp = ((u64)minsec * from) >> 32;
144 while (tmp) {
145 tmp >>=1;
146 sftacc--;
147 }
148
149 /*
150 * Find the conversion shift/mult pair which has the best
151 * accuracy and fits the maxsec conversion range:
152 */
153 for (sft = 32; sft > 0; sft--) {
154 tmp = (u64) to << sft;
155 do_div(tmp, from);
156 if ((tmp >> sftacc) == 0)
157 break;
158 }
159 *mult = tmp;
160 *shift = sft;
161}
162
110/*[Clocksource internal variables]--------- 163/*[Clocksource internal variables]---------
111 * curr_clocksource: 164 * curr_clocksource:
112 * currently selected clocksource. 165 * currently selected clocksource.
@@ -413,6 +466,47 @@ void clocksource_touch_watchdog(void)
413 clocksource_resume_watchdog(); 466 clocksource_resume_watchdog();
414} 467}
415 468
469/**
470 * clocksource_max_deferment - Returns max time the clocksource can be deferred
471 * @cs: Pointer to clocksource
472 *
473 */
474static u64 clocksource_max_deferment(struct clocksource *cs)
475{
476 u64 max_nsecs, max_cycles;
477
478 /*
479 * Calculate the maximum number of cycles that we can pass to the
480 * cyc2ns function without overflowing a 64-bit signed result. The
481 * maximum number of cycles is equal to ULLONG_MAX/cs->mult which
482 * is equivalent to the below.
483 * max_cycles < (2^63)/cs->mult
484 * max_cycles < 2^(log2((2^63)/cs->mult))
485 * max_cycles < 2^(log2(2^63) - log2(cs->mult))
486 * max_cycles < 2^(63 - log2(cs->mult))
487 * max_cycles < 1 << (63 - log2(cs->mult))
488 * Please note that we add 1 to the result of the log2 to account for
489 * any rounding errors, ensure the above inequality is satisfied and
490 * no overflow will occur.
491 */
492 max_cycles = 1ULL << (63 - (ilog2(cs->mult) + 1));
493
494 /*
495 * The actual maximum number of cycles we can defer the clocksource is
496 * determined by the minimum of max_cycles and cs->mask.
497 */
498 max_cycles = min_t(u64, max_cycles, (u64) cs->mask);
499 max_nsecs = clocksource_cyc2ns(max_cycles, cs->mult, cs->shift);
500
501 /*
502 * To ensure that the clocksource does not wrap whilst we are idle,
503 * limit the time the clocksource can be deferred by 12.5%. Please
504 * note a margin of 12.5% is used because this can be computed with
505 * a shift, versus say 10% which would require division.
506 */
507 return max_nsecs - (max_nsecs >> 5);
508}
509
416#ifdef CONFIG_GENERIC_TIME 510#ifdef CONFIG_GENERIC_TIME
417 511
418/** 512/**
@@ -511,6 +605,9 @@ static void clocksource_enqueue(struct clocksource *cs)
511 */ 605 */
512int clocksource_register(struct clocksource *cs) 606int clocksource_register(struct clocksource *cs)
513{ 607{
608 /* calculate max idle time permitted for this clocksource */
609 cs->max_idle_ns = clocksource_max_deferment(cs);
610
514 mutex_lock(&clocksource_mutex); 611 mutex_lock(&clocksource_mutex);
515 clocksource_enqueue(cs); 612 clocksource_enqueue(cs);
516 clocksource_select(); 613 clocksource_select();
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index a96c0e2b89cf..0a8a213016f0 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -50,9 +50,9 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
50 dev->min_delta_ns += dev->min_delta_ns >> 1; 50 dev->min_delta_ns += dev->min_delta_ns >> 1;
51 51
52 printk(KERN_WARNING 52 printk(KERN_WARNING
53 "CE: %s increasing min_delta_ns to %lu nsec\n", 53 "CE: %s increasing min_delta_ns to %llu nsec\n",
54 dev->name ? dev->name : "?", 54 dev->name ? dev->name : "?",
55 dev->min_delta_ns << 1); 55 (unsigned long long) dev->min_delta_ns << 1);
56 56
57 i = 0; 57 i = 0;
58 } 58 }
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 89aed5933ed4..f992762d7f51 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -134,18 +134,13 @@ __setup("nohz=", setup_tick_nohz);
134 * value. We do this unconditionally on any cpu, as we don't know whether the 134 * value. We do this unconditionally on any cpu, as we don't know whether the
135 * cpu, which has the update task assigned is in a long sleep. 135 * cpu, which has the update task assigned is in a long sleep.
136 */ 136 */
137static void tick_nohz_update_jiffies(void) 137static void tick_nohz_update_jiffies(ktime_t now)
138{ 138{
139 int cpu = smp_processor_id(); 139 int cpu = smp_processor_id();
140 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); 140 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
141 unsigned long flags; 141 unsigned long flags;
142 ktime_t now;
143
144 if (!ts->tick_stopped)
145 return;
146 142
147 cpumask_clear_cpu(cpu, nohz_cpu_mask); 143 cpumask_clear_cpu(cpu, nohz_cpu_mask);
148 now = ktime_get();
149 ts->idle_waketime = now; 144 ts->idle_waketime = now;
150 145
151 local_irq_save(flags); 146 local_irq_save(flags);
@@ -155,20 +150,17 @@ static void tick_nohz_update_jiffies(void)
155 touch_softlockup_watchdog(); 150 touch_softlockup_watchdog();
156} 151}
157 152
158static void tick_nohz_stop_idle(int cpu) 153static void tick_nohz_stop_idle(int cpu, ktime_t now)
159{ 154{
160 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); 155 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
156 ktime_t delta;
161 157
162 if (ts->idle_active) { 158 delta = ktime_sub(now, ts->idle_entrytime);
163 ktime_t now, delta; 159 ts->idle_lastupdate = now;
164 now = ktime_get(); 160 ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
165 delta = ktime_sub(now, ts->idle_entrytime); 161 ts->idle_active = 0;
166 ts->idle_lastupdate = now;
167 ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
168 ts->idle_active = 0;
169 162
170 sched_clock_idle_wakeup_event(0); 163 sched_clock_idle_wakeup_event(0);
171 }
172} 164}
173 165
174static ktime_t tick_nohz_start_idle(struct tick_sched *ts) 166static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
@@ -216,6 +208,7 @@ void tick_nohz_stop_sched_tick(int inidle)
216 struct tick_sched *ts; 208 struct tick_sched *ts;
217 ktime_t last_update, expires, now; 209 ktime_t last_update, expires, now;
218 struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev; 210 struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
211 u64 time_delta;
219 int cpu; 212 int cpu;
220 213
221 local_irq_save(flags); 214 local_irq_save(flags);
@@ -263,7 +256,7 @@ void tick_nohz_stop_sched_tick(int inidle)
263 256
264 if (ratelimit < 10) { 257 if (ratelimit < 10) {
265 printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n", 258 printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
266 local_softirq_pending()); 259 (unsigned int) local_softirq_pending());
267 ratelimit++; 260 ratelimit++;
268 } 261 }
269 goto end; 262 goto end;
@@ -275,14 +268,18 @@ void tick_nohz_stop_sched_tick(int inidle)
275 seq = read_seqbegin(&xtime_lock); 268 seq = read_seqbegin(&xtime_lock);
276 last_update = last_jiffies_update; 269 last_update = last_jiffies_update;
277 last_jiffies = jiffies; 270 last_jiffies = jiffies;
271 time_delta = timekeeping_max_deferment();
278 } while (read_seqretry(&xtime_lock, seq)); 272 } while (read_seqretry(&xtime_lock, seq));
279 273
280 /* Get the next timer wheel timer */ 274 if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
281 next_jiffies = get_next_timer_interrupt(last_jiffies); 275 arch_needs_cpu(cpu)) {
282 delta_jiffies = next_jiffies - last_jiffies; 276 next_jiffies = last_jiffies + 1;
283
284 if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu))
285 delta_jiffies = 1; 277 delta_jiffies = 1;
278 } else {
279 /* Get the next timer wheel timer */
280 next_jiffies = get_next_timer_interrupt(last_jiffies);
281 delta_jiffies = next_jiffies - last_jiffies;
282 }
286 /* 283 /*
287 * Do not stop the tick, if we are only one off 284 * Do not stop the tick, if we are only one off
288 * or if the cpu is required for rcu 285 * or if the cpu is required for rcu
@@ -294,22 +291,51 @@ void tick_nohz_stop_sched_tick(int inidle)
294 if ((long)delta_jiffies >= 1) { 291 if ((long)delta_jiffies >= 1) {
295 292
296 /* 293 /*
297 * calculate the expiry time for the next timer wheel
298 * timer
299 */
300 expires = ktime_add_ns(last_update, tick_period.tv64 *
301 delta_jiffies);
302
303 /*
304 * If this cpu is the one which updates jiffies, then 294 * If this cpu is the one which updates jiffies, then
305 * give up the assignment and let it be taken by the 295 * give up the assignment and let it be taken by the
306 * cpu which runs the tick timer next, which might be 296 * cpu which runs the tick timer next, which might be
307 * this cpu as well. If we don't drop this here the 297 * this cpu as well. If we don't drop this here the
308 * jiffies might be stale and do_timer() never 298 * jiffies might be stale and do_timer() never
309 * invoked. 299 * invoked. Keep track of the fact that it was the one
300 * which had the do_timer() duty last. If this cpu is
301 * the one which had the do_timer() duty last, we
302 * limit the sleep time to the timekeeping
303 * max_deferement value which we retrieved
304 * above. Otherwise we can sleep as long as we want.
310 */ 305 */
311 if (cpu == tick_do_timer_cpu) 306 if (cpu == tick_do_timer_cpu) {
312 tick_do_timer_cpu = TICK_DO_TIMER_NONE; 307 tick_do_timer_cpu = TICK_DO_TIMER_NONE;
308 ts->do_timer_last = 1;
309 } else if (tick_do_timer_cpu != TICK_DO_TIMER_NONE) {
310 time_delta = KTIME_MAX;
311 ts->do_timer_last = 0;
312 } else if (!ts->do_timer_last) {
313 time_delta = KTIME_MAX;
314 }
315
316 /*
317 * calculate the expiry time for the next timer wheel
318 * timer. delta_jiffies >= NEXT_TIMER_MAX_DELTA signals
319 * that there is no timer pending or at least extremely
320 * far into the future (12 days for HZ=1000). In this
321 * case we set the expiry to the end of time.
322 */
323 if (likely(delta_jiffies < NEXT_TIMER_MAX_DELTA)) {
324 /*
325 * Calculate the time delta for the next timer event.
326 * If the time delta exceeds the maximum time delta
327 * permitted by the current clocksource then adjust
328 * the time delta accordingly to ensure the
329 * clocksource does not wrap.
330 */
331 time_delta = min_t(u64, time_delta,
332 tick_period.tv64 * delta_jiffies);
333 }
334
335 if (time_delta < KTIME_MAX)
336 expires = ktime_add_ns(last_update, time_delta);
337 else
338 expires.tv64 = KTIME_MAX;
313 339
314 if (delta_jiffies > 1) 340 if (delta_jiffies > 1)
315 cpumask_set_cpu(cpu, nohz_cpu_mask); 341 cpumask_set_cpu(cpu, nohz_cpu_mask);
@@ -342,22 +368,19 @@ void tick_nohz_stop_sched_tick(int inidle)
342 368
343 ts->idle_sleeps++; 369 ts->idle_sleeps++;
344 370
371 /* Mark expires */
372 ts->idle_expires = expires;
373
345 /* 374 /*
346 * delta_jiffies >= NEXT_TIMER_MAX_DELTA signals that 375 * If the expiration time == KTIME_MAX, then
347 * there is no timer pending or at least extremly far 376 * in this case we simply stop the tick timer.
348 * into the future (12 days for HZ=1000). In this case
349 * we simply stop the tick timer:
350 */ 377 */
351 if (unlikely(delta_jiffies >= NEXT_TIMER_MAX_DELTA)) { 378 if (unlikely(expires.tv64 == KTIME_MAX)) {
352 ts->idle_expires.tv64 = KTIME_MAX;
353 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) 379 if (ts->nohz_mode == NOHZ_MODE_HIGHRES)
354 hrtimer_cancel(&ts->sched_timer); 380 hrtimer_cancel(&ts->sched_timer);
355 goto out; 381 goto out;
356 } 382 }
357 383
358 /* Mark expiries */
359 ts->idle_expires = expires;
360
361 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) { 384 if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
362 hrtimer_start(&ts->sched_timer, expires, 385 hrtimer_start(&ts->sched_timer, expires,
363 HRTIMER_MODE_ABS_PINNED); 386 HRTIMER_MODE_ABS_PINNED);
@@ -436,7 +459,11 @@ void tick_nohz_restart_sched_tick(void)
436 ktime_t now; 459 ktime_t now;
437 460
438 local_irq_disable(); 461 local_irq_disable();
439 tick_nohz_stop_idle(cpu); 462 if (ts->idle_active || (ts->inidle && ts->tick_stopped))
463 now = ktime_get();
464
465 if (ts->idle_active)
466 tick_nohz_stop_idle(cpu, now);
440 467
441 if (!ts->inidle || !ts->tick_stopped) { 468 if (!ts->inidle || !ts->tick_stopped) {
442 ts->inidle = 0; 469 ts->inidle = 0;
@@ -450,7 +477,6 @@ void tick_nohz_restart_sched_tick(void)
450 477
451 /* Update jiffies first */ 478 /* Update jiffies first */
452 select_nohz_load_balancer(0); 479 select_nohz_load_balancer(0);
453 now = ktime_get();
454 tick_do_update_jiffies64(now); 480 tick_do_update_jiffies64(now);
455 cpumask_clear_cpu(cpu, nohz_cpu_mask); 481 cpumask_clear_cpu(cpu, nohz_cpu_mask);
456 482
@@ -584,22 +610,18 @@ static void tick_nohz_switch_to_nohz(void)
584 * timer and do not touch the other magic bits which need to be done 610 * timer and do not touch the other magic bits which need to be done
585 * when idle is left. 611 * when idle is left.
586 */ 612 */
587static void tick_nohz_kick_tick(int cpu) 613static void tick_nohz_kick_tick(int cpu, ktime_t now)
588{ 614{
589#if 0 615#if 0
590 /* Switch back to 2.6.27 behaviour */ 616 /* Switch back to 2.6.27 behaviour */
591 617
592 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); 618 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
593 ktime_t delta, now; 619 ktime_t delta;
594
595 if (!ts->tick_stopped)
596 return;
597 620
598 /* 621 /*
599 * Do not touch the tick device, when the next expiry is either 622 * Do not touch the tick device, when the next expiry is either
600 * already reached or less/equal than the tick period. 623 * already reached or less/equal than the tick period.
601 */ 624 */
602 now = ktime_get();
603 delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now); 625 delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);
604 if (delta.tv64 <= tick_period.tv64) 626 if (delta.tv64 <= tick_period.tv64)
605 return; 627 return;
@@ -608,9 +630,26 @@ static void tick_nohz_kick_tick(int cpu)
608#endif 630#endif
609} 631}
610 632
633static inline void tick_check_nohz(int cpu)
634{
635 struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
636 ktime_t now;
637
638 if (!ts->idle_active && !ts->tick_stopped)
639 return;
640 now = ktime_get();
641 if (ts->idle_active)
642 tick_nohz_stop_idle(cpu, now);
643 if (ts->tick_stopped) {
644 tick_nohz_update_jiffies(now);
645 tick_nohz_kick_tick(cpu, now);
646 }
647}
648
611#else 649#else
612 650
613static inline void tick_nohz_switch_to_nohz(void) { } 651static inline void tick_nohz_switch_to_nohz(void) { }
652static inline void tick_check_nohz(int cpu) { }
614 653
615#endif /* NO_HZ */ 654#endif /* NO_HZ */
616 655
@@ -620,11 +659,7 @@ static inline void tick_nohz_switch_to_nohz(void) { }
620void tick_check_idle(int cpu) 659void tick_check_idle(int cpu)
621{ 660{
622 tick_check_oneshot_broadcast(cpu); 661 tick_check_oneshot_broadcast(cpu);
623#ifdef CONFIG_NO_HZ 662 tick_check_nohz(cpu);
624 tick_nohz_stop_idle(cpu);
625 tick_nohz_update_jiffies();
626 tick_nohz_kick_tick(cpu);
627#endif
628} 663}
629 664
630/* 665/*
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index c3a4e2907eaa..d1aebd73b191 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -165,13 +165,6 @@ struct timespec raw_time;
165/* flag for if timekeeping is suspended */ 165/* flag for if timekeeping is suspended */
166int __read_mostly timekeeping_suspended; 166int __read_mostly timekeeping_suspended;
167 167
168static struct timespec xtime_cache __attribute__ ((aligned (16)));
169void update_xtime_cache(u64 nsec)
170{
171 xtime_cache = xtime;
172 timespec_add_ns(&xtime_cache, nsec);
173}
174
175/* must hold xtime_lock */ 168/* must hold xtime_lock */
176void timekeeping_leap_insert(int leapsecond) 169void timekeeping_leap_insert(int leapsecond)
177{ 170{
@@ -332,8 +325,6 @@ int do_settimeofday(struct timespec *tv)
332 325
333 xtime = *tv; 326 xtime = *tv;
334 327
335 update_xtime_cache(0);
336
337 timekeeper.ntp_error = 0; 328 timekeeper.ntp_error = 0;
338 ntp_clear(); 329 ntp_clear();
339 330
@@ -488,6 +479,17 @@ int timekeeping_valid_for_hres(void)
488} 479}
489 480
490/** 481/**
482 * timekeeping_max_deferment - Returns max time the clocksource can be deferred
483 *
484 * Caller must observe xtime_lock via read_seqbegin/read_seqretry to
485 * ensure that the clocksource does not change!
486 */
487u64 timekeeping_max_deferment(void)
488{
489 return timekeeper.clock->max_idle_ns;
490}
491
492/**
491 * read_persistent_clock - Return time from the persistent clock. 493 * read_persistent_clock - Return time from the persistent clock.
492 * 494 *
493 * Weak dummy function for arches that do not yet support it. 495 * Weak dummy function for arches that do not yet support it.
@@ -548,7 +550,6 @@ void __init timekeeping_init(void)
548 } 550 }
549 set_normalized_timespec(&wall_to_monotonic, 551 set_normalized_timespec(&wall_to_monotonic,
550 -boot.tv_sec, -boot.tv_nsec); 552 -boot.tv_sec, -boot.tv_nsec);
551 update_xtime_cache(0);
552 total_sleep_time.tv_sec = 0; 553 total_sleep_time.tv_sec = 0;
553 total_sleep_time.tv_nsec = 0; 554 total_sleep_time.tv_nsec = 0;
554 write_sequnlock_irqrestore(&xtime_lock, flags); 555 write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -582,7 +583,6 @@ static int timekeeping_resume(struct sys_device *dev)
582 wall_to_monotonic = timespec_sub(wall_to_monotonic, ts); 583 wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
583 total_sleep_time = timespec_add_safe(total_sleep_time, ts); 584 total_sleep_time = timespec_add_safe(total_sleep_time, ts);
584 } 585 }
585 update_xtime_cache(0);
586 /* re-base the last cycle value */ 586 /* re-base the last cycle value */
587 timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock); 587 timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
588 timekeeper.ntp_error = 0; 588 timekeeper.ntp_error = 0;
@@ -723,6 +723,49 @@ static void timekeeping_adjust(s64 offset)
723} 723}
724 724
725/** 725/**
726 * logarithmic_accumulation - shifted accumulation of cycles
727 *
728 * This functions accumulates a shifted interval of cycles into
729 * into a shifted interval nanoseconds. Allows for O(log) accumulation
730 * loop.
731 *
732 * Returns the unconsumed cycles.
733 */
734static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
735{
736 u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift;
737
738 /* If the offset is smaller then a shifted interval, do nothing */
739 if (offset < timekeeper.cycle_interval<<shift)
740 return offset;
741
742 /* Accumulate one shifted interval */
743 offset -= timekeeper.cycle_interval << shift;
744 timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift;
745
746 timekeeper.xtime_nsec += timekeeper.xtime_interval << shift;
747 while (timekeeper.xtime_nsec >= nsecps) {
748 timekeeper.xtime_nsec -= nsecps;
749 xtime.tv_sec++;
750 second_overflow();
751 }
752
753 /* Accumulate into raw time */
754 raw_time.tv_nsec += timekeeper.raw_interval << shift;;
755 while (raw_time.tv_nsec >= NSEC_PER_SEC) {
756 raw_time.tv_nsec -= NSEC_PER_SEC;
757 raw_time.tv_sec++;
758 }
759
760 /* Accumulate error between NTP and clock interval */
761 timekeeper.ntp_error += tick_length << shift;
762 timekeeper.ntp_error -= timekeeper.xtime_interval <<
763 (timekeeper.ntp_error_shift + shift);
764
765 return offset;
766}
767
768/**
726 * update_wall_time - Uses the current clocksource to increment the wall time 769 * update_wall_time - Uses the current clocksource to increment the wall time
727 * 770 *
728 * Called from the timer interrupt, must hold a write on xtime_lock. 771 * Called from the timer interrupt, must hold a write on xtime_lock.
@@ -731,7 +774,7 @@ void update_wall_time(void)
731{ 774{
732 struct clocksource *clock; 775 struct clocksource *clock;
733 cycle_t offset; 776 cycle_t offset;
734 u64 nsecs; 777 int shift = 0, maxshift;
735 778
736 /* Make sure we're fully resumed: */ 779 /* Make sure we're fully resumed: */
737 if (unlikely(timekeeping_suspended)) 780 if (unlikely(timekeeping_suspended))
@@ -745,33 +788,22 @@ void update_wall_time(void)
745#endif 788#endif
746 timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift; 789 timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift;
747 790
748 /* normally this loop will run just once, however in the 791 /*
749 * case of lost or late ticks, it will accumulate correctly. 792 * With NO_HZ we may have to accumulate many cycle_intervals
793 * (think "ticks") worth of time at once. To do this efficiently,
794 * we calculate the largest doubling multiple of cycle_intervals
795 * that is smaller then the offset. We then accumulate that
796 * chunk in one go, and then try to consume the next smaller
797 * doubled multiple.
750 */ 798 */
799 shift = ilog2(offset) - ilog2(timekeeper.cycle_interval);
800 shift = max(0, shift);
801 /* Bound shift to one less then what overflows tick_length */
802 maxshift = (8*sizeof(tick_length) - (ilog2(tick_length)+1)) - 1;
803 shift = min(shift, maxshift);
751 while (offset >= timekeeper.cycle_interval) { 804 while (offset >= timekeeper.cycle_interval) {
752 u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift; 805 offset = logarithmic_accumulation(offset, shift);
753 806 shift--;
754 /* accumulate one interval */
755 offset -= timekeeper.cycle_interval;
756 clock->cycle_last += timekeeper.cycle_interval;
757
758 timekeeper.xtime_nsec += timekeeper.xtime_interval;
759 if (timekeeper.xtime_nsec >= nsecps) {
760 timekeeper.xtime_nsec -= nsecps;
761 xtime.tv_sec++;
762 second_overflow();
763 }
764
765 raw_time.tv_nsec += timekeeper.raw_interval;
766 if (raw_time.tv_nsec >= NSEC_PER_SEC) {
767 raw_time.tv_nsec -= NSEC_PER_SEC;
768 raw_time.tv_sec++;
769 }
770
771 /* accumulate error between NTP and clock interval */
772 timekeeper.ntp_error += tick_length;
773 timekeeper.ntp_error -= timekeeper.xtime_interval <<
774 timekeeper.ntp_error_shift;
775 } 807 }
776 808
777 /* correct the clock when NTP error is too big */ 809 /* correct the clock when NTP error is too big */
@@ -807,9 +839,6 @@ void update_wall_time(void)
807 timekeeper.ntp_error += timekeeper.xtime_nsec << 839 timekeeper.ntp_error += timekeeper.xtime_nsec <<
808 timekeeper.ntp_error_shift; 840 timekeeper.ntp_error_shift;
809 841
810 nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
811 update_xtime_cache(nsecs);
812
813 /* check to see if there is a new clocksource to use */ 842 /* check to see if there is a new clocksource to use */
814 update_vsyscall(&xtime, timekeeper.clock); 843 update_vsyscall(&xtime, timekeeper.clock);
815} 844}
@@ -846,13 +875,13 @@ void monotonic_to_bootbased(struct timespec *ts)
846 875
847unsigned long get_seconds(void) 876unsigned long get_seconds(void)
848{ 877{
849 return xtime_cache.tv_sec; 878 return xtime.tv_sec;
850} 879}
851EXPORT_SYMBOL(get_seconds); 880EXPORT_SYMBOL(get_seconds);
852 881
853struct timespec __current_kernel_time(void) 882struct timespec __current_kernel_time(void)
854{ 883{
855 return xtime_cache; 884 return xtime;
856} 885}
857 886
858struct timespec current_kernel_time(void) 887struct timespec current_kernel_time(void)
@@ -862,8 +891,7 @@ struct timespec current_kernel_time(void)
862 891
863 do { 892 do {
864 seq = read_seqbegin(&xtime_lock); 893 seq = read_seqbegin(&xtime_lock);
865 894 now = xtime;
866 now = xtime_cache;
867 } while (read_seqretry(&xtime_lock, seq)); 895 } while (read_seqretry(&xtime_lock, seq));
868 896
869 return now; 897 return now;
@@ -877,8 +905,7 @@ struct timespec get_monotonic_coarse(void)
877 905
878 do { 906 do {
879 seq = read_seqbegin(&xtime_lock); 907 seq = read_seqbegin(&xtime_lock);
880 908 now = xtime;
881 now = xtime_cache;
882 mono = wall_to_monotonic; 909 mono = wall_to_monotonic;
883 } while (read_seqretry(&xtime_lock, seq)); 910 } while (read_seqretry(&xtime_lock, seq));
884 911
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 1b5b7aa2fdfd..665c76edbf17 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -204,10 +204,12 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
204 return; 204 return;
205 } 205 }
206 SEQ_printf(m, "%s\n", dev->name); 206 SEQ_printf(m, "%s\n", dev->name);
207 SEQ_printf(m, " max_delta_ns: %lu\n", dev->max_delta_ns); 207 SEQ_printf(m, " max_delta_ns: %llu\n",
208 SEQ_printf(m, " min_delta_ns: %lu\n", dev->min_delta_ns); 208 (unsigned long long) dev->max_delta_ns);
209 SEQ_printf(m, " mult: %lu\n", dev->mult); 209 SEQ_printf(m, " min_delta_ns: %llu\n",
210 SEQ_printf(m, " shift: %d\n", dev->shift); 210 (unsigned long long) dev->min_delta_ns);
211 SEQ_printf(m, " mult: %u\n", dev->mult);
212 SEQ_printf(m, " shift: %u\n", dev->shift);
211 SEQ_printf(m, " mode: %d\n", dev->mode); 213 SEQ_printf(m, " mode: %d\n", dev->mode);
212 SEQ_printf(m, " next_event: %Ld nsecs\n", 214 SEQ_printf(m, " next_event: %Ld nsecs\n",
213 (unsigned long long) ktime_to_ns(dev->next_event)); 215 (unsigned long long) ktime_to_ns(dev->next_event));
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-20 11:47:59 -0500