projects/linux·blob v2.6.19-rc1 · refs

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1/*
2 * linux/kernel/hrtimer.c
3 *
4 * Copyright(C) 2005, Thomas Gleixner <[email protected]>
5 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
6 *
7 * High-resolution kernel timers
8 *
9 * In contrast to the low-resolution timeout API implemented in
10 * kernel/timer.c, hrtimers provide finer resolution and accuracy
11 * depending on system configuration and capabilities.
12 *
13 * These timers are currently used for:
14 * - itimers
15 * - POSIX timers
16 * - nanosleep
17 * - precise in-kernel timing
18 *
19 * Started by: Thomas Gleixner and Ingo Molnar
20 *
21 * Credits:
22 * based on kernel/timer.c
23 *
24 * Help, testing, suggestions, bugfixes, improvements were
25 * provided by:
26 *
27 * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
28 * et. al.
29 *
30 * For licencing details see kernel-base/COPYING
31 */
32
33#include <linux/cpu.h>
34#include <linux/module.h>
35#include <linux/percpu.h>
36#include <linux/hrtimer.h>
37#include <linux/notifier.h>
38#include <linux/syscalls.h>
39#include <linux/interrupt.h>
40
41#include <asm/uaccess.h>
42
43/**
44 * ktime_get - get the monotonic time in ktime_t format
45 *
46 * returns the time in ktime_t format
47 */
48static ktime_t ktime_get(void)
49{
50 struct timespec now;
51
52 ktime_get_ts(&now);
53
54 return timespec_to_ktime(now);
55}
56
57/**
58 * ktime_get_real - get the real (wall-) time in ktime_t format
59 *
60 * returns the time in ktime_t format
61 */
62static ktime_t ktime_get_real(void)
63{
64 struct timespec now;
65
66 getnstimeofday(&now);
67
68 return timespec_to_ktime(now);
69}
70
71EXPORT_SYMBOL_GPL(ktime_get_real);
72
73/*
74 * The timer bases:
75 *
76 * Note: If we want to add new timer bases, we have to skip the two
77 * clock ids captured by the cpu-timers. We do this by holding empty
78 * entries rather than doing math adjustment of the clock ids.
79 * This ensures that we capture erroneous accesses to these clock ids
80 * rather than moving them into the range of valid clock id's.
81 */
82
83#define MAX_HRTIMER_BASES 2
84
85static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) =
86{
87 {
88 .index = CLOCK_REALTIME,
89 .get_time = &ktime_get_real,
90 .resolution = KTIME_REALTIME_RES,
91 },
92 {
93 .index = CLOCK_MONOTONIC,
94 .get_time = &ktime_get,
95 .resolution = KTIME_MONOTONIC_RES,
96 },
97};
98
99/**
100 * ktime_get_ts - get the monotonic clock in timespec format
101 * @ts: pointer to timespec variable
102 *
103 * The function calculates the monotonic clock from the realtime
104 * clock and the wall_to_monotonic offset and stores the result
105 * in normalized timespec format in the variable pointed to by ts.
106 */
107void ktime_get_ts(struct timespec *ts)
108{
109 struct timespec tomono;
110 unsigned long seq;
111
112 do {
113 seq = read_seqbegin(&xtime_lock);
114 getnstimeofday(ts);
115 tomono = wall_to_monotonic;
116
117 } while (read_seqretry(&xtime_lock, seq));
118
119 set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
120 ts->tv_nsec + tomono.tv_nsec);
121}
122EXPORT_SYMBOL_GPL(ktime_get_ts);
123
124/*
125 * Get the coarse grained time at the softirq based on xtime and
126 * wall_to_monotonic.
127 */
128static void hrtimer_get_softirq_time(struct hrtimer_base *base)
129{
130 ktime_t xtim, tomono;
131 unsigned long seq;
132
133 do {
134 seq = read_seqbegin(&xtime_lock);
135 xtim = timespec_to_ktime(xtime);
136 tomono = timespec_to_ktime(wall_to_monotonic);
137
138 } while (read_seqretry(&xtime_lock, seq));
139
140 base[CLOCK_REALTIME].softirq_time = xtim;
141 base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono);
142}
143
144/*
145 * Functions and macros which are different for UP/SMP systems are kept in a
146 * single place
147 */
148#ifdef CONFIG_SMP
149
150#define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0)
151
152/*
153 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
154 * means that all timers which are tied to this base via timer->base are
155 * locked, and the base itself is locked too.
156 *
157 * So __run_timers/migrate_timers can safely modify all timers which could
158 * be found on the lists/queues.
159 *
160 * When the timer's base is locked, and the timer removed from list, it is
161 * possible to set timer->base = NULL and drop the lock: the timer remains
162 * locked.
163 */
164static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer,
165 unsigned long *flags)
166{
167 struct hrtimer_base *base;
168
169 for (;;) {
170 base = timer->base;
171 if (likely(base != NULL)) {
172 spin_lock_irqsave(&base->lock, *flags);
173 if (likely(base == timer->base))
174 return base;
175 /* The timer has migrated to another CPU: */
176 spin_unlock_irqrestore(&base->lock, *flags);
177 }
178 cpu_relax();
179 }
180}
181
182/*
183 * Switch the timer base to the current CPU when possible.
184 */
185static inline struct hrtimer_base *
186switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base)
187{
188 struct hrtimer_base *new_base;
189
190 new_base = &__get_cpu_var(hrtimer_bases)[base->index];
191
192 if (base != new_base) {
193 /*
194 * We are trying to schedule the timer on the local CPU.
195 * However we can't change timer's base while it is running,
196 * so we keep it on the same CPU. No hassle vs. reprogramming
197 * the event source in the high resolution case. The softirq
198 * code will take care of this when the timer function has
199 * completed. There is no conflict as we hold the lock until
200 * the timer is enqueued.
201 */
202 if (unlikely(base->curr_timer == timer))
203 return base;
204
205 /* See the comment in lock_timer_base() */
206 timer->base = NULL;
207 spin_unlock(&base->lock);
208 spin_lock(&new_base->lock);
209 timer->base = new_base;
210 }
211 return new_base;
212}
213
214#else /* CONFIG_SMP */
215
216#define set_curr_timer(b, t) do { } while (0)
217
218static inline struct hrtimer_base *
219lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
220{
221 struct hrtimer_base *base = timer->base;
222
223 spin_lock_irqsave(&base->lock, *flags);
224
225 return base;
226}
227
228#define switch_hrtimer_base(t, b) (b)
229
230#endif /* !CONFIG_SMP */
231
232/*
233 * Functions for the union type storage format of ktime_t which are
234 * too large for inlining:
235 */
236#if BITS_PER_LONG < 64
237# ifndef CONFIG_KTIME_SCALAR
238/**
239 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
240 * @kt: addend
241 * @nsec: the scalar nsec value to add
242 *
243 * Returns the sum of kt and nsec in ktime_t format
244 */
245ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
246{
247 ktime_t tmp;
248
249 if (likely(nsec < NSEC_PER_SEC)) {
250 tmp.tv64 = nsec;
251 } else {
252 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
253
254 tmp = ktime_set((long)nsec, rem);
255 }
256
257 return ktime_add(kt, tmp);
258}
259
260#else /* CONFIG_KTIME_SCALAR */
261
262# endif /* !CONFIG_KTIME_SCALAR */
263
264/*
265 * Divide a ktime value by a nanosecond value
266 */
267static unsigned long ktime_divns(const ktime_t kt, s64 div)
268{
269 u64 dclc, inc, dns;
270 int sft = 0;
271
272 dclc = dns = ktime_to_ns(kt);
273 inc = div;
274 /* Make sure the divisor is less than 2^32: */
275 while (div >> 32) {
276 sft++;
277 div >>= 1;
278 }
279 dclc >>= sft;
280 do_div(dclc, (unsigned long) div);
281
282 return (unsigned long) dclc;
283}
284
285#else /* BITS_PER_LONG < 64 */
286# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
287#endif /* BITS_PER_LONG >= 64 */
288
289/*
290 * Counterpart to lock_timer_base above:
291 */
292static inline
293void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
294{
295 spin_unlock_irqrestore(&timer->base->lock, *flags);
296}
297
298/**
299 * hrtimer_forward - forward the timer expiry
300 * @timer: hrtimer to forward
301 * @now: forward past this time
302 * @interval: the interval to forward
303 *
304 * Forward the timer expiry so it will expire in the future.
305 * Returns the number of overruns.
306 */
307unsigned long
308hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
309{
310 unsigned long orun = 1;
311 ktime_t delta;
312
313 delta = ktime_sub(now, timer->expires);
314
315 if (delta.tv64 < 0)
316 return 0;
317
318 if (interval.tv64 < timer->base->resolution.tv64)
319 interval.tv64 = timer->base->resolution.tv64;
320
321 if (unlikely(delta.tv64 >= interval.tv64)) {
322 s64 incr = ktime_to_ns(interval);
323
324 orun = ktime_divns(delta, incr);
325 timer->expires = ktime_add_ns(timer->expires, incr * orun);
326 if (timer->expires.tv64 > now.tv64)
327 return orun;
328 /*
329 * This (and the ktime_add() below) is the
330 * correction for exact:
331 */
332 orun++;
333 }
334 timer->expires = ktime_add(timer->expires, interval);
335
336 return orun;
337}
338
339/*
340 * enqueue_hrtimer - internal function to (re)start a timer
341 *
342 * The timer is inserted in expiry order. Insertion into the
343 * red black tree is O(log(n)). Must hold the base lock.
344 */
345static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
346{
347 struct rb_node **link = &base->active.rb_node;
348 struct rb_node *parent = NULL;
349 struct hrtimer *entry;
350
351 /*
352 * Find the right place in the rbtree:
353 */
354 while (*link) {
355 parent = *link;
356 entry = rb_entry(parent, struct hrtimer, node);
357 /*
358 * We dont care about collisions. Nodes with
359 * the same expiry time stay together.
360 */
361 if (timer->expires.tv64 < entry->expires.tv64)
362 link = &(*link)->rb_left;
363 else
364 link = &(*link)->rb_right;
365 }
366
367 /*
368 * Insert the timer to the rbtree and check whether it
369 * replaces the first pending timer
370 */
371 rb_link_node(&timer->node, parent, link);
372 rb_insert_color(&timer->node, &base->active);
373
374 if (!base->first || timer->expires.tv64 <
375 rb_entry(base->first, struct hrtimer, node)->expires.tv64)
376 base->first = &timer->node;
377}
378
379/*
380 * __remove_hrtimer - internal function to remove a timer
381 *
382 * Caller must hold the base lock.
383 */
384static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
385{
386 /*
387 * Remove the timer from the rbtree and replace the
388 * first entry pointer if necessary.
389 */
390 if (base->first == &timer->node)
391 base->first = rb_next(&timer->node);
392 rb_erase(&timer->node, &base->active);
393 rb_set_parent(&timer->node, &timer->node);
394}
395
396/*
397 * remove hrtimer, called with base lock held
398 */
399static inline int
400remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
401{
402 if (hrtimer_active(timer)) {
403 __remove_hrtimer(timer, base);
404 return 1;
405 }
406 return 0;
407}
408
409/**
410 * hrtimer_start - (re)start an relative timer on the current CPU
411 * @timer: the timer to be added
412 * @tim: expiry time
413 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
414 *
415 * Returns:
416 * 0 on success
417 * 1 when the timer was active
418 */
419int
420hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
421{
422 struct hrtimer_base *base, *new_base;
423 unsigned long flags;
424 int ret;
425
426 base = lock_hrtimer_base(timer, &flags);
427
428 /* Remove an active timer from the queue: */
429 ret = remove_hrtimer(timer, base);
430
431 /* Switch the timer base, if necessary: */
432 new_base = switch_hrtimer_base(timer, base);
433
434 if (mode == HRTIMER_REL) {
435 tim = ktime_add(tim, new_base->get_time());
436 /*
437 * CONFIG_TIME_LOW_RES is a temporary way for architectures
438 * to signal that they simply return xtime in
439 * do_gettimeoffset(). In this case we want to round up by
440 * resolution when starting a relative timer, to avoid short
441 * timeouts. This will go away with the GTOD framework.
442 */
443#ifdef CONFIG_TIME_LOW_RES
444 tim = ktime_add(tim, base->resolution);
445#endif
446 }
447 timer->expires = tim;
448
449 enqueue_hrtimer(timer, new_base);
450
451 unlock_hrtimer_base(timer, &flags);
452
453 return ret;
454}
455EXPORT_SYMBOL_GPL(hrtimer_start);
456
457/**
458 * hrtimer_try_to_cancel - try to deactivate a timer
459 * @timer: hrtimer to stop
460 *
461 * Returns:
462 * 0 when the timer was not active
463 * 1 when the timer was active
464 * -1 when the timer is currently excuting the callback function and
465 * cannot be stopped
466 */
467int hrtimer_try_to_cancel(struct hrtimer *timer)
468{
469 struct hrtimer_base *base;
470 unsigned long flags;
471 int ret = -1;
472
473 base = lock_hrtimer_base(timer, &flags);
474
475 if (base->curr_timer != timer)
476 ret = remove_hrtimer(timer, base);
477
478 unlock_hrtimer_base(timer, &flags);
479
480 return ret;
481
482}
483EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
484
485/**
486 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
487 * @timer: the timer to be cancelled
488 *
489 * Returns:
490 * 0 when the timer was not active
491 * 1 when the timer was active
492 */
493int hrtimer_cancel(struct hrtimer *timer)
494{
495 for (;;) {
496 int ret = hrtimer_try_to_cancel(timer);
497
498 if (ret >= 0)
499 return ret;
500 cpu_relax();
501 }
502}
503EXPORT_SYMBOL_GPL(hrtimer_cancel);
504
505/**
506 * hrtimer_get_remaining - get remaining time for the timer
507 * @timer: the timer to read
508 */
509ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
510{
511 struct hrtimer_base *base;
512 unsigned long flags;
513 ktime_t rem;
514
515 base = lock_hrtimer_base(timer, &flags);
516 rem = ktime_sub(timer->expires, timer->base->get_time());
517 unlock_hrtimer_base(timer, &flags);
518
519 return rem;
520}
521EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
522
523#ifdef CONFIG_NO_IDLE_HZ
524/**
525 * hrtimer_get_next_event - get the time until next expiry event
526 *
527 * Returns the delta to the next expiry event or KTIME_MAX if no timer
528 * is pending.
529 */
530ktime_t hrtimer_get_next_event(void)
531{
532 struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
533 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
534 unsigned long flags;
535 int i;
536
537 for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
538 struct hrtimer *timer;
539
540 spin_lock_irqsave(&base->lock, flags);
541 if (!base->first) {
542 spin_unlock_irqrestore(&base->lock, flags);
543 continue;
544 }
545 timer = rb_entry(base->first, struct hrtimer, node);
546 delta.tv64 = timer->expires.tv64;
547 spin_unlock_irqrestore(&base->lock, flags);
548 delta = ktime_sub(delta, base->get_time());
549 if (delta.tv64 < mindelta.tv64)
550 mindelta.tv64 = delta.tv64;
551 }
552 if (mindelta.tv64 < 0)
553 mindelta.tv64 = 0;
554 return mindelta;
555}
556#endif
557
558/**
559 * hrtimer_init - initialize a timer to the given clock
560 * @timer: the timer to be initialized
561 * @clock_id: the clock to be used
562 * @mode: timer mode abs/rel
563 */
564void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
565 enum hrtimer_mode mode)
566{
567 struct hrtimer_base *bases;
568
569 memset(timer, 0, sizeof(struct hrtimer));
570
571 bases = __raw_get_cpu_var(hrtimer_bases);
572
573 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS)
574 clock_id = CLOCK_MONOTONIC;
575
576 timer->base = &bases[clock_id];
577 rb_set_parent(&timer->node, &timer->node);
578}
579EXPORT_SYMBOL_GPL(hrtimer_init);
580
581/**
582 * hrtimer_get_res - get the timer resolution for a clock
583 * @which_clock: which clock to query
584 * @tp: pointer to timespec variable to store the resolution
585 *
586 * Store the resolution of the clock selected by which_clock in the
587 * variable pointed to by tp.
588 */
589int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
590{
591 struct hrtimer_base *bases;
592
593 bases = __raw_get_cpu_var(hrtimer_bases);
594 *tp = ktime_to_timespec(bases[which_clock].resolution);
595
596 return 0;
597}
598EXPORT_SYMBOL_GPL(hrtimer_get_res);
599
600/*
601 * Expire the per base hrtimer-queue:
602 */
603static inline void run_hrtimer_queue(struct hrtimer_base *base)
604{
605 struct rb_node *node;
606
607 if (!base->first)
608 return;
609
610 if (base->get_softirq_time)
611 base->softirq_time = base->get_softirq_time();
612
613 spin_lock_irq(&base->lock);
614
615 while ((node = base->first)) {
616 struct hrtimer *timer;
617 int (*fn)(struct hrtimer *);
618 int restart;
619
620 timer = rb_entry(node, struct hrtimer, node);
621 if (base->softirq_time.tv64 <= timer->expires.tv64)
622 break;
623
624 fn = timer->function;
625 set_curr_timer(base, timer);
626 __remove_hrtimer(timer, base);
627 spin_unlock_irq(&base->lock);
628
629 restart = fn(timer);
630
631 spin_lock_irq(&base->lock);
632
633 if (restart != HRTIMER_NORESTART) {
634 BUG_ON(hrtimer_active(timer));
635 enqueue_hrtimer(timer, base);
636 }
637 }
638 set_curr_timer(base, NULL);
639 spin_unlock_irq(&base->lock);
640}
641
642/*
643 * Called from timer softirq every jiffy, expire hrtimers:
644 */
645void hrtimer_run_queues(void)
646{
647 struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
648 int i;
649
650 hrtimer_get_softirq_time(base);
651
652 for (i = 0; i < MAX_HRTIMER_BASES; i++)
653 run_hrtimer_queue(&base[i]);
654}
655
656/*
657 * Sleep related functions:
658 */
659static int hrtimer_wakeup(struct hrtimer *timer)
660{
661 struct hrtimer_sleeper *t =
662 container_of(timer, struct hrtimer_sleeper, timer);
663 struct task_struct *task = t->task;
664
665 t->task = NULL;
666 if (task)
667 wake_up_process(task);
668
669 return HRTIMER_NORESTART;
670}
671
672void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
673{
674 sl->timer.function = hrtimer_wakeup;
675 sl->task = task;
676}
677
678static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
679{
680 hrtimer_init_sleeper(t, current);
681
682 do {
683 set_current_state(TASK_INTERRUPTIBLE);
684 hrtimer_start(&t->timer, t->timer.expires, mode);
685
686 schedule();
687
688 hrtimer_cancel(&t->timer);
689 mode = HRTIMER_ABS;
690
691 } while (t->task && !signal_pending(current));
692
693 return t->task == NULL;
694}
695
696long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
697{
698 struct hrtimer_sleeper t;
699 struct timespec __user *rmtp;
700 struct timespec tu;
701 ktime_t time;
702
703 restart->fn = do_no_restart_syscall;
704
705 hrtimer_init(&t.timer, restart->arg0, HRTIMER_ABS);
706 t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;
707
708 if (do_nanosleep(&t, HRTIMER_ABS))
709 return 0;
710
711 rmtp = (struct timespec __user *) restart->arg1;
712 if (rmtp) {
713 time = ktime_sub(t.timer.expires, t.timer.base->get_time());
714 if (time.tv64 <= 0)
715 return 0;
716 tu = ktime_to_timespec(time);
717 if (copy_to_user(rmtp, &tu, sizeof(tu)))
718 return -EFAULT;
719 }
720
721 restart->fn = hrtimer_nanosleep_restart;
722
723 /* The other values in restart are already filled in */
724 return -ERESTART_RESTARTBLOCK;
725}
726
727long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
728 const enum hrtimer_mode mode, const clockid_t clockid)
729{
730 struct restart_block *restart;
731 struct hrtimer_sleeper t;
732 struct timespec tu;
733 ktime_t rem;
734
735 hrtimer_init(&t.timer, clockid, mode);
736 t.timer.expires = timespec_to_ktime(*rqtp);
737 if (do_nanosleep(&t, mode))
738 return 0;
739
740 /* Absolute timers do not update the rmtp value and restart: */
741 if (mode == HRTIMER_ABS)
742 return -ERESTARTNOHAND;
743
744 if (rmtp) {
745 rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
746 if (rem.tv64 <= 0)
747 return 0;
748 tu = ktime_to_timespec(rem);
749 if (copy_to_user(rmtp, &tu, sizeof(tu)))
750 return -EFAULT;
751 }
752
753 restart = &current_thread_info()->restart_block;
754 restart->fn = hrtimer_nanosleep_restart;
755 restart->arg0 = (unsigned long) t.timer.base->index;
756 restart->arg1 = (unsigned long) rmtp;
757 restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF;
758 restart->arg3 = t.timer.expires.tv64 >> 32;
759
760 return -ERESTART_RESTARTBLOCK;
761}
762
763asmlinkage long
764sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
765{
766 struct timespec tu;
767
768 if (copy_from_user(&tu, rqtp, sizeof(tu)))
769 return -EFAULT;
770
771 if (!timespec_valid(&tu))
772 return -EINVAL;
773
774 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_REL, CLOCK_MONOTONIC);
775}
776
777/*
778 * Functions related to boot-time initialization:
779 */
780static void __devinit init_hrtimers_cpu(int cpu)
781{
782 struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
783 int i;
784
785 for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
786 spin_lock_init(&base->lock);
787 lockdep_set_class(&base->lock, &base->lock_key);
788 }
789}
790
791#ifdef CONFIG_HOTPLUG_CPU
792
793static void migrate_hrtimer_list(struct hrtimer_base *old_base,
794 struct hrtimer_base *new_base)
795{
796 struct hrtimer *timer;
797 struct rb_node *node;
798
799 while ((node = rb_first(&old_base->active))) {
800 timer = rb_entry(node, struct hrtimer, node);
801 __remove_hrtimer(timer, old_base);
802 timer->base = new_base;
803 enqueue_hrtimer(timer, new_base);
804 }
805}
806
807static void migrate_hrtimers(int cpu)
808{
809 struct hrtimer_base *old_base, *new_base;
810 int i;
811
812 BUG_ON(cpu_online(cpu));
813 old_base = per_cpu(hrtimer_bases, cpu);
814 new_base = get_cpu_var(hrtimer_bases);
815
816 local_irq_disable();
817
818 for (i = 0; i < MAX_HRTIMER_BASES; i++) {
819
820 spin_lock(&new_base->lock);
821 spin_lock(&old_base->lock);
822
823 BUG_ON(old_base->curr_timer);
824
825 migrate_hrtimer_list(old_base, new_base);
826
827 spin_unlock(&old_base->lock);
828 spin_unlock(&new_base->lock);
829 old_base++;
830 new_base++;
831 }
832
833 local_irq_enable();
834 put_cpu_var(hrtimer_bases);
835}
836#endif /* CONFIG_HOTPLUG_CPU */
837
838static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
839 unsigned long action, void *hcpu)
840{
841 long cpu = (long)hcpu;
842
843 switch (action) {
844
845 case CPU_UP_PREPARE:
846 init_hrtimers_cpu(cpu);
847 break;
848
849#ifdef CONFIG_HOTPLUG_CPU
850 case CPU_DEAD:
851 migrate_hrtimers(cpu);
852 break;
853#endif
854
855 default:
856 break;
857 }
858
859 return NOTIFY_OK;
860}
861
862static struct notifier_block __cpuinitdata hrtimers_nb = {
863 .notifier_call = hrtimer_cpu_notify,
864};
865
866void __init hrtimers_init(void)
867{
868 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
869 (void *)(long)smp_processor_id());
870 register_cpu_notifier(&hrtimers_nb);
871}
872