gpio: build fixes
[linux-ginger.git] / kernel / hrtimer.c
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1 /*
2 * linux/kernel/hrtimer.c
4 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
6 * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
8 * High-resolution kernel timers
10 * In contrast to the low-resolution timeout API implemented in
11 * kernel/timer.c, hrtimers provide finer resolution and accuracy
12 * depending on system configuration and capabilities.
14 * These timers are currently used for:
15 * - itimers
16 * - POSIX timers
17 * - nanosleep
18 * - precise in-kernel timing
20 * Started by: Thomas Gleixner and Ingo Molnar
22 * Credits:
23 * based on kernel/timer.c
25 * Help, testing, suggestions, bugfixes, improvements were
26 * provided by:
28 * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
29 * et. al.
31 * For licencing details see kernel-base/COPYING
34 #include <linux/cpu.h>
35 #include <linux/irq.h>
36 #include <linux/module.h>
37 #include <linux/percpu.h>
38 #include <linux/hrtimer.h>
39 #include <linux/notifier.h>
40 #include <linux/syscalls.h>
41 #include <linux/kallsyms.h>
42 #include <linux/interrupt.h>
43 #include <linux/tick.h>
44 #include <linux/seq_file.h>
45 #include <linux/err.h>
46 #include <linux/debugobjects.h>
48 #include <asm/uaccess.h>
50 /**
51 * ktime_get - get the monotonic time in ktime_t format
53 * returns the time in ktime_t format
55 ktime_t ktime_get(void)
57 struct timespec now;
59 ktime_get_ts(&now);
61 return timespec_to_ktime(now);
63 EXPORT_SYMBOL_GPL(ktime_get);
65 /**
66 * ktime_get_real - get the real (wall-) time in ktime_t format
68 * returns the time in ktime_t format
70 ktime_t ktime_get_real(void)
72 struct timespec now;
74 getnstimeofday(&now);
76 return timespec_to_ktime(now);
79 EXPORT_SYMBOL_GPL(ktime_get_real);
82 * The timer bases:
84 * Note: If we want to add new timer bases, we have to skip the two
85 * clock ids captured by the cpu-timers. We do this by holding empty
86 * entries rather than doing math adjustment of the clock ids.
87 * This ensures that we capture erroneous accesses to these clock ids
88 * rather than moving them into the range of valid clock id's.
90 DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
93 .clock_base =
96 .index = CLOCK_REALTIME,
97 .get_time = &ktime_get_real,
98 .resolution = KTIME_LOW_RES,
101 .index = CLOCK_MONOTONIC,
102 .get_time = &ktime_get,
103 .resolution = KTIME_LOW_RES,
109 * ktime_get_ts - get the monotonic clock in timespec format
110 * @ts: pointer to timespec variable
112 * The function calculates the monotonic clock from the realtime
113 * clock and the wall_to_monotonic offset and stores the result
114 * in normalized timespec format in the variable pointed to by @ts.
116 void ktime_get_ts(struct timespec *ts)
118 struct timespec tomono;
119 unsigned long seq;
121 do {
122 seq = read_seqbegin(&xtime_lock);
123 getnstimeofday(ts);
124 tomono = wall_to_monotonic;
126 } while (read_seqretry(&xtime_lock, seq));
128 set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
129 ts->tv_nsec + tomono.tv_nsec);
131 EXPORT_SYMBOL_GPL(ktime_get_ts);
134 * Get the coarse grained time at the softirq based on xtime and
135 * wall_to_monotonic.
137 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
139 ktime_t xtim, tomono;
140 struct timespec xts, tom;
141 unsigned long seq;
143 do {
144 seq = read_seqbegin(&xtime_lock);
145 xts = current_kernel_time();
146 tom = wall_to_monotonic;
147 } while (read_seqretry(&xtime_lock, seq));
149 xtim = timespec_to_ktime(xts);
150 tomono = timespec_to_ktime(tom);
151 base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
152 base->clock_base[CLOCK_MONOTONIC].softirq_time =
153 ktime_add(xtim, tomono);
157 * Functions and macros which are different for UP/SMP systems are kept in a
158 * single place
160 #ifdef CONFIG_SMP
163 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
164 * means that all timers which are tied to this base via timer->base are
165 * locked, and the base itself is locked too.
167 * So __run_timers/migrate_timers can safely modify all timers which could
168 * be found on the lists/queues.
170 * When the timer's base is locked, and the timer removed from list, it is
171 * possible to set timer->base = NULL and drop the lock: the timer remains
172 * locked.
174 static
175 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
176 unsigned long *flags)
178 struct hrtimer_clock_base *base;
180 for (;;) {
181 base = timer->base;
182 if (likely(base != NULL)) {
183 spin_lock_irqsave(&base->cpu_base->lock, *flags);
184 if (likely(base == timer->base))
185 return base;
186 /* The timer has migrated to another CPU: */
187 spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
189 cpu_relax();
194 * Switch the timer base to the current CPU when possible.
196 static inline struct hrtimer_clock_base *
197 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base)
199 struct hrtimer_clock_base *new_base;
200 struct hrtimer_cpu_base *new_cpu_base;
202 new_cpu_base = &__get_cpu_var(hrtimer_bases);
203 new_base = &new_cpu_base->clock_base[base->index];
205 if (base != new_base) {
207 * We are trying to schedule the timer on the local CPU.
208 * However we can't change timer's base while it is running,
209 * so we keep it on the same CPU. No hassle vs. reprogramming
210 * the event source in the high resolution case. The softirq
211 * code will take care of this when the timer function has
212 * completed. There is no conflict as we hold the lock until
213 * the timer is enqueued.
215 if (unlikely(hrtimer_callback_running(timer)))
216 return base;
218 /* See the comment in lock_timer_base() */
219 timer->base = NULL;
220 spin_unlock(&base->cpu_base->lock);
221 spin_lock(&new_base->cpu_base->lock);
222 timer->base = new_base;
224 return new_base;
227 #else /* CONFIG_SMP */
229 static inline struct hrtimer_clock_base *
230 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
232 struct hrtimer_clock_base *base = timer->base;
234 spin_lock_irqsave(&base->cpu_base->lock, *flags);
236 return base;
239 # define switch_hrtimer_base(t, b) (b)
241 #endif /* !CONFIG_SMP */
244 * Functions for the union type storage format of ktime_t which are
245 * too large for inlining:
247 #if BITS_PER_LONG < 64
248 # ifndef CONFIG_KTIME_SCALAR
250 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
251 * @kt: addend
252 * @nsec: the scalar nsec value to add
254 * Returns the sum of kt and nsec in ktime_t format
256 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
258 ktime_t tmp;
260 if (likely(nsec < NSEC_PER_SEC)) {
261 tmp.tv64 = nsec;
262 } else {
263 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
265 tmp = ktime_set((long)nsec, rem);
268 return ktime_add(kt, tmp);
271 EXPORT_SYMBOL_GPL(ktime_add_ns);
274 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
275 * @kt: minuend
276 * @nsec: the scalar nsec value to subtract
278 * Returns the subtraction of @nsec from @kt in ktime_t format
280 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
282 ktime_t tmp;
284 if (likely(nsec < NSEC_PER_SEC)) {
285 tmp.tv64 = nsec;
286 } else {
287 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
289 tmp = ktime_set((long)nsec, rem);
292 return ktime_sub(kt, tmp);
295 EXPORT_SYMBOL_GPL(ktime_sub_ns);
296 # endif /* !CONFIG_KTIME_SCALAR */
299 * Divide a ktime value by a nanosecond value
301 u64 ktime_divns(const ktime_t kt, s64 div)
303 u64 dclc, inc, dns;
304 int sft = 0;
306 dclc = dns = ktime_to_ns(kt);
307 inc = div;
308 /* Make sure the divisor is less than 2^32: */
309 while (div >> 32) {
310 sft++;
311 div >>= 1;
313 dclc >>= sft;
314 do_div(dclc, (unsigned long) div);
316 return dclc;
318 #endif /* BITS_PER_LONG >= 64 */
321 * Add two ktime values and do a safety check for overflow:
323 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
325 ktime_t res = ktime_add(lhs, rhs);
328 * We use KTIME_SEC_MAX here, the maximum timeout which we can
329 * return to user space in a timespec:
331 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
332 res = ktime_set(KTIME_SEC_MAX, 0);
334 return res;
337 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
339 static struct debug_obj_descr hrtimer_debug_descr;
342 * fixup_init is called when:
343 * - an active object is initialized
345 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
347 struct hrtimer *timer = addr;
349 switch (state) {
350 case ODEBUG_STATE_ACTIVE:
351 hrtimer_cancel(timer);
352 debug_object_init(timer, &hrtimer_debug_descr);
353 return 1;
354 default:
355 return 0;
360 * fixup_activate is called when:
361 * - an active object is activated
362 * - an unknown object is activated (might be a statically initialized object)
364 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
366 switch (state) {
368 case ODEBUG_STATE_NOTAVAILABLE:
369 WARN_ON_ONCE(1);
370 return 0;
372 case ODEBUG_STATE_ACTIVE:
373 WARN_ON(1);
375 default:
376 return 0;
381 * fixup_free is called when:
382 * - an active object is freed
384 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
386 struct hrtimer *timer = addr;
388 switch (state) {
389 case ODEBUG_STATE_ACTIVE:
390 hrtimer_cancel(timer);
391 debug_object_free(timer, &hrtimer_debug_descr);
392 return 1;
393 default:
394 return 0;
398 static struct debug_obj_descr hrtimer_debug_descr = {
399 .name = "hrtimer",
400 .fixup_init = hrtimer_fixup_init,
401 .fixup_activate = hrtimer_fixup_activate,
402 .fixup_free = hrtimer_fixup_free,
405 static inline void debug_hrtimer_init(struct hrtimer *timer)
407 debug_object_init(timer, &hrtimer_debug_descr);
410 static inline void debug_hrtimer_activate(struct hrtimer *timer)
412 debug_object_activate(timer, &hrtimer_debug_descr);
415 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
417 debug_object_deactivate(timer, &hrtimer_debug_descr);
420 static inline void debug_hrtimer_free(struct hrtimer *timer)
422 debug_object_free(timer, &hrtimer_debug_descr);
425 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
426 enum hrtimer_mode mode);
428 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
429 enum hrtimer_mode mode)
431 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
432 __hrtimer_init(timer, clock_id, mode);
435 void destroy_hrtimer_on_stack(struct hrtimer *timer)
437 debug_object_free(timer, &hrtimer_debug_descr);
440 #else
441 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
442 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
443 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
444 #endif
447 * Check, whether the timer is on the callback pending list
449 static inline int hrtimer_cb_pending(const struct hrtimer *timer)
451 return timer->state & HRTIMER_STATE_PENDING;
455 * Remove a timer from the callback pending list
457 static inline void hrtimer_remove_cb_pending(struct hrtimer *timer)
459 list_del_init(&timer->cb_entry);
462 /* High resolution timer related functions */
463 #ifdef CONFIG_HIGH_RES_TIMERS
466 * High resolution timer enabled ?
468 static int hrtimer_hres_enabled __read_mostly = 1;
471 * Enable / Disable high resolution mode
473 static int __init setup_hrtimer_hres(char *str)
475 if (!strcmp(str, "off"))
476 hrtimer_hres_enabled = 0;
477 else if (!strcmp(str, "on"))
478 hrtimer_hres_enabled = 1;
479 else
480 return 0;
481 return 1;
484 __setup("highres=", setup_hrtimer_hres);
487 * hrtimer_high_res_enabled - query, if the highres mode is enabled
489 static inline int hrtimer_is_hres_enabled(void)
491 return hrtimer_hres_enabled;
495 * Is the high resolution mode active ?
497 static inline int hrtimer_hres_active(void)
499 return __get_cpu_var(hrtimer_bases).hres_active;
503 * Reprogram the event source with checking both queues for the
504 * next event
505 * Called with interrupts disabled and base->lock held
507 static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base)
509 int i;
510 struct hrtimer_clock_base *base = cpu_base->clock_base;
511 ktime_t expires;
513 cpu_base->expires_next.tv64 = KTIME_MAX;
515 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
516 struct hrtimer *timer;
518 if (!base->first)
519 continue;
520 timer = rb_entry(base->first, struct hrtimer, node);
521 expires = ktime_sub(timer->expires, base->offset);
522 if (expires.tv64 < cpu_base->expires_next.tv64)
523 cpu_base->expires_next = expires;
526 if (cpu_base->expires_next.tv64 != KTIME_MAX)
527 tick_program_event(cpu_base->expires_next, 1);
531 * Shared reprogramming for clock_realtime and clock_monotonic
533 * When a timer is enqueued and expires earlier than the already enqueued
534 * timers, we have to check, whether it expires earlier than the timer for
535 * which the clock event device was armed.
537 * Called with interrupts disabled and base->cpu_base.lock held
539 static int hrtimer_reprogram(struct hrtimer *timer,
540 struct hrtimer_clock_base *base)
542 ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
543 ktime_t expires = ktime_sub(timer->expires, base->offset);
544 int res;
546 WARN_ON_ONCE(timer->expires.tv64 < 0);
549 * When the callback is running, we do not reprogram the clock event
550 * device. The timer callback is either running on a different CPU or
551 * the callback is executed in the hrtimer_interrupt context. The
552 * reprogramming is handled either by the softirq, which called the
553 * callback or at the end of the hrtimer_interrupt.
555 if (hrtimer_callback_running(timer))
556 return 0;
559 * CLOCK_REALTIME timer might be requested with an absolute
560 * expiry time which is less than base->offset. Nothing wrong
561 * about that, just avoid to call into the tick code, which
562 * has now objections against negative expiry values.
564 if (expires.tv64 < 0)
565 return -ETIME;
567 if (expires.tv64 >= expires_next->tv64)
568 return 0;
571 * Clockevents returns -ETIME, when the event was in the past.
573 res = tick_program_event(expires, 0);
574 if (!IS_ERR_VALUE(res))
575 *expires_next = expires;
576 return res;
581 * Retrigger next event is called after clock was set
583 * Called with interrupts disabled via on_each_cpu()
585 static void retrigger_next_event(void *arg)
587 struct hrtimer_cpu_base *base;
588 struct timespec realtime_offset;
589 unsigned long seq;
591 if (!hrtimer_hres_active())
592 return;
594 do {
595 seq = read_seqbegin(&xtime_lock);
596 set_normalized_timespec(&realtime_offset,
597 -wall_to_monotonic.tv_sec,
598 -wall_to_monotonic.tv_nsec);
599 } while (read_seqretry(&xtime_lock, seq));
601 base = &__get_cpu_var(hrtimer_bases);
603 /* Adjust CLOCK_REALTIME offset */
604 spin_lock(&base->lock);
605 base->clock_base[CLOCK_REALTIME].offset =
606 timespec_to_ktime(realtime_offset);
608 hrtimer_force_reprogram(base);
609 spin_unlock(&base->lock);
613 * Clock realtime was set
615 * Change the offset of the realtime clock vs. the monotonic
616 * clock.
618 * We might have to reprogram the high resolution timer interrupt. On
619 * SMP we call the architecture specific code to retrigger _all_ high
620 * resolution timer interrupts. On UP we just disable interrupts and
621 * call the high resolution interrupt code.
623 void clock_was_set(void)
625 /* Retrigger the CPU local events everywhere */
626 on_each_cpu(retrigger_next_event, NULL, 0, 1);
630 * During resume we might have to reprogram the high resolution timer
631 * interrupt (on the local CPU):
633 void hres_timers_resume(void)
635 WARN_ON_ONCE(num_online_cpus() > 1);
637 /* Retrigger the CPU local events: */
638 retrigger_next_event(NULL);
642 * Initialize the high resolution related parts of cpu_base
644 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
646 base->expires_next.tv64 = KTIME_MAX;
647 base->hres_active = 0;
651 * Initialize the high resolution related parts of a hrtimer
653 static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
658 * When High resolution timers are active, try to reprogram. Note, that in case
659 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
660 * check happens. The timer gets enqueued into the rbtree. The reprogramming
661 * and expiry check is done in the hrtimer_interrupt or in the softirq.
663 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
664 struct hrtimer_clock_base *base)
666 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
668 /* Timer is expired, act upon the callback mode */
669 switch(timer->cb_mode) {
670 case HRTIMER_CB_IRQSAFE_NO_RESTART:
671 debug_hrtimer_deactivate(timer);
673 * We can call the callback from here. No restart
674 * happens, so no danger of recursion
676 BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
677 return 1;
678 case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ:
680 * This is solely for the sched tick emulation with
681 * dynamic tick support to ensure that we do not
682 * restart the tick right on the edge and end up with
683 * the tick timer in the softirq ! The calling site
684 * takes care of this.
686 debug_hrtimer_deactivate(timer);
687 return 1;
688 case HRTIMER_CB_IRQSAFE:
689 case HRTIMER_CB_SOFTIRQ:
691 * Move everything else into the softirq pending list !
693 list_add_tail(&timer->cb_entry,
694 &base->cpu_base->cb_pending);
695 timer->state = HRTIMER_STATE_PENDING;
696 return 1;
697 default:
698 BUG();
701 return 0;
705 * Switch to high resolution mode
707 static int hrtimer_switch_to_hres(void)
709 int cpu = smp_processor_id();
710 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
711 unsigned long flags;
713 if (base->hres_active)
714 return 1;
716 local_irq_save(flags);
718 if (tick_init_highres()) {
719 local_irq_restore(flags);
720 printk(KERN_WARNING "Could not switch to high resolution "
721 "mode on CPU %d\n", cpu);
722 return 0;
724 base->hres_active = 1;
725 base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES;
726 base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES;
728 tick_setup_sched_timer();
730 /* "Retrigger" the interrupt to get things going */
731 retrigger_next_event(NULL);
732 local_irq_restore(flags);
733 printk(KERN_DEBUG "Switched to high resolution mode on CPU %d\n",
734 smp_processor_id());
735 return 1;
738 static inline void hrtimer_raise_softirq(void)
740 raise_softirq(HRTIMER_SOFTIRQ);
743 #else
745 static inline int hrtimer_hres_active(void) { return 0; }
746 static inline int hrtimer_is_hres_enabled(void) { return 0; }
747 static inline int hrtimer_switch_to_hres(void) { return 0; }
748 static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { }
749 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
750 struct hrtimer_clock_base *base)
752 return 0;
754 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
755 static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
756 static inline int hrtimer_reprogram(struct hrtimer *timer,
757 struct hrtimer_clock_base *base)
759 return 0;
761 static inline void hrtimer_raise_softirq(void) { }
763 #endif /* CONFIG_HIGH_RES_TIMERS */
765 #ifdef CONFIG_TIMER_STATS
766 void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr)
768 if (timer->start_site)
769 return;
771 timer->start_site = addr;
772 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
773 timer->start_pid = current->pid;
775 #endif
778 * Counterpart to lock_hrtimer_base above:
780 static inline
781 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
783 spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
787 * hrtimer_forward - forward the timer expiry
788 * @timer: hrtimer to forward
789 * @now: forward past this time
790 * @interval: the interval to forward
792 * Forward the timer expiry so it will expire in the future.
793 * Returns the number of overruns.
795 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
797 u64 orun = 1;
798 ktime_t delta;
800 delta = ktime_sub(now, timer->expires);
802 if (delta.tv64 < 0)
803 return 0;
805 if (interval.tv64 < timer->base->resolution.tv64)
806 interval.tv64 = timer->base->resolution.tv64;
808 if (unlikely(delta.tv64 >= interval.tv64)) {
809 s64 incr = ktime_to_ns(interval);
811 orun = ktime_divns(delta, incr);
812 timer->expires = ktime_add_ns(timer->expires, incr * orun);
813 if (timer->expires.tv64 > now.tv64)
814 return orun;
816 * This (and the ktime_add() below) is the
817 * correction for exact:
819 orun++;
821 timer->expires = ktime_add_safe(timer->expires, interval);
823 return orun;
825 EXPORT_SYMBOL_GPL(hrtimer_forward);
828 * enqueue_hrtimer - internal function to (re)start a timer
830 * The timer is inserted in expiry order. Insertion into the
831 * red black tree is O(log(n)). Must hold the base lock.
833 static void enqueue_hrtimer(struct hrtimer *timer,
834 struct hrtimer_clock_base *base, int reprogram)
836 struct rb_node **link = &base->active.rb_node;
837 struct rb_node *parent = NULL;
838 struct hrtimer *entry;
839 int leftmost = 1;
841 debug_hrtimer_activate(timer);
844 * Find the right place in the rbtree:
846 while (*link) {
847 parent = *link;
848 entry = rb_entry(parent, struct hrtimer, node);
850 * We dont care about collisions. Nodes with
851 * the same expiry time stay together.
853 if (timer->expires.tv64 < entry->expires.tv64) {
854 link = &(*link)->rb_left;
855 } else {
856 link = &(*link)->rb_right;
857 leftmost = 0;
862 * Insert the timer to the rbtree and check whether it
863 * replaces the first pending timer
865 if (leftmost) {
867 * Reprogram the clock event device. When the timer is already
868 * expired hrtimer_enqueue_reprogram has either called the
869 * callback or added it to the pending list and raised the
870 * softirq.
872 * This is a NOP for !HIGHRES
874 if (reprogram && hrtimer_enqueue_reprogram(timer, base))
875 return;
877 base->first = &timer->node;
880 rb_link_node(&timer->node, parent, link);
881 rb_insert_color(&timer->node, &base->active);
883 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
884 * state of a possibly running callback.
886 timer->state |= HRTIMER_STATE_ENQUEUED;
890 * __remove_hrtimer - internal function to remove a timer
892 * Caller must hold the base lock.
894 * High resolution timer mode reprograms the clock event device when the
895 * timer is the one which expires next. The caller can disable this by setting
896 * reprogram to zero. This is useful, when the context does a reprogramming
897 * anyway (e.g. timer interrupt)
899 static void __remove_hrtimer(struct hrtimer *timer,
900 struct hrtimer_clock_base *base,
901 unsigned long newstate, int reprogram)
903 /* High res. callback list. NOP for !HIGHRES */
904 if (hrtimer_cb_pending(timer))
905 hrtimer_remove_cb_pending(timer);
906 else {
908 * Remove the timer from the rbtree and replace the
909 * first entry pointer if necessary.
911 if (base->first == &timer->node) {
912 base->first = rb_next(&timer->node);
913 /* Reprogram the clock event device. if enabled */
914 if (reprogram && hrtimer_hres_active())
915 hrtimer_force_reprogram(base->cpu_base);
917 rb_erase(&timer->node, &base->active);
919 timer->state = newstate;
923 * remove hrtimer, called with base lock held
925 static inline int
926 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
928 if (hrtimer_is_queued(timer)) {
929 int reprogram;
932 * Remove the timer and force reprogramming when high
933 * resolution mode is active and the timer is on the current
934 * CPU. If we remove a timer on another CPU, reprogramming is
935 * skipped. The interrupt event on this CPU is fired and
936 * reprogramming happens in the interrupt handler. This is a
937 * rare case and less expensive than a smp call.
939 debug_hrtimer_deactivate(timer);
940 timer_stats_hrtimer_clear_start_info(timer);
941 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
942 __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
943 reprogram);
944 return 1;
946 return 0;
950 * hrtimer_start - (re)start an relative timer on the current CPU
951 * @timer: the timer to be added
952 * @tim: expiry time
953 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
955 * Returns:
956 * 0 on success
957 * 1 when the timer was active
960 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
962 struct hrtimer_clock_base *base, *new_base;
963 unsigned long flags;
964 int ret, raise;
966 base = lock_hrtimer_base(timer, &flags);
968 /* Remove an active timer from the queue: */
969 ret = remove_hrtimer(timer, base);
971 /* Switch the timer base, if necessary: */
972 new_base = switch_hrtimer_base(timer, base);
974 if (mode == HRTIMER_MODE_REL) {
975 tim = ktime_add_safe(tim, new_base->get_time());
977 * CONFIG_TIME_LOW_RES is a temporary way for architectures
978 * to signal that they simply return xtime in
979 * do_gettimeoffset(). In this case we want to round up by
980 * resolution when starting a relative timer, to avoid short
981 * timeouts. This will go away with the GTOD framework.
983 #ifdef CONFIG_TIME_LOW_RES
984 tim = ktime_add_safe(tim, base->resolution);
985 #endif
988 timer->expires = tim;
990 timer_stats_hrtimer_set_start_info(timer);
993 * Only allow reprogramming if the new base is on this CPU.
994 * (it might still be on another CPU if the timer was pending)
996 enqueue_hrtimer(timer, new_base,
997 new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
1000 * The timer may be expired and moved to the cb_pending
1001 * list. We can not raise the softirq with base lock held due
1002 * to a possible deadlock with runqueue lock.
1004 raise = timer->state == HRTIMER_STATE_PENDING;
1006 unlock_hrtimer_base(timer, &flags);
1008 if (raise)
1009 hrtimer_raise_softirq();
1011 return ret;
1013 EXPORT_SYMBOL_GPL(hrtimer_start);
1016 * hrtimer_try_to_cancel - try to deactivate a timer
1017 * @timer: hrtimer to stop
1019 * Returns:
1020 * 0 when the timer was not active
1021 * 1 when the timer was active
1022 * -1 when the timer is currently excuting the callback function and
1023 * cannot be stopped
1025 int hrtimer_try_to_cancel(struct hrtimer *timer)
1027 struct hrtimer_clock_base *base;
1028 unsigned long flags;
1029 int ret = -1;
1031 base = lock_hrtimer_base(timer, &flags);
1033 if (!hrtimer_callback_running(timer))
1034 ret = remove_hrtimer(timer, base);
1036 unlock_hrtimer_base(timer, &flags);
1038 return ret;
1041 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1044 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1045 * @timer: the timer to be cancelled
1047 * Returns:
1048 * 0 when the timer was not active
1049 * 1 when the timer was active
1051 int hrtimer_cancel(struct hrtimer *timer)
1053 for (;;) {
1054 int ret = hrtimer_try_to_cancel(timer);
1056 if (ret >= 0)
1057 return ret;
1058 cpu_relax();
1061 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1064 * hrtimer_get_remaining - get remaining time for the timer
1065 * @timer: the timer to read
1067 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1069 struct hrtimer_clock_base *base;
1070 unsigned long flags;
1071 ktime_t rem;
1073 base = lock_hrtimer_base(timer, &flags);
1074 rem = ktime_sub(timer->expires, base->get_time());
1075 unlock_hrtimer_base(timer, &flags);
1077 return rem;
1079 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1081 #if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)
1083 * hrtimer_get_next_event - get the time until next expiry event
1085 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1086 * is pending.
1088 ktime_t hrtimer_get_next_event(void)
1090 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1091 struct hrtimer_clock_base *base = cpu_base->clock_base;
1092 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1093 unsigned long flags;
1094 int i;
1096 spin_lock_irqsave(&cpu_base->lock, flags);
1098 if (!hrtimer_hres_active()) {
1099 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1100 struct hrtimer *timer;
1102 if (!base->first)
1103 continue;
1105 timer = rb_entry(base->first, struct hrtimer, node);
1106 delta.tv64 = timer->expires.tv64;
1107 delta = ktime_sub(delta, base->get_time());
1108 if (delta.tv64 < mindelta.tv64)
1109 mindelta.tv64 = delta.tv64;
1113 spin_unlock_irqrestore(&cpu_base->lock, flags);
1115 if (mindelta.tv64 < 0)
1116 mindelta.tv64 = 0;
1117 return mindelta;
1119 #endif
1121 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1122 enum hrtimer_mode mode)
1124 struct hrtimer_cpu_base *cpu_base;
1126 memset(timer, 0, sizeof(struct hrtimer));
1128 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1130 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1131 clock_id = CLOCK_MONOTONIC;
1133 timer->base = &cpu_base->clock_base[clock_id];
1134 INIT_LIST_HEAD(&timer->cb_entry);
1135 hrtimer_init_timer_hres(timer);
1137 #ifdef CONFIG_TIMER_STATS
1138 timer->start_site = NULL;
1139 timer->start_pid = -1;
1140 memset(timer->start_comm, 0, TASK_COMM_LEN);
1141 #endif
1145 * hrtimer_init - initialize a timer to the given clock
1146 * @timer: the timer to be initialized
1147 * @clock_id: the clock to be used
1148 * @mode: timer mode abs/rel
1150 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1151 enum hrtimer_mode mode)
1153 debug_hrtimer_init(timer);
1154 __hrtimer_init(timer, clock_id, mode);
1156 EXPORT_SYMBOL_GPL(hrtimer_init);
1159 * hrtimer_get_res - get the timer resolution for a clock
1160 * @which_clock: which clock to query
1161 * @tp: pointer to timespec variable to store the resolution
1163 * Store the resolution of the clock selected by @which_clock in the
1164 * variable pointed to by @tp.
1166 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1168 struct hrtimer_cpu_base *cpu_base;
1170 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1171 *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
1173 return 0;
1175 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1177 static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
1179 spin_lock_irq(&cpu_base->lock);
1181 while (!list_empty(&cpu_base->cb_pending)) {
1182 enum hrtimer_restart (*fn)(struct hrtimer *);
1183 struct hrtimer *timer;
1184 int restart;
1186 timer = list_entry(cpu_base->cb_pending.next,
1187 struct hrtimer, cb_entry);
1189 debug_hrtimer_deactivate(timer);
1190 timer_stats_account_hrtimer(timer);
1192 fn = timer->function;
1193 __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
1194 spin_unlock_irq(&cpu_base->lock);
1196 restart = fn(timer);
1198 spin_lock_irq(&cpu_base->lock);
1200 timer->state &= ~HRTIMER_STATE_CALLBACK;
1201 if (restart == HRTIMER_RESTART) {
1202 BUG_ON(hrtimer_active(timer));
1204 * Enqueue the timer, allow reprogramming of the event
1205 * device
1207 enqueue_hrtimer(timer, timer->base, 1);
1208 } else if (hrtimer_active(timer)) {
1210 * If the timer was rearmed on another CPU, reprogram
1211 * the event device.
1213 struct hrtimer_clock_base *base = timer->base;
1215 if (base->first == &timer->node &&
1216 hrtimer_reprogram(timer, base)) {
1218 * Timer is expired. Thus move it from tree to
1219 * pending list again.
1221 __remove_hrtimer(timer, base,
1222 HRTIMER_STATE_PENDING, 0);
1223 list_add_tail(&timer->cb_entry,
1224 &base->cpu_base->cb_pending);
1228 spin_unlock_irq(&cpu_base->lock);
1231 static void __run_hrtimer(struct hrtimer *timer)
1233 struct hrtimer_clock_base *base = timer->base;
1234 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1235 enum hrtimer_restart (*fn)(struct hrtimer *);
1236 int restart;
1238 debug_hrtimer_deactivate(timer);
1239 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1240 timer_stats_account_hrtimer(timer);
1242 fn = timer->function;
1243 if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) {
1245 * Used for scheduler timers, avoid lock inversion with
1246 * rq->lock and tasklist_lock.
1248 * These timers are required to deal with enqueue expiry
1249 * themselves and are not allowed to migrate.
1251 spin_unlock(&cpu_base->lock);
1252 restart = fn(timer);
1253 spin_lock(&cpu_base->lock);
1254 } else
1255 restart = fn(timer);
1258 * Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid
1259 * reprogramming of the event hardware. This happens at the end of this
1260 * function anyway.
1262 if (restart != HRTIMER_NORESTART) {
1263 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1264 enqueue_hrtimer(timer, base, 0);
1266 timer->state &= ~HRTIMER_STATE_CALLBACK;
1269 #ifdef CONFIG_HIGH_RES_TIMERS
1272 * High resolution timer interrupt
1273 * Called with interrupts disabled
1275 void hrtimer_interrupt(struct clock_event_device *dev)
1277 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1278 struct hrtimer_clock_base *base;
1279 ktime_t expires_next, now;
1280 int i, raise = 0;
1282 BUG_ON(!cpu_base->hres_active);
1283 cpu_base->nr_events++;
1284 dev->next_event.tv64 = KTIME_MAX;
1286 retry:
1287 now = ktime_get();
1289 expires_next.tv64 = KTIME_MAX;
1291 base = cpu_base->clock_base;
1293 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1294 ktime_t basenow;
1295 struct rb_node *node;
1297 spin_lock(&cpu_base->lock);
1299 basenow = ktime_add(now, base->offset);
1301 while ((node = base->first)) {
1302 struct hrtimer *timer;
1304 timer = rb_entry(node, struct hrtimer, node);
1306 if (basenow.tv64 < timer->expires.tv64) {
1307 ktime_t expires;
1309 expires = ktime_sub(timer->expires,
1310 base->offset);
1311 if (expires.tv64 < expires_next.tv64)
1312 expires_next = expires;
1313 break;
1316 /* Move softirq callbacks to the pending list */
1317 if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
1318 __remove_hrtimer(timer, base,
1319 HRTIMER_STATE_PENDING, 0);
1320 list_add_tail(&timer->cb_entry,
1321 &base->cpu_base->cb_pending);
1322 raise = 1;
1323 continue;
1326 __run_hrtimer(timer);
1328 spin_unlock(&cpu_base->lock);
1329 base++;
1332 cpu_base->expires_next = expires_next;
1334 /* Reprogramming necessary ? */
1335 if (expires_next.tv64 != KTIME_MAX) {
1336 if (tick_program_event(expires_next, 0))
1337 goto retry;
1340 /* Raise softirq ? */
1341 if (raise)
1342 raise_softirq(HRTIMER_SOFTIRQ);
1345 static void run_hrtimer_softirq(struct softirq_action *h)
1347 run_hrtimer_pending(&__get_cpu_var(hrtimer_bases));
1350 #endif /* CONFIG_HIGH_RES_TIMERS */
1353 * Called from timer softirq every jiffy, expire hrtimers:
1355 * For HRT its the fall back code to run the softirq in the timer
1356 * softirq context in case the hrtimer initialization failed or has
1357 * not been done yet.
1359 void hrtimer_run_pending(void)
1361 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1363 if (hrtimer_hres_active())
1364 return;
1367 * This _is_ ugly: We have to check in the softirq context,
1368 * whether we can switch to highres and / or nohz mode. The
1369 * clocksource switch happens in the timer interrupt with
1370 * xtime_lock held. Notification from there only sets the
1371 * check bit in the tick_oneshot code, otherwise we might
1372 * deadlock vs. xtime_lock.
1374 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1375 hrtimer_switch_to_hres();
1377 run_hrtimer_pending(cpu_base);
1381 * Called from hardirq context every jiffy
1383 void hrtimer_run_queues(void)
1385 struct rb_node *node;
1386 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1387 struct hrtimer_clock_base *base;
1388 int index, gettime = 1;
1390 if (hrtimer_hres_active())
1391 return;
1393 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1394 base = &cpu_base->clock_base[index];
1396 if (!base->first)
1397 continue;
1399 if (base->get_softirq_time)
1400 base->softirq_time = base->get_softirq_time();
1401 else if (gettime) {
1402 hrtimer_get_softirq_time(cpu_base);
1403 gettime = 0;
1406 spin_lock(&cpu_base->lock);
1408 while ((node = base->first)) {
1409 struct hrtimer *timer;
1411 timer = rb_entry(node, struct hrtimer, node);
1412 if (base->softirq_time.tv64 <= timer->expires.tv64)
1413 break;
1415 if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
1416 __remove_hrtimer(timer, base,
1417 HRTIMER_STATE_PENDING, 0);
1418 list_add_tail(&timer->cb_entry,
1419 &base->cpu_base->cb_pending);
1420 continue;
1423 __run_hrtimer(timer);
1425 spin_unlock(&cpu_base->lock);
1430 * Sleep related functions:
1432 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1434 struct hrtimer_sleeper *t =
1435 container_of(timer, struct hrtimer_sleeper, timer);
1436 struct task_struct *task = t->task;
1438 t->task = NULL;
1439 if (task)
1440 wake_up_process(task);
1442 return HRTIMER_NORESTART;
1445 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1447 sl->timer.function = hrtimer_wakeup;
1448 sl->task = task;
1449 #ifdef CONFIG_HIGH_RES_TIMERS
1450 sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
1451 #endif
1454 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1456 hrtimer_init_sleeper(t, current);
1458 do {
1459 set_current_state(TASK_INTERRUPTIBLE);
1460 hrtimer_start(&t->timer, t->timer.expires, mode);
1461 if (!hrtimer_active(&t->timer))
1462 t->task = NULL;
1464 if (likely(t->task))
1465 schedule();
1467 hrtimer_cancel(&t->timer);
1468 mode = HRTIMER_MODE_ABS;
1470 } while (t->task && !signal_pending(current));
1472 __set_current_state(TASK_RUNNING);
1474 return t->task == NULL;
1477 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1479 struct timespec rmt;
1480 ktime_t rem;
1482 rem = ktime_sub(timer->expires, timer->base->get_time());
1483 if (rem.tv64 <= 0)
1484 return 0;
1485 rmt = ktime_to_timespec(rem);
1487 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1488 return -EFAULT;
1490 return 1;
1493 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1495 struct hrtimer_sleeper t;
1496 struct timespec __user *rmtp;
1497 int ret = 0;
1499 hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
1500 HRTIMER_MODE_ABS);
1501 t.timer.expires.tv64 = restart->nanosleep.expires;
1503 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1504 goto out;
1506 rmtp = restart->nanosleep.rmtp;
1507 if (rmtp) {
1508 ret = update_rmtp(&t.timer, rmtp);
1509 if (ret <= 0)
1510 goto out;
1513 /* The other values in restart are already filled in */
1514 ret = -ERESTART_RESTARTBLOCK;
1515 out:
1516 destroy_hrtimer_on_stack(&t.timer);
1517 return ret;
1520 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1521 const enum hrtimer_mode mode, const clockid_t clockid)
1523 struct restart_block *restart;
1524 struct hrtimer_sleeper t;
1525 int ret = 0;
1527 hrtimer_init_on_stack(&t.timer, clockid, mode);
1528 t.timer.expires = timespec_to_ktime(*rqtp);
1529 if (do_nanosleep(&t, mode))
1530 goto out;
1532 /* Absolute timers do not update the rmtp value and restart: */
1533 if (mode == HRTIMER_MODE_ABS) {
1534 ret = -ERESTARTNOHAND;
1535 goto out;
1538 if (rmtp) {
1539 ret = update_rmtp(&t.timer, rmtp);
1540 if (ret <= 0)
1541 goto out;
1544 restart = &current_thread_info()->restart_block;
1545 restart->fn = hrtimer_nanosleep_restart;
1546 restart->nanosleep.index = t.timer.base->index;
1547 restart->nanosleep.rmtp = rmtp;
1548 restart->nanosleep.expires = t.timer.expires.tv64;
1550 ret = -ERESTART_RESTARTBLOCK;
1551 out:
1552 destroy_hrtimer_on_stack(&t.timer);
1553 return ret;
1556 asmlinkage long
1557 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
1559 struct timespec tu;
1561 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1562 return -EFAULT;
1564 if (!timespec_valid(&tu))
1565 return -EINVAL;
1567 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1571 * Functions related to boot-time initialization:
1573 static void __cpuinit init_hrtimers_cpu(int cpu)
1575 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1576 int i;
1578 spin_lock_init(&cpu_base->lock);
1580 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
1581 cpu_base->clock_base[i].cpu_base = cpu_base;
1583 INIT_LIST_HEAD(&cpu_base->cb_pending);
1584 hrtimer_init_hres(cpu_base);
1587 #ifdef CONFIG_HOTPLUG_CPU
1589 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1590 struct hrtimer_clock_base *new_base)
1592 struct hrtimer *timer;
1593 struct rb_node *node;
1595 while ((node = rb_first(&old_base->active))) {
1596 timer = rb_entry(node, struct hrtimer, node);
1597 BUG_ON(hrtimer_callback_running(timer));
1598 debug_hrtimer_deactivate(timer);
1599 __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
1600 timer->base = new_base;
1602 * Enqueue the timer. Allow reprogramming of the event device
1604 enqueue_hrtimer(timer, new_base, 1);
1608 static void migrate_hrtimers(int cpu)
1610 struct hrtimer_cpu_base *old_base, *new_base;
1611 int i;
1613 BUG_ON(cpu_online(cpu));
1614 old_base = &per_cpu(hrtimer_bases, cpu);
1615 new_base = &get_cpu_var(hrtimer_bases);
1617 tick_cancel_sched_timer(cpu);
1619 local_irq_disable();
1620 spin_lock(&new_base->lock);
1621 spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1623 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1624 migrate_hrtimer_list(&old_base->clock_base[i],
1625 &new_base->clock_base[i]);
1628 spin_unlock(&old_base->lock);
1629 spin_unlock(&new_base->lock);
1630 local_irq_enable();
1631 put_cpu_var(hrtimer_bases);
1633 #endif /* CONFIG_HOTPLUG_CPU */
1635 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1636 unsigned long action, void *hcpu)
1638 unsigned int cpu = (long)hcpu;
1640 switch (action) {
1642 case CPU_UP_PREPARE:
1643 case CPU_UP_PREPARE_FROZEN:
1644 init_hrtimers_cpu(cpu);
1645 break;
1647 #ifdef CONFIG_HOTPLUG_CPU
1648 case CPU_DEAD:
1649 case CPU_DEAD_FROZEN:
1650 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu);
1651 migrate_hrtimers(cpu);
1652 break;
1653 #endif
1655 default:
1656 break;
1659 return NOTIFY_OK;
1662 static struct notifier_block __cpuinitdata hrtimers_nb = {
1663 .notifier_call = hrtimer_cpu_notify,
1666 void __init hrtimers_init(void)
1668 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1669 (void *)(long)smp_processor_id());
1670 register_cpu_notifier(&hrtimers_nb);
1671 #ifdef CONFIG_HIGH_RES_TIMERS
1672 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
1673 #endif