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:
18 * - precise in-kernel timing
20 * Started by: Thomas Gleixner and Ingo Molnar
23 * based on kernel/timer.c
25 * Help, testing, suggestions, bugfixes, improvements were
28 * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
31 * For licencing details see kernel-base/COPYING
34 #include <linux/cpu.h>
35 #include <linux/export.h>
36 #include <linux/percpu.h>
37 #include <linux/hrtimer.h>
38 #include <linux/notifier.h>
39 #include <linux/syscalls.h>
40 #include <linux/kallsyms.h>
41 #include <linux/interrupt.h>
42 #include <linux/tick.h>
43 #include <linux/seq_file.h>
44 #include <linux/err.h>
45 #include <linux/debugobjects.h>
46 #include <linux/sched.h>
47 #include <linux/sched/sysctl.h>
48 #include <linux/timer.h>
50 #include <asm/uaccess.h>
52 #include <trace/events/timer.h>
57 * There are more clockids then hrtimer bases. Thus, we index
58 * into the timer bases by the hrtimer_base_type enum. When trying
59 * to reach a base using a clockid, hrtimer_clockid_to_base()
60 * is used to convert from clockid to the proper hrtimer_base_type.
62 DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
68 .index = HRTIMER_BASE_MONOTONIC,
69 .clockid = CLOCK_MONOTONIC,
70 .get_time = &ktime_get,
71 .resolution = KTIME_LOW_RES,
74 .index = HRTIMER_BASE_REALTIME,
75 .clockid = CLOCK_REALTIME,
76 .get_time = &ktime_get_real,
77 .resolution = KTIME_LOW_RES,
80 .index = HRTIMER_BASE_BOOTTIME,
81 .clockid = CLOCK_BOOTTIME,
82 .get_time = &ktime_get_boottime,
83 .resolution = KTIME_LOW_RES,
88 static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
89 [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
90 [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
91 [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
94 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
96 return hrtimer_clock_to_base_table[clock_id];
101 * Get the coarse grained time at the softirq based on xtime and
104 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
106 ktime_t xtim, mono, boot;
107 struct timespec xts, tom, slp;
109 get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
111 xtim = timespec_to_ktime(xts);
112 mono = ktime_add(xtim, timespec_to_ktime(tom));
113 boot = ktime_add(mono, timespec_to_ktime(slp));
114 base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
115 base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
116 base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
120 * Functions and macros which are different for UP/SMP systems are kept in a
126 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
127 * means that all timers which are tied to this base via timer->base are
128 * locked, and the base itself is locked too.
130 * So __run_timers/migrate_timers can safely modify all timers which could
131 * be found on the lists/queues.
133 * When the timer's base is locked, and the timer removed from list, it is
134 * possible to set timer->base = NULL and drop the lock: the timer remains
138 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
139 unsigned long *flags)
141 struct hrtimer_clock_base *base;
145 if (likely(base != NULL)) {
146 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
147 if (likely(base == timer->base))
149 /* The timer has migrated to another CPU: */
150 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
158 * Get the preferred target CPU for NOHZ
160 static int hrtimer_get_target(int this_cpu, int pinned)
163 if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
164 return get_nohz_timer_target();
170 * With HIGHRES=y we do not migrate the timer when it is expiring
171 * before the next event on the target cpu because we cannot reprogram
172 * the target cpu hardware and we would cause it to fire late.
174 * Called with cpu_base->lock of target cpu held.
177 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
179 #ifdef CONFIG_HIGH_RES_TIMERS
182 if (!new_base->cpu_base->hres_active)
185 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
186 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
193 * Switch the timer base to the current CPU when possible.
195 static inline struct hrtimer_clock_base *
196 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;
201 int this_cpu = smp_processor_id();
202 int cpu = hrtimer_get_target(this_cpu, pinned);
203 int basenum = base->index;
206 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
207 new_base = &new_cpu_base->clock_base[basenum];
209 if (base != new_base) {
211 * We are trying to move timer to new_base.
212 * However we can't change timer's base while it is running,
213 * so we keep it on the same CPU. No hassle vs. reprogramming
214 * the event source in the high resolution case. The softirq
215 * code will take care of this when the timer function has
216 * completed. There is no conflict as we hold the lock until
217 * the timer is enqueued.
219 if (unlikely(hrtimer_callback_running(timer)))
222 /* See the comment in lock_timer_base() */
224 raw_spin_unlock(&base->cpu_base->lock);
225 raw_spin_lock(&new_base->cpu_base->lock);
227 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
229 raw_spin_unlock(&new_base->cpu_base->lock);
230 raw_spin_lock(&base->cpu_base->lock);
234 timer->base = new_base;
239 #else /* CONFIG_SMP */
241 static inline struct hrtimer_clock_base *
242 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
244 struct hrtimer_clock_base *base = timer->base;
246 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
251 # define switch_hrtimer_base(t, b, p) (b)
253 #endif /* !CONFIG_SMP */
256 * Functions for the union type storage format of ktime_t which are
257 * too large for inlining:
259 #if BITS_PER_LONG < 64
260 # ifndef CONFIG_KTIME_SCALAR
262 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
264 * @nsec: the scalar nsec value to add
266 * Returns the sum of kt and nsec in ktime_t format
268 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
272 if (likely(nsec < NSEC_PER_SEC)) {
275 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
277 tmp = ktime_set((long)nsec, rem);
280 return ktime_add(kt, tmp);
283 EXPORT_SYMBOL_GPL(ktime_add_ns);
286 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
288 * @nsec: the scalar nsec value to subtract
290 * Returns the subtraction of @nsec from @kt in ktime_t format
292 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
296 if (likely(nsec < NSEC_PER_SEC)) {
299 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
301 tmp = ktime_set((long)nsec, rem);
304 return ktime_sub(kt, tmp);
307 EXPORT_SYMBOL_GPL(ktime_sub_ns);
308 # endif /* !CONFIG_KTIME_SCALAR */
311 * Divide a ktime value by a nanosecond value
313 u64 ktime_divns(const ktime_t kt, s64 div)
318 dclc = ktime_to_ns(kt);
319 /* Make sure the divisor is less than 2^32: */
325 do_div(dclc, (unsigned long) div);
329 #endif /* BITS_PER_LONG >= 64 */
332 * Add two ktime values and do a safety check for overflow:
334 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
336 ktime_t res = ktime_add(lhs, rhs);
339 * We use KTIME_SEC_MAX here, the maximum timeout which we can
340 * return to user space in a timespec:
342 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
343 res = ktime_set(KTIME_SEC_MAX, 0);
348 EXPORT_SYMBOL_GPL(ktime_add_safe);
350 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
352 static struct debug_obj_descr hrtimer_debug_descr;
354 static void *hrtimer_debug_hint(void *addr)
356 return ((struct hrtimer *) addr)->function;
360 * fixup_init is called when:
361 * - an active object is initialized
363 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
365 struct hrtimer *timer = addr;
368 case ODEBUG_STATE_ACTIVE:
369 hrtimer_cancel(timer);
370 debug_object_init(timer, &hrtimer_debug_descr);
378 * fixup_activate is called when:
379 * - an active object is activated
380 * - an unknown object is activated (might be a statically initialized object)
382 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
386 case ODEBUG_STATE_NOTAVAILABLE:
390 case ODEBUG_STATE_ACTIVE:
399 * fixup_free is called when:
400 * - an active object is freed
402 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
404 struct hrtimer *timer = addr;
407 case ODEBUG_STATE_ACTIVE:
408 hrtimer_cancel(timer);
409 debug_object_free(timer, &hrtimer_debug_descr);
416 static struct debug_obj_descr hrtimer_debug_descr = {
418 .debug_hint = hrtimer_debug_hint,
419 .fixup_init = hrtimer_fixup_init,
420 .fixup_activate = hrtimer_fixup_activate,
421 .fixup_free = hrtimer_fixup_free,
424 static inline void debug_hrtimer_init(struct hrtimer *timer)
426 debug_object_init(timer, &hrtimer_debug_descr);
429 static inline void debug_hrtimer_activate(struct hrtimer *timer)
431 debug_object_activate(timer, &hrtimer_debug_descr);
434 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
436 debug_object_deactivate(timer, &hrtimer_debug_descr);
439 static inline void debug_hrtimer_free(struct hrtimer *timer)
441 debug_object_free(timer, &hrtimer_debug_descr);
444 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
445 enum hrtimer_mode mode);
447 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
448 enum hrtimer_mode mode)
450 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
451 __hrtimer_init(timer, clock_id, mode);
453 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
455 void destroy_hrtimer_on_stack(struct hrtimer *timer)
457 debug_object_free(timer, &hrtimer_debug_descr);
461 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
462 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
463 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
467 debug_init(struct hrtimer *timer, clockid_t clockid,
468 enum hrtimer_mode mode)
470 debug_hrtimer_init(timer);
471 trace_hrtimer_init(timer, clockid, mode);
474 static inline void debug_activate(struct hrtimer *timer)
476 debug_hrtimer_activate(timer);
477 trace_hrtimer_start(timer);
480 static inline void debug_deactivate(struct hrtimer *timer)
482 debug_hrtimer_deactivate(timer);
483 trace_hrtimer_cancel(timer);
486 /* High resolution timer related functions */
487 #ifdef CONFIG_HIGH_RES_TIMERS
490 * High resolution timer enabled ?
492 static int hrtimer_hres_enabled __read_mostly = 1;
495 * Enable / Disable high resolution mode
497 static int __init setup_hrtimer_hres(char *str)
499 if (!strcmp(str, "off"))
500 hrtimer_hres_enabled = 0;
501 else if (!strcmp(str, "on"))
502 hrtimer_hres_enabled = 1;
508 __setup("highres=", setup_hrtimer_hres);
511 * hrtimer_high_res_enabled - query, if the highres mode is enabled
513 static inline int hrtimer_is_hres_enabled(void)
515 return hrtimer_hres_enabled;
519 * Is the high resolution mode active ?
521 static inline int hrtimer_hres_active(void)
523 return __this_cpu_read(hrtimer_bases.hres_active);
527 * Reprogram the event source with checking both queues for the
529 * Called with interrupts disabled and base->lock held
532 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
535 struct hrtimer_clock_base *base = cpu_base->clock_base;
536 ktime_t expires, expires_next;
538 expires_next.tv64 = KTIME_MAX;
540 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
541 struct hrtimer *timer;
542 struct timerqueue_node *next;
544 next = timerqueue_getnext(&base->active);
547 timer = container_of(next, struct hrtimer, node);
549 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
551 * clock_was_set() has changed base->offset so the
552 * result might be negative. Fix it up to prevent a
553 * false positive in clockevents_program_event()
555 if (expires.tv64 < 0)
557 if (expires.tv64 < expires_next.tv64)
558 expires_next = expires;
561 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
564 cpu_base->expires_next.tv64 = expires_next.tv64;
566 if (cpu_base->expires_next.tv64 != KTIME_MAX)
567 tick_program_event(cpu_base->expires_next, 1);
571 * Shared reprogramming for clock_realtime and clock_monotonic
573 * When a timer is enqueued and expires earlier than the already enqueued
574 * timers, we have to check, whether it expires earlier than the timer for
575 * which the clock event device was armed.
577 * Called with interrupts disabled and base->cpu_base.lock held
579 static int hrtimer_reprogram(struct hrtimer *timer,
580 struct hrtimer_clock_base *base)
582 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
583 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
586 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
589 * When the callback is running, we do not reprogram the clock event
590 * device. The timer callback is either running on a different CPU or
591 * the callback is executed in the hrtimer_interrupt context. The
592 * reprogramming is handled either by the softirq, which called the
593 * callback or at the end of the hrtimer_interrupt.
595 if (hrtimer_callback_running(timer))
599 * CLOCK_REALTIME timer might be requested with an absolute
600 * expiry time which is less than base->offset. Nothing wrong
601 * about that, just avoid to call into the tick code, which
602 * has now objections against negative expiry values.
604 if (expires.tv64 < 0)
607 if (expires.tv64 >= cpu_base->expires_next.tv64)
611 * If a hang was detected in the last timer interrupt then we
612 * do not schedule a timer which is earlier than the expiry
613 * which we enforced in the hang detection. We want the system
616 if (cpu_base->hang_detected)
620 * Clockevents returns -ETIME, when the event was in the past.
622 res = tick_program_event(expires, 0);
623 if (!IS_ERR_VALUE(res))
624 cpu_base->expires_next = expires;
629 * Initialize the high resolution related parts of cpu_base
631 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
633 base->expires_next.tv64 = KTIME_MAX;
634 base->hres_active = 0;
638 * When High resolution timers are active, try to reprogram. Note, that in case
639 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
640 * check happens. The timer gets enqueued into the rbtree. The reprogramming
641 * and expiry check is done in the hrtimer_interrupt or in the softirq.
643 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
644 struct hrtimer_clock_base *base,
647 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
649 raw_spin_unlock(&base->cpu_base->lock);
650 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
651 raw_spin_lock(&base->cpu_base->lock);
653 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
661 static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
663 ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
664 ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
666 return ktime_get_update_offsets(offs_real, offs_boot);
670 * Retrigger next event is called after clock was set
672 * Called with interrupts disabled via on_each_cpu()
674 static void retrigger_next_event(void *arg)
676 struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
678 if (!hrtimer_hres_active())
681 raw_spin_lock(&base->lock);
682 hrtimer_update_base(base);
683 hrtimer_force_reprogram(base, 0);
684 raw_spin_unlock(&base->lock);
688 * Switch to high resolution mode
690 static int hrtimer_switch_to_hres(void)
692 int i, cpu = smp_processor_id();
693 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
696 if (base->hres_active)
699 local_irq_save(flags);
701 if (tick_init_highres()) {
702 local_irq_restore(flags);
703 printk(KERN_WARNING "Could not switch to high resolution "
704 "mode on CPU %d\n", cpu);
707 base->hres_active = 1;
708 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
709 base->clock_base[i].resolution = KTIME_HIGH_RES;
711 tick_setup_sched_timer();
712 /* "Retrigger" the interrupt to get things going */
713 retrigger_next_event(NULL);
714 local_irq_restore(flags);
719 * Called from timekeeping code to reprogramm the hrtimer interrupt
720 * device. If called from the timer interrupt context we defer it to
723 void clock_was_set_delayed(void)
725 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
727 cpu_base->clock_was_set = 1;
728 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
733 static inline int hrtimer_hres_active(void) { return 0; }
734 static inline int hrtimer_is_hres_enabled(void) { return 0; }
735 static inline int hrtimer_switch_to_hres(void) { return 0; }
737 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
738 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
739 struct hrtimer_clock_base *base,
744 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
745 static inline void retrigger_next_event(void *arg) { }
747 #endif /* CONFIG_HIGH_RES_TIMERS */
750 * Clock realtime was set
752 * Change the offset of the realtime clock vs. the monotonic
755 * We might have to reprogram the high resolution timer interrupt. On
756 * SMP we call the architecture specific code to retrigger _all_ high
757 * resolution timer interrupts. On UP we just disable interrupts and
758 * call the high resolution interrupt code.
760 void clock_was_set(void)
762 #ifdef CONFIG_HIGH_RES_TIMERS
763 /* Retrigger the CPU local events everywhere */
764 on_each_cpu(retrigger_next_event, NULL, 1);
766 timerfd_clock_was_set();
770 * During resume we might have to reprogram the high resolution timer
771 * interrupt (on the local CPU):
773 void hrtimers_resume(void)
775 WARN_ONCE(!irqs_disabled(),
776 KERN_INFO "hrtimers_resume() called with IRQs enabled!");
778 retrigger_next_event(NULL);
779 timerfd_clock_was_set();
782 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
784 #ifdef CONFIG_TIMER_STATS
785 if (timer->start_site)
787 timer->start_site = __builtin_return_address(0);
788 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
789 timer->start_pid = current->pid;
793 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
795 #ifdef CONFIG_TIMER_STATS
796 timer->start_site = NULL;
800 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
802 #ifdef CONFIG_TIMER_STATS
803 if (likely(!timer_stats_active))
805 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
806 timer->function, timer->start_comm, 0);
811 * Counterpart to lock_hrtimer_base above:
814 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
816 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
820 * hrtimer_forward - forward the timer expiry
821 * @timer: hrtimer to forward
822 * @now: forward past this time
823 * @interval: the interval to forward
825 * Forward the timer expiry so it will expire in the future.
826 * Returns the number of overruns.
828 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
833 delta = ktime_sub(now, hrtimer_get_expires(timer));
838 if (interval.tv64 < timer->base->resolution.tv64)
839 interval.tv64 = timer->base->resolution.tv64;
841 if (unlikely(delta.tv64 >= interval.tv64)) {
842 s64 incr = ktime_to_ns(interval);
844 orun = ktime_divns(delta, incr);
845 hrtimer_add_expires_ns(timer, incr * orun);
846 if (hrtimer_get_expires_tv64(timer) > now.tv64)
849 * This (and the ktime_add() below) is the
850 * correction for exact:
854 hrtimer_add_expires(timer, interval);
858 EXPORT_SYMBOL_GPL(hrtimer_forward);
861 * enqueue_hrtimer - internal function to (re)start a timer
863 * The timer is inserted in expiry order. Insertion into the
864 * red black tree is O(log(n)). Must hold the base lock.
866 * Returns 1 when the new timer is the leftmost timer in the tree.
868 static int enqueue_hrtimer(struct hrtimer *timer,
869 struct hrtimer_clock_base *base)
871 debug_activate(timer);
873 timerqueue_add(&base->active, &timer->node);
874 base->cpu_base->active_bases |= 1 << base->index;
877 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
878 * state of a possibly running callback.
880 timer->state |= HRTIMER_STATE_ENQUEUED;
882 return (&timer->node == base->active.next);
886 * __remove_hrtimer - internal function to remove a timer
888 * Caller must hold the base lock.
890 * High resolution timer mode reprograms the clock event device when the
891 * timer is the one which expires next. The caller can disable this by setting
892 * reprogram to zero. This is useful, when the context does a reprogramming
893 * anyway (e.g. timer interrupt)
895 static void __remove_hrtimer(struct hrtimer *timer,
896 struct hrtimer_clock_base *base,
897 unsigned long newstate, int reprogram)
899 struct timerqueue_node *next_timer;
900 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
903 next_timer = timerqueue_getnext(&base->active);
904 timerqueue_del(&base->active, &timer->node);
905 if (&timer->node == next_timer) {
906 #ifdef CONFIG_HIGH_RES_TIMERS
907 /* Reprogram the clock event device. if enabled */
908 if (reprogram && hrtimer_hres_active()) {
911 expires = ktime_sub(hrtimer_get_expires(timer),
913 if (base->cpu_base->expires_next.tv64 == expires.tv64)
914 hrtimer_force_reprogram(base->cpu_base, 1);
918 if (!timerqueue_getnext(&base->active))
919 base->cpu_base->active_bases &= ~(1 << base->index);
921 timer->state = newstate;
925 * remove hrtimer, called with base lock held
928 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
930 if (hrtimer_is_queued(timer)) {
935 * Remove the timer and force reprogramming when high
936 * resolution mode is active and the timer is on the current
937 * CPU. If we remove a timer on another CPU, reprogramming is
938 * skipped. The interrupt event on this CPU is fired and
939 * reprogramming happens in the interrupt handler. This is a
940 * rare case and less expensive than a smp call.
942 debug_deactivate(timer);
943 timer_stats_hrtimer_clear_start_info(timer);
944 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
946 * We must preserve the CALLBACK state flag here,
947 * otherwise we could move the timer base in
948 * switch_hrtimer_base.
950 state = timer->state & HRTIMER_STATE_CALLBACK;
951 __remove_hrtimer(timer, base, state, reprogram);
957 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
958 unsigned long delta_ns, const enum hrtimer_mode mode,
961 struct hrtimer_clock_base *base, *new_base;
965 base = lock_hrtimer_base(timer, &flags);
967 /* Remove an active timer from the queue: */
968 ret = remove_hrtimer(timer, base);
970 /* Switch the timer base, if necessary: */
971 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
973 if (mode & HRTIMER_MODE_REL) {
974 tim = ktime_add_safe(tim, new_base->get_time());
976 * CONFIG_TIME_LOW_RES is a temporary way for architectures
977 * to signal that they simply return xtime in
978 * do_gettimeoffset(). In this case we want to round up by
979 * resolution when starting a relative timer, to avoid short
980 * timeouts. This will go away with the GTOD framework.
982 #ifdef CONFIG_TIME_LOW_RES
983 tim = ktime_add_safe(tim, base->resolution);
987 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
989 timer_stats_hrtimer_set_start_info(timer);
991 leftmost = enqueue_hrtimer(timer, new_base);
994 * Only allow reprogramming if the new base is on this CPU.
995 * (it might still be on another CPU if the timer was pending)
997 * XXX send_remote_softirq() ?
999 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
1000 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
1002 unlock_hrtimer_base(timer, &flags);
1008 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
1009 * @timer: the timer to be added
1011 * @delta_ns: "slack" range for the timer
1012 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1016 * 1 when the timer was active
1018 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1019 unsigned long delta_ns, const enum hrtimer_mode mode)
1021 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1023 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1026 * hrtimer_start - (re)start an hrtimer on the current CPU
1027 * @timer: the timer to be added
1029 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1033 * 1 when the timer was active
1036 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1038 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1040 EXPORT_SYMBOL_GPL(hrtimer_start);
1044 * hrtimer_try_to_cancel - try to deactivate a timer
1045 * @timer: hrtimer to stop
1048 * 0 when the timer was not active
1049 * 1 when the timer was active
1050 * -1 when the timer is currently excuting the callback function and
1053 int hrtimer_try_to_cancel(struct hrtimer *timer)
1055 struct hrtimer_clock_base *base;
1056 unsigned long flags;
1059 base = lock_hrtimer_base(timer, &flags);
1061 if (!hrtimer_callback_running(timer))
1062 ret = remove_hrtimer(timer, base);
1064 unlock_hrtimer_base(timer, &flags);
1069 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1072 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1073 * @timer: the timer to be cancelled
1076 * 0 when the timer was not active
1077 * 1 when the timer was active
1079 int hrtimer_cancel(struct hrtimer *timer)
1082 int ret = hrtimer_try_to_cancel(timer);
1089 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1092 * hrtimer_get_remaining - get remaining time for the timer
1093 * @timer: the timer to read
1095 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1097 unsigned long flags;
1100 lock_hrtimer_base(timer, &flags);
1101 rem = hrtimer_expires_remaining(timer);
1102 unlock_hrtimer_base(timer, &flags);
1106 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1110 * hrtimer_get_next_event - get the time until next expiry event
1112 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1115 ktime_t hrtimer_get_next_event(void)
1117 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1118 struct hrtimer_clock_base *base = cpu_base->clock_base;
1119 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1120 unsigned long flags;
1123 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1125 if (!hrtimer_hres_active()) {
1126 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1127 struct hrtimer *timer;
1128 struct timerqueue_node *next;
1130 next = timerqueue_getnext(&base->active);
1134 timer = container_of(next, struct hrtimer, node);
1135 delta.tv64 = hrtimer_get_expires_tv64(timer);
1136 delta = ktime_sub(delta, base->get_time());
1137 if (delta.tv64 < mindelta.tv64)
1138 mindelta.tv64 = delta.tv64;
1142 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1144 if (mindelta.tv64 < 0)
1150 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1151 enum hrtimer_mode mode)
1153 struct hrtimer_cpu_base *cpu_base;
1156 memset(timer, 0, sizeof(struct hrtimer));
1158 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1160 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1161 clock_id = CLOCK_MONOTONIC;
1163 base = hrtimer_clockid_to_base(clock_id);
1164 timer->base = &cpu_base->clock_base[base];
1165 timerqueue_init(&timer->node);
1167 #ifdef CONFIG_TIMER_STATS
1168 timer->start_site = NULL;
1169 timer->start_pid = -1;
1170 memset(timer->start_comm, 0, TASK_COMM_LEN);
1175 * hrtimer_init - initialize a timer to the given clock
1176 * @timer: the timer to be initialized
1177 * @clock_id: the clock to be used
1178 * @mode: timer mode abs/rel
1180 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1181 enum hrtimer_mode mode)
1183 debug_init(timer, clock_id, mode);
1184 __hrtimer_init(timer, clock_id, mode);
1186 EXPORT_SYMBOL_GPL(hrtimer_init);
1189 * hrtimer_get_res - get the timer resolution for a clock
1190 * @which_clock: which clock to query
1191 * @tp: pointer to timespec variable to store the resolution
1193 * Store the resolution of the clock selected by @which_clock in the
1194 * variable pointed to by @tp.
1196 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1198 struct hrtimer_cpu_base *cpu_base;
1199 int base = hrtimer_clockid_to_base(which_clock);
1201 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1202 *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
1206 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1208 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1210 struct hrtimer_clock_base *base = timer->base;
1211 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1212 enum hrtimer_restart (*fn)(struct hrtimer *);
1215 WARN_ON(!irqs_disabled());
1217 debug_deactivate(timer);
1218 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1219 timer_stats_account_hrtimer(timer);
1220 fn = timer->function;
1223 * Because we run timers from hardirq context, there is no chance
1224 * they get migrated to another cpu, therefore its safe to unlock
1227 raw_spin_unlock(&cpu_base->lock);
1228 trace_hrtimer_expire_entry(timer, now);
1229 restart = fn(timer);
1230 trace_hrtimer_expire_exit(timer);
1231 raw_spin_lock(&cpu_base->lock);
1234 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1235 * we do not reprogramm the event hardware. Happens either in
1236 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1238 if (restart != HRTIMER_NORESTART) {
1239 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1240 enqueue_hrtimer(timer, base);
1243 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1245 timer->state &= ~HRTIMER_STATE_CALLBACK;
1248 #ifdef CONFIG_HIGH_RES_TIMERS
1251 * High resolution timer interrupt
1252 * Called with interrupts disabled
1254 void hrtimer_interrupt(struct clock_event_device *dev)
1256 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1257 ktime_t expires_next, now, entry_time, delta;
1260 BUG_ON(!cpu_base->hres_active);
1261 cpu_base->nr_events++;
1262 dev->next_event.tv64 = KTIME_MAX;
1264 raw_spin_lock(&cpu_base->lock);
1265 entry_time = now = hrtimer_update_base(cpu_base);
1267 expires_next.tv64 = KTIME_MAX;
1269 * We set expires_next to KTIME_MAX here with cpu_base->lock
1270 * held to prevent that a timer is enqueued in our queue via
1271 * the migration code. This does not affect enqueueing of
1272 * timers which run their callback and need to be requeued on
1275 cpu_base->expires_next.tv64 = KTIME_MAX;
1277 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1278 struct hrtimer_clock_base *base;
1279 struct timerqueue_node *node;
1282 if (!(cpu_base->active_bases & (1 << i)))
1285 base = cpu_base->clock_base + i;
1286 basenow = ktime_add(now, base->offset);
1288 while ((node = timerqueue_getnext(&base->active))) {
1289 struct hrtimer *timer;
1291 timer = container_of(node, struct hrtimer, node);
1294 * The immediate goal for using the softexpires is
1295 * minimizing wakeups, not running timers at the
1296 * earliest interrupt after their soft expiration.
1297 * This allows us to avoid using a Priority Search
1298 * Tree, which can answer a stabbing querry for
1299 * overlapping intervals and instead use the simple
1300 * BST we already have.
1301 * We don't add extra wakeups by delaying timers that
1302 * are right-of a not yet expired timer, because that
1303 * timer will have to trigger a wakeup anyway.
1306 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1309 expires = ktime_sub(hrtimer_get_expires(timer),
1311 if (expires.tv64 < expires_next.tv64)
1312 expires_next = expires;
1316 __run_hrtimer(timer, &basenow);
1321 * Store the new expiry value so the migration code can verify
1324 cpu_base->expires_next = expires_next;
1325 raw_spin_unlock(&cpu_base->lock);
1327 /* Reprogramming necessary ? */
1328 if (expires_next.tv64 == KTIME_MAX ||
1329 !tick_program_event(expires_next, 0)) {
1330 cpu_base->hang_detected = 0;
1335 * The next timer was already expired due to:
1337 * - long lasting callbacks
1338 * - being scheduled away when running in a VM
1340 * We need to prevent that we loop forever in the hrtimer
1341 * interrupt routine. We give it 3 attempts to avoid
1342 * overreacting on some spurious event.
1344 * Acquire base lock for updating the offsets and retrieving
1347 raw_spin_lock(&cpu_base->lock);
1348 now = hrtimer_update_base(cpu_base);
1349 cpu_base->nr_retries++;
1353 * Give the system a chance to do something else than looping
1354 * here. We stored the entry time, so we know exactly how long
1355 * we spent here. We schedule the next event this amount of
1358 cpu_base->nr_hangs++;
1359 cpu_base->hang_detected = 1;
1360 raw_spin_unlock(&cpu_base->lock);
1361 delta = ktime_sub(now, entry_time);
1362 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1363 cpu_base->max_hang_time = delta;
1365 * Limit it to a sensible value as we enforce a longer
1366 * delay. Give the CPU at least 100ms to catch up.
1368 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1369 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1371 expires_next = ktime_add(now, delta);
1372 tick_program_event(expires_next, 1);
1373 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1374 ktime_to_ns(delta));
1378 * local version of hrtimer_peek_ahead_timers() called with interrupts
1381 static void __hrtimer_peek_ahead_timers(void)
1383 struct tick_device *td;
1385 if (!hrtimer_hres_active())
1388 td = &__get_cpu_var(tick_cpu_device);
1389 if (td && td->evtdev)
1390 hrtimer_interrupt(td->evtdev);
1394 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1396 * hrtimer_peek_ahead_timers will peek at the timer queue of
1397 * the current cpu and check if there are any timers for which
1398 * the soft expires time has passed. If any such timers exist,
1399 * they are run immediately and then removed from the timer queue.
1402 void hrtimer_peek_ahead_timers(void)
1404 unsigned long flags;
1406 local_irq_save(flags);
1407 __hrtimer_peek_ahead_timers();
1408 local_irq_restore(flags);
1411 static void run_hrtimer_softirq(struct softirq_action *h)
1413 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1415 if (cpu_base->clock_was_set) {
1416 cpu_base->clock_was_set = 0;
1420 hrtimer_peek_ahead_timers();
1423 #else /* CONFIG_HIGH_RES_TIMERS */
1425 static inline void __hrtimer_peek_ahead_timers(void) { }
1427 #endif /* !CONFIG_HIGH_RES_TIMERS */
1430 * Called from timer softirq every jiffy, expire hrtimers:
1432 * For HRT its the fall back code to run the softirq in the timer
1433 * softirq context in case the hrtimer initialization failed or has
1434 * not been done yet.
1436 void hrtimer_run_pending(void)
1438 if (hrtimer_hres_active())
1442 * This _is_ ugly: We have to check in the softirq context,
1443 * whether we can switch to highres and / or nohz mode. The
1444 * clocksource switch happens in the timer interrupt with
1445 * xtime_lock held. Notification from there only sets the
1446 * check bit in the tick_oneshot code, otherwise we might
1447 * deadlock vs. xtime_lock.
1449 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1450 hrtimer_switch_to_hres();
1454 * Called from hardirq context every jiffy
1456 void hrtimer_run_queues(void)
1458 struct timerqueue_node *node;
1459 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1460 struct hrtimer_clock_base *base;
1461 int index, gettime = 1;
1463 if (hrtimer_hres_active())
1466 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1467 base = &cpu_base->clock_base[index];
1468 if (!timerqueue_getnext(&base->active))
1472 hrtimer_get_softirq_time(cpu_base);
1476 raw_spin_lock(&cpu_base->lock);
1478 while ((node = timerqueue_getnext(&base->active))) {
1479 struct hrtimer *timer;
1481 timer = container_of(node, struct hrtimer, node);
1482 if (base->softirq_time.tv64 <=
1483 hrtimer_get_expires_tv64(timer))
1486 __run_hrtimer(timer, &base->softirq_time);
1488 raw_spin_unlock(&cpu_base->lock);
1493 * Sleep related functions:
1495 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1497 struct hrtimer_sleeper *t =
1498 container_of(timer, struct hrtimer_sleeper, timer);
1499 struct task_struct *task = t->task;
1503 wake_up_process(task);
1505 return HRTIMER_NORESTART;
1508 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1510 sl->timer.function = hrtimer_wakeup;
1513 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1515 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1517 hrtimer_init_sleeper(t, current);
1520 set_current_state(TASK_INTERRUPTIBLE);
1521 hrtimer_start_expires(&t->timer, mode);
1522 if (!hrtimer_active(&t->timer))
1525 if (likely(t->task))
1528 hrtimer_cancel(&t->timer);
1529 mode = HRTIMER_MODE_ABS;
1531 } while (t->task && !signal_pending(current));
1533 __set_current_state(TASK_RUNNING);
1535 return t->task == NULL;
1538 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1540 struct timespec rmt;
1543 rem = hrtimer_expires_remaining(timer);
1546 rmt = ktime_to_timespec(rem);
1548 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1554 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1556 struct hrtimer_sleeper t;
1557 struct timespec __user *rmtp;
1560 hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
1562 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1564 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1567 rmtp = restart->nanosleep.rmtp;
1569 ret = update_rmtp(&t.timer, rmtp);
1574 /* The other values in restart are already filled in */
1575 ret = -ERESTART_RESTARTBLOCK;
1577 destroy_hrtimer_on_stack(&t.timer);
1581 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1582 const enum hrtimer_mode mode, const clockid_t clockid)
1584 struct restart_block *restart;
1585 struct hrtimer_sleeper t;
1587 unsigned long slack;
1589 slack = current->timer_slack_ns;
1590 if (rt_task(current))
1593 hrtimer_init_on_stack(&t.timer, clockid, mode);
1594 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1595 if (do_nanosleep(&t, mode))
1598 /* Absolute timers do not update the rmtp value and restart: */
1599 if (mode == HRTIMER_MODE_ABS) {
1600 ret = -ERESTARTNOHAND;
1605 ret = update_rmtp(&t.timer, rmtp);
1610 restart = ¤t_thread_info()->restart_block;
1611 restart->fn = hrtimer_nanosleep_restart;
1612 restart->nanosleep.clockid = t.timer.base->clockid;
1613 restart->nanosleep.rmtp = rmtp;
1614 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1616 ret = -ERESTART_RESTARTBLOCK;
1618 destroy_hrtimer_on_stack(&t.timer);
1622 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1623 struct timespec __user *, rmtp)
1627 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1630 if (!timespec_valid(&tu))
1633 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1637 * Functions related to boot-time initialization:
1639 static void __cpuinit init_hrtimers_cpu(int cpu)
1641 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1644 raw_spin_lock_init(&cpu_base->lock);
1646 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1647 cpu_base->clock_base[i].cpu_base = cpu_base;
1648 timerqueue_init_head(&cpu_base->clock_base[i].active);
1651 hrtimer_init_hres(cpu_base);
1654 #ifdef CONFIG_HOTPLUG_CPU
1656 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1657 struct hrtimer_clock_base *new_base)
1659 struct hrtimer *timer;
1660 struct timerqueue_node *node;
1662 while ((node = timerqueue_getnext(&old_base->active))) {
1663 timer = container_of(node, struct hrtimer, node);
1664 BUG_ON(hrtimer_callback_running(timer));
1665 debug_deactivate(timer);
1668 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1669 * timer could be seen as !active and just vanish away
1670 * under us on another CPU
1672 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1673 timer->base = new_base;
1675 * Enqueue the timers on the new cpu. This does not
1676 * reprogram the event device in case the timer
1677 * expires before the earliest on this CPU, but we run
1678 * hrtimer_interrupt after we migrated everything to
1679 * sort out already expired timers and reprogram the
1682 enqueue_hrtimer(timer, new_base);
1684 /* Clear the migration state bit */
1685 timer->state &= ~HRTIMER_STATE_MIGRATE;
1689 static void migrate_hrtimers(int scpu)
1691 struct hrtimer_cpu_base *old_base, *new_base;
1694 BUG_ON(cpu_online(scpu));
1695 tick_cancel_sched_timer(scpu);
1697 local_irq_disable();
1698 old_base = &per_cpu(hrtimer_bases, scpu);
1699 new_base = &__get_cpu_var(hrtimer_bases);
1701 * The caller is globally serialized and nobody else
1702 * takes two locks at once, deadlock is not possible.
1704 raw_spin_lock(&new_base->lock);
1705 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1707 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1708 migrate_hrtimer_list(&old_base->clock_base[i],
1709 &new_base->clock_base[i]);
1712 raw_spin_unlock(&old_base->lock);
1713 raw_spin_unlock(&new_base->lock);
1715 /* Check, if we got expired work to do */
1716 __hrtimer_peek_ahead_timers();
1720 #endif /* CONFIG_HOTPLUG_CPU */
1722 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1723 unsigned long action, void *hcpu)
1725 int scpu = (long)hcpu;
1729 case CPU_UP_PREPARE:
1730 case CPU_UP_PREPARE_FROZEN:
1731 init_hrtimers_cpu(scpu);
1734 #ifdef CONFIG_HOTPLUG_CPU
1736 case CPU_DYING_FROZEN:
1737 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1740 case CPU_DEAD_FROZEN:
1742 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1743 migrate_hrtimers(scpu);
1755 static struct notifier_block __cpuinitdata hrtimers_nb = {
1756 .notifier_call = hrtimer_cpu_notify,
1759 void __init hrtimers_init(void)
1761 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1762 (void *)(long)smp_processor_id());
1763 register_cpu_notifier(&hrtimers_nb);
1764 #ifdef CONFIG_HIGH_RES_TIMERS
1765 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1770 * schedule_hrtimeout_range_clock - sleep until timeout
1771 * @expires: timeout value (ktime_t)
1772 * @delta: slack in expires timeout (ktime_t)
1773 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1774 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1777 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1778 const enum hrtimer_mode mode, int clock)
1780 struct hrtimer_sleeper t;
1783 * Optimize when a zero timeout value is given. It does not
1784 * matter whether this is an absolute or a relative time.
1786 if (expires && !expires->tv64) {
1787 __set_current_state(TASK_RUNNING);
1792 * A NULL parameter means "infinite"
1796 __set_current_state(TASK_RUNNING);
1800 hrtimer_init_on_stack(&t.timer, clock, mode);
1801 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1803 hrtimer_init_sleeper(&t, current);
1805 hrtimer_start_expires(&t.timer, mode);
1806 if (!hrtimer_active(&t.timer))
1812 hrtimer_cancel(&t.timer);
1813 destroy_hrtimer_on_stack(&t.timer);
1815 __set_current_state(TASK_RUNNING);
1817 return !t.task ? 0 : -EINTR;
1821 * schedule_hrtimeout_range - sleep until timeout
1822 * @expires: timeout value (ktime_t)
1823 * @delta: slack in expires timeout (ktime_t)
1824 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1826 * Make the current task sleep until the given expiry time has
1827 * elapsed. The routine will return immediately unless
1828 * the current task state has been set (see set_current_state()).
1830 * The @delta argument gives the kernel the freedom to schedule the
1831 * actual wakeup to a time that is both power and performance friendly.
1832 * The kernel give the normal best effort behavior for "@expires+@delta",
1833 * but may decide to fire the timer earlier, but no earlier than @expires.
1835 * You can set the task state as follows -
1837 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1838 * pass before the routine returns.
1840 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1841 * delivered to the current task.
1843 * The current task state is guaranteed to be TASK_RUNNING when this
1846 * Returns 0 when the timer has expired otherwise -EINTR
1848 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1849 const enum hrtimer_mode mode)
1851 return schedule_hrtimeout_range_clock(expires, delta, mode,
1854 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1857 * schedule_hrtimeout - sleep until timeout
1858 * @expires: timeout value (ktime_t)
1859 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1861 * Make the current task sleep until the given expiry time has
1862 * elapsed. The routine will return immediately unless
1863 * the current task state has been set (see set_current_state()).
1865 * You can set the task state as follows -
1867 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1868 * pass before the routine returns.
1870 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1871 * delivered to the current task.
1873 * The current task state is guaranteed to be TASK_RUNNING when this
1876 * Returns 0 when the timer has expired otherwise -EINTR
1878 int __sched schedule_hrtimeout(ktime_t *expires,
1879 const enum hrtimer_mode mode)
1881 return schedule_hrtimeout_range(expires, 0, mode);
1883 EXPORT_SYMBOL_GPL(schedule_hrtimeout);