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/timer.h>
49 #include <asm/uaccess.h>
51 #include <trace/events/timer.h>
56 * There are more clockids then hrtimer bases. Thus, we index
57 * into the timer bases by the hrtimer_base_type enum. When trying
58 * to reach a base using a clockid, hrtimer_clockid_to_base()
59 * is used to convert from clockid to the proper hrtimer_base_type.
61 DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
67 .index = HRTIMER_BASE_MONOTONIC,
68 .clockid = CLOCK_MONOTONIC,
69 .get_time = &ktime_get,
70 .resolution = KTIME_LOW_RES,
73 .index = HRTIMER_BASE_REALTIME,
74 .clockid = CLOCK_REALTIME,
75 .get_time = &ktime_get_real,
76 .resolution = KTIME_LOW_RES,
79 .index = HRTIMER_BASE_BOOTTIME,
80 .clockid = CLOCK_BOOTTIME,
81 .get_time = &ktime_get_boottime,
82 .resolution = KTIME_LOW_RES,
87 static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
88 [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
89 [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
90 [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
93 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
95 return hrtimer_clock_to_base_table[clock_id];
100 * Get the coarse grained time at the softirq based on xtime and
103 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
105 ktime_t xtim, mono, boot;
106 struct timespec xts, tom, slp;
108 get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
110 xtim = timespec_to_ktime(xts);
111 mono = ktime_add(xtim, timespec_to_ktime(tom));
112 boot = ktime_add(mono, timespec_to_ktime(slp));
113 base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
114 base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
115 base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
119 * Functions and macros which are different for UP/SMP systems are kept in a
125 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
126 * means that all timers which are tied to this base via timer->base are
127 * locked, and the base itself is locked too.
129 * So __run_timers/migrate_timers can safely modify all timers which could
130 * be found on the lists/queues.
132 * When the timer's base is locked, and the timer removed from list, it is
133 * possible to set timer->base = NULL and drop the lock: the timer remains
137 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
138 unsigned long *flags)
140 struct hrtimer_clock_base *base;
144 if (likely(base != NULL)) {
145 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
146 if (likely(base == timer->base))
148 /* The timer has migrated to another CPU: */
149 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
157 * Get the preferred target CPU for NOHZ
159 static int hrtimer_get_target(int this_cpu, int pinned)
162 if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
163 return get_nohz_timer_target();
169 * With HIGHRES=y we do not migrate the timer when it is expiring
170 * before the next event on the target cpu because we cannot reprogram
171 * the target cpu hardware and we would cause it to fire late.
173 * Called with cpu_base->lock of target cpu held.
176 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
178 #ifdef CONFIG_HIGH_RES_TIMERS
181 if (!new_base->cpu_base->hres_active)
184 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
185 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
192 * Switch the timer base to the current CPU when possible.
194 static inline struct hrtimer_clock_base *
195 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
198 struct hrtimer_clock_base *new_base;
199 struct hrtimer_cpu_base *new_cpu_base;
200 int this_cpu = smp_processor_id();
201 int cpu = hrtimer_get_target(this_cpu, pinned);
202 int basenum = base->index;
205 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
206 new_base = &new_cpu_base->clock_base[basenum];
208 if (base != new_base) {
210 * We are trying to move timer to new_base.
211 * However we can't change timer's base while it is running,
212 * so we keep it on the same CPU. No hassle vs. reprogramming
213 * the event source in the high resolution case. The softirq
214 * code will take care of this when the timer function has
215 * completed. There is no conflict as we hold the lock until
216 * the timer is enqueued.
218 if (unlikely(hrtimer_callback_running(timer)))
221 /* See the comment in lock_timer_base() */
223 raw_spin_unlock(&base->cpu_base->lock);
224 raw_spin_lock(&new_base->cpu_base->lock);
226 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
228 raw_spin_unlock(&new_base->cpu_base->lock);
229 raw_spin_lock(&base->cpu_base->lock);
233 timer->base = new_base;
238 #else /* CONFIG_SMP */
240 static inline struct hrtimer_clock_base *
241 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
243 struct hrtimer_clock_base *base = timer->base;
245 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
250 # define switch_hrtimer_base(t, b, p) (b)
252 #endif /* !CONFIG_SMP */
255 * Functions for the union type storage format of ktime_t which are
256 * too large for inlining:
258 #if BITS_PER_LONG < 64
259 # ifndef CONFIG_KTIME_SCALAR
261 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
263 * @nsec: the scalar nsec value to add
265 * Returns the sum of kt and nsec in ktime_t format
267 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
271 if (likely(nsec < NSEC_PER_SEC)) {
274 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
276 tmp = ktime_set((long)nsec, rem);
279 return ktime_add(kt, tmp);
282 EXPORT_SYMBOL_GPL(ktime_add_ns);
285 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
287 * @nsec: the scalar nsec value to subtract
289 * Returns the subtraction of @nsec from @kt in ktime_t format
291 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
295 if (likely(nsec < NSEC_PER_SEC)) {
298 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
300 tmp = ktime_set((long)nsec, rem);
303 return ktime_sub(kt, tmp);
306 EXPORT_SYMBOL_GPL(ktime_sub_ns);
307 # endif /* !CONFIG_KTIME_SCALAR */
310 * Divide a ktime value by a nanosecond value
312 u64 ktime_divns(const ktime_t kt, s64 div)
317 dclc = ktime_to_ns(kt);
318 /* Make sure the divisor is less than 2^32: */
324 do_div(dclc, (unsigned long) div);
328 #endif /* BITS_PER_LONG >= 64 */
331 * Add two ktime values and do a safety check for overflow:
333 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
335 ktime_t res = ktime_add(lhs, rhs);
338 * We use KTIME_SEC_MAX here, the maximum timeout which we can
339 * return to user space in a timespec:
341 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
342 res = ktime_set(KTIME_SEC_MAX, 0);
347 EXPORT_SYMBOL_GPL(ktime_add_safe);
349 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
351 static struct debug_obj_descr hrtimer_debug_descr;
353 static void *hrtimer_debug_hint(void *addr)
355 return ((struct hrtimer *) addr)->function;
359 * fixup_init is called when:
360 * - an active object is initialized
362 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
364 struct hrtimer *timer = addr;
367 case ODEBUG_STATE_ACTIVE:
368 hrtimer_cancel(timer);
369 debug_object_init(timer, &hrtimer_debug_descr);
377 * fixup_activate is called when:
378 * - an active object is activated
379 * - an unknown object is activated (might be a statically initialized object)
381 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
385 case ODEBUG_STATE_NOTAVAILABLE:
389 case ODEBUG_STATE_ACTIVE:
398 * fixup_free is called when:
399 * - an active object is freed
401 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
403 struct hrtimer *timer = addr;
406 case ODEBUG_STATE_ACTIVE:
407 hrtimer_cancel(timer);
408 debug_object_free(timer, &hrtimer_debug_descr);
415 static struct debug_obj_descr hrtimer_debug_descr = {
417 .debug_hint = hrtimer_debug_hint,
418 .fixup_init = hrtimer_fixup_init,
419 .fixup_activate = hrtimer_fixup_activate,
420 .fixup_free = hrtimer_fixup_free,
423 static inline void debug_hrtimer_init(struct hrtimer *timer)
425 debug_object_init(timer, &hrtimer_debug_descr);
428 static inline void debug_hrtimer_activate(struct hrtimer *timer)
430 debug_object_activate(timer, &hrtimer_debug_descr);
433 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
435 debug_object_deactivate(timer, &hrtimer_debug_descr);
438 static inline void debug_hrtimer_free(struct hrtimer *timer)
440 debug_object_free(timer, &hrtimer_debug_descr);
443 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
444 enum hrtimer_mode mode);
446 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
447 enum hrtimer_mode mode)
449 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
450 __hrtimer_init(timer, clock_id, mode);
452 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
454 void destroy_hrtimer_on_stack(struct hrtimer *timer)
456 debug_object_free(timer, &hrtimer_debug_descr);
460 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
461 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
462 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
466 debug_init(struct hrtimer *timer, clockid_t clockid,
467 enum hrtimer_mode mode)
469 debug_hrtimer_init(timer);
470 trace_hrtimer_init(timer, clockid, mode);
473 static inline void debug_activate(struct hrtimer *timer)
475 debug_hrtimer_activate(timer);
476 trace_hrtimer_start(timer);
479 static inline void debug_deactivate(struct hrtimer *timer)
481 debug_hrtimer_deactivate(timer);
482 trace_hrtimer_cancel(timer);
485 /* High resolution timer related functions */
486 #ifdef CONFIG_HIGH_RES_TIMERS
489 * High resolution timer enabled ?
491 static int hrtimer_hres_enabled __read_mostly = 1;
494 * Enable / Disable high resolution mode
496 static int __init setup_hrtimer_hres(char *str)
498 if (!strcmp(str, "off"))
499 hrtimer_hres_enabled = 0;
500 else if (!strcmp(str, "on"))
501 hrtimer_hres_enabled = 1;
507 __setup("highres=", setup_hrtimer_hres);
510 * hrtimer_high_res_enabled - query, if the highres mode is enabled
512 static inline int hrtimer_is_hres_enabled(void)
514 return hrtimer_hres_enabled;
518 * Is the high resolution mode active ?
520 static inline int hrtimer_hres_active(void)
522 return __this_cpu_read(hrtimer_bases.hres_active);
526 * Reprogram the event source with checking both queues for the
528 * Called with interrupts disabled and base->lock held
531 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
534 struct hrtimer_clock_base *base = cpu_base->clock_base;
535 ktime_t expires, expires_next;
537 expires_next.tv64 = KTIME_MAX;
539 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
540 struct hrtimer *timer;
541 struct timerqueue_node *next;
543 next = timerqueue_getnext(&base->active);
546 timer = container_of(next, struct hrtimer, node);
548 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
550 * clock_was_set() has changed base->offset so the
551 * result might be negative. Fix it up to prevent a
552 * false positive in clockevents_program_event()
554 if (expires.tv64 < 0)
556 if (expires.tv64 < expires_next.tv64)
557 expires_next = expires;
560 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
563 cpu_base->expires_next.tv64 = expires_next.tv64;
565 if (cpu_base->expires_next.tv64 != KTIME_MAX)
566 tick_program_event(cpu_base->expires_next, 1);
570 * Shared reprogramming for clock_realtime and clock_monotonic
572 * When a timer is enqueued and expires earlier than the already enqueued
573 * timers, we have to check, whether it expires earlier than the timer for
574 * which the clock event device was armed.
576 * Called with interrupts disabled and base->cpu_base.lock held
578 static int hrtimer_reprogram(struct hrtimer *timer,
579 struct hrtimer_clock_base *base)
581 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
582 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
585 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
588 * When the callback is running, we do not reprogram the clock event
589 * device. The timer callback is either running on a different CPU or
590 * the callback is executed in the hrtimer_interrupt context. The
591 * reprogramming is handled either by the softirq, which called the
592 * callback or at the end of the hrtimer_interrupt.
594 if (hrtimer_callback_running(timer))
598 * CLOCK_REALTIME timer might be requested with an absolute
599 * expiry time which is less than base->offset. Nothing wrong
600 * about that, just avoid to call into the tick code, which
601 * has now objections against negative expiry values.
603 if (expires.tv64 < 0)
606 if (expires.tv64 >= cpu_base->expires_next.tv64)
610 * If a hang was detected in the last timer interrupt then we
611 * do not schedule a timer which is earlier than the expiry
612 * which we enforced in the hang detection. We want the system
615 if (cpu_base->hang_detected)
619 * Clockevents returns -ETIME, when the event was in the past.
621 res = tick_program_event(expires, 0);
622 if (!IS_ERR_VALUE(res))
623 cpu_base->expires_next = expires;
628 * Initialize the high resolution related parts of cpu_base
630 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
632 base->expires_next.tv64 = KTIME_MAX;
633 base->hres_active = 0;
637 * When High resolution timers are active, try to reprogram. Note, that in case
638 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
639 * check happens. The timer gets enqueued into the rbtree. The reprogramming
640 * and expiry check is done in the hrtimer_interrupt or in the softirq.
642 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
643 struct hrtimer_clock_base *base,
646 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
648 raw_spin_unlock(&base->cpu_base->lock);
649 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
650 raw_spin_lock(&base->cpu_base->lock);
652 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
661 * Retrigger next event is called after clock was set
663 * Called with interrupts disabled via on_each_cpu()
665 static void retrigger_next_event(void *arg)
667 struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
668 struct timespec realtime_offset, xtim, wtm, sleep;
670 if (!hrtimer_hres_active())
673 /* Optimized out for !HIGH_RES */
674 get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep);
675 set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
677 /* Adjust CLOCK_REALTIME offset */
678 raw_spin_lock(&base->lock);
679 base->clock_base[HRTIMER_BASE_REALTIME].offset =
680 timespec_to_ktime(realtime_offset);
681 base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
682 timespec_to_ktime(sleep);
684 hrtimer_force_reprogram(base, 0);
685 raw_spin_unlock(&base->lock);
689 * Switch to high resolution mode
691 static int hrtimer_switch_to_hres(void)
693 int i, cpu = smp_processor_id();
694 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
697 if (base->hres_active)
700 local_irq_save(flags);
702 if (tick_init_highres()) {
703 local_irq_restore(flags);
704 printk(KERN_WARNING "Could not switch to high resolution "
705 "mode on CPU %d\n", cpu);
708 base->hres_active = 1;
709 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
710 base->clock_base[i].resolution = KTIME_HIGH_RES;
712 tick_setup_sched_timer();
714 /* "Retrigger" the interrupt to get things going */
715 retrigger_next_event(NULL);
716 local_irq_restore(flags);
722 static inline int hrtimer_hres_active(void) { return 0; }
723 static inline int hrtimer_is_hres_enabled(void) { return 0; }
724 static inline int hrtimer_switch_to_hres(void) { return 0; }
726 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
727 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
728 struct hrtimer_clock_base *base,
733 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
734 static inline void retrigger_next_event(void *arg) { }
736 #endif /* CONFIG_HIGH_RES_TIMERS */
739 * Clock realtime was set
741 * Change the offset of the realtime clock vs. the monotonic
744 * We might have to reprogram the high resolution timer interrupt. On
745 * SMP we call the architecture specific code to retrigger _all_ high
746 * resolution timer interrupts. On UP we just disable interrupts and
747 * call the high resolution interrupt code.
749 void clock_was_set(void)
751 #ifdef CONFIG_HIGH_RES_TIMERS
752 /* Retrigger the CPU local events everywhere */
753 on_each_cpu(retrigger_next_event, NULL, 1);
755 timerfd_clock_was_set();
759 * During resume we might have to reprogram the high resolution timer
760 * interrupt (on the local CPU):
762 void hrtimers_resume(void)
764 WARN_ONCE(!irqs_disabled(),
765 KERN_INFO "hrtimers_resume() called with IRQs enabled!");
767 retrigger_next_event(NULL);
768 timerfd_clock_was_set();
771 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
773 #ifdef CONFIG_TIMER_STATS
774 if (timer->start_site)
776 timer->start_site = __builtin_return_address(0);
777 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
778 timer->start_pid = current->pid;
782 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
784 #ifdef CONFIG_TIMER_STATS
785 timer->start_site = NULL;
789 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
791 #ifdef CONFIG_TIMER_STATS
792 if (likely(!timer_stats_active))
794 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
795 timer->function, timer->start_comm, 0);
800 * Counterpart to lock_hrtimer_base above:
803 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
805 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
809 * hrtimer_forward - forward the timer expiry
810 * @timer: hrtimer to forward
811 * @now: forward past this time
812 * @interval: the interval to forward
814 * Forward the timer expiry so it will expire in the future.
815 * Returns the number of overruns.
817 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
822 delta = ktime_sub(now, hrtimer_get_expires(timer));
827 if (interval.tv64 < timer->base->resolution.tv64)
828 interval.tv64 = timer->base->resolution.tv64;
830 if (unlikely(delta.tv64 >= interval.tv64)) {
831 s64 incr = ktime_to_ns(interval);
833 orun = ktime_divns(delta, incr);
834 hrtimer_add_expires_ns(timer, incr * orun);
835 if (hrtimer_get_expires_tv64(timer) > now.tv64)
838 * This (and the ktime_add() below) is the
839 * correction for exact:
843 hrtimer_add_expires(timer, interval);
847 EXPORT_SYMBOL_GPL(hrtimer_forward);
850 * enqueue_hrtimer - internal function to (re)start a timer
852 * The timer is inserted in expiry order. Insertion into the
853 * red black tree is O(log(n)). Must hold the base lock.
855 * Returns 1 when the new timer is the leftmost timer in the tree.
857 static int enqueue_hrtimer(struct hrtimer *timer,
858 struct hrtimer_clock_base *base)
860 debug_activate(timer);
862 timerqueue_add(&base->active, &timer->node);
863 base->cpu_base->active_bases |= 1 << base->index;
866 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
867 * state of a possibly running callback.
869 timer->state |= HRTIMER_STATE_ENQUEUED;
871 return (&timer->node == base->active.next);
875 * __remove_hrtimer - internal function to remove a timer
877 * Caller must hold the base lock.
879 * High resolution timer mode reprograms the clock event device when the
880 * timer is the one which expires next. The caller can disable this by setting
881 * reprogram to zero. This is useful, when the context does a reprogramming
882 * anyway (e.g. timer interrupt)
884 static void __remove_hrtimer(struct hrtimer *timer,
885 struct hrtimer_clock_base *base,
886 unsigned long newstate, int reprogram)
888 struct timerqueue_node *next_timer;
889 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
892 next_timer = timerqueue_getnext(&base->active);
893 timerqueue_del(&base->active, &timer->node);
894 if (&timer->node == next_timer) {
895 #ifdef CONFIG_HIGH_RES_TIMERS
896 /* Reprogram the clock event device. if enabled */
897 if (reprogram && hrtimer_hres_active()) {
900 expires = ktime_sub(hrtimer_get_expires(timer),
902 if (base->cpu_base->expires_next.tv64 == expires.tv64)
903 hrtimer_force_reprogram(base->cpu_base, 1);
907 if (!timerqueue_getnext(&base->active))
908 base->cpu_base->active_bases &= ~(1 << base->index);
910 timer->state = newstate;
914 * remove hrtimer, called with base lock held
917 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
919 if (hrtimer_is_queued(timer)) {
924 * Remove the timer and force reprogramming when high
925 * resolution mode is active and the timer is on the current
926 * CPU. If we remove a timer on another CPU, reprogramming is
927 * skipped. The interrupt event on this CPU is fired and
928 * reprogramming happens in the interrupt handler. This is a
929 * rare case and less expensive than a smp call.
931 debug_deactivate(timer);
932 timer_stats_hrtimer_clear_start_info(timer);
933 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
935 * We must preserve the CALLBACK state flag here,
936 * otherwise we could move the timer base in
937 * switch_hrtimer_base.
939 state = timer->state & HRTIMER_STATE_CALLBACK;
940 __remove_hrtimer(timer, base, state, reprogram);
946 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
947 unsigned long delta_ns, const enum hrtimer_mode mode,
950 struct hrtimer_clock_base *base, *new_base;
954 base = lock_hrtimer_base(timer, &flags);
956 /* Remove an active timer from the queue: */
957 ret = remove_hrtimer(timer, base);
959 /* Switch the timer base, if necessary: */
960 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
962 if (mode & HRTIMER_MODE_REL) {
963 tim = ktime_add_safe(tim, new_base->get_time());
965 * CONFIG_TIME_LOW_RES is a temporary way for architectures
966 * to signal that they simply return xtime in
967 * do_gettimeoffset(). In this case we want to round up by
968 * resolution when starting a relative timer, to avoid short
969 * timeouts. This will go away with the GTOD framework.
971 #ifdef CONFIG_TIME_LOW_RES
972 tim = ktime_add_safe(tim, base->resolution);
976 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
978 timer_stats_hrtimer_set_start_info(timer);
980 leftmost = enqueue_hrtimer(timer, new_base);
983 * Only allow reprogramming if the new base is on this CPU.
984 * (it might still be on another CPU if the timer was pending)
986 * XXX send_remote_softirq() ?
988 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
989 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
991 unlock_hrtimer_base(timer, &flags);
997 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
998 * @timer: the timer to be added
1000 * @delta_ns: "slack" range for the timer
1001 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1005 * 1 when the timer was active
1007 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1008 unsigned long delta_ns, const enum hrtimer_mode mode)
1010 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1012 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1015 * hrtimer_start - (re)start an hrtimer on the current CPU
1016 * @timer: the timer to be added
1018 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1022 * 1 when the timer was active
1025 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1027 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1029 EXPORT_SYMBOL_GPL(hrtimer_start);
1033 * hrtimer_try_to_cancel - try to deactivate a timer
1034 * @timer: hrtimer to stop
1037 * 0 when the timer was not active
1038 * 1 when the timer was active
1039 * -1 when the timer is currently excuting the callback function and
1042 int hrtimer_try_to_cancel(struct hrtimer *timer)
1044 struct hrtimer_clock_base *base;
1045 unsigned long flags;
1048 base = lock_hrtimer_base(timer, &flags);
1050 if (!hrtimer_callback_running(timer))
1051 ret = remove_hrtimer(timer, base);
1053 unlock_hrtimer_base(timer, &flags);
1058 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1061 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1062 * @timer: the timer to be cancelled
1065 * 0 when the timer was not active
1066 * 1 when the timer was active
1068 int hrtimer_cancel(struct hrtimer *timer)
1071 int ret = hrtimer_try_to_cancel(timer);
1078 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1081 * hrtimer_get_remaining - get remaining time for the timer
1082 * @timer: the timer to read
1084 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1086 unsigned long flags;
1089 lock_hrtimer_base(timer, &flags);
1090 rem = hrtimer_expires_remaining(timer);
1091 unlock_hrtimer_base(timer, &flags);
1095 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1099 * hrtimer_get_next_event - get the time until next expiry event
1101 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1104 ktime_t hrtimer_get_next_event(void)
1106 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1107 struct hrtimer_clock_base *base = cpu_base->clock_base;
1108 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1109 unsigned long flags;
1112 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1114 if (!hrtimer_hres_active()) {
1115 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1116 struct hrtimer *timer;
1117 struct timerqueue_node *next;
1119 next = timerqueue_getnext(&base->active);
1123 timer = container_of(next, struct hrtimer, node);
1124 delta.tv64 = hrtimer_get_expires_tv64(timer);
1125 delta = ktime_sub(delta, base->get_time());
1126 if (delta.tv64 < mindelta.tv64)
1127 mindelta.tv64 = delta.tv64;
1131 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1133 if (mindelta.tv64 < 0)
1139 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1140 enum hrtimer_mode mode)
1142 struct hrtimer_cpu_base *cpu_base;
1145 memset(timer, 0, sizeof(struct hrtimer));
1147 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1149 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1150 clock_id = CLOCK_MONOTONIC;
1152 base = hrtimer_clockid_to_base(clock_id);
1153 timer->base = &cpu_base->clock_base[base];
1154 timerqueue_init(&timer->node);
1156 #ifdef CONFIG_TIMER_STATS
1157 timer->start_site = NULL;
1158 timer->start_pid = -1;
1159 memset(timer->start_comm, 0, TASK_COMM_LEN);
1164 * hrtimer_init - initialize a timer to the given clock
1165 * @timer: the timer to be initialized
1166 * @clock_id: the clock to be used
1167 * @mode: timer mode abs/rel
1169 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1170 enum hrtimer_mode mode)
1172 debug_init(timer, clock_id, mode);
1173 __hrtimer_init(timer, clock_id, mode);
1175 EXPORT_SYMBOL_GPL(hrtimer_init);
1178 * hrtimer_get_res - get the timer resolution for a clock
1179 * @which_clock: which clock to query
1180 * @tp: pointer to timespec variable to store the resolution
1182 * Store the resolution of the clock selected by @which_clock in the
1183 * variable pointed to by @tp.
1185 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1187 struct hrtimer_cpu_base *cpu_base;
1188 int base = hrtimer_clockid_to_base(which_clock);
1190 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1191 *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
1195 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1197 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1199 struct hrtimer_clock_base *base = timer->base;
1200 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1201 enum hrtimer_restart (*fn)(struct hrtimer *);
1204 WARN_ON(!irqs_disabled());
1206 debug_deactivate(timer);
1207 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1208 timer_stats_account_hrtimer(timer);
1209 fn = timer->function;
1212 * Because we run timers from hardirq context, there is no chance
1213 * they get migrated to another cpu, therefore its safe to unlock
1216 raw_spin_unlock(&cpu_base->lock);
1217 trace_hrtimer_expire_entry(timer, now);
1218 restart = fn(timer);
1219 trace_hrtimer_expire_exit(timer);
1220 raw_spin_lock(&cpu_base->lock);
1223 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1224 * we do not reprogramm the event hardware. Happens either in
1225 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1227 if (restart != HRTIMER_NORESTART) {
1228 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1229 enqueue_hrtimer(timer, base);
1232 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1234 timer->state &= ~HRTIMER_STATE_CALLBACK;
1237 #ifdef CONFIG_HIGH_RES_TIMERS
1240 * High resolution timer interrupt
1241 * Called with interrupts disabled
1243 void hrtimer_interrupt(struct clock_event_device *dev)
1245 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1246 ktime_t expires_next, now, entry_time, delta;
1249 BUG_ON(!cpu_base->hres_active);
1250 cpu_base->nr_events++;
1251 dev->next_event.tv64 = KTIME_MAX;
1253 entry_time = now = ktime_get();
1255 expires_next.tv64 = KTIME_MAX;
1257 raw_spin_lock(&cpu_base->lock);
1259 * We set expires_next to KTIME_MAX here with cpu_base->lock
1260 * held to prevent that a timer is enqueued in our queue via
1261 * the migration code. This does not affect enqueueing of
1262 * timers which run their callback and need to be requeued on
1265 cpu_base->expires_next.tv64 = KTIME_MAX;
1267 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1268 struct hrtimer_clock_base *base;
1269 struct timerqueue_node *node;
1272 if (!(cpu_base->active_bases & (1 << i)))
1275 base = cpu_base->clock_base + i;
1276 basenow = ktime_add(now, base->offset);
1278 while ((node = timerqueue_getnext(&base->active))) {
1279 struct hrtimer *timer;
1281 timer = container_of(node, struct hrtimer, node);
1284 * The immediate goal for using the softexpires is
1285 * minimizing wakeups, not running timers at the
1286 * earliest interrupt after their soft expiration.
1287 * This allows us to avoid using a Priority Search
1288 * Tree, which can answer a stabbing querry for
1289 * overlapping intervals and instead use the simple
1290 * BST we already have.
1291 * We don't add extra wakeups by delaying timers that
1292 * are right-of a not yet expired timer, because that
1293 * timer will have to trigger a wakeup anyway.
1296 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1299 expires = ktime_sub(hrtimer_get_expires(timer),
1301 if (expires.tv64 < expires_next.tv64)
1302 expires_next = expires;
1306 __run_hrtimer(timer, &basenow);
1311 * Store the new expiry value so the migration code can verify
1314 cpu_base->expires_next = expires_next;
1315 raw_spin_unlock(&cpu_base->lock);
1317 /* Reprogramming necessary ? */
1318 if (expires_next.tv64 == KTIME_MAX ||
1319 !tick_program_event(expires_next, 0)) {
1320 cpu_base->hang_detected = 0;
1325 * The next timer was already expired due to:
1327 * - long lasting callbacks
1328 * - being scheduled away when running in a VM
1330 * We need to prevent that we loop forever in the hrtimer
1331 * interrupt routine. We give it 3 attempts to avoid
1332 * overreacting on some spurious event.
1335 cpu_base->nr_retries++;
1339 * Give the system a chance to do something else than looping
1340 * here. We stored the entry time, so we know exactly how long
1341 * we spent here. We schedule the next event this amount of
1344 cpu_base->nr_hangs++;
1345 cpu_base->hang_detected = 1;
1346 delta = ktime_sub(now, entry_time);
1347 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1348 cpu_base->max_hang_time = delta;
1350 * Limit it to a sensible value as we enforce a longer
1351 * delay. Give the CPU at least 100ms to catch up.
1353 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1354 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1356 expires_next = ktime_add(now, delta);
1357 tick_program_event(expires_next, 1);
1358 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1359 ktime_to_ns(delta));
1363 * local version of hrtimer_peek_ahead_timers() called with interrupts
1366 static void __hrtimer_peek_ahead_timers(void)
1368 struct tick_device *td;
1370 if (!hrtimer_hres_active())
1373 td = &__get_cpu_var(tick_cpu_device);
1374 if (td && td->evtdev)
1375 hrtimer_interrupt(td->evtdev);
1379 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1381 * hrtimer_peek_ahead_timers will peek at the timer queue of
1382 * the current cpu and check if there are any timers for which
1383 * the soft expires time has passed. If any such timers exist,
1384 * they are run immediately and then removed from the timer queue.
1387 void hrtimer_peek_ahead_timers(void)
1389 unsigned long flags;
1391 local_irq_save(flags);
1392 __hrtimer_peek_ahead_timers();
1393 local_irq_restore(flags);
1396 static void run_hrtimer_softirq(struct softirq_action *h)
1398 hrtimer_peek_ahead_timers();
1401 #else /* CONFIG_HIGH_RES_TIMERS */
1403 static inline void __hrtimer_peek_ahead_timers(void) { }
1405 #endif /* !CONFIG_HIGH_RES_TIMERS */
1408 * Called from timer softirq every jiffy, expire hrtimers:
1410 * For HRT its the fall back code to run the softirq in the timer
1411 * softirq context in case the hrtimer initialization failed or has
1412 * not been done yet.
1414 void hrtimer_run_pending(void)
1416 if (hrtimer_hres_active())
1420 * This _is_ ugly: We have to check in the softirq context,
1421 * whether we can switch to highres and / or nohz mode. The
1422 * clocksource switch happens in the timer interrupt with
1423 * xtime_lock held. Notification from there only sets the
1424 * check bit in the tick_oneshot code, otherwise we might
1425 * deadlock vs. xtime_lock.
1427 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1428 hrtimer_switch_to_hres();
1432 * Called from hardirq context every jiffy
1434 void hrtimer_run_queues(void)
1436 struct timerqueue_node *node;
1437 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1438 struct hrtimer_clock_base *base;
1439 int index, gettime = 1;
1441 if (hrtimer_hres_active())
1444 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1445 base = &cpu_base->clock_base[index];
1446 if (!timerqueue_getnext(&base->active))
1450 hrtimer_get_softirq_time(cpu_base);
1454 raw_spin_lock(&cpu_base->lock);
1456 while ((node = timerqueue_getnext(&base->active))) {
1457 struct hrtimer *timer;
1459 timer = container_of(node, struct hrtimer, node);
1460 if (base->softirq_time.tv64 <=
1461 hrtimer_get_expires_tv64(timer))
1464 __run_hrtimer(timer, &base->softirq_time);
1466 raw_spin_unlock(&cpu_base->lock);
1471 * Sleep related functions:
1473 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1475 struct hrtimer_sleeper *t =
1476 container_of(timer, struct hrtimer_sleeper, timer);
1477 struct task_struct *task = t->task;
1481 wake_up_process(task);
1483 return HRTIMER_NORESTART;
1486 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1488 sl->timer.function = hrtimer_wakeup;
1491 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1493 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1495 hrtimer_init_sleeper(t, current);
1498 set_current_state(TASK_INTERRUPTIBLE);
1499 hrtimer_start_expires(&t->timer, mode);
1500 if (!hrtimer_active(&t->timer))
1503 if (likely(t->task))
1506 hrtimer_cancel(&t->timer);
1507 mode = HRTIMER_MODE_ABS;
1509 } while (t->task && !signal_pending(current));
1511 __set_current_state(TASK_RUNNING);
1513 return t->task == NULL;
1516 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1518 struct timespec rmt;
1521 rem = hrtimer_expires_remaining(timer);
1524 rmt = ktime_to_timespec(rem);
1526 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1532 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1534 struct hrtimer_sleeper t;
1535 struct timespec __user *rmtp;
1538 hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
1540 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1542 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1545 rmtp = restart->nanosleep.rmtp;
1547 ret = update_rmtp(&t.timer, rmtp);
1552 /* The other values in restart are already filled in */
1553 ret = -ERESTART_RESTARTBLOCK;
1555 destroy_hrtimer_on_stack(&t.timer);
1559 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1560 const enum hrtimer_mode mode, const clockid_t clockid)
1562 struct restart_block *restart;
1563 struct hrtimer_sleeper t;
1565 unsigned long slack;
1567 slack = current->timer_slack_ns;
1568 if (rt_task(current))
1571 hrtimer_init_on_stack(&t.timer, clockid, mode);
1572 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1573 if (do_nanosleep(&t, mode))
1576 /* Absolute timers do not update the rmtp value and restart: */
1577 if (mode == HRTIMER_MODE_ABS) {
1578 ret = -ERESTARTNOHAND;
1583 ret = update_rmtp(&t.timer, rmtp);
1588 restart = ¤t_thread_info()->restart_block;
1589 restart->fn = hrtimer_nanosleep_restart;
1590 restart->nanosleep.clockid = t.timer.base->clockid;
1591 restart->nanosleep.rmtp = rmtp;
1592 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1594 ret = -ERESTART_RESTARTBLOCK;
1596 destroy_hrtimer_on_stack(&t.timer);
1600 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1601 struct timespec __user *, rmtp)
1605 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1608 if (!timespec_valid(&tu))
1611 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1615 * Functions related to boot-time initialization:
1617 static void __cpuinit init_hrtimers_cpu(int cpu)
1619 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1622 raw_spin_lock_init(&cpu_base->lock);
1624 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1625 cpu_base->clock_base[i].cpu_base = cpu_base;
1626 timerqueue_init_head(&cpu_base->clock_base[i].active);
1629 hrtimer_init_hres(cpu_base);
1632 #ifdef CONFIG_HOTPLUG_CPU
1634 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1635 struct hrtimer_clock_base *new_base)
1637 struct hrtimer *timer;
1638 struct timerqueue_node *node;
1640 while ((node = timerqueue_getnext(&old_base->active))) {
1641 timer = container_of(node, struct hrtimer, node);
1642 BUG_ON(hrtimer_callback_running(timer));
1643 debug_deactivate(timer);
1646 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1647 * timer could be seen as !active and just vanish away
1648 * under us on another CPU
1650 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1651 timer->base = new_base;
1653 * Enqueue the timers on the new cpu. This does not
1654 * reprogram the event device in case the timer
1655 * expires before the earliest on this CPU, but we run
1656 * hrtimer_interrupt after we migrated everything to
1657 * sort out already expired timers and reprogram the
1660 enqueue_hrtimer(timer, new_base);
1662 /* Clear the migration state bit */
1663 timer->state &= ~HRTIMER_STATE_MIGRATE;
1667 static void migrate_hrtimers(int scpu)
1669 struct hrtimer_cpu_base *old_base, *new_base;
1672 BUG_ON(cpu_online(scpu));
1673 tick_cancel_sched_timer(scpu);
1675 local_irq_disable();
1676 old_base = &per_cpu(hrtimer_bases, scpu);
1677 new_base = &__get_cpu_var(hrtimer_bases);
1679 * The caller is globally serialized and nobody else
1680 * takes two locks at once, deadlock is not possible.
1682 raw_spin_lock(&new_base->lock);
1683 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1685 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1686 migrate_hrtimer_list(&old_base->clock_base[i],
1687 &new_base->clock_base[i]);
1690 raw_spin_unlock(&old_base->lock);
1691 raw_spin_unlock(&new_base->lock);
1693 /* Check, if we got expired work to do */
1694 __hrtimer_peek_ahead_timers();
1698 #endif /* CONFIG_HOTPLUG_CPU */
1700 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1701 unsigned long action, void *hcpu)
1703 int scpu = (long)hcpu;
1707 case CPU_UP_PREPARE:
1708 case CPU_UP_PREPARE_FROZEN:
1709 init_hrtimers_cpu(scpu);
1712 #ifdef CONFIG_HOTPLUG_CPU
1714 case CPU_DYING_FROZEN:
1715 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1718 case CPU_DEAD_FROZEN:
1720 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1721 migrate_hrtimers(scpu);
1733 static struct notifier_block __cpuinitdata hrtimers_nb = {
1734 .notifier_call = hrtimer_cpu_notify,
1737 void __init hrtimers_init(void)
1739 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1740 (void *)(long)smp_processor_id());
1741 register_cpu_notifier(&hrtimers_nb);
1742 #ifdef CONFIG_HIGH_RES_TIMERS
1743 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1748 * schedule_hrtimeout_range_clock - sleep until timeout
1749 * @expires: timeout value (ktime_t)
1750 * @delta: slack in expires timeout (ktime_t)
1751 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1752 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1755 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1756 const enum hrtimer_mode mode, int clock)
1758 struct hrtimer_sleeper t;
1761 * Optimize when a zero timeout value is given. It does not
1762 * matter whether this is an absolute or a relative time.
1764 if (expires && !expires->tv64) {
1765 __set_current_state(TASK_RUNNING);
1770 * A NULL parameter means "infinite"
1774 __set_current_state(TASK_RUNNING);
1778 hrtimer_init_on_stack(&t.timer, clock, mode);
1779 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1781 hrtimer_init_sleeper(&t, current);
1783 hrtimer_start_expires(&t.timer, mode);
1784 if (!hrtimer_active(&t.timer))
1790 hrtimer_cancel(&t.timer);
1791 destroy_hrtimer_on_stack(&t.timer);
1793 __set_current_state(TASK_RUNNING);
1795 return !t.task ? 0 : -EINTR;
1799 * schedule_hrtimeout_range - sleep until timeout
1800 * @expires: timeout value (ktime_t)
1801 * @delta: slack in expires timeout (ktime_t)
1802 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1804 * Make the current task sleep until the given expiry time has
1805 * elapsed. The routine will return immediately unless
1806 * the current task state has been set (see set_current_state()).
1808 * The @delta argument gives the kernel the freedom to schedule the
1809 * actual wakeup to a time that is both power and performance friendly.
1810 * The kernel give the normal best effort behavior for "@expires+@delta",
1811 * but may decide to fire the timer earlier, but no earlier than @expires.
1813 * You can set the task state as follows -
1815 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1816 * pass before the routine returns.
1818 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1819 * delivered to the current task.
1821 * The current task state is guaranteed to be TASK_RUNNING when this
1824 * Returns 0 when the timer has expired otherwise -EINTR
1826 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1827 const enum hrtimer_mode mode)
1829 return schedule_hrtimeout_range_clock(expires, delta, mode,
1832 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1835 * schedule_hrtimeout - sleep until timeout
1836 * @expires: timeout value (ktime_t)
1837 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1839 * Make the current task sleep until the given expiry time has
1840 * elapsed. The routine will return immediately unless
1841 * the current task state has been set (see set_current_state()).
1843 * You can set the task state as follows -
1845 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1846 * pass before the routine returns.
1848 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1849 * delivered to the current task.
1851 * The current task state is guaranteed to be TASK_RUNNING when this
1854 * Returns 0 when the timer has expired otherwise -EINTR
1856 int __sched schedule_hrtimeout(ktime_t *expires,
1857 const enum hrtimer_mode mode)
1859 return schedule_hrtimeout_range(expires, 0, mode);
1861 EXPORT_SYMBOL_GPL(schedule_hrtimeout);