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/module.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 = CLOCK_REALTIME,
68 .get_time = &ktime_get_real,
69 .resolution = KTIME_LOW_RES,
72 .index = CLOCK_MONOTONIC,
73 .get_time = &ktime_get,
74 .resolution = KTIME_LOW_RES,
77 .index = CLOCK_BOOTTIME,
78 .get_time = &ktime_get_boottime,
79 .resolution = KTIME_LOW_RES,
84 static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
85 [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
86 [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
87 [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
90 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
92 return hrtimer_clock_to_base_table[clock_id];
97 * Get the coarse grained time at the softirq based on xtime and
100 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
102 ktime_t xtim, mono, boot;
103 struct timespec xts, tom, slp;
105 get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
107 xtim = timespec_to_ktime(xts);
108 mono = ktime_add(xtim, timespec_to_ktime(tom));
109 boot = ktime_add(mono, timespec_to_ktime(slp));
110 base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
111 base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
112 base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
116 * Functions and macros which are different for UP/SMP systems are kept in a
122 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
123 * means that all timers which are tied to this base via timer->base are
124 * locked, and the base itself is locked too.
126 * So __run_timers/migrate_timers can safely modify all timers which could
127 * be found on the lists/queues.
129 * When the timer's base is locked, and the timer removed from list, it is
130 * possible to set timer->base = NULL and drop the lock: the timer remains
134 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
135 unsigned long *flags)
137 struct hrtimer_clock_base *base;
141 if (likely(base != NULL)) {
142 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
143 if (likely(base == timer->base))
145 /* The timer has migrated to another CPU: */
146 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
154 * Get the preferred target CPU for NOHZ
156 static int hrtimer_get_target(int this_cpu, int pinned)
159 if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
160 return get_nohz_timer_target();
166 * With HIGHRES=y we do not migrate the timer when it is expiring
167 * before the next event on the target cpu because we cannot reprogram
168 * the target cpu hardware and we would cause it to fire late.
170 * Called with cpu_base->lock of target cpu held.
173 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
175 #ifdef CONFIG_HIGH_RES_TIMERS
178 if (!new_base->cpu_base->hres_active)
181 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
182 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
189 * Switch the timer base to the current CPU when possible.
191 static inline struct hrtimer_clock_base *
192 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
195 struct hrtimer_clock_base *new_base;
196 struct hrtimer_cpu_base *new_cpu_base;
197 int this_cpu = smp_processor_id();
198 int cpu = hrtimer_get_target(this_cpu, pinned);
199 int basenum = hrtimer_clockid_to_base(base->index);
202 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
203 new_base = &new_cpu_base->clock_base[basenum];
205 if (base != new_base) {
207 * We are trying to move timer to new_base.
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)))
218 /* See the comment in lock_timer_base() */
220 raw_spin_unlock(&base->cpu_base->lock);
221 raw_spin_lock(&new_base->cpu_base->lock);
223 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
225 raw_spin_unlock(&new_base->cpu_base->lock);
226 raw_spin_lock(&base->cpu_base->lock);
230 timer->base = new_base;
235 #else /* CONFIG_SMP */
237 static inline struct hrtimer_clock_base *
238 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
240 struct hrtimer_clock_base *base = timer->base;
242 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
247 # define switch_hrtimer_base(t, b, p) (b)
249 #endif /* !CONFIG_SMP */
252 * Functions for the union type storage format of ktime_t which are
253 * too large for inlining:
255 #if BITS_PER_LONG < 64
256 # ifndef CONFIG_KTIME_SCALAR
258 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
260 * @nsec: the scalar nsec value to add
262 * Returns the sum of kt and nsec in ktime_t format
264 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
268 if (likely(nsec < NSEC_PER_SEC)) {
271 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
273 tmp = ktime_set((long)nsec, rem);
276 return ktime_add(kt, tmp);
279 EXPORT_SYMBOL_GPL(ktime_add_ns);
282 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
284 * @nsec: the scalar nsec value to subtract
286 * Returns the subtraction of @nsec from @kt in ktime_t format
288 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
292 if (likely(nsec < NSEC_PER_SEC)) {
295 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
297 tmp = ktime_set((long)nsec, rem);
300 return ktime_sub(kt, tmp);
303 EXPORT_SYMBOL_GPL(ktime_sub_ns);
304 # endif /* !CONFIG_KTIME_SCALAR */
307 * Divide a ktime value by a nanosecond value
309 u64 ktime_divns(const ktime_t kt, s64 div)
314 dclc = ktime_to_ns(kt);
315 /* Make sure the divisor is less than 2^32: */
321 do_div(dclc, (unsigned long) div);
325 #endif /* BITS_PER_LONG >= 64 */
328 * Add two ktime values and do a safety check for overflow:
330 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
332 ktime_t res = ktime_add(lhs, rhs);
335 * We use KTIME_SEC_MAX here, the maximum timeout which we can
336 * return to user space in a timespec:
338 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
339 res = ktime_set(KTIME_SEC_MAX, 0);
344 EXPORT_SYMBOL_GPL(ktime_add_safe);
346 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
348 static struct debug_obj_descr hrtimer_debug_descr;
350 static void *hrtimer_debug_hint(void *addr)
352 return ((struct hrtimer *) addr)->function;
356 * fixup_init is called when:
357 * - an active object is initialized
359 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
361 struct hrtimer *timer = addr;
364 case ODEBUG_STATE_ACTIVE:
365 hrtimer_cancel(timer);
366 debug_object_init(timer, &hrtimer_debug_descr);
374 * fixup_activate is called when:
375 * - an active object is activated
376 * - an unknown object is activated (might be a statically initialized object)
378 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
382 case ODEBUG_STATE_NOTAVAILABLE:
386 case ODEBUG_STATE_ACTIVE:
395 * fixup_free is called when:
396 * - an active object is freed
398 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
400 struct hrtimer *timer = addr;
403 case ODEBUG_STATE_ACTIVE:
404 hrtimer_cancel(timer);
405 debug_object_free(timer, &hrtimer_debug_descr);
412 static struct debug_obj_descr hrtimer_debug_descr = {
414 .debug_hint = hrtimer_debug_hint,
415 .fixup_init = hrtimer_fixup_init,
416 .fixup_activate = hrtimer_fixup_activate,
417 .fixup_free = hrtimer_fixup_free,
420 static inline void debug_hrtimer_init(struct hrtimer *timer)
422 debug_object_init(timer, &hrtimer_debug_descr);
425 static inline void debug_hrtimer_activate(struct hrtimer *timer)
427 debug_object_activate(timer, &hrtimer_debug_descr);
430 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
432 debug_object_deactivate(timer, &hrtimer_debug_descr);
435 static inline void debug_hrtimer_free(struct hrtimer *timer)
437 debug_object_free(timer, &hrtimer_debug_descr);
440 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
441 enum hrtimer_mode mode);
443 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
444 enum hrtimer_mode mode)
446 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
447 __hrtimer_init(timer, clock_id, mode);
449 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
451 void destroy_hrtimer_on_stack(struct hrtimer *timer)
453 debug_object_free(timer, &hrtimer_debug_descr);
457 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
458 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
459 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
463 debug_init(struct hrtimer *timer, clockid_t clockid,
464 enum hrtimer_mode mode)
466 debug_hrtimer_init(timer);
467 trace_hrtimer_init(timer, clockid, mode);
470 static inline void debug_activate(struct hrtimer *timer)
472 debug_hrtimer_activate(timer);
473 trace_hrtimer_start(timer);
476 static inline void debug_deactivate(struct hrtimer *timer)
478 debug_hrtimer_deactivate(timer);
479 trace_hrtimer_cancel(timer);
482 /* High resolution timer related functions */
483 #ifdef CONFIG_HIGH_RES_TIMERS
486 * High resolution timer enabled ?
488 static int hrtimer_hres_enabled __read_mostly = 1;
491 * Enable / Disable high resolution mode
493 static int __init setup_hrtimer_hres(char *str)
495 if (!strcmp(str, "off"))
496 hrtimer_hres_enabled = 0;
497 else if (!strcmp(str, "on"))
498 hrtimer_hres_enabled = 1;
504 __setup("highres=", setup_hrtimer_hres);
507 * hrtimer_high_res_enabled - query, if the highres mode is enabled
509 static inline int hrtimer_is_hres_enabled(void)
511 return hrtimer_hres_enabled;
515 * Is the high resolution mode active ?
517 static inline int hrtimer_hres_active(void)
519 return __this_cpu_read(hrtimer_bases.hres_active);
523 * Reprogram the event source with checking both queues for the
525 * Called with interrupts disabled and base->lock held
528 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
531 struct hrtimer_clock_base *base = cpu_base->clock_base;
532 ktime_t expires, expires_next;
534 expires_next.tv64 = KTIME_MAX;
536 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
537 struct hrtimer *timer;
538 struct timerqueue_node *next;
540 next = timerqueue_getnext(&base->active);
543 timer = container_of(next, struct hrtimer, node);
545 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
547 * clock_was_set() has changed base->offset so the
548 * result might be negative. Fix it up to prevent a
549 * false positive in clockevents_program_event()
551 if (expires.tv64 < 0)
553 if (expires.tv64 < expires_next.tv64)
554 expires_next = expires;
557 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
560 cpu_base->expires_next.tv64 = expires_next.tv64;
562 if (cpu_base->expires_next.tv64 != KTIME_MAX)
563 tick_program_event(cpu_base->expires_next, 1);
567 * Shared reprogramming for clock_realtime and clock_monotonic
569 * When a timer is enqueued and expires earlier than the already enqueued
570 * timers, we have to check, whether it expires earlier than the timer for
571 * which the clock event device was armed.
573 * Called with interrupts disabled and base->cpu_base.lock held
575 static int hrtimer_reprogram(struct hrtimer *timer,
576 struct hrtimer_clock_base *base)
578 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
579 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
582 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
585 * When the callback is running, we do not reprogram the clock event
586 * device. The timer callback is either running on a different CPU or
587 * the callback is executed in the hrtimer_interrupt context. The
588 * reprogramming is handled either by the softirq, which called the
589 * callback or at the end of the hrtimer_interrupt.
591 if (hrtimer_callback_running(timer))
595 * CLOCK_REALTIME timer might be requested with an absolute
596 * expiry time which is less than base->offset. Nothing wrong
597 * about that, just avoid to call into the tick code, which
598 * has now objections against negative expiry values.
600 if (expires.tv64 < 0)
603 if (expires.tv64 >= cpu_base->expires_next.tv64)
607 * If a hang was detected in the last timer interrupt then we
608 * do not schedule a timer which is earlier than the expiry
609 * which we enforced in the hang detection. We want the system
612 if (cpu_base->hang_detected)
616 * Clockevents returns -ETIME, when the event was in the past.
618 res = tick_program_event(expires, 0);
619 if (!IS_ERR_VALUE(res))
620 cpu_base->expires_next = expires;
626 * Retrigger next event is called after clock was set
628 * Called with interrupts disabled via on_each_cpu()
630 static void retrigger_next_event(void *arg)
632 struct hrtimer_cpu_base *base;
633 struct timespec realtime_offset, wtm, sleep;
635 if (!hrtimer_hres_active())
638 get_xtime_and_monotonic_and_sleep_offset(&realtime_offset, &wtm,
640 set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
642 base = &__get_cpu_var(hrtimer_bases);
644 /* Adjust CLOCK_REALTIME offset */
645 raw_spin_lock(&base->lock);
646 base->clock_base[HRTIMER_BASE_REALTIME].offset =
647 timespec_to_ktime(realtime_offset);
648 base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
649 timespec_to_ktime(sleep);
651 hrtimer_force_reprogram(base, 0);
652 raw_spin_unlock(&base->lock);
656 * Clock realtime was set
658 * Change the offset of the realtime clock vs. the monotonic
661 * We might have to reprogram the high resolution timer interrupt. On
662 * SMP we call the architecture specific code to retrigger _all_ high
663 * resolution timer interrupts. On UP we just disable interrupts and
664 * call the high resolution interrupt code.
666 void clock_was_set(void)
668 /* Retrigger the CPU local events everywhere */
669 on_each_cpu(retrigger_next_event, NULL, 1);
673 * During resume we might have to reprogram the high resolution timer
674 * interrupt (on the local CPU):
676 void hres_timers_resume(void)
678 WARN_ONCE(!irqs_disabled(),
679 KERN_INFO "hres_timers_resume() called with IRQs enabled!");
681 retrigger_next_event(NULL);
685 * Initialize the high resolution related parts of cpu_base
687 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
689 base->expires_next.tv64 = KTIME_MAX;
690 base->hres_active = 0;
694 * When High resolution timers are active, try to reprogram. Note, that in case
695 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
696 * check happens. The timer gets enqueued into the rbtree. The reprogramming
697 * and expiry check is done in the hrtimer_interrupt or in the softirq.
699 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
700 struct hrtimer_clock_base *base,
703 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
705 raw_spin_unlock(&base->cpu_base->lock);
706 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
707 raw_spin_lock(&base->cpu_base->lock);
709 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
718 * Switch to high resolution mode
720 static int hrtimer_switch_to_hres(void)
722 int cpu = smp_processor_id();
723 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
726 if (base->hres_active)
729 local_irq_save(flags);
731 if (tick_init_highres()) {
732 local_irq_restore(flags);
733 printk(KERN_WARNING "Could not switch to high resolution "
734 "mode on CPU %d\n", cpu);
737 base->hres_active = 1;
738 base->clock_base[HRTIMER_BASE_REALTIME].resolution = KTIME_HIGH_RES;
739 base->clock_base[HRTIMER_BASE_MONOTONIC].resolution = KTIME_HIGH_RES;
740 base->clock_base[HRTIMER_BASE_BOOTTIME].resolution = KTIME_HIGH_RES;
742 tick_setup_sched_timer();
744 /* "Retrigger" the interrupt to get things going */
745 retrigger_next_event(NULL);
746 local_irq_restore(flags);
752 static inline int hrtimer_hres_active(void) { return 0; }
753 static inline int hrtimer_is_hres_enabled(void) { return 0; }
754 static inline int hrtimer_switch_to_hres(void) { return 0; }
756 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
757 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
758 struct hrtimer_clock_base *base,
763 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
765 #endif /* CONFIG_HIGH_RES_TIMERS */
767 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
769 #ifdef CONFIG_TIMER_STATS
770 if (timer->start_site)
772 timer->start_site = __builtin_return_address(0);
773 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
774 timer->start_pid = current->pid;
778 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
780 #ifdef CONFIG_TIMER_STATS
781 timer->start_site = NULL;
785 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
787 #ifdef CONFIG_TIMER_STATS
788 if (likely(!timer_stats_active))
790 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
791 timer->function, timer->start_comm, 0);
796 * Counterpart to lock_hrtimer_base above:
799 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
801 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
805 * hrtimer_forward - forward the timer expiry
806 * @timer: hrtimer to forward
807 * @now: forward past this time
808 * @interval: the interval to forward
810 * Forward the timer expiry so it will expire in the future.
811 * Returns the number of overruns.
813 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
818 delta = ktime_sub(now, hrtimer_get_expires(timer));
823 if (interval.tv64 < timer->base->resolution.tv64)
824 interval.tv64 = timer->base->resolution.tv64;
826 if (unlikely(delta.tv64 >= interval.tv64)) {
827 s64 incr = ktime_to_ns(interval);
829 orun = ktime_divns(delta, incr);
830 hrtimer_add_expires_ns(timer, incr * orun);
831 if (hrtimer_get_expires_tv64(timer) > now.tv64)
834 * This (and the ktime_add() below) is the
835 * correction for exact:
839 hrtimer_add_expires(timer, interval);
843 EXPORT_SYMBOL_GPL(hrtimer_forward);
846 * enqueue_hrtimer - internal function to (re)start a timer
848 * The timer is inserted in expiry order. Insertion into the
849 * red black tree is O(log(n)). Must hold the base lock.
851 * Returns 1 when the new timer is the leftmost timer in the tree.
853 static int enqueue_hrtimer(struct hrtimer *timer,
854 struct hrtimer_clock_base *base)
856 debug_activate(timer);
858 timerqueue_add(&base->active, &timer->node);
861 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
862 * state of a possibly running callback.
864 timer->state |= HRTIMER_STATE_ENQUEUED;
866 return (&timer->node == base->active.next);
870 * __remove_hrtimer - internal function to remove a timer
872 * Caller must hold the base lock.
874 * High resolution timer mode reprograms the clock event device when the
875 * timer is the one which expires next. The caller can disable this by setting
876 * reprogram to zero. This is useful, when the context does a reprogramming
877 * anyway (e.g. timer interrupt)
879 static void __remove_hrtimer(struct hrtimer *timer,
880 struct hrtimer_clock_base *base,
881 unsigned long newstate, int reprogram)
883 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
886 if (&timer->node == timerqueue_getnext(&base->active)) {
887 #ifdef CONFIG_HIGH_RES_TIMERS
888 /* Reprogram the clock event device. if enabled */
889 if (reprogram && hrtimer_hres_active()) {
892 expires = ktime_sub(hrtimer_get_expires(timer),
894 if (base->cpu_base->expires_next.tv64 == expires.tv64)
895 hrtimer_force_reprogram(base->cpu_base, 1);
899 timerqueue_del(&base->active, &timer->node);
901 timer->state = newstate;
905 * remove hrtimer, called with base lock held
908 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
910 if (hrtimer_is_queued(timer)) {
915 * Remove the timer and force reprogramming when high
916 * resolution mode is active and the timer is on the current
917 * CPU. If we remove a timer on another CPU, reprogramming is
918 * skipped. The interrupt event on this CPU is fired and
919 * reprogramming happens in the interrupt handler. This is a
920 * rare case and less expensive than a smp call.
922 debug_deactivate(timer);
923 timer_stats_hrtimer_clear_start_info(timer);
924 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
926 * We must preserve the CALLBACK state flag here,
927 * otherwise we could move the timer base in
928 * switch_hrtimer_base.
930 state = timer->state & HRTIMER_STATE_CALLBACK;
931 __remove_hrtimer(timer, base, state, reprogram);
937 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
938 unsigned long delta_ns, const enum hrtimer_mode mode,
941 struct hrtimer_clock_base *base, *new_base;
945 base = lock_hrtimer_base(timer, &flags);
947 /* Remove an active timer from the queue: */
948 ret = remove_hrtimer(timer, base);
950 /* Switch the timer base, if necessary: */
951 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
953 if (mode & HRTIMER_MODE_REL) {
954 tim = ktime_add_safe(tim, new_base->get_time());
956 * CONFIG_TIME_LOW_RES is a temporary way for architectures
957 * to signal that they simply return xtime in
958 * do_gettimeoffset(). In this case we want to round up by
959 * resolution when starting a relative timer, to avoid short
960 * timeouts. This will go away with the GTOD framework.
962 #ifdef CONFIG_TIME_LOW_RES
963 tim = ktime_add_safe(tim, base->resolution);
967 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
969 timer_stats_hrtimer_set_start_info(timer);
971 leftmost = enqueue_hrtimer(timer, new_base);
974 * Only allow reprogramming if the new base is on this CPU.
975 * (it might still be on another CPU if the timer was pending)
977 * XXX send_remote_softirq() ?
979 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
980 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
982 unlock_hrtimer_base(timer, &flags);
988 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
989 * @timer: the timer to be added
991 * @delta_ns: "slack" range for the timer
992 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
996 * 1 when the timer was active
998 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
999 unsigned long delta_ns, const enum hrtimer_mode mode)
1001 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1003 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1006 * hrtimer_start - (re)start an hrtimer on the current CPU
1007 * @timer: the timer to be added
1009 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1013 * 1 when the timer was active
1016 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1018 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1020 EXPORT_SYMBOL_GPL(hrtimer_start);
1024 * hrtimer_try_to_cancel - try to deactivate a timer
1025 * @timer: hrtimer to stop
1028 * 0 when the timer was not active
1029 * 1 when the timer was active
1030 * -1 when the timer is currently excuting the callback function and
1033 int hrtimer_try_to_cancel(struct hrtimer *timer)
1035 struct hrtimer_clock_base *base;
1036 unsigned long flags;
1039 base = lock_hrtimer_base(timer, &flags);
1041 if (!hrtimer_callback_running(timer))
1042 ret = remove_hrtimer(timer, base);
1044 unlock_hrtimer_base(timer, &flags);
1049 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1052 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1053 * @timer: the timer to be cancelled
1056 * 0 when the timer was not active
1057 * 1 when the timer was active
1059 int hrtimer_cancel(struct hrtimer *timer)
1062 int ret = hrtimer_try_to_cancel(timer);
1069 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1072 * hrtimer_get_remaining - get remaining time for the timer
1073 * @timer: the timer to read
1075 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1077 unsigned long flags;
1080 lock_hrtimer_base(timer, &flags);
1081 rem = hrtimer_expires_remaining(timer);
1082 unlock_hrtimer_base(timer, &flags);
1086 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1090 * hrtimer_get_next_event - get the time until next expiry event
1092 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1095 ktime_t hrtimer_get_next_event(void)
1097 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1098 struct hrtimer_clock_base *base = cpu_base->clock_base;
1099 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1100 unsigned long flags;
1103 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1105 if (!hrtimer_hres_active()) {
1106 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1107 struct hrtimer *timer;
1108 struct timerqueue_node *next;
1110 next = timerqueue_getnext(&base->active);
1114 timer = container_of(next, struct hrtimer, node);
1115 delta.tv64 = hrtimer_get_expires_tv64(timer);
1116 delta = ktime_sub(delta, base->get_time());
1117 if (delta.tv64 < mindelta.tv64)
1118 mindelta.tv64 = delta.tv64;
1122 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1124 if (mindelta.tv64 < 0)
1130 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1131 enum hrtimer_mode mode)
1133 struct hrtimer_cpu_base *cpu_base;
1136 memset(timer, 0, sizeof(struct hrtimer));
1138 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1140 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1141 clock_id = CLOCK_MONOTONIC;
1143 base = hrtimer_clockid_to_base(clock_id);
1144 timer->base = &cpu_base->clock_base[base];
1145 timerqueue_init(&timer->node);
1147 #ifdef CONFIG_TIMER_STATS
1148 timer->start_site = NULL;
1149 timer->start_pid = -1;
1150 memset(timer->start_comm, 0, TASK_COMM_LEN);
1155 * hrtimer_init - initialize a timer to the given clock
1156 * @timer: the timer to be initialized
1157 * @clock_id: the clock to be used
1158 * @mode: timer mode abs/rel
1160 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1161 enum hrtimer_mode mode)
1163 debug_init(timer, clock_id, mode);
1164 __hrtimer_init(timer, clock_id, mode);
1166 EXPORT_SYMBOL_GPL(hrtimer_init);
1169 * hrtimer_get_res - get the timer resolution for a clock
1170 * @which_clock: which clock to query
1171 * @tp: pointer to timespec variable to store the resolution
1173 * Store the resolution of the clock selected by @which_clock in the
1174 * variable pointed to by @tp.
1176 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1178 struct hrtimer_cpu_base *cpu_base;
1179 int base = hrtimer_clockid_to_base(which_clock);
1181 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1182 *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
1186 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1188 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1190 struct hrtimer_clock_base *base = timer->base;
1191 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1192 enum hrtimer_restart (*fn)(struct hrtimer *);
1195 WARN_ON(!irqs_disabled());
1197 debug_deactivate(timer);
1198 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1199 timer_stats_account_hrtimer(timer);
1200 fn = timer->function;
1203 * Because we run timers from hardirq context, there is no chance
1204 * they get migrated to another cpu, therefore its safe to unlock
1207 raw_spin_unlock(&cpu_base->lock);
1208 trace_hrtimer_expire_entry(timer, now);
1209 restart = fn(timer);
1210 trace_hrtimer_expire_exit(timer);
1211 raw_spin_lock(&cpu_base->lock);
1214 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1215 * we do not reprogramm the event hardware. Happens either in
1216 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1218 if (restart != HRTIMER_NORESTART) {
1219 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1220 enqueue_hrtimer(timer, base);
1223 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1225 timer->state &= ~HRTIMER_STATE_CALLBACK;
1228 #ifdef CONFIG_HIGH_RES_TIMERS
1231 * High resolution timer interrupt
1232 * Called with interrupts disabled
1234 void hrtimer_interrupt(struct clock_event_device *dev)
1236 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1237 struct hrtimer_clock_base *base;
1238 ktime_t expires_next, now, entry_time, delta;
1241 BUG_ON(!cpu_base->hres_active);
1242 cpu_base->nr_events++;
1243 dev->next_event.tv64 = KTIME_MAX;
1245 entry_time = now = ktime_get();
1247 expires_next.tv64 = KTIME_MAX;
1249 raw_spin_lock(&cpu_base->lock);
1251 * We set expires_next to KTIME_MAX here with cpu_base->lock
1252 * held to prevent that a timer is enqueued in our queue via
1253 * the migration code. This does not affect enqueueing of
1254 * timers which run their callback and need to be requeued on
1257 cpu_base->expires_next.tv64 = KTIME_MAX;
1259 base = cpu_base->clock_base;
1261 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1263 struct timerqueue_node *node;
1265 basenow = ktime_add(now, base->offset);
1267 while ((node = timerqueue_getnext(&base->active))) {
1268 struct hrtimer *timer;
1270 timer = container_of(node, struct hrtimer, node);
1273 * The immediate goal for using the softexpires is
1274 * minimizing wakeups, not running timers at the
1275 * earliest interrupt after their soft expiration.
1276 * This allows us to avoid using a Priority Search
1277 * Tree, which can answer a stabbing querry for
1278 * overlapping intervals and instead use the simple
1279 * BST we already have.
1280 * We don't add extra wakeups by delaying timers that
1281 * are right-of a not yet expired timer, because that
1282 * timer will have to trigger a wakeup anyway.
1285 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1288 expires = ktime_sub(hrtimer_get_expires(timer),
1290 if (expires.tv64 < expires_next.tv64)
1291 expires_next = expires;
1295 __run_hrtimer(timer, &basenow);
1301 * Store the new expiry value so the migration code can verify
1304 cpu_base->expires_next = expires_next;
1305 raw_spin_unlock(&cpu_base->lock);
1307 /* Reprogramming necessary ? */
1308 if (expires_next.tv64 == KTIME_MAX ||
1309 !tick_program_event(expires_next, 0)) {
1310 cpu_base->hang_detected = 0;
1315 * The next timer was already expired due to:
1317 * - long lasting callbacks
1318 * - being scheduled away when running in a VM
1320 * We need to prevent that we loop forever in the hrtimer
1321 * interrupt routine. We give it 3 attempts to avoid
1322 * overreacting on some spurious event.
1325 cpu_base->nr_retries++;
1329 * Give the system a chance to do something else than looping
1330 * here. We stored the entry time, so we know exactly how long
1331 * we spent here. We schedule the next event this amount of
1334 cpu_base->nr_hangs++;
1335 cpu_base->hang_detected = 1;
1336 delta = ktime_sub(now, entry_time);
1337 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1338 cpu_base->max_hang_time = delta;
1340 * Limit it to a sensible value as we enforce a longer
1341 * delay. Give the CPU at least 100ms to catch up.
1343 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1344 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1346 expires_next = ktime_add(now, delta);
1347 tick_program_event(expires_next, 1);
1348 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1349 ktime_to_ns(delta));
1353 * local version of hrtimer_peek_ahead_timers() called with interrupts
1356 static void __hrtimer_peek_ahead_timers(void)
1358 struct tick_device *td;
1360 if (!hrtimer_hres_active())
1363 td = &__get_cpu_var(tick_cpu_device);
1364 if (td && td->evtdev)
1365 hrtimer_interrupt(td->evtdev);
1369 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1371 * hrtimer_peek_ahead_timers will peek at the timer queue of
1372 * the current cpu and check if there are any timers for which
1373 * the soft expires time has passed. If any such timers exist,
1374 * they are run immediately and then removed from the timer queue.
1377 void hrtimer_peek_ahead_timers(void)
1379 unsigned long flags;
1381 local_irq_save(flags);
1382 __hrtimer_peek_ahead_timers();
1383 local_irq_restore(flags);
1386 static void run_hrtimer_softirq(struct softirq_action *h)
1388 hrtimer_peek_ahead_timers();
1391 #else /* CONFIG_HIGH_RES_TIMERS */
1393 static inline void __hrtimer_peek_ahead_timers(void) { }
1395 #endif /* !CONFIG_HIGH_RES_TIMERS */
1398 * Called from timer softirq every jiffy, expire hrtimers:
1400 * For HRT its the fall back code to run the softirq in the timer
1401 * softirq context in case the hrtimer initialization failed or has
1402 * not been done yet.
1404 void hrtimer_run_pending(void)
1406 if (hrtimer_hres_active())
1410 * This _is_ ugly: We have to check in the softirq context,
1411 * whether we can switch to highres and / or nohz mode. The
1412 * clocksource switch happens in the timer interrupt with
1413 * xtime_lock held. Notification from there only sets the
1414 * check bit in the tick_oneshot code, otherwise we might
1415 * deadlock vs. xtime_lock.
1417 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1418 hrtimer_switch_to_hres();
1422 * Called from hardirq context every jiffy
1424 void hrtimer_run_queues(void)
1426 struct timerqueue_node *node;
1427 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1428 struct hrtimer_clock_base *base;
1429 int index, gettime = 1;
1431 if (hrtimer_hres_active())
1434 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1435 base = &cpu_base->clock_base[index];
1436 if (!timerqueue_getnext(&base->active))
1440 hrtimer_get_softirq_time(cpu_base);
1444 raw_spin_lock(&cpu_base->lock);
1446 while ((node = timerqueue_getnext(&base->active))) {
1447 struct hrtimer *timer;
1449 timer = container_of(node, struct hrtimer, node);
1450 if (base->softirq_time.tv64 <=
1451 hrtimer_get_expires_tv64(timer))
1454 __run_hrtimer(timer, &base->softirq_time);
1456 raw_spin_unlock(&cpu_base->lock);
1461 * Sleep related functions:
1463 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1465 struct hrtimer_sleeper *t =
1466 container_of(timer, struct hrtimer_sleeper, timer);
1467 struct task_struct *task = t->task;
1471 wake_up_process(task);
1473 return HRTIMER_NORESTART;
1476 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1478 sl->timer.function = hrtimer_wakeup;
1481 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1483 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1485 hrtimer_init_sleeper(t, current);
1488 set_current_state(TASK_INTERRUPTIBLE);
1489 hrtimer_start_expires(&t->timer, mode);
1490 if (!hrtimer_active(&t->timer))
1493 if (likely(t->task))
1496 hrtimer_cancel(&t->timer);
1497 mode = HRTIMER_MODE_ABS;
1499 } while (t->task && !signal_pending(current));
1501 __set_current_state(TASK_RUNNING);
1503 return t->task == NULL;
1506 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1508 struct timespec rmt;
1511 rem = hrtimer_expires_remaining(timer);
1514 rmt = ktime_to_timespec(rem);
1516 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1522 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1524 struct hrtimer_sleeper t;
1525 struct timespec __user *rmtp;
1528 hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
1530 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1532 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1535 rmtp = restart->nanosleep.rmtp;
1537 ret = update_rmtp(&t.timer, rmtp);
1542 /* The other values in restart are already filled in */
1543 ret = -ERESTART_RESTARTBLOCK;
1545 destroy_hrtimer_on_stack(&t.timer);
1549 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1550 const enum hrtimer_mode mode, const clockid_t clockid)
1552 struct restart_block *restart;
1553 struct hrtimer_sleeper t;
1555 unsigned long slack;
1557 slack = current->timer_slack_ns;
1558 if (rt_task(current))
1561 hrtimer_init_on_stack(&t.timer, clockid, mode);
1562 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1563 if (do_nanosleep(&t, mode))
1566 /* Absolute timers do not update the rmtp value and restart: */
1567 if (mode == HRTIMER_MODE_ABS) {
1568 ret = -ERESTARTNOHAND;
1573 ret = update_rmtp(&t.timer, rmtp);
1578 restart = ¤t_thread_info()->restart_block;
1579 restart->fn = hrtimer_nanosleep_restart;
1580 restart->nanosleep.index = t.timer.base->index;
1581 restart->nanosleep.rmtp = rmtp;
1582 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1584 ret = -ERESTART_RESTARTBLOCK;
1586 destroy_hrtimer_on_stack(&t.timer);
1590 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1591 struct timespec __user *, rmtp)
1595 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1598 if (!timespec_valid(&tu))
1601 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1605 * Functions related to boot-time initialization:
1607 static void __cpuinit init_hrtimers_cpu(int cpu)
1609 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1612 raw_spin_lock_init(&cpu_base->lock);
1614 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1615 cpu_base->clock_base[i].cpu_base = cpu_base;
1616 timerqueue_init_head(&cpu_base->clock_base[i].active);
1619 hrtimer_init_hres(cpu_base);
1622 #ifdef CONFIG_HOTPLUG_CPU
1624 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1625 struct hrtimer_clock_base *new_base)
1627 struct hrtimer *timer;
1628 struct timerqueue_node *node;
1630 while ((node = timerqueue_getnext(&old_base->active))) {
1631 timer = container_of(node, struct hrtimer, node);
1632 BUG_ON(hrtimer_callback_running(timer));
1633 debug_deactivate(timer);
1636 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1637 * timer could be seen as !active and just vanish away
1638 * under us on another CPU
1640 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1641 timer->base = new_base;
1643 * Enqueue the timers on the new cpu. This does not
1644 * reprogram the event device in case the timer
1645 * expires before the earliest on this CPU, but we run
1646 * hrtimer_interrupt after we migrated everything to
1647 * sort out already expired timers and reprogram the
1650 enqueue_hrtimer(timer, new_base);
1652 /* Clear the migration state bit */
1653 timer->state &= ~HRTIMER_STATE_MIGRATE;
1657 static void migrate_hrtimers(int scpu)
1659 struct hrtimer_cpu_base *old_base, *new_base;
1662 BUG_ON(cpu_online(scpu));
1663 tick_cancel_sched_timer(scpu);
1665 local_irq_disable();
1666 old_base = &per_cpu(hrtimer_bases, scpu);
1667 new_base = &__get_cpu_var(hrtimer_bases);
1669 * The caller is globally serialized and nobody else
1670 * takes two locks at once, deadlock is not possible.
1672 raw_spin_lock(&new_base->lock);
1673 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1675 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1676 migrate_hrtimer_list(&old_base->clock_base[i],
1677 &new_base->clock_base[i]);
1680 raw_spin_unlock(&old_base->lock);
1681 raw_spin_unlock(&new_base->lock);
1683 /* Check, if we got expired work to do */
1684 __hrtimer_peek_ahead_timers();
1688 #endif /* CONFIG_HOTPLUG_CPU */
1690 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1691 unsigned long action, void *hcpu)
1693 int scpu = (long)hcpu;
1697 case CPU_UP_PREPARE:
1698 case CPU_UP_PREPARE_FROZEN:
1699 init_hrtimers_cpu(scpu);
1702 #ifdef CONFIG_HOTPLUG_CPU
1704 case CPU_DYING_FROZEN:
1705 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1708 case CPU_DEAD_FROZEN:
1710 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1711 migrate_hrtimers(scpu);
1723 static struct notifier_block __cpuinitdata hrtimers_nb = {
1724 .notifier_call = hrtimer_cpu_notify,
1727 void __init hrtimers_init(void)
1729 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1730 (void *)(long)smp_processor_id());
1731 register_cpu_notifier(&hrtimers_nb);
1732 #ifdef CONFIG_HIGH_RES_TIMERS
1733 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1738 * schedule_hrtimeout_range_clock - sleep until timeout
1739 * @expires: timeout value (ktime_t)
1740 * @delta: slack in expires timeout (ktime_t)
1741 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1742 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1745 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1746 const enum hrtimer_mode mode, int clock)
1748 struct hrtimer_sleeper t;
1751 * Optimize when a zero timeout value is given. It does not
1752 * matter whether this is an absolute or a relative time.
1754 if (expires && !expires->tv64) {
1755 __set_current_state(TASK_RUNNING);
1760 * A NULL parameter means "infinite"
1764 __set_current_state(TASK_RUNNING);
1768 hrtimer_init_on_stack(&t.timer, clock, mode);
1769 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1771 hrtimer_init_sleeper(&t, current);
1773 hrtimer_start_expires(&t.timer, mode);
1774 if (!hrtimer_active(&t.timer))
1780 hrtimer_cancel(&t.timer);
1781 destroy_hrtimer_on_stack(&t.timer);
1783 __set_current_state(TASK_RUNNING);
1785 return !t.task ? 0 : -EINTR;
1789 * schedule_hrtimeout_range - sleep until timeout
1790 * @expires: timeout value (ktime_t)
1791 * @delta: slack in expires timeout (ktime_t)
1792 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1794 * Make the current task sleep until the given expiry time has
1795 * elapsed. The routine will return immediately unless
1796 * the current task state has been set (see set_current_state()).
1798 * The @delta argument gives the kernel the freedom to schedule the
1799 * actual wakeup to a time that is both power and performance friendly.
1800 * The kernel give the normal best effort behavior for "@expires+@delta",
1801 * but may decide to fire the timer earlier, but no earlier than @expires.
1803 * You can set the task state as follows -
1805 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1806 * pass before the routine returns.
1808 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1809 * delivered to the current task.
1811 * The current task state is guaranteed to be TASK_RUNNING when this
1814 * Returns 0 when the timer has expired otherwise -EINTR
1816 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1817 const enum hrtimer_mode mode)
1819 return schedule_hrtimeout_range_clock(expires, delta, mode,
1822 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1825 * schedule_hrtimeout - sleep until timeout
1826 * @expires: timeout value (ktime_t)
1827 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1829 * Make the current task sleep until the given expiry time has
1830 * elapsed. The routine will return immediately unless
1831 * the current task state has been set (see set_current_state()).
1833 * You can set the task state as follows -
1835 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1836 * pass before the routine returns.
1838 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1839 * delivered to the current task.
1841 * The current task state is guaranteed to be TASK_RUNNING when this
1844 * Returns 0 when the timer has expired otherwise -EINTR
1846 int __sched schedule_hrtimeout(ktime_t *expires,
1847 const enum hrtimer_mode mode)
1849 return schedule_hrtimeout_range(expires, 0, mode);
1851 EXPORT_SYMBOL_GPL(schedule_hrtimeout);