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 int hrtimer_clock_to_base_table[MAX_CLOCKS];
86 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
88 return hrtimer_clock_to_base_table[clock_id];
93 * Get the coarse grained time at the softirq based on xtime and
96 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
98 ktime_t xtim, mono, boot;
99 struct timespec xts, tom, slp;
101 get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
103 xtim = timespec_to_ktime(xts);
104 mono = ktime_add(xtim, timespec_to_ktime(tom));
105 boot = ktime_add(mono, timespec_to_ktime(slp));
106 base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
107 base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
108 base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
112 * Functions and macros which are different for UP/SMP systems are kept in a
118 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
119 * means that all timers which are tied to this base via timer->base are
120 * locked, and the base itself is locked too.
122 * So __run_timers/migrate_timers can safely modify all timers which could
123 * be found on the lists/queues.
125 * When the timer's base is locked, and the timer removed from list, it is
126 * possible to set timer->base = NULL and drop the lock: the timer remains
130 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
131 unsigned long *flags)
133 struct hrtimer_clock_base *base;
137 if (likely(base != NULL)) {
138 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
139 if (likely(base == timer->base))
141 /* The timer has migrated to another CPU: */
142 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
150 * Get the preferred target CPU for NOHZ
152 static int hrtimer_get_target(int this_cpu, int pinned)
155 if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
156 return get_nohz_timer_target();
162 * With HIGHRES=y we do not migrate the timer when it is expiring
163 * before the next event on the target cpu because we cannot reprogram
164 * the target cpu hardware and we would cause it to fire late.
166 * Called with cpu_base->lock of target cpu held.
169 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
171 #ifdef CONFIG_HIGH_RES_TIMERS
174 if (!new_base->cpu_base->hres_active)
177 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
178 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
185 * Switch the timer base to the current CPU when possible.
187 static inline struct hrtimer_clock_base *
188 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
191 struct hrtimer_clock_base *new_base;
192 struct hrtimer_cpu_base *new_cpu_base;
193 int this_cpu = smp_processor_id();
194 int cpu = hrtimer_get_target(this_cpu, pinned);
195 int basenum = hrtimer_clockid_to_base(base->index);
198 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
199 new_base = &new_cpu_base->clock_base[basenum];
201 if (base != new_base) {
203 * We are trying to move timer to new_base.
204 * However we can't change timer's base while it is running,
205 * so we keep it on the same CPU. No hassle vs. reprogramming
206 * the event source in the high resolution case. The softirq
207 * code will take care of this when the timer function has
208 * completed. There is no conflict as we hold the lock until
209 * the timer is enqueued.
211 if (unlikely(hrtimer_callback_running(timer)))
214 /* See the comment in lock_timer_base() */
216 raw_spin_unlock(&base->cpu_base->lock);
217 raw_spin_lock(&new_base->cpu_base->lock);
219 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
221 raw_spin_unlock(&new_base->cpu_base->lock);
222 raw_spin_lock(&base->cpu_base->lock);
226 timer->base = new_base;
231 #else /* CONFIG_SMP */
233 static inline struct hrtimer_clock_base *
234 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
236 struct hrtimer_clock_base *base = timer->base;
238 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
243 # define switch_hrtimer_base(t, b, p) (b)
245 #endif /* !CONFIG_SMP */
248 * Functions for the union type storage format of ktime_t which are
249 * too large for inlining:
251 #if BITS_PER_LONG < 64
252 # ifndef CONFIG_KTIME_SCALAR
254 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
256 * @nsec: the scalar nsec value to add
258 * Returns the sum of kt and nsec in ktime_t format
260 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
264 if (likely(nsec < NSEC_PER_SEC)) {
267 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
269 tmp = ktime_set((long)nsec, rem);
272 return ktime_add(kt, tmp);
275 EXPORT_SYMBOL_GPL(ktime_add_ns);
278 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
280 * @nsec: the scalar nsec value to subtract
282 * Returns the subtraction of @nsec from @kt in ktime_t format
284 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
288 if (likely(nsec < NSEC_PER_SEC)) {
291 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
293 tmp = ktime_set((long)nsec, rem);
296 return ktime_sub(kt, tmp);
299 EXPORT_SYMBOL_GPL(ktime_sub_ns);
300 # endif /* !CONFIG_KTIME_SCALAR */
303 * Divide a ktime value by a nanosecond value
305 u64 ktime_divns(const ktime_t kt, s64 div)
310 dclc = ktime_to_ns(kt);
311 /* Make sure the divisor is less than 2^32: */
317 do_div(dclc, (unsigned long) div);
321 #endif /* BITS_PER_LONG >= 64 */
324 * Add two ktime values and do a safety check for overflow:
326 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
328 ktime_t res = ktime_add(lhs, rhs);
331 * We use KTIME_SEC_MAX here, the maximum timeout which we can
332 * return to user space in a timespec:
334 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
335 res = ktime_set(KTIME_SEC_MAX, 0);
340 EXPORT_SYMBOL_GPL(ktime_add_safe);
342 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
344 static struct debug_obj_descr hrtimer_debug_descr;
347 * fixup_init is called when:
348 * - an active object is initialized
350 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
352 struct hrtimer *timer = addr;
355 case ODEBUG_STATE_ACTIVE:
356 hrtimer_cancel(timer);
357 debug_object_init(timer, &hrtimer_debug_descr);
365 * fixup_activate is called when:
366 * - an active object is activated
367 * - an unknown object is activated (might be a statically initialized object)
369 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
373 case ODEBUG_STATE_NOTAVAILABLE:
377 case ODEBUG_STATE_ACTIVE:
386 * fixup_free is called when:
387 * - an active object is freed
389 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
391 struct hrtimer *timer = addr;
394 case ODEBUG_STATE_ACTIVE:
395 hrtimer_cancel(timer);
396 debug_object_free(timer, &hrtimer_debug_descr);
403 static struct debug_obj_descr hrtimer_debug_descr = {
405 .fixup_init = hrtimer_fixup_init,
406 .fixup_activate = hrtimer_fixup_activate,
407 .fixup_free = hrtimer_fixup_free,
410 static inline void debug_hrtimer_init(struct hrtimer *timer)
412 debug_object_init(timer, &hrtimer_debug_descr);
415 static inline void debug_hrtimer_activate(struct hrtimer *timer)
417 debug_object_activate(timer, &hrtimer_debug_descr);
420 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
422 debug_object_deactivate(timer, &hrtimer_debug_descr);
425 static inline void debug_hrtimer_free(struct hrtimer *timer)
427 debug_object_free(timer, &hrtimer_debug_descr);
430 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
431 enum hrtimer_mode mode);
433 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
434 enum hrtimer_mode mode)
436 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
437 __hrtimer_init(timer, clock_id, mode);
439 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
441 void destroy_hrtimer_on_stack(struct hrtimer *timer)
443 debug_object_free(timer, &hrtimer_debug_descr);
447 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
448 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
449 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
453 debug_init(struct hrtimer *timer, clockid_t clockid,
454 enum hrtimer_mode mode)
456 debug_hrtimer_init(timer);
457 trace_hrtimer_init(timer, clockid, mode);
460 static inline void debug_activate(struct hrtimer *timer)
462 debug_hrtimer_activate(timer);
463 trace_hrtimer_start(timer);
466 static inline void debug_deactivate(struct hrtimer *timer)
468 debug_hrtimer_deactivate(timer);
469 trace_hrtimer_cancel(timer);
472 /* High resolution timer related functions */
473 #ifdef CONFIG_HIGH_RES_TIMERS
476 * High resolution timer enabled ?
478 static int hrtimer_hres_enabled __read_mostly = 1;
481 * Enable / Disable high resolution mode
483 static int __init setup_hrtimer_hres(char *str)
485 if (!strcmp(str, "off"))
486 hrtimer_hres_enabled = 0;
487 else if (!strcmp(str, "on"))
488 hrtimer_hres_enabled = 1;
494 __setup("highres=", setup_hrtimer_hres);
497 * hrtimer_high_res_enabled - query, if the highres mode is enabled
499 static inline int hrtimer_is_hres_enabled(void)
501 return hrtimer_hres_enabled;
505 * Is the high resolution mode active ?
507 static inline int hrtimer_hres_active(void)
509 return __this_cpu_read(hrtimer_bases.hres_active);
513 * Reprogram the event source with checking both queues for the
515 * Called with interrupts disabled and base->lock held
518 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
521 struct hrtimer_clock_base *base = cpu_base->clock_base;
522 ktime_t expires, expires_next;
524 expires_next.tv64 = KTIME_MAX;
526 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
527 struct hrtimer *timer;
528 struct timerqueue_node *next;
530 next = timerqueue_getnext(&base->active);
533 timer = container_of(next, struct hrtimer, node);
535 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
537 * clock_was_set() has changed base->offset so the
538 * result might be negative. Fix it up to prevent a
539 * false positive in clockevents_program_event()
541 if (expires.tv64 < 0)
543 if (expires.tv64 < expires_next.tv64)
544 expires_next = expires;
547 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
550 cpu_base->expires_next.tv64 = expires_next.tv64;
552 if (cpu_base->expires_next.tv64 != KTIME_MAX)
553 tick_program_event(cpu_base->expires_next, 1);
557 * Shared reprogramming for clock_realtime and clock_monotonic
559 * When a timer is enqueued and expires earlier than the already enqueued
560 * timers, we have to check, whether it expires earlier than the timer for
561 * which the clock event device was armed.
563 * Called with interrupts disabled and base->cpu_base.lock held
565 static int hrtimer_reprogram(struct hrtimer *timer,
566 struct hrtimer_clock_base *base)
568 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
569 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
572 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
575 * When the callback is running, we do not reprogram the clock event
576 * device. The timer callback is either running on a different CPU or
577 * the callback is executed in the hrtimer_interrupt context. The
578 * reprogramming is handled either by the softirq, which called the
579 * callback or at the end of the hrtimer_interrupt.
581 if (hrtimer_callback_running(timer))
585 * CLOCK_REALTIME timer might be requested with an absolute
586 * expiry time which is less than base->offset. Nothing wrong
587 * about that, just avoid to call into the tick code, which
588 * has now objections against negative expiry values.
590 if (expires.tv64 < 0)
593 if (expires.tv64 >= cpu_base->expires_next.tv64)
597 * If a hang was detected in the last timer interrupt then we
598 * do not schedule a timer which is earlier than the expiry
599 * which we enforced in the hang detection. We want the system
602 if (cpu_base->hang_detected)
606 * Clockevents returns -ETIME, when the event was in the past.
608 res = tick_program_event(expires, 0);
609 if (!IS_ERR_VALUE(res))
610 cpu_base->expires_next = expires;
616 * Retrigger next event is called after clock was set
618 * Called with interrupts disabled via on_each_cpu()
620 static void retrigger_next_event(void *arg)
622 struct hrtimer_cpu_base *base;
623 struct timespec realtime_offset, wtm, sleep;
625 if (!hrtimer_hres_active())
628 get_xtime_and_monotonic_and_sleep_offset(&realtime_offset, &wtm,
630 set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
632 base = &__get_cpu_var(hrtimer_bases);
634 /* Adjust CLOCK_REALTIME offset */
635 raw_spin_lock(&base->lock);
636 base->clock_base[HRTIMER_BASE_REALTIME].offset =
637 timespec_to_ktime(realtime_offset);
638 base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
639 timespec_to_ktime(sleep);
641 hrtimer_force_reprogram(base, 0);
642 raw_spin_unlock(&base->lock);
646 * Clock realtime was set
648 * Change the offset of the realtime clock vs. the monotonic
651 * We might have to reprogram the high resolution timer interrupt. On
652 * SMP we call the architecture specific code to retrigger _all_ high
653 * resolution timer interrupts. On UP we just disable interrupts and
654 * call the high resolution interrupt code.
656 void clock_was_set(void)
658 /* Retrigger the CPU local events everywhere */
659 on_each_cpu(retrigger_next_event, NULL, 1);
663 * During resume we might have to reprogram the high resolution timer
664 * interrupt (on the local CPU):
666 void hres_timers_resume(void)
668 WARN_ONCE(!irqs_disabled(),
669 KERN_INFO "hres_timers_resume() called with IRQs enabled!");
671 retrigger_next_event(NULL);
675 * Initialize the high resolution related parts of cpu_base
677 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
679 base->expires_next.tv64 = KTIME_MAX;
680 base->hres_active = 0;
684 * When High resolution timers are active, try to reprogram. Note, that in case
685 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
686 * check happens. The timer gets enqueued into the rbtree. The reprogramming
687 * and expiry check is done in the hrtimer_interrupt or in the softirq.
689 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
690 struct hrtimer_clock_base *base,
693 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
695 raw_spin_unlock(&base->cpu_base->lock);
696 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
697 raw_spin_lock(&base->cpu_base->lock);
699 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
708 * Switch to high resolution mode
710 static int hrtimer_switch_to_hres(void)
712 int cpu = smp_processor_id();
713 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
716 if (base->hres_active)
719 local_irq_save(flags);
721 if (tick_init_highres()) {
722 local_irq_restore(flags);
723 printk(KERN_WARNING "Could not switch to high resolution "
724 "mode on CPU %d\n", cpu);
727 base->hres_active = 1;
728 base->clock_base[HRTIMER_BASE_REALTIME].resolution = KTIME_HIGH_RES;
729 base->clock_base[HRTIMER_BASE_MONOTONIC].resolution = KTIME_HIGH_RES;
730 base->clock_base[HRTIMER_BASE_BOOTTIME].resolution = KTIME_HIGH_RES;
732 tick_setup_sched_timer();
734 /* "Retrigger" the interrupt to get things going */
735 retrigger_next_event(NULL);
736 local_irq_restore(flags);
742 static inline int hrtimer_hres_active(void) { return 0; }
743 static inline int hrtimer_is_hres_enabled(void) { return 0; }
744 static inline int hrtimer_switch_to_hres(void) { return 0; }
746 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
747 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
748 struct hrtimer_clock_base *base,
753 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
755 #endif /* CONFIG_HIGH_RES_TIMERS */
757 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
759 #ifdef CONFIG_TIMER_STATS
760 if (timer->start_site)
762 timer->start_site = __builtin_return_address(0);
763 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
764 timer->start_pid = current->pid;
768 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
770 #ifdef CONFIG_TIMER_STATS
771 timer->start_site = NULL;
775 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
777 #ifdef CONFIG_TIMER_STATS
778 if (likely(!timer_stats_active))
780 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
781 timer->function, timer->start_comm, 0);
786 * Counterpart to lock_hrtimer_base above:
789 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
791 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
795 * hrtimer_forward - forward the timer expiry
796 * @timer: hrtimer to forward
797 * @now: forward past this time
798 * @interval: the interval to forward
800 * Forward the timer expiry so it will expire in the future.
801 * Returns the number of overruns.
803 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
808 delta = ktime_sub(now, hrtimer_get_expires(timer));
813 if (interval.tv64 < timer->base->resolution.tv64)
814 interval.tv64 = timer->base->resolution.tv64;
816 if (unlikely(delta.tv64 >= interval.tv64)) {
817 s64 incr = ktime_to_ns(interval);
819 orun = ktime_divns(delta, incr);
820 hrtimer_add_expires_ns(timer, incr * orun);
821 if (hrtimer_get_expires_tv64(timer) > now.tv64)
824 * This (and the ktime_add() below) is the
825 * correction for exact:
829 hrtimer_add_expires(timer, interval);
833 EXPORT_SYMBOL_GPL(hrtimer_forward);
836 * enqueue_hrtimer - internal function to (re)start a timer
838 * The timer is inserted in expiry order. Insertion into the
839 * red black tree is O(log(n)). Must hold the base lock.
841 * Returns 1 when the new timer is the leftmost timer in the tree.
843 static int enqueue_hrtimer(struct hrtimer *timer,
844 struct hrtimer_clock_base *base)
846 debug_activate(timer);
848 timerqueue_add(&base->active, &timer->node);
851 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
852 * state of a possibly running callback.
854 timer->state |= HRTIMER_STATE_ENQUEUED;
856 return (&timer->node == base->active.next);
860 * __remove_hrtimer - internal function to remove a timer
862 * Caller must hold the base lock.
864 * High resolution timer mode reprograms the clock event device when the
865 * timer is the one which expires next. The caller can disable this by setting
866 * reprogram to zero. This is useful, when the context does a reprogramming
867 * anyway (e.g. timer interrupt)
869 static void __remove_hrtimer(struct hrtimer *timer,
870 struct hrtimer_clock_base *base,
871 unsigned long newstate, int reprogram)
873 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
876 if (&timer->node == timerqueue_getnext(&base->active)) {
877 #ifdef CONFIG_HIGH_RES_TIMERS
878 /* Reprogram the clock event device. if enabled */
879 if (reprogram && hrtimer_hres_active()) {
882 expires = ktime_sub(hrtimer_get_expires(timer),
884 if (base->cpu_base->expires_next.tv64 == expires.tv64)
885 hrtimer_force_reprogram(base->cpu_base, 1);
889 timerqueue_del(&base->active, &timer->node);
891 timer->state = newstate;
895 * remove hrtimer, called with base lock held
898 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
900 if (hrtimer_is_queued(timer)) {
905 * Remove the timer and force reprogramming when high
906 * resolution mode is active and the timer is on the current
907 * CPU. If we remove a timer on another CPU, reprogramming is
908 * skipped. The interrupt event on this CPU is fired and
909 * reprogramming happens in the interrupt handler. This is a
910 * rare case and less expensive than a smp call.
912 debug_deactivate(timer);
913 timer_stats_hrtimer_clear_start_info(timer);
914 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
916 * We must preserve the CALLBACK state flag here,
917 * otherwise we could move the timer base in
918 * switch_hrtimer_base.
920 state = timer->state & HRTIMER_STATE_CALLBACK;
921 __remove_hrtimer(timer, base, state, reprogram);
927 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
928 unsigned long delta_ns, const enum hrtimer_mode mode,
931 struct hrtimer_clock_base *base, *new_base;
935 base = lock_hrtimer_base(timer, &flags);
937 /* Remove an active timer from the queue: */
938 ret = remove_hrtimer(timer, base);
940 /* Switch the timer base, if necessary: */
941 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
943 if (mode & HRTIMER_MODE_REL) {
944 tim = ktime_add_safe(tim, new_base->get_time());
946 * CONFIG_TIME_LOW_RES is a temporary way for architectures
947 * to signal that they simply return xtime in
948 * do_gettimeoffset(). In this case we want to round up by
949 * resolution when starting a relative timer, to avoid short
950 * timeouts. This will go away with the GTOD framework.
952 #ifdef CONFIG_TIME_LOW_RES
953 tim = ktime_add_safe(tim, base->resolution);
957 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
959 timer_stats_hrtimer_set_start_info(timer);
961 leftmost = enqueue_hrtimer(timer, new_base);
964 * Only allow reprogramming if the new base is on this CPU.
965 * (it might still be on another CPU if the timer was pending)
967 * XXX send_remote_softirq() ?
969 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
970 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
972 unlock_hrtimer_base(timer, &flags);
978 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
979 * @timer: the timer to be added
981 * @delta_ns: "slack" range for the timer
982 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
986 * 1 when the timer was active
988 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
989 unsigned long delta_ns, const enum hrtimer_mode mode)
991 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
993 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
996 * hrtimer_start - (re)start an hrtimer on the current CPU
997 * @timer: the timer to be added
999 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1003 * 1 when the timer was active
1006 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1008 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1010 EXPORT_SYMBOL_GPL(hrtimer_start);
1014 * hrtimer_try_to_cancel - try to deactivate a timer
1015 * @timer: hrtimer to stop
1018 * 0 when the timer was not active
1019 * 1 when the timer was active
1020 * -1 when the timer is currently excuting the callback function and
1023 int hrtimer_try_to_cancel(struct hrtimer *timer)
1025 struct hrtimer_clock_base *base;
1026 unsigned long flags;
1029 base = lock_hrtimer_base(timer, &flags);
1031 if (!hrtimer_callback_running(timer))
1032 ret = remove_hrtimer(timer, base);
1034 unlock_hrtimer_base(timer, &flags);
1039 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1042 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1043 * @timer: the timer to be cancelled
1046 * 0 when the timer was not active
1047 * 1 when the timer was active
1049 int hrtimer_cancel(struct hrtimer *timer)
1052 int ret = hrtimer_try_to_cancel(timer);
1059 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1062 * hrtimer_get_remaining - get remaining time for the timer
1063 * @timer: the timer to read
1065 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1067 unsigned long flags;
1070 lock_hrtimer_base(timer, &flags);
1071 rem = hrtimer_expires_remaining(timer);
1072 unlock_hrtimer_base(timer, &flags);
1076 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1080 * hrtimer_get_next_event - get the time until next expiry event
1082 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1085 ktime_t hrtimer_get_next_event(void)
1087 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1088 struct hrtimer_clock_base *base = cpu_base->clock_base;
1089 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1090 unsigned long flags;
1093 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1095 if (!hrtimer_hres_active()) {
1096 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1097 struct hrtimer *timer;
1098 struct timerqueue_node *next;
1100 next = timerqueue_getnext(&base->active);
1104 timer = container_of(next, struct hrtimer, node);
1105 delta.tv64 = hrtimer_get_expires_tv64(timer);
1106 delta = ktime_sub(delta, base->get_time());
1107 if (delta.tv64 < mindelta.tv64)
1108 mindelta.tv64 = delta.tv64;
1112 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1114 if (mindelta.tv64 < 0)
1120 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1121 enum hrtimer_mode mode)
1123 struct hrtimer_cpu_base *cpu_base;
1126 memset(timer, 0, sizeof(struct hrtimer));
1128 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1130 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1131 clock_id = CLOCK_MONOTONIC;
1133 base = hrtimer_clockid_to_base(clock_id);
1134 timer->base = &cpu_base->clock_base[base];
1135 timerqueue_init(&timer->node);
1137 #ifdef CONFIG_TIMER_STATS
1138 timer->start_site = NULL;
1139 timer->start_pid = -1;
1140 memset(timer->start_comm, 0, TASK_COMM_LEN);
1145 * hrtimer_init - initialize a timer to the given clock
1146 * @timer: the timer to be initialized
1147 * @clock_id: the clock to be used
1148 * @mode: timer mode abs/rel
1150 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1151 enum hrtimer_mode mode)
1153 debug_init(timer, clock_id, mode);
1154 __hrtimer_init(timer, clock_id, mode);
1156 EXPORT_SYMBOL_GPL(hrtimer_init);
1159 * hrtimer_get_res - get the timer resolution for a clock
1160 * @which_clock: which clock to query
1161 * @tp: pointer to timespec variable to store the resolution
1163 * Store the resolution of the clock selected by @which_clock in the
1164 * variable pointed to by @tp.
1166 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1168 struct hrtimer_cpu_base *cpu_base;
1169 int base = hrtimer_clockid_to_base(which_clock);
1171 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1172 *tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
1176 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1178 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1180 struct hrtimer_clock_base *base = timer->base;
1181 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1182 enum hrtimer_restart (*fn)(struct hrtimer *);
1185 WARN_ON(!irqs_disabled());
1187 debug_deactivate(timer);
1188 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1189 timer_stats_account_hrtimer(timer);
1190 fn = timer->function;
1193 * Because we run timers from hardirq context, there is no chance
1194 * they get migrated to another cpu, therefore its safe to unlock
1197 raw_spin_unlock(&cpu_base->lock);
1198 trace_hrtimer_expire_entry(timer, now);
1199 restart = fn(timer);
1200 trace_hrtimer_expire_exit(timer);
1201 raw_spin_lock(&cpu_base->lock);
1204 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1205 * we do not reprogramm the event hardware. Happens either in
1206 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1208 if (restart != HRTIMER_NORESTART) {
1209 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1210 enqueue_hrtimer(timer, base);
1213 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1215 timer->state &= ~HRTIMER_STATE_CALLBACK;
1218 #ifdef CONFIG_HIGH_RES_TIMERS
1221 * High resolution timer interrupt
1222 * Called with interrupts disabled
1224 void hrtimer_interrupt(struct clock_event_device *dev)
1226 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1227 struct hrtimer_clock_base *base;
1228 ktime_t expires_next, now, entry_time, delta;
1231 BUG_ON(!cpu_base->hres_active);
1232 cpu_base->nr_events++;
1233 dev->next_event.tv64 = KTIME_MAX;
1235 entry_time = now = ktime_get();
1237 expires_next.tv64 = KTIME_MAX;
1239 raw_spin_lock(&cpu_base->lock);
1241 * We set expires_next to KTIME_MAX here with cpu_base->lock
1242 * held to prevent that a timer is enqueued in our queue via
1243 * the migration code. This does not affect enqueueing of
1244 * timers which run their callback and need to be requeued on
1247 cpu_base->expires_next.tv64 = KTIME_MAX;
1249 base = cpu_base->clock_base;
1251 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1253 struct timerqueue_node *node;
1255 basenow = ktime_add(now, base->offset);
1257 while ((node = timerqueue_getnext(&base->active))) {
1258 struct hrtimer *timer;
1260 timer = container_of(node, struct hrtimer, node);
1263 * The immediate goal for using the softexpires is
1264 * minimizing wakeups, not running timers at the
1265 * earliest interrupt after their soft expiration.
1266 * This allows us to avoid using a Priority Search
1267 * Tree, which can answer a stabbing querry for
1268 * overlapping intervals and instead use the simple
1269 * BST we already have.
1270 * We don't add extra wakeups by delaying timers that
1271 * are right-of a not yet expired timer, because that
1272 * timer will have to trigger a wakeup anyway.
1275 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1278 expires = ktime_sub(hrtimer_get_expires(timer),
1280 if (expires.tv64 < expires_next.tv64)
1281 expires_next = expires;
1285 __run_hrtimer(timer, &basenow);
1291 * Store the new expiry value so the migration code can verify
1294 cpu_base->expires_next = expires_next;
1295 raw_spin_unlock(&cpu_base->lock);
1297 /* Reprogramming necessary ? */
1298 if (expires_next.tv64 == KTIME_MAX ||
1299 !tick_program_event(expires_next, 0)) {
1300 cpu_base->hang_detected = 0;
1305 * The next timer was already expired due to:
1307 * - long lasting callbacks
1308 * - being scheduled away when running in a VM
1310 * We need to prevent that we loop forever in the hrtimer
1311 * interrupt routine. We give it 3 attempts to avoid
1312 * overreacting on some spurious event.
1315 cpu_base->nr_retries++;
1319 * Give the system a chance to do something else than looping
1320 * here. We stored the entry time, so we know exactly how long
1321 * we spent here. We schedule the next event this amount of
1324 cpu_base->nr_hangs++;
1325 cpu_base->hang_detected = 1;
1326 delta = ktime_sub(now, entry_time);
1327 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1328 cpu_base->max_hang_time = delta;
1330 * Limit it to a sensible value as we enforce a longer
1331 * delay. Give the CPU at least 100ms to catch up.
1333 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1334 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1336 expires_next = ktime_add(now, delta);
1337 tick_program_event(expires_next, 1);
1338 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1339 ktime_to_ns(delta));
1343 * local version of hrtimer_peek_ahead_timers() called with interrupts
1346 static void __hrtimer_peek_ahead_timers(void)
1348 struct tick_device *td;
1350 if (!hrtimer_hres_active())
1353 td = &__get_cpu_var(tick_cpu_device);
1354 if (td && td->evtdev)
1355 hrtimer_interrupt(td->evtdev);
1359 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1361 * hrtimer_peek_ahead_timers will peek at the timer queue of
1362 * the current cpu and check if there are any timers for which
1363 * the soft expires time has passed. If any such timers exist,
1364 * they are run immediately and then removed from the timer queue.
1367 void hrtimer_peek_ahead_timers(void)
1369 unsigned long flags;
1371 local_irq_save(flags);
1372 __hrtimer_peek_ahead_timers();
1373 local_irq_restore(flags);
1376 static void run_hrtimer_softirq(struct softirq_action *h)
1378 hrtimer_peek_ahead_timers();
1381 #else /* CONFIG_HIGH_RES_TIMERS */
1383 static inline void __hrtimer_peek_ahead_timers(void) { }
1385 #endif /* !CONFIG_HIGH_RES_TIMERS */
1388 * Called from timer softirq every jiffy, expire hrtimers:
1390 * For HRT its the fall back code to run the softirq in the timer
1391 * softirq context in case the hrtimer initialization failed or has
1392 * not been done yet.
1394 void hrtimer_run_pending(void)
1396 if (hrtimer_hres_active())
1400 * This _is_ ugly: We have to check in the softirq context,
1401 * whether we can switch to highres and / or nohz mode. The
1402 * clocksource switch happens in the timer interrupt with
1403 * xtime_lock held. Notification from there only sets the
1404 * check bit in the tick_oneshot code, otherwise we might
1405 * deadlock vs. xtime_lock.
1407 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1408 hrtimer_switch_to_hres();
1412 * Called from hardirq context every jiffy
1414 void hrtimer_run_queues(void)
1416 struct timerqueue_node *node;
1417 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1418 struct hrtimer_clock_base *base;
1419 int index, gettime = 1;
1421 if (hrtimer_hres_active())
1424 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1425 base = &cpu_base->clock_base[index];
1426 if (!timerqueue_getnext(&base->active))
1430 hrtimer_get_softirq_time(cpu_base);
1434 raw_spin_lock(&cpu_base->lock);
1436 while ((node = timerqueue_getnext(&base->active))) {
1437 struct hrtimer *timer;
1439 timer = container_of(node, struct hrtimer, node);
1440 if (base->softirq_time.tv64 <=
1441 hrtimer_get_expires_tv64(timer))
1444 __run_hrtimer(timer, &base->softirq_time);
1446 raw_spin_unlock(&cpu_base->lock);
1451 * Sleep related functions:
1453 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1455 struct hrtimer_sleeper *t =
1456 container_of(timer, struct hrtimer_sleeper, timer);
1457 struct task_struct *task = t->task;
1461 wake_up_process(task);
1463 return HRTIMER_NORESTART;
1466 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1468 sl->timer.function = hrtimer_wakeup;
1471 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1473 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1475 hrtimer_init_sleeper(t, current);
1478 set_current_state(TASK_INTERRUPTIBLE);
1479 hrtimer_start_expires(&t->timer, mode);
1480 if (!hrtimer_active(&t->timer))
1483 if (likely(t->task))
1486 hrtimer_cancel(&t->timer);
1487 mode = HRTIMER_MODE_ABS;
1489 } while (t->task && !signal_pending(current));
1491 __set_current_state(TASK_RUNNING);
1493 return t->task == NULL;
1496 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1498 struct timespec rmt;
1501 rem = hrtimer_expires_remaining(timer);
1504 rmt = ktime_to_timespec(rem);
1506 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1512 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1514 struct hrtimer_sleeper t;
1515 struct timespec __user *rmtp;
1518 hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
1520 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1522 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1525 rmtp = restart->nanosleep.rmtp;
1527 ret = update_rmtp(&t.timer, rmtp);
1532 /* The other values in restart are already filled in */
1533 ret = -ERESTART_RESTARTBLOCK;
1535 destroy_hrtimer_on_stack(&t.timer);
1539 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1540 const enum hrtimer_mode mode, const clockid_t clockid)
1542 struct restart_block *restart;
1543 struct hrtimer_sleeper t;
1545 unsigned long slack;
1547 slack = current->timer_slack_ns;
1548 if (rt_task(current))
1551 hrtimer_init_on_stack(&t.timer, clockid, mode);
1552 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1553 if (do_nanosleep(&t, mode))
1556 /* Absolute timers do not update the rmtp value and restart: */
1557 if (mode == HRTIMER_MODE_ABS) {
1558 ret = -ERESTARTNOHAND;
1563 ret = update_rmtp(&t.timer, rmtp);
1568 restart = ¤t_thread_info()->restart_block;
1569 restart->fn = hrtimer_nanosleep_restart;
1570 restart->nanosleep.index = t.timer.base->index;
1571 restart->nanosleep.rmtp = rmtp;
1572 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1574 ret = -ERESTART_RESTARTBLOCK;
1576 destroy_hrtimer_on_stack(&t.timer);
1580 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1581 struct timespec __user *, rmtp)
1585 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1588 if (!timespec_valid(&tu))
1591 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1595 * Functions related to boot-time initialization:
1597 static void __cpuinit init_hrtimers_cpu(int cpu)
1599 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1602 raw_spin_lock_init(&cpu_base->lock);
1604 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1605 cpu_base->clock_base[i].cpu_base = cpu_base;
1606 timerqueue_init_head(&cpu_base->clock_base[i].active);
1609 hrtimer_init_hres(cpu_base);
1612 #ifdef CONFIG_HOTPLUG_CPU
1614 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1615 struct hrtimer_clock_base *new_base)
1617 struct hrtimer *timer;
1618 struct timerqueue_node *node;
1620 while ((node = timerqueue_getnext(&old_base->active))) {
1621 timer = container_of(node, struct hrtimer, node);
1622 BUG_ON(hrtimer_callback_running(timer));
1623 debug_deactivate(timer);
1626 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1627 * timer could be seen as !active and just vanish away
1628 * under us on another CPU
1630 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1631 timer->base = new_base;
1633 * Enqueue the timers on the new cpu. This does not
1634 * reprogram the event device in case the timer
1635 * expires before the earliest on this CPU, but we run
1636 * hrtimer_interrupt after we migrated everything to
1637 * sort out already expired timers and reprogram the
1640 enqueue_hrtimer(timer, new_base);
1642 /* Clear the migration state bit */
1643 timer->state &= ~HRTIMER_STATE_MIGRATE;
1647 static void migrate_hrtimers(int scpu)
1649 struct hrtimer_cpu_base *old_base, *new_base;
1652 BUG_ON(cpu_online(scpu));
1653 tick_cancel_sched_timer(scpu);
1655 local_irq_disable();
1656 old_base = &per_cpu(hrtimer_bases, scpu);
1657 new_base = &__get_cpu_var(hrtimer_bases);
1659 * The caller is globally serialized and nobody else
1660 * takes two locks at once, deadlock is not possible.
1662 raw_spin_lock(&new_base->lock);
1663 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1665 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1666 migrate_hrtimer_list(&old_base->clock_base[i],
1667 &new_base->clock_base[i]);
1670 raw_spin_unlock(&old_base->lock);
1671 raw_spin_unlock(&new_base->lock);
1673 /* Check, if we got expired work to do */
1674 __hrtimer_peek_ahead_timers();
1678 #endif /* CONFIG_HOTPLUG_CPU */
1680 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1681 unsigned long action, void *hcpu)
1683 int scpu = (long)hcpu;
1687 case CPU_UP_PREPARE:
1688 case CPU_UP_PREPARE_FROZEN:
1689 init_hrtimers_cpu(scpu);
1692 #ifdef CONFIG_HOTPLUG_CPU
1694 case CPU_DYING_FROZEN:
1695 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1698 case CPU_DEAD_FROZEN:
1700 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1701 migrate_hrtimers(scpu);
1713 static struct notifier_block __cpuinitdata hrtimers_nb = {
1714 .notifier_call = hrtimer_cpu_notify,
1717 void __init hrtimers_init(void)
1719 hrtimer_clock_to_base_table[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME;
1720 hrtimer_clock_to_base_table[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC;
1721 hrtimer_clock_to_base_table[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME;
1723 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1724 (void *)(long)smp_processor_id());
1725 register_cpu_notifier(&hrtimers_nb);
1726 #ifdef CONFIG_HIGH_RES_TIMERS
1727 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1732 * schedule_hrtimeout_range_clock - sleep until timeout
1733 * @expires: timeout value (ktime_t)
1734 * @delta: slack in expires timeout (ktime_t)
1735 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1736 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1739 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1740 const enum hrtimer_mode mode, int clock)
1742 struct hrtimer_sleeper t;
1745 * Optimize when a zero timeout value is given. It does not
1746 * matter whether this is an absolute or a relative time.
1748 if (expires && !expires->tv64) {
1749 __set_current_state(TASK_RUNNING);
1754 * A NULL parameter means "infinite"
1758 __set_current_state(TASK_RUNNING);
1762 hrtimer_init_on_stack(&t.timer, clock, mode);
1763 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1765 hrtimer_init_sleeper(&t, current);
1767 hrtimer_start_expires(&t.timer, mode);
1768 if (!hrtimer_active(&t.timer))
1774 hrtimer_cancel(&t.timer);
1775 destroy_hrtimer_on_stack(&t.timer);
1777 __set_current_state(TASK_RUNNING);
1779 return !t.task ? 0 : -EINTR;
1783 * schedule_hrtimeout_range - sleep until timeout
1784 * @expires: timeout value (ktime_t)
1785 * @delta: slack in expires timeout (ktime_t)
1786 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1788 * Make the current task sleep until the given expiry time has
1789 * elapsed. The routine will return immediately unless
1790 * the current task state has been set (see set_current_state()).
1792 * The @delta argument gives the kernel the freedom to schedule the
1793 * actual wakeup to a time that is both power and performance friendly.
1794 * The kernel give the normal best effort behavior for "@expires+@delta",
1795 * but may decide to fire the timer earlier, but no earlier than @expires.
1797 * You can set the task state as follows -
1799 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1800 * pass before the routine returns.
1802 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1803 * delivered to the current task.
1805 * The current task state is guaranteed to be TASK_RUNNING when this
1808 * Returns 0 when the timer has expired otherwise -EINTR
1810 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1811 const enum hrtimer_mode mode)
1813 return schedule_hrtimeout_range_clock(expires, delta, mode,
1816 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1819 * schedule_hrtimeout - sleep until timeout
1820 * @expires: timeout value (ktime_t)
1821 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1823 * Make the current task sleep until the given expiry time has
1824 * elapsed. The routine will return immediately unless
1825 * the current task state has been set (see set_current_state()).
1827 * You can set the task state as follows -
1829 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1830 * pass before the routine returns.
1832 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1833 * delivered to the current task.
1835 * The current task state is guaranteed to be TASK_RUNNING when this
1838 * Returns 0 when the timer has expired otherwise -EINTR
1840 int __sched schedule_hrtimeout(ktime_t *expires,
1841 const enum hrtimer_mode mode)
1843 return schedule_hrtimeout_range(expires, 0, mode);
1845 EXPORT_SYMBOL_GPL(schedule_hrtimeout);