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 * Note: If we want to add new timer bases, we have to skip the two
57 * clock ids captured by the cpu-timers. We do this by holding empty
58 * entries rather than doing math adjustment of the clock ids.
59 * This ensures that we capture erroneous accesses to these clock ids
60 * rather than moving them into the range of valid clock id's.
62 DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
68 .index = CLOCK_REALTIME,
69 .get_time = &ktime_get_real,
70 .resolution = KTIME_LOW_RES,
73 .index = CLOCK_MONOTONIC,
74 .get_time = &ktime_get,
75 .resolution = KTIME_LOW_RES,
81 * Get the coarse grained time at the softirq based on xtime and
84 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
87 struct timespec xts, tom;
91 seq = read_seqbegin(&xtime_lock);
92 xts = __current_kernel_time();
93 tom = __get_wall_to_monotonic();
94 } while (read_seqretry(&xtime_lock, seq));
96 xtim = timespec_to_ktime(xts);
97 tomono = timespec_to_ktime(tom);
98 base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
99 base->clock_base[CLOCK_MONOTONIC].softirq_time =
100 ktime_add(xtim, tomono);
104 * Functions and macros which are different for UP/SMP systems are kept in a
110 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
111 * means that all timers which are tied to this base via timer->base are
112 * locked, and the base itself is locked too.
114 * So __run_timers/migrate_timers can safely modify all timers which could
115 * be found on the lists/queues.
117 * When the timer's base is locked, and the timer removed from list, it is
118 * possible to set timer->base = NULL and drop the lock: the timer remains
122 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
123 unsigned long *flags)
125 struct hrtimer_clock_base *base;
129 if (likely(base != NULL)) {
130 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
131 if (likely(base == timer->base))
133 /* The timer has migrated to another CPU: */
134 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
142 * Get the preferred target CPU for NOHZ
144 static int hrtimer_get_target(int this_cpu, int pinned)
147 if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) {
148 int preferred_cpu = get_nohz_load_balancer();
150 if (preferred_cpu >= 0)
151 return preferred_cpu;
158 * With HIGHRES=y we do not migrate the timer when it is expiring
159 * before the next event on the target cpu because we cannot reprogram
160 * the target cpu hardware and we would cause it to fire late.
162 * Called with cpu_base->lock of target cpu held.
165 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
167 #ifdef CONFIG_HIGH_RES_TIMERS
170 if (!new_base->cpu_base->hres_active)
173 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
174 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
181 * Switch the timer base to the current CPU when possible.
183 static inline struct hrtimer_clock_base *
184 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
187 struct hrtimer_clock_base *new_base;
188 struct hrtimer_cpu_base *new_cpu_base;
189 int this_cpu = smp_processor_id();
190 int cpu = hrtimer_get_target(this_cpu, pinned);
193 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
194 new_base = &new_cpu_base->clock_base[base->index];
196 if (base != new_base) {
198 * We are trying to move timer to new_base.
199 * However we can't change timer's base while it is running,
200 * so we keep it on the same CPU. No hassle vs. reprogramming
201 * the event source in the high resolution case. The softirq
202 * code will take care of this when the timer function has
203 * completed. There is no conflict as we hold the lock until
204 * the timer is enqueued.
206 if (unlikely(hrtimer_callback_running(timer)))
209 /* See the comment in lock_timer_base() */
211 raw_spin_unlock(&base->cpu_base->lock);
212 raw_spin_lock(&new_base->cpu_base->lock);
214 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
216 raw_spin_unlock(&new_base->cpu_base->lock);
217 raw_spin_lock(&base->cpu_base->lock);
221 timer->base = new_base;
226 #else /* CONFIG_SMP */
228 static inline struct hrtimer_clock_base *
229 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
231 struct hrtimer_clock_base *base = timer->base;
233 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
238 # define switch_hrtimer_base(t, b, p) (b)
240 #endif /* !CONFIG_SMP */
243 * Functions for the union type storage format of ktime_t which are
244 * too large for inlining:
246 #if BITS_PER_LONG < 64
247 # ifndef CONFIG_KTIME_SCALAR
249 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
251 * @nsec: the scalar nsec value to add
253 * Returns the sum of kt and nsec in ktime_t format
255 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
259 if (likely(nsec < NSEC_PER_SEC)) {
262 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
264 tmp = ktime_set((long)nsec, rem);
267 return ktime_add(kt, tmp);
270 EXPORT_SYMBOL_GPL(ktime_add_ns);
273 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
275 * @nsec: the scalar nsec value to subtract
277 * Returns the subtraction of @nsec from @kt in ktime_t format
279 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
283 if (likely(nsec < NSEC_PER_SEC)) {
286 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
288 tmp = ktime_set((long)nsec, rem);
291 return ktime_sub(kt, tmp);
294 EXPORT_SYMBOL_GPL(ktime_sub_ns);
295 # endif /* !CONFIG_KTIME_SCALAR */
298 * Divide a ktime value by a nanosecond value
300 u64 ktime_divns(const ktime_t kt, s64 div)
305 dclc = ktime_to_ns(kt);
306 /* Make sure the divisor is less than 2^32: */
312 do_div(dclc, (unsigned long) div);
316 #endif /* BITS_PER_LONG >= 64 */
319 * Add two ktime values and do a safety check for overflow:
321 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
323 ktime_t res = ktime_add(lhs, rhs);
326 * We use KTIME_SEC_MAX here, the maximum timeout which we can
327 * return to user space in a timespec:
329 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
330 res = ktime_set(KTIME_SEC_MAX, 0);
335 EXPORT_SYMBOL_GPL(ktime_add_safe);
337 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
339 static struct debug_obj_descr hrtimer_debug_descr;
342 * fixup_init is called when:
343 * - an active object is initialized
345 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
347 struct hrtimer *timer = addr;
350 case ODEBUG_STATE_ACTIVE:
351 hrtimer_cancel(timer);
352 debug_object_init(timer, &hrtimer_debug_descr);
360 * fixup_activate is called when:
361 * - an active object is activated
362 * - an unknown object is activated (might be a statically initialized object)
364 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
368 case ODEBUG_STATE_NOTAVAILABLE:
372 case ODEBUG_STATE_ACTIVE:
381 * fixup_free is called when:
382 * - an active object is freed
384 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
386 struct hrtimer *timer = addr;
389 case ODEBUG_STATE_ACTIVE:
390 hrtimer_cancel(timer);
391 debug_object_free(timer, &hrtimer_debug_descr);
398 static struct debug_obj_descr hrtimer_debug_descr = {
400 .fixup_init = hrtimer_fixup_init,
401 .fixup_activate = hrtimer_fixup_activate,
402 .fixup_free = hrtimer_fixup_free,
405 static inline void debug_hrtimer_init(struct hrtimer *timer)
407 debug_object_init(timer, &hrtimer_debug_descr);
410 static inline void debug_hrtimer_activate(struct hrtimer *timer)
412 debug_object_activate(timer, &hrtimer_debug_descr);
415 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
417 debug_object_deactivate(timer, &hrtimer_debug_descr);
420 static inline void debug_hrtimer_free(struct hrtimer *timer)
422 debug_object_free(timer, &hrtimer_debug_descr);
425 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
426 enum hrtimer_mode mode);
428 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
429 enum hrtimer_mode mode)
431 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
432 __hrtimer_init(timer, clock_id, mode);
434 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
436 void destroy_hrtimer_on_stack(struct hrtimer *timer)
438 debug_object_free(timer, &hrtimer_debug_descr);
442 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
443 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
444 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
448 debug_init(struct hrtimer *timer, clockid_t clockid,
449 enum hrtimer_mode mode)
451 debug_hrtimer_init(timer);
452 trace_hrtimer_init(timer, clockid, mode);
455 static inline void debug_activate(struct hrtimer *timer)
457 debug_hrtimer_activate(timer);
458 trace_hrtimer_start(timer);
461 static inline void debug_deactivate(struct hrtimer *timer)
463 debug_hrtimer_deactivate(timer);
464 trace_hrtimer_cancel(timer);
467 /* High resolution timer related functions */
468 #ifdef CONFIG_HIGH_RES_TIMERS
471 * High resolution timer enabled ?
473 static int hrtimer_hres_enabled __read_mostly = 1;
476 * Enable / Disable high resolution mode
478 static int __init setup_hrtimer_hres(char *str)
480 if (!strcmp(str, "off"))
481 hrtimer_hres_enabled = 0;
482 else if (!strcmp(str, "on"))
483 hrtimer_hres_enabled = 1;
489 __setup("highres=", setup_hrtimer_hres);
492 * hrtimer_high_res_enabled - query, if the highres mode is enabled
494 static inline int hrtimer_is_hres_enabled(void)
496 return hrtimer_hres_enabled;
500 * Is the high resolution mode active ?
502 static inline int hrtimer_hres_active(void)
504 return __get_cpu_var(hrtimer_bases).hres_active;
508 * Reprogram the event source with checking both queues for the
510 * Called with interrupts disabled and base->lock held
513 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
516 struct hrtimer_clock_base *base = cpu_base->clock_base;
517 ktime_t expires, expires_next;
519 expires_next.tv64 = KTIME_MAX;
521 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
522 struct hrtimer *timer;
526 timer = rb_entry(base->first, struct hrtimer, node);
527 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
529 * clock_was_set() has changed base->offset so the
530 * result might be negative. Fix it up to prevent a
531 * false positive in clockevents_program_event()
533 if (expires.tv64 < 0)
535 if (expires.tv64 < expires_next.tv64)
536 expires_next = expires;
539 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
542 cpu_base->expires_next.tv64 = expires_next.tv64;
544 if (cpu_base->expires_next.tv64 != KTIME_MAX)
545 tick_program_event(cpu_base->expires_next, 1);
549 * Shared reprogramming for clock_realtime and clock_monotonic
551 * When a timer is enqueued and expires earlier than the already enqueued
552 * timers, we have to check, whether it expires earlier than the timer for
553 * which the clock event device was armed.
555 * Called with interrupts disabled and base->cpu_base.lock held
557 static int hrtimer_reprogram(struct hrtimer *timer,
558 struct hrtimer_clock_base *base)
560 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
561 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
564 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
567 * When the callback is running, we do not reprogram the clock event
568 * device. The timer callback is either running on a different CPU or
569 * the callback is executed in the hrtimer_interrupt context. The
570 * reprogramming is handled either by the softirq, which called the
571 * callback or at the end of the hrtimer_interrupt.
573 if (hrtimer_callback_running(timer))
577 * CLOCK_REALTIME timer might be requested with an absolute
578 * expiry time which is less than base->offset. Nothing wrong
579 * about that, just avoid to call into the tick code, which
580 * has now objections against negative expiry values.
582 if (expires.tv64 < 0)
585 if (expires.tv64 >= cpu_base->expires_next.tv64)
589 * If a hang was detected in the last timer interrupt then we
590 * do not schedule a timer which is earlier than the expiry
591 * which we enforced in the hang detection. We want the system
594 if (cpu_base->hang_detected)
598 * Clockevents returns -ETIME, when the event was in the past.
600 res = tick_program_event(expires, 0);
601 if (!IS_ERR_VALUE(res))
602 cpu_base->expires_next = expires;
608 * Retrigger next event is called after clock was set
610 * Called with interrupts disabled via on_each_cpu()
612 static void retrigger_next_event(void *arg)
614 struct hrtimer_cpu_base *base;
615 struct timespec realtime_offset, wtm;
618 if (!hrtimer_hres_active())
622 seq = read_seqbegin(&xtime_lock);
623 wtm = __get_wall_to_monotonic();
624 } while (read_seqretry(&xtime_lock, seq));
625 set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
627 base = &__get_cpu_var(hrtimer_bases);
629 /* Adjust CLOCK_REALTIME offset */
630 raw_spin_lock(&base->lock);
631 base->clock_base[CLOCK_REALTIME].offset =
632 timespec_to_ktime(realtime_offset);
634 hrtimer_force_reprogram(base, 0);
635 raw_spin_unlock(&base->lock);
639 * Clock realtime was set
641 * Change the offset of the realtime clock vs. the monotonic
644 * We might have to reprogram the high resolution timer interrupt. On
645 * SMP we call the architecture specific code to retrigger _all_ high
646 * resolution timer interrupts. On UP we just disable interrupts and
647 * call the high resolution interrupt code.
649 void clock_was_set(void)
651 /* Retrigger the CPU local events everywhere */
652 on_each_cpu(retrigger_next_event, NULL, 1);
656 * During resume we might have to reprogram the high resolution timer
657 * interrupt (on the local CPU):
659 void hres_timers_resume(void)
661 WARN_ONCE(!irqs_disabled(),
662 KERN_INFO "hres_timers_resume() called with IRQs enabled!");
664 retrigger_next_event(NULL);
668 * Initialize the high resolution related parts of cpu_base
670 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
672 base->expires_next.tv64 = KTIME_MAX;
673 base->hres_active = 0;
677 * Initialize the high resolution related parts of a hrtimer
679 static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
685 * When High resolution timers are active, try to reprogram. Note, that in case
686 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
687 * check happens. The timer gets enqueued into the rbtree. The reprogramming
688 * and expiry check is done in the hrtimer_interrupt or in the softirq.
690 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
691 struct hrtimer_clock_base *base,
694 if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
696 raw_spin_unlock(&base->cpu_base->lock);
697 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
698 raw_spin_lock(&base->cpu_base->lock);
700 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
709 * Switch to high resolution mode
711 static int hrtimer_switch_to_hres(void)
713 int cpu = smp_processor_id();
714 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
717 if (base->hres_active)
720 local_irq_save(flags);
722 if (tick_init_highres()) {
723 local_irq_restore(flags);
724 printk(KERN_WARNING "Could not switch to high resolution "
725 "mode on CPU %d\n", cpu);
728 base->hres_active = 1;
729 base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES;
730 base->clock_base[CLOCK_MONOTONIC].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) { }
754 static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
756 #endif /* CONFIG_HIGH_RES_TIMERS */
758 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
760 #ifdef CONFIG_TIMER_STATS
761 if (timer->start_site)
763 timer->start_site = __builtin_return_address(0);
764 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
765 timer->start_pid = current->pid;
769 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
771 #ifdef CONFIG_TIMER_STATS
772 timer->start_site = NULL;
776 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
778 #ifdef CONFIG_TIMER_STATS
779 if (likely(!timer_stats_active))
781 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
782 timer->function, timer->start_comm, 0);
787 * Counterpart to lock_hrtimer_base above:
790 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
792 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
796 * hrtimer_forward - forward the timer expiry
797 * @timer: hrtimer to forward
798 * @now: forward past this time
799 * @interval: the interval to forward
801 * Forward the timer expiry so it will expire in the future.
802 * Returns the number of overruns.
804 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
809 delta = ktime_sub(now, hrtimer_get_expires(timer));
814 if (interval.tv64 < timer->base->resolution.tv64)
815 interval.tv64 = timer->base->resolution.tv64;
817 if (unlikely(delta.tv64 >= interval.tv64)) {
818 s64 incr = ktime_to_ns(interval);
820 orun = ktime_divns(delta, incr);
821 hrtimer_add_expires_ns(timer, incr * orun);
822 if (hrtimer_get_expires_tv64(timer) > now.tv64)
825 * This (and the ktime_add() below) is the
826 * correction for exact:
830 hrtimer_add_expires(timer, interval);
834 EXPORT_SYMBOL_GPL(hrtimer_forward);
837 * enqueue_hrtimer - internal function to (re)start a timer
839 * The timer is inserted in expiry order. Insertion into the
840 * red black tree is O(log(n)). Must hold the base lock.
842 * Returns 1 when the new timer is the leftmost timer in the tree.
844 static int enqueue_hrtimer(struct hrtimer *timer,
845 struct hrtimer_clock_base *base)
847 struct rb_node **link = &base->active.rb_node;
848 struct rb_node *parent = NULL;
849 struct hrtimer *entry;
852 debug_activate(timer);
855 * Find the right place in the rbtree:
859 entry = rb_entry(parent, struct hrtimer, node);
861 * We dont care about collisions. Nodes with
862 * the same expiry time stay together.
864 if (hrtimer_get_expires_tv64(timer) <
865 hrtimer_get_expires_tv64(entry)) {
866 link = &(*link)->rb_left;
868 link = &(*link)->rb_right;
874 * Insert the timer to the rbtree and check whether it
875 * replaces the first pending timer
878 base->first = &timer->node;
880 rb_link_node(&timer->node, parent, link);
881 rb_insert_color(&timer->node, &base->active);
883 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
884 * state of a possibly running callback.
886 timer->state |= HRTIMER_STATE_ENQUEUED;
892 * __remove_hrtimer - internal function to remove a timer
894 * Caller must hold the base lock.
896 * High resolution timer mode reprograms the clock event device when the
897 * timer is the one which expires next. The caller can disable this by setting
898 * reprogram to zero. This is useful, when the context does a reprogramming
899 * anyway (e.g. timer interrupt)
901 static void __remove_hrtimer(struct hrtimer *timer,
902 struct hrtimer_clock_base *base,
903 unsigned long newstate, int reprogram)
905 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
909 * Remove the timer from the rbtree and replace the first
910 * entry pointer if necessary.
912 if (base->first == &timer->node) {
913 base->first = rb_next(&timer->node);
914 #ifdef CONFIG_HIGH_RES_TIMERS
915 /* Reprogram the clock event device. if enabled */
916 if (reprogram && hrtimer_hres_active()) {
919 expires = ktime_sub(hrtimer_get_expires(timer),
921 if (base->cpu_base->expires_next.tv64 == expires.tv64)
922 hrtimer_force_reprogram(base->cpu_base, 1);
926 rb_erase(&timer->node, &base->active);
928 timer->state = newstate;
932 * remove hrtimer, called with base lock held
935 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
937 if (hrtimer_is_queued(timer)) {
941 * Remove the timer and force reprogramming when high
942 * resolution mode is active and the timer is on the current
943 * CPU. If we remove a timer on another CPU, reprogramming is
944 * skipped. The interrupt event on this CPU is fired and
945 * reprogramming happens in the interrupt handler. This is a
946 * rare case and less expensive than a smp call.
948 debug_deactivate(timer);
949 timer_stats_hrtimer_clear_start_info(timer);
950 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
951 __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
958 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
959 unsigned long delta_ns, const enum hrtimer_mode mode,
962 struct hrtimer_clock_base *base, *new_base;
966 base = lock_hrtimer_base(timer, &flags);
968 /* Remove an active timer from the queue: */
969 ret = remove_hrtimer(timer, base);
971 /* Switch the timer base, if necessary: */
972 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
974 if (mode & HRTIMER_MODE_REL) {
975 tim = ktime_add_safe(tim, new_base->get_time());
977 * CONFIG_TIME_LOW_RES is a temporary way for architectures
978 * to signal that they simply return xtime in
979 * do_gettimeoffset(). In this case we want to round up by
980 * resolution when starting a relative timer, to avoid short
981 * timeouts. This will go away with the GTOD framework.
983 #ifdef CONFIG_TIME_LOW_RES
984 tim = ktime_add_safe(tim, base->resolution);
988 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
990 timer_stats_hrtimer_set_start_info(timer);
992 leftmost = enqueue_hrtimer(timer, new_base);
995 * Only allow reprogramming if the new base is on this CPU.
996 * (it might still be on another CPU if the timer was pending)
998 * XXX send_remote_softirq() ?
1000 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
1001 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
1003 unlock_hrtimer_base(timer, &flags);
1009 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
1010 * @timer: the timer to be added
1012 * @delta_ns: "slack" range for the timer
1013 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1017 * 1 when the timer was active
1019 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1020 unsigned long delta_ns, const enum hrtimer_mode mode)
1022 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1024 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1027 * hrtimer_start - (re)start an hrtimer on the current CPU
1028 * @timer: the timer to be added
1030 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1034 * 1 when the timer was active
1037 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1039 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1041 EXPORT_SYMBOL_GPL(hrtimer_start);
1045 * hrtimer_try_to_cancel - try to deactivate a timer
1046 * @timer: hrtimer to stop
1049 * 0 when the timer was not active
1050 * 1 when the timer was active
1051 * -1 when the timer is currently excuting the callback function and
1054 int hrtimer_try_to_cancel(struct hrtimer *timer)
1056 struct hrtimer_clock_base *base;
1057 unsigned long flags;
1060 base = lock_hrtimer_base(timer, &flags);
1062 if (!hrtimer_callback_running(timer))
1063 ret = remove_hrtimer(timer, base);
1065 unlock_hrtimer_base(timer, &flags);
1070 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1073 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1074 * @timer: the timer to be cancelled
1077 * 0 when the timer was not active
1078 * 1 when the timer was active
1080 int hrtimer_cancel(struct hrtimer *timer)
1083 int ret = hrtimer_try_to_cancel(timer);
1090 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1093 * hrtimer_get_remaining - get remaining time for the timer
1094 * @timer: the timer to read
1096 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1098 struct hrtimer_clock_base *base;
1099 unsigned long flags;
1102 base = lock_hrtimer_base(timer, &flags);
1103 rem = hrtimer_expires_remaining(timer);
1104 unlock_hrtimer_base(timer, &flags);
1108 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1112 * hrtimer_get_next_event - get the time until next expiry event
1114 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1117 ktime_t hrtimer_get_next_event(void)
1119 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1120 struct hrtimer_clock_base *base = cpu_base->clock_base;
1121 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1122 unsigned long flags;
1125 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1127 if (!hrtimer_hres_active()) {
1128 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1129 struct hrtimer *timer;
1134 timer = rb_entry(base->first, struct hrtimer, node);
1135 delta.tv64 = hrtimer_get_expires_tv64(timer);
1136 delta = ktime_sub(delta, base->get_time());
1137 if (delta.tv64 < mindelta.tv64)
1138 mindelta.tv64 = delta.tv64;
1142 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1144 if (mindelta.tv64 < 0)
1150 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1151 enum hrtimer_mode mode)
1153 struct hrtimer_cpu_base *cpu_base;
1155 memset(timer, 0, sizeof(struct hrtimer));
1157 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1159 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1160 clock_id = CLOCK_MONOTONIC;
1162 timer->base = &cpu_base->clock_base[clock_id];
1163 hrtimer_init_timer_hres(timer);
1165 #ifdef CONFIG_TIMER_STATS
1166 timer->start_site = NULL;
1167 timer->start_pid = -1;
1168 memset(timer->start_comm, 0, TASK_COMM_LEN);
1173 * hrtimer_init - initialize a timer to the given clock
1174 * @timer: the timer to be initialized
1175 * @clock_id: the clock to be used
1176 * @mode: timer mode abs/rel
1178 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1179 enum hrtimer_mode mode)
1181 debug_init(timer, clock_id, mode);
1182 __hrtimer_init(timer, clock_id, mode);
1184 EXPORT_SYMBOL_GPL(hrtimer_init);
1187 * hrtimer_get_res - get the timer resolution for a clock
1188 * @which_clock: which clock to query
1189 * @tp: pointer to timespec variable to store the resolution
1191 * Store the resolution of the clock selected by @which_clock in the
1192 * variable pointed to by @tp.
1194 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1196 struct hrtimer_cpu_base *cpu_base;
1198 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1199 *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
1203 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1205 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1207 struct hrtimer_clock_base *base = timer->base;
1208 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1209 enum hrtimer_restart (*fn)(struct hrtimer *);
1212 WARN_ON(!irqs_disabled());
1214 debug_deactivate(timer);
1215 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1216 timer_stats_account_hrtimer(timer);
1217 fn = timer->function;
1220 * Because we run timers from hardirq context, there is no chance
1221 * they get migrated to another cpu, therefore its safe to unlock
1224 raw_spin_unlock(&cpu_base->lock);
1225 trace_hrtimer_expire_entry(timer, now);
1226 restart = fn(timer);
1227 trace_hrtimer_expire_exit(timer);
1228 raw_spin_lock(&cpu_base->lock);
1231 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1232 * we do not reprogramm the event hardware. Happens either in
1233 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1235 if (restart != HRTIMER_NORESTART) {
1236 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1237 enqueue_hrtimer(timer, base);
1239 timer->state &= ~HRTIMER_STATE_CALLBACK;
1242 #ifdef CONFIG_HIGH_RES_TIMERS
1245 * High resolution timer interrupt
1246 * Called with interrupts disabled
1248 void hrtimer_interrupt(struct clock_event_device *dev)
1250 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1251 struct hrtimer_clock_base *base;
1252 ktime_t expires_next, now, entry_time, delta;
1255 BUG_ON(!cpu_base->hres_active);
1256 cpu_base->nr_events++;
1257 dev->next_event.tv64 = KTIME_MAX;
1259 entry_time = now = ktime_get();
1261 expires_next.tv64 = KTIME_MAX;
1263 raw_spin_lock(&cpu_base->lock);
1265 * We set expires_next to KTIME_MAX here with cpu_base->lock
1266 * held to prevent that a timer is enqueued in our queue via
1267 * the migration code. This does not affect enqueueing of
1268 * timers which run their callback and need to be requeued on
1271 cpu_base->expires_next.tv64 = KTIME_MAX;
1273 base = cpu_base->clock_base;
1275 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1277 struct rb_node *node;
1279 basenow = ktime_add(now, base->offset);
1281 while ((node = base->first)) {
1282 struct hrtimer *timer;
1284 timer = rb_entry(node, struct hrtimer, node);
1287 * The immediate goal for using the softexpires is
1288 * minimizing wakeups, not running timers at the
1289 * earliest interrupt after their soft expiration.
1290 * This allows us to avoid using a Priority Search
1291 * Tree, which can answer a stabbing querry for
1292 * overlapping intervals and instead use the simple
1293 * BST we already have.
1294 * We don't add extra wakeups by delaying timers that
1295 * are right-of a not yet expired timer, because that
1296 * timer will have to trigger a wakeup anyway.
1299 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1302 expires = ktime_sub(hrtimer_get_expires(timer),
1304 if (expires.tv64 < expires_next.tv64)
1305 expires_next = expires;
1309 __run_hrtimer(timer, &basenow);
1315 * Store the new expiry value so the migration code can verify
1318 cpu_base->expires_next = expires_next;
1319 raw_spin_unlock(&cpu_base->lock);
1321 /* Reprogramming necessary ? */
1322 if (expires_next.tv64 == KTIME_MAX ||
1323 !tick_program_event(expires_next, 0)) {
1324 cpu_base->hang_detected = 0;
1329 * The next timer was already expired due to:
1331 * - long lasting callbacks
1332 * - being scheduled away when running in a VM
1334 * We need to prevent that we loop forever in the hrtimer
1335 * interrupt routine. We give it 3 attempts to avoid
1336 * overreacting on some spurious event.
1339 cpu_base->nr_retries++;
1343 * Give the system a chance to do something else than looping
1344 * here. We stored the entry time, so we know exactly how long
1345 * we spent here. We schedule the next event this amount of
1348 cpu_base->nr_hangs++;
1349 cpu_base->hang_detected = 1;
1350 delta = ktime_sub(now, entry_time);
1351 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1352 cpu_base->max_hang_time = delta;
1354 * Limit it to a sensible value as we enforce a longer
1355 * delay. Give the CPU at least 100ms to catch up.
1357 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1358 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1360 expires_next = ktime_add(now, delta);
1361 tick_program_event(expires_next, 1);
1362 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1363 ktime_to_ns(delta));
1367 * local version of hrtimer_peek_ahead_timers() called with interrupts
1370 static void __hrtimer_peek_ahead_timers(void)
1372 struct tick_device *td;
1374 if (!hrtimer_hres_active())
1377 td = &__get_cpu_var(tick_cpu_device);
1378 if (td && td->evtdev)
1379 hrtimer_interrupt(td->evtdev);
1383 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1385 * hrtimer_peek_ahead_timers will peek at the timer queue of
1386 * the current cpu and check if there are any timers for which
1387 * the soft expires time has passed. If any such timers exist,
1388 * they are run immediately and then removed from the timer queue.
1391 void hrtimer_peek_ahead_timers(void)
1393 unsigned long flags;
1395 local_irq_save(flags);
1396 __hrtimer_peek_ahead_timers();
1397 local_irq_restore(flags);
1400 static void run_hrtimer_softirq(struct softirq_action *h)
1402 hrtimer_peek_ahead_timers();
1405 #else /* CONFIG_HIGH_RES_TIMERS */
1407 static inline void __hrtimer_peek_ahead_timers(void) { }
1409 #endif /* !CONFIG_HIGH_RES_TIMERS */
1412 * Called from timer softirq every jiffy, expire hrtimers:
1414 * For HRT its the fall back code to run the softirq in the timer
1415 * softirq context in case the hrtimer initialization failed or has
1416 * not been done yet.
1418 void hrtimer_run_pending(void)
1420 if (hrtimer_hres_active())
1424 * This _is_ ugly: We have to check in the softirq context,
1425 * whether we can switch to highres and / or nohz mode. The
1426 * clocksource switch happens in the timer interrupt with
1427 * xtime_lock held. Notification from there only sets the
1428 * check bit in the tick_oneshot code, otherwise we might
1429 * deadlock vs. xtime_lock.
1431 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1432 hrtimer_switch_to_hres();
1436 * Called from hardirq context every jiffy
1438 void hrtimer_run_queues(void)
1440 struct rb_node *node;
1441 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1442 struct hrtimer_clock_base *base;
1443 int index, gettime = 1;
1445 if (hrtimer_hres_active())
1448 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1449 base = &cpu_base->clock_base[index];
1455 hrtimer_get_softirq_time(cpu_base);
1459 raw_spin_lock(&cpu_base->lock);
1461 while ((node = base->first)) {
1462 struct hrtimer *timer;
1464 timer = rb_entry(node, struct hrtimer, node);
1465 if (base->softirq_time.tv64 <=
1466 hrtimer_get_expires_tv64(timer))
1469 __run_hrtimer(timer, &base->softirq_time);
1471 raw_spin_unlock(&cpu_base->lock);
1476 * Sleep related functions:
1478 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1480 struct hrtimer_sleeper *t =
1481 container_of(timer, struct hrtimer_sleeper, timer);
1482 struct task_struct *task = t->task;
1486 wake_up_process(task);
1488 return HRTIMER_NORESTART;
1491 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1493 sl->timer.function = hrtimer_wakeup;
1496 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1498 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1500 hrtimer_init_sleeper(t, current);
1503 set_current_state(TASK_INTERRUPTIBLE);
1504 hrtimer_start_expires(&t->timer, mode);
1505 if (!hrtimer_active(&t->timer))
1508 if (likely(t->task))
1511 hrtimer_cancel(&t->timer);
1512 mode = HRTIMER_MODE_ABS;
1514 } while (t->task && !signal_pending(current));
1516 __set_current_state(TASK_RUNNING);
1518 return t->task == NULL;
1521 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1523 struct timespec rmt;
1526 rem = hrtimer_expires_remaining(timer);
1529 rmt = ktime_to_timespec(rem);
1531 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1537 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1539 struct hrtimer_sleeper t;
1540 struct timespec __user *rmtp;
1543 hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
1545 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1547 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1550 rmtp = restart->nanosleep.rmtp;
1552 ret = update_rmtp(&t.timer, rmtp);
1557 /* The other values in restart are already filled in */
1558 ret = -ERESTART_RESTARTBLOCK;
1560 destroy_hrtimer_on_stack(&t.timer);
1564 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1565 const enum hrtimer_mode mode, const clockid_t clockid)
1567 struct restart_block *restart;
1568 struct hrtimer_sleeper t;
1570 unsigned long slack;
1572 slack = current->timer_slack_ns;
1573 if (rt_task(current))
1576 hrtimer_init_on_stack(&t.timer, clockid, mode);
1577 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1578 if (do_nanosleep(&t, mode))
1581 /* Absolute timers do not update the rmtp value and restart: */
1582 if (mode == HRTIMER_MODE_ABS) {
1583 ret = -ERESTARTNOHAND;
1588 ret = update_rmtp(&t.timer, rmtp);
1593 restart = ¤t_thread_info()->restart_block;
1594 restart->fn = hrtimer_nanosleep_restart;
1595 restart->nanosleep.index = t.timer.base->index;
1596 restart->nanosleep.rmtp = rmtp;
1597 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1599 ret = -ERESTART_RESTARTBLOCK;
1601 destroy_hrtimer_on_stack(&t.timer);
1605 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1606 struct timespec __user *, rmtp)
1610 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1613 if (!timespec_valid(&tu))
1616 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1620 * Functions related to boot-time initialization:
1622 static void __cpuinit init_hrtimers_cpu(int cpu)
1624 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1627 raw_spin_lock_init(&cpu_base->lock);
1629 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
1630 cpu_base->clock_base[i].cpu_base = cpu_base;
1632 hrtimer_init_hres(cpu_base);
1635 #ifdef CONFIG_HOTPLUG_CPU
1637 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1638 struct hrtimer_clock_base *new_base)
1640 struct hrtimer *timer;
1641 struct rb_node *node;
1643 while ((node = rb_first(&old_base->active))) {
1644 timer = rb_entry(node, struct hrtimer, node);
1645 BUG_ON(hrtimer_callback_running(timer));
1646 debug_deactivate(timer);
1649 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1650 * timer could be seen as !active and just vanish away
1651 * under us on another CPU
1653 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1654 timer->base = new_base;
1656 * Enqueue the timers on the new cpu. This does not
1657 * reprogram the event device in case the timer
1658 * expires before the earliest on this CPU, but we run
1659 * hrtimer_interrupt after we migrated everything to
1660 * sort out already expired timers and reprogram the
1663 enqueue_hrtimer(timer, new_base);
1665 /* Clear the migration state bit */
1666 timer->state &= ~HRTIMER_STATE_MIGRATE;
1670 static void migrate_hrtimers(int scpu)
1672 struct hrtimer_cpu_base *old_base, *new_base;
1675 BUG_ON(cpu_online(scpu));
1676 tick_cancel_sched_timer(scpu);
1678 local_irq_disable();
1679 old_base = &per_cpu(hrtimer_bases, scpu);
1680 new_base = &__get_cpu_var(hrtimer_bases);
1682 * The caller is globally serialized and nobody else
1683 * takes two locks at once, deadlock is not possible.
1685 raw_spin_lock(&new_base->lock);
1686 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1688 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1689 migrate_hrtimer_list(&old_base->clock_base[i],
1690 &new_base->clock_base[i]);
1693 raw_spin_unlock(&old_base->lock);
1694 raw_spin_unlock(&new_base->lock);
1696 /* Check, if we got expired work to do */
1697 __hrtimer_peek_ahead_timers();
1701 #endif /* CONFIG_HOTPLUG_CPU */
1703 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1704 unsigned long action, void *hcpu)
1706 int scpu = (long)hcpu;
1710 case CPU_UP_PREPARE:
1711 case CPU_UP_PREPARE_FROZEN:
1712 init_hrtimers_cpu(scpu);
1715 #ifdef CONFIG_HOTPLUG_CPU
1717 case CPU_DYING_FROZEN:
1718 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1721 case CPU_DEAD_FROZEN:
1723 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1724 migrate_hrtimers(scpu);
1736 static struct notifier_block __cpuinitdata hrtimers_nb = {
1737 .notifier_call = hrtimer_cpu_notify,
1740 void __init hrtimers_init(void)
1742 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1743 (void *)(long)smp_processor_id());
1744 register_cpu_notifier(&hrtimers_nb);
1745 #ifdef CONFIG_HIGH_RES_TIMERS
1746 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1751 * schedule_hrtimeout_range_clock - sleep until timeout
1752 * @expires: timeout value (ktime_t)
1753 * @delta: slack in expires timeout (ktime_t)
1754 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1755 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1758 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1759 const enum hrtimer_mode mode, int clock)
1761 struct hrtimer_sleeper t;
1764 * Optimize when a zero timeout value is given. It does not
1765 * matter whether this is an absolute or a relative time.
1767 if (expires && !expires->tv64) {
1768 __set_current_state(TASK_RUNNING);
1773 * A NULL parameter means "inifinte"
1777 __set_current_state(TASK_RUNNING);
1781 hrtimer_init_on_stack(&t.timer, clock, mode);
1782 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1784 hrtimer_init_sleeper(&t, current);
1786 hrtimer_start_expires(&t.timer, mode);
1787 if (!hrtimer_active(&t.timer))
1793 hrtimer_cancel(&t.timer);
1794 destroy_hrtimer_on_stack(&t.timer);
1796 __set_current_state(TASK_RUNNING);
1798 return !t.task ? 0 : -EINTR;
1802 * schedule_hrtimeout_range - sleep until timeout
1803 * @expires: timeout value (ktime_t)
1804 * @delta: slack in expires timeout (ktime_t)
1805 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1807 * Make the current task sleep until the given expiry time has
1808 * elapsed. The routine will return immediately unless
1809 * the current task state has been set (see set_current_state()).
1811 * The @delta argument gives the kernel the freedom to schedule the
1812 * actual wakeup to a time that is both power and performance friendly.
1813 * The kernel give the normal best effort behavior for "@expires+@delta",
1814 * but may decide to fire the timer earlier, but no earlier than @expires.
1816 * You can set the task state as follows -
1818 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1819 * pass before the routine returns.
1821 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1822 * delivered to the current task.
1824 * The current task state is guaranteed to be TASK_RUNNING when this
1827 * Returns 0 when the timer has expired otherwise -EINTR
1829 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1830 const enum hrtimer_mode mode)
1832 return schedule_hrtimeout_range_clock(expires, delta, mode,
1835 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1838 * schedule_hrtimeout - sleep until timeout
1839 * @expires: timeout value (ktime_t)
1840 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1842 * Make the current task sleep until the given expiry time has
1843 * elapsed. The routine will return immediately unless
1844 * the current task state has been set (see set_current_state()).
1846 * You can set the task state as follows -
1848 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1849 * pass before the routine returns.
1851 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1852 * delivered to the current task.
1854 * The current task state is guaranteed to be TASK_RUNNING when this
1857 * Returns 0 when the timer has expired otherwise -EINTR
1859 int __sched schedule_hrtimeout(ktime_t *expires,
1860 const enum hrtimer_mode mode)
1862 return schedule_hrtimeout_range(expires, 0, mode);
1864 EXPORT_SYMBOL_GPL(schedule_hrtimeout);