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 return get_nohz_timer_target();
154 * With HIGHRES=y we do not migrate the timer when it is expiring
155 * before the next event on the target cpu because we cannot reprogram
156 * the target cpu hardware and we would cause it to fire late.
158 * Called with cpu_base->lock of target cpu held.
161 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
163 #ifdef CONFIG_HIGH_RES_TIMERS
166 if (!new_base->cpu_base->hres_active)
169 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
170 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
177 * Switch the timer base to the current CPU when possible.
179 static inline struct hrtimer_clock_base *
180 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
183 struct hrtimer_clock_base *new_base;
184 struct hrtimer_cpu_base *new_cpu_base;
185 int this_cpu = smp_processor_id();
186 int cpu = hrtimer_get_target(this_cpu, pinned);
189 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
190 new_base = &new_cpu_base->clock_base[base->index];
192 if (base != new_base) {
194 * We are trying to move timer to new_base.
195 * However we can't change timer's base while it is running,
196 * so we keep it on the same CPU. No hassle vs. reprogramming
197 * the event source in the high resolution case. The softirq
198 * code will take care of this when the timer function has
199 * completed. There is no conflict as we hold the lock until
200 * the timer is enqueued.
202 if (unlikely(hrtimer_callback_running(timer)))
205 /* See the comment in lock_timer_base() */
207 raw_spin_unlock(&base->cpu_base->lock);
208 raw_spin_lock(&new_base->cpu_base->lock);
210 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
212 raw_spin_unlock(&new_base->cpu_base->lock);
213 raw_spin_lock(&base->cpu_base->lock);
217 timer->base = new_base;
222 #else /* CONFIG_SMP */
224 static inline struct hrtimer_clock_base *
225 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
227 struct hrtimer_clock_base *base = timer->base;
229 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
234 # define switch_hrtimer_base(t, b, p) (b)
236 #endif /* !CONFIG_SMP */
239 * Functions for the union type storage format of ktime_t which are
240 * too large for inlining:
242 #if BITS_PER_LONG < 64
243 # ifndef CONFIG_KTIME_SCALAR
245 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
247 * @nsec: the scalar nsec value to add
249 * Returns the sum of kt and nsec in ktime_t format
251 ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
255 if (likely(nsec < NSEC_PER_SEC)) {
258 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
260 tmp = ktime_set((long)nsec, rem);
263 return ktime_add(kt, tmp);
266 EXPORT_SYMBOL_GPL(ktime_add_ns);
269 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
271 * @nsec: the scalar nsec value to subtract
273 * Returns the subtraction of @nsec from @kt in ktime_t format
275 ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
279 if (likely(nsec < NSEC_PER_SEC)) {
282 unsigned long rem = do_div(nsec, NSEC_PER_SEC);
284 tmp = ktime_set((long)nsec, rem);
287 return ktime_sub(kt, tmp);
290 EXPORT_SYMBOL_GPL(ktime_sub_ns);
291 # endif /* !CONFIG_KTIME_SCALAR */
294 * Divide a ktime value by a nanosecond value
296 u64 ktime_divns(const ktime_t kt, s64 div)
301 dclc = ktime_to_ns(kt);
302 /* Make sure the divisor is less than 2^32: */
308 do_div(dclc, (unsigned long) div);
312 #endif /* BITS_PER_LONG >= 64 */
315 * Add two ktime values and do a safety check for overflow:
317 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
319 ktime_t res = ktime_add(lhs, rhs);
322 * We use KTIME_SEC_MAX here, the maximum timeout which we can
323 * return to user space in a timespec:
325 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
326 res = ktime_set(KTIME_SEC_MAX, 0);
331 EXPORT_SYMBOL_GPL(ktime_add_safe);
333 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
335 static struct debug_obj_descr hrtimer_debug_descr;
338 * fixup_init is called when:
339 * - an active object is initialized
341 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
343 struct hrtimer *timer = addr;
346 case ODEBUG_STATE_ACTIVE:
347 hrtimer_cancel(timer);
348 debug_object_init(timer, &hrtimer_debug_descr);
356 * fixup_activate is called when:
357 * - an active object is activated
358 * - an unknown object is activated (might be a statically initialized object)
360 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
364 case ODEBUG_STATE_NOTAVAILABLE:
368 case ODEBUG_STATE_ACTIVE:
377 * fixup_free is called when:
378 * - an active object is freed
380 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
382 struct hrtimer *timer = addr;
385 case ODEBUG_STATE_ACTIVE:
386 hrtimer_cancel(timer);
387 debug_object_free(timer, &hrtimer_debug_descr);
394 static struct debug_obj_descr hrtimer_debug_descr = {
396 .fixup_init = hrtimer_fixup_init,
397 .fixup_activate = hrtimer_fixup_activate,
398 .fixup_free = hrtimer_fixup_free,
401 static inline void debug_hrtimer_init(struct hrtimer *timer)
403 debug_object_init(timer, &hrtimer_debug_descr);
406 static inline void debug_hrtimer_activate(struct hrtimer *timer)
408 debug_object_activate(timer, &hrtimer_debug_descr);
411 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
413 debug_object_deactivate(timer, &hrtimer_debug_descr);
416 static inline void debug_hrtimer_free(struct hrtimer *timer)
418 debug_object_free(timer, &hrtimer_debug_descr);
421 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
422 enum hrtimer_mode mode);
424 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
425 enum hrtimer_mode mode)
427 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
428 __hrtimer_init(timer, clock_id, mode);
430 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
432 void destroy_hrtimer_on_stack(struct hrtimer *timer)
434 debug_object_free(timer, &hrtimer_debug_descr);
438 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
439 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
440 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
444 debug_init(struct hrtimer *timer, clockid_t clockid,
445 enum hrtimer_mode mode)
447 debug_hrtimer_init(timer);
448 trace_hrtimer_init(timer, clockid, mode);
451 static inline void debug_activate(struct hrtimer *timer)
453 debug_hrtimer_activate(timer);
454 trace_hrtimer_start(timer);
457 static inline void debug_deactivate(struct hrtimer *timer)
459 debug_hrtimer_deactivate(timer);
460 trace_hrtimer_cancel(timer);
463 /* High resolution timer related functions */
464 #ifdef CONFIG_HIGH_RES_TIMERS
467 * High resolution timer enabled ?
469 static int hrtimer_hres_enabled __read_mostly = 1;
472 * Enable / Disable high resolution mode
474 static int __init setup_hrtimer_hres(char *str)
476 if (!strcmp(str, "off"))
477 hrtimer_hres_enabled = 0;
478 else if (!strcmp(str, "on"))
479 hrtimer_hres_enabled = 1;
485 __setup("highres=", setup_hrtimer_hres);
488 * hrtimer_high_res_enabled - query, if the highres mode is enabled
490 static inline int hrtimer_is_hres_enabled(void)
492 return hrtimer_hres_enabled;
496 * Is the high resolution mode active ?
498 static inline int hrtimer_hres_active(void)
500 return __get_cpu_var(hrtimer_bases).hres_active;
504 * Reprogram the event source with checking both queues for the
506 * Called with interrupts disabled and base->lock held
509 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
512 struct hrtimer_clock_base *base = cpu_base->clock_base;
513 ktime_t expires, expires_next;
515 expires_next.tv64 = KTIME_MAX;
517 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
518 struct hrtimer *timer;
519 struct timerqueue_node *next;
521 next = timerqueue_getnext(&base->active);
524 timer = container_of(next, struct hrtimer, node);
526 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
528 * clock_was_set() has changed base->offset so the
529 * result might be negative. Fix it up to prevent a
530 * false positive in clockevents_program_event()
532 if (expires.tv64 < 0)
534 if (expires.tv64 < expires_next.tv64)
535 expires_next = expires;
538 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
541 cpu_base->expires_next.tv64 = expires_next.tv64;
543 if (cpu_base->expires_next.tv64 != KTIME_MAX)
544 tick_program_event(cpu_base->expires_next, 1);
548 * Shared reprogramming for clock_realtime and clock_monotonic
550 * When a timer is enqueued and expires earlier than the already enqueued
551 * timers, we have to check, whether it expires earlier than the timer for
552 * which the clock event device was armed.
554 * Called with interrupts disabled and base->cpu_base.lock held
556 static int hrtimer_reprogram(struct hrtimer *timer,
557 struct hrtimer_clock_base *base)
559 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
560 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
563 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
566 * When the callback is running, we do not reprogram the clock event
567 * device. The timer callback is either running on a different CPU or
568 * the callback is executed in the hrtimer_interrupt context. The
569 * reprogramming is handled either by the softirq, which called the
570 * callback or at the end of the hrtimer_interrupt.
572 if (hrtimer_callback_running(timer))
576 * CLOCK_REALTIME timer might be requested with an absolute
577 * expiry time which is less than base->offset. Nothing wrong
578 * about that, just avoid to call into the tick code, which
579 * has now objections against negative expiry values.
581 if (expires.tv64 < 0)
584 if (expires.tv64 >= cpu_base->expires_next.tv64)
588 * If a hang was detected in the last timer interrupt then we
589 * do not schedule a timer which is earlier than the expiry
590 * which we enforced in the hang detection. We want the system
593 if (cpu_base->hang_detected)
597 * Clockevents returns -ETIME, when the event was in the past.
599 res = tick_program_event(expires, 0);
600 if (!IS_ERR_VALUE(res))
601 cpu_base->expires_next = expires;
607 * Retrigger next event is called after clock was set
609 * Called with interrupts disabled via on_each_cpu()
611 static void retrigger_next_event(void *arg)
613 struct hrtimer_cpu_base *base;
614 struct timespec realtime_offset, wtm;
617 if (!hrtimer_hres_active())
621 seq = read_seqbegin(&xtime_lock);
622 wtm = __get_wall_to_monotonic();
623 } while (read_seqretry(&xtime_lock, seq));
624 set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
626 base = &__get_cpu_var(hrtimer_bases);
628 /* Adjust CLOCK_REALTIME offset */
629 raw_spin_lock(&base->lock);
630 base->clock_base[CLOCK_REALTIME].offset =
631 timespec_to_ktime(realtime_offset);
633 hrtimer_force_reprogram(base, 0);
634 raw_spin_unlock(&base->lock);
638 * Clock realtime was set
640 * Change the offset of the realtime clock vs. the monotonic
643 * We might have to reprogram the high resolution timer interrupt. On
644 * SMP we call the architecture specific code to retrigger _all_ high
645 * resolution timer interrupts. On UP we just disable interrupts and
646 * call the high resolution interrupt code.
648 void clock_was_set(void)
650 /* Retrigger the CPU local events everywhere */
651 on_each_cpu(retrigger_next_event, NULL, 1);
655 * During resume we might have to reprogram the high resolution timer
656 * interrupt (on the local CPU):
658 void hres_timers_resume(void)
660 WARN_ONCE(!irqs_disabled(),
661 KERN_INFO "hres_timers_resume() called with IRQs enabled!");
663 retrigger_next_event(NULL);
667 * Initialize the high resolution related parts of cpu_base
669 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
671 base->expires_next.tv64 = KTIME_MAX;
672 base->hres_active = 0;
676 * Initialize the high resolution related parts of a hrtimer
678 static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
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[CLOCK_REALTIME].resolution = KTIME_HIGH_RES;
729 base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES;
731 tick_setup_sched_timer();
733 /* "Retrigger" the interrupt to get things going */
734 retrigger_next_event(NULL);
735 local_irq_restore(flags);
741 static inline int hrtimer_hres_active(void) { return 0; }
742 static inline int hrtimer_is_hres_enabled(void) { return 0; }
743 static inline int hrtimer_switch_to_hres(void) { return 0; }
745 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
746 static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
747 struct hrtimer_clock_base *base,
752 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
753 static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
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)) {
904 * Remove the timer and force reprogramming when high
905 * resolution mode is active and the timer is on the current
906 * CPU. If we remove a timer on another CPU, reprogramming is
907 * skipped. The interrupt event on this CPU is fired and
908 * reprogramming happens in the interrupt handler. This is a
909 * rare case and less expensive than a smp call.
911 debug_deactivate(timer);
912 timer_stats_hrtimer_clear_start_info(timer);
913 reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
914 __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
921 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
922 unsigned long delta_ns, const enum hrtimer_mode mode,
925 struct hrtimer_clock_base *base, *new_base;
929 base = lock_hrtimer_base(timer, &flags);
931 /* Remove an active timer from the queue: */
932 ret = remove_hrtimer(timer, base);
934 /* Switch the timer base, if necessary: */
935 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
937 if (mode & HRTIMER_MODE_REL) {
938 tim = ktime_add_safe(tim, new_base->get_time());
940 * CONFIG_TIME_LOW_RES is a temporary way for architectures
941 * to signal that they simply return xtime in
942 * do_gettimeoffset(). In this case we want to round up by
943 * resolution when starting a relative timer, to avoid short
944 * timeouts. This will go away with the GTOD framework.
946 #ifdef CONFIG_TIME_LOW_RES
947 tim = ktime_add_safe(tim, base->resolution);
951 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
953 timer_stats_hrtimer_set_start_info(timer);
955 leftmost = enqueue_hrtimer(timer, new_base);
958 * Only allow reprogramming if the new base is on this CPU.
959 * (it might still be on another CPU if the timer was pending)
961 * XXX send_remote_softirq() ?
963 if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
964 hrtimer_enqueue_reprogram(timer, new_base, wakeup);
966 unlock_hrtimer_base(timer, &flags);
972 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
973 * @timer: the timer to be added
975 * @delta_ns: "slack" range for the timer
976 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
980 * 1 when the timer was active
982 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
983 unsigned long delta_ns, const enum hrtimer_mode mode)
985 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
987 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
990 * hrtimer_start - (re)start an hrtimer on the current CPU
991 * @timer: the timer to be added
993 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
997 * 1 when the timer was active
1000 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1002 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1004 EXPORT_SYMBOL_GPL(hrtimer_start);
1008 * hrtimer_try_to_cancel - try to deactivate a timer
1009 * @timer: hrtimer to stop
1012 * 0 when the timer was not active
1013 * 1 when the timer was active
1014 * -1 when the timer is currently excuting the callback function and
1017 int hrtimer_try_to_cancel(struct hrtimer *timer)
1019 struct hrtimer_clock_base *base;
1020 unsigned long flags;
1023 base = lock_hrtimer_base(timer, &flags);
1025 if (!hrtimer_callback_running(timer))
1026 ret = remove_hrtimer(timer, base);
1028 unlock_hrtimer_base(timer, &flags);
1033 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1036 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1037 * @timer: the timer to be cancelled
1040 * 0 when the timer was not active
1041 * 1 when the timer was active
1043 int hrtimer_cancel(struct hrtimer *timer)
1046 int ret = hrtimer_try_to_cancel(timer);
1053 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1056 * hrtimer_get_remaining - get remaining time for the timer
1057 * @timer: the timer to read
1059 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1061 struct hrtimer_clock_base *base;
1062 unsigned long flags;
1065 base = lock_hrtimer_base(timer, &flags);
1066 rem = hrtimer_expires_remaining(timer);
1067 unlock_hrtimer_base(timer, &flags);
1071 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1075 * hrtimer_get_next_event - get the time until next expiry event
1077 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1080 ktime_t hrtimer_get_next_event(void)
1082 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1083 struct hrtimer_clock_base *base = cpu_base->clock_base;
1084 ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1085 unsigned long flags;
1088 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1090 if (!hrtimer_hres_active()) {
1091 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1092 struct hrtimer *timer;
1093 struct timerqueue_node *next;
1095 next = timerqueue_getnext(&base->active);
1099 timer = container_of(next, struct hrtimer, node);
1100 delta.tv64 = hrtimer_get_expires_tv64(timer);
1101 delta = ktime_sub(delta, base->get_time());
1102 if (delta.tv64 < mindelta.tv64)
1103 mindelta.tv64 = delta.tv64;
1107 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1109 if (mindelta.tv64 < 0)
1115 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1116 enum hrtimer_mode mode)
1118 struct hrtimer_cpu_base *cpu_base;
1120 memset(timer, 0, sizeof(struct hrtimer));
1122 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1124 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1125 clock_id = CLOCK_MONOTONIC;
1127 timer->base = &cpu_base->clock_base[clock_id];
1128 hrtimer_init_timer_hres(timer);
1129 timerqueue_init(&timer->node);
1131 #ifdef CONFIG_TIMER_STATS
1132 timer->start_site = NULL;
1133 timer->start_pid = -1;
1134 memset(timer->start_comm, 0, TASK_COMM_LEN);
1139 * hrtimer_init - initialize a timer to the given clock
1140 * @timer: the timer to be initialized
1141 * @clock_id: the clock to be used
1142 * @mode: timer mode abs/rel
1144 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1145 enum hrtimer_mode mode)
1147 debug_init(timer, clock_id, mode);
1148 __hrtimer_init(timer, clock_id, mode);
1150 EXPORT_SYMBOL_GPL(hrtimer_init);
1153 * hrtimer_get_res - get the timer resolution for a clock
1154 * @which_clock: which clock to query
1155 * @tp: pointer to timespec variable to store the resolution
1157 * Store the resolution of the clock selected by @which_clock in the
1158 * variable pointed to by @tp.
1160 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1162 struct hrtimer_cpu_base *cpu_base;
1164 cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1165 *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
1169 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1171 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1173 struct hrtimer_clock_base *base = timer->base;
1174 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1175 enum hrtimer_restart (*fn)(struct hrtimer *);
1178 WARN_ON(!irqs_disabled());
1180 debug_deactivate(timer);
1181 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1182 timer_stats_account_hrtimer(timer);
1183 fn = timer->function;
1186 * Because we run timers from hardirq context, there is no chance
1187 * they get migrated to another cpu, therefore its safe to unlock
1190 raw_spin_unlock(&cpu_base->lock);
1191 trace_hrtimer_expire_entry(timer, now);
1192 restart = fn(timer);
1193 trace_hrtimer_expire_exit(timer);
1194 raw_spin_lock(&cpu_base->lock);
1197 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1198 * we do not reprogramm the event hardware. Happens either in
1199 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1201 if (restart != HRTIMER_NORESTART) {
1202 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1203 enqueue_hrtimer(timer, base);
1205 timer->state &= ~HRTIMER_STATE_CALLBACK;
1208 #ifdef CONFIG_HIGH_RES_TIMERS
1211 * High resolution timer interrupt
1212 * Called with interrupts disabled
1214 void hrtimer_interrupt(struct clock_event_device *dev)
1216 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1217 struct hrtimer_clock_base *base;
1218 ktime_t expires_next, now, entry_time, delta;
1221 BUG_ON(!cpu_base->hres_active);
1222 cpu_base->nr_events++;
1223 dev->next_event.tv64 = KTIME_MAX;
1225 entry_time = now = ktime_get();
1227 expires_next.tv64 = KTIME_MAX;
1229 raw_spin_lock(&cpu_base->lock);
1231 * We set expires_next to KTIME_MAX here with cpu_base->lock
1232 * held to prevent that a timer is enqueued in our queue via
1233 * the migration code. This does not affect enqueueing of
1234 * timers which run their callback and need to be requeued on
1237 cpu_base->expires_next.tv64 = KTIME_MAX;
1239 base = cpu_base->clock_base;
1241 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1243 struct timerqueue_node *node;
1245 basenow = ktime_add(now, base->offset);
1247 while ((node = timerqueue_getnext(&base->active))) {
1248 struct hrtimer *timer;
1250 timer = container_of(node, struct hrtimer, node);
1253 * The immediate goal for using the softexpires is
1254 * minimizing wakeups, not running timers at the
1255 * earliest interrupt after their soft expiration.
1256 * This allows us to avoid using a Priority Search
1257 * Tree, which can answer a stabbing querry for
1258 * overlapping intervals and instead use the simple
1259 * BST we already have.
1260 * We don't add extra wakeups by delaying timers that
1261 * are right-of a not yet expired timer, because that
1262 * timer will have to trigger a wakeup anyway.
1265 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1268 expires = ktime_sub(hrtimer_get_expires(timer),
1270 if (expires.tv64 < expires_next.tv64)
1271 expires_next = expires;
1275 __run_hrtimer(timer, &basenow);
1281 * Store the new expiry value so the migration code can verify
1284 cpu_base->expires_next = expires_next;
1285 raw_spin_unlock(&cpu_base->lock);
1287 /* Reprogramming necessary ? */
1288 if (expires_next.tv64 == KTIME_MAX ||
1289 !tick_program_event(expires_next, 0)) {
1290 cpu_base->hang_detected = 0;
1295 * The next timer was already expired due to:
1297 * - long lasting callbacks
1298 * - being scheduled away when running in a VM
1300 * We need to prevent that we loop forever in the hrtimer
1301 * interrupt routine. We give it 3 attempts to avoid
1302 * overreacting on some spurious event.
1305 cpu_base->nr_retries++;
1309 * Give the system a chance to do something else than looping
1310 * here. We stored the entry time, so we know exactly how long
1311 * we spent here. We schedule the next event this amount of
1314 cpu_base->nr_hangs++;
1315 cpu_base->hang_detected = 1;
1316 delta = ktime_sub(now, entry_time);
1317 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1318 cpu_base->max_hang_time = delta;
1320 * Limit it to a sensible value as we enforce a longer
1321 * delay. Give the CPU at least 100ms to catch up.
1323 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1324 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1326 expires_next = ktime_add(now, delta);
1327 tick_program_event(expires_next, 1);
1328 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1329 ktime_to_ns(delta));
1333 * local version of hrtimer_peek_ahead_timers() called with interrupts
1336 static void __hrtimer_peek_ahead_timers(void)
1338 struct tick_device *td;
1340 if (!hrtimer_hres_active())
1343 td = &__get_cpu_var(tick_cpu_device);
1344 if (td && td->evtdev)
1345 hrtimer_interrupt(td->evtdev);
1349 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1351 * hrtimer_peek_ahead_timers will peek at the timer queue of
1352 * the current cpu and check if there are any timers for which
1353 * the soft expires time has passed. If any such timers exist,
1354 * they are run immediately and then removed from the timer queue.
1357 void hrtimer_peek_ahead_timers(void)
1359 unsigned long flags;
1361 local_irq_save(flags);
1362 __hrtimer_peek_ahead_timers();
1363 local_irq_restore(flags);
1366 static void run_hrtimer_softirq(struct softirq_action *h)
1368 hrtimer_peek_ahead_timers();
1371 #else /* CONFIG_HIGH_RES_TIMERS */
1373 static inline void __hrtimer_peek_ahead_timers(void) { }
1375 #endif /* !CONFIG_HIGH_RES_TIMERS */
1378 * Called from timer softirq every jiffy, expire hrtimers:
1380 * For HRT its the fall back code to run the softirq in the timer
1381 * softirq context in case the hrtimer initialization failed or has
1382 * not been done yet.
1384 void hrtimer_run_pending(void)
1386 if (hrtimer_hres_active())
1390 * This _is_ ugly: We have to check in the softirq context,
1391 * whether we can switch to highres and / or nohz mode. The
1392 * clocksource switch happens in the timer interrupt with
1393 * xtime_lock held. Notification from there only sets the
1394 * check bit in the tick_oneshot code, otherwise we might
1395 * deadlock vs. xtime_lock.
1397 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1398 hrtimer_switch_to_hres();
1402 * Called from hardirq context every jiffy
1404 void hrtimer_run_queues(void)
1406 struct timerqueue_node *node;
1407 struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1408 struct hrtimer_clock_base *base;
1409 int index, gettime = 1;
1411 if (hrtimer_hres_active())
1414 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1415 base = &cpu_base->clock_base[index];
1416 if (!timerqueue_getnext(&base->active))
1420 hrtimer_get_softirq_time(cpu_base);
1424 raw_spin_lock(&cpu_base->lock);
1426 while ((node = timerqueue_getnext(&base->active))) {
1427 struct hrtimer *timer;
1429 timer = container_of(node, struct hrtimer, node);
1430 if (base->softirq_time.tv64 <=
1431 hrtimer_get_expires_tv64(timer))
1434 __run_hrtimer(timer, &base->softirq_time);
1436 raw_spin_unlock(&cpu_base->lock);
1441 * Sleep related functions:
1443 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1445 struct hrtimer_sleeper *t =
1446 container_of(timer, struct hrtimer_sleeper, timer);
1447 struct task_struct *task = t->task;
1451 wake_up_process(task);
1453 return HRTIMER_NORESTART;
1456 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1458 sl->timer.function = hrtimer_wakeup;
1461 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1463 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1465 hrtimer_init_sleeper(t, current);
1468 set_current_state(TASK_INTERRUPTIBLE);
1469 hrtimer_start_expires(&t->timer, mode);
1470 if (!hrtimer_active(&t->timer))
1473 if (likely(t->task))
1476 hrtimer_cancel(&t->timer);
1477 mode = HRTIMER_MODE_ABS;
1479 } while (t->task && !signal_pending(current));
1481 __set_current_state(TASK_RUNNING);
1483 return t->task == NULL;
1486 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1488 struct timespec rmt;
1491 rem = hrtimer_expires_remaining(timer);
1494 rmt = ktime_to_timespec(rem);
1496 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1502 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1504 struct hrtimer_sleeper t;
1505 struct timespec __user *rmtp;
1508 hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
1510 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1512 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1515 rmtp = restart->nanosleep.rmtp;
1517 ret = update_rmtp(&t.timer, rmtp);
1522 /* The other values in restart are already filled in */
1523 ret = -ERESTART_RESTARTBLOCK;
1525 destroy_hrtimer_on_stack(&t.timer);
1529 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1530 const enum hrtimer_mode mode, const clockid_t clockid)
1532 struct restart_block *restart;
1533 struct hrtimer_sleeper t;
1535 unsigned long slack;
1537 slack = current->timer_slack_ns;
1538 if (rt_task(current))
1541 hrtimer_init_on_stack(&t.timer, clockid, mode);
1542 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1543 if (do_nanosleep(&t, mode))
1546 /* Absolute timers do not update the rmtp value and restart: */
1547 if (mode == HRTIMER_MODE_ABS) {
1548 ret = -ERESTARTNOHAND;
1553 ret = update_rmtp(&t.timer, rmtp);
1558 restart = ¤t_thread_info()->restart_block;
1559 restart->fn = hrtimer_nanosleep_restart;
1560 restart->nanosleep.index = t.timer.base->index;
1561 restart->nanosleep.rmtp = rmtp;
1562 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1564 ret = -ERESTART_RESTARTBLOCK;
1566 destroy_hrtimer_on_stack(&t.timer);
1570 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1571 struct timespec __user *, rmtp)
1575 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1578 if (!timespec_valid(&tu))
1581 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1585 * Functions related to boot-time initialization:
1587 static void __cpuinit init_hrtimers_cpu(int cpu)
1589 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1592 raw_spin_lock_init(&cpu_base->lock);
1594 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1595 cpu_base->clock_base[i].cpu_base = cpu_base;
1596 timerqueue_init_head(&cpu_base->clock_base[i].active);
1599 hrtimer_init_hres(cpu_base);
1602 #ifdef CONFIG_HOTPLUG_CPU
1604 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1605 struct hrtimer_clock_base *new_base)
1607 struct hrtimer *timer;
1608 struct timerqueue_node *node;
1610 while ((node = timerqueue_getnext(&old_base->active))) {
1611 timer = container_of(node, struct hrtimer, node);
1612 BUG_ON(hrtimer_callback_running(timer));
1613 debug_deactivate(timer);
1616 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1617 * timer could be seen as !active and just vanish away
1618 * under us on another CPU
1620 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1621 timer->base = new_base;
1623 * Enqueue the timers on the new cpu. This does not
1624 * reprogram the event device in case the timer
1625 * expires before the earliest on this CPU, but we run
1626 * hrtimer_interrupt after we migrated everything to
1627 * sort out already expired timers and reprogram the
1630 enqueue_hrtimer(timer, new_base);
1632 /* Clear the migration state bit */
1633 timer->state &= ~HRTIMER_STATE_MIGRATE;
1637 static void migrate_hrtimers(int scpu)
1639 struct hrtimer_cpu_base *old_base, *new_base;
1642 BUG_ON(cpu_online(scpu));
1643 tick_cancel_sched_timer(scpu);
1645 local_irq_disable();
1646 old_base = &per_cpu(hrtimer_bases, scpu);
1647 new_base = &__get_cpu_var(hrtimer_bases);
1649 * The caller is globally serialized and nobody else
1650 * takes two locks at once, deadlock is not possible.
1652 raw_spin_lock(&new_base->lock);
1653 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1655 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1656 migrate_hrtimer_list(&old_base->clock_base[i],
1657 &new_base->clock_base[i]);
1660 raw_spin_unlock(&old_base->lock);
1661 raw_spin_unlock(&new_base->lock);
1663 /* Check, if we got expired work to do */
1664 __hrtimer_peek_ahead_timers();
1668 #endif /* CONFIG_HOTPLUG_CPU */
1670 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1671 unsigned long action, void *hcpu)
1673 int scpu = (long)hcpu;
1677 case CPU_UP_PREPARE:
1678 case CPU_UP_PREPARE_FROZEN:
1679 init_hrtimers_cpu(scpu);
1682 #ifdef CONFIG_HOTPLUG_CPU
1684 case CPU_DYING_FROZEN:
1685 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1688 case CPU_DEAD_FROZEN:
1690 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1691 migrate_hrtimers(scpu);
1703 static struct notifier_block __cpuinitdata hrtimers_nb = {
1704 .notifier_call = hrtimer_cpu_notify,
1707 void __init hrtimers_init(void)
1709 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1710 (void *)(long)smp_processor_id());
1711 register_cpu_notifier(&hrtimers_nb);
1712 #ifdef CONFIG_HIGH_RES_TIMERS
1713 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1718 * schedule_hrtimeout_range_clock - sleep until timeout
1719 * @expires: timeout value (ktime_t)
1720 * @delta: slack in expires timeout (ktime_t)
1721 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1722 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1725 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1726 const enum hrtimer_mode mode, int clock)
1728 struct hrtimer_sleeper t;
1731 * Optimize when a zero timeout value is given. It does not
1732 * matter whether this is an absolute or a relative time.
1734 if (expires && !expires->tv64) {
1735 __set_current_state(TASK_RUNNING);
1740 * A NULL parameter means "inifinte"
1744 __set_current_state(TASK_RUNNING);
1748 hrtimer_init_on_stack(&t.timer, clock, mode);
1749 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1751 hrtimer_init_sleeper(&t, current);
1753 hrtimer_start_expires(&t.timer, mode);
1754 if (!hrtimer_active(&t.timer))
1760 hrtimer_cancel(&t.timer);
1761 destroy_hrtimer_on_stack(&t.timer);
1763 __set_current_state(TASK_RUNNING);
1765 return !t.task ? 0 : -EINTR;
1769 * schedule_hrtimeout_range - sleep until timeout
1770 * @expires: timeout value (ktime_t)
1771 * @delta: slack in expires timeout (ktime_t)
1772 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1774 * Make the current task sleep until the given expiry time has
1775 * elapsed. The routine will return immediately unless
1776 * the current task state has been set (see set_current_state()).
1778 * The @delta argument gives the kernel the freedom to schedule the
1779 * actual wakeup to a time that is both power and performance friendly.
1780 * The kernel give the normal best effort behavior for "@expires+@delta",
1781 * but may decide to fire the timer earlier, but no earlier than @expires.
1783 * You can set the task state as follows -
1785 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1786 * pass before the routine returns.
1788 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1789 * delivered to the current task.
1791 * The current task state is guaranteed to be TASK_RUNNING when this
1794 * Returns 0 when the timer has expired otherwise -EINTR
1796 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1797 const enum hrtimer_mode mode)
1799 return schedule_hrtimeout_range_clock(expires, delta, mode,
1802 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1805 * schedule_hrtimeout - sleep until timeout
1806 * @expires: timeout value (ktime_t)
1807 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1809 * Make the current task sleep until the given expiry time has
1810 * elapsed. The routine will return immediately unless
1811 * the current task state has been set (see set_current_state()).
1813 * You can set the task state as follows -
1815 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1816 * pass before the routine returns.
1818 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1819 * delivered to the current task.
1821 * The current task state is guaranteed to be TASK_RUNNING when this
1824 * Returns 0 when the timer has expired otherwise -EINTR
1826 int __sched schedule_hrtimeout(ktime_t *expires,
1827 const enum hrtimer_mode mode)
1829 return schedule_hrtimeout_range(expires, 0, mode);
1831 EXPORT_SYMBOL_GPL(schedule_hrtimeout);