2 * linux/kernel/hrtimer.c
4 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
6 * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
8 * High-resolution kernel timers
10 * In contrast to the low-resolution timeout API implemented in
11 * kernel/timer.c, hrtimers provide finer resolution and accuracy
12 * depending on system configuration and capabilities.
14 * These timers are currently used for:
18 * - precise in-kernel timing
20 * Started by: Thomas Gleixner and Ingo Molnar
23 * based on kernel/timer.c
25 * Help, testing, suggestions, bugfixes, improvements were
28 * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
31 * For licencing details see kernel-base/COPYING
34 #include <linux/cpu.h>
35 #include <linux/export.h>
36 #include <linux/percpu.h>
37 #include <linux/hrtimer.h>
38 #include <linux/notifier.h>
39 #include <linux/syscalls.h>
40 #include <linux/kallsyms.h>
41 #include <linux/interrupt.h>
42 #include <linux/tick.h>
43 #include <linux/seq_file.h>
44 #include <linux/err.h>
45 #include <linux/debugobjects.h>
46 #include <linux/sched.h>
47 #include <linux/sched/sysctl.h>
48 #include <linux/sched/rt.h>
49 #include <linux/sched/deadline.h>
50 #include <linux/timer.h>
51 #include <linux/freezer.h>
53 #include <asm/uaccess.h>
55 #include <trace/events/timer.h>
57 #include "tick-internal.h"
62 * There are more clockids then hrtimer bases. Thus, we index
63 * into the timer bases by the hrtimer_base_type enum. When trying
64 * to reach a base using a clockid, hrtimer_clockid_to_base()
65 * is used to convert from clockid to the proper hrtimer_base_type.
67 DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
69 .lock = __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases.lock),
73 .index = HRTIMER_BASE_MONOTONIC,
74 .clockid = CLOCK_MONOTONIC,
75 .get_time = &ktime_get,
78 .index = HRTIMER_BASE_REALTIME,
79 .clockid = CLOCK_REALTIME,
80 .get_time = &ktime_get_real,
83 .index = HRTIMER_BASE_BOOTTIME,
84 .clockid = CLOCK_BOOTTIME,
85 .get_time = &ktime_get_boottime,
88 .index = HRTIMER_BASE_TAI,
90 .get_time = &ktime_get_clocktai,
95 static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
96 [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
97 [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
98 [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
99 [CLOCK_TAI] = HRTIMER_BASE_TAI,
102 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
104 return hrtimer_clock_to_base_table[clock_id];
108 * Functions and macros which are different for UP/SMP systems are kept in a
114 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
115 * means that all timers which are tied to this base via timer->base are
116 * locked, and the base itself is locked too.
118 * So __run_timers/migrate_timers can safely modify all timers which could
119 * be found on the lists/queues.
121 * When the timer's base is locked, and the timer removed from list, it is
122 * possible to set timer->base = NULL and drop the lock: the timer remains
126 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
127 unsigned long *flags)
129 struct hrtimer_clock_base *base;
133 if (likely(base != NULL)) {
134 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
135 if (likely(base == timer->base))
137 /* The timer has migrated to another CPU: */
138 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
145 * With HIGHRES=y we do not migrate the timer when it is expiring
146 * before the next event on the target cpu because we cannot reprogram
147 * the target cpu hardware and we would cause it to fire late.
149 * Called with cpu_base->lock of target cpu held.
152 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
154 #ifdef CONFIG_HIGH_RES_TIMERS
157 if (!new_base->cpu_base->hres_active)
160 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
161 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
168 * Switch the timer base to the current CPU when possible.
170 static inline struct hrtimer_clock_base *
171 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
174 struct hrtimer_clock_base *new_base;
175 struct hrtimer_cpu_base *new_cpu_base;
176 int this_cpu = smp_processor_id();
177 int cpu = get_nohz_timer_target(pinned);
178 int basenum = base->index;
181 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
182 new_base = &new_cpu_base->clock_base[basenum];
184 if (base != new_base) {
186 * We are trying to move timer to new_base.
187 * However we can't change timer's base while it is running,
188 * so we keep it on the same CPU. No hassle vs. reprogramming
189 * the event source in the high resolution case. The softirq
190 * code will take care of this when the timer function has
191 * completed. There is no conflict as we hold the lock until
192 * the timer is enqueued.
194 if (unlikely(hrtimer_callback_running(timer)))
197 /* See the comment in lock_timer_base() */
199 raw_spin_unlock(&base->cpu_base->lock);
200 raw_spin_lock(&new_base->cpu_base->lock);
202 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
204 raw_spin_unlock(&new_base->cpu_base->lock);
205 raw_spin_lock(&base->cpu_base->lock);
209 timer->base = new_base;
211 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
219 #else /* CONFIG_SMP */
221 static inline struct hrtimer_clock_base *
222 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
224 struct hrtimer_clock_base *base = timer->base;
226 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
231 # define switch_hrtimer_base(t, b, p) (b)
233 #endif /* !CONFIG_SMP */
236 * Functions for the union type storage format of ktime_t which are
237 * too large for inlining:
239 #if BITS_PER_LONG < 64
241 * Divide a ktime value by a nanosecond value
243 u64 __ktime_divns(const ktime_t kt, s64 div)
248 dclc = ktime_to_ns(kt);
249 /* Make sure the divisor is less than 2^32: */
255 do_div(dclc, (unsigned long) div);
259 EXPORT_SYMBOL_GPL(__ktime_divns);
260 #endif /* BITS_PER_LONG >= 64 */
263 * Add two ktime values and do a safety check for overflow:
265 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
267 ktime_t res = ktime_add(lhs, rhs);
270 * We use KTIME_SEC_MAX here, the maximum timeout which we can
271 * return to user space in a timespec:
273 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
274 res = ktime_set(KTIME_SEC_MAX, 0);
279 EXPORT_SYMBOL_GPL(ktime_add_safe);
281 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
283 static struct debug_obj_descr hrtimer_debug_descr;
285 static void *hrtimer_debug_hint(void *addr)
287 return ((struct hrtimer *) addr)->function;
291 * fixup_init is called when:
292 * - an active object is initialized
294 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
296 struct hrtimer *timer = addr;
299 case ODEBUG_STATE_ACTIVE:
300 hrtimer_cancel(timer);
301 debug_object_init(timer, &hrtimer_debug_descr);
309 * fixup_activate is called when:
310 * - an active object is activated
311 * - an unknown object is activated (might be a statically initialized object)
313 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
317 case ODEBUG_STATE_NOTAVAILABLE:
321 case ODEBUG_STATE_ACTIVE:
330 * fixup_free is called when:
331 * - an active object is freed
333 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
335 struct hrtimer *timer = addr;
338 case ODEBUG_STATE_ACTIVE:
339 hrtimer_cancel(timer);
340 debug_object_free(timer, &hrtimer_debug_descr);
347 static struct debug_obj_descr hrtimer_debug_descr = {
349 .debug_hint = hrtimer_debug_hint,
350 .fixup_init = hrtimer_fixup_init,
351 .fixup_activate = hrtimer_fixup_activate,
352 .fixup_free = hrtimer_fixup_free,
355 static inline void debug_hrtimer_init(struct hrtimer *timer)
357 debug_object_init(timer, &hrtimer_debug_descr);
360 static inline void debug_hrtimer_activate(struct hrtimer *timer)
362 debug_object_activate(timer, &hrtimer_debug_descr);
365 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
367 debug_object_deactivate(timer, &hrtimer_debug_descr);
370 static inline void debug_hrtimer_free(struct hrtimer *timer)
372 debug_object_free(timer, &hrtimer_debug_descr);
375 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
376 enum hrtimer_mode mode);
378 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
379 enum hrtimer_mode mode)
381 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
382 __hrtimer_init(timer, clock_id, mode);
384 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
386 void destroy_hrtimer_on_stack(struct hrtimer *timer)
388 debug_object_free(timer, &hrtimer_debug_descr);
392 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
393 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
394 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
398 debug_init(struct hrtimer *timer, clockid_t clockid,
399 enum hrtimer_mode mode)
401 debug_hrtimer_init(timer);
402 trace_hrtimer_init(timer, clockid, mode);
405 static inline void debug_activate(struct hrtimer *timer)
407 debug_hrtimer_activate(timer);
408 trace_hrtimer_start(timer);
411 static inline void debug_deactivate(struct hrtimer *timer)
413 debug_hrtimer_deactivate(timer);
414 trace_hrtimer_cancel(timer);
417 #if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
418 static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
420 struct hrtimer_clock_base *base = cpu_base->clock_base;
421 ktime_t expires, expires_next = { .tv64 = KTIME_MAX };
422 unsigned int active = cpu_base->active_bases;
424 for (; active; base++, active >>= 1) {
425 struct timerqueue_node *next;
426 struct hrtimer *timer;
428 if (!(active & 0x01))
431 next = timerqueue_getnext(&base->active);
432 timer = container_of(next, struct hrtimer, node);
433 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
434 if (expires.tv64 < expires_next.tv64)
435 expires_next = expires;
438 * clock_was_set() might have changed base->offset of any of
439 * the clock bases so the result might be negative. Fix it up
440 * to prevent a false positive in clockevents_program_event().
442 if (expires_next.tv64 < 0)
443 expires_next.tv64 = 0;
448 static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
450 ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
451 ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
452 ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
454 return ktime_get_update_offsets_now(&base->clock_was_set_seq,
455 offs_real, offs_boot, offs_tai);
458 /* High resolution timer related functions */
459 #ifdef CONFIG_HIGH_RES_TIMERS
462 * High resolution timer enabled ?
464 static int hrtimer_hres_enabled __read_mostly = 1;
465 unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
466 EXPORT_SYMBOL_GPL(hrtimer_resolution);
469 * Enable / Disable high resolution mode
471 static int __init setup_hrtimer_hres(char *str)
473 if (!strcmp(str, "off"))
474 hrtimer_hres_enabled = 0;
475 else if (!strcmp(str, "on"))
476 hrtimer_hres_enabled = 1;
482 __setup("highres=", setup_hrtimer_hres);
485 * hrtimer_high_res_enabled - query, if the highres mode is enabled
487 static inline int hrtimer_is_hres_enabled(void)
489 return hrtimer_hres_enabled;
493 * Is the high resolution mode active ?
495 static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base)
497 return cpu_base->hres_active;
500 static inline int hrtimer_hres_active(void)
502 return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases));
506 * Reprogram the event source with checking both queues for the
508 * Called with interrupts disabled and base->lock held
511 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
513 ktime_t expires_next;
515 if (!cpu_base->hres_active)
518 expires_next = __hrtimer_get_next_event(cpu_base);
520 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
523 cpu_base->expires_next.tv64 = expires_next.tv64;
526 * If a hang was detected in the last timer interrupt then we
527 * leave the hang delay active in the hardware. We want the
528 * system to make progress. That also prevents the following
530 * T1 expires 50ms from now
531 * T2 expires 5s from now
533 * T1 is removed, so this code is called and would reprogram
534 * the hardware to 5s from now. Any hrtimer_start after that
535 * will not reprogram the hardware due to hang_detected being
536 * set. So we'd effectivly block all timers until the T2 event
539 if (cpu_base->hang_detected)
542 if (cpu_base->expires_next.tv64 != KTIME_MAX)
543 tick_program_event(cpu_base->expires_next, 1);
547 * Shared reprogramming for clock_realtime and clock_monotonic
549 * When a timer is enqueued and expires earlier than the already enqueued
550 * timers, we have to check, whether it expires earlier than the timer for
551 * which the clock event device was armed.
553 * Note, that in case the state has HRTIMER_STATE_CALLBACK set, no reprogramming
554 * and no expiry check happens. The timer gets enqueued into the rbtree. The
555 * reprogramming and expiry check is done in the hrtimer_interrupt or in the
558 * Called with interrupts disabled and base->cpu_base.lock held
560 static int hrtimer_reprogram(struct hrtimer *timer,
561 struct hrtimer_clock_base *base)
563 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
564 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
567 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
570 * When the callback is running, we do not reprogram the clock event
571 * device. The timer callback is either running on a different CPU or
572 * the callback is executed in the hrtimer_interrupt context. The
573 * reprogramming is handled either by the softirq, which called the
574 * callback or at the end of the hrtimer_interrupt.
576 if (hrtimer_callback_running(timer))
580 * CLOCK_REALTIME timer might be requested with an absolute
581 * expiry time which is less than base->offset. Nothing wrong
582 * about that, just avoid to call into the tick code, which
583 * has now objections against negative expiry values.
585 if (expires.tv64 < 0)
588 if (expires.tv64 >= cpu_base->expires_next.tv64)
592 * When the target cpu of the timer is currently executing
593 * hrtimer_interrupt(), then we do not touch the clock event
594 * device. hrtimer_interrupt() will reevaluate all clock bases
595 * before reprogramming the device.
597 if (cpu_base->in_hrtirq)
601 * If a hang was detected in the last timer interrupt then we
602 * do not schedule a timer which is earlier than the expiry
603 * which we enforced in the hang detection. We want the system
606 if (cpu_base->hang_detected)
610 * Clockevents returns -ETIME, when the event was in the past.
612 res = tick_program_event(expires, 0);
613 if (!IS_ERR_VALUE(res))
614 cpu_base->expires_next = expires;
619 * Initialize the high resolution related parts of cpu_base
621 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
623 base->expires_next.tv64 = KTIME_MAX;
624 base->hres_active = 0;
628 * Retrigger next event is called after clock was set
630 * Called with interrupts disabled via on_each_cpu()
632 static void retrigger_next_event(void *arg)
634 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
636 if (!base->hres_active)
639 raw_spin_lock(&base->lock);
640 hrtimer_update_base(base);
641 hrtimer_force_reprogram(base, 0);
642 raw_spin_unlock(&base->lock);
646 * Switch to high resolution mode
648 static int hrtimer_switch_to_hres(void)
650 int cpu = smp_processor_id();
651 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
654 if (base->hres_active)
657 local_irq_save(flags);
659 if (tick_init_highres()) {
660 local_irq_restore(flags);
661 printk(KERN_WARNING "Could not switch to high resolution "
662 "mode on CPU %d\n", cpu);
665 base->hres_active = 1;
666 hrtimer_resolution = HIGH_RES_NSEC;
668 tick_setup_sched_timer();
669 /* "Retrigger" the interrupt to get things going */
670 retrigger_next_event(NULL);
671 local_irq_restore(flags);
675 static void clock_was_set_work(struct work_struct *work)
680 static DECLARE_WORK(hrtimer_work, clock_was_set_work);
683 * Called from timekeeping and resume code to reprogramm the hrtimer
684 * interrupt device on all cpus.
686 void clock_was_set_delayed(void)
688 schedule_work(&hrtimer_work);
693 static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *b) { return 0; }
694 static inline int hrtimer_hres_active(void) { return 0; }
695 static inline int hrtimer_is_hres_enabled(void) { return 0; }
696 static inline int hrtimer_switch_to_hres(void) { return 0; }
698 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
699 static inline int hrtimer_reprogram(struct hrtimer *timer,
700 struct hrtimer_clock_base *base)
704 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
705 static inline void retrigger_next_event(void *arg) { }
707 #endif /* CONFIG_HIGH_RES_TIMERS */
710 * Clock realtime was set
712 * Change the offset of the realtime clock vs. the monotonic
715 * We might have to reprogram the high resolution timer interrupt. On
716 * SMP we call the architecture specific code to retrigger _all_ high
717 * resolution timer interrupts. On UP we just disable interrupts and
718 * call the high resolution interrupt code.
720 void clock_was_set(void)
722 #ifdef CONFIG_HIGH_RES_TIMERS
723 /* Retrigger the CPU local events everywhere */
724 on_each_cpu(retrigger_next_event, NULL, 1);
726 timerfd_clock_was_set();
730 * During resume we might have to reprogram the high resolution timer
731 * interrupt on all online CPUs. However, all other CPUs will be
732 * stopped with IRQs interrupts disabled so the clock_was_set() call
735 void hrtimers_resume(void)
737 WARN_ONCE(!irqs_disabled(),
738 KERN_INFO "hrtimers_resume() called with IRQs enabled!");
740 /* Retrigger on the local CPU */
741 retrigger_next_event(NULL);
742 /* And schedule a retrigger for all others */
743 clock_was_set_delayed();
746 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
748 #ifdef CONFIG_TIMER_STATS
749 if (timer->start_site)
751 timer->start_site = __builtin_return_address(0);
752 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
753 timer->start_pid = current->pid;
757 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
759 #ifdef CONFIG_TIMER_STATS
760 timer->start_site = NULL;
764 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
766 #ifdef CONFIG_TIMER_STATS
767 if (likely(!timer_stats_active))
769 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
770 timer->function, timer->start_comm, 0);
775 * Counterpart to lock_hrtimer_base above:
778 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
780 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
784 * hrtimer_forward - forward the timer expiry
785 * @timer: hrtimer to forward
786 * @now: forward past this time
787 * @interval: the interval to forward
789 * Forward the timer expiry so it will expire in the future.
790 * Returns the number of overruns.
792 * Can be safely called from the callback function of @timer. If
793 * called from other contexts @timer must neither be enqueued nor
794 * running the callback and the caller needs to take care of
797 * Note: This only updates the timer expiry value and does not requeue
800 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
805 delta = ktime_sub(now, hrtimer_get_expires(timer));
810 if (interval.tv64 < hrtimer_resolution)
811 interval.tv64 = hrtimer_resolution;
813 if (unlikely(delta.tv64 >= interval.tv64)) {
814 s64 incr = ktime_to_ns(interval);
816 orun = ktime_divns(delta, incr);
817 hrtimer_add_expires_ns(timer, incr * orun);
818 if (hrtimer_get_expires_tv64(timer) > now.tv64)
821 * This (and the ktime_add() below) is the
822 * correction for exact:
826 hrtimer_add_expires(timer, interval);
830 EXPORT_SYMBOL_GPL(hrtimer_forward);
833 * enqueue_hrtimer - internal function to (re)start a timer
835 * The timer is inserted in expiry order. Insertion into the
836 * red black tree is O(log(n)). Must hold the base lock.
838 * Returns 1 when the new timer is the leftmost timer in the tree.
840 static int enqueue_hrtimer(struct hrtimer *timer,
841 struct hrtimer_clock_base *base)
843 debug_activate(timer);
845 timerqueue_add(&base->active, &timer->node);
846 base->cpu_base->active_bases |= 1 << base->index;
849 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
850 * state of a possibly running callback.
852 timer->state |= HRTIMER_STATE_ENQUEUED;
854 return (&timer->node == base->active.next);
858 * __remove_hrtimer - internal function to remove a timer
860 * Caller must hold the base lock.
862 * High resolution timer mode reprograms the clock event device when the
863 * timer is the one which expires next. The caller can disable this by setting
864 * reprogram to zero. This is useful, when the context does a reprogramming
865 * anyway (e.g. timer interrupt)
867 static void __remove_hrtimer(struct hrtimer *timer,
868 struct hrtimer_clock_base *base,
869 unsigned long newstate, int reprogram)
871 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
872 struct timerqueue_node *next_timer;
874 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
877 next_timer = timerqueue_getnext(&base->active);
878 timerqueue_del(&base->active, &timer->node);
879 if (!timerqueue_getnext(&base->active))
880 cpu_base->active_bases &= ~(1 << base->index);
882 if (&timer->node == next_timer) {
883 #ifdef CONFIG_HIGH_RES_TIMERS
884 /* Reprogram the clock event device. if enabled */
885 if (reprogram && cpu_base->hres_active) {
888 expires = ktime_sub(hrtimer_get_expires(timer),
890 if (cpu_base->expires_next.tv64 == expires.tv64)
891 hrtimer_force_reprogram(cpu_base, 1);
896 timer->state = newstate;
900 * remove hrtimer, called with base lock held
903 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
905 if (hrtimer_is_queued(timer)) {
910 * Remove the timer and force reprogramming when high
911 * resolution mode is active and the timer is on the current
912 * CPU. If we remove a timer on another CPU, reprogramming is
913 * skipped. The interrupt event on this CPU is fired and
914 * reprogramming happens in the interrupt handler. This is a
915 * rare case and less expensive than a smp call.
917 debug_deactivate(timer);
918 timer_stats_hrtimer_clear_start_info(timer);
919 reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
921 * We must preserve the CALLBACK state flag here,
922 * otherwise we could move the timer base in
923 * switch_hrtimer_base.
925 state = timer->state & HRTIMER_STATE_CALLBACK;
926 __remove_hrtimer(timer, base, state, reprogram);
932 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
933 unsigned long delta_ns, const enum hrtimer_mode mode,
936 struct hrtimer_clock_base *base, *new_base;
940 base = lock_hrtimer_base(timer, &flags);
942 /* Remove an active timer from the queue: */
943 ret = remove_hrtimer(timer, base);
945 if (mode & HRTIMER_MODE_REL) {
946 tim = ktime_add_safe(tim, base->get_time());
948 * CONFIG_TIME_LOW_RES is a temporary way for architectures
949 * to signal that they simply return xtime in
950 * do_gettimeoffset(). In this case we want to round up by
951 * resolution when starting a relative timer, to avoid short
952 * timeouts. This will go away with the GTOD framework.
954 #ifdef CONFIG_TIME_LOW_RES
955 tim = ktime_add_safe(tim, ktime_set(0, hrtimer_resolution));
959 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
961 /* Switch the timer base, if necessary: */
962 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
964 timer_stats_hrtimer_set_start_info(timer);
966 leftmost = enqueue_hrtimer(timer, new_base);
969 unlock_hrtimer_base(timer, &flags);
973 if (!hrtimer_is_hres_active(timer)) {
975 * Kick to reschedule the next tick to handle the new timer
976 * on dynticks target.
978 wake_up_nohz_cpu(new_base->cpu_base->cpu);
979 } else if (new_base->cpu_base == this_cpu_ptr(&hrtimer_bases) &&
980 hrtimer_reprogram(timer, new_base)) {
982 * Only allow reprogramming if the new base is on this CPU.
983 * (it might still be on another CPU if the timer was pending)
985 * XXX send_remote_softirq() ?
989 * We need to drop cpu_base->lock to avoid a
990 * lock ordering issue vs. rq->lock.
992 raw_spin_unlock(&new_base->cpu_base->lock);
993 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
994 local_irq_restore(flags);
997 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1001 unlock_hrtimer_base(timer, &flags);
1005 EXPORT_SYMBOL_GPL(__hrtimer_start_range_ns);
1008 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
1009 * @timer: the timer to be added
1011 * @delta_ns: "slack" range for the timer
1012 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
1013 * relative (HRTIMER_MODE_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_MODE_ABS) or
1031 * relative (HRTIMER_MODE_REL)
1035 * 1 when the timer was active
1038 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1040 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1042 EXPORT_SYMBOL_GPL(hrtimer_start);
1046 * hrtimer_try_to_cancel - try to deactivate a timer
1047 * @timer: hrtimer to stop
1050 * 0 when the timer was not active
1051 * 1 when the timer was active
1052 * -1 when the timer is currently excuting the callback function and
1055 int hrtimer_try_to_cancel(struct hrtimer *timer)
1057 struct hrtimer_clock_base *base;
1058 unsigned long flags;
1061 base = lock_hrtimer_base(timer, &flags);
1063 if (!hrtimer_callback_running(timer))
1064 ret = remove_hrtimer(timer, base);
1066 unlock_hrtimer_base(timer, &flags);
1071 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1074 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1075 * @timer: the timer to be cancelled
1078 * 0 when the timer was not active
1079 * 1 when the timer was active
1081 int hrtimer_cancel(struct hrtimer *timer)
1084 int ret = hrtimer_try_to_cancel(timer);
1091 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1094 * hrtimer_get_remaining - get remaining time for the timer
1095 * @timer: the timer to read
1097 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1099 unsigned long flags;
1102 lock_hrtimer_base(timer, &flags);
1103 rem = hrtimer_expires_remaining(timer);
1104 unlock_hrtimer_base(timer, &flags);
1108 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1110 #ifdef CONFIG_NO_HZ_COMMON
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 = this_cpu_ptr(&hrtimer_bases);
1120 ktime_t mindelta = { .tv64 = KTIME_MAX };
1121 unsigned long flags;
1123 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1125 if (!__hrtimer_hres_active(cpu_base))
1126 mindelta = ktime_sub(__hrtimer_get_next_event(cpu_base),
1129 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1131 if (mindelta.tv64 < 0)
1137 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1138 enum hrtimer_mode mode)
1140 struct hrtimer_cpu_base *cpu_base;
1143 memset(timer, 0, sizeof(struct hrtimer));
1145 cpu_base = raw_cpu_ptr(&hrtimer_bases);
1147 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1148 clock_id = CLOCK_MONOTONIC;
1150 base = hrtimer_clockid_to_base(clock_id);
1151 timer->base = &cpu_base->clock_base[base];
1152 timerqueue_init(&timer->node);
1154 #ifdef CONFIG_TIMER_STATS
1155 timer->start_site = NULL;
1156 timer->start_pid = -1;
1157 memset(timer->start_comm, 0, TASK_COMM_LEN);
1162 * hrtimer_init - initialize a timer to the given clock
1163 * @timer: the timer to be initialized
1164 * @clock_id: the clock to be used
1165 * @mode: timer mode abs/rel
1167 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1168 enum hrtimer_mode mode)
1170 debug_init(timer, clock_id, mode);
1171 __hrtimer_init(timer, clock_id, mode);
1173 EXPORT_SYMBOL_GPL(hrtimer_init);
1175 static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
1176 struct hrtimer_clock_base *base,
1177 struct hrtimer *timer, ktime_t *now)
1179 enum hrtimer_restart (*fn)(struct hrtimer *);
1182 WARN_ON(!irqs_disabled());
1184 debug_deactivate(timer);
1185 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1186 timer_stats_account_hrtimer(timer);
1187 fn = timer->function;
1190 * Because we run timers from hardirq context, there is no chance
1191 * they get migrated to another cpu, therefore its safe to unlock
1194 raw_spin_unlock(&cpu_base->lock);
1195 trace_hrtimer_expire_entry(timer, now);
1196 restart = fn(timer);
1197 trace_hrtimer_expire_exit(timer);
1198 raw_spin_lock(&cpu_base->lock);
1201 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1202 * we do not reprogramm the event hardware. Happens either in
1203 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1205 if (restart != HRTIMER_NORESTART) {
1206 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1207 enqueue_hrtimer(timer, base);
1210 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1212 timer->state &= ~HRTIMER_STATE_CALLBACK;
1215 static void __hrtimer_run_queues(struct hrtimer_cpu_base *cpu_base, ktime_t now)
1217 struct hrtimer_clock_base *base = cpu_base->clock_base;
1218 unsigned int active = cpu_base->active_bases;
1220 for (; active; base++, active >>= 1) {
1221 struct timerqueue_node *node;
1224 if (!(active & 0x01))
1227 basenow = ktime_add(now, base->offset);
1229 while ((node = timerqueue_getnext(&base->active))) {
1230 struct hrtimer *timer;
1232 timer = container_of(node, struct hrtimer, node);
1235 * The immediate goal for using the softexpires is
1236 * minimizing wakeups, not running timers at the
1237 * earliest interrupt after their soft expiration.
1238 * This allows us to avoid using a Priority Search
1239 * Tree, which can answer a stabbing querry for
1240 * overlapping intervals and instead use the simple
1241 * BST we already have.
1242 * We don't add extra wakeups by delaying timers that
1243 * are right-of a not yet expired timer, because that
1244 * timer will have to trigger a wakeup anyway.
1246 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer))
1249 __run_hrtimer(cpu_base, base, timer, &basenow);
1254 #ifdef CONFIG_HIGH_RES_TIMERS
1257 * High resolution timer interrupt
1258 * Called with interrupts disabled
1260 void hrtimer_interrupt(struct clock_event_device *dev)
1262 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1263 ktime_t expires_next, now, entry_time, delta;
1266 BUG_ON(!cpu_base->hres_active);
1267 cpu_base->nr_events++;
1268 dev->next_event.tv64 = KTIME_MAX;
1270 raw_spin_lock(&cpu_base->lock);
1271 entry_time = now = hrtimer_update_base(cpu_base);
1273 cpu_base->in_hrtirq = 1;
1275 * We set expires_next to KTIME_MAX here with cpu_base->lock
1276 * held to prevent that a timer is enqueued in our queue via
1277 * the migration code. This does not affect enqueueing of
1278 * timers which run their callback and need to be requeued on
1281 cpu_base->expires_next.tv64 = KTIME_MAX;
1283 __hrtimer_run_queues(cpu_base, now);
1285 /* Reevaluate the clock bases for the next expiry */
1286 expires_next = __hrtimer_get_next_event(cpu_base);
1288 * Store the new expiry value so the migration code can verify
1291 cpu_base->expires_next = expires_next;
1292 cpu_base->in_hrtirq = 0;
1293 raw_spin_unlock(&cpu_base->lock);
1295 /* Reprogramming necessary ? */
1296 if (expires_next.tv64 == KTIME_MAX ||
1297 !tick_program_event(expires_next, 0)) {
1298 cpu_base->hang_detected = 0;
1303 * The next timer was already expired due to:
1305 * - long lasting callbacks
1306 * - being scheduled away when running in a VM
1308 * We need to prevent that we loop forever in the hrtimer
1309 * interrupt routine. We give it 3 attempts to avoid
1310 * overreacting on some spurious event.
1312 * Acquire base lock for updating the offsets and retrieving
1315 raw_spin_lock(&cpu_base->lock);
1316 now = hrtimer_update_base(cpu_base);
1317 cpu_base->nr_retries++;
1321 * Give the system a chance to do something else than looping
1322 * here. We stored the entry time, so we know exactly how long
1323 * we spent here. We schedule the next event this amount of
1326 cpu_base->nr_hangs++;
1327 cpu_base->hang_detected = 1;
1328 raw_spin_unlock(&cpu_base->lock);
1329 delta = ktime_sub(now, entry_time);
1330 if ((unsigned int)delta.tv64 > cpu_base->max_hang_time)
1331 cpu_base->max_hang_time = (unsigned int) delta.tv64;
1333 * Limit it to a sensible value as we enforce a longer
1334 * delay. Give the CPU at least 100ms to catch up.
1336 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1337 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1339 expires_next = ktime_add(now, delta);
1340 tick_program_event(expires_next, 1);
1341 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1342 ktime_to_ns(delta));
1346 * local version of hrtimer_peek_ahead_timers() called with interrupts
1349 static void __hrtimer_peek_ahead_timers(void)
1351 struct tick_device *td;
1353 if (!hrtimer_hres_active())
1356 td = this_cpu_ptr(&tick_cpu_device);
1357 if (td && td->evtdev)
1358 hrtimer_interrupt(td->evtdev);
1362 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1364 * hrtimer_peek_ahead_timers will peek at the timer queue of
1365 * the current cpu and check if there are any timers for which
1366 * the soft expires time has passed. If any such timers exist,
1367 * they are run immediately and then removed from the timer queue.
1370 void hrtimer_peek_ahead_timers(void)
1372 unsigned long flags;
1374 local_irq_save(flags);
1375 __hrtimer_peek_ahead_timers();
1376 local_irq_restore(flags);
1379 static void run_hrtimer_softirq(struct softirq_action *h)
1381 hrtimer_peek_ahead_timers();
1384 #else /* CONFIG_HIGH_RES_TIMERS */
1386 static inline void __hrtimer_peek_ahead_timers(void) { }
1388 #endif /* !CONFIG_HIGH_RES_TIMERS */
1391 * Called from timer softirq every jiffy, expire hrtimers:
1393 * For HRT its the fall back code to run the softirq in the timer
1394 * softirq context in case the hrtimer initialization failed or has
1395 * not been done yet.
1397 void hrtimer_run_pending(void)
1399 if (hrtimer_hres_active())
1403 * This _is_ ugly: We have to check in the softirq context,
1404 * whether we can switch to highres and / or nohz mode. The
1405 * clocksource switch happens in the timer interrupt with
1406 * xtime_lock held. Notification from there only sets the
1407 * check bit in the tick_oneshot code, otherwise we might
1408 * deadlock vs. xtime_lock.
1410 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1411 hrtimer_switch_to_hres();
1415 * Called from hardirq context every jiffy
1417 void hrtimer_run_queues(void)
1419 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1422 if (__hrtimer_hres_active(cpu_base))
1425 raw_spin_lock(&cpu_base->lock);
1426 now = hrtimer_update_base(cpu_base);
1427 __hrtimer_run_queues(cpu_base, now);
1428 raw_spin_unlock(&cpu_base->lock);
1432 * Sleep related functions:
1434 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1436 struct hrtimer_sleeper *t =
1437 container_of(timer, struct hrtimer_sleeper, timer);
1438 struct task_struct *task = t->task;
1442 wake_up_process(task);
1444 return HRTIMER_NORESTART;
1447 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1449 sl->timer.function = hrtimer_wakeup;
1452 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1454 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1456 hrtimer_init_sleeper(t, current);
1459 set_current_state(TASK_INTERRUPTIBLE);
1460 hrtimer_start_expires(&t->timer, mode);
1461 if (!hrtimer_active(&t->timer))
1464 if (likely(t->task))
1465 freezable_schedule();
1467 hrtimer_cancel(&t->timer);
1468 mode = HRTIMER_MODE_ABS;
1470 } while (t->task && !signal_pending(current));
1472 __set_current_state(TASK_RUNNING);
1474 return t->task == NULL;
1477 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1479 struct timespec rmt;
1482 rem = hrtimer_expires_remaining(timer);
1485 rmt = ktime_to_timespec(rem);
1487 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1493 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1495 struct hrtimer_sleeper t;
1496 struct timespec __user *rmtp;
1499 hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
1501 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1503 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1506 rmtp = restart->nanosleep.rmtp;
1508 ret = update_rmtp(&t.timer, rmtp);
1513 /* The other values in restart are already filled in */
1514 ret = -ERESTART_RESTARTBLOCK;
1516 destroy_hrtimer_on_stack(&t.timer);
1520 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1521 const enum hrtimer_mode mode, const clockid_t clockid)
1523 struct restart_block *restart;
1524 struct hrtimer_sleeper t;
1526 unsigned long slack;
1528 slack = current->timer_slack_ns;
1529 if (dl_task(current) || rt_task(current))
1532 hrtimer_init_on_stack(&t.timer, clockid, mode);
1533 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1534 if (do_nanosleep(&t, mode))
1537 /* Absolute timers do not update the rmtp value and restart: */
1538 if (mode == HRTIMER_MODE_ABS) {
1539 ret = -ERESTARTNOHAND;
1544 ret = update_rmtp(&t.timer, rmtp);
1549 restart = ¤t->restart_block;
1550 restart->fn = hrtimer_nanosleep_restart;
1551 restart->nanosleep.clockid = t.timer.base->clockid;
1552 restart->nanosleep.rmtp = rmtp;
1553 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1555 ret = -ERESTART_RESTARTBLOCK;
1557 destroy_hrtimer_on_stack(&t.timer);
1561 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1562 struct timespec __user *, rmtp)
1566 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1569 if (!timespec_valid(&tu))
1572 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1576 * Functions related to boot-time initialization:
1578 static void init_hrtimers_cpu(int cpu)
1580 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1583 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1584 cpu_base->clock_base[i].cpu_base = cpu_base;
1585 timerqueue_init_head(&cpu_base->clock_base[i].active);
1588 cpu_base->cpu = cpu;
1589 hrtimer_init_hres(cpu_base);
1592 #ifdef CONFIG_HOTPLUG_CPU
1594 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1595 struct hrtimer_clock_base *new_base)
1597 struct hrtimer *timer;
1598 struct timerqueue_node *node;
1600 while ((node = timerqueue_getnext(&old_base->active))) {
1601 timer = container_of(node, struct hrtimer, node);
1602 BUG_ON(hrtimer_callback_running(timer));
1603 debug_deactivate(timer);
1606 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1607 * timer could be seen as !active and just vanish away
1608 * under us on another CPU
1610 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1611 timer->base = new_base;
1613 * Enqueue the timers on the new cpu. This does not
1614 * reprogram the event device in case the timer
1615 * expires before the earliest on this CPU, but we run
1616 * hrtimer_interrupt after we migrated everything to
1617 * sort out already expired timers and reprogram the
1620 enqueue_hrtimer(timer, new_base);
1622 /* Clear the migration state bit */
1623 timer->state &= ~HRTIMER_STATE_MIGRATE;
1627 static void migrate_hrtimers(int scpu)
1629 struct hrtimer_cpu_base *old_base, *new_base;
1632 BUG_ON(cpu_online(scpu));
1633 tick_cancel_sched_timer(scpu);
1635 local_irq_disable();
1636 old_base = &per_cpu(hrtimer_bases, scpu);
1637 new_base = this_cpu_ptr(&hrtimer_bases);
1639 * The caller is globally serialized and nobody else
1640 * takes two locks at once, deadlock is not possible.
1642 raw_spin_lock(&new_base->lock);
1643 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1645 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1646 migrate_hrtimer_list(&old_base->clock_base[i],
1647 &new_base->clock_base[i]);
1650 raw_spin_unlock(&old_base->lock);
1651 raw_spin_unlock(&new_base->lock);
1653 /* Check, if we got expired work to do */
1654 __hrtimer_peek_ahead_timers();
1658 #endif /* CONFIG_HOTPLUG_CPU */
1660 static int hrtimer_cpu_notify(struct notifier_block *self,
1661 unsigned long action, void *hcpu)
1663 int scpu = (long)hcpu;
1667 case CPU_UP_PREPARE:
1668 case CPU_UP_PREPARE_FROZEN:
1669 init_hrtimers_cpu(scpu);
1672 #ifdef CONFIG_HOTPLUG_CPU
1674 case CPU_DEAD_FROZEN:
1675 migrate_hrtimers(scpu);
1686 static struct notifier_block hrtimers_nb = {
1687 .notifier_call = hrtimer_cpu_notify,
1690 void __init hrtimers_init(void)
1692 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1693 (void *)(long)smp_processor_id());
1694 register_cpu_notifier(&hrtimers_nb);
1695 #ifdef CONFIG_HIGH_RES_TIMERS
1696 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1701 * schedule_hrtimeout_range_clock - sleep until timeout
1702 * @expires: timeout value (ktime_t)
1703 * @delta: slack in expires timeout (ktime_t)
1704 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1705 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1708 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1709 const enum hrtimer_mode mode, int clock)
1711 struct hrtimer_sleeper t;
1714 * Optimize when a zero timeout value is given. It does not
1715 * matter whether this is an absolute or a relative time.
1717 if (expires && !expires->tv64) {
1718 __set_current_state(TASK_RUNNING);
1723 * A NULL parameter means "infinite"
1730 hrtimer_init_on_stack(&t.timer, clock, mode);
1731 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1733 hrtimer_init_sleeper(&t, current);
1735 hrtimer_start_expires(&t.timer, mode);
1736 if (!hrtimer_active(&t.timer))
1742 hrtimer_cancel(&t.timer);
1743 destroy_hrtimer_on_stack(&t.timer);
1745 __set_current_state(TASK_RUNNING);
1747 return !t.task ? 0 : -EINTR;
1751 * schedule_hrtimeout_range - 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
1756 * Make the current task sleep until the given expiry time has
1757 * elapsed. The routine will return immediately unless
1758 * the current task state has been set (see set_current_state()).
1760 * The @delta argument gives the kernel the freedom to schedule the
1761 * actual wakeup to a time that is both power and performance friendly.
1762 * The kernel give the normal best effort behavior for "@expires+@delta",
1763 * but may decide to fire the timer earlier, but no earlier than @expires.
1765 * You can set the task state as follows -
1767 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1768 * pass before the routine returns.
1770 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1771 * delivered to the current task.
1773 * The current task state is guaranteed to be TASK_RUNNING when this
1776 * Returns 0 when the timer has expired otherwise -EINTR
1778 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1779 const enum hrtimer_mode mode)
1781 return schedule_hrtimeout_range_clock(expires, delta, mode,
1784 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1787 * schedule_hrtimeout - sleep until timeout
1788 * @expires: timeout value (ktime_t)
1789 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1791 * Make the current task sleep until the given expiry time has
1792 * elapsed. The routine will return immediately unless
1793 * the current task state has been set (see set_current_state()).
1795 * You can set the task state as follows -
1797 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1798 * pass before the routine returns.
1800 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1801 * delivered to the current task.
1803 * The current task state is guaranteed to be TASK_RUNNING when this
1806 * Returns 0 when the timer has expired otherwise -EINTR
1808 int __sched schedule_hrtimeout(ktime_t *expires,
1809 const enum hrtimer_mode mode)
1811 return schedule_hrtimeout_range(expires, 0, mode);
1813 EXPORT_SYMBOL_GPL(schedule_hrtimeout);