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];
109 * Get the coarse grained time at the softirq based on xtime and
112 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
114 ktime_t xtim, mono, boot, tai;
115 ktime_t off_real, off_boot, off_tai;
117 mono = ktime_get_update_offsets_tick(&off_real, &off_boot, &off_tai);
118 boot = ktime_add(mono, off_boot);
119 xtim = ktime_add(mono, off_real);
120 tai = ktime_add(mono, off_tai);
122 base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
123 base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
124 base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
125 base->clock_base[HRTIMER_BASE_TAI].softirq_time = tai;
129 * Functions and macros which are different for UP/SMP systems are kept in a
135 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
136 * means that all timers which are tied to this base via timer->base are
137 * locked, and the base itself is locked too.
139 * So __run_timers/migrate_timers can safely modify all timers which could
140 * be found on the lists/queues.
142 * When the timer's base is locked, and the timer removed from list, it is
143 * possible to set timer->base = NULL and drop the lock: the timer remains
147 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
148 unsigned long *flags)
150 struct hrtimer_clock_base *base;
154 if (likely(base != NULL)) {
155 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
156 if (likely(base == timer->base))
158 /* The timer has migrated to another CPU: */
159 raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
166 * With HIGHRES=y we do not migrate the timer when it is expiring
167 * before the next event on the target cpu because we cannot reprogram
168 * the target cpu hardware and we would cause it to fire late.
170 * Called with cpu_base->lock of target cpu held.
173 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
175 #ifdef CONFIG_HIGH_RES_TIMERS
178 if (!new_base->cpu_base->hres_active)
181 expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
182 return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
189 * Switch the timer base to the current CPU when possible.
191 static inline struct hrtimer_clock_base *
192 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
195 struct hrtimer_clock_base *new_base;
196 struct hrtimer_cpu_base *new_cpu_base;
197 int this_cpu = smp_processor_id();
198 int cpu = get_nohz_timer_target(pinned);
199 int basenum = base->index;
202 new_cpu_base = &per_cpu(hrtimer_bases, cpu);
203 new_base = &new_cpu_base->clock_base[basenum];
205 if (base != new_base) {
207 * We are trying to move timer to new_base.
208 * However we can't change timer's base while it is running,
209 * so we keep it on the same CPU. No hassle vs. reprogramming
210 * the event source in the high resolution case. The softirq
211 * code will take care of this when the timer function has
212 * completed. There is no conflict as we hold the lock until
213 * the timer is enqueued.
215 if (unlikely(hrtimer_callback_running(timer)))
218 /* See the comment in lock_timer_base() */
220 raw_spin_unlock(&base->cpu_base->lock);
221 raw_spin_lock(&new_base->cpu_base->lock);
223 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
225 raw_spin_unlock(&new_base->cpu_base->lock);
226 raw_spin_lock(&base->cpu_base->lock);
230 timer->base = new_base;
232 if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
240 #else /* CONFIG_SMP */
242 static inline struct hrtimer_clock_base *
243 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
245 struct hrtimer_clock_base *base = timer->base;
247 raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
252 # define switch_hrtimer_base(t, b, p) (b)
254 #endif /* !CONFIG_SMP */
257 * Functions for the union type storage format of ktime_t which are
258 * too large for inlining:
260 #if BITS_PER_LONG < 64
262 * Divide a ktime value by a nanosecond value
264 u64 __ktime_divns(const ktime_t kt, s64 div)
269 dclc = ktime_to_ns(kt);
270 /* Make sure the divisor is less than 2^32: */
276 do_div(dclc, (unsigned long) div);
280 EXPORT_SYMBOL_GPL(__ktime_divns);
281 #endif /* BITS_PER_LONG >= 64 */
284 * Add two ktime values and do a safety check for overflow:
286 ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
288 ktime_t res = ktime_add(lhs, rhs);
291 * We use KTIME_SEC_MAX here, the maximum timeout which we can
292 * return to user space in a timespec:
294 if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
295 res = ktime_set(KTIME_SEC_MAX, 0);
300 EXPORT_SYMBOL_GPL(ktime_add_safe);
302 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
304 static struct debug_obj_descr hrtimer_debug_descr;
306 static void *hrtimer_debug_hint(void *addr)
308 return ((struct hrtimer *) addr)->function;
312 * fixup_init is called when:
313 * - an active object is initialized
315 static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
317 struct hrtimer *timer = addr;
320 case ODEBUG_STATE_ACTIVE:
321 hrtimer_cancel(timer);
322 debug_object_init(timer, &hrtimer_debug_descr);
330 * fixup_activate is called when:
331 * - an active object is activated
332 * - an unknown object is activated (might be a statically initialized object)
334 static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
338 case ODEBUG_STATE_NOTAVAILABLE:
342 case ODEBUG_STATE_ACTIVE:
351 * fixup_free is called when:
352 * - an active object is freed
354 static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
356 struct hrtimer *timer = addr;
359 case ODEBUG_STATE_ACTIVE:
360 hrtimer_cancel(timer);
361 debug_object_free(timer, &hrtimer_debug_descr);
368 static struct debug_obj_descr hrtimer_debug_descr = {
370 .debug_hint = hrtimer_debug_hint,
371 .fixup_init = hrtimer_fixup_init,
372 .fixup_activate = hrtimer_fixup_activate,
373 .fixup_free = hrtimer_fixup_free,
376 static inline void debug_hrtimer_init(struct hrtimer *timer)
378 debug_object_init(timer, &hrtimer_debug_descr);
381 static inline void debug_hrtimer_activate(struct hrtimer *timer)
383 debug_object_activate(timer, &hrtimer_debug_descr);
386 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
388 debug_object_deactivate(timer, &hrtimer_debug_descr);
391 static inline void debug_hrtimer_free(struct hrtimer *timer)
393 debug_object_free(timer, &hrtimer_debug_descr);
396 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
397 enum hrtimer_mode mode);
399 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
400 enum hrtimer_mode mode)
402 debug_object_init_on_stack(timer, &hrtimer_debug_descr);
403 __hrtimer_init(timer, clock_id, mode);
405 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
407 void destroy_hrtimer_on_stack(struct hrtimer *timer)
409 debug_object_free(timer, &hrtimer_debug_descr);
413 static inline void debug_hrtimer_init(struct hrtimer *timer) { }
414 static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
415 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
419 debug_init(struct hrtimer *timer, clockid_t clockid,
420 enum hrtimer_mode mode)
422 debug_hrtimer_init(timer);
423 trace_hrtimer_init(timer, clockid, mode);
426 static inline void debug_activate(struct hrtimer *timer)
428 debug_hrtimer_activate(timer);
429 trace_hrtimer_start(timer);
432 static inline void debug_deactivate(struct hrtimer *timer)
434 debug_hrtimer_deactivate(timer);
435 trace_hrtimer_cancel(timer);
438 #if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
439 static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
441 struct hrtimer_clock_base *base = cpu_base->clock_base;
442 ktime_t expires, expires_next = { .tv64 = KTIME_MAX };
445 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
446 struct timerqueue_node *next;
447 struct hrtimer *timer;
449 next = timerqueue_getnext(&base->active);
453 timer = container_of(next, struct hrtimer, node);
454 expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
455 if (expires.tv64 < expires_next.tv64)
456 expires_next = expires;
459 * clock_was_set() might have changed base->offset of any of
460 * the clock bases so the result might be negative. Fix it up
461 * to prevent a false positive in clockevents_program_event().
463 if (expires_next.tv64 < 0)
464 expires_next.tv64 = 0;
469 /* High resolution timer related functions */
470 #ifdef CONFIG_HIGH_RES_TIMERS
473 * High resolution timer enabled ?
475 static int hrtimer_hres_enabled __read_mostly = 1;
476 unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
477 EXPORT_SYMBOL_GPL(hrtimer_resolution);
480 * Enable / Disable high resolution mode
482 static int __init setup_hrtimer_hres(char *str)
484 if (!strcmp(str, "off"))
485 hrtimer_hres_enabled = 0;
486 else if (!strcmp(str, "on"))
487 hrtimer_hres_enabled = 1;
493 __setup("highres=", setup_hrtimer_hres);
496 * hrtimer_high_res_enabled - query, if the highres mode is enabled
498 static inline int hrtimer_is_hres_enabled(void)
500 return hrtimer_hres_enabled;
504 * Is the high resolution mode active ?
506 static inline int hrtimer_hres_active(void)
508 return __this_cpu_read(hrtimer_bases.hres_active);
512 * Reprogram the event source with checking both queues for the
514 * Called with interrupts disabled and base->lock held
517 hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
519 ktime_t expires_next = __hrtimer_get_next_event(cpu_base);
521 if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
524 cpu_base->expires_next.tv64 = expires_next.tv64;
527 * If a hang was detected in the last timer interrupt then we
528 * leave the hang delay active in the hardware. We want the
529 * system to make progress. That also prevents the following
531 * T1 expires 50ms from now
532 * T2 expires 5s from now
534 * T1 is removed, so this code is called and would reprogram
535 * the hardware to 5s from now. Any hrtimer_start after that
536 * will not reprogram the hardware due to hang_detected being
537 * set. So we'd effectivly block all timers until the T2 event
540 if (cpu_base->hang_detected)
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 * Note, that in case the state has HRTIMER_STATE_CALLBACK set, no reprogramming
555 * and no expiry check happens. The timer gets enqueued into the rbtree. The
556 * reprogramming and expiry check is done in the hrtimer_interrupt or in the
559 * Called with interrupts disabled and base->cpu_base.lock held
561 static int hrtimer_reprogram(struct hrtimer *timer,
562 struct hrtimer_clock_base *base)
564 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
565 ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
568 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
571 * When the callback is running, we do not reprogram the clock event
572 * device. The timer callback is either running on a different CPU or
573 * the callback is executed in the hrtimer_interrupt context. The
574 * reprogramming is handled either by the softirq, which called the
575 * callback or at the end of the hrtimer_interrupt.
577 if (hrtimer_callback_running(timer))
581 * CLOCK_REALTIME timer might be requested with an absolute
582 * expiry time which is less than base->offset. Nothing wrong
583 * about that, just avoid to call into the tick code, which
584 * has now objections against negative expiry values.
586 if (expires.tv64 < 0)
589 if (expires.tv64 >= cpu_base->expires_next.tv64)
593 * When the target cpu of the timer is currently executing
594 * hrtimer_interrupt(), then we do not touch the clock event
595 * device. hrtimer_interrupt() will reevaluate all clock bases
596 * before reprogramming the device.
598 if (cpu_base->in_hrtirq)
602 * If a hang was detected in the last timer interrupt then we
603 * do not schedule a timer which is earlier than the expiry
604 * which we enforced in the hang detection. We want the system
607 if (cpu_base->hang_detected)
611 * Clockevents returns -ETIME, when the event was in the past.
613 res = tick_program_event(expires, 0);
614 if (!IS_ERR_VALUE(res))
615 cpu_base->expires_next = expires;
620 * Initialize the high resolution related parts of cpu_base
622 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
624 base->expires_next.tv64 = KTIME_MAX;
625 base->hres_active = 0;
628 static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
630 ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;
631 ktime_t *offs_boot = &base->clock_base[HRTIMER_BASE_BOOTTIME].offset;
632 ktime_t *offs_tai = &base->clock_base[HRTIMER_BASE_TAI].offset;
634 return ktime_get_update_offsets_now(offs_real, offs_boot, offs_tai);
638 * Retrigger next event is called after clock was set
640 * Called with interrupts disabled via on_each_cpu()
642 static void retrigger_next_event(void *arg)
644 struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
646 if (!hrtimer_hres_active())
649 raw_spin_lock(&base->lock);
650 hrtimer_update_base(base);
651 hrtimer_force_reprogram(base, 0);
652 raw_spin_unlock(&base->lock);
656 * Switch to high resolution mode
658 static int hrtimer_switch_to_hres(void)
660 int cpu = smp_processor_id();
661 struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
664 if (base->hres_active)
667 local_irq_save(flags);
669 if (tick_init_highres()) {
670 local_irq_restore(flags);
671 printk(KERN_WARNING "Could not switch to high resolution "
672 "mode on CPU %d\n", cpu);
675 base->hres_active = 1;
676 hrtimer_resolution = HIGH_RES_NSEC;
678 tick_setup_sched_timer();
679 /* "Retrigger" the interrupt to get things going */
680 retrigger_next_event(NULL);
681 local_irq_restore(flags);
685 static void clock_was_set_work(struct work_struct *work)
690 static DECLARE_WORK(hrtimer_work, clock_was_set_work);
693 * Called from timekeeping and resume code to reprogramm the hrtimer
694 * interrupt device on all cpus.
696 void clock_was_set_delayed(void)
698 schedule_work(&hrtimer_work);
703 static inline int hrtimer_hres_active(void) { return 0; }
704 static inline int hrtimer_is_hres_enabled(void) { return 0; }
705 static inline int hrtimer_switch_to_hres(void) { return 0; }
707 hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
708 static inline int hrtimer_reprogram(struct hrtimer *timer,
709 struct hrtimer_clock_base *base)
713 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
714 static inline void retrigger_next_event(void *arg) { }
716 #endif /* CONFIG_HIGH_RES_TIMERS */
719 * Clock realtime was set
721 * Change the offset of the realtime clock vs. the monotonic
724 * We might have to reprogram the high resolution timer interrupt. On
725 * SMP we call the architecture specific code to retrigger _all_ high
726 * resolution timer interrupts. On UP we just disable interrupts and
727 * call the high resolution interrupt code.
729 void clock_was_set(void)
731 #ifdef CONFIG_HIGH_RES_TIMERS
732 /* Retrigger the CPU local events everywhere */
733 on_each_cpu(retrigger_next_event, NULL, 1);
735 timerfd_clock_was_set();
739 * During resume we might have to reprogram the high resolution timer
740 * interrupt on all online CPUs. However, all other CPUs will be
741 * stopped with IRQs interrupts disabled so the clock_was_set() call
744 void hrtimers_resume(void)
746 WARN_ONCE(!irqs_disabled(),
747 KERN_INFO "hrtimers_resume() called with IRQs enabled!");
749 /* Retrigger on the local CPU */
750 retrigger_next_event(NULL);
751 /* And schedule a retrigger for all others */
752 clock_was_set_delayed();
755 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
757 #ifdef CONFIG_TIMER_STATS
758 if (timer->start_site)
760 timer->start_site = __builtin_return_address(0);
761 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
762 timer->start_pid = current->pid;
766 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
768 #ifdef CONFIG_TIMER_STATS
769 timer->start_site = NULL;
773 static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
775 #ifdef CONFIG_TIMER_STATS
776 if (likely(!timer_stats_active))
778 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
779 timer->function, timer->start_comm, 0);
784 * Counterpart to lock_hrtimer_base above:
787 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
789 raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
793 * hrtimer_forward - forward the timer expiry
794 * @timer: hrtimer to forward
795 * @now: forward past this time
796 * @interval: the interval to forward
798 * Forward the timer expiry so it will expire in the future.
799 * Returns the number of overruns.
801 * Can be safely called from the callback function of @timer. If
802 * called from other contexts @timer must neither be enqueued nor
803 * running the callback and the caller needs to take care of
806 * Note: This only updates the timer expiry value and does not requeue
809 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
814 delta = ktime_sub(now, hrtimer_get_expires(timer));
819 if (interval.tv64 < hrtimer_resolution)
820 interval.tv64 = hrtimer_resolution;
822 if (unlikely(delta.tv64 >= interval.tv64)) {
823 s64 incr = ktime_to_ns(interval);
825 orun = ktime_divns(delta, incr);
826 hrtimer_add_expires_ns(timer, incr * orun);
827 if (hrtimer_get_expires_tv64(timer) > now.tv64)
830 * This (and the ktime_add() below) is the
831 * correction for exact:
835 hrtimer_add_expires(timer, interval);
839 EXPORT_SYMBOL_GPL(hrtimer_forward);
842 * enqueue_hrtimer - internal function to (re)start a timer
844 * The timer is inserted in expiry order. Insertion into the
845 * red black tree is O(log(n)). Must hold the base lock.
847 * Returns 1 when the new timer is the leftmost timer in the tree.
849 static int enqueue_hrtimer(struct hrtimer *timer,
850 struct hrtimer_clock_base *base)
852 debug_activate(timer);
854 timerqueue_add(&base->active, &timer->node);
855 base->cpu_base->active_bases |= 1 << base->index;
858 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
859 * state of a possibly running callback.
861 timer->state |= HRTIMER_STATE_ENQUEUED;
863 return (&timer->node == base->active.next);
867 * __remove_hrtimer - internal function to remove a timer
869 * Caller must hold the base lock.
871 * High resolution timer mode reprograms the clock event device when the
872 * timer is the one which expires next. The caller can disable this by setting
873 * reprogram to zero. This is useful, when the context does a reprogramming
874 * anyway (e.g. timer interrupt)
876 static void __remove_hrtimer(struct hrtimer *timer,
877 struct hrtimer_clock_base *base,
878 unsigned long newstate, int reprogram)
880 struct timerqueue_node *next_timer;
881 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
884 next_timer = timerqueue_getnext(&base->active);
885 timerqueue_del(&base->active, &timer->node);
886 if (!timerqueue_getnext(&base->active))
887 base->cpu_base->active_bases &= ~(1 << base->index);
889 if (&timer->node == next_timer) {
890 #ifdef CONFIG_HIGH_RES_TIMERS
891 /* Reprogram the clock event device. if enabled */
892 if (reprogram && hrtimer_hres_active()) {
895 expires = ktime_sub(hrtimer_get_expires(timer),
897 if (base->cpu_base->expires_next.tv64 == expires.tv64)
898 hrtimer_force_reprogram(base->cpu_base, 1);
903 timer->state = newstate;
907 * remove hrtimer, called with base lock held
910 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
912 if (hrtimer_is_queued(timer)) {
917 * Remove the timer and force reprogramming when high
918 * resolution mode is active and the timer is on the current
919 * CPU. If we remove a timer on another CPU, reprogramming is
920 * skipped. The interrupt event on this CPU is fired and
921 * reprogramming happens in the interrupt handler. This is a
922 * rare case and less expensive than a smp call.
924 debug_deactivate(timer);
925 timer_stats_hrtimer_clear_start_info(timer);
926 reprogram = base->cpu_base == this_cpu_ptr(&hrtimer_bases);
928 * We must preserve the CALLBACK state flag here,
929 * otherwise we could move the timer base in
930 * switch_hrtimer_base.
932 state = timer->state & HRTIMER_STATE_CALLBACK;
933 __remove_hrtimer(timer, base, state, reprogram);
939 int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
940 unsigned long delta_ns, const enum hrtimer_mode mode,
943 struct hrtimer_clock_base *base, *new_base;
947 base = lock_hrtimer_base(timer, &flags);
949 /* Remove an active timer from the queue: */
950 ret = remove_hrtimer(timer, base);
952 if (mode & HRTIMER_MODE_REL) {
953 tim = ktime_add_safe(tim, base->get_time());
955 * CONFIG_TIME_LOW_RES is a temporary way for architectures
956 * to signal that they simply return xtime in
957 * do_gettimeoffset(). In this case we want to round up by
958 * resolution when starting a relative timer, to avoid short
959 * timeouts. This will go away with the GTOD framework.
961 #ifdef CONFIG_TIME_LOW_RES
962 tim = ktime_add_safe(tim, ktime_set(0, hrtimer_resolution));
966 hrtimer_set_expires_range_ns(timer, tim, delta_ns);
968 /* Switch the timer base, if necessary: */
969 new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
971 timer_stats_hrtimer_set_start_info(timer);
973 leftmost = enqueue_hrtimer(timer, new_base);
976 unlock_hrtimer_base(timer, &flags);
980 if (!hrtimer_is_hres_active(timer)) {
982 * Kick to reschedule the next tick to handle the new timer
983 * on dynticks target.
985 wake_up_nohz_cpu(new_base->cpu_base->cpu);
986 } else if (new_base->cpu_base == this_cpu_ptr(&hrtimer_bases) &&
987 hrtimer_reprogram(timer, new_base)) {
989 * Only allow reprogramming if the new base is on this CPU.
990 * (it might still be on another CPU if the timer was pending)
992 * XXX send_remote_softirq() ?
996 * We need to drop cpu_base->lock to avoid a
997 * lock ordering issue vs. rq->lock.
999 raw_spin_unlock(&new_base->cpu_base->lock);
1000 raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1001 local_irq_restore(flags);
1004 __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
1008 unlock_hrtimer_base(timer, &flags);
1012 EXPORT_SYMBOL_GPL(__hrtimer_start_range_ns);
1015 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
1016 * @timer: the timer to be added
1018 * @delta_ns: "slack" range for the timer
1019 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
1020 * relative (HRTIMER_MODE_REL)
1024 * 1 when the timer was active
1026 int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1027 unsigned long delta_ns, const enum hrtimer_mode mode)
1029 return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1031 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1034 * hrtimer_start - (re)start an hrtimer on the current CPU
1035 * @timer: the timer to be added
1037 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
1038 * relative (HRTIMER_MODE_REL)
1042 * 1 when the timer was active
1045 hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1047 return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1049 EXPORT_SYMBOL_GPL(hrtimer_start);
1053 * hrtimer_try_to_cancel - try to deactivate a timer
1054 * @timer: hrtimer to stop
1057 * 0 when the timer was not active
1058 * 1 when the timer was active
1059 * -1 when the timer is currently excuting the callback function and
1062 int hrtimer_try_to_cancel(struct hrtimer *timer)
1064 struct hrtimer_clock_base *base;
1065 unsigned long flags;
1068 base = lock_hrtimer_base(timer, &flags);
1070 if (!hrtimer_callback_running(timer))
1071 ret = remove_hrtimer(timer, base);
1073 unlock_hrtimer_base(timer, &flags);
1078 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1081 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1082 * @timer: the timer to be cancelled
1085 * 0 when the timer was not active
1086 * 1 when the timer was active
1088 int hrtimer_cancel(struct hrtimer *timer)
1091 int ret = hrtimer_try_to_cancel(timer);
1098 EXPORT_SYMBOL_GPL(hrtimer_cancel);
1101 * hrtimer_get_remaining - get remaining time for the timer
1102 * @timer: the timer to read
1104 ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1106 unsigned long flags;
1109 lock_hrtimer_base(timer, &flags);
1110 rem = hrtimer_expires_remaining(timer);
1111 unlock_hrtimer_base(timer, &flags);
1115 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1117 #ifdef CONFIG_NO_HZ_COMMON
1119 * hrtimer_get_next_event - get the time until next expiry event
1121 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1124 ktime_t hrtimer_get_next_event(void)
1126 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1127 ktime_t mindelta = { .tv64 = KTIME_MAX };
1128 unsigned long flags;
1130 raw_spin_lock_irqsave(&cpu_base->lock, flags);
1132 if (!hrtimer_hres_active())
1133 mindelta = ktime_sub(__hrtimer_get_next_event(cpu_base),
1136 raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1138 if (mindelta.tv64 < 0)
1144 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1145 enum hrtimer_mode mode)
1147 struct hrtimer_cpu_base *cpu_base;
1150 memset(timer, 0, sizeof(struct hrtimer));
1152 cpu_base = raw_cpu_ptr(&hrtimer_bases);
1154 if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1155 clock_id = CLOCK_MONOTONIC;
1157 base = hrtimer_clockid_to_base(clock_id);
1158 timer->base = &cpu_base->clock_base[base];
1159 timerqueue_init(&timer->node);
1161 #ifdef CONFIG_TIMER_STATS
1162 timer->start_site = NULL;
1163 timer->start_pid = -1;
1164 memset(timer->start_comm, 0, TASK_COMM_LEN);
1169 * hrtimer_init - initialize a timer to the given clock
1170 * @timer: the timer to be initialized
1171 * @clock_id: the clock to be used
1172 * @mode: timer mode abs/rel
1174 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1175 enum hrtimer_mode mode)
1177 debug_init(timer, clock_id, mode);
1178 __hrtimer_init(timer, clock_id, mode);
1180 EXPORT_SYMBOL_GPL(hrtimer_init);
1183 * hrtimer_get_res - get the timer resolution for a clock
1184 * @which_clock: which clock to query
1185 * @tp: pointer to timespec variable to store the resolution
1187 * Store the resolution of the clock selected by @which_clock in the
1188 * variable pointed to by @tp.
1190 int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1193 tp->tv_nsec = hrtimer_resolution;
1196 EXPORT_SYMBOL_GPL(hrtimer_get_res);
1198 static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1200 struct hrtimer_clock_base *base = timer->base;
1201 struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1202 enum hrtimer_restart (*fn)(struct hrtimer *);
1205 WARN_ON(!irqs_disabled());
1207 debug_deactivate(timer);
1208 __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1209 timer_stats_account_hrtimer(timer);
1210 fn = timer->function;
1213 * Because we run timers from hardirq context, there is no chance
1214 * they get migrated to another cpu, therefore its safe to unlock
1217 raw_spin_unlock(&cpu_base->lock);
1218 trace_hrtimer_expire_entry(timer, now);
1219 restart = fn(timer);
1220 trace_hrtimer_expire_exit(timer);
1221 raw_spin_lock(&cpu_base->lock);
1224 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1225 * we do not reprogramm the event hardware. Happens either in
1226 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1228 if (restart != HRTIMER_NORESTART) {
1229 BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1230 enqueue_hrtimer(timer, base);
1233 WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1235 timer->state &= ~HRTIMER_STATE_CALLBACK;
1238 #ifdef CONFIG_HIGH_RES_TIMERS
1241 * High resolution timer interrupt
1242 * Called with interrupts disabled
1244 void hrtimer_interrupt(struct clock_event_device *dev)
1246 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1247 ktime_t expires_next, now, entry_time, delta;
1250 BUG_ON(!cpu_base->hres_active);
1251 cpu_base->nr_events++;
1252 dev->next_event.tv64 = KTIME_MAX;
1254 raw_spin_lock(&cpu_base->lock);
1255 entry_time = now = hrtimer_update_base(cpu_base);
1257 cpu_base->in_hrtirq = 1;
1259 * We set expires_next to KTIME_MAX here with cpu_base->lock
1260 * held to prevent that a timer is enqueued in our queue via
1261 * the migration code. This does not affect enqueueing of
1262 * timers which run their callback and need to be requeued on
1265 cpu_base->expires_next.tv64 = KTIME_MAX;
1267 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1268 struct hrtimer_clock_base *base;
1269 struct timerqueue_node *node;
1272 if (!(cpu_base->active_bases & (1 << i)))
1275 base = cpu_base->clock_base + i;
1276 basenow = ktime_add(now, base->offset);
1278 while ((node = timerqueue_getnext(&base->active))) {
1279 struct hrtimer *timer;
1281 timer = container_of(node, struct hrtimer, node);
1284 * The immediate goal for using the softexpires is
1285 * minimizing wakeups, not running timers at the
1286 * earliest interrupt after their soft expiration.
1287 * This allows us to avoid using a Priority Search
1288 * Tree, which can answer a stabbing querry for
1289 * overlapping intervals and instead use the simple
1290 * BST we already have.
1291 * We don't add extra wakeups by delaying timers that
1292 * are right-of a not yet expired timer, because that
1293 * timer will have to trigger a wakeup anyway.
1295 if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer))
1298 __run_hrtimer(timer, &basenow);
1301 /* Reevaluate the clock bases for the next expiry */
1302 expires_next = __hrtimer_get_next_event(cpu_base);
1304 * Store the new expiry value so the migration code can verify
1307 cpu_base->expires_next = expires_next;
1308 cpu_base->in_hrtirq = 0;
1309 raw_spin_unlock(&cpu_base->lock);
1311 /* Reprogramming necessary ? */
1312 if (expires_next.tv64 == KTIME_MAX ||
1313 !tick_program_event(expires_next, 0)) {
1314 cpu_base->hang_detected = 0;
1319 * The next timer was already expired due to:
1321 * - long lasting callbacks
1322 * - being scheduled away when running in a VM
1324 * We need to prevent that we loop forever in the hrtimer
1325 * interrupt routine. We give it 3 attempts to avoid
1326 * overreacting on some spurious event.
1328 * Acquire base lock for updating the offsets and retrieving
1331 raw_spin_lock(&cpu_base->lock);
1332 now = hrtimer_update_base(cpu_base);
1333 cpu_base->nr_retries++;
1337 * Give the system a chance to do something else than looping
1338 * here. We stored the entry time, so we know exactly how long
1339 * we spent here. We schedule the next event this amount of
1342 cpu_base->nr_hangs++;
1343 cpu_base->hang_detected = 1;
1344 raw_spin_unlock(&cpu_base->lock);
1345 delta = ktime_sub(now, entry_time);
1346 if (delta.tv64 > cpu_base->max_hang_time.tv64)
1347 cpu_base->max_hang_time = delta;
1349 * Limit it to a sensible value as we enforce a longer
1350 * delay. Give the CPU at least 100ms to catch up.
1352 if (delta.tv64 > 100 * NSEC_PER_MSEC)
1353 expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
1355 expires_next = ktime_add(now, delta);
1356 tick_program_event(expires_next, 1);
1357 printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
1358 ktime_to_ns(delta));
1362 * local version of hrtimer_peek_ahead_timers() called with interrupts
1365 static void __hrtimer_peek_ahead_timers(void)
1367 struct tick_device *td;
1369 if (!hrtimer_hres_active())
1372 td = this_cpu_ptr(&tick_cpu_device);
1373 if (td && td->evtdev)
1374 hrtimer_interrupt(td->evtdev);
1378 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1380 * hrtimer_peek_ahead_timers will peek at the timer queue of
1381 * the current cpu and check if there are any timers for which
1382 * the soft expires time has passed. If any such timers exist,
1383 * they are run immediately and then removed from the timer queue.
1386 void hrtimer_peek_ahead_timers(void)
1388 unsigned long flags;
1390 local_irq_save(flags);
1391 __hrtimer_peek_ahead_timers();
1392 local_irq_restore(flags);
1395 static void run_hrtimer_softirq(struct softirq_action *h)
1397 hrtimer_peek_ahead_timers();
1400 #else /* CONFIG_HIGH_RES_TIMERS */
1402 static inline void __hrtimer_peek_ahead_timers(void) { }
1404 #endif /* !CONFIG_HIGH_RES_TIMERS */
1407 * Called from timer softirq every jiffy, expire hrtimers:
1409 * For HRT its the fall back code to run the softirq in the timer
1410 * softirq context in case the hrtimer initialization failed or has
1411 * not been done yet.
1413 void hrtimer_run_pending(void)
1415 if (hrtimer_hres_active())
1419 * This _is_ ugly: We have to check in the softirq context,
1420 * whether we can switch to highres and / or nohz mode. The
1421 * clocksource switch happens in the timer interrupt with
1422 * xtime_lock held. Notification from there only sets the
1423 * check bit in the tick_oneshot code, otherwise we might
1424 * deadlock vs. xtime_lock.
1426 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1427 hrtimer_switch_to_hres();
1431 * Called from hardirq context every jiffy
1433 void hrtimer_run_queues(void)
1435 struct timerqueue_node *node;
1436 struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
1437 struct hrtimer_clock_base *base;
1438 int index, gettime = 1;
1440 if (hrtimer_hres_active())
1443 for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
1444 base = &cpu_base->clock_base[index];
1445 if (!timerqueue_getnext(&base->active))
1449 hrtimer_get_softirq_time(cpu_base);
1453 raw_spin_lock(&cpu_base->lock);
1455 while ((node = timerqueue_getnext(&base->active))) {
1456 struct hrtimer *timer;
1458 timer = container_of(node, struct hrtimer, node);
1459 if (base->softirq_time.tv64 <=
1460 hrtimer_get_expires_tv64(timer))
1463 __run_hrtimer(timer, &base->softirq_time);
1465 raw_spin_unlock(&cpu_base->lock);
1470 * Sleep related functions:
1472 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
1474 struct hrtimer_sleeper *t =
1475 container_of(timer, struct hrtimer_sleeper, timer);
1476 struct task_struct *task = t->task;
1480 wake_up_process(task);
1482 return HRTIMER_NORESTART;
1485 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
1487 sl->timer.function = hrtimer_wakeup;
1490 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
1492 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
1494 hrtimer_init_sleeper(t, current);
1497 set_current_state(TASK_INTERRUPTIBLE);
1498 hrtimer_start_expires(&t->timer, mode);
1499 if (!hrtimer_active(&t->timer))
1502 if (likely(t->task))
1503 freezable_schedule();
1505 hrtimer_cancel(&t->timer);
1506 mode = HRTIMER_MODE_ABS;
1508 } while (t->task && !signal_pending(current));
1510 __set_current_state(TASK_RUNNING);
1512 return t->task == NULL;
1515 static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
1517 struct timespec rmt;
1520 rem = hrtimer_expires_remaining(timer);
1523 rmt = ktime_to_timespec(rem);
1525 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
1531 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
1533 struct hrtimer_sleeper t;
1534 struct timespec __user *rmtp;
1537 hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid,
1539 hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
1541 if (do_nanosleep(&t, HRTIMER_MODE_ABS))
1544 rmtp = restart->nanosleep.rmtp;
1546 ret = update_rmtp(&t.timer, rmtp);
1551 /* The other values in restart are already filled in */
1552 ret = -ERESTART_RESTARTBLOCK;
1554 destroy_hrtimer_on_stack(&t.timer);
1558 long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
1559 const enum hrtimer_mode mode, const clockid_t clockid)
1561 struct restart_block *restart;
1562 struct hrtimer_sleeper t;
1564 unsigned long slack;
1566 slack = current->timer_slack_ns;
1567 if (dl_task(current) || rt_task(current))
1570 hrtimer_init_on_stack(&t.timer, clockid, mode);
1571 hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
1572 if (do_nanosleep(&t, mode))
1575 /* Absolute timers do not update the rmtp value and restart: */
1576 if (mode == HRTIMER_MODE_ABS) {
1577 ret = -ERESTARTNOHAND;
1582 ret = update_rmtp(&t.timer, rmtp);
1587 restart = ¤t->restart_block;
1588 restart->fn = hrtimer_nanosleep_restart;
1589 restart->nanosleep.clockid = t.timer.base->clockid;
1590 restart->nanosleep.rmtp = rmtp;
1591 restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
1593 ret = -ERESTART_RESTARTBLOCK;
1595 destroy_hrtimer_on_stack(&t.timer);
1599 SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
1600 struct timespec __user *, rmtp)
1604 if (copy_from_user(&tu, rqtp, sizeof(tu)))
1607 if (!timespec_valid(&tu))
1610 return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
1614 * Functions related to boot-time initialization:
1616 static void init_hrtimers_cpu(int cpu)
1618 struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1621 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1622 cpu_base->clock_base[i].cpu_base = cpu_base;
1623 timerqueue_init_head(&cpu_base->clock_base[i].active);
1626 cpu_base->cpu = cpu;
1627 hrtimer_init_hres(cpu_base);
1630 #ifdef CONFIG_HOTPLUG_CPU
1632 static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1633 struct hrtimer_clock_base *new_base)
1635 struct hrtimer *timer;
1636 struct timerqueue_node *node;
1638 while ((node = timerqueue_getnext(&old_base->active))) {
1639 timer = container_of(node, struct hrtimer, node);
1640 BUG_ON(hrtimer_callback_running(timer));
1641 debug_deactivate(timer);
1644 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1645 * timer could be seen as !active and just vanish away
1646 * under us on another CPU
1648 __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1649 timer->base = new_base;
1651 * Enqueue the timers on the new cpu. This does not
1652 * reprogram the event device in case the timer
1653 * expires before the earliest on this CPU, but we run
1654 * hrtimer_interrupt after we migrated everything to
1655 * sort out already expired timers and reprogram the
1658 enqueue_hrtimer(timer, new_base);
1660 /* Clear the migration state bit */
1661 timer->state &= ~HRTIMER_STATE_MIGRATE;
1665 static void migrate_hrtimers(int scpu)
1667 struct hrtimer_cpu_base *old_base, *new_base;
1670 BUG_ON(cpu_online(scpu));
1671 tick_cancel_sched_timer(scpu);
1673 local_irq_disable();
1674 old_base = &per_cpu(hrtimer_bases, scpu);
1675 new_base = this_cpu_ptr(&hrtimer_bases);
1677 * The caller is globally serialized and nobody else
1678 * takes two locks at once, deadlock is not possible.
1680 raw_spin_lock(&new_base->lock);
1681 raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1683 for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1684 migrate_hrtimer_list(&old_base->clock_base[i],
1685 &new_base->clock_base[i]);
1688 raw_spin_unlock(&old_base->lock);
1689 raw_spin_unlock(&new_base->lock);
1691 /* Check, if we got expired work to do */
1692 __hrtimer_peek_ahead_timers();
1696 #endif /* CONFIG_HOTPLUG_CPU */
1698 static int hrtimer_cpu_notify(struct notifier_block *self,
1699 unsigned long action, void *hcpu)
1701 int scpu = (long)hcpu;
1705 case CPU_UP_PREPARE:
1706 case CPU_UP_PREPARE_FROZEN:
1707 init_hrtimers_cpu(scpu);
1710 #ifdef CONFIG_HOTPLUG_CPU
1712 case CPU_DEAD_FROZEN:
1713 migrate_hrtimers(scpu);
1724 static struct notifier_block hrtimers_nb = {
1725 .notifier_call = hrtimer_cpu_notify,
1728 void __init hrtimers_init(void)
1730 hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1731 (void *)(long)smp_processor_id());
1732 register_cpu_notifier(&hrtimers_nb);
1733 #ifdef CONFIG_HIGH_RES_TIMERS
1734 open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1739 * schedule_hrtimeout_range_clock - sleep until timeout
1740 * @expires: timeout value (ktime_t)
1741 * @delta: slack in expires timeout (ktime_t)
1742 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1743 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1746 schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1747 const enum hrtimer_mode mode, int clock)
1749 struct hrtimer_sleeper t;
1752 * Optimize when a zero timeout value is given. It does not
1753 * matter whether this is an absolute or a relative time.
1755 if (expires && !expires->tv64) {
1756 __set_current_state(TASK_RUNNING);
1761 * A NULL parameter means "infinite"
1768 hrtimer_init_on_stack(&t.timer, clock, mode);
1769 hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1771 hrtimer_init_sleeper(&t, current);
1773 hrtimer_start_expires(&t.timer, mode);
1774 if (!hrtimer_active(&t.timer))
1780 hrtimer_cancel(&t.timer);
1781 destroy_hrtimer_on_stack(&t.timer);
1783 __set_current_state(TASK_RUNNING);
1785 return !t.task ? 0 : -EINTR;
1789 * schedule_hrtimeout_range - sleep until timeout
1790 * @expires: timeout value (ktime_t)
1791 * @delta: slack in expires timeout (ktime_t)
1792 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1794 * Make the current task sleep until the given expiry time has
1795 * elapsed. The routine will return immediately unless
1796 * the current task state has been set (see set_current_state()).
1798 * The @delta argument gives the kernel the freedom to schedule the
1799 * actual wakeup to a time that is both power and performance friendly.
1800 * The kernel give the normal best effort behavior for "@expires+@delta",
1801 * but may decide to fire the timer earlier, but no earlier than @expires.
1803 * You can set the task state as follows -
1805 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1806 * pass before the routine returns.
1808 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1809 * delivered to the current task.
1811 * The current task state is guaranteed to be TASK_RUNNING when this
1814 * Returns 0 when the timer has expired otherwise -EINTR
1816 int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1817 const enum hrtimer_mode mode)
1819 return schedule_hrtimeout_range_clock(expires, delta, mode,
1822 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1825 * schedule_hrtimeout - sleep until timeout
1826 * @expires: timeout value (ktime_t)
1827 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1829 * Make the current task sleep until the given expiry time has
1830 * elapsed. The routine will return immediately unless
1831 * the current task state has been set (see set_current_state()).
1833 * You can set the task state as follows -
1835 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1836 * pass before the routine returns.
1838 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1839 * delivered to the current task.
1841 * The current task state is guaranteed to be TASK_RUNNING when this
1844 * Returns 0 when the timer has expired otherwise -EINTR
1846 int __sched schedule_hrtimeout(ktime_t *expires,
1847 const enum hrtimer_mode mode)
1849 return schedule_hrtimeout_range(expires, 0, mode);
1851 EXPORT_SYMBOL_GPL(schedule_hrtimeout);