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
= 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 spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
131 if (likely(base
== timer
->base
))
133 /* The timer has migrated to another CPU: */
134 spin_unlock_irqrestore(&base
->cpu_base
->lock
, *flags
);
142 * Get the preferred target CPU for NOHZ
144 static int hrtimer_get_target(int this_cpu
, int pinned
)
147 if (!pinned
&& get_sysctl_timer_migration() && idle_cpu(this_cpu
)) {
148 int preferred_cpu
= get_nohz_load_balancer();
150 if (preferred_cpu
>= 0)
151 return preferred_cpu
;
158 * With HIGHRES=y we do not migrate the timer when it is expiring
159 * before the next event on the target cpu because we cannot reprogram
160 * the target cpu hardware and we would cause it to fire late.
162 * Called with cpu_base->lock of target cpu held.
165 hrtimer_check_target(struct hrtimer
*timer
, struct hrtimer_clock_base
*new_base
)
167 #ifdef CONFIG_HIGH_RES_TIMERS
170 if (!new_base
->cpu_base
->hres_active
)
173 expires
= ktime_sub(hrtimer_get_expires(timer
), new_base
->offset
);
174 return expires
.tv64
<= new_base
->cpu_base
->expires_next
.tv64
;
181 * Switch the timer base to the current CPU when possible.
183 static inline struct hrtimer_clock_base
*
184 switch_hrtimer_base(struct hrtimer
*timer
, struct hrtimer_clock_base
*base
,
187 struct hrtimer_clock_base
*new_base
;
188 struct hrtimer_cpu_base
*new_cpu_base
;
189 int this_cpu
= smp_processor_id();
190 int cpu
= hrtimer_get_target(this_cpu
, pinned
);
193 new_cpu_base
= &per_cpu(hrtimer_bases
, cpu
);
194 new_base
= &new_cpu_base
->clock_base
[base
->index
];
196 if (base
!= new_base
) {
198 * We are trying to move timer to new_base.
199 * However we can't change timer's base while it is running,
200 * so we keep it on the same CPU. No hassle vs. reprogramming
201 * the event source in the high resolution case. The softirq
202 * code will take care of this when the timer function has
203 * completed. There is no conflict as we hold the lock until
204 * the timer is enqueued.
206 if (unlikely(hrtimer_callback_running(timer
)))
209 /* See the comment in lock_timer_base() */
211 spin_unlock(&base
->cpu_base
->lock
);
212 spin_lock(&new_base
->cpu_base
->lock
);
214 if (cpu
!= this_cpu
&& hrtimer_check_target(timer
, new_base
)) {
216 spin_unlock(&new_base
->cpu_base
->lock
);
217 spin_lock(&base
->cpu_base
->lock
);
221 timer
->base
= new_base
;
226 #else /* CONFIG_SMP */
228 static inline struct hrtimer_clock_base
*
229 lock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
231 struct hrtimer_clock_base
*base
= timer
->base
;
233 spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
238 # define switch_hrtimer_base(t, b, p) (b)
240 #endif /* !CONFIG_SMP */
243 * Functions for the union type storage format of ktime_t which are
244 * too large for inlining:
246 #if BITS_PER_LONG < 64
247 # ifndef CONFIG_KTIME_SCALAR
249 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
251 * @nsec: the scalar nsec value to add
253 * Returns the sum of kt and nsec in ktime_t format
255 ktime_t
ktime_add_ns(const ktime_t kt
, u64 nsec
)
259 if (likely(nsec
< NSEC_PER_SEC
)) {
262 unsigned long rem
= do_div(nsec
, NSEC_PER_SEC
);
264 tmp
= ktime_set((long)nsec
, rem
);
267 return ktime_add(kt
, tmp
);
270 EXPORT_SYMBOL_GPL(ktime_add_ns
);
273 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
275 * @nsec: the scalar nsec value to subtract
277 * Returns the subtraction of @nsec from @kt in ktime_t format
279 ktime_t
ktime_sub_ns(const ktime_t kt
, u64 nsec
)
283 if (likely(nsec
< NSEC_PER_SEC
)) {
286 unsigned long rem
= do_div(nsec
, NSEC_PER_SEC
);
288 tmp
= ktime_set((long)nsec
, rem
);
291 return ktime_sub(kt
, tmp
);
294 EXPORT_SYMBOL_GPL(ktime_sub_ns
);
295 # endif /* !CONFIG_KTIME_SCALAR */
298 * Divide a ktime value by a nanosecond value
300 u64
ktime_divns(const ktime_t kt
, s64 div
)
305 dclc
= ktime_to_ns(kt
);
306 /* Make sure the divisor is less than 2^32: */
312 do_div(dclc
, (unsigned long) div
);
316 #endif /* BITS_PER_LONG >= 64 */
319 * Add two ktime values and do a safety check for overflow:
321 ktime_t
ktime_add_safe(const ktime_t lhs
, const ktime_t rhs
)
323 ktime_t res
= ktime_add(lhs
, rhs
);
326 * We use KTIME_SEC_MAX here, the maximum timeout which we can
327 * return to user space in a timespec:
329 if (res
.tv64
< 0 || res
.tv64
< lhs
.tv64
|| res
.tv64
< rhs
.tv64
)
330 res
= ktime_set(KTIME_SEC_MAX
, 0);
335 EXPORT_SYMBOL_GPL(ktime_add_safe
);
337 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
339 static struct debug_obj_descr hrtimer_debug_descr
;
342 * fixup_init is called when:
343 * - an active object is initialized
345 static int hrtimer_fixup_init(void *addr
, enum debug_obj_state state
)
347 struct hrtimer
*timer
= addr
;
350 case ODEBUG_STATE_ACTIVE
:
351 hrtimer_cancel(timer
);
352 debug_object_init(timer
, &hrtimer_debug_descr
);
360 * fixup_activate is called when:
361 * - an active object is activated
362 * - an unknown object is activated (might be a statically initialized object)
364 static int hrtimer_fixup_activate(void *addr
, enum debug_obj_state state
)
368 case ODEBUG_STATE_NOTAVAILABLE
:
372 case ODEBUG_STATE_ACTIVE
:
381 * fixup_free is called when:
382 * - an active object is freed
384 static int hrtimer_fixup_free(void *addr
, enum debug_obj_state state
)
386 struct hrtimer
*timer
= addr
;
389 case ODEBUG_STATE_ACTIVE
:
390 hrtimer_cancel(timer
);
391 debug_object_free(timer
, &hrtimer_debug_descr
);
398 static struct debug_obj_descr hrtimer_debug_descr
= {
400 .fixup_init
= hrtimer_fixup_init
,
401 .fixup_activate
= hrtimer_fixup_activate
,
402 .fixup_free
= hrtimer_fixup_free
,
405 static inline void debug_hrtimer_init(struct hrtimer
*timer
)
407 debug_object_init(timer
, &hrtimer_debug_descr
);
410 static inline void debug_hrtimer_activate(struct hrtimer
*timer
)
412 debug_object_activate(timer
, &hrtimer_debug_descr
);
415 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
)
417 debug_object_deactivate(timer
, &hrtimer_debug_descr
);
420 static inline void debug_hrtimer_free(struct hrtimer
*timer
)
422 debug_object_free(timer
, &hrtimer_debug_descr
);
425 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
426 enum hrtimer_mode mode
);
428 void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t clock_id
,
429 enum hrtimer_mode mode
)
431 debug_object_init_on_stack(timer
, &hrtimer_debug_descr
);
432 __hrtimer_init(timer
, clock_id
, mode
);
434 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack
);
436 void destroy_hrtimer_on_stack(struct hrtimer
*timer
)
438 debug_object_free(timer
, &hrtimer_debug_descr
);
442 static inline void debug_hrtimer_init(struct hrtimer
*timer
) { }
443 static inline void debug_hrtimer_activate(struct hrtimer
*timer
) { }
444 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
) { }
448 debug_init(struct hrtimer
*timer
, clockid_t clockid
,
449 enum hrtimer_mode mode
)
451 debug_hrtimer_init(timer
);
452 trace_hrtimer_init(timer
, clockid
, mode
);
455 static inline void debug_activate(struct hrtimer
*timer
)
457 debug_hrtimer_activate(timer
);
458 trace_hrtimer_start(timer
);
461 static inline void debug_deactivate(struct hrtimer
*timer
)
463 debug_hrtimer_deactivate(timer
);
464 trace_hrtimer_cancel(timer
);
467 /* High resolution timer related functions */
468 #ifdef CONFIG_HIGH_RES_TIMERS
471 * High resolution timer enabled ?
473 static int hrtimer_hres_enabled __read_mostly
= 1;
476 * Enable / Disable high resolution mode
478 static int __init
setup_hrtimer_hres(char *str
)
480 if (!strcmp(str
, "off"))
481 hrtimer_hres_enabled
= 0;
482 else if (!strcmp(str
, "on"))
483 hrtimer_hres_enabled
= 1;
489 __setup("highres=", setup_hrtimer_hres
);
492 * hrtimer_high_res_enabled - query, if the highres mode is enabled
494 static inline int hrtimer_is_hres_enabled(void)
496 return hrtimer_hres_enabled
;
500 * Is the high resolution mode active ?
502 static inline int hrtimer_hres_active(void)
504 return __get_cpu_var(hrtimer_bases
).hres_active
;
508 * Reprogram the event source with checking both queues for the
510 * Called with interrupts disabled and base->lock held
512 static void hrtimer_force_reprogram(struct hrtimer_cpu_base
*cpu_base
)
515 struct hrtimer_clock_base
*base
= cpu_base
->clock_base
;
518 cpu_base
->expires_next
.tv64
= KTIME_MAX
;
520 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++, base
++) {
521 struct hrtimer
*timer
;
525 timer
= rb_entry(base
->first
, 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
< cpu_base
->expires_next
.tv64
)
535 cpu_base
->expires_next
= expires
;
538 if (cpu_base
->expires_next
.tv64
!= KTIME_MAX
)
539 tick_program_event(cpu_base
->expires_next
, 1);
543 * Shared reprogramming for clock_realtime and clock_monotonic
545 * When a timer is enqueued and expires earlier than the already enqueued
546 * timers, we have to check, whether it expires earlier than the timer for
547 * which the clock event device was armed.
549 * Called with interrupts disabled and base->cpu_base.lock held
551 static int hrtimer_reprogram(struct hrtimer
*timer
,
552 struct hrtimer_clock_base
*base
)
554 ktime_t
*expires_next
= &__get_cpu_var(hrtimer_bases
).expires_next
;
555 ktime_t expires
= ktime_sub(hrtimer_get_expires(timer
), base
->offset
);
558 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer
) < 0);
561 * When the callback is running, we do not reprogram the clock event
562 * device. The timer callback is either running on a different CPU or
563 * the callback is executed in the hrtimer_interrupt context. The
564 * reprogramming is handled either by the softirq, which called the
565 * callback or at the end of the hrtimer_interrupt.
567 if (hrtimer_callback_running(timer
))
571 * CLOCK_REALTIME timer might be requested with an absolute
572 * expiry time which is less than base->offset. Nothing wrong
573 * about that, just avoid to call into the tick code, which
574 * has now objections against negative expiry values.
576 if (expires
.tv64
< 0)
579 if (expires
.tv64
>= expires_next
->tv64
)
583 * Clockevents returns -ETIME, when the event was in the past.
585 res
= tick_program_event(expires
, 0);
586 if (!IS_ERR_VALUE(res
))
587 *expires_next
= expires
;
593 * Retrigger next event is called after clock was set
595 * Called with interrupts disabled via on_each_cpu()
597 static void retrigger_next_event(void *arg
)
599 struct hrtimer_cpu_base
*base
;
600 struct timespec realtime_offset
;
603 if (!hrtimer_hres_active())
607 seq
= read_seqbegin(&xtime_lock
);
608 set_normalized_timespec(&realtime_offset
,
609 -wall_to_monotonic
.tv_sec
,
610 -wall_to_monotonic
.tv_nsec
);
611 } while (read_seqretry(&xtime_lock
, seq
));
613 base
= &__get_cpu_var(hrtimer_bases
);
615 /* Adjust CLOCK_REALTIME offset */
616 spin_lock(&base
->lock
);
617 base
->clock_base
[CLOCK_REALTIME
].offset
=
618 timespec_to_ktime(realtime_offset
);
620 hrtimer_force_reprogram(base
);
621 spin_unlock(&base
->lock
);
625 * Clock realtime was set
627 * Change the offset of the realtime clock vs. the monotonic
630 * We might have to reprogram the high resolution timer interrupt. On
631 * SMP we call the architecture specific code to retrigger _all_ high
632 * resolution timer interrupts. On UP we just disable interrupts and
633 * call the high resolution interrupt code.
635 void clock_was_set(void)
637 /* Retrigger the CPU local events everywhere */
638 on_each_cpu(retrigger_next_event
, NULL
, 1);
642 * During resume we might have to reprogram the high resolution timer
643 * interrupt (on the local CPU):
645 void hres_timers_resume(void)
647 WARN_ONCE(!irqs_disabled(),
648 KERN_INFO
"hres_timers_resume() called with IRQs enabled!");
650 retrigger_next_event(NULL
);
654 * Initialize the high resolution related parts of cpu_base
656 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
)
658 base
->expires_next
.tv64
= KTIME_MAX
;
659 base
->hres_active
= 0;
663 * Initialize the high resolution related parts of a hrtimer
665 static inline void hrtimer_init_timer_hres(struct hrtimer
*timer
)
671 * When High resolution timers are active, try to reprogram. Note, that in case
672 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
673 * check happens. The timer gets enqueued into the rbtree. The reprogramming
674 * and expiry check is done in the hrtimer_interrupt or in the softirq.
676 static inline int hrtimer_enqueue_reprogram(struct hrtimer
*timer
,
677 struct hrtimer_clock_base
*base
,
680 if (base
->cpu_base
->hres_active
&& hrtimer_reprogram(timer
, base
)) {
682 spin_unlock(&base
->cpu_base
->lock
);
683 raise_softirq_irqoff(HRTIMER_SOFTIRQ
);
684 spin_lock(&base
->cpu_base
->lock
);
686 __raise_softirq_irqoff(HRTIMER_SOFTIRQ
);
695 * Switch to high resolution mode
697 static int hrtimer_switch_to_hres(void)
699 int cpu
= smp_processor_id();
700 struct hrtimer_cpu_base
*base
= &per_cpu(hrtimer_bases
, cpu
);
703 if (base
->hres_active
)
706 local_irq_save(flags
);
708 if (tick_init_highres()) {
709 local_irq_restore(flags
);
710 printk(KERN_WARNING
"Could not switch to high resolution "
711 "mode on CPU %d\n", cpu
);
714 base
->hres_active
= 1;
715 base
->clock_base
[CLOCK_REALTIME
].resolution
= KTIME_HIGH_RES
;
716 base
->clock_base
[CLOCK_MONOTONIC
].resolution
= KTIME_HIGH_RES
;
718 tick_setup_sched_timer();
720 /* "Retrigger" the interrupt to get things going */
721 retrigger_next_event(NULL
);
722 local_irq_restore(flags
);
728 static inline int hrtimer_hres_active(void) { return 0; }
729 static inline int hrtimer_is_hres_enabled(void) { return 0; }
730 static inline int hrtimer_switch_to_hres(void) { return 0; }
731 static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base
*base
) { }
732 static inline int hrtimer_enqueue_reprogram(struct hrtimer
*timer
,
733 struct hrtimer_clock_base
*base
,
738 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
) { }
739 static inline void hrtimer_init_timer_hres(struct hrtimer
*timer
) { }
741 #endif /* CONFIG_HIGH_RES_TIMERS */
743 #ifdef CONFIG_TIMER_STATS
744 void __timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
, void *addr
)
746 if (timer
->start_site
)
749 timer
->start_site
= addr
;
750 memcpy(timer
->start_comm
, current
->comm
, TASK_COMM_LEN
);
751 timer
->start_pid
= current
->pid
;
756 * Counterpart to lock_hrtimer_base above:
759 void unlock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
761 spin_unlock_irqrestore(&timer
->base
->cpu_base
->lock
, *flags
);
765 * hrtimer_forward - forward the timer expiry
766 * @timer: hrtimer to forward
767 * @now: forward past this time
768 * @interval: the interval to forward
770 * Forward the timer expiry so it will expire in the future.
771 * Returns the number of overruns.
773 u64
hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
)
778 delta
= ktime_sub(now
, hrtimer_get_expires(timer
));
783 if (interval
.tv64
< timer
->base
->resolution
.tv64
)
784 interval
.tv64
= timer
->base
->resolution
.tv64
;
786 if (unlikely(delta
.tv64
>= interval
.tv64
)) {
787 s64 incr
= ktime_to_ns(interval
);
789 orun
= ktime_divns(delta
, incr
);
790 hrtimer_add_expires_ns(timer
, incr
* orun
);
791 if (hrtimer_get_expires_tv64(timer
) > now
.tv64
)
794 * This (and the ktime_add() below) is the
795 * correction for exact:
799 hrtimer_add_expires(timer
, interval
);
803 EXPORT_SYMBOL_GPL(hrtimer_forward
);
806 * enqueue_hrtimer - internal function to (re)start a timer
808 * The timer is inserted in expiry order. Insertion into the
809 * red black tree is O(log(n)). Must hold the base lock.
811 * Returns 1 when the new timer is the leftmost timer in the tree.
813 static int enqueue_hrtimer(struct hrtimer
*timer
,
814 struct hrtimer_clock_base
*base
)
816 struct rb_node
**link
= &base
->active
.rb_node
;
817 struct rb_node
*parent
= NULL
;
818 struct hrtimer
*entry
;
821 debug_activate(timer
);
824 * Find the right place in the rbtree:
828 entry
= rb_entry(parent
, struct hrtimer
, node
);
830 * We dont care about collisions. Nodes with
831 * the same expiry time stay together.
833 if (hrtimer_get_expires_tv64(timer
) <
834 hrtimer_get_expires_tv64(entry
)) {
835 link
= &(*link
)->rb_left
;
837 link
= &(*link
)->rb_right
;
843 * Insert the timer to the rbtree and check whether it
844 * replaces the first pending timer
847 base
->first
= &timer
->node
;
849 rb_link_node(&timer
->node
, parent
, link
);
850 rb_insert_color(&timer
->node
, &base
->active
);
852 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
853 * state of a possibly running callback.
855 timer
->state
|= HRTIMER_STATE_ENQUEUED
;
861 * __remove_hrtimer - internal function to remove a timer
863 * Caller must hold the base lock.
865 * High resolution timer mode reprograms the clock event device when the
866 * timer is the one which expires next. The caller can disable this by setting
867 * reprogram to zero. This is useful, when the context does a reprogramming
868 * anyway (e.g. timer interrupt)
870 static void __remove_hrtimer(struct hrtimer
*timer
,
871 struct hrtimer_clock_base
*base
,
872 unsigned long newstate
, int reprogram
)
874 if (timer
->state
& HRTIMER_STATE_ENQUEUED
) {
876 * Remove the timer from the rbtree and replace the
877 * first entry pointer if necessary.
879 if (base
->first
== &timer
->node
) {
880 base
->first
= rb_next(&timer
->node
);
881 /* Reprogram the clock event device. if enabled */
882 if (reprogram
&& hrtimer_hres_active())
883 hrtimer_force_reprogram(base
->cpu_base
);
885 rb_erase(&timer
->node
, &base
->active
);
887 timer
->state
= newstate
;
891 * remove hrtimer, called with base lock held
894 remove_hrtimer(struct hrtimer
*timer
, struct hrtimer_clock_base
*base
)
896 if (hrtimer_is_queued(timer
)) {
900 * Remove the timer and force reprogramming when high
901 * resolution mode is active and the timer is on the current
902 * CPU. If we remove a timer on another CPU, reprogramming is
903 * skipped. The interrupt event on this CPU is fired and
904 * reprogramming happens in the interrupt handler. This is a
905 * rare case and less expensive than a smp call.
907 debug_deactivate(timer
);
908 timer_stats_hrtimer_clear_start_info(timer
);
909 reprogram
= base
->cpu_base
== &__get_cpu_var(hrtimer_bases
);
910 __remove_hrtimer(timer
, base
, HRTIMER_STATE_INACTIVE
,
917 int __hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
918 unsigned long delta_ns
, const enum hrtimer_mode mode
,
921 struct hrtimer_clock_base
*base
, *new_base
;
925 base
= lock_hrtimer_base(timer
, &flags
);
927 /* Remove an active timer from the queue: */
928 ret
= remove_hrtimer(timer
, base
);
930 /* Switch the timer base, if necessary: */
931 new_base
= switch_hrtimer_base(timer
, base
, mode
& HRTIMER_MODE_PINNED
);
933 if (mode
& HRTIMER_MODE_REL
) {
934 tim
= ktime_add_safe(tim
, new_base
->get_time());
936 * CONFIG_TIME_LOW_RES is a temporary way for architectures
937 * to signal that they simply return xtime in
938 * do_gettimeoffset(). In this case we want to round up by
939 * resolution when starting a relative timer, to avoid short
940 * timeouts. This will go away with the GTOD framework.
942 #ifdef CONFIG_TIME_LOW_RES
943 tim
= ktime_add_safe(tim
, base
->resolution
);
947 hrtimer_set_expires_range_ns(timer
, tim
, delta_ns
);
949 timer_stats_hrtimer_set_start_info(timer
);
951 leftmost
= enqueue_hrtimer(timer
, new_base
);
954 * Only allow reprogramming if the new base is on this CPU.
955 * (it might still be on another CPU if the timer was pending)
957 * XXX send_remote_softirq() ?
959 if (leftmost
&& new_base
->cpu_base
== &__get_cpu_var(hrtimer_bases
))
960 hrtimer_enqueue_reprogram(timer
, new_base
, wakeup
);
962 unlock_hrtimer_base(timer
, &flags
);
968 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
969 * @timer: the timer to be added
971 * @delta_ns: "slack" range for the timer
972 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
976 * 1 when the timer was active
978 int hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
979 unsigned long delta_ns
, const enum hrtimer_mode mode
)
981 return __hrtimer_start_range_ns(timer
, tim
, delta_ns
, mode
, 1);
983 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns
);
986 * hrtimer_start - (re)start an hrtimer on the current CPU
987 * @timer: the timer to be added
989 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
993 * 1 when the timer was active
996 hrtimer_start(struct hrtimer
*timer
, ktime_t tim
, const enum hrtimer_mode mode
)
998 return __hrtimer_start_range_ns(timer
, tim
, 0, mode
, 1);
1000 EXPORT_SYMBOL_GPL(hrtimer_start
);
1004 * hrtimer_try_to_cancel - try to deactivate a timer
1005 * @timer: hrtimer to stop
1008 * 0 when the timer was not active
1009 * 1 when the timer was active
1010 * -1 when the timer is currently excuting the callback function and
1013 int hrtimer_try_to_cancel(struct hrtimer
*timer
)
1015 struct hrtimer_clock_base
*base
;
1016 unsigned long flags
;
1019 base
= lock_hrtimer_base(timer
, &flags
);
1021 if (!hrtimer_callback_running(timer
))
1022 ret
= remove_hrtimer(timer
, base
);
1024 unlock_hrtimer_base(timer
, &flags
);
1029 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel
);
1032 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1033 * @timer: the timer to be cancelled
1036 * 0 when the timer was not active
1037 * 1 when the timer was active
1039 int hrtimer_cancel(struct hrtimer
*timer
)
1042 int ret
= hrtimer_try_to_cancel(timer
);
1049 EXPORT_SYMBOL_GPL(hrtimer_cancel
);
1052 * hrtimer_get_remaining - get remaining time for the timer
1053 * @timer: the timer to read
1055 ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
)
1057 struct hrtimer_clock_base
*base
;
1058 unsigned long flags
;
1061 base
= lock_hrtimer_base(timer
, &flags
);
1062 rem
= hrtimer_expires_remaining(timer
);
1063 unlock_hrtimer_base(timer
, &flags
);
1067 EXPORT_SYMBOL_GPL(hrtimer_get_remaining
);
1071 * hrtimer_get_next_event - get the time until next expiry event
1073 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1076 ktime_t
hrtimer_get_next_event(void)
1078 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1079 struct hrtimer_clock_base
*base
= cpu_base
->clock_base
;
1080 ktime_t delta
, mindelta
= { .tv64
= KTIME_MAX
};
1081 unsigned long flags
;
1084 spin_lock_irqsave(&cpu_base
->lock
, flags
);
1086 if (!hrtimer_hres_active()) {
1087 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++, base
++) {
1088 struct hrtimer
*timer
;
1093 timer
= rb_entry(base
->first
, struct hrtimer
, node
);
1094 delta
.tv64
= hrtimer_get_expires_tv64(timer
);
1095 delta
= ktime_sub(delta
, base
->get_time());
1096 if (delta
.tv64
< mindelta
.tv64
)
1097 mindelta
.tv64
= delta
.tv64
;
1101 spin_unlock_irqrestore(&cpu_base
->lock
, flags
);
1103 if (mindelta
.tv64
< 0)
1109 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1110 enum hrtimer_mode mode
)
1112 struct hrtimer_cpu_base
*cpu_base
;
1114 memset(timer
, 0, sizeof(struct hrtimer
));
1116 cpu_base
= &__raw_get_cpu_var(hrtimer_bases
);
1118 if (clock_id
== CLOCK_REALTIME
&& mode
!= HRTIMER_MODE_ABS
)
1119 clock_id
= CLOCK_MONOTONIC
;
1121 timer
->base
= &cpu_base
->clock_base
[clock_id
];
1122 hrtimer_init_timer_hres(timer
);
1124 #ifdef CONFIG_TIMER_STATS
1125 timer
->start_site
= NULL
;
1126 timer
->start_pid
= -1;
1127 memset(timer
->start_comm
, 0, TASK_COMM_LEN
);
1132 * hrtimer_init - initialize a timer to the given clock
1133 * @timer: the timer to be initialized
1134 * @clock_id: the clock to be used
1135 * @mode: timer mode abs/rel
1137 void hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1138 enum hrtimer_mode mode
)
1140 debug_init(timer
, clock_id
, mode
);
1141 __hrtimer_init(timer
, clock_id
, mode
);
1143 EXPORT_SYMBOL_GPL(hrtimer_init
);
1146 * hrtimer_get_res - get the timer resolution for a clock
1147 * @which_clock: which clock to query
1148 * @tp: pointer to timespec variable to store the resolution
1150 * Store the resolution of the clock selected by @which_clock in the
1151 * variable pointed to by @tp.
1153 int hrtimer_get_res(const clockid_t which_clock
, struct timespec
*tp
)
1155 struct hrtimer_cpu_base
*cpu_base
;
1157 cpu_base
= &__raw_get_cpu_var(hrtimer_bases
);
1158 *tp
= ktime_to_timespec(cpu_base
->clock_base
[which_clock
].resolution
);
1162 EXPORT_SYMBOL_GPL(hrtimer_get_res
);
1164 static void __run_hrtimer(struct hrtimer
*timer
, ktime_t
*now
)
1166 struct hrtimer_clock_base
*base
= timer
->base
;
1167 struct hrtimer_cpu_base
*cpu_base
= base
->cpu_base
;
1168 enum hrtimer_restart (*fn
)(struct hrtimer
*);
1171 WARN_ON(!irqs_disabled());
1173 debug_deactivate(timer
);
1174 __remove_hrtimer(timer
, base
, HRTIMER_STATE_CALLBACK
, 0);
1175 timer_stats_account_hrtimer(timer
);
1176 fn
= timer
->function
;
1179 * Because we run timers from hardirq context, there is no chance
1180 * they get migrated to another cpu, therefore its safe to unlock
1183 spin_unlock(&cpu_base
->lock
);
1184 trace_hrtimer_expire_entry(timer
, now
);
1185 restart
= fn(timer
);
1186 trace_hrtimer_expire_exit(timer
);
1187 spin_lock(&cpu_base
->lock
);
1190 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1191 * we do not reprogramm the event hardware. Happens either in
1192 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1194 if (restart
!= HRTIMER_NORESTART
) {
1195 BUG_ON(timer
->state
!= HRTIMER_STATE_CALLBACK
);
1196 enqueue_hrtimer(timer
, base
);
1198 timer
->state
&= ~HRTIMER_STATE_CALLBACK
;
1201 #ifdef CONFIG_HIGH_RES_TIMERS
1203 static int force_clock_reprogram
;
1206 * After 5 iteration's attempts, we consider that hrtimer_interrupt()
1207 * is hanging, which could happen with something that slows the interrupt
1208 * such as the tracing. Then we force the clock reprogramming for each future
1209 * hrtimer interrupts to avoid infinite loops and use the min_delta_ns
1210 * threshold that we will overwrite.
1211 * The next tick event will be scheduled to 3 times we currently spend on
1212 * hrtimer_interrupt(). This gives a good compromise, the cpus will spend
1213 * 1/4 of their time to process the hrtimer interrupts. This is enough to
1214 * let it running without serious starvation.
1218 hrtimer_interrupt_hanging(struct clock_event_device
*dev
,
1221 force_clock_reprogram
= 1;
1222 dev
->min_delta_ns
= (unsigned long)try_time
.tv64
* 3;
1223 printk(KERN_WARNING
"hrtimer: interrupt too slow, "
1224 "forcing clock min delta to %lu ns\n", dev
->min_delta_ns
);
1227 * High resolution timer interrupt
1228 * Called with interrupts disabled
1230 void hrtimer_interrupt(struct clock_event_device
*dev
)
1232 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1233 struct hrtimer_clock_base
*base
;
1234 ktime_t expires_next
, now
;
1238 BUG_ON(!cpu_base
->hres_active
);
1239 cpu_base
->nr_events
++;
1240 dev
->next_event
.tv64
= KTIME_MAX
;
1243 /* 5 retries is enough to notice a hang */
1244 if (!(++nr_retries
% 5))
1245 hrtimer_interrupt_hanging(dev
, ktime_sub(ktime_get(), now
));
1249 expires_next
.tv64
= KTIME_MAX
;
1251 spin_lock(&cpu_base
->lock
);
1253 * We set expires_next to KTIME_MAX here with cpu_base->lock
1254 * held to prevent that a timer is enqueued in our queue via
1255 * the migration code. This does not affect enqueueing of
1256 * timers which run their callback and need to be requeued on
1259 cpu_base
->expires_next
.tv64
= KTIME_MAX
;
1261 base
= cpu_base
->clock_base
;
1263 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1265 struct rb_node
*node
;
1267 basenow
= ktime_add(now
, base
->offset
);
1269 while ((node
= base
->first
)) {
1270 struct hrtimer
*timer
;
1272 timer
= rb_entry(node
, struct hrtimer
, node
);
1275 * The immediate goal for using the softexpires is
1276 * minimizing wakeups, not running timers at the
1277 * earliest interrupt after their soft expiration.
1278 * This allows us to avoid using a Priority Search
1279 * Tree, which can answer a stabbing querry for
1280 * overlapping intervals and instead use the simple
1281 * BST we already have.
1282 * We don't add extra wakeups by delaying timers that
1283 * are right-of a not yet expired timer, because that
1284 * timer will have to trigger a wakeup anyway.
1287 if (basenow
.tv64
< hrtimer_get_softexpires_tv64(timer
)) {
1290 expires
= ktime_sub(hrtimer_get_expires(timer
),
1292 if (expires
.tv64
< expires_next
.tv64
)
1293 expires_next
= expires
;
1297 __run_hrtimer(timer
, &basenow
);
1303 * Store the new expiry value so the migration code can verify
1306 cpu_base
->expires_next
= expires_next
;
1307 spin_unlock(&cpu_base
->lock
);
1309 /* Reprogramming necessary ? */
1310 if (expires_next
.tv64
!= KTIME_MAX
) {
1311 if (tick_program_event(expires_next
, force_clock_reprogram
))
1317 * local version of hrtimer_peek_ahead_timers() called with interrupts
1320 static void __hrtimer_peek_ahead_timers(void)
1322 struct tick_device
*td
;
1324 if (!hrtimer_hres_active())
1327 td
= &__get_cpu_var(tick_cpu_device
);
1328 if (td
&& td
->evtdev
)
1329 hrtimer_interrupt(td
->evtdev
);
1333 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1335 * hrtimer_peek_ahead_timers will peek at the timer queue of
1336 * the current cpu and check if there are any timers for which
1337 * the soft expires time has passed. If any such timers exist,
1338 * they are run immediately and then removed from the timer queue.
1341 void hrtimer_peek_ahead_timers(void)
1343 unsigned long flags
;
1345 local_irq_save(flags
);
1346 __hrtimer_peek_ahead_timers();
1347 local_irq_restore(flags
);
1350 static void run_hrtimer_softirq(struct softirq_action
*h
)
1352 hrtimer_peek_ahead_timers();
1355 #else /* CONFIG_HIGH_RES_TIMERS */
1357 static inline void __hrtimer_peek_ahead_timers(void) { }
1359 #endif /* !CONFIG_HIGH_RES_TIMERS */
1362 * Called from timer softirq every jiffy, expire hrtimers:
1364 * For HRT its the fall back code to run the softirq in the timer
1365 * softirq context in case the hrtimer initialization failed or has
1366 * not been done yet.
1368 void hrtimer_run_pending(void)
1370 if (hrtimer_hres_active())
1374 * This _is_ ugly: We have to check in the softirq context,
1375 * whether we can switch to highres and / or nohz mode. The
1376 * clocksource switch happens in the timer interrupt with
1377 * xtime_lock held. Notification from there only sets the
1378 * check bit in the tick_oneshot code, otherwise we might
1379 * deadlock vs. xtime_lock.
1381 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1382 hrtimer_switch_to_hres();
1386 * Called from hardirq context every jiffy
1388 void hrtimer_run_queues(void)
1390 struct rb_node
*node
;
1391 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1392 struct hrtimer_clock_base
*base
;
1393 int index
, gettime
= 1;
1395 if (hrtimer_hres_active())
1398 for (index
= 0; index
< HRTIMER_MAX_CLOCK_BASES
; index
++) {
1399 base
= &cpu_base
->clock_base
[index
];
1405 hrtimer_get_softirq_time(cpu_base
);
1409 spin_lock(&cpu_base
->lock
);
1411 while ((node
= base
->first
)) {
1412 struct hrtimer
*timer
;
1414 timer
= rb_entry(node
, struct hrtimer
, node
);
1415 if (base
->softirq_time
.tv64
<=
1416 hrtimer_get_expires_tv64(timer
))
1419 __run_hrtimer(timer
, &base
->softirq_time
);
1421 spin_unlock(&cpu_base
->lock
);
1426 * Sleep related functions:
1428 static enum hrtimer_restart
hrtimer_wakeup(struct hrtimer
*timer
)
1430 struct hrtimer_sleeper
*t
=
1431 container_of(timer
, struct hrtimer_sleeper
, timer
);
1432 struct task_struct
*task
= t
->task
;
1436 wake_up_process(task
);
1438 return HRTIMER_NORESTART
;
1441 void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
, struct task_struct
*task
)
1443 sl
->timer
.function
= hrtimer_wakeup
;
1446 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper
);
1448 static int __sched
do_nanosleep(struct hrtimer_sleeper
*t
, enum hrtimer_mode mode
)
1450 hrtimer_init_sleeper(t
, current
);
1453 set_current_state(TASK_INTERRUPTIBLE
);
1454 hrtimer_start_expires(&t
->timer
, mode
);
1455 if (!hrtimer_active(&t
->timer
))
1458 if (likely(t
->task
))
1461 hrtimer_cancel(&t
->timer
);
1462 mode
= HRTIMER_MODE_ABS
;
1464 } while (t
->task
&& !signal_pending(current
));
1466 __set_current_state(TASK_RUNNING
);
1468 return t
->task
== NULL
;
1471 static int update_rmtp(struct hrtimer
*timer
, struct timespec __user
*rmtp
)
1473 struct timespec rmt
;
1476 rem
= hrtimer_expires_remaining(timer
);
1479 rmt
= ktime_to_timespec(rem
);
1481 if (copy_to_user(rmtp
, &rmt
, sizeof(*rmtp
)))
1487 long __sched
hrtimer_nanosleep_restart(struct restart_block
*restart
)
1489 struct hrtimer_sleeper t
;
1490 struct timespec __user
*rmtp
;
1493 hrtimer_init_on_stack(&t
.timer
, restart
->nanosleep
.index
,
1495 hrtimer_set_expires_tv64(&t
.timer
, restart
->nanosleep
.expires
);
1497 if (do_nanosleep(&t
, HRTIMER_MODE_ABS
))
1500 rmtp
= restart
->nanosleep
.rmtp
;
1502 ret
= update_rmtp(&t
.timer
, rmtp
);
1507 /* The other values in restart are already filled in */
1508 ret
= -ERESTART_RESTARTBLOCK
;
1510 destroy_hrtimer_on_stack(&t
.timer
);
1514 long hrtimer_nanosleep(struct timespec
*rqtp
, struct timespec __user
*rmtp
,
1515 const enum hrtimer_mode mode
, const clockid_t clockid
)
1517 struct restart_block
*restart
;
1518 struct hrtimer_sleeper t
;
1520 unsigned long slack
;
1522 slack
= current
->timer_slack_ns
;
1523 if (rt_task(current
))
1526 hrtimer_init_on_stack(&t
.timer
, clockid
, mode
);
1527 hrtimer_set_expires_range_ns(&t
.timer
, timespec_to_ktime(*rqtp
), slack
);
1528 if (do_nanosleep(&t
, mode
))
1531 /* Absolute timers do not update the rmtp value and restart: */
1532 if (mode
== HRTIMER_MODE_ABS
) {
1533 ret
= -ERESTARTNOHAND
;
1538 ret
= update_rmtp(&t
.timer
, rmtp
);
1543 restart
= ¤t_thread_info()->restart_block
;
1544 restart
->fn
= hrtimer_nanosleep_restart
;
1545 restart
->nanosleep
.index
= t
.timer
.base
->index
;
1546 restart
->nanosleep
.rmtp
= rmtp
;
1547 restart
->nanosleep
.expires
= hrtimer_get_expires_tv64(&t
.timer
);
1549 ret
= -ERESTART_RESTARTBLOCK
;
1551 destroy_hrtimer_on_stack(&t
.timer
);
1555 SYSCALL_DEFINE2(nanosleep
, struct timespec __user
*, rqtp
,
1556 struct timespec __user
*, rmtp
)
1560 if (copy_from_user(&tu
, rqtp
, sizeof(tu
)))
1563 if (!timespec_valid(&tu
))
1566 return hrtimer_nanosleep(&tu
, rmtp
, HRTIMER_MODE_REL
, CLOCK_MONOTONIC
);
1570 * Functions related to boot-time initialization:
1572 static void __cpuinit
init_hrtimers_cpu(int cpu
)
1574 struct hrtimer_cpu_base
*cpu_base
= &per_cpu(hrtimer_bases
, cpu
);
1577 spin_lock_init(&cpu_base
->lock
);
1579 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++)
1580 cpu_base
->clock_base
[i
].cpu_base
= cpu_base
;
1582 hrtimer_init_hres(cpu_base
);
1585 #ifdef CONFIG_HOTPLUG_CPU
1587 static void migrate_hrtimer_list(struct hrtimer_clock_base
*old_base
,
1588 struct hrtimer_clock_base
*new_base
)
1590 struct hrtimer
*timer
;
1591 struct rb_node
*node
;
1593 while ((node
= rb_first(&old_base
->active
))) {
1594 timer
= rb_entry(node
, struct hrtimer
, node
);
1595 BUG_ON(hrtimer_callback_running(timer
));
1596 debug_deactivate(timer
);
1599 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1600 * timer could be seen as !active and just vanish away
1601 * under us on another CPU
1603 __remove_hrtimer(timer
, old_base
, HRTIMER_STATE_MIGRATE
, 0);
1604 timer
->base
= new_base
;
1606 * Enqueue the timers on the new cpu. This does not
1607 * reprogram the event device in case the timer
1608 * expires before the earliest on this CPU, but we run
1609 * hrtimer_interrupt after we migrated everything to
1610 * sort out already expired timers and reprogram the
1613 enqueue_hrtimer(timer
, new_base
);
1615 /* Clear the migration state bit */
1616 timer
->state
&= ~HRTIMER_STATE_MIGRATE
;
1620 static void migrate_hrtimers(int scpu
)
1622 struct hrtimer_cpu_base
*old_base
, *new_base
;
1625 BUG_ON(cpu_online(scpu
));
1626 tick_cancel_sched_timer(scpu
);
1628 local_irq_disable();
1629 old_base
= &per_cpu(hrtimer_bases
, scpu
);
1630 new_base
= &__get_cpu_var(hrtimer_bases
);
1632 * The caller is globally serialized and nobody else
1633 * takes two locks at once, deadlock is not possible.
1635 spin_lock(&new_base
->lock
);
1636 spin_lock_nested(&old_base
->lock
, SINGLE_DEPTH_NESTING
);
1638 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1639 migrate_hrtimer_list(&old_base
->clock_base
[i
],
1640 &new_base
->clock_base
[i
]);
1643 spin_unlock(&old_base
->lock
);
1644 spin_unlock(&new_base
->lock
);
1646 /* Check, if we got expired work to do */
1647 __hrtimer_peek_ahead_timers();
1651 #endif /* CONFIG_HOTPLUG_CPU */
1653 static int __cpuinit
hrtimer_cpu_notify(struct notifier_block
*self
,
1654 unsigned long action
, void *hcpu
)
1656 int scpu
= (long)hcpu
;
1660 case CPU_UP_PREPARE
:
1661 case CPU_UP_PREPARE_FROZEN
:
1662 init_hrtimers_cpu(scpu
);
1665 #ifdef CONFIG_HOTPLUG_CPU
1667 case CPU_DYING_FROZEN
:
1668 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING
, &scpu
);
1671 case CPU_DEAD_FROZEN
:
1673 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD
, &scpu
);
1674 migrate_hrtimers(scpu
);
1686 static struct notifier_block __cpuinitdata 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 - 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
1706 * Make the current task sleep until the given expiry time has
1707 * elapsed. The routine will return immediately unless
1708 * the current task state has been set (see set_current_state()).
1710 * The @delta argument gives the kernel the freedom to schedule the
1711 * actual wakeup to a time that is both power and performance friendly.
1712 * The kernel give the normal best effort behavior for "@expires+@delta",
1713 * but may decide to fire the timer earlier, but no earlier than @expires.
1715 * You can set the task state as follows -
1717 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1718 * pass before the routine returns.
1720 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1721 * delivered to the current task.
1723 * The current task state is guaranteed to be TASK_RUNNING when this
1726 * Returns 0 when the timer has expired otherwise -EINTR
1728 int __sched
schedule_hrtimeout_range(ktime_t
*expires
, unsigned long delta
,
1729 const enum hrtimer_mode mode
)
1731 struct hrtimer_sleeper t
;
1734 * Optimize when a zero timeout value is given. It does not
1735 * matter whether this is an absolute or a relative time.
1737 if (expires
&& !expires
->tv64
) {
1738 __set_current_state(TASK_RUNNING
);
1743 * A NULL parameter means "inifinte"
1747 __set_current_state(TASK_RUNNING
);
1751 hrtimer_init_on_stack(&t
.timer
, CLOCK_MONOTONIC
, mode
);
1752 hrtimer_set_expires_range_ns(&t
.timer
, *expires
, delta
);
1754 hrtimer_init_sleeper(&t
, current
);
1756 hrtimer_start_expires(&t
.timer
, mode
);
1757 if (!hrtimer_active(&t
.timer
))
1763 hrtimer_cancel(&t
.timer
);
1764 destroy_hrtimer_on_stack(&t
.timer
);
1766 __set_current_state(TASK_RUNNING
);
1768 return !t
.task
? 0 : -EINTR
;
1770 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range
);
1773 * schedule_hrtimeout - sleep until timeout
1774 * @expires: timeout value (ktime_t)
1775 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1777 * Make the current task sleep until the given expiry time has
1778 * elapsed. The routine will return immediately unless
1779 * the current task state has been set (see set_current_state()).
1781 * You can set the task state as follows -
1783 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1784 * pass before the routine returns.
1786 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1787 * delivered to the current task.
1789 * The current task state is guaranteed to be TASK_RUNNING when this
1792 * Returns 0 when the timer has expired otherwise -EINTR
1794 int __sched
schedule_hrtimeout(ktime_t
*expires
,
1795 const enum hrtimer_mode mode
)
1797 return schedule_hrtimeout_range(expires
, 0, mode
);
1799 EXPORT_SYMBOL_GPL(schedule_hrtimeout
);