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/irq.h>
36 #include <linux/module.h>
37 #include <linux/percpu.h>
38 #include <linux/hrtimer.h>
39 #include <linux/notifier.h>
40 #include <linux/syscalls.h>
41 #include <linux/kallsyms.h>
42 #include <linux/interrupt.h>
43 #include <linux/tick.h>
44 #include <linux/seq_file.h>
45 #include <linux/err.h>
46 #include <linux/debugobjects.h>
48 #include <asm/uaccess.h>
51 * ktime_get - get the monotonic time in ktime_t format
53 * returns the time in ktime_t format
55 ktime_t
ktime_get(void)
61 return timespec_to_ktime(now
);
63 EXPORT_SYMBOL_GPL(ktime_get
);
66 * ktime_get_real - get the real (wall-) time in ktime_t format
68 * returns the time in ktime_t format
70 ktime_t
ktime_get_real(void)
76 return timespec_to_ktime(now
);
79 EXPORT_SYMBOL_GPL(ktime_get_real
);
84 * Note: If we want to add new timer bases, we have to skip the two
85 * clock ids captured by the cpu-timers. We do this by holding empty
86 * entries rather than doing math adjustment of the clock ids.
87 * This ensures that we capture erroneous accesses to these clock ids
88 * rather than moving them into the range of valid clock id's.
90 DEFINE_PER_CPU(struct hrtimer_cpu_base
, hrtimer_bases
) =
96 .index
= CLOCK_REALTIME
,
97 .get_time
= &ktime_get_real
,
98 .resolution
= KTIME_LOW_RES
,
101 .index
= CLOCK_MONOTONIC
,
102 .get_time
= &ktime_get
,
103 .resolution
= KTIME_LOW_RES
,
109 * ktime_get_ts - get the monotonic clock in timespec format
110 * @ts: pointer to timespec variable
112 * The function calculates the monotonic clock from the realtime
113 * clock and the wall_to_monotonic offset and stores the result
114 * in normalized timespec format in the variable pointed to by @ts.
116 void ktime_get_ts(struct timespec
*ts
)
118 struct timespec tomono
;
122 seq
= read_seqbegin(&xtime_lock
);
124 tomono
= wall_to_monotonic
;
126 } while (read_seqretry(&xtime_lock
, seq
));
128 set_normalized_timespec(ts
, ts
->tv_sec
+ tomono
.tv_sec
,
129 ts
->tv_nsec
+ tomono
.tv_nsec
);
131 EXPORT_SYMBOL_GPL(ktime_get_ts
);
134 * Get the coarse grained time at the softirq based on xtime and
137 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base
*base
)
139 ktime_t xtim
, tomono
;
140 struct timespec xts
, tom
;
144 seq
= read_seqbegin(&xtime_lock
);
145 xts
= current_kernel_time();
146 tom
= wall_to_monotonic
;
147 } while (read_seqretry(&xtime_lock
, seq
));
149 xtim
= timespec_to_ktime(xts
);
150 tomono
= timespec_to_ktime(tom
);
151 base
->clock_base
[CLOCK_REALTIME
].softirq_time
= xtim
;
152 base
->clock_base
[CLOCK_MONOTONIC
].softirq_time
=
153 ktime_add(xtim
, tomono
);
157 * Functions and macros which are different for UP/SMP systems are kept in a
163 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
164 * means that all timers which are tied to this base via timer->base are
165 * locked, and the base itself is locked too.
167 * So __run_timers/migrate_timers can safely modify all timers which could
168 * be found on the lists/queues.
170 * When the timer's base is locked, and the timer removed from list, it is
171 * possible to set timer->base = NULL and drop the lock: the timer remains
175 struct hrtimer_clock_base
*lock_hrtimer_base(const struct hrtimer
*timer
,
176 unsigned long *flags
)
178 struct hrtimer_clock_base
*base
;
182 if (likely(base
!= NULL
)) {
183 spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
184 if (likely(base
== timer
->base
))
186 /* The timer has migrated to another CPU: */
187 spin_unlock_irqrestore(&base
->cpu_base
->lock
, *flags
);
194 * Switch the timer base to the current CPU when possible.
196 static inline struct hrtimer_clock_base
*
197 switch_hrtimer_base(struct hrtimer
*timer
, struct hrtimer_clock_base
*base
)
199 struct hrtimer_clock_base
*new_base
;
200 struct hrtimer_cpu_base
*new_cpu_base
;
202 new_cpu_base
= &__get_cpu_var(hrtimer_bases
);
203 new_base
= &new_cpu_base
->clock_base
[base
->index
];
205 if (base
!= new_base
) {
207 * We are trying to schedule the timer on the local CPU.
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 spin_unlock(&base
->cpu_base
->lock
);
221 spin_lock(&new_base
->cpu_base
->lock
);
222 timer
->base
= new_base
;
227 #else /* CONFIG_SMP */
229 static inline struct hrtimer_clock_base
*
230 lock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
232 struct hrtimer_clock_base
*base
= timer
->base
;
234 spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
239 # define switch_hrtimer_base(t, b) (b)
241 #endif /* !CONFIG_SMP */
244 * Functions for the union type storage format of ktime_t which are
245 * too large for inlining:
247 #if BITS_PER_LONG < 64
248 # ifndef CONFIG_KTIME_SCALAR
250 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
252 * @nsec: the scalar nsec value to add
254 * Returns the sum of kt and nsec in ktime_t format
256 ktime_t
ktime_add_ns(const ktime_t kt
, u64 nsec
)
260 if (likely(nsec
< NSEC_PER_SEC
)) {
263 unsigned long rem
= do_div(nsec
, NSEC_PER_SEC
);
265 tmp
= ktime_set((long)nsec
, rem
);
268 return ktime_add(kt
, tmp
);
271 EXPORT_SYMBOL_GPL(ktime_add_ns
);
274 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
276 * @nsec: the scalar nsec value to subtract
278 * Returns the subtraction of @nsec from @kt in ktime_t format
280 ktime_t
ktime_sub_ns(const ktime_t kt
, u64 nsec
)
284 if (likely(nsec
< NSEC_PER_SEC
)) {
287 unsigned long rem
= do_div(nsec
, NSEC_PER_SEC
);
289 tmp
= ktime_set((long)nsec
, rem
);
292 return ktime_sub(kt
, tmp
);
295 EXPORT_SYMBOL_GPL(ktime_sub_ns
);
296 # endif /* !CONFIG_KTIME_SCALAR */
299 * Divide a ktime value by a nanosecond value
301 u64
ktime_divns(const ktime_t kt
, s64 div
)
306 dclc
= ktime_to_ns(kt
);
307 /* Make sure the divisor is less than 2^32: */
313 do_div(dclc
, (unsigned long) div
);
317 #endif /* BITS_PER_LONG >= 64 */
320 * Add two ktime values and do a safety check for overflow:
322 ktime_t
ktime_add_safe(const ktime_t lhs
, const ktime_t rhs
)
324 ktime_t res
= ktime_add(lhs
, rhs
);
327 * We use KTIME_SEC_MAX here, the maximum timeout which we can
328 * return to user space in a timespec:
330 if (res
.tv64
< 0 || res
.tv64
< lhs
.tv64
|| res
.tv64
< rhs
.tv64
)
331 res
= ktime_set(KTIME_SEC_MAX
, 0);
336 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
338 static struct debug_obj_descr hrtimer_debug_descr
;
341 * fixup_init is called when:
342 * - an active object is initialized
344 static int hrtimer_fixup_init(void *addr
, enum debug_obj_state state
)
346 struct hrtimer
*timer
= addr
;
349 case ODEBUG_STATE_ACTIVE
:
350 hrtimer_cancel(timer
);
351 debug_object_init(timer
, &hrtimer_debug_descr
);
359 * fixup_activate is called when:
360 * - an active object is activated
361 * - an unknown object is activated (might be a statically initialized object)
363 static int hrtimer_fixup_activate(void *addr
, enum debug_obj_state state
)
367 case ODEBUG_STATE_NOTAVAILABLE
:
371 case ODEBUG_STATE_ACTIVE
:
380 * fixup_free is called when:
381 * - an active object is freed
383 static int hrtimer_fixup_free(void *addr
, enum debug_obj_state state
)
385 struct hrtimer
*timer
= addr
;
388 case ODEBUG_STATE_ACTIVE
:
389 hrtimer_cancel(timer
);
390 debug_object_free(timer
, &hrtimer_debug_descr
);
397 static struct debug_obj_descr hrtimer_debug_descr
= {
399 .fixup_init
= hrtimer_fixup_init
,
400 .fixup_activate
= hrtimer_fixup_activate
,
401 .fixup_free
= hrtimer_fixup_free
,
404 static inline void debug_hrtimer_init(struct hrtimer
*timer
)
406 debug_object_init(timer
, &hrtimer_debug_descr
);
409 static inline void debug_hrtimer_activate(struct hrtimer
*timer
)
411 debug_object_activate(timer
, &hrtimer_debug_descr
);
414 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
)
416 debug_object_deactivate(timer
, &hrtimer_debug_descr
);
419 static inline void debug_hrtimer_free(struct hrtimer
*timer
)
421 debug_object_free(timer
, &hrtimer_debug_descr
);
424 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
425 enum hrtimer_mode mode
);
427 void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t clock_id
,
428 enum hrtimer_mode mode
)
430 debug_object_init_on_stack(timer
, &hrtimer_debug_descr
);
431 __hrtimer_init(timer
, clock_id
, mode
);
434 void destroy_hrtimer_on_stack(struct hrtimer
*timer
)
436 debug_object_free(timer
, &hrtimer_debug_descr
);
440 static inline void debug_hrtimer_init(struct hrtimer
*timer
) { }
441 static inline void debug_hrtimer_activate(struct hrtimer
*timer
) { }
442 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
) { }
446 * Check, whether the timer is on the callback pending list
448 static inline int hrtimer_cb_pending(const struct hrtimer
*timer
)
450 return timer
->state
& HRTIMER_STATE_PENDING
;
454 * Remove a timer from the callback pending list
456 static inline void hrtimer_remove_cb_pending(struct hrtimer
*timer
)
458 list_del_init(&timer
->cb_entry
);
461 /* High resolution timer related functions */
462 #ifdef CONFIG_HIGH_RES_TIMERS
465 * High resolution timer enabled ?
467 static int hrtimer_hres_enabled __read_mostly
= 1;
470 * Enable / Disable high resolution mode
472 static int __init
setup_hrtimer_hres(char *str
)
474 if (!strcmp(str
, "off"))
475 hrtimer_hres_enabled
= 0;
476 else if (!strcmp(str
, "on"))
477 hrtimer_hres_enabled
= 1;
483 __setup("highres=", setup_hrtimer_hres
);
486 * hrtimer_high_res_enabled - query, if the highres mode is enabled
488 static inline int hrtimer_is_hres_enabled(void)
490 return hrtimer_hres_enabled
;
494 * Is the high resolution mode active ?
496 static inline int hrtimer_hres_active(void)
498 return __get_cpu_var(hrtimer_bases
).hres_active
;
502 * Reprogram the event source with checking both queues for the
504 * Called with interrupts disabled and base->lock held
506 static void hrtimer_force_reprogram(struct hrtimer_cpu_base
*cpu_base
)
509 struct hrtimer_clock_base
*base
= cpu_base
->clock_base
;
512 cpu_base
->expires_next
.tv64
= KTIME_MAX
;
514 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++, base
++) {
515 struct hrtimer
*timer
;
519 timer
= rb_entry(base
->first
, struct hrtimer
, node
);
520 expires
= ktime_sub(timer
->expires
, base
->offset
);
521 if (expires
.tv64
< cpu_base
->expires_next
.tv64
)
522 cpu_base
->expires_next
= expires
;
525 if (cpu_base
->expires_next
.tv64
!= KTIME_MAX
)
526 tick_program_event(cpu_base
->expires_next
, 1);
530 * Shared reprogramming for clock_realtime and clock_monotonic
532 * When a timer is enqueued and expires earlier than the already enqueued
533 * timers, we have to check, whether it expires earlier than the timer for
534 * which the clock event device was armed.
536 * Called with interrupts disabled and base->cpu_base.lock held
538 static int hrtimer_reprogram(struct hrtimer
*timer
,
539 struct hrtimer_clock_base
*base
)
541 ktime_t
*expires_next
= &__get_cpu_var(hrtimer_bases
).expires_next
;
542 ktime_t expires
= ktime_sub(timer
->expires
, base
->offset
);
545 WARN_ON_ONCE(timer
->expires
.tv64
< 0);
548 * When the callback is running, we do not reprogram the clock event
549 * device. The timer callback is either running on a different CPU or
550 * the callback is executed in the hrtimer_interrupt context. The
551 * reprogramming is handled either by the softirq, which called the
552 * callback or at the end of the hrtimer_interrupt.
554 if (hrtimer_callback_running(timer
))
558 * CLOCK_REALTIME timer might be requested with an absolute
559 * expiry time which is less than base->offset. Nothing wrong
560 * about that, just avoid to call into the tick code, which
561 * has now objections against negative expiry values.
563 if (expires
.tv64
< 0)
566 if (expires
.tv64
>= expires_next
->tv64
)
570 * Clockevents returns -ETIME, when the event was in the past.
572 res
= tick_program_event(expires
, 0);
573 if (!IS_ERR_VALUE(res
))
574 *expires_next
= expires
;
580 * Retrigger next event is called after clock was set
582 * Called with interrupts disabled via on_each_cpu()
584 static void retrigger_next_event(void *arg
)
586 struct hrtimer_cpu_base
*base
;
587 struct timespec realtime_offset
;
590 if (!hrtimer_hres_active())
594 seq
= read_seqbegin(&xtime_lock
);
595 set_normalized_timespec(&realtime_offset
,
596 -wall_to_monotonic
.tv_sec
,
597 -wall_to_monotonic
.tv_nsec
);
598 } while (read_seqretry(&xtime_lock
, seq
));
600 base
= &__get_cpu_var(hrtimer_bases
);
602 /* Adjust CLOCK_REALTIME offset */
603 spin_lock(&base
->lock
);
604 base
->clock_base
[CLOCK_REALTIME
].offset
=
605 timespec_to_ktime(realtime_offset
);
607 hrtimer_force_reprogram(base
);
608 spin_unlock(&base
->lock
);
612 * Clock realtime was set
614 * Change the offset of the realtime clock vs. the monotonic
617 * We might have to reprogram the high resolution timer interrupt. On
618 * SMP we call the architecture specific code to retrigger _all_ high
619 * resolution timer interrupts. On UP we just disable interrupts and
620 * call the high resolution interrupt code.
622 void clock_was_set(void)
624 /* Retrigger the CPU local events everywhere */
625 on_each_cpu(retrigger_next_event
, NULL
, 1);
629 * During resume we might have to reprogram the high resolution timer
630 * interrupt (on the local CPU):
632 void hres_timers_resume(void)
634 /* Retrigger the CPU local events: */
635 retrigger_next_event(NULL
);
639 * Initialize the high resolution related parts of cpu_base
641 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
)
643 base
->expires_next
.tv64
= KTIME_MAX
;
644 base
->hres_active
= 0;
648 * Initialize the high resolution related parts of a hrtimer
650 static inline void hrtimer_init_timer_hres(struct hrtimer
*timer
)
655 * When High resolution timers are active, try to reprogram. Note, that in case
656 * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
657 * check happens. The timer gets enqueued into the rbtree. The reprogramming
658 * and expiry check is done in the hrtimer_interrupt or in the softirq.
660 static inline int hrtimer_enqueue_reprogram(struct hrtimer
*timer
,
661 struct hrtimer_clock_base
*base
)
663 if (base
->cpu_base
->hres_active
&& hrtimer_reprogram(timer
, base
)) {
665 /* Timer is expired, act upon the callback mode */
666 switch(timer
->cb_mode
) {
667 case HRTIMER_CB_IRQSAFE_NO_RESTART
:
668 debug_hrtimer_deactivate(timer
);
670 * We can call the callback from here. No restart
671 * happens, so no danger of recursion
673 BUG_ON(timer
->function(timer
) != HRTIMER_NORESTART
);
675 case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
:
677 * This is solely for the sched tick emulation with
678 * dynamic tick support to ensure that we do not
679 * restart the tick right on the edge and end up with
680 * the tick timer in the softirq ! The calling site
681 * takes care of this.
683 debug_hrtimer_deactivate(timer
);
685 case HRTIMER_CB_IRQSAFE
:
686 case HRTIMER_CB_SOFTIRQ
:
688 * Move everything else into the softirq pending list !
690 list_add_tail(&timer
->cb_entry
,
691 &base
->cpu_base
->cb_pending
);
692 timer
->state
= HRTIMER_STATE_PENDING
;
702 * Switch to high resolution mode
704 static int hrtimer_switch_to_hres(void)
706 int cpu
= smp_processor_id();
707 struct hrtimer_cpu_base
*base
= &per_cpu(hrtimer_bases
, cpu
);
710 if (base
->hres_active
)
713 local_irq_save(flags
);
715 if (tick_init_highres()) {
716 local_irq_restore(flags
);
717 printk(KERN_WARNING
"Could not switch to high resolution "
718 "mode on CPU %d\n", cpu
);
721 base
->hres_active
= 1;
722 base
->clock_base
[CLOCK_REALTIME
].resolution
= KTIME_HIGH_RES
;
723 base
->clock_base
[CLOCK_MONOTONIC
].resolution
= KTIME_HIGH_RES
;
725 tick_setup_sched_timer();
727 /* "Retrigger" the interrupt to get things going */
728 retrigger_next_event(NULL
);
729 local_irq_restore(flags
);
730 printk(KERN_DEBUG
"Switched to high resolution mode on CPU %d\n",
735 static inline void hrtimer_raise_softirq(void)
737 raise_softirq(HRTIMER_SOFTIRQ
);
742 static inline int hrtimer_hres_active(void) { return 0; }
743 static inline int hrtimer_is_hres_enabled(void) { return 0; }
744 static inline int hrtimer_switch_to_hres(void) { return 0; }
745 static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base
*base
) { }
746 static inline int hrtimer_enqueue_reprogram(struct hrtimer
*timer
,
747 struct hrtimer_clock_base
*base
)
751 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
) { }
752 static inline void hrtimer_init_timer_hres(struct hrtimer
*timer
) { }
753 static inline int hrtimer_reprogram(struct hrtimer
*timer
,
754 struct hrtimer_clock_base
*base
)
758 static inline void hrtimer_raise_softirq(void) { }
760 #endif /* CONFIG_HIGH_RES_TIMERS */
762 #ifdef CONFIG_TIMER_STATS
763 void __timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
, void *addr
)
765 if (timer
->start_site
)
768 timer
->start_site
= addr
;
769 memcpy(timer
->start_comm
, current
->comm
, TASK_COMM_LEN
);
770 timer
->start_pid
= current
->pid
;
775 * Counterpart to lock_hrtimer_base above:
778 void unlock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
780 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 u64
hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
)
797 delta
= ktime_sub(now
, timer
->expires
);
802 if (interval
.tv64
< timer
->base
->resolution
.tv64
)
803 interval
.tv64
= timer
->base
->resolution
.tv64
;
805 if (unlikely(delta
.tv64
>= interval
.tv64
)) {
806 s64 incr
= ktime_to_ns(interval
);
808 orun
= ktime_divns(delta
, incr
);
809 timer
->expires
= ktime_add_ns(timer
->expires
, incr
* orun
);
810 if (timer
->expires
.tv64
> now
.tv64
)
813 * This (and the ktime_add() below) is the
814 * correction for exact:
818 timer
->expires
= ktime_add_safe(timer
->expires
, interval
);
822 EXPORT_SYMBOL_GPL(hrtimer_forward
);
825 * enqueue_hrtimer - internal function to (re)start a timer
827 * The timer is inserted in expiry order. Insertion into the
828 * red black tree is O(log(n)). Must hold the base lock.
830 static void enqueue_hrtimer(struct hrtimer
*timer
,
831 struct hrtimer_clock_base
*base
, int reprogram
)
833 struct rb_node
**link
= &base
->active
.rb_node
;
834 struct rb_node
*parent
= NULL
;
835 struct hrtimer
*entry
;
838 debug_hrtimer_activate(timer
);
841 * Find the right place in the rbtree:
845 entry
= rb_entry(parent
, struct hrtimer
, node
);
847 * We dont care about collisions. Nodes with
848 * the same expiry time stay together.
850 if (timer
->expires
.tv64
< entry
->expires
.tv64
) {
851 link
= &(*link
)->rb_left
;
853 link
= &(*link
)->rb_right
;
859 * Insert the timer to the rbtree and check whether it
860 * replaces the first pending timer
864 * Reprogram the clock event device. When the timer is already
865 * expired hrtimer_enqueue_reprogram has either called the
866 * callback or added it to the pending list and raised the
869 * This is a NOP for !HIGHRES
871 if (reprogram
&& hrtimer_enqueue_reprogram(timer
, base
))
874 base
->first
= &timer
->node
;
877 rb_link_node(&timer
->node
, parent
, link
);
878 rb_insert_color(&timer
->node
, &base
->active
);
880 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
881 * state of a possibly running callback.
883 timer
->state
|= HRTIMER_STATE_ENQUEUED
;
887 * __remove_hrtimer - internal function to remove a timer
889 * Caller must hold the base lock.
891 * High resolution timer mode reprograms the clock event device when the
892 * timer is the one which expires next. The caller can disable this by setting
893 * reprogram to zero. This is useful, when the context does a reprogramming
894 * anyway (e.g. timer interrupt)
896 static void __remove_hrtimer(struct hrtimer
*timer
,
897 struct hrtimer_clock_base
*base
,
898 unsigned long newstate
, int reprogram
)
900 /* High res. callback list. NOP for !HIGHRES */
901 if (hrtimer_cb_pending(timer
))
902 hrtimer_remove_cb_pending(timer
);
905 * Remove the timer from the rbtree and replace the
906 * first entry pointer if necessary.
908 if (base
->first
== &timer
->node
) {
909 base
->first
= rb_next(&timer
->node
);
910 /* Reprogram the clock event device. if enabled */
911 if (reprogram
&& hrtimer_hres_active())
912 hrtimer_force_reprogram(base
->cpu_base
);
914 rb_erase(&timer
->node
, &base
->active
);
916 timer
->state
= newstate
;
920 * remove hrtimer, called with base lock held
923 remove_hrtimer(struct hrtimer
*timer
, struct hrtimer_clock_base
*base
)
925 if (hrtimer_is_queued(timer
)) {
929 * Remove the timer and force reprogramming when high
930 * resolution mode is active and the timer is on the current
931 * CPU. If we remove a timer on another CPU, reprogramming is
932 * skipped. The interrupt event on this CPU is fired and
933 * reprogramming happens in the interrupt handler. This is a
934 * rare case and less expensive than a smp call.
936 debug_hrtimer_deactivate(timer
);
937 timer_stats_hrtimer_clear_start_info(timer
);
938 reprogram
= base
->cpu_base
== &__get_cpu_var(hrtimer_bases
);
939 __remove_hrtimer(timer
, base
, HRTIMER_STATE_INACTIVE
,
947 * hrtimer_start - (re)start an relative timer on the current CPU
948 * @timer: the timer to be added
950 * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
954 * 1 when the timer was active
957 hrtimer_start(struct hrtimer
*timer
, ktime_t tim
, const enum hrtimer_mode mode
)
959 struct hrtimer_clock_base
*base
, *new_base
;
963 base
= lock_hrtimer_base(timer
, &flags
);
965 /* Remove an active timer from the queue: */
966 ret
= remove_hrtimer(timer
, base
);
968 /* Switch the timer base, if necessary: */
969 new_base
= switch_hrtimer_base(timer
, base
);
971 if (mode
== HRTIMER_MODE_REL
) {
972 tim
= ktime_add_safe(tim
, new_base
->get_time());
974 * CONFIG_TIME_LOW_RES is a temporary way for architectures
975 * to signal that they simply return xtime in
976 * do_gettimeoffset(). In this case we want to round up by
977 * resolution when starting a relative timer, to avoid short
978 * timeouts. This will go away with the GTOD framework.
980 #ifdef CONFIG_TIME_LOW_RES
981 tim
= ktime_add_safe(tim
, base
->resolution
);
985 timer
->expires
= tim
;
987 timer_stats_hrtimer_set_start_info(timer
);
990 * Only allow reprogramming if the new base is on this CPU.
991 * (it might still be on another CPU if the timer was pending)
993 enqueue_hrtimer(timer
, new_base
,
994 new_base
->cpu_base
== &__get_cpu_var(hrtimer_bases
));
997 * The timer may be expired and moved to the cb_pending
998 * list. We can not raise the softirq with base lock held due
999 * to a possible deadlock with runqueue lock.
1001 raise
= timer
->state
== HRTIMER_STATE_PENDING
;
1004 * We use preempt_disable to prevent this task from migrating after
1005 * setting up the softirq and raising it. Otherwise, if me migrate
1006 * we will raise the softirq on the wrong CPU.
1010 unlock_hrtimer_base(timer
, &flags
);
1013 hrtimer_raise_softirq();
1018 EXPORT_SYMBOL_GPL(hrtimer_start
);
1021 * hrtimer_try_to_cancel - try to deactivate a timer
1022 * @timer: hrtimer to stop
1025 * 0 when the timer was not active
1026 * 1 when the timer was active
1027 * -1 when the timer is currently excuting the callback function and
1030 int hrtimer_try_to_cancel(struct hrtimer
*timer
)
1032 struct hrtimer_clock_base
*base
;
1033 unsigned long flags
;
1036 base
= lock_hrtimer_base(timer
, &flags
);
1038 if (!hrtimer_callback_running(timer
))
1039 ret
= remove_hrtimer(timer
, base
);
1041 unlock_hrtimer_base(timer
, &flags
);
1046 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel
);
1049 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1050 * @timer: the timer to be cancelled
1053 * 0 when the timer was not active
1054 * 1 when the timer was active
1056 int hrtimer_cancel(struct hrtimer
*timer
)
1059 int ret
= hrtimer_try_to_cancel(timer
);
1066 EXPORT_SYMBOL_GPL(hrtimer_cancel
);
1069 * hrtimer_get_remaining - get remaining time for the timer
1070 * @timer: the timer to read
1072 ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
)
1074 struct hrtimer_clock_base
*base
;
1075 unsigned long flags
;
1078 base
= lock_hrtimer_base(timer
, &flags
);
1079 rem
= ktime_sub(timer
->expires
, base
->get_time());
1080 unlock_hrtimer_base(timer
, &flags
);
1084 EXPORT_SYMBOL_GPL(hrtimer_get_remaining
);
1088 * hrtimer_get_next_event - get the time until next expiry event
1090 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1093 ktime_t
hrtimer_get_next_event(void)
1095 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1096 struct hrtimer_clock_base
*base
= cpu_base
->clock_base
;
1097 ktime_t delta
, mindelta
= { .tv64
= KTIME_MAX
};
1098 unsigned long flags
;
1101 spin_lock_irqsave(&cpu_base
->lock
, flags
);
1103 if (!hrtimer_hres_active()) {
1104 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++, base
++) {
1105 struct hrtimer
*timer
;
1110 timer
= rb_entry(base
->first
, struct hrtimer
, node
);
1111 delta
.tv64
= timer
->expires
.tv64
;
1112 delta
= ktime_sub(delta
, base
->get_time());
1113 if (delta
.tv64
< mindelta
.tv64
)
1114 mindelta
.tv64
= delta
.tv64
;
1118 spin_unlock_irqrestore(&cpu_base
->lock
, flags
);
1120 if (mindelta
.tv64
< 0)
1126 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1127 enum hrtimer_mode mode
)
1129 struct hrtimer_cpu_base
*cpu_base
;
1131 memset(timer
, 0, sizeof(struct hrtimer
));
1133 cpu_base
= &__raw_get_cpu_var(hrtimer_bases
);
1135 if (clock_id
== CLOCK_REALTIME
&& mode
!= HRTIMER_MODE_ABS
)
1136 clock_id
= CLOCK_MONOTONIC
;
1138 timer
->base
= &cpu_base
->clock_base
[clock_id
];
1139 INIT_LIST_HEAD(&timer
->cb_entry
);
1140 hrtimer_init_timer_hres(timer
);
1142 #ifdef CONFIG_TIMER_STATS
1143 timer
->start_site
= NULL
;
1144 timer
->start_pid
= -1;
1145 memset(timer
->start_comm
, 0, TASK_COMM_LEN
);
1150 * hrtimer_init - initialize a timer to the given clock
1151 * @timer: the timer to be initialized
1152 * @clock_id: the clock to be used
1153 * @mode: timer mode abs/rel
1155 void hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1156 enum hrtimer_mode mode
)
1158 debug_hrtimer_init(timer
);
1159 __hrtimer_init(timer
, clock_id
, mode
);
1161 EXPORT_SYMBOL_GPL(hrtimer_init
);
1164 * hrtimer_get_res - get the timer resolution for a clock
1165 * @which_clock: which clock to query
1166 * @tp: pointer to timespec variable to store the resolution
1168 * Store the resolution of the clock selected by @which_clock in the
1169 * variable pointed to by @tp.
1171 int hrtimer_get_res(const clockid_t which_clock
, struct timespec
*tp
)
1173 struct hrtimer_cpu_base
*cpu_base
;
1175 cpu_base
= &__raw_get_cpu_var(hrtimer_bases
);
1176 *tp
= ktime_to_timespec(cpu_base
->clock_base
[which_clock
].resolution
);
1180 EXPORT_SYMBOL_GPL(hrtimer_get_res
);
1182 static void run_hrtimer_pending(struct hrtimer_cpu_base
*cpu_base
)
1184 spin_lock_irq(&cpu_base
->lock
);
1186 while (!list_empty(&cpu_base
->cb_pending
)) {
1187 enum hrtimer_restart (*fn
)(struct hrtimer
*);
1188 struct hrtimer
*timer
;
1191 timer
= list_entry(cpu_base
->cb_pending
.next
,
1192 struct hrtimer
, cb_entry
);
1194 debug_hrtimer_deactivate(timer
);
1195 timer_stats_account_hrtimer(timer
);
1197 fn
= timer
->function
;
1198 __remove_hrtimer(timer
, timer
->base
, HRTIMER_STATE_CALLBACK
, 0);
1199 spin_unlock_irq(&cpu_base
->lock
);
1201 restart
= fn(timer
);
1203 spin_lock_irq(&cpu_base
->lock
);
1205 timer
->state
&= ~HRTIMER_STATE_CALLBACK
;
1206 if (restart
== HRTIMER_RESTART
) {
1207 BUG_ON(hrtimer_active(timer
));
1209 * Enqueue the timer, allow reprogramming of the event
1212 enqueue_hrtimer(timer
, timer
->base
, 1);
1213 } else if (hrtimer_active(timer
)) {
1215 * If the timer was rearmed on another CPU, reprogram
1218 struct hrtimer_clock_base
*base
= timer
->base
;
1220 if (base
->first
== &timer
->node
&&
1221 hrtimer_reprogram(timer
, base
)) {
1223 * Timer is expired. Thus move it from tree to
1224 * pending list again.
1226 __remove_hrtimer(timer
, base
,
1227 HRTIMER_STATE_PENDING
, 0);
1228 list_add_tail(&timer
->cb_entry
,
1229 &base
->cpu_base
->cb_pending
);
1233 spin_unlock_irq(&cpu_base
->lock
);
1236 static void __run_hrtimer(struct hrtimer
*timer
)
1238 struct hrtimer_clock_base
*base
= timer
->base
;
1239 struct hrtimer_cpu_base
*cpu_base
= base
->cpu_base
;
1240 enum hrtimer_restart (*fn
)(struct hrtimer
*);
1243 debug_hrtimer_deactivate(timer
);
1244 __remove_hrtimer(timer
, base
, HRTIMER_STATE_CALLBACK
, 0);
1245 timer_stats_account_hrtimer(timer
);
1247 fn
= timer
->function
;
1248 if (timer
->cb_mode
== HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
) {
1250 * Used for scheduler timers, avoid lock inversion with
1251 * rq->lock and tasklist_lock.
1253 * These timers are required to deal with enqueue expiry
1254 * themselves and are not allowed to migrate.
1256 spin_unlock(&cpu_base
->lock
);
1257 restart
= fn(timer
);
1258 spin_lock(&cpu_base
->lock
);
1260 restart
= fn(timer
);
1263 * Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid
1264 * reprogramming of the event hardware. This happens at the end of this
1267 if (restart
!= HRTIMER_NORESTART
) {
1268 BUG_ON(timer
->state
!= HRTIMER_STATE_CALLBACK
);
1269 enqueue_hrtimer(timer
, base
, 0);
1271 timer
->state
&= ~HRTIMER_STATE_CALLBACK
;
1274 #ifdef CONFIG_HIGH_RES_TIMERS
1277 * High resolution timer interrupt
1278 * Called with interrupts disabled
1280 void hrtimer_interrupt(struct clock_event_device
*dev
)
1282 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1283 struct hrtimer_clock_base
*base
;
1284 ktime_t expires_next
, now
;
1287 BUG_ON(!cpu_base
->hres_active
);
1288 cpu_base
->nr_events
++;
1289 dev
->next_event
.tv64
= KTIME_MAX
;
1294 expires_next
.tv64
= KTIME_MAX
;
1296 base
= cpu_base
->clock_base
;
1298 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1300 struct rb_node
*node
;
1302 spin_lock(&cpu_base
->lock
);
1304 basenow
= ktime_add(now
, base
->offset
);
1306 while ((node
= base
->first
)) {
1307 struct hrtimer
*timer
;
1309 timer
= rb_entry(node
, struct hrtimer
, node
);
1311 if (basenow
.tv64
< timer
->expires
.tv64
) {
1314 expires
= ktime_sub(timer
->expires
,
1316 if (expires
.tv64
< expires_next
.tv64
)
1317 expires_next
= expires
;
1321 /* Move softirq callbacks to the pending list */
1322 if (timer
->cb_mode
== HRTIMER_CB_SOFTIRQ
) {
1323 __remove_hrtimer(timer
, base
,
1324 HRTIMER_STATE_PENDING
, 0);
1325 list_add_tail(&timer
->cb_entry
,
1326 &base
->cpu_base
->cb_pending
);
1331 __run_hrtimer(timer
);
1333 spin_unlock(&cpu_base
->lock
);
1337 cpu_base
->expires_next
= expires_next
;
1339 /* Reprogramming necessary ? */
1340 if (expires_next
.tv64
!= KTIME_MAX
) {
1341 if (tick_program_event(expires_next
, 0))
1345 /* Raise softirq ? */
1347 raise_softirq(HRTIMER_SOFTIRQ
);
1350 static void run_hrtimer_softirq(struct softirq_action
*h
)
1352 run_hrtimer_pending(&__get_cpu_var(hrtimer_bases
));
1355 #endif /* CONFIG_HIGH_RES_TIMERS */
1358 * Called from timer softirq every jiffy, expire hrtimers:
1360 * For HRT its the fall back code to run the softirq in the timer
1361 * softirq context in case the hrtimer initialization failed or has
1362 * not been done yet.
1364 void hrtimer_run_pending(void)
1366 struct hrtimer_cpu_base
*cpu_base
= &__get_cpu_var(hrtimer_bases
);
1368 if (hrtimer_hres_active())
1372 * This _is_ ugly: We have to check in the softirq context,
1373 * whether we can switch to highres and / or nohz mode. The
1374 * clocksource switch happens in the timer interrupt with
1375 * xtime_lock held. Notification from there only sets the
1376 * check bit in the tick_oneshot code, otherwise we might
1377 * deadlock vs. xtime_lock.
1379 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1380 hrtimer_switch_to_hres();
1382 run_hrtimer_pending(cpu_base
);
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
];
1404 if (base
->get_softirq_time
)
1405 base
->softirq_time
= base
->get_softirq_time();
1407 hrtimer_get_softirq_time(cpu_base
);
1411 spin_lock(&cpu_base
->lock
);
1413 while ((node
= base
->first
)) {
1414 struct hrtimer
*timer
;
1416 timer
= rb_entry(node
, struct hrtimer
, node
);
1417 if (base
->softirq_time
.tv64
<= timer
->expires
.tv64
)
1420 if (timer
->cb_mode
== HRTIMER_CB_SOFTIRQ
) {
1421 __remove_hrtimer(timer
, base
,
1422 HRTIMER_STATE_PENDING
, 0);
1423 list_add_tail(&timer
->cb_entry
,
1424 &base
->cpu_base
->cb_pending
);
1428 __run_hrtimer(timer
);
1430 spin_unlock(&cpu_base
->lock
);
1435 * Sleep related functions:
1437 static enum hrtimer_restart
hrtimer_wakeup(struct hrtimer
*timer
)
1439 struct hrtimer_sleeper
*t
=
1440 container_of(timer
, struct hrtimer_sleeper
, timer
);
1441 struct task_struct
*task
= t
->task
;
1445 wake_up_process(task
);
1447 return HRTIMER_NORESTART
;
1450 void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
, struct task_struct
*task
)
1452 sl
->timer
.function
= hrtimer_wakeup
;
1454 #ifdef CONFIG_HIGH_RES_TIMERS
1455 sl
->timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1459 static int __sched
do_nanosleep(struct hrtimer_sleeper
*t
, enum hrtimer_mode mode
)
1461 hrtimer_init_sleeper(t
, current
);
1464 set_current_state(TASK_INTERRUPTIBLE
);
1465 hrtimer_start(&t
->timer
, t
->timer
.expires
, mode
);
1466 if (!hrtimer_active(&t
->timer
))
1469 if (likely(t
->task
))
1472 hrtimer_cancel(&t
->timer
);
1473 mode
= HRTIMER_MODE_ABS
;
1475 } while (t
->task
&& !signal_pending(current
));
1477 __set_current_state(TASK_RUNNING
);
1479 return t
->task
== NULL
;
1482 static int update_rmtp(struct hrtimer
*timer
, struct timespec __user
*rmtp
)
1484 struct timespec rmt
;
1487 rem
= ktime_sub(timer
->expires
, timer
->base
->get_time());
1490 rmt
= ktime_to_timespec(rem
);
1492 if (copy_to_user(rmtp
, &rmt
, sizeof(*rmtp
)))
1498 long __sched
hrtimer_nanosleep_restart(struct restart_block
*restart
)
1500 struct hrtimer_sleeper t
;
1501 struct timespec __user
*rmtp
;
1504 hrtimer_init_on_stack(&t
.timer
, restart
->nanosleep
.index
,
1506 t
.timer
.expires
.tv64
= restart
->nanosleep
.expires
;
1508 if (do_nanosleep(&t
, HRTIMER_MODE_ABS
))
1511 rmtp
= restart
->nanosleep
.rmtp
;
1513 ret
= update_rmtp(&t
.timer
, rmtp
);
1518 /* The other values in restart are already filled in */
1519 ret
= -ERESTART_RESTARTBLOCK
;
1521 destroy_hrtimer_on_stack(&t
.timer
);
1525 long hrtimer_nanosleep(struct timespec
*rqtp
, struct timespec __user
*rmtp
,
1526 const enum hrtimer_mode mode
, const clockid_t clockid
)
1528 struct restart_block
*restart
;
1529 struct hrtimer_sleeper t
;
1532 hrtimer_init_on_stack(&t
.timer
, clockid
, mode
);
1533 t
.timer
.expires
= timespec_to_ktime(*rqtp
);
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_thread_info()->restart_block
;
1550 restart
->fn
= hrtimer_nanosleep_restart
;
1551 restart
->nanosleep
.index
= t
.timer
.base
->index
;
1552 restart
->nanosleep
.rmtp
= rmtp
;
1553 restart
->nanosleep
.expires
= t
.timer
.expires
.tv64
;
1555 ret
= -ERESTART_RESTARTBLOCK
;
1557 destroy_hrtimer_on_stack(&t
.timer
);
1562 sys_nanosleep(struct timespec __user
*rqtp
, 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 __cpuinit
init_hrtimers_cpu(int cpu
)
1580 struct hrtimer_cpu_base
*cpu_base
= &per_cpu(hrtimer_bases
, cpu
);
1583 spin_lock_init(&cpu_base
->lock
);
1585 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++)
1586 cpu_base
->clock_base
[i
].cpu_base
= cpu_base
;
1588 INIT_LIST_HEAD(&cpu_base
->cb_pending
);
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 rb_node
*node
;
1600 while ((node
= rb_first(&old_base
->active
))) {
1601 timer
= rb_entry(node
, struct hrtimer
, node
);
1602 BUG_ON(hrtimer_callback_running(timer
));
1603 debug_hrtimer_deactivate(timer
);
1604 __remove_hrtimer(timer
, old_base
, HRTIMER_STATE_INACTIVE
, 0);
1605 timer
->base
= new_base
;
1607 * Enqueue the timer. Allow reprogramming of the event device
1609 enqueue_hrtimer(timer
, new_base
, 1);
1613 static void migrate_hrtimers(int cpu
)
1615 struct hrtimer_cpu_base
*old_base
, *new_base
;
1618 BUG_ON(cpu_online(cpu
));
1619 old_base
= &per_cpu(hrtimer_bases
, cpu
);
1620 new_base
= &get_cpu_var(hrtimer_bases
);
1622 tick_cancel_sched_timer(cpu
);
1624 local_irq_disable();
1625 spin_lock(&new_base
->lock
);
1626 spin_lock_nested(&old_base
->lock
, SINGLE_DEPTH_NESTING
);
1628 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1629 migrate_hrtimer_list(&old_base
->clock_base
[i
],
1630 &new_base
->clock_base
[i
]);
1633 spin_unlock(&old_base
->lock
);
1634 spin_unlock(&new_base
->lock
);
1636 put_cpu_var(hrtimer_bases
);
1638 #endif /* CONFIG_HOTPLUG_CPU */
1640 static int __cpuinit
hrtimer_cpu_notify(struct notifier_block
*self
,
1641 unsigned long action
, void *hcpu
)
1643 unsigned int cpu
= (long)hcpu
;
1647 case CPU_UP_PREPARE
:
1648 case CPU_UP_PREPARE_FROZEN
:
1649 init_hrtimers_cpu(cpu
);
1652 #ifdef CONFIG_HOTPLUG_CPU
1654 case CPU_DEAD_FROZEN
:
1655 clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD
, &cpu
);
1656 migrate_hrtimers(cpu
);
1667 static struct notifier_block __cpuinitdata hrtimers_nb
= {
1668 .notifier_call
= hrtimer_cpu_notify
,
1671 void __init
hrtimers_init(void)
1673 hrtimer_cpu_notify(&hrtimers_nb
, (unsigned long)CPU_UP_PREPARE
,
1674 (void *)(long)smp_processor_id());
1675 register_cpu_notifier(&hrtimers_nb
);
1676 #ifdef CONFIG_HIGH_RES_TIMERS
1677 open_softirq(HRTIMER_SOFTIRQ
, run_hrtimer_softirq
);
1682 * schedule_hrtimeout - sleep until timeout
1683 * @expires: timeout value (ktime_t)
1684 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1686 * Make the current task sleep until the given expiry time has
1687 * elapsed. The routine will return immediately unless
1688 * the current task state has been set (see set_current_state()).
1690 * You can set the task state as follows -
1692 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1693 * pass before the routine returns.
1695 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1696 * delivered to the current task.
1698 * The current task state is guaranteed to be TASK_RUNNING when this
1701 * Returns 0 when the timer has expired otherwise -EINTR
1703 int __sched
schedule_hrtimeout(ktime_t
*expires
,
1704 const enum hrtimer_mode mode
)
1706 struct hrtimer_sleeper t
;
1709 * Optimize when a zero timeout value is given. It does not
1710 * matter whether this is an absolute or a relative time.
1712 if (expires
&& !expires
->tv64
) {
1713 __set_current_state(TASK_RUNNING
);
1718 * A NULL parameter means "inifinte"
1722 __set_current_state(TASK_RUNNING
);
1726 hrtimer_init_on_stack(&t
.timer
, CLOCK_MONOTONIC
, mode
);
1727 t
.timer
.expires
= *expires
;
1729 hrtimer_init_sleeper(&t
, current
);
1731 hrtimer_start(&t
.timer
, t
.timer
.expires
, mode
);
1732 if (!hrtimer_active(&t
.timer
))
1738 hrtimer_cancel(&t
.timer
);
1739 destroy_hrtimer_on_stack(&t
.timer
);
1741 __set_current_state(TASK_RUNNING
);
1743 return !t
.task
? 0 : -EINTR
;
1745 EXPORT_SYMBOL_GPL(schedule_hrtimeout
);