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
) =
70 .lock
= __RAW_SPIN_LOCK_UNLOCKED(hrtimer_bases
.lock
),
74 .index
= HRTIMER_BASE_MONOTONIC
,
75 .clockid
= CLOCK_MONOTONIC
,
76 .get_time
= &ktime_get
,
77 .resolution
= KTIME_LOW_RES
,
80 .index
= HRTIMER_BASE_REALTIME
,
81 .clockid
= CLOCK_REALTIME
,
82 .get_time
= &ktime_get_real
,
83 .resolution
= KTIME_LOW_RES
,
86 .index
= HRTIMER_BASE_BOOTTIME
,
87 .clockid
= CLOCK_BOOTTIME
,
88 .get_time
= &ktime_get_boottime
,
89 .resolution
= KTIME_LOW_RES
,
92 .index
= HRTIMER_BASE_TAI
,
94 .get_time
= &ktime_get_clocktai
,
95 .resolution
= KTIME_LOW_RES
,
100 static const int hrtimer_clock_to_base_table
[MAX_CLOCKS
] = {
101 [CLOCK_REALTIME
] = HRTIMER_BASE_REALTIME
,
102 [CLOCK_MONOTONIC
] = HRTIMER_BASE_MONOTONIC
,
103 [CLOCK_BOOTTIME
] = HRTIMER_BASE_BOOTTIME
,
104 [CLOCK_TAI
] = HRTIMER_BASE_TAI
,
107 static inline int hrtimer_clockid_to_base(clockid_t clock_id
)
109 return hrtimer_clock_to_base_table
[clock_id
];
114 * Get the coarse grained time at the softirq based on xtime and
117 static void hrtimer_get_softirq_time(struct hrtimer_cpu_base
*base
)
119 ktime_t xtim
, mono
, boot
, tai
;
120 ktime_t off_real
, off_boot
, off_tai
;
122 mono
= ktime_get_update_offsets_tick(&off_real
, &off_boot
, &off_tai
);
123 boot
= ktime_add(mono
, off_boot
);
124 xtim
= ktime_add(mono
, off_real
);
125 tai
= ktime_add(mono
, off_tai
);
127 base
->clock_base
[HRTIMER_BASE_REALTIME
].softirq_time
= xtim
;
128 base
->clock_base
[HRTIMER_BASE_MONOTONIC
].softirq_time
= mono
;
129 base
->clock_base
[HRTIMER_BASE_BOOTTIME
].softirq_time
= boot
;
130 base
->clock_base
[HRTIMER_BASE_TAI
].softirq_time
= tai
;
134 * Functions and macros which are different for UP/SMP systems are kept in a
140 * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
141 * means that all timers which are tied to this base via timer->base are
142 * locked, and the base itself is locked too.
144 * So __run_timers/migrate_timers can safely modify all timers which could
145 * be found on the lists/queues.
147 * When the timer's base is locked, and the timer removed from list, it is
148 * possible to set timer->base = NULL and drop the lock: the timer remains
152 struct hrtimer_clock_base
*lock_hrtimer_base(const struct hrtimer
*timer
,
153 unsigned long *flags
)
155 struct hrtimer_clock_base
*base
;
159 if (likely(base
!= NULL
)) {
160 raw_spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
161 if (likely(base
== timer
->base
))
163 /* The timer has migrated to another CPU: */
164 raw_spin_unlock_irqrestore(&base
->cpu_base
->lock
, *flags
);
171 * With HIGHRES=y we do not migrate the timer when it is expiring
172 * before the next event on the target cpu because we cannot reprogram
173 * the target cpu hardware and we would cause it to fire late.
175 * Called with cpu_base->lock of target cpu held.
178 hrtimer_check_target(struct hrtimer
*timer
, struct hrtimer_clock_base
*new_base
)
180 #ifdef CONFIG_HIGH_RES_TIMERS
183 if (!new_base
->cpu_base
->hres_active
)
186 expires
= ktime_sub(hrtimer_get_expires(timer
), new_base
->offset
);
187 return expires
.tv64
<= new_base
->cpu_base
->expires_next
.tv64
;
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
,
200 struct hrtimer_clock_base
*new_base
;
201 struct hrtimer_cpu_base
*new_cpu_base
;
202 int this_cpu
= smp_processor_id();
203 int cpu
= get_nohz_timer_target(pinned
);
204 int basenum
= base
->index
;
207 new_cpu_base
= &per_cpu(hrtimer_bases
, cpu
);
208 new_base
= &new_cpu_base
->clock_base
[basenum
];
210 if (base
!= new_base
) {
212 * We are trying to move timer to new_base.
213 * However we can't change timer's base while it is running,
214 * so we keep it on the same CPU. No hassle vs. reprogramming
215 * the event source in the high resolution case. The softirq
216 * code will take care of this when the timer function has
217 * completed. There is no conflict as we hold the lock until
218 * the timer is enqueued.
220 if (unlikely(hrtimer_callback_running(timer
)))
223 /* See the comment in lock_timer_base() */
225 raw_spin_unlock(&base
->cpu_base
->lock
);
226 raw_spin_lock(&new_base
->cpu_base
->lock
);
228 if (cpu
!= this_cpu
&& hrtimer_check_target(timer
, new_base
)) {
230 raw_spin_unlock(&new_base
->cpu_base
->lock
);
231 raw_spin_lock(&base
->cpu_base
->lock
);
235 timer
->base
= new_base
;
237 if (cpu
!= this_cpu
&& hrtimer_check_target(timer
, new_base
)) {
245 #else /* CONFIG_SMP */
247 static inline struct hrtimer_clock_base
*
248 lock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
250 struct hrtimer_clock_base
*base
= timer
->base
;
252 raw_spin_lock_irqsave(&base
->cpu_base
->lock
, *flags
);
257 # define switch_hrtimer_base(t, b, p) (b)
259 #endif /* !CONFIG_SMP */
262 * Functions for the union type storage format of ktime_t which are
263 * too large for inlining:
265 #if BITS_PER_LONG < 64
267 * Divide a ktime value by a nanosecond value
269 s64
__ktime_divns(const ktime_t kt
, s64 div
)
275 dclc
= ktime_to_ns(kt
);
276 tmp
= dclc
< 0 ? -dclc
: dclc
;
278 /* Make sure the divisor is less than 2^32: */
284 do_div(tmp
, (unsigned long) div
);
285 return dclc
< 0 ? -tmp
: tmp
;
287 EXPORT_SYMBOL_GPL(__ktime_divns
);
288 #endif /* BITS_PER_LONG >= 64 */
291 * Add two ktime values and do a safety check for overflow:
293 ktime_t
ktime_add_safe(const ktime_t lhs
, const ktime_t rhs
)
295 ktime_t res
= ktime_add(lhs
, rhs
);
298 * We use KTIME_SEC_MAX here, the maximum timeout which we can
299 * return to user space in a timespec:
301 if (res
.tv64
< 0 || res
.tv64
< lhs
.tv64
|| res
.tv64
< rhs
.tv64
)
302 res
= ktime_set(KTIME_SEC_MAX
, 0);
307 EXPORT_SYMBOL_GPL(ktime_add_safe
);
309 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
311 static struct debug_obj_descr hrtimer_debug_descr
;
313 static void *hrtimer_debug_hint(void *addr
)
315 return ((struct hrtimer
*) addr
)->function
;
319 * fixup_init is called when:
320 * - an active object is initialized
322 static int hrtimer_fixup_init(void *addr
, enum debug_obj_state state
)
324 struct hrtimer
*timer
= addr
;
327 case ODEBUG_STATE_ACTIVE
:
328 hrtimer_cancel(timer
);
329 debug_object_init(timer
, &hrtimer_debug_descr
);
337 * fixup_activate is called when:
338 * - an active object is activated
339 * - an unknown object is activated (might be a statically initialized object)
341 static int hrtimer_fixup_activate(void *addr
, enum debug_obj_state state
)
345 case ODEBUG_STATE_NOTAVAILABLE
:
349 case ODEBUG_STATE_ACTIVE
:
358 * fixup_free is called when:
359 * - an active object is freed
361 static int hrtimer_fixup_free(void *addr
, enum debug_obj_state state
)
363 struct hrtimer
*timer
= addr
;
366 case ODEBUG_STATE_ACTIVE
:
367 hrtimer_cancel(timer
);
368 debug_object_free(timer
, &hrtimer_debug_descr
);
375 static struct debug_obj_descr hrtimer_debug_descr
= {
377 .debug_hint
= hrtimer_debug_hint
,
378 .fixup_init
= hrtimer_fixup_init
,
379 .fixup_activate
= hrtimer_fixup_activate
,
380 .fixup_free
= hrtimer_fixup_free
,
383 static inline void debug_hrtimer_init(struct hrtimer
*timer
)
385 debug_object_init(timer
, &hrtimer_debug_descr
);
388 static inline void debug_hrtimer_activate(struct hrtimer
*timer
)
390 debug_object_activate(timer
, &hrtimer_debug_descr
);
393 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
)
395 debug_object_deactivate(timer
, &hrtimer_debug_descr
);
398 static inline void debug_hrtimer_free(struct hrtimer
*timer
)
400 debug_object_free(timer
, &hrtimer_debug_descr
);
403 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
404 enum hrtimer_mode mode
);
406 void hrtimer_init_on_stack(struct hrtimer
*timer
, clockid_t clock_id
,
407 enum hrtimer_mode mode
)
409 debug_object_init_on_stack(timer
, &hrtimer_debug_descr
);
410 __hrtimer_init(timer
, clock_id
, mode
);
412 EXPORT_SYMBOL_GPL(hrtimer_init_on_stack
);
414 void destroy_hrtimer_on_stack(struct hrtimer
*timer
)
416 debug_object_free(timer
, &hrtimer_debug_descr
);
420 static inline void debug_hrtimer_init(struct hrtimer
*timer
) { }
421 static inline void debug_hrtimer_activate(struct hrtimer
*timer
) { }
422 static inline void debug_hrtimer_deactivate(struct hrtimer
*timer
) { }
426 debug_init(struct hrtimer
*timer
, clockid_t clockid
,
427 enum hrtimer_mode mode
)
429 debug_hrtimer_init(timer
);
430 trace_hrtimer_init(timer
, clockid
, mode
);
433 static inline void debug_activate(struct hrtimer
*timer
)
435 debug_hrtimer_activate(timer
);
436 trace_hrtimer_start(timer
);
439 static inline void debug_deactivate(struct hrtimer
*timer
)
441 debug_hrtimer_deactivate(timer
);
442 trace_hrtimer_cancel(timer
);
445 #if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
446 static ktime_t
__hrtimer_get_next_event(struct hrtimer_cpu_base
*cpu_base
)
448 struct hrtimer_clock_base
*base
= cpu_base
->clock_base
;
449 ktime_t expires
, expires_next
= { .tv64
= KTIME_MAX
};
452 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++, base
++) {
453 struct timerqueue_node
*next
;
454 struct hrtimer
*timer
;
456 next
= timerqueue_getnext(&base
->active
);
460 timer
= container_of(next
, struct hrtimer
, node
);
461 expires
= ktime_sub(hrtimer_get_expires(timer
), base
->offset
);
462 if (expires
.tv64
< expires_next
.tv64
)
463 expires_next
= expires
;
466 * clock_was_set() might have changed base->offset of any of
467 * the clock bases so the result might be negative. Fix it up
468 * to prevent a false positive in clockevents_program_event().
470 if (expires_next
.tv64
< 0)
471 expires_next
.tv64
= 0;
476 /* High resolution timer related functions */
477 #ifdef CONFIG_HIGH_RES_TIMERS
480 * High resolution timer enabled ?
482 static int hrtimer_hres_enabled __read_mostly
= 1;
485 * Enable / Disable high resolution mode
487 static int __init
setup_hrtimer_hres(char *str
)
489 if (!strcmp(str
, "off"))
490 hrtimer_hres_enabled
= 0;
491 else if (!strcmp(str
, "on"))
492 hrtimer_hres_enabled
= 1;
498 __setup("highres=", setup_hrtimer_hres
);
501 * hrtimer_high_res_enabled - query, if the highres mode is enabled
503 static inline int hrtimer_is_hres_enabled(void)
505 return hrtimer_hres_enabled
;
509 * Is the high resolution mode active ?
511 static inline int hrtimer_hres_active(void)
513 return __this_cpu_read(hrtimer_bases
.hres_active
);
517 * Reprogram the event source with checking both queues for the
519 * Called with interrupts disabled and base->lock held
522 hrtimer_force_reprogram(struct hrtimer_cpu_base
*cpu_base
, int skip_equal
)
524 ktime_t expires_next
= __hrtimer_get_next_event(cpu_base
);
526 if (skip_equal
&& expires_next
.tv64
== cpu_base
->expires_next
.tv64
)
529 cpu_base
->expires_next
.tv64
= expires_next
.tv64
;
532 * If a hang was detected in the last timer interrupt then we
533 * leave the hang delay active in the hardware. We want the
534 * system to make progress. That also prevents the following
536 * T1 expires 50ms from now
537 * T2 expires 5s from now
539 * T1 is removed, so this code is called and would reprogram
540 * the hardware to 5s from now. Any hrtimer_start after that
541 * will not reprogram the hardware due to hang_detected being
542 * set. So we'd effectivly block all timers until the T2 event
545 if (cpu_base
->hang_detected
)
548 if (cpu_base
->expires_next
.tv64
!= KTIME_MAX
)
549 tick_program_event(cpu_base
->expires_next
, 1);
553 * Shared reprogramming for clock_realtime and clock_monotonic
555 * When a timer is enqueued and expires earlier than the already enqueued
556 * timers, we have to check, whether it expires earlier than the timer for
557 * which the clock event device was armed.
559 * Note, that in case the state has HRTIMER_STATE_CALLBACK set, no reprogramming
560 * and no expiry check happens. The timer gets enqueued into the rbtree. The
561 * reprogramming and expiry check is done in the hrtimer_interrupt or in the
564 * Called with interrupts disabled and base->cpu_base.lock held
566 static int hrtimer_reprogram(struct hrtimer
*timer
,
567 struct hrtimer_clock_base
*base
)
569 struct hrtimer_cpu_base
*cpu_base
= this_cpu_ptr(&hrtimer_bases
);
570 ktime_t expires
= ktime_sub(hrtimer_get_expires(timer
), base
->offset
);
573 WARN_ON_ONCE(hrtimer_get_expires_tv64(timer
) < 0);
576 * When the callback is running, we do not reprogram the clock event
577 * device. The timer callback is either running on a different CPU or
578 * the callback is executed in the hrtimer_interrupt context. The
579 * reprogramming is handled either by the softirq, which called the
580 * callback or at the end of the hrtimer_interrupt.
582 if (hrtimer_callback_running(timer
))
586 * CLOCK_REALTIME timer might be requested with an absolute
587 * expiry time which is less than base->offset. Nothing wrong
588 * about that, just avoid to call into the tick code, which
589 * has now objections against negative expiry values.
591 if (expires
.tv64
< 0)
594 if (expires
.tv64
>= cpu_base
->expires_next
.tv64
)
598 * When the target cpu of the timer is currently executing
599 * hrtimer_interrupt(), then we do not touch the clock event
600 * device. hrtimer_interrupt() will reevaluate all clock bases
601 * before reprogramming the device.
603 if (cpu_base
->in_hrtirq
)
607 * If a hang was detected in the last timer interrupt then we
608 * do not schedule a timer which is earlier than the expiry
609 * which we enforced in the hang detection. We want the system
612 if (cpu_base
->hang_detected
)
616 * Clockevents returns -ETIME, when the event was in the past.
618 res
= tick_program_event(expires
, 0);
619 if (!IS_ERR_VALUE(res
))
620 cpu_base
->expires_next
= expires
;
625 * Initialize the high resolution related parts of cpu_base
627 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
)
629 base
->expires_next
.tv64
= KTIME_MAX
;
630 base
->hres_active
= 0;
633 static inline ktime_t
hrtimer_update_base(struct hrtimer_cpu_base
*base
)
635 ktime_t
*offs_real
= &base
->clock_base
[HRTIMER_BASE_REALTIME
].offset
;
636 ktime_t
*offs_boot
= &base
->clock_base
[HRTIMER_BASE_BOOTTIME
].offset
;
637 ktime_t
*offs_tai
= &base
->clock_base
[HRTIMER_BASE_TAI
].offset
;
639 return ktime_get_update_offsets_now(offs_real
, offs_boot
, offs_tai
);
643 * Retrigger next event is called after clock was set
645 * Called with interrupts disabled via on_each_cpu()
647 static void retrigger_next_event(void *arg
)
649 struct hrtimer_cpu_base
*base
= this_cpu_ptr(&hrtimer_bases
);
651 if (!hrtimer_hres_active())
654 raw_spin_lock(&base
->lock
);
655 hrtimer_update_base(base
);
656 hrtimer_force_reprogram(base
, 0);
657 raw_spin_unlock(&base
->lock
);
661 * Switch to high resolution mode
663 static int hrtimer_switch_to_hres(void)
665 int i
, cpu
= smp_processor_id();
666 struct hrtimer_cpu_base
*base
= &per_cpu(hrtimer_bases
, cpu
);
669 if (base
->hres_active
)
672 local_irq_save(flags
);
674 if (tick_init_highres()) {
675 local_irq_restore(flags
);
676 printk(KERN_WARNING
"Could not switch to high resolution "
677 "mode on CPU %d\n", cpu
);
680 base
->hres_active
= 1;
681 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++)
682 base
->clock_base
[i
].resolution
= KTIME_HIGH_RES
;
684 tick_setup_sched_timer();
685 /* "Retrigger" the interrupt to get things going */
686 retrigger_next_event(NULL
);
687 local_irq_restore(flags
);
691 static void clock_was_set_work(struct work_struct
*work
)
696 static DECLARE_WORK(hrtimer_work
, clock_was_set_work
);
699 * Called from timekeeping and resume code to reprogramm the hrtimer
700 * interrupt device on all cpus.
702 void clock_was_set_delayed(void)
704 schedule_work(&hrtimer_work
);
709 static inline int hrtimer_hres_active(void) { return 0; }
710 static inline int hrtimer_is_hres_enabled(void) { return 0; }
711 static inline int hrtimer_switch_to_hres(void) { return 0; }
713 hrtimer_force_reprogram(struct hrtimer_cpu_base
*base
, int skip_equal
) { }
714 static inline int hrtimer_reprogram(struct hrtimer
*timer
,
715 struct hrtimer_clock_base
*base
)
719 static inline void hrtimer_init_hres(struct hrtimer_cpu_base
*base
) { }
720 static inline void retrigger_next_event(void *arg
) { }
722 #endif /* CONFIG_HIGH_RES_TIMERS */
725 * Clock realtime was set
727 * Change the offset of the realtime clock vs. the monotonic
730 * We might have to reprogram the high resolution timer interrupt. On
731 * SMP we call the architecture specific code to retrigger _all_ high
732 * resolution timer interrupts. On UP we just disable interrupts and
733 * call the high resolution interrupt code.
735 void clock_was_set(void)
737 #ifdef CONFIG_HIGH_RES_TIMERS
738 /* Retrigger the CPU local events everywhere */
739 on_each_cpu(retrigger_next_event
, NULL
, 1);
741 timerfd_clock_was_set();
745 * During resume we might have to reprogram the high resolution timer
746 * interrupt on all online CPUs. However, all other CPUs will be
747 * stopped with IRQs interrupts disabled so the clock_was_set() call
750 void hrtimers_resume(void)
752 WARN_ONCE(!irqs_disabled(),
753 KERN_INFO
"hrtimers_resume() called with IRQs enabled!");
755 /* Retrigger on the local CPU */
756 retrigger_next_event(NULL
);
757 /* And schedule a retrigger for all others */
758 clock_was_set_delayed();
761 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer
*timer
)
763 #ifdef CONFIG_TIMER_STATS
764 if (timer
->start_site
)
766 timer
->start_site
= __builtin_return_address(0);
767 memcpy(timer
->start_comm
, current
->comm
, TASK_COMM_LEN
);
768 timer
->start_pid
= current
->pid
;
772 static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer
*timer
)
774 #ifdef CONFIG_TIMER_STATS
775 timer
->start_site
= NULL
;
779 static inline void timer_stats_account_hrtimer(struct hrtimer
*timer
)
781 #ifdef CONFIG_TIMER_STATS
782 if (likely(!timer_stats_active
))
784 timer_stats_update_stats(timer
, timer
->start_pid
, timer
->start_site
,
785 timer
->function
, timer
->start_comm
, 0);
790 * Counterpart to lock_hrtimer_base above:
793 void unlock_hrtimer_base(const struct hrtimer
*timer
, unsigned long *flags
)
795 raw_spin_unlock_irqrestore(&timer
->base
->cpu_base
->lock
, *flags
);
799 * hrtimer_forward - forward the timer expiry
800 * @timer: hrtimer to forward
801 * @now: forward past this time
802 * @interval: the interval to forward
804 * Forward the timer expiry so it will expire in the future.
805 * Returns the number of overruns.
807 u64
hrtimer_forward(struct hrtimer
*timer
, ktime_t now
, ktime_t interval
)
812 delta
= ktime_sub(now
, hrtimer_get_expires(timer
));
817 if (interval
.tv64
< timer
->base
->resolution
.tv64
)
818 interval
.tv64
= timer
->base
->resolution
.tv64
;
820 if (unlikely(delta
.tv64
>= interval
.tv64
)) {
821 s64 incr
= ktime_to_ns(interval
);
823 orun
= ktime_divns(delta
, incr
);
824 hrtimer_add_expires_ns(timer
, incr
* orun
);
825 if (hrtimer_get_expires_tv64(timer
) > now
.tv64
)
828 * This (and the ktime_add() below) is the
829 * correction for exact:
833 hrtimer_add_expires(timer
, interval
);
837 EXPORT_SYMBOL_GPL(hrtimer_forward
);
840 * enqueue_hrtimer - internal function to (re)start a timer
842 * The timer is inserted in expiry order. Insertion into the
843 * red black tree is O(log(n)). Must hold the base lock.
845 * Returns 1 when the new timer is the leftmost timer in the tree.
847 static int enqueue_hrtimer(struct hrtimer
*timer
,
848 struct hrtimer_clock_base
*base
)
850 debug_activate(timer
);
852 timerqueue_add(&base
->active
, &timer
->node
);
853 base
->cpu_base
->active_bases
|= 1 << base
->index
;
856 * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
857 * state of a possibly running callback.
859 timer
->state
|= HRTIMER_STATE_ENQUEUED
;
861 return (&timer
->node
== base
->active
.next
);
865 * __remove_hrtimer - internal function to remove a timer
867 * Caller must hold the base lock.
869 * High resolution timer mode reprograms the clock event device when the
870 * timer is the one which expires next. The caller can disable this by setting
871 * reprogram to zero. This is useful, when the context does a reprogramming
872 * anyway (e.g. timer interrupt)
874 static void __remove_hrtimer(struct hrtimer
*timer
,
875 struct hrtimer_clock_base
*base
,
876 unsigned long newstate
, int reprogram
)
878 struct timerqueue_node
*next_timer
;
879 if (!(timer
->state
& HRTIMER_STATE_ENQUEUED
))
882 next_timer
= timerqueue_getnext(&base
->active
);
883 timerqueue_del(&base
->active
, &timer
->node
);
884 if (&timer
->node
== next_timer
) {
885 #ifdef CONFIG_HIGH_RES_TIMERS
886 /* Reprogram the clock event device. if enabled */
887 if (reprogram
&& hrtimer_hres_active()) {
890 expires
= ktime_sub(hrtimer_get_expires(timer
),
892 if (base
->cpu_base
->expires_next
.tv64
== expires
.tv64
)
893 hrtimer_force_reprogram(base
->cpu_base
, 1);
897 if (!timerqueue_getnext(&base
->active
))
898 base
->cpu_base
->active_bases
&= ~(1 << base
->index
);
900 timer
->state
= newstate
;
904 * remove hrtimer, called with base lock held
907 remove_hrtimer(struct hrtimer
*timer
, struct hrtimer_clock_base
*base
)
909 if (hrtimer_is_queued(timer
)) {
914 * Remove the timer and force reprogramming when high
915 * resolution mode is active and the timer is on the current
916 * CPU. If we remove a timer on another CPU, reprogramming is
917 * skipped. The interrupt event on this CPU is fired and
918 * reprogramming happens in the interrupt handler. This is a
919 * rare case and less expensive than a smp call.
921 debug_deactivate(timer
);
922 timer_stats_hrtimer_clear_start_info(timer
);
923 reprogram
= base
->cpu_base
== this_cpu_ptr(&hrtimer_bases
);
925 * We must preserve the CALLBACK state flag here,
926 * otherwise we could move the timer base in
927 * switch_hrtimer_base.
929 state
= timer
->state
& HRTIMER_STATE_CALLBACK
;
930 __remove_hrtimer(timer
, base
, state
, reprogram
);
936 int __hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
937 unsigned long delta_ns
, const enum hrtimer_mode mode
,
940 struct hrtimer_clock_base
*base
, *new_base
;
944 base
= lock_hrtimer_base(timer
, &flags
);
946 /* Remove an active timer from the queue: */
947 ret
= remove_hrtimer(timer
, base
);
949 if (mode
& HRTIMER_MODE_REL
) {
950 tim
= ktime_add_safe(tim
, base
->get_time());
952 * CONFIG_TIME_LOW_RES is a temporary way for architectures
953 * to signal that they simply return xtime in
954 * do_gettimeoffset(). In this case we want to round up by
955 * resolution when starting a relative timer, to avoid short
956 * timeouts. This will go away with the GTOD framework.
958 #ifdef CONFIG_TIME_LOW_RES
959 tim
= ktime_add_safe(tim
, base
->resolution
);
963 hrtimer_set_expires_range_ns(timer
, tim
, delta_ns
);
965 /* Switch the timer base, if necessary: */
966 new_base
= switch_hrtimer_base(timer
, base
, mode
& HRTIMER_MODE_PINNED
);
968 timer_stats_hrtimer_set_start_info(timer
);
970 leftmost
= enqueue_hrtimer(timer
, new_base
);
973 unlock_hrtimer_base(timer
, &flags
);
977 if (!hrtimer_is_hres_active(timer
)) {
979 * Kick to reschedule the next tick to handle the new timer
980 * on dynticks target.
982 wake_up_nohz_cpu(new_base
->cpu_base
->cpu
);
983 } else if (new_base
->cpu_base
== this_cpu_ptr(&hrtimer_bases
) &&
984 hrtimer_reprogram(timer
, new_base
)) {
986 * Only allow reprogramming if the new base is on this CPU.
987 * (it might still be on another CPU if the timer was pending)
989 * XXX send_remote_softirq() ?
993 * We need to drop cpu_base->lock to avoid a
994 * lock ordering issue vs. rq->lock.
996 raw_spin_unlock(&new_base
->cpu_base
->lock
);
997 raise_softirq_irqoff(HRTIMER_SOFTIRQ
);
998 local_irq_restore(flags
);
1001 __raise_softirq_irqoff(HRTIMER_SOFTIRQ
);
1005 unlock_hrtimer_base(timer
, &flags
);
1009 EXPORT_SYMBOL_GPL(__hrtimer_start_range_ns
);
1012 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
1013 * @timer: the timer to be added
1015 * @delta_ns: "slack" range for the timer
1016 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
1017 * relative (HRTIMER_MODE_REL)
1021 * 1 when the timer was active
1023 int hrtimer_start_range_ns(struct hrtimer
*timer
, ktime_t tim
,
1024 unsigned long delta_ns
, const enum hrtimer_mode mode
)
1026 return __hrtimer_start_range_ns(timer
, tim
, delta_ns
, mode
, 1);
1028 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns
);
1031 * hrtimer_start - (re)start an hrtimer on the current CPU
1032 * @timer: the timer to be added
1034 * @mode: expiry mode: absolute (HRTIMER_MODE_ABS) or
1035 * relative (HRTIMER_MODE_REL)
1039 * 1 when the timer was active
1042 hrtimer_start(struct hrtimer
*timer
, ktime_t tim
, const enum hrtimer_mode mode
)
1044 return __hrtimer_start_range_ns(timer
, tim
, 0, mode
, 1);
1046 EXPORT_SYMBOL_GPL(hrtimer_start
);
1050 * hrtimer_try_to_cancel - try to deactivate a timer
1051 * @timer: hrtimer to stop
1054 * 0 when the timer was not active
1055 * 1 when the timer was active
1056 * -1 when the timer is currently excuting the callback function and
1059 int hrtimer_try_to_cancel(struct hrtimer
*timer
)
1061 struct hrtimer_clock_base
*base
;
1062 unsigned long flags
;
1065 base
= lock_hrtimer_base(timer
, &flags
);
1067 if (!hrtimer_callback_running(timer
))
1068 ret
= remove_hrtimer(timer
, base
);
1070 unlock_hrtimer_base(timer
, &flags
);
1075 EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel
);
1078 * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1079 * @timer: the timer to be cancelled
1082 * 0 when the timer was not active
1083 * 1 when the timer was active
1085 int hrtimer_cancel(struct hrtimer
*timer
)
1088 int ret
= hrtimer_try_to_cancel(timer
);
1095 EXPORT_SYMBOL_GPL(hrtimer_cancel
);
1098 * hrtimer_get_remaining - get remaining time for the timer
1099 * @timer: the timer to read
1101 ktime_t
hrtimer_get_remaining(const struct hrtimer
*timer
)
1103 unsigned long flags
;
1106 lock_hrtimer_base(timer
, &flags
);
1107 rem
= hrtimer_expires_remaining(timer
);
1108 unlock_hrtimer_base(timer
, &flags
);
1112 EXPORT_SYMBOL_GPL(hrtimer_get_remaining
);
1114 #ifdef CONFIG_NO_HZ_COMMON
1116 * hrtimer_get_next_event - get the time until next expiry event
1118 * Returns the delta to the next expiry event or KTIME_MAX if no timer
1121 ktime_t
hrtimer_get_next_event(void)
1123 struct hrtimer_cpu_base
*cpu_base
= this_cpu_ptr(&hrtimer_bases
);
1124 ktime_t mindelta
= { .tv64
= KTIME_MAX
};
1125 unsigned long flags
;
1127 raw_spin_lock_irqsave(&cpu_base
->lock
, flags
);
1129 if (!hrtimer_hres_active())
1130 mindelta
= ktime_sub(__hrtimer_get_next_event(cpu_base
),
1133 raw_spin_unlock_irqrestore(&cpu_base
->lock
, flags
);
1135 if (mindelta
.tv64
< 0)
1141 static void __hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1142 enum hrtimer_mode mode
)
1144 struct hrtimer_cpu_base
*cpu_base
;
1147 memset(timer
, 0, sizeof(struct hrtimer
));
1149 cpu_base
= raw_cpu_ptr(&hrtimer_bases
);
1151 if (clock_id
== CLOCK_REALTIME
&& mode
!= HRTIMER_MODE_ABS
)
1152 clock_id
= CLOCK_MONOTONIC
;
1154 base
= hrtimer_clockid_to_base(clock_id
);
1155 timer
->base
= &cpu_base
->clock_base
[base
];
1156 timerqueue_init(&timer
->node
);
1158 #ifdef CONFIG_TIMER_STATS
1159 timer
->start_site
= NULL
;
1160 timer
->start_pid
= -1;
1161 memset(timer
->start_comm
, 0, TASK_COMM_LEN
);
1166 * hrtimer_init - initialize a timer to the given clock
1167 * @timer: the timer to be initialized
1168 * @clock_id: the clock to be used
1169 * @mode: timer mode abs/rel
1171 void hrtimer_init(struct hrtimer
*timer
, clockid_t clock_id
,
1172 enum hrtimer_mode mode
)
1174 debug_init(timer
, clock_id
, mode
);
1175 __hrtimer_init(timer
, clock_id
, mode
);
1177 EXPORT_SYMBOL_GPL(hrtimer_init
);
1180 * hrtimer_get_res - get the timer resolution for a clock
1181 * @which_clock: which clock to query
1182 * @tp: pointer to timespec variable to store the resolution
1184 * Store the resolution of the clock selected by @which_clock in the
1185 * variable pointed to by @tp.
1187 int hrtimer_get_res(const clockid_t which_clock
, struct timespec
*tp
)
1189 struct hrtimer_cpu_base
*cpu_base
;
1190 int base
= hrtimer_clockid_to_base(which_clock
);
1192 cpu_base
= raw_cpu_ptr(&hrtimer_bases
);
1193 *tp
= ktime_to_timespec(cpu_base
->clock_base
[base
].resolution
);
1197 EXPORT_SYMBOL_GPL(hrtimer_get_res
);
1199 static void __run_hrtimer(struct hrtimer
*timer
, ktime_t
*now
)
1201 struct hrtimer_clock_base
*base
= timer
->base
;
1202 struct hrtimer_cpu_base
*cpu_base
= base
->cpu_base
;
1203 enum hrtimer_restart (*fn
)(struct hrtimer
*);
1206 WARN_ON(!irqs_disabled());
1208 debug_deactivate(timer
);
1209 __remove_hrtimer(timer
, base
, HRTIMER_STATE_CALLBACK
, 0);
1210 timer_stats_account_hrtimer(timer
);
1211 fn
= timer
->function
;
1214 * Because we run timers from hardirq context, there is no chance
1215 * they get migrated to another cpu, therefore its safe to unlock
1218 raw_spin_unlock(&cpu_base
->lock
);
1219 trace_hrtimer_expire_entry(timer
, now
);
1220 restart
= fn(timer
);
1221 trace_hrtimer_expire_exit(timer
);
1222 raw_spin_lock(&cpu_base
->lock
);
1225 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
1226 * we do not reprogramm the event hardware. Happens either in
1227 * hrtimer_start_range_ns() or in hrtimer_interrupt()
1229 if (restart
!= HRTIMER_NORESTART
) {
1230 BUG_ON(timer
->state
!= HRTIMER_STATE_CALLBACK
);
1231 enqueue_hrtimer(timer
, base
);
1234 WARN_ON_ONCE(!(timer
->state
& HRTIMER_STATE_CALLBACK
));
1236 timer
->state
&= ~HRTIMER_STATE_CALLBACK
;
1239 #ifdef CONFIG_HIGH_RES_TIMERS
1242 * High resolution timer interrupt
1243 * Called with interrupts disabled
1245 void hrtimer_interrupt(struct clock_event_device
*dev
)
1247 struct hrtimer_cpu_base
*cpu_base
= this_cpu_ptr(&hrtimer_bases
);
1248 ktime_t expires_next
, now
, entry_time
, delta
;
1251 BUG_ON(!cpu_base
->hres_active
);
1252 cpu_base
->nr_events
++;
1253 dev
->next_event
.tv64
= KTIME_MAX
;
1255 raw_spin_lock(&cpu_base
->lock
);
1256 entry_time
= now
= hrtimer_update_base(cpu_base
);
1258 cpu_base
->in_hrtirq
= 1;
1260 * We set expires_next to KTIME_MAX here with cpu_base->lock
1261 * held to prevent that a timer is enqueued in our queue via
1262 * the migration code. This does not affect enqueueing of
1263 * timers which run their callback and need to be requeued on
1266 cpu_base
->expires_next
.tv64
= KTIME_MAX
;
1268 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1269 struct hrtimer_clock_base
*base
;
1270 struct timerqueue_node
*node
;
1273 if (!(cpu_base
->active_bases
& (1 << i
)))
1276 base
= cpu_base
->clock_base
+ i
;
1277 basenow
= ktime_add(now
, base
->offset
);
1279 while ((node
= timerqueue_getnext(&base
->active
))) {
1280 struct hrtimer
*timer
;
1282 timer
= container_of(node
, struct hrtimer
, node
);
1285 * The immediate goal for using the softexpires is
1286 * minimizing wakeups, not running timers at the
1287 * earliest interrupt after their soft expiration.
1288 * This allows us to avoid using a Priority Search
1289 * Tree, which can answer a stabbing querry for
1290 * overlapping intervals and instead use the simple
1291 * BST we already have.
1292 * We don't add extra wakeups by delaying timers that
1293 * are right-of a not yet expired timer, because that
1294 * timer will have to trigger a wakeup anyway.
1296 if (basenow
.tv64
< hrtimer_get_softexpires_tv64(timer
))
1299 __run_hrtimer(timer
, &basenow
);
1302 /* Reevaluate the clock bases for the next expiry */
1303 expires_next
= __hrtimer_get_next_event(cpu_base
);
1305 * Store the new expiry value so the migration code can verify
1308 cpu_base
->expires_next
= expires_next
;
1309 cpu_base
->in_hrtirq
= 0;
1310 raw_spin_unlock(&cpu_base
->lock
);
1312 /* Reprogramming necessary ? */
1313 if (expires_next
.tv64
== KTIME_MAX
||
1314 !tick_program_event(expires_next
, 0)) {
1315 cpu_base
->hang_detected
= 0;
1320 * The next timer was already expired due to:
1322 * - long lasting callbacks
1323 * - being scheduled away when running in a VM
1325 * We need to prevent that we loop forever in the hrtimer
1326 * interrupt routine. We give it 3 attempts to avoid
1327 * overreacting on some spurious event.
1329 * Acquire base lock for updating the offsets and retrieving
1332 raw_spin_lock(&cpu_base
->lock
);
1333 now
= hrtimer_update_base(cpu_base
);
1334 cpu_base
->nr_retries
++;
1338 * Give the system a chance to do something else than looping
1339 * here. We stored the entry time, so we know exactly how long
1340 * we spent here. We schedule the next event this amount of
1343 cpu_base
->nr_hangs
++;
1344 cpu_base
->hang_detected
= 1;
1345 raw_spin_unlock(&cpu_base
->lock
);
1346 delta
= ktime_sub(now
, entry_time
);
1347 if (delta
.tv64
> cpu_base
->max_hang_time
.tv64
)
1348 cpu_base
->max_hang_time
= delta
;
1350 * Limit it to a sensible value as we enforce a longer
1351 * delay. Give the CPU at least 100ms to catch up.
1353 if (delta
.tv64
> 100 * NSEC_PER_MSEC
)
1354 expires_next
= ktime_add_ns(now
, 100 * NSEC_PER_MSEC
);
1356 expires_next
= ktime_add(now
, delta
);
1357 tick_program_event(expires_next
, 1);
1358 printk_once(KERN_WARNING
"hrtimer: interrupt took %llu ns\n",
1359 ktime_to_ns(delta
));
1363 * local version of hrtimer_peek_ahead_timers() called with interrupts
1366 static void __hrtimer_peek_ahead_timers(void)
1368 struct tick_device
*td
;
1370 if (!hrtimer_hres_active())
1373 td
= this_cpu_ptr(&tick_cpu_device
);
1374 if (td
&& td
->evtdev
)
1375 hrtimer_interrupt(td
->evtdev
);
1379 * hrtimer_peek_ahead_timers -- run soft-expired timers now
1381 * hrtimer_peek_ahead_timers will peek at the timer queue of
1382 * the current cpu and check if there are any timers for which
1383 * the soft expires time has passed. If any such timers exist,
1384 * they are run immediately and then removed from the timer queue.
1387 void hrtimer_peek_ahead_timers(void)
1389 unsigned long flags
;
1391 local_irq_save(flags
);
1392 __hrtimer_peek_ahead_timers();
1393 local_irq_restore(flags
);
1396 static void run_hrtimer_softirq(struct softirq_action
*h
)
1398 hrtimer_peek_ahead_timers();
1401 #else /* CONFIG_HIGH_RES_TIMERS */
1403 static inline void __hrtimer_peek_ahead_timers(void) { }
1405 #endif /* !CONFIG_HIGH_RES_TIMERS */
1408 * Called from timer softirq every jiffy, expire hrtimers:
1410 * For HRT its the fall back code to run the softirq in the timer
1411 * softirq context in case the hrtimer initialization failed or has
1412 * not been done yet.
1414 void hrtimer_run_pending(void)
1416 if (hrtimer_hres_active())
1420 * This _is_ ugly: We have to check in the softirq context,
1421 * whether we can switch to highres and / or nohz mode. The
1422 * clocksource switch happens in the timer interrupt with
1423 * xtime_lock held. Notification from there only sets the
1424 * check bit in the tick_oneshot code, otherwise we might
1425 * deadlock vs. xtime_lock.
1427 if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
1428 hrtimer_switch_to_hres();
1432 * Called from hardirq context every jiffy
1434 void hrtimer_run_queues(void)
1436 struct timerqueue_node
*node
;
1437 struct hrtimer_cpu_base
*cpu_base
= this_cpu_ptr(&hrtimer_bases
);
1438 struct hrtimer_clock_base
*base
;
1439 int index
, gettime
= 1;
1441 if (hrtimer_hres_active())
1444 for (index
= 0; index
< HRTIMER_MAX_CLOCK_BASES
; index
++) {
1445 base
= &cpu_base
->clock_base
[index
];
1446 if (!timerqueue_getnext(&base
->active
))
1450 hrtimer_get_softirq_time(cpu_base
);
1454 raw_spin_lock(&cpu_base
->lock
);
1456 while ((node
= timerqueue_getnext(&base
->active
))) {
1457 struct hrtimer
*timer
;
1459 timer
= container_of(node
, struct hrtimer
, node
);
1460 if (base
->softirq_time
.tv64
<=
1461 hrtimer_get_expires_tv64(timer
))
1464 __run_hrtimer(timer
, &base
->softirq_time
);
1466 raw_spin_unlock(&cpu_base
->lock
);
1471 * Sleep related functions:
1473 static enum hrtimer_restart
hrtimer_wakeup(struct hrtimer
*timer
)
1475 struct hrtimer_sleeper
*t
=
1476 container_of(timer
, struct hrtimer_sleeper
, timer
);
1477 struct task_struct
*task
= t
->task
;
1481 wake_up_process(task
);
1483 return HRTIMER_NORESTART
;
1486 void hrtimer_init_sleeper(struct hrtimer_sleeper
*sl
, struct task_struct
*task
)
1488 sl
->timer
.function
= hrtimer_wakeup
;
1491 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper
);
1493 static int __sched
do_nanosleep(struct hrtimer_sleeper
*t
, enum hrtimer_mode mode
)
1495 hrtimer_init_sleeper(t
, current
);
1498 set_current_state(TASK_INTERRUPTIBLE
);
1499 hrtimer_start_expires(&t
->timer
, mode
);
1500 if (!hrtimer_active(&t
->timer
))
1503 if (likely(t
->task
))
1504 freezable_schedule();
1506 hrtimer_cancel(&t
->timer
);
1507 mode
= HRTIMER_MODE_ABS
;
1509 } while (t
->task
&& !signal_pending(current
));
1511 __set_current_state(TASK_RUNNING
);
1513 return t
->task
== NULL
;
1516 static int update_rmtp(struct hrtimer
*timer
, struct timespec __user
*rmtp
)
1518 struct timespec rmt
;
1521 rem
= hrtimer_expires_remaining(timer
);
1524 rmt
= ktime_to_timespec(rem
);
1526 if (copy_to_user(rmtp
, &rmt
, sizeof(*rmtp
)))
1532 long __sched
hrtimer_nanosleep_restart(struct restart_block
*restart
)
1534 struct hrtimer_sleeper t
;
1535 struct timespec __user
*rmtp
;
1538 hrtimer_init_on_stack(&t
.timer
, restart
->nanosleep
.clockid
,
1540 hrtimer_set_expires_tv64(&t
.timer
, restart
->nanosleep
.expires
);
1542 if (do_nanosleep(&t
, HRTIMER_MODE_ABS
))
1545 rmtp
= restart
->nanosleep
.rmtp
;
1547 ret
= update_rmtp(&t
.timer
, rmtp
);
1552 /* The other values in restart are already filled in */
1553 ret
= -ERESTART_RESTARTBLOCK
;
1555 destroy_hrtimer_on_stack(&t
.timer
);
1559 long hrtimer_nanosleep(struct timespec
*rqtp
, struct timespec __user
*rmtp
,
1560 const enum hrtimer_mode mode
, const clockid_t clockid
)
1562 struct restart_block
*restart
;
1563 struct hrtimer_sleeper t
;
1565 unsigned long slack
;
1567 slack
= current
->timer_slack_ns
;
1568 if (dl_task(current
) || rt_task(current
))
1571 hrtimer_init_on_stack(&t
.timer
, clockid
, mode
);
1572 hrtimer_set_expires_range_ns(&t
.timer
, timespec_to_ktime(*rqtp
), slack
);
1573 if (do_nanosleep(&t
, mode
))
1576 /* Absolute timers do not update the rmtp value and restart: */
1577 if (mode
== HRTIMER_MODE_ABS
) {
1578 ret
= -ERESTARTNOHAND
;
1583 ret
= update_rmtp(&t
.timer
, rmtp
);
1588 restart
= ¤t
->restart_block
;
1589 restart
->fn
= hrtimer_nanosleep_restart
;
1590 restart
->nanosleep
.clockid
= t
.timer
.base
->clockid
;
1591 restart
->nanosleep
.rmtp
= rmtp
;
1592 restart
->nanosleep
.expires
= hrtimer_get_expires_tv64(&t
.timer
);
1594 ret
= -ERESTART_RESTARTBLOCK
;
1596 destroy_hrtimer_on_stack(&t
.timer
);
1600 SYSCALL_DEFINE2(nanosleep
, struct timespec __user
*, rqtp
,
1601 struct timespec __user
*, rmtp
)
1605 if (copy_from_user(&tu
, rqtp
, sizeof(tu
)))
1608 if (!timespec_valid(&tu
))
1611 return hrtimer_nanosleep(&tu
, rmtp
, HRTIMER_MODE_REL
, CLOCK_MONOTONIC
);
1615 * Functions related to boot-time initialization:
1617 static void init_hrtimers_cpu(int cpu
)
1619 struct hrtimer_cpu_base
*cpu_base
= &per_cpu(hrtimer_bases
, cpu
);
1622 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1623 cpu_base
->clock_base
[i
].cpu_base
= cpu_base
;
1624 timerqueue_init_head(&cpu_base
->clock_base
[i
].active
);
1627 cpu_base
->cpu
= cpu
;
1628 hrtimer_init_hres(cpu_base
);
1631 #ifdef CONFIG_HOTPLUG_CPU
1633 static void migrate_hrtimer_list(struct hrtimer_clock_base
*old_base
,
1634 struct hrtimer_clock_base
*new_base
)
1636 struct hrtimer
*timer
;
1637 struct timerqueue_node
*node
;
1639 while ((node
= timerqueue_getnext(&old_base
->active
))) {
1640 timer
= container_of(node
, struct hrtimer
, node
);
1641 BUG_ON(hrtimer_callback_running(timer
));
1642 debug_deactivate(timer
);
1645 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
1646 * timer could be seen as !active and just vanish away
1647 * under us on another CPU
1649 __remove_hrtimer(timer
, old_base
, HRTIMER_STATE_MIGRATE
, 0);
1650 timer
->base
= new_base
;
1652 * Enqueue the timers on the new cpu. This does not
1653 * reprogram the event device in case the timer
1654 * expires before the earliest on this CPU, but we run
1655 * hrtimer_interrupt after we migrated everything to
1656 * sort out already expired timers and reprogram the
1659 enqueue_hrtimer(timer
, new_base
);
1661 /* Clear the migration state bit */
1662 timer
->state
&= ~HRTIMER_STATE_MIGRATE
;
1666 static void migrate_hrtimers(int scpu
)
1668 struct hrtimer_cpu_base
*old_base
, *new_base
;
1671 BUG_ON(cpu_online(scpu
));
1672 tick_cancel_sched_timer(scpu
);
1674 local_irq_disable();
1675 old_base
= &per_cpu(hrtimer_bases
, scpu
);
1676 new_base
= this_cpu_ptr(&hrtimer_bases
);
1678 * The caller is globally serialized and nobody else
1679 * takes two locks at once, deadlock is not possible.
1681 raw_spin_lock(&new_base
->lock
);
1682 raw_spin_lock_nested(&old_base
->lock
, SINGLE_DEPTH_NESTING
);
1684 for (i
= 0; i
< HRTIMER_MAX_CLOCK_BASES
; i
++) {
1685 migrate_hrtimer_list(&old_base
->clock_base
[i
],
1686 &new_base
->clock_base
[i
]);
1689 raw_spin_unlock(&old_base
->lock
);
1690 raw_spin_unlock(&new_base
->lock
);
1692 /* Check, if we got expired work to do */
1693 __hrtimer_peek_ahead_timers();
1697 #endif /* CONFIG_HOTPLUG_CPU */
1699 static int hrtimer_cpu_notify(struct notifier_block
*self
,
1700 unsigned long action
, void *hcpu
)
1702 int scpu
= (long)hcpu
;
1706 case CPU_UP_PREPARE
:
1707 case CPU_UP_PREPARE_FROZEN
:
1708 init_hrtimers_cpu(scpu
);
1711 #ifdef CONFIG_HOTPLUG_CPU
1713 case CPU_DEAD_FROZEN
:
1714 migrate_hrtimers(scpu
);
1725 static struct notifier_block hrtimers_nb
= {
1726 .notifier_call
= hrtimer_cpu_notify
,
1729 void __init
hrtimers_init(void)
1731 hrtimer_cpu_notify(&hrtimers_nb
, (unsigned long)CPU_UP_PREPARE
,
1732 (void *)(long)smp_processor_id());
1733 register_cpu_notifier(&hrtimers_nb
);
1734 #ifdef CONFIG_HIGH_RES_TIMERS
1735 open_softirq(HRTIMER_SOFTIRQ
, run_hrtimer_softirq
);
1740 * schedule_hrtimeout_range_clock - sleep until timeout
1741 * @expires: timeout value (ktime_t)
1742 * @delta: slack in expires timeout (ktime_t)
1743 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1744 * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1747 schedule_hrtimeout_range_clock(ktime_t
*expires
, unsigned long delta
,
1748 const enum hrtimer_mode mode
, int clock
)
1750 struct hrtimer_sleeper t
;
1753 * Optimize when a zero timeout value is given. It does not
1754 * matter whether this is an absolute or a relative time.
1756 if (expires
&& !expires
->tv64
) {
1757 __set_current_state(TASK_RUNNING
);
1762 * A NULL parameter means "infinite"
1769 hrtimer_init_on_stack(&t
.timer
, clock
, mode
);
1770 hrtimer_set_expires_range_ns(&t
.timer
, *expires
, delta
);
1772 hrtimer_init_sleeper(&t
, current
);
1774 hrtimer_start_expires(&t
.timer
, mode
);
1775 if (!hrtimer_active(&t
.timer
))
1781 hrtimer_cancel(&t
.timer
);
1782 destroy_hrtimer_on_stack(&t
.timer
);
1784 __set_current_state(TASK_RUNNING
);
1786 return !t
.task
? 0 : -EINTR
;
1790 * schedule_hrtimeout_range - sleep until timeout
1791 * @expires: timeout value (ktime_t)
1792 * @delta: slack in expires timeout (ktime_t)
1793 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1795 * Make the current task sleep until the given expiry time has
1796 * elapsed. The routine will return immediately unless
1797 * the current task state has been set (see set_current_state()).
1799 * The @delta argument gives the kernel the freedom to schedule the
1800 * actual wakeup to a time that is both power and performance friendly.
1801 * The kernel give the normal best effort behavior for "@expires+@delta",
1802 * but may decide to fire the timer earlier, but no earlier than @expires.
1804 * You can set the task state as follows -
1806 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1807 * pass before the routine returns.
1809 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1810 * delivered to the current task.
1812 * The current task state is guaranteed to be TASK_RUNNING when this
1815 * Returns 0 when the timer has expired otherwise -EINTR
1817 int __sched
schedule_hrtimeout_range(ktime_t
*expires
, unsigned long delta
,
1818 const enum hrtimer_mode mode
)
1820 return schedule_hrtimeout_range_clock(expires
, delta
, mode
,
1823 EXPORT_SYMBOL_GPL(schedule_hrtimeout_range
);
1826 * schedule_hrtimeout - sleep until timeout
1827 * @expires: timeout value (ktime_t)
1828 * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1830 * Make the current task sleep until the given expiry time has
1831 * elapsed. The routine will return immediately unless
1832 * the current task state has been set (see set_current_state()).
1834 * You can set the task state as follows -
1836 * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1837 * pass before the routine returns.
1839 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1840 * delivered to the current task.
1842 * The current task state is guaranteed to be TASK_RUNNING when this
1845 * Returns 0 when the timer has expired otherwise -EINTR
1847 int __sched
schedule_hrtimeout(ktime_t
*expires
,
1848 const enum hrtimer_mode mode
)
1850 return schedule_hrtimeout_range(expires
, 0, mode
);
1852 EXPORT_SYMBOL_GPL(schedule_hrtimeout
);