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>
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#include <linux/tick.h>
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#include <linux/seq_file.h>
44
#include <linux/err.h>
45
#include <linux/debugobjects.h>
46
#include <linux/sched.h>
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#include <linux/timer.h>
49
#include <asm/uaccess.h>
51
#include <trace/events/timer.h>
56
* There are more clockids then hrtimer bases. Thus, we index
57
* into the timer bases by the hrtimer_base_type enum. When trying
58
* to reach a base using a clockid, hrtimer_clockid_to_base()
59
* is used to convert from clockid to the proper hrtimer_base_type.
61
DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
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.index = HRTIMER_BASE_MONOTONIC,
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.clockid = CLOCK_MONOTONIC,
69
.get_time = &ktime_get,
70
.resolution = KTIME_LOW_RES,
73
.index = HRTIMER_BASE_REALTIME,
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.clockid = CLOCK_REALTIME,
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.get_time = &ktime_get_real,
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.resolution = KTIME_LOW_RES,
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.index = HRTIMER_BASE_BOOTTIME,
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.clockid = CLOCK_BOOTTIME,
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.get_time = &ktime_get_boottime,
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.resolution = KTIME_LOW_RES,
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static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = {
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[CLOCK_REALTIME] = HRTIMER_BASE_REALTIME,
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[CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC,
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[CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME,
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static inline int hrtimer_clockid_to_base(clockid_t clock_id)
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return hrtimer_clock_to_base_table[clock_id];
100
* Get the coarse grained time at the softirq based on xtime and
103
static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
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ktime_t xtim, mono, boot;
106
struct timespec xts, tom, slp;
108
get_xtime_and_monotonic_and_sleep_offset(&xts, &tom, &slp);
110
xtim = timespec_to_ktime(xts);
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mono = ktime_add(xtim, timespec_to_ktime(tom));
112
boot = ktime_add(mono, timespec_to_ktime(slp));
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base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim;
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base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono;
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base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot;
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* Functions and macros which are different for UP/SMP systems are kept in a
125
* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
126
* means that all timers which are tied to this base via timer->base are
127
* locked, and the base itself is locked too.
129
* So __run_timers/migrate_timers can safely modify all timers which could
130
* be found on the lists/queues.
132
* When the timer's base is locked, and the timer removed from list, it is
133
* possible to set timer->base = NULL and drop the lock: the timer remains
137
struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
138
unsigned long *flags)
140
struct hrtimer_clock_base *base;
144
if (likely(base != NULL)) {
145
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
146
if (likely(base == timer->base))
148
/* The timer has migrated to another CPU: */
149
raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
157
* Get the preferred target CPU for NOHZ
159
static int hrtimer_get_target(int this_cpu, int pinned)
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if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
163
return get_nohz_timer_target();
169
* With HIGHRES=y we do not migrate the timer when it is expiring
170
* before the next event on the target cpu because we cannot reprogram
171
* the target cpu hardware and we would cause it to fire late.
173
* Called with cpu_base->lock of target cpu held.
176
hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
178
#ifdef CONFIG_HIGH_RES_TIMERS
181
if (!new_base->cpu_base->hres_active)
184
expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
185
return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
192
* Switch the timer base to the current CPU when possible.
194
static inline struct hrtimer_clock_base *
195
switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
198
struct hrtimer_clock_base *new_base;
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struct hrtimer_cpu_base *new_cpu_base;
200
int this_cpu = smp_processor_id();
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int cpu = hrtimer_get_target(this_cpu, pinned);
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int basenum = base->index;
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new_cpu_base = &per_cpu(hrtimer_bases, cpu);
206
new_base = &new_cpu_base->clock_base[basenum];
208
if (base != new_base) {
210
* We are trying to move timer to new_base.
211
* However we can't change timer's base while it is running,
212
* so we keep it on the same CPU. No hassle vs. reprogramming
213
* the event source in the high resolution case. The softirq
214
* code will take care of this when the timer function has
215
* completed. There is no conflict as we hold the lock until
216
* the timer is enqueued.
218
if (unlikely(hrtimer_callback_running(timer)))
221
/* See the comment in lock_timer_base() */
223
raw_spin_unlock(&base->cpu_base->lock);
224
raw_spin_lock(&new_base->cpu_base->lock);
226
if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
228
raw_spin_unlock(&new_base->cpu_base->lock);
229
raw_spin_lock(&base->cpu_base->lock);
233
timer->base = new_base;
238
#else /* CONFIG_SMP */
240
static inline struct hrtimer_clock_base *
241
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
243
struct hrtimer_clock_base *base = timer->base;
245
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
250
# define switch_hrtimer_base(t, b, p) (b)
252
#endif /* !CONFIG_SMP */
255
* Functions for the union type storage format of ktime_t which are
256
* too large for inlining:
258
#if BITS_PER_LONG < 64
259
# ifndef CONFIG_KTIME_SCALAR
261
* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
263
* @nsec: the scalar nsec value to add
265
* Returns the sum of kt and nsec in ktime_t format
267
ktime_t ktime_add_ns(const ktime_t kt, u64 nsec)
271
if (likely(nsec < NSEC_PER_SEC)) {
274
unsigned long rem = do_div(nsec, NSEC_PER_SEC);
276
tmp = ktime_set((long)nsec, rem);
279
return ktime_add(kt, tmp);
282
EXPORT_SYMBOL_GPL(ktime_add_ns);
285
* ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
287
* @nsec: the scalar nsec value to subtract
289
* Returns the subtraction of @nsec from @kt in ktime_t format
291
ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
295
if (likely(nsec < NSEC_PER_SEC)) {
298
unsigned long rem = do_div(nsec, NSEC_PER_SEC);
300
tmp = ktime_set((long)nsec, rem);
303
return ktime_sub(kt, tmp);
306
EXPORT_SYMBOL_GPL(ktime_sub_ns);
307
# endif /* !CONFIG_KTIME_SCALAR */
310
* Divide a ktime value by a nanosecond value
312
u64 ktime_divns(const ktime_t kt, s64 div)
317
dclc = ktime_to_ns(kt);
318
/* Make sure the divisor is less than 2^32: */
324
do_div(dclc, (unsigned long) div);
328
#endif /* BITS_PER_LONG >= 64 */
331
* Add two ktime values and do a safety check for overflow:
333
ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
335
ktime_t res = ktime_add(lhs, rhs);
338
* We use KTIME_SEC_MAX here, the maximum timeout which we can
339
* return to user space in a timespec:
341
if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
342
res = ktime_set(KTIME_SEC_MAX, 0);
347
EXPORT_SYMBOL_GPL(ktime_add_safe);
349
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
351
static struct debug_obj_descr hrtimer_debug_descr;
353
static void *hrtimer_debug_hint(void *addr)
355
return ((struct hrtimer *) addr)->function;
359
* fixup_init is called when:
360
* - an active object is initialized
362
static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
364
struct hrtimer *timer = addr;
367
case ODEBUG_STATE_ACTIVE:
368
hrtimer_cancel(timer);
369
debug_object_init(timer, &hrtimer_debug_descr);
377
* fixup_activate is called when:
378
* - an active object is activated
379
* - an unknown object is activated (might be a statically initialized object)
381
static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
385
case ODEBUG_STATE_NOTAVAILABLE:
389
case ODEBUG_STATE_ACTIVE:
398
* fixup_free is called when:
399
* - an active object is freed
401
static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
403
struct hrtimer *timer = addr;
406
case ODEBUG_STATE_ACTIVE:
407
hrtimer_cancel(timer);
408
debug_object_free(timer, &hrtimer_debug_descr);
415
static struct debug_obj_descr hrtimer_debug_descr = {
417
.debug_hint = hrtimer_debug_hint,
418
.fixup_init = hrtimer_fixup_init,
419
.fixup_activate = hrtimer_fixup_activate,
420
.fixup_free = hrtimer_fixup_free,
423
static inline void debug_hrtimer_init(struct hrtimer *timer)
425
debug_object_init(timer, &hrtimer_debug_descr);
428
static inline void debug_hrtimer_activate(struct hrtimer *timer)
430
debug_object_activate(timer, &hrtimer_debug_descr);
433
static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
435
debug_object_deactivate(timer, &hrtimer_debug_descr);
438
static inline void debug_hrtimer_free(struct hrtimer *timer)
440
debug_object_free(timer, &hrtimer_debug_descr);
443
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
444
enum hrtimer_mode mode);
446
void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
447
enum hrtimer_mode mode)
449
debug_object_init_on_stack(timer, &hrtimer_debug_descr);
450
__hrtimer_init(timer, clock_id, mode);
452
EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
454
void destroy_hrtimer_on_stack(struct hrtimer *timer)
456
debug_object_free(timer, &hrtimer_debug_descr);
460
static inline void debug_hrtimer_init(struct hrtimer *timer) { }
461
static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
462
static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
466
debug_init(struct hrtimer *timer, clockid_t clockid,
467
enum hrtimer_mode mode)
469
debug_hrtimer_init(timer);
470
trace_hrtimer_init(timer, clockid, mode);
473
static inline void debug_activate(struct hrtimer *timer)
475
debug_hrtimer_activate(timer);
476
trace_hrtimer_start(timer);
479
static inline void debug_deactivate(struct hrtimer *timer)
481
debug_hrtimer_deactivate(timer);
482
trace_hrtimer_cancel(timer);
485
/* High resolution timer related functions */
486
#ifdef CONFIG_HIGH_RES_TIMERS
489
* High resolution timer enabled ?
491
static int hrtimer_hres_enabled __read_mostly = 1;
494
* Enable / Disable high resolution mode
496
static int __init setup_hrtimer_hres(char *str)
498
if (!strcmp(str, "off"))
499
hrtimer_hres_enabled = 0;
500
else if (!strcmp(str, "on"))
501
hrtimer_hres_enabled = 1;
507
__setup("highres=", setup_hrtimer_hres);
510
* hrtimer_high_res_enabled - query, if the highres mode is enabled
512
static inline int hrtimer_is_hres_enabled(void)
514
return hrtimer_hres_enabled;
518
* Is the high resolution mode active ?
520
static inline int hrtimer_hres_active(void)
522
return __this_cpu_read(hrtimer_bases.hres_active);
526
* Reprogram the event source with checking both queues for the
528
* Called with interrupts disabled and base->lock held
531
hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
534
struct hrtimer_clock_base *base = cpu_base->clock_base;
535
ktime_t expires, expires_next;
537
expires_next.tv64 = KTIME_MAX;
539
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
540
struct hrtimer *timer;
541
struct timerqueue_node *next;
543
next = timerqueue_getnext(&base->active);
546
timer = container_of(next, struct hrtimer, node);
548
expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
550
* clock_was_set() has changed base->offset so the
551
* result might be negative. Fix it up to prevent a
552
* false positive in clockevents_program_event()
554
if (expires.tv64 < 0)
556
if (expires.tv64 < expires_next.tv64)
557
expires_next = expires;
560
if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
563
cpu_base->expires_next.tv64 = expires_next.tv64;
565
if (cpu_base->expires_next.tv64 != KTIME_MAX)
566
tick_program_event(cpu_base->expires_next, 1);
570
* Shared reprogramming for clock_realtime and clock_monotonic
572
* When a timer is enqueued and expires earlier than the already enqueued
573
* timers, we have to check, whether it expires earlier than the timer for
574
* which the clock event device was armed.
576
* Called with interrupts disabled and base->cpu_base.lock held
578
static int hrtimer_reprogram(struct hrtimer *timer,
579
struct hrtimer_clock_base *base)
581
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
582
ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
585
WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
588
* When the callback is running, we do not reprogram the clock event
589
* device. The timer callback is either running on a different CPU or
590
* the callback is executed in the hrtimer_interrupt context. The
591
* reprogramming is handled either by the softirq, which called the
592
* callback or at the end of the hrtimer_interrupt.
594
if (hrtimer_callback_running(timer))
598
* CLOCK_REALTIME timer might be requested with an absolute
599
* expiry time which is less than base->offset. Nothing wrong
600
* about that, just avoid to call into the tick code, which
601
* has now objections against negative expiry values.
603
if (expires.tv64 < 0)
606
if (expires.tv64 >= cpu_base->expires_next.tv64)
610
* If a hang was detected in the last timer interrupt then we
611
* do not schedule a timer which is earlier than the expiry
612
* which we enforced in the hang detection. We want the system
615
if (cpu_base->hang_detected)
619
* Clockevents returns -ETIME, when the event was in the past.
621
res = tick_program_event(expires, 0);
622
if (!IS_ERR_VALUE(res))
623
cpu_base->expires_next = expires;
628
* Initialize the high resolution related parts of cpu_base
630
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
632
base->expires_next.tv64 = KTIME_MAX;
633
base->hres_active = 0;
637
* When High resolution timers are active, try to reprogram. Note, that in case
638
* the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
639
* check happens. The timer gets enqueued into the rbtree. The reprogramming
640
* and expiry check is done in the hrtimer_interrupt or in the softirq.
642
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
643
struct hrtimer_clock_base *base,
646
if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
648
raw_spin_unlock(&base->cpu_base->lock);
649
raise_softirq_irqoff(HRTIMER_SOFTIRQ);
650
raw_spin_lock(&base->cpu_base->lock);
652
__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
661
* Retrigger next event is called after clock was set
663
* Called with interrupts disabled via on_each_cpu()
665
static void retrigger_next_event(void *arg)
667
struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
668
struct timespec realtime_offset, xtim, wtm, sleep;
670
if (!hrtimer_hres_active())
673
/* Optimized out for !HIGH_RES */
674
get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep);
675
set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
677
/* Adjust CLOCK_REALTIME offset */
678
raw_spin_lock(&base->lock);
679
base->clock_base[HRTIMER_BASE_REALTIME].offset =
680
timespec_to_ktime(realtime_offset);
681
base->clock_base[HRTIMER_BASE_BOOTTIME].offset =
682
timespec_to_ktime(sleep);
684
hrtimer_force_reprogram(base, 0);
685
raw_spin_unlock(&base->lock);
689
* Switch to high resolution mode
691
static int hrtimer_switch_to_hres(void)
693
int i, cpu = smp_processor_id();
694
struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
697
if (base->hres_active)
700
local_irq_save(flags);
702
if (tick_init_highres()) {
703
local_irq_restore(flags);
704
printk(KERN_WARNING "Could not switch to high resolution "
705
"mode on CPU %d\n", cpu);
708
base->hres_active = 1;
709
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
710
base->clock_base[i].resolution = KTIME_HIGH_RES;
712
tick_setup_sched_timer();
714
/* "Retrigger" the interrupt to get things going */
715
retrigger_next_event(NULL);
716
local_irq_restore(flags);
722
static inline int hrtimer_hres_active(void) { return 0; }
723
static inline int hrtimer_is_hres_enabled(void) { return 0; }
724
static inline int hrtimer_switch_to_hres(void) { return 0; }
726
hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
727
static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
728
struct hrtimer_clock_base *base,
733
static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
734
static inline void retrigger_next_event(void *arg) { }
736
#endif /* CONFIG_HIGH_RES_TIMERS */
739
* Clock realtime was set
741
* Change the offset of the realtime clock vs. the monotonic
744
* We might have to reprogram the high resolution timer interrupt. On
745
* SMP we call the architecture specific code to retrigger _all_ high
746
* resolution timer interrupts. On UP we just disable interrupts and
747
* call the high resolution interrupt code.
749
void clock_was_set(void)
751
#ifdef CONFIG_HIGH_RES_TIMERS
752
/* Retrigger the CPU local events everywhere */
753
on_each_cpu(retrigger_next_event, NULL, 1);
755
timerfd_clock_was_set();
759
* During resume we might have to reprogram the high resolution timer
760
* interrupt (on the local CPU):
762
void hrtimers_resume(void)
764
WARN_ONCE(!irqs_disabled(),
765
KERN_INFO "hrtimers_resume() called with IRQs enabled!");
767
retrigger_next_event(NULL);
768
timerfd_clock_was_set();
771
static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
773
#ifdef CONFIG_TIMER_STATS
774
if (timer->start_site)
776
timer->start_site = __builtin_return_address(0);
777
memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
778
timer->start_pid = current->pid;
782
static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
784
#ifdef CONFIG_TIMER_STATS
785
timer->start_site = NULL;
789
static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
791
#ifdef CONFIG_TIMER_STATS
792
if (likely(!timer_stats_active))
794
timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
795
timer->function, timer->start_comm, 0);
800
* Counterpart to lock_hrtimer_base above:
803
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
805
raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
809
* hrtimer_forward - forward the timer expiry
810
* @timer: hrtimer to forward
811
* @now: forward past this time
812
* @interval: the interval to forward
814
* Forward the timer expiry so it will expire in the future.
815
* Returns the number of overruns.
817
u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
822
delta = ktime_sub(now, hrtimer_get_expires(timer));
827
if (interval.tv64 < timer->base->resolution.tv64)
828
interval.tv64 = timer->base->resolution.tv64;
830
if (unlikely(delta.tv64 >= interval.tv64)) {
831
s64 incr = ktime_to_ns(interval);
833
orun = ktime_divns(delta, incr);
834
hrtimer_add_expires_ns(timer, incr * orun);
835
if (hrtimer_get_expires_tv64(timer) > now.tv64)
838
* This (and the ktime_add() below) is the
839
* correction for exact:
843
hrtimer_add_expires(timer, interval);
847
EXPORT_SYMBOL_GPL(hrtimer_forward);
850
* enqueue_hrtimer - internal function to (re)start a timer
852
* The timer is inserted in expiry order. Insertion into the
853
* red black tree is O(log(n)). Must hold the base lock.
855
* Returns 1 when the new timer is the leftmost timer in the tree.
857
static int enqueue_hrtimer(struct hrtimer *timer,
858
struct hrtimer_clock_base *base)
860
debug_activate(timer);
862
timerqueue_add(&base->active, &timer->node);
863
base->cpu_base->active_bases |= 1 << base->index;
866
* HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
867
* state of a possibly running callback.
869
timer->state |= HRTIMER_STATE_ENQUEUED;
871
return (&timer->node == base->active.next);
875
* __remove_hrtimer - internal function to remove a timer
877
* Caller must hold the base lock.
879
* High resolution timer mode reprograms the clock event device when the
880
* timer is the one which expires next. The caller can disable this by setting
881
* reprogram to zero. This is useful, when the context does a reprogramming
882
* anyway (e.g. timer interrupt)
884
static void __remove_hrtimer(struct hrtimer *timer,
885
struct hrtimer_clock_base *base,
886
unsigned long newstate, int reprogram)
888
struct timerqueue_node *next_timer;
889
if (!(timer->state & HRTIMER_STATE_ENQUEUED))
892
next_timer = timerqueue_getnext(&base->active);
893
timerqueue_del(&base->active, &timer->node);
894
if (&timer->node == next_timer) {
895
#ifdef CONFIG_HIGH_RES_TIMERS
896
/* Reprogram the clock event device. if enabled */
897
if (reprogram && hrtimer_hres_active()) {
900
expires = ktime_sub(hrtimer_get_expires(timer),
902
if (base->cpu_base->expires_next.tv64 == expires.tv64)
903
hrtimer_force_reprogram(base->cpu_base, 1);
907
if (!timerqueue_getnext(&base->active))
908
base->cpu_base->active_bases &= ~(1 << base->index);
910
timer->state = newstate;
914
* remove hrtimer, called with base lock held
917
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
919
if (hrtimer_is_queued(timer)) {
924
* Remove the timer and force reprogramming when high
925
* resolution mode is active and the timer is on the current
926
* CPU. If we remove a timer on another CPU, reprogramming is
927
* skipped. The interrupt event on this CPU is fired and
928
* reprogramming happens in the interrupt handler. This is a
929
* rare case and less expensive than a smp call.
931
debug_deactivate(timer);
932
timer_stats_hrtimer_clear_start_info(timer);
933
reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
935
* We must preserve the CALLBACK state flag here,
936
* otherwise we could move the timer base in
937
* switch_hrtimer_base.
939
state = timer->state & HRTIMER_STATE_CALLBACK;
940
__remove_hrtimer(timer, base, state, reprogram);
946
int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
947
unsigned long delta_ns, const enum hrtimer_mode mode,
950
struct hrtimer_clock_base *base, *new_base;
954
base = lock_hrtimer_base(timer, &flags);
956
/* Remove an active timer from the queue: */
957
ret = remove_hrtimer(timer, base);
959
/* Switch the timer base, if necessary: */
960
new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
962
if (mode & HRTIMER_MODE_REL) {
963
tim = ktime_add_safe(tim, new_base->get_time());
965
* CONFIG_TIME_LOW_RES is a temporary way for architectures
966
* to signal that they simply return xtime in
967
* do_gettimeoffset(). In this case we want to round up by
968
* resolution when starting a relative timer, to avoid short
969
* timeouts. This will go away with the GTOD framework.
971
#ifdef CONFIG_TIME_LOW_RES
972
tim = ktime_add_safe(tim, base->resolution);
976
hrtimer_set_expires_range_ns(timer, tim, delta_ns);
978
timer_stats_hrtimer_set_start_info(timer);
980
leftmost = enqueue_hrtimer(timer, new_base);
983
* Only allow reprogramming if the new base is on this CPU.
984
* (it might still be on another CPU if the timer was pending)
986
* XXX send_remote_softirq() ?
988
if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
989
hrtimer_enqueue_reprogram(timer, new_base, wakeup);
991
unlock_hrtimer_base(timer, &flags);
997
* hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
998
* @timer: the timer to be added
1000
* @delta_ns: "slack" range for the timer
1001
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1005
* 1 when the timer was active
1007
int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
1008
unsigned long delta_ns, const enum hrtimer_mode mode)
1010
return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
1012
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
1015
* hrtimer_start - (re)start an hrtimer on the current CPU
1016
* @timer: the timer to be added
1018
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
1022
* 1 when the timer was active
1025
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
1027
return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
1029
EXPORT_SYMBOL_GPL(hrtimer_start);
1033
* hrtimer_try_to_cancel - try to deactivate a timer
1034
* @timer: hrtimer to stop
1037
* 0 when the timer was not active
1038
* 1 when the timer was active
1039
* -1 when the timer is currently excuting the callback function and
1042
int hrtimer_try_to_cancel(struct hrtimer *timer)
1044
struct hrtimer_clock_base *base;
1045
unsigned long flags;
1048
base = lock_hrtimer_base(timer, &flags);
1050
if (!hrtimer_callback_running(timer))
1051
ret = remove_hrtimer(timer, base);
1053
unlock_hrtimer_base(timer, &flags);
1058
EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
1061
* hrtimer_cancel - cancel a timer and wait for the handler to finish.
1062
* @timer: the timer to be cancelled
1065
* 0 when the timer was not active
1066
* 1 when the timer was active
1068
int hrtimer_cancel(struct hrtimer *timer)
1071
int ret = hrtimer_try_to_cancel(timer);
1078
EXPORT_SYMBOL_GPL(hrtimer_cancel);
1081
* hrtimer_get_remaining - get remaining time for the timer
1082
* @timer: the timer to read
1084
ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
1086
unsigned long flags;
1089
lock_hrtimer_base(timer, &flags);
1090
rem = hrtimer_expires_remaining(timer);
1091
unlock_hrtimer_base(timer, &flags);
1095
EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
1099
* hrtimer_get_next_event - get the time until next expiry event
1101
* Returns the delta to the next expiry event or KTIME_MAX if no timer
1104
ktime_t hrtimer_get_next_event(void)
1106
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1107
struct hrtimer_clock_base *base = cpu_base->clock_base;
1108
ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
1109
unsigned long flags;
1112
raw_spin_lock_irqsave(&cpu_base->lock, flags);
1114
if (!hrtimer_hres_active()) {
1115
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
1116
struct hrtimer *timer;
1117
struct timerqueue_node *next;
1119
next = timerqueue_getnext(&base->active);
1123
timer = container_of(next, struct hrtimer, node);
1124
delta.tv64 = hrtimer_get_expires_tv64(timer);
1125
delta = ktime_sub(delta, base->get_time());
1126
if (delta.tv64 < mindelta.tv64)
1127
mindelta.tv64 = delta.tv64;
1131
raw_spin_unlock_irqrestore(&cpu_base->lock, flags);
1133
if (mindelta.tv64 < 0)
1139
static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1140
enum hrtimer_mode mode)
1142
struct hrtimer_cpu_base *cpu_base;
1145
memset(timer, 0, sizeof(struct hrtimer));
1147
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1149
if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
1150
clock_id = CLOCK_MONOTONIC;
1152
base = hrtimer_clockid_to_base(clock_id);
1153
timer->base = &cpu_base->clock_base[base];
1154
timerqueue_init(&timer->node);
1156
#ifdef CONFIG_TIMER_STATS
1157
timer->start_site = NULL;
1158
timer->start_pid = -1;
1159
memset(timer->start_comm, 0, TASK_COMM_LEN);
1164
* hrtimer_init - initialize a timer to the given clock
1165
* @timer: the timer to be initialized
1166
* @clock_id: the clock to be used
1167
* @mode: timer mode abs/rel
1169
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
1170
enum hrtimer_mode mode)
1172
debug_init(timer, clock_id, mode);
1173
__hrtimer_init(timer, clock_id, mode);
1175
EXPORT_SYMBOL_GPL(hrtimer_init);
1178
* hrtimer_get_res - get the timer resolution for a clock
1179
* @which_clock: which clock to query
1180
* @tp: pointer to timespec variable to store the resolution
1182
* Store the resolution of the clock selected by @which_clock in the
1183
* variable pointed to by @tp.
1185
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
1187
struct hrtimer_cpu_base *cpu_base;
1188
int base = hrtimer_clockid_to_base(which_clock);
1190
cpu_base = &__raw_get_cpu_var(hrtimer_bases);
1191
*tp = ktime_to_timespec(cpu_base->clock_base[base].resolution);
1195
EXPORT_SYMBOL_GPL(hrtimer_get_res);
1197
static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
1199
struct hrtimer_clock_base *base = timer->base;
1200
struct hrtimer_cpu_base *cpu_base = base->cpu_base;
1201
enum hrtimer_restart (*fn)(struct hrtimer *);
1204
WARN_ON(!irqs_disabled());
1206
debug_deactivate(timer);
1207
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
1208
timer_stats_account_hrtimer(timer);
1209
fn = timer->function;
1212
* Because we run timers from hardirq context, there is no chance
1213
* they get migrated to another cpu, therefore its safe to unlock
1216
raw_spin_unlock(&cpu_base->lock);
1217
trace_hrtimer_expire_entry(timer, now);
1218
restart = fn(timer);
1219
trace_hrtimer_expire_exit(timer);
1220
raw_spin_lock(&cpu_base->lock);
1223
* Note: We clear the CALLBACK bit after enqueue_hrtimer and
1224
* we do not reprogramm the event hardware. Happens either in
1225
* hrtimer_start_range_ns() or in hrtimer_interrupt()
1227
if (restart != HRTIMER_NORESTART) {
1228
BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
1229
enqueue_hrtimer(timer, base);
1232
WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));
1234
timer->state &= ~HRTIMER_STATE_CALLBACK;
1237
#ifdef CONFIG_HIGH_RES_TIMERS
1240
* High resolution timer interrupt
1241
* Called with interrupts disabled
1243
void hrtimer_interrupt(struct clock_event_device *dev)
1245
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
1246
ktime_t expires_next, now, entry_time, delta;
1249
BUG_ON(!cpu_base->hres_active);
1250
cpu_base->nr_events++;
1251
dev->next_event.tv64 = KTIME_MAX;
1253
entry_time = now = ktime_get();
1255
expires_next.tv64 = KTIME_MAX;
1257
raw_spin_lock(&cpu_base->lock);
1259
* We set expires_next to KTIME_MAX here with cpu_base->lock
1260
* held to prevent that a timer is enqueued in our queue via
1261
* the migration code. This does not affect enqueueing of
1262
* timers which run their callback and need to be requeued on
1265
cpu_base->expires_next.tv64 = KTIME_MAX;
1267
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1268
struct hrtimer_clock_base *base;
1269
struct timerqueue_node *node;
1272
if (!(cpu_base->active_bases & (1 << i)))
1275
base = cpu_base->clock_base + i;
1276
basenow = ktime_add(now, base->offset);
1278
while ((node = timerqueue_getnext(&base->active))) {
1279
struct hrtimer *timer;
1281
timer = container_of(node, struct hrtimer, node);
1284
* The immediate goal for using the softexpires is
1285
* minimizing wakeups, not running timers at the
1286
* earliest interrupt after their soft expiration.
1287
* This allows us to avoid using a Priority Search
1288
* Tree, which can answer a stabbing querry for
1289
* overlapping intervals and instead use the simple
1290
* BST we already have.
1291
* We don't add extra wakeups by delaying timers that
1292
* are right-of a not yet expired timer, because that
1293
* timer will have to trigger a wakeup anyway.
1296
if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
1299
expires = ktime_sub(hrtimer_get_expires(timer),
1301
if (expires.tv64 < expires_next.tv64)
1302
expires_next = expires;
1306
__run_hrtimer(timer, &basenow);
1311
* Store the new expiry value so the migration code can verify
1314
cpu_base->expires_next = expires_next;
1315
raw_spin_unlock(&cpu_base->lock);
1317
/* Reprogramming necessary ? */
1318
if (expires_next.tv64 == KTIME_MAX ||
1319
!tick_program_event(expires_next, 0)) {
1320
cpu_base->hang_detected = 0;
1325
* The next timer was already expired due to:
1327
* - long lasting callbacks
1328
* - being scheduled away when running in a VM
1330
* We need to prevent that we loop forever in the hrtimer
1331
* interrupt routine. We give it 3 attempts to avoid
1332
* overreacting on some spurious event.
1335
cpu_base->nr_retries++;
1339
* Give the system a chance to do something else than looping
1340
* here. We stored the entry time, so we know exactly how long
1341
* we spent here. We schedule the next event this amount of
1344
cpu_base->nr_hangs++;
1345
cpu_base->hang_detected = 1;
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 = &__get_cpu_var(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 = &__get_cpu_var(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))
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 (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_thread_info()->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 __cpuinit init_hrtimers_cpu(int cpu)
1619
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
1622
raw_spin_lock_init(&cpu_base->lock);
1624
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1625
cpu_base->clock_base[i].cpu_base = cpu_base;
1626
timerqueue_init_head(&cpu_base->clock_base[i].active);
1629
hrtimer_init_hres(cpu_base);
1632
#ifdef CONFIG_HOTPLUG_CPU
1634
static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
1635
struct hrtimer_clock_base *new_base)
1637
struct hrtimer *timer;
1638
struct timerqueue_node *node;
1640
while ((node = timerqueue_getnext(&old_base->active))) {
1641
timer = container_of(node, struct hrtimer, node);
1642
BUG_ON(hrtimer_callback_running(timer));
1643
debug_deactivate(timer);
1646
* Mark it as STATE_MIGRATE not INACTIVE otherwise the
1647
* timer could be seen as !active and just vanish away
1648
* under us on another CPU
1650
__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
1651
timer->base = new_base;
1653
* Enqueue the timers on the new cpu. This does not
1654
* reprogram the event device in case the timer
1655
* expires before the earliest on this CPU, but we run
1656
* hrtimer_interrupt after we migrated everything to
1657
* sort out already expired timers and reprogram the
1660
enqueue_hrtimer(timer, new_base);
1662
/* Clear the migration state bit */
1663
timer->state &= ~HRTIMER_STATE_MIGRATE;
1667
static void migrate_hrtimers(int scpu)
1669
struct hrtimer_cpu_base *old_base, *new_base;
1672
BUG_ON(cpu_online(scpu));
1673
tick_cancel_sched_timer(scpu);
1675
local_irq_disable();
1676
old_base = &per_cpu(hrtimer_bases, scpu);
1677
new_base = &__get_cpu_var(hrtimer_bases);
1679
* The caller is globally serialized and nobody else
1680
* takes two locks at once, deadlock is not possible.
1682
raw_spin_lock(&new_base->lock);
1683
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1685
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
1686
migrate_hrtimer_list(&old_base->clock_base[i],
1687
&new_base->clock_base[i]);
1690
raw_spin_unlock(&old_base->lock);
1691
raw_spin_unlock(&new_base->lock);
1693
/* Check, if we got expired work to do */
1694
__hrtimer_peek_ahead_timers();
1698
#endif /* CONFIG_HOTPLUG_CPU */
1700
static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
1701
unsigned long action, void *hcpu)
1703
int scpu = (long)hcpu;
1707
case CPU_UP_PREPARE:
1708
case CPU_UP_PREPARE_FROZEN:
1709
init_hrtimers_cpu(scpu);
1712
#ifdef CONFIG_HOTPLUG_CPU
1714
case CPU_DYING_FROZEN:
1715
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
1718
case CPU_DEAD_FROZEN:
1720
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
1721
migrate_hrtimers(scpu);
1733
static struct notifier_block __cpuinitdata hrtimers_nb = {
1734
.notifier_call = hrtimer_cpu_notify,
1737
void __init hrtimers_init(void)
1739
hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
1740
(void *)(long)smp_processor_id());
1741
register_cpu_notifier(&hrtimers_nb);
1742
#ifdef CONFIG_HIGH_RES_TIMERS
1743
open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
1748
* schedule_hrtimeout_range_clock - sleep until timeout
1749
* @expires: timeout value (ktime_t)
1750
* @delta: slack in expires timeout (ktime_t)
1751
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1752
* @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME
1755
schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta,
1756
const enum hrtimer_mode mode, int clock)
1758
struct hrtimer_sleeper t;
1761
* Optimize when a zero timeout value is given. It does not
1762
* matter whether this is an absolute or a relative time.
1764
if (expires && !expires->tv64) {
1765
__set_current_state(TASK_RUNNING);
1770
* A NULL parameter means "infinite"
1774
__set_current_state(TASK_RUNNING);
1778
hrtimer_init_on_stack(&t.timer, clock, mode);
1779
hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
1781
hrtimer_init_sleeper(&t, current);
1783
hrtimer_start_expires(&t.timer, mode);
1784
if (!hrtimer_active(&t.timer))
1790
hrtimer_cancel(&t.timer);
1791
destroy_hrtimer_on_stack(&t.timer);
1793
__set_current_state(TASK_RUNNING);
1795
return !t.task ? 0 : -EINTR;
1799
* schedule_hrtimeout_range - sleep until timeout
1800
* @expires: timeout value (ktime_t)
1801
* @delta: slack in expires timeout (ktime_t)
1802
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1804
* Make the current task sleep until the given expiry time has
1805
* elapsed. The routine will return immediately unless
1806
* the current task state has been set (see set_current_state()).
1808
* The @delta argument gives the kernel the freedom to schedule the
1809
* actual wakeup to a time that is both power and performance friendly.
1810
* The kernel give the normal best effort behavior for "@expires+@delta",
1811
* but may decide to fire the timer earlier, but no earlier than @expires.
1813
* You can set the task state as follows -
1815
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1816
* pass before the routine returns.
1818
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1819
* delivered to the current task.
1821
* The current task state is guaranteed to be TASK_RUNNING when this
1824
* Returns 0 when the timer has expired otherwise -EINTR
1826
int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
1827
const enum hrtimer_mode mode)
1829
return schedule_hrtimeout_range_clock(expires, delta, mode,
1832
EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
1835
* schedule_hrtimeout - sleep until timeout
1836
* @expires: timeout value (ktime_t)
1837
* @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
1839
* Make the current task sleep until the given expiry time has
1840
* elapsed. The routine will return immediately unless
1841
* the current task state has been set (see set_current_state()).
1843
* You can set the task state as follows -
1845
* %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
1846
* pass before the routine returns.
1848
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1849
* delivered to the current task.
1851
* The current task state is guaranteed to be TASK_RUNNING when this
1854
* Returns 0 when the timer has expired otherwise -EINTR
1856
int __sched schedule_hrtimeout(ktime_t *expires,
1857
const enum hrtimer_mode mode)
1859
return schedule_hrtimeout_range(expires, 0, mode);
1861
EXPORT_SYMBOL_GPL(schedule_hrtimeout);