4 * Kernel internal timers, basic process system calls
6 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better.
10 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
11 * "A Kernel Model for Precision Timekeeping" by Dave Mills
12 * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
13 * serialize accesses to xtime/lost_ticks).
14 * Copyright (C) 1998 Andrea Arcangeli
15 * 1999-03-10 Improved NTP compatibility by Ulrich Windl
16 * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love
17 * 2000-10-05 Implemented scalable SMP per-CPU timer handling.
18 * Copyright (C) 2000, 2001, 2002 Ingo Molnar
19 * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
22 #include <linux/kernel_stat.h>
23 #include <linux/export.h>
24 #include <linux/interrupt.h>
25 #include <linux/percpu.h>
26 #include <linux/init.h>
28 #include <linux/swap.h>
29 #include <linux/pid_namespace.h>
30 #include <linux/notifier.h>
31 #include <linux/thread_info.h>
32 #include <linux/time.h>
33 #include <linux/jiffies.h>
34 #include <linux/posix-timers.h>
35 #include <linux/cpu.h>
36 #include <linux/syscalls.h>
37 #include <linux/delay.h>
38 #include <linux/tick.h>
39 #include <linux/kallsyms.h>
40 #include <linux/irq_work.h>
41 #include <linux/sched.h>
42 #include <linux/slab.h>
43 #include <linux/module.h>
45 #include <asm/uaccess.h>
46 #include <asm/unistd.h>
47 #include <asm/div64.h>
48 #include <asm/timex.h>
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/timer.h>
54 u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
56 EXPORT_SYMBOL(jiffies_64);
59 * per-CPU timer vector definitions:
61 #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
62 #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
63 #define TVN_SIZE (1 << TVN_BITS)
64 #define TVR_SIZE (1 << TVR_BITS)
65 #define TVN_MASK (TVN_SIZE - 1)
66 #define TVR_MASK (TVR_SIZE - 1)
69 struct list_head vec[TVN_SIZE];
73 struct list_head vec[TVR_SIZE];
78 struct timer_list *running_timer;
79 unsigned long timer_jiffies;
80 unsigned long next_timer;
86 } ____cacheline_aligned;
88 struct tvec_base boot_tvec_bases;
89 EXPORT_SYMBOL(boot_tvec_bases);
90 static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
92 /* Functions below help us manage 'deferrable' flag */
93 static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
95 return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
98 static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
100 return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));
103 static inline void timer_set_deferrable(struct timer_list *timer)
105 timer->base = TBASE_MAKE_DEFERRED(timer->base);
109 timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
111 timer->base = (struct tvec_base *)((unsigned long)(new_base) |
112 tbase_get_deferrable(timer->base));
115 static unsigned long round_jiffies_common(unsigned long j, int cpu,
119 unsigned long original = j;
122 * We don't want all cpus firing their timers at once hitting the
123 * same lock or cachelines, so we skew each extra cpu with an extra
124 * 3 jiffies. This 3 jiffies came originally from the mm/ code which
126 * The skew is done by adding 3*cpunr, then round, then subtract this
127 * extra offset again.
134 * If the target jiffie is just after a whole second (which can happen
135 * due to delays of the timer irq, long irq off times etc etc) then
136 * we should round down to the whole second, not up. Use 1/4th second
137 * as cutoff for this rounding as an extreme upper bound for this.
138 * But never round down if @force_up is set.
140 if (rem < HZ/4 && !force_up) /* round down */
145 /* now that we have rounded, subtract the extra skew again */
148 if (j <= jiffies) /* rounding ate our timeout entirely; */
154 * __round_jiffies - function to round jiffies to a full second
155 * @j: the time in (absolute) jiffies that should be rounded
156 * @cpu: the processor number on which the timeout will happen
158 * __round_jiffies() rounds an absolute time in the future (in jiffies)
159 * up or down to (approximately) full seconds. This is useful for timers
160 * for which the exact time they fire does not matter too much, as long as
161 * they fire approximately every X seconds.
163 * By rounding these timers to whole seconds, all such timers will fire
164 * at the same time, rather than at various times spread out. The goal
165 * of this is to have the CPU wake up less, which saves power.
167 * The exact rounding is skewed for each processor to avoid all
168 * processors firing at the exact same time, which could lead
169 * to lock contention or spurious cache line bouncing.
171 * The return value is the rounded version of the @j parameter.
173 unsigned long __round_jiffies(unsigned long j, int cpu)
175 return round_jiffies_common(j, cpu, false);
177 EXPORT_SYMBOL_GPL(__round_jiffies);
180 * __round_jiffies_relative - function to round jiffies to a full second
181 * @j: the time in (relative) jiffies that should be rounded
182 * @cpu: the processor number on which the timeout will happen
184 * __round_jiffies_relative() rounds a time delta in the future (in jiffies)
185 * up or down to (approximately) full seconds. This is useful for timers
186 * for which the exact time they fire does not matter too much, as long as
187 * they fire approximately every X seconds.
189 * By rounding these timers to whole seconds, all such timers will fire
190 * at the same time, rather than at various times spread out. The goal
191 * of this is to have the CPU wake up less, which saves power.
193 * The exact rounding is skewed for each processor to avoid all
194 * processors firing at the exact same time, which could lead
195 * to lock contention or spurious cache line bouncing.
197 * The return value is the rounded version of the @j parameter.
199 unsigned long __round_jiffies_relative(unsigned long j, int cpu)
201 unsigned long j0 = jiffies;
203 /* Use j0 because jiffies might change while we run */
204 return round_jiffies_common(j + j0, cpu, false) - j0;
206 EXPORT_SYMBOL_GPL(__round_jiffies_relative);
209 * round_jiffies - function to round jiffies to a full second
210 * @j: the time in (absolute) jiffies that should be rounded
212 * round_jiffies() rounds an absolute time in the future (in jiffies)
213 * up or down to (approximately) full seconds. This is useful for timers
214 * for which the exact time they fire does not matter too much, as long as
215 * they fire approximately every X seconds.
217 * By rounding these timers to whole seconds, all such timers will fire
218 * at the same time, rather than at various times spread out. The goal
219 * of this is to have the CPU wake up less, which saves power.
221 * The return value is the rounded version of the @j parameter.
223 unsigned long round_jiffies(unsigned long j)
225 return round_jiffies_common(j, raw_smp_processor_id(), false);
227 EXPORT_SYMBOL_GPL(round_jiffies);
230 * round_jiffies_relative - function to round jiffies to a full second
231 * @j: the time in (relative) jiffies that should be rounded
233 * round_jiffies_relative() rounds a time delta in the future (in jiffies)
234 * up or down to (approximately) full seconds. This is useful for timers
235 * for which the exact time they fire does not matter too much, as long as
236 * they fire approximately every X seconds.
238 * By rounding these timers to whole seconds, all such timers will fire
239 * at the same time, rather than at various times spread out. The goal
240 * of this is to have the CPU wake up less, which saves power.
242 * The return value is the rounded version of the @j parameter.
244 unsigned long round_jiffies_relative(unsigned long j)
246 return __round_jiffies_relative(j, raw_smp_processor_id());
248 EXPORT_SYMBOL_GPL(round_jiffies_relative);
251 * __round_jiffies_up - function to round jiffies up to a full second
252 * @j: the time in (absolute) jiffies that should be rounded
253 * @cpu: the processor number on which the timeout will happen
255 * This is the same as __round_jiffies() except that it will never
256 * round down. This is useful for timeouts for which the exact time
257 * of firing does not matter too much, as long as they don't fire too
260 unsigned long __round_jiffies_up(unsigned long j, int cpu)
262 return round_jiffies_common(j, cpu, true);
264 EXPORT_SYMBOL_GPL(__round_jiffies_up);
267 * __round_jiffies_up_relative - function to round jiffies up to a full second
268 * @j: the time in (relative) jiffies that should be rounded
269 * @cpu: the processor number on which the timeout will happen
271 * This is the same as __round_jiffies_relative() except that it will never
272 * round down. This is useful for timeouts for which the exact time
273 * of firing does not matter too much, as long as they don't fire too
276 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
278 unsigned long j0 = jiffies;
280 /* Use j0 because jiffies might change while we run */
281 return round_jiffies_common(j + j0, cpu, true) - j0;
283 EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
286 * round_jiffies_up - function to round jiffies up to a full second
287 * @j: the time in (absolute) jiffies that should be rounded
289 * This is the same as round_jiffies() except that it will never
290 * round down. This is useful for timeouts for which the exact time
291 * of firing does not matter too much, as long as they don't fire too
294 unsigned long round_jiffies_up(unsigned long j)
296 return round_jiffies_common(j, raw_smp_processor_id(), true);
298 EXPORT_SYMBOL_GPL(round_jiffies_up);
301 * round_jiffies_up_relative - function to round jiffies up to a full second
302 * @j: the time in (relative) jiffies that should be rounded
304 * This is the same as round_jiffies_relative() except that it will never
305 * round down. This is useful for timeouts for which the exact time
306 * of firing does not matter too much, as long as they don't fire too
309 unsigned long round_jiffies_up_relative(unsigned long j)
311 return __round_jiffies_up_relative(j, raw_smp_processor_id());
313 EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
316 * set_timer_slack - set the allowed slack for a timer
317 * @timer: the timer to be modified
318 * @slack_hz: the amount of time (in jiffies) allowed for rounding
320 * Set the amount of time, in jiffies, that a certain timer has
321 * in terms of slack. By setting this value, the timer subsystem
322 * will schedule the actual timer somewhere between
323 * the time mod_timer() asks for, and that time plus the slack.
325 * By setting the slack to -1, a percentage of the delay is used
328 void set_timer_slack(struct timer_list *timer, int slack_hz)
330 timer->slack = slack_hz;
332 EXPORT_SYMBOL_GPL(set_timer_slack);
334 static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
336 unsigned long expires = timer->expires;
337 unsigned long idx = expires - base->timer_jiffies;
338 struct list_head *vec;
340 if (idx < TVR_SIZE) {
341 int i = expires & TVR_MASK;
342 vec = base->tv1.vec + i;
343 } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
344 int i = (expires >> TVR_BITS) & TVN_MASK;
345 vec = base->tv2.vec + i;
346 } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
347 int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
348 vec = base->tv3.vec + i;
349 } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
350 int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
351 vec = base->tv4.vec + i;
352 } else if ((signed long) idx < 0) {
354 * Can happen if you add a timer with expires == jiffies,
355 * or you set a timer to go off in the past
357 vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
360 /* If the timeout is larger than 0xffffffff on 64-bit
361 * architectures then we use the maximum timeout:
363 if (idx > 0xffffffffUL) {
365 expires = idx + base->timer_jiffies;
367 i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
368 vec = base->tv5.vec + i;
373 list_add_tail(&timer->entry, vec);
376 #ifdef CONFIG_TIMER_STATS
377 void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
379 if (timer->start_site)
382 timer->start_site = addr;
383 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
384 timer->start_pid = current->pid;
387 static void timer_stats_account_timer(struct timer_list *timer)
389 unsigned int flag = 0;
391 if (likely(!timer->start_site))
393 if (unlikely(tbase_get_deferrable(timer->base)))
394 flag |= TIMER_STATS_FLAG_DEFERRABLE;
396 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
397 timer->function, timer->start_comm, flag);
401 static void timer_stats_account_timer(struct timer_list *timer) {}
404 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
406 static struct debug_obj_descr timer_debug_descr;
408 static void *timer_debug_hint(void *addr)
410 return ((struct timer_list *) addr)->function;
414 * fixup_init is called when:
415 * - an active object is initialized
417 static int timer_fixup_init(void *addr, enum debug_obj_state state)
419 struct timer_list *timer = addr;
422 case ODEBUG_STATE_ACTIVE:
423 del_timer_sync(timer);
424 debug_object_init(timer, &timer_debug_descr);
431 /* Stub timer callback for improperly used timers. */
432 static void stub_timer(unsigned long data)
438 * fixup_activate is called when:
439 * - an active object is activated
440 * - an unknown object is activated (might be a statically initialized object)
442 static int timer_fixup_activate(void *addr, enum debug_obj_state state)
444 struct timer_list *timer = addr;
448 case ODEBUG_STATE_NOTAVAILABLE:
450 * This is not really a fixup. The timer was
451 * statically initialized. We just make sure that it
452 * is tracked in the object tracker.
454 if (timer->entry.next == NULL &&
455 timer->entry.prev == TIMER_ENTRY_STATIC) {
456 debug_object_init(timer, &timer_debug_descr);
457 debug_object_activate(timer, &timer_debug_descr);
460 setup_timer(timer, stub_timer, 0);
465 case ODEBUG_STATE_ACTIVE:
474 * fixup_free is called when:
475 * - an active object is freed
477 static int timer_fixup_free(void *addr, enum debug_obj_state state)
479 struct timer_list *timer = addr;
482 case ODEBUG_STATE_ACTIVE:
483 del_timer_sync(timer);
484 debug_object_free(timer, &timer_debug_descr);
492 * fixup_assert_init is called when:
493 * - an untracked/uninit-ed object is found
495 static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
497 struct timer_list *timer = addr;
500 case ODEBUG_STATE_NOTAVAILABLE:
501 if (timer->entry.prev == TIMER_ENTRY_STATIC) {
503 * This is not really a fixup. The timer was
504 * statically initialized. We just make sure that it
505 * is tracked in the object tracker.
507 debug_object_init(timer, &timer_debug_descr);
510 setup_timer(timer, stub_timer, 0);
518 static struct debug_obj_descr timer_debug_descr = {
519 .name = "timer_list",
520 .debug_hint = timer_debug_hint,
521 .fixup_init = timer_fixup_init,
522 .fixup_activate = timer_fixup_activate,
523 .fixup_free = timer_fixup_free,
524 .fixup_assert_init = timer_fixup_assert_init,
527 static inline void debug_timer_init(struct timer_list *timer)
529 debug_object_init(timer, &timer_debug_descr);
532 static inline void debug_timer_activate(struct timer_list *timer)
534 debug_object_activate(timer, &timer_debug_descr);
537 static inline void debug_timer_deactivate(struct timer_list *timer)
539 debug_object_deactivate(timer, &timer_debug_descr);
542 static inline void debug_timer_free(struct timer_list *timer)
544 debug_object_free(timer, &timer_debug_descr);
547 static inline void debug_timer_assert_init(struct timer_list *timer)
549 debug_object_assert_init(timer, &timer_debug_descr);
552 static void __init_timer(struct timer_list *timer,
554 struct lock_class_key *key);
556 void init_timer_on_stack_key(struct timer_list *timer,
558 struct lock_class_key *key)
560 debug_object_init_on_stack(timer, &timer_debug_descr);
561 __init_timer(timer, name, key);
563 EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
565 void destroy_timer_on_stack(struct timer_list *timer)
567 debug_object_free(timer, &timer_debug_descr);
569 EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
572 static inline void debug_timer_init(struct timer_list *timer) { }
573 static inline void debug_timer_activate(struct timer_list *timer) { }
574 static inline void debug_timer_deactivate(struct timer_list *timer) { }
575 static inline void debug_timer_assert_init(struct timer_list *timer) { }
578 static inline void debug_init(struct timer_list *timer)
580 debug_timer_init(timer);
581 trace_timer_init(timer);
585 debug_activate(struct timer_list *timer, unsigned long expires)
587 debug_timer_activate(timer);
588 trace_timer_start(timer, expires);
591 static inline void debug_deactivate(struct timer_list *timer)
593 debug_timer_deactivate(timer);
594 trace_timer_cancel(timer);
597 static inline void debug_assert_init(struct timer_list *timer)
599 debug_timer_assert_init(timer);
602 static void __init_timer(struct timer_list *timer,
604 struct lock_class_key *key)
606 timer->entry.next = NULL;
607 timer->base = __raw_get_cpu_var(tvec_bases);
609 #ifdef CONFIG_TIMER_STATS
610 timer->start_site = NULL;
611 timer->start_pid = -1;
612 memset(timer->start_comm, 0, TASK_COMM_LEN);
614 lockdep_init_map(&timer->lockdep_map, name, key, 0);
617 void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
619 struct lock_class_key *key,
620 void (*function)(unsigned long),
623 timer->function = function;
625 init_timer_on_stack_key(timer, name, key);
626 timer_set_deferrable(timer);
628 EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);
631 * init_timer_key - initialize a timer
632 * @timer: the timer to be initialized
633 * @name: name of the timer
634 * @key: lockdep class key of the fake lock used for tracking timer
635 * sync lock dependencies
637 * init_timer_key() must be done to a timer prior calling *any* of the
638 * other timer functions.
640 void init_timer_key(struct timer_list *timer,
642 struct lock_class_key *key)
645 __init_timer(timer, name, key);
647 EXPORT_SYMBOL(init_timer_key);
649 void init_timer_deferrable_key(struct timer_list *timer,
651 struct lock_class_key *key)
653 init_timer_key(timer, name, key);
654 timer_set_deferrable(timer);
656 EXPORT_SYMBOL(init_timer_deferrable_key);
658 static inline void detach_timer(struct timer_list *timer,
661 struct list_head *entry = &timer->entry;
663 debug_deactivate(timer);
665 __list_del(entry->prev, entry->next);
668 entry->prev = LIST_POISON2;
672 * We are using hashed locking: holding per_cpu(tvec_bases).lock
673 * means that all timers which are tied to this base via timer->base are
674 * locked, and the base itself is locked too.
676 * So __run_timers/migrate_timers can safely modify all timers which could
677 * be found on ->tvX lists.
679 * When the timer's base is locked, and the timer removed from list, it is
680 * possible to set timer->base = NULL and drop the lock: the timer remains
683 static struct tvec_base *lock_timer_base(struct timer_list *timer,
684 unsigned long *flags)
685 __acquires(timer->base->lock)
687 struct tvec_base *base;
690 struct tvec_base *prelock_base = timer->base;
691 base = tbase_get_base(prelock_base);
692 if (likely(base != NULL)) {
693 spin_lock_irqsave(&base->lock, *flags);
694 if (likely(prelock_base == timer->base))
696 /* The timer has migrated to another CPU */
697 spin_unlock_irqrestore(&base->lock, *flags);
704 __mod_timer(struct timer_list *timer, unsigned long expires,
705 bool pending_only, int pinned)
707 struct tvec_base *base, *new_base;
711 timer_stats_timer_set_start_info(timer);
712 BUG_ON(!timer->function);
714 base = lock_timer_base(timer, &flags);
716 if (timer_pending(timer)) {
717 detach_timer(timer, 0);
718 if (timer->expires == base->next_timer &&
719 !tbase_get_deferrable(timer->base))
720 base->next_timer = base->timer_jiffies;
727 debug_activate(timer, expires);
729 cpu = smp_processor_id();
731 #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
732 if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
733 cpu = get_nohz_timer_target();
735 new_base = per_cpu(tvec_bases, cpu);
737 if (base != new_base) {
739 * We are trying to schedule the timer on the local CPU.
740 * However we can't change timer's base while it is running,
741 * otherwise del_timer_sync() can't detect that the timer's
742 * handler yet has not finished. This also guarantees that
743 * the timer is serialized wrt itself.
745 if (likely(base->running_timer != timer)) {
746 /* See the comment in lock_timer_base() */
747 timer_set_base(timer, NULL);
748 spin_unlock(&base->lock);
750 spin_lock(&base->lock);
751 timer_set_base(timer, base);
755 timer->expires = expires;
756 if (time_before(timer->expires, base->next_timer) &&
757 !tbase_get_deferrable(timer->base))
758 base->next_timer = timer->expires;
759 internal_add_timer(base, timer);
762 spin_unlock_irqrestore(&base->lock, flags);
768 * mod_timer_pending - modify a pending timer's timeout
769 * @timer: the pending timer to be modified
770 * @expires: new timeout in jiffies
772 * mod_timer_pending() is the same for pending timers as mod_timer(),
773 * but will not re-activate and modify already deleted timers.
775 * It is useful for unserialized use of timers.
777 int mod_timer_pending(struct timer_list *timer, unsigned long expires)
779 return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
781 EXPORT_SYMBOL(mod_timer_pending);
784 * Decide where to put the timer while taking the slack into account
787 * 1) calculate the maximum (absolute) time
788 * 2) calculate the highest bit where the expires and new max are different
789 * 3) use this bit to make a mask
790 * 4) use the bitmask to round down the maximum time, so that all last
794 unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
796 unsigned long expires_limit, mask;
799 if (timer->slack >= 0) {
800 expires_limit = expires + timer->slack;
802 long delta = expires - jiffies;
807 expires_limit = expires + delta / 256;
809 mask = expires ^ expires_limit;
813 bit = find_last_bit(&mask, BITS_PER_LONG);
815 mask = (1 << bit) - 1;
817 expires_limit = expires_limit & ~(mask);
819 return expires_limit;
823 * mod_timer - modify a timer's timeout
824 * @timer: the timer to be modified
825 * @expires: new timeout in jiffies
827 * mod_timer() is a more efficient way to update the expire field of an
828 * active timer (if the timer is inactive it will be activated)
830 * mod_timer(timer, expires) is equivalent to:
832 * del_timer(timer); timer->expires = expires; add_timer(timer);
834 * Note that if there are multiple unserialized concurrent users of the
835 * same timer, then mod_timer() is the only safe way to modify the timeout,
836 * since add_timer() cannot modify an already running timer.
838 * The function returns whether it has modified a pending timer or not.
839 * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
840 * active timer returns 1.)
842 int mod_timer(struct timer_list *timer, unsigned long expires)
844 expires = apply_slack(timer, expires);
847 * This is a common optimization triggered by the
848 * networking code - if the timer is re-modified
849 * to be the same thing then just return:
851 if (timer_pending(timer) && timer->expires == expires)
854 return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
856 EXPORT_SYMBOL(mod_timer);
859 * mod_timer_pinned - modify a timer's timeout
860 * @timer: the timer to be modified
861 * @expires: new timeout in jiffies
863 * mod_timer_pinned() is a way to update the expire field of an
864 * active timer (if the timer is inactive it will be activated)
865 * and not allow the timer to be migrated to a different CPU.
867 * mod_timer_pinned(timer, expires) is equivalent to:
869 * del_timer(timer); timer->expires = expires; add_timer(timer);
871 int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
873 if (timer->expires == expires && timer_pending(timer))
876 return __mod_timer(timer, expires, false, TIMER_PINNED);
878 EXPORT_SYMBOL(mod_timer_pinned);
881 * add_timer - start a timer
882 * @timer: the timer to be added
884 * The kernel will do a ->function(->data) callback from the
885 * timer interrupt at the ->expires point in the future. The
886 * current time is 'jiffies'.
888 * The timer's ->expires, ->function (and if the handler uses it, ->data)
889 * fields must be set prior calling this function.
891 * Timers with an ->expires field in the past will be executed in the next
894 void add_timer(struct timer_list *timer)
896 BUG_ON(timer_pending(timer));
897 mod_timer(timer, timer->expires);
899 EXPORT_SYMBOL(add_timer);
902 * add_timer_on - start a timer on a particular CPU
903 * @timer: the timer to be added
904 * @cpu: the CPU to start it on
906 * This is not very scalable on SMP. Double adds are not possible.
908 void add_timer_on(struct timer_list *timer, int cpu)
910 struct tvec_base *base = per_cpu(tvec_bases, cpu);
913 timer_stats_timer_set_start_info(timer);
914 BUG_ON(timer_pending(timer) || !timer->function);
915 spin_lock_irqsave(&base->lock, flags);
916 timer_set_base(timer, base);
917 debug_activate(timer, timer->expires);
918 if (time_before(timer->expires, base->next_timer) &&
919 !tbase_get_deferrable(timer->base))
920 base->next_timer = timer->expires;
921 internal_add_timer(base, timer);
923 * Check whether the other CPU is idle and needs to be
924 * triggered to reevaluate the timer wheel when nohz is
925 * active. We are protected against the other CPU fiddling
926 * with the timer by holding the timer base lock. This also
927 * makes sure that a CPU on the way to idle can not evaluate
930 wake_up_idle_cpu(cpu);
931 spin_unlock_irqrestore(&base->lock, flags);
933 EXPORT_SYMBOL_GPL(add_timer_on);
936 * del_timer - deactive a timer.
937 * @timer: the timer to be deactivated
939 * del_timer() deactivates a timer - this works on both active and inactive
942 * The function returns whether it has deactivated a pending timer or not.
943 * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
944 * active timer returns 1.)
946 int del_timer(struct timer_list *timer)
948 struct tvec_base *base;
952 debug_assert_init(timer);
954 timer_stats_timer_clear_start_info(timer);
955 if (timer_pending(timer)) {
956 base = lock_timer_base(timer, &flags);
957 if (timer_pending(timer)) {
958 detach_timer(timer, 1);
959 if (timer->expires == base->next_timer &&
960 !tbase_get_deferrable(timer->base))
961 base->next_timer = base->timer_jiffies;
964 spin_unlock_irqrestore(&base->lock, flags);
969 EXPORT_SYMBOL(del_timer);
972 * try_to_del_timer_sync - Try to deactivate a timer
973 * @timer: timer do del
975 * This function tries to deactivate a timer. Upon successful (ret >= 0)
976 * exit the timer is not queued and the handler is not running on any CPU.
978 int try_to_del_timer_sync(struct timer_list *timer)
980 struct tvec_base *base;
984 debug_assert_init(timer);
986 base = lock_timer_base(timer, &flags);
988 if (base->running_timer == timer)
991 timer_stats_timer_clear_start_info(timer);
993 if (timer_pending(timer)) {
994 detach_timer(timer, 1);
995 if (timer->expires == base->next_timer &&
996 !tbase_get_deferrable(timer->base))
997 base->next_timer = base->timer_jiffies;
1001 spin_unlock_irqrestore(&base->lock, flags);
1005 EXPORT_SYMBOL(try_to_del_timer_sync);
1009 * del_timer_sync - deactivate a timer and wait for the handler to finish.
1010 * @timer: the timer to be deactivated
1012 * This function only differs from del_timer() on SMP: besides deactivating
1013 * the timer it also makes sure the handler has finished executing on other
1016 * Synchronization rules: Callers must prevent restarting of the timer,
1017 * otherwise this function is meaningless. It must not be called from
1018 * interrupt contexts. The caller must not hold locks which would prevent
1019 * completion of the timer's handler. The timer's handler must not call
1020 * add_timer_on(). Upon exit the timer is not queued and the handler is
1021 * not running on any CPU.
1023 * Note: You must not hold locks that are held in interrupt context
1024 * while calling this function. Even if the lock has nothing to do
1025 * with the timer in question. Here's why:
1031 * base->running_timer = mytimer;
1032 * spin_lock_irq(somelock);
1034 * spin_lock(somelock);
1035 * del_timer_sync(mytimer);
1036 * while (base->running_timer == mytimer);
1038 * Now del_timer_sync() will never return and never release somelock.
1039 * The interrupt on the other CPU is waiting to grab somelock but
1040 * it has interrupted the softirq that CPU0 is waiting to finish.
1042 * The function returns whether it has deactivated a pending timer or not.
1044 int del_timer_sync(struct timer_list *timer)
1046 #ifdef CONFIG_LOCKDEP
1047 unsigned long flags;
1050 * If lockdep gives a backtrace here, please reference
1051 * the synchronization rules above.
1053 local_irq_save(flags);
1054 lock_map_acquire(&timer->lockdep_map);
1055 lock_map_release(&timer->lockdep_map);
1056 local_irq_restore(flags);
1059 * don't use it in hardirq context, because it
1060 * could lead to deadlock.
1064 int ret = try_to_del_timer_sync(timer);
1070 EXPORT_SYMBOL(del_timer_sync);
1073 static int cascade(struct tvec_base *base, struct tvec *tv, int index)
1075 /* cascade all the timers from tv up one level */
1076 struct timer_list *timer, *tmp;
1077 struct list_head tv_list;
1079 list_replace_init(tv->vec + index, &tv_list);
1082 * We are removing _all_ timers from the list, so we
1083 * don't have to detach them individually.
1085 list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
1086 BUG_ON(tbase_get_base(timer->base) != base);
1087 internal_add_timer(base, timer);
1093 static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
1096 int preempt_count = preempt_count();
1098 #ifdef CONFIG_LOCKDEP
1100 * It is permissible to free the timer from inside the
1101 * function that is called from it, this we need to take into
1102 * account for lockdep too. To avoid bogus "held lock freed"
1103 * warnings as well as problems when looking into
1104 * timer->lockdep_map, make a copy and use that here.
1106 struct lockdep_map lockdep_map = timer->lockdep_map;
1109 * Couple the lock chain with the lock chain at
1110 * del_timer_sync() by acquiring the lock_map around the fn()
1111 * call here and in del_timer_sync().
1113 lock_map_acquire(&lockdep_map);
1115 trace_timer_expire_entry(timer);
1117 trace_timer_expire_exit(timer);
1119 lock_map_release(&lockdep_map);
1121 if (preempt_count != preempt_count()) {
1122 WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
1123 fn, preempt_count, preempt_count());
1125 * Restore the preempt count. That gives us a decent
1126 * chance to survive and extract information. If the
1127 * callback kept a lock held, bad luck, but not worse
1128 * than the BUG() we had.
1130 preempt_count() = preempt_count;
1134 #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
1137 * __run_timers - run all expired timers (if any) on this CPU.
1138 * @base: the timer vector to be processed.
1140 * This function cascades all vectors and executes all expired timer
1143 static inline void __run_timers(struct tvec_base *base)
1145 struct timer_list *timer;
1147 spin_lock_irq(&base->lock);
1148 while (time_after_eq(jiffies, base->timer_jiffies)) {
1149 struct list_head work_list;
1150 struct list_head *head = &work_list;
1151 int index = base->timer_jiffies & TVR_MASK;
1157 (!cascade(base, &base->tv2, INDEX(0))) &&
1158 (!cascade(base, &base->tv3, INDEX(1))) &&
1159 !cascade(base, &base->tv4, INDEX(2)))
1160 cascade(base, &base->tv5, INDEX(3));
1161 ++base->timer_jiffies;
1162 list_replace_init(base->tv1.vec + index, &work_list);
1163 while (!list_empty(head)) {
1164 void (*fn)(unsigned long);
1167 timer = list_first_entry(head, struct timer_list,entry);
1168 fn = timer->function;
1171 timer_stats_account_timer(timer);
1173 base->running_timer = timer;
1174 detach_timer(timer, 1);
1176 spin_unlock_irq(&base->lock);
1177 call_timer_fn(timer, fn, data);
1178 spin_lock_irq(&base->lock);
1181 base->running_timer = NULL;
1182 spin_unlock_irq(&base->lock);
1187 * Find out when the next timer event is due to happen. This
1188 * is used on S/390 to stop all activity when a CPU is idle.
1189 * This function needs to be called with interrupts disabled.
1191 static unsigned long __next_timer_interrupt(struct tvec_base *base)
1193 unsigned long timer_jiffies = base->timer_jiffies;
1194 unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
1195 int index, slot, array, found = 0;
1196 struct timer_list *nte;
1197 struct tvec *varray[4];
1199 /* Look for timer events in tv1. */
1200 index = slot = timer_jiffies & TVR_MASK;
1202 list_for_each_entry(nte, base->tv1.vec + slot, entry) {
1203 if (tbase_get_deferrable(nte->base))
1207 expires = nte->expires;
1208 /* Look at the cascade bucket(s)? */
1209 if (!index || slot < index)
1213 slot = (slot + 1) & TVR_MASK;
1214 } while (slot != index);
1217 /* Calculate the next cascade event */
1219 timer_jiffies += TVR_SIZE - index;
1220 timer_jiffies >>= TVR_BITS;
1222 /* Check tv2-tv5. */
1223 varray[0] = &base->tv2;
1224 varray[1] = &base->tv3;
1225 varray[2] = &base->tv4;
1226 varray[3] = &base->tv5;
1228 for (array = 0; array < 4; array++) {
1229 struct tvec *varp = varray[array];
1231 index = slot = timer_jiffies & TVN_MASK;
1233 list_for_each_entry(nte, varp->vec + slot, entry) {
1234 if (tbase_get_deferrable(nte->base))
1238 if (time_before(nte->expires, expires))
1239 expires = nte->expires;
1242 * Do we still search for the first timer or are
1243 * we looking up the cascade buckets ?
1246 /* Look at the cascade bucket(s)? */
1247 if (!index || slot < index)
1251 slot = (slot + 1) & TVN_MASK;
1252 } while (slot != index);
1255 timer_jiffies += TVN_SIZE - index;
1256 timer_jiffies >>= TVN_BITS;
1262 * Check, if the next hrtimer event is before the next timer wheel
1265 static unsigned long cmp_next_hrtimer_event(unsigned long now,
1266 unsigned long expires)
1268 ktime_t hr_delta = hrtimer_get_next_event();
1269 struct timespec tsdelta;
1270 unsigned long delta;
1272 if (hr_delta.tv64 == KTIME_MAX)
1276 * Expired timer available, let it expire in the next tick
1278 if (hr_delta.tv64 <= 0)
1281 tsdelta = ktime_to_timespec(hr_delta);
1282 delta = timespec_to_jiffies(&tsdelta);
1285 * Limit the delta to the max value, which is checked in
1286 * tick_nohz_stop_sched_tick():
1288 if (delta > NEXT_TIMER_MAX_DELTA)
1289 delta = NEXT_TIMER_MAX_DELTA;
1292 * Take rounding errors in to account and make sure, that it
1293 * expires in the next tick. Otherwise we go into an endless
1294 * ping pong due to tick_nohz_stop_sched_tick() retriggering
1300 if (time_before(now, expires))
1306 * get_next_timer_interrupt - return the jiffy of the next pending timer
1307 * @now: current time (in jiffies)
1309 unsigned long get_next_timer_interrupt(unsigned long now)
1311 struct tvec_base *base = __this_cpu_read(tvec_bases);
1312 unsigned long expires;
1315 * Pretend that there is no timer pending if the cpu is offline.
1316 * Possible pending timers will be migrated later to an active cpu.
1318 if (cpu_is_offline(smp_processor_id()))
1319 return now + NEXT_TIMER_MAX_DELTA;
1320 spin_lock(&base->lock);
1321 if (time_before_eq(base->next_timer, base->timer_jiffies))
1322 base->next_timer = __next_timer_interrupt(base);
1323 expires = base->next_timer;
1324 spin_unlock(&base->lock);
1326 if (time_before_eq(expires, now))
1329 return cmp_next_hrtimer_event(now, expires);
1334 * Called from the timer interrupt handler to charge one tick to the current
1335 * process. user_tick is 1 if the tick is user time, 0 for system.
1337 void update_process_times(int user_tick)
1339 struct task_struct *p = current;
1340 int cpu = smp_processor_id();
1342 /* Note: this timer irq context must be accounted for as well. */
1343 account_process_tick(p, user_tick);
1345 rcu_check_callbacks(cpu, user_tick);
1347 #ifdef CONFIG_IRQ_WORK
1352 run_posix_cpu_timers(p);
1356 * This function runs timers and the timer-tq in bottom half context.
1358 static void run_timer_softirq(struct softirq_action *h)
1360 struct tvec_base *base = __this_cpu_read(tvec_bases);
1362 hrtimer_run_pending();
1364 if (time_after_eq(jiffies, base->timer_jiffies))
1369 * Called by the local, per-CPU timer interrupt on SMP.
1371 void run_local_timers(void)
1373 hrtimer_run_queues();
1374 raise_softirq(TIMER_SOFTIRQ);
1377 #ifdef __ARCH_WANT_SYS_ALARM
1380 * For backwards compatibility? This can be done in libc so Alpha
1381 * and all newer ports shouldn't need it.
1383 SYSCALL_DEFINE1(alarm, unsigned int, seconds)
1385 return alarm_setitimer(seconds);
1393 * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
1394 * should be moved into arch/i386 instead?
1398 * sys_getpid - return the thread group id of the current process
1400 * Note, despite the name, this returns the tgid not the pid. The tgid and
1401 * the pid are identical unless CLONE_THREAD was specified on clone() in
1402 * which case the tgid is the same in all threads of the same group.
1404 * This is SMP safe as current->tgid does not change.
1406 SYSCALL_DEFINE0(getpid)
1408 return task_tgid_vnr(current);
1412 * Accessing ->real_parent is not SMP-safe, it could
1413 * change from under us. However, we can use a stale
1414 * value of ->real_parent under rcu_read_lock(), see
1415 * release_task()->call_rcu(delayed_put_task_struct).
1417 SYSCALL_DEFINE0(getppid)
1422 pid = task_tgid_vnr(rcu_dereference(current->real_parent));
1428 SYSCALL_DEFINE0(getuid)
1430 /* Only we change this so SMP safe */
1431 return current_uid();
1434 SYSCALL_DEFINE0(geteuid)
1436 /* Only we change this so SMP safe */
1437 return current_euid();
1440 SYSCALL_DEFINE0(getgid)
1442 /* Only we change this so SMP safe */
1443 return current_gid();
1446 SYSCALL_DEFINE0(getegid)
1448 /* Only we change this so SMP safe */
1449 return current_egid();
1454 static void process_timeout(unsigned long __data)
1456 wake_up_process((struct task_struct *)__data);
1460 * schedule_timeout - sleep until timeout
1461 * @timeout: timeout value in jiffies
1463 * Make the current task sleep until @timeout jiffies have
1464 * elapsed. The routine will return immediately unless
1465 * the current task state has been set (see set_current_state()).
1467 * You can set the task state as follows -
1469 * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
1470 * pass before the routine returns. The routine will return 0
1472 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1473 * delivered to the current task. In this case the remaining time
1474 * in jiffies will be returned, or 0 if the timer expired in time
1476 * The current task state is guaranteed to be TASK_RUNNING when this
1479 * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
1480 * the CPU away without a bound on the timeout. In this case the return
1481 * value will be %MAX_SCHEDULE_TIMEOUT.
1483 * In all cases the return value is guaranteed to be non-negative.
1485 signed long __sched schedule_timeout(signed long timeout)
1487 struct timer_list timer;
1488 unsigned long expire;
1492 case MAX_SCHEDULE_TIMEOUT:
1494 * These two special cases are useful to be comfortable
1495 * in the caller. Nothing more. We could take
1496 * MAX_SCHEDULE_TIMEOUT from one of the negative value
1497 * but I' d like to return a valid offset (>=0) to allow
1498 * the caller to do everything it want with the retval.
1504 * Another bit of PARANOID. Note that the retval will be
1505 * 0 since no piece of kernel is supposed to do a check
1506 * for a negative retval of schedule_timeout() (since it
1507 * should never happens anyway). You just have the printk()
1508 * that will tell you if something is gone wrong and where.
1511 printk(KERN_ERR "schedule_timeout: wrong timeout "
1512 "value %lx\n", timeout);
1514 current->state = TASK_RUNNING;
1519 expire = timeout + jiffies;
1521 setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
1522 __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
1524 del_singleshot_timer_sync(&timer);
1526 /* Remove the timer from the object tracker */
1527 destroy_timer_on_stack(&timer);
1529 timeout = expire - jiffies;
1532 return timeout < 0 ? 0 : timeout;
1534 EXPORT_SYMBOL(schedule_timeout);
1537 * We can use __set_current_state() here because schedule_timeout() calls
1538 * schedule() unconditionally.
1540 signed long __sched schedule_timeout_interruptible(signed long timeout)
1542 __set_current_state(TASK_INTERRUPTIBLE);
1543 return schedule_timeout(timeout);
1545 EXPORT_SYMBOL(schedule_timeout_interruptible);
1547 signed long __sched schedule_timeout_killable(signed long timeout)
1549 __set_current_state(TASK_KILLABLE);
1550 return schedule_timeout(timeout);
1552 EXPORT_SYMBOL(schedule_timeout_killable);
1554 signed long __sched schedule_timeout_uninterruptible(signed long timeout)
1556 __set_current_state(TASK_UNINTERRUPTIBLE);
1557 return schedule_timeout(timeout);
1559 EXPORT_SYMBOL(schedule_timeout_uninterruptible);
1561 /* Thread ID - the internal kernel "pid" */
1562 SYSCALL_DEFINE0(gettid)
1564 return task_pid_vnr(current);
1568 * do_sysinfo - fill in sysinfo struct
1569 * @info: pointer to buffer to fill
1571 int do_sysinfo(struct sysinfo *info)
1573 unsigned long mem_total, sav_total;
1574 unsigned int mem_unit, bitcount;
1577 memset(info, 0, sizeof(struct sysinfo));
1580 monotonic_to_bootbased(&tp);
1581 info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
1583 get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
1585 info->procs = nr_threads;
1591 * If the sum of all the available memory (i.e. ram + swap)
1592 * is less than can be stored in a 32 bit unsigned long then
1593 * we can be binary compatible with 2.2.x kernels. If not,
1594 * well, in that case 2.2.x was broken anyways...
1596 * -Erik Andersen <andersee@debian.org>
1599 mem_total = info->totalram + info->totalswap;
1600 if (mem_total < info->totalram || mem_total < info->totalswap)
1603 mem_unit = info->mem_unit;
1604 while (mem_unit > 1) {
1607 sav_total = mem_total;
1609 if (mem_total < sav_total)
1614 * If mem_total did not overflow, multiply all memory values by
1615 * info->mem_unit and set it to 1. This leaves things compatible
1616 * with 2.2.x, and also retains compatibility with earlier 2.4.x
1621 info->totalram <<= bitcount;
1622 info->freeram <<= bitcount;
1623 info->sharedram <<= bitcount;
1624 info->bufferram <<= bitcount;
1625 info->totalswap <<= bitcount;
1626 info->freeswap <<= bitcount;
1627 info->totalhigh <<= bitcount;
1628 info->freehigh <<= bitcount;
1634 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
1640 if (copy_to_user(info, &val, sizeof(struct sysinfo)))
1646 static int __cpuinit init_timers_cpu(int cpu)
1649 struct tvec_base *base;
1650 static char __cpuinitdata tvec_base_done[NR_CPUS];
1652 if (!tvec_base_done[cpu]) {
1653 static char boot_done;
1657 * The APs use this path later in boot
1659 base = kmalloc_node(sizeof(*base),
1660 GFP_KERNEL | __GFP_ZERO,
1665 /* Make sure that tvec_base is 2 byte aligned */
1666 if (tbase_get_deferrable(base)) {
1671 per_cpu(tvec_bases, cpu) = base;
1674 * This is for the boot CPU - we use compile-time
1675 * static initialisation because per-cpu memory isn't
1676 * ready yet and because the memory allocators are not
1677 * initialised either.
1680 base = &boot_tvec_bases;
1682 tvec_base_done[cpu] = 1;
1684 base = per_cpu(tvec_bases, cpu);
1687 spin_lock_init(&base->lock);
1689 for (j = 0; j < TVN_SIZE; j++) {
1690 INIT_LIST_HEAD(base->tv5.vec + j);
1691 INIT_LIST_HEAD(base->tv4.vec + j);
1692 INIT_LIST_HEAD(base->tv3.vec + j);
1693 INIT_LIST_HEAD(base->tv2.vec + j);
1695 for (j = 0; j < TVR_SIZE; j++)
1696 INIT_LIST_HEAD(base->tv1.vec + j);
1698 base->timer_jiffies = jiffies;
1699 base->next_timer = base->timer_jiffies;
1703 #ifdef CONFIG_HOTPLUG_CPU
1704 static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
1706 struct timer_list *timer;
1708 while (!list_empty(head)) {
1709 timer = list_first_entry(head, struct timer_list, entry);
1710 detach_timer(timer, 0);
1711 timer_set_base(timer, new_base);
1712 if (time_before(timer->expires, new_base->next_timer) &&
1713 !tbase_get_deferrable(timer->base))
1714 new_base->next_timer = timer->expires;
1715 internal_add_timer(new_base, timer);
1719 static void __cpuinit migrate_timers(int cpu)
1721 struct tvec_base *old_base;
1722 struct tvec_base *new_base;
1725 BUG_ON(cpu_online(cpu));
1726 old_base = per_cpu(tvec_bases, cpu);
1727 new_base = get_cpu_var(tvec_bases);
1729 * The caller is globally serialized and nobody else
1730 * takes two locks at once, deadlock is not possible.
1732 spin_lock_irq(&new_base->lock);
1733 spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1735 BUG_ON(old_base->running_timer);
1737 for (i = 0; i < TVR_SIZE; i++)
1738 migrate_timer_list(new_base, old_base->tv1.vec + i);
1739 for (i = 0; i < TVN_SIZE; i++) {
1740 migrate_timer_list(new_base, old_base->tv2.vec + i);
1741 migrate_timer_list(new_base, old_base->tv3.vec + i);
1742 migrate_timer_list(new_base, old_base->tv4.vec + i);
1743 migrate_timer_list(new_base, old_base->tv5.vec + i);
1746 spin_unlock(&old_base->lock);
1747 spin_unlock_irq(&new_base->lock);
1748 put_cpu_var(tvec_bases);
1750 #endif /* CONFIG_HOTPLUG_CPU */
1752 static int __cpuinit timer_cpu_notify(struct notifier_block *self,
1753 unsigned long action, void *hcpu)
1755 long cpu = (long)hcpu;
1759 case CPU_UP_PREPARE:
1760 case CPU_UP_PREPARE_FROZEN:
1761 err = init_timers_cpu(cpu);
1763 return notifier_from_errno(err);
1765 #ifdef CONFIG_HOTPLUG_CPU
1767 case CPU_DEAD_FROZEN:
1768 migrate_timers(cpu);
1777 static struct notifier_block __cpuinitdata timers_nb = {
1778 .notifier_call = timer_cpu_notify,
1782 void __init init_timers(void)
1784 int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1785 (void *)(long)smp_processor_id());
1789 BUG_ON(err != NOTIFY_OK);
1790 register_cpu_notifier(&timers_nb);
1791 open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
1794 static int debug_msleep;
1795 module_param(debug_msleep, int, 0);
1798 * msleep - sleep safely even with waitqueue interruptions
1799 * @msecs: Time in milliseconds to sleep for
1801 void msleep(unsigned int msecs)
1803 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1805 if (debug_msleep && msecs >= debug_msleep)
1806 WARN(1, "Long sleep detected (%d msec)\n", msecs);
1809 timeout = schedule_timeout_uninterruptible(timeout);
1812 EXPORT_SYMBOL(msleep);
1815 * msleep_interruptible - sleep waiting for signals
1816 * @msecs: Time in milliseconds to sleep for
1818 unsigned long msleep_interruptible(unsigned int msecs)
1820 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1822 while (timeout && !signal_pending(current))
1823 timeout = schedule_timeout_interruptible(timeout);
1824 return jiffies_to_msecs(timeout);
1827 EXPORT_SYMBOL(msleep_interruptible);
1829 static int __sched do_usleep_range(unsigned long min, unsigned long max)
1832 unsigned long delta;
1834 kmin = ktime_set(0, min * NSEC_PER_USEC);
1835 delta = (max - min) * NSEC_PER_USEC;
1836 return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
1840 * usleep_range - Drop in replacement for udelay where wakeup is flexible
1841 * @min: Minimum time in usecs to sleep
1842 * @max: Maximum time in usecs to sleep
1844 void usleep_range(unsigned long min, unsigned long max)
1846 __set_current_state(TASK_UNINTERRUPTIBLE);
1847 do_usleep_range(min, max);
1849 EXPORT_SYMBOL(usleep_range);