4 * Kernel internal timers
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/sched/sysctl.h>
43 #include <linux/slab.h>
44 #include <linux/compat.h>
46 #include <asm/uaccess.h>
47 #include <asm/unistd.h>
48 #include <asm/div64.h>
49 #include <asm/timex.h>
52 #include "tick-internal.h"
54 #define CREATE_TRACE_POINTS
55 #include <trace/events/timer.h>
57 __visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
59 EXPORT_SYMBOL(jiffies_64);
62 * per-CPU timer vector definitions:
64 #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
65 #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
66 #define TVN_SIZE (1 << TVN_BITS)
67 #define TVR_SIZE (1 << TVR_BITS)
68 #define TVN_MASK (TVN_SIZE - 1)
69 #define TVR_MASK (TVR_SIZE - 1)
70 #define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1))
73 struct list_head vec[TVN_SIZE];
77 struct list_head vec[TVR_SIZE];
82 struct timer_list *running_timer;
83 unsigned long timer_jiffies;
84 unsigned long next_timer;
85 unsigned long active_timers;
86 unsigned long all_timers;
93 } ____cacheline_aligned;
96 * __TIMER_INITIALIZER() needs to set ->base to a valid pointer (because we've
97 * made NULL special, hint: lock_timer_base()) and we cannot get a compile time
98 * pointer to per-cpu entries because we don't know where we'll map the section,
99 * even for the boot cpu.
101 * And so we use boot_tvec_bases for boot CPU and per-cpu __tvec_bases for the
104 struct tvec_base boot_tvec_bases;
105 EXPORT_SYMBOL(boot_tvec_bases);
107 static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
109 /* Functions below help us manage 'deferrable' flag */
110 static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
112 return ((unsigned int)(unsigned long)base & TIMER_DEFERRABLE);
115 static inline unsigned int tbase_get_irqsafe(struct tvec_base *base)
117 return ((unsigned int)(unsigned long)base & TIMER_IRQSAFE);
120 static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
122 return ((struct tvec_base *)((unsigned long)base & ~TIMER_FLAG_MASK));
126 timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
128 unsigned long flags = (unsigned long)timer->base & TIMER_FLAG_MASK;
130 timer->base = (struct tvec_base *)((unsigned long)(new_base) | flags);
133 static unsigned long round_jiffies_common(unsigned long j, int cpu,
137 unsigned long original = j;
140 * We don't want all cpus firing their timers at once hitting the
141 * same lock or cachelines, so we skew each extra cpu with an extra
142 * 3 jiffies. This 3 jiffies came originally from the mm/ code which
144 * The skew is done by adding 3*cpunr, then round, then subtract this
145 * extra offset again.
152 * If the target jiffie is just after a whole second (which can happen
153 * due to delays of the timer irq, long irq off times etc etc) then
154 * we should round down to the whole second, not up. Use 1/4th second
155 * as cutoff for this rounding as an extreme upper bound for this.
156 * But never round down if @force_up is set.
158 if (rem < HZ/4 && !force_up) /* round down */
163 /* now that we have rounded, subtract the extra skew again */
167 * Make sure j is still in the future. Otherwise return the
170 return time_is_after_jiffies(j) ? j : original;
174 * __round_jiffies - function to round jiffies to a full second
175 * @j: the time in (absolute) jiffies that should be rounded
176 * @cpu: the processor number on which the timeout will happen
178 * __round_jiffies() rounds an absolute time in the future (in jiffies)
179 * up or down to (approximately) full seconds. This is useful for timers
180 * for which the exact time they fire does not matter too much, as long as
181 * they fire approximately every X seconds.
183 * By rounding these timers to whole seconds, all such timers will fire
184 * at the same time, rather than at various times spread out. The goal
185 * of this is to have the CPU wake up less, which saves power.
187 * The exact rounding is skewed for each processor to avoid all
188 * processors firing at the exact same time, which could lead
189 * to lock contention or spurious cache line bouncing.
191 * The return value is the rounded version of the @j parameter.
193 unsigned long __round_jiffies(unsigned long j, int cpu)
195 return round_jiffies_common(j, cpu, false);
197 EXPORT_SYMBOL_GPL(__round_jiffies);
200 * __round_jiffies_relative - function to round jiffies to a full second
201 * @j: the time in (relative) jiffies that should be rounded
202 * @cpu: the processor number on which the timeout will happen
204 * __round_jiffies_relative() rounds a time delta in the future (in jiffies)
205 * up or down to (approximately) full seconds. This is useful for timers
206 * for which the exact time they fire does not matter too much, as long as
207 * they fire approximately every X seconds.
209 * By rounding these timers to whole seconds, all such timers will fire
210 * at the same time, rather than at various times spread out. The goal
211 * of this is to have the CPU wake up less, which saves power.
213 * The exact rounding is skewed for each processor to avoid all
214 * processors firing at the exact same time, which could lead
215 * to lock contention or spurious cache line bouncing.
217 * The return value is the rounded version of the @j parameter.
219 unsigned long __round_jiffies_relative(unsigned long j, int cpu)
221 unsigned long j0 = jiffies;
223 /* Use j0 because jiffies might change while we run */
224 return round_jiffies_common(j + j0, cpu, false) - j0;
226 EXPORT_SYMBOL_GPL(__round_jiffies_relative);
229 * round_jiffies - function to round jiffies to a full second
230 * @j: the time in (absolute) jiffies that should be rounded
232 * round_jiffies() rounds an absolute time in the future (in jiffies)
233 * up or down to (approximately) full seconds. This is useful for timers
234 * for which the exact time they fire does not matter too much, as long as
235 * they fire approximately every X seconds.
237 * By rounding these timers to whole seconds, all such timers will fire
238 * at the same time, rather than at various times spread out. The goal
239 * of this is to have the CPU wake up less, which saves power.
241 * The return value is the rounded version of the @j parameter.
243 unsigned long round_jiffies(unsigned long j)
245 return round_jiffies_common(j, raw_smp_processor_id(), false);
247 EXPORT_SYMBOL_GPL(round_jiffies);
250 * round_jiffies_relative - function to round jiffies to a full second
251 * @j: the time in (relative) jiffies that should be rounded
253 * round_jiffies_relative() rounds a time delta in the future (in jiffies)
254 * up or down to (approximately) full seconds. This is useful for timers
255 * for which the exact time they fire does not matter too much, as long as
256 * they fire approximately every X seconds.
258 * By rounding these timers to whole seconds, all such timers will fire
259 * at the same time, rather than at various times spread out. The goal
260 * of this is to have the CPU wake up less, which saves power.
262 * The return value is the rounded version of the @j parameter.
264 unsigned long round_jiffies_relative(unsigned long j)
266 return __round_jiffies_relative(j, raw_smp_processor_id());
268 EXPORT_SYMBOL_GPL(round_jiffies_relative);
271 * __round_jiffies_up - function to round jiffies up to a full second
272 * @j: the time in (absolute) jiffies that should be rounded
273 * @cpu: the processor number on which the timeout will happen
275 * This is the same as __round_jiffies() except that it will never
276 * round down. This is useful for timeouts for which the exact time
277 * of firing does not matter too much, as long as they don't fire too
280 unsigned long __round_jiffies_up(unsigned long j, int cpu)
282 return round_jiffies_common(j, cpu, true);
284 EXPORT_SYMBOL_GPL(__round_jiffies_up);
287 * __round_jiffies_up_relative - function to round jiffies up to a full second
288 * @j: the time in (relative) jiffies that should be rounded
289 * @cpu: the processor number on which the timeout will happen
291 * This is the same as __round_jiffies_relative() except that it will never
292 * round down. This is useful for timeouts for which the exact time
293 * of firing does not matter too much, as long as they don't fire too
296 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
298 unsigned long j0 = jiffies;
300 /* Use j0 because jiffies might change while we run */
301 return round_jiffies_common(j + j0, cpu, true) - j0;
303 EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
306 * round_jiffies_up - function to round jiffies up to a full second
307 * @j: the time in (absolute) jiffies that should be rounded
309 * This is the same as round_jiffies() except that it will never
310 * round down. This is useful for timeouts for which the exact time
311 * of firing does not matter too much, as long as they don't fire too
314 unsigned long round_jiffies_up(unsigned long j)
316 return round_jiffies_common(j, raw_smp_processor_id(), true);
318 EXPORT_SYMBOL_GPL(round_jiffies_up);
321 * round_jiffies_up_relative - function to round jiffies up to a full second
322 * @j: the time in (relative) jiffies that should be rounded
324 * This is the same as round_jiffies_relative() except that it will never
325 * round down. This is useful for timeouts for which the exact time
326 * of firing does not matter too much, as long as they don't fire too
329 unsigned long round_jiffies_up_relative(unsigned long j)
331 return __round_jiffies_up_relative(j, raw_smp_processor_id());
333 EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
336 * set_timer_slack - set the allowed slack for a timer
337 * @timer: the timer to be modified
338 * @slack_hz: the amount of time (in jiffies) allowed for rounding
340 * Set the amount of time, in jiffies, that a certain timer has
341 * in terms of slack. By setting this value, the timer subsystem
342 * will schedule the actual timer somewhere between
343 * the time mod_timer() asks for, and that time plus the slack.
345 * By setting the slack to -1, a percentage of the delay is used
348 void set_timer_slack(struct timer_list *timer, int slack_hz)
350 timer->slack = slack_hz;
352 EXPORT_SYMBOL_GPL(set_timer_slack);
355 __internal_add_timer(struct tvec_base *base, struct timer_list *timer)
357 unsigned long expires = timer->expires;
358 unsigned long idx = expires - base->timer_jiffies;
359 struct list_head *vec;
361 if (idx < TVR_SIZE) {
362 int i = expires & TVR_MASK;
363 vec = base->tv1.vec + i;
364 } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
365 int i = (expires >> TVR_BITS) & TVN_MASK;
366 vec = base->tv2.vec + i;
367 } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
368 int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
369 vec = base->tv3.vec + i;
370 } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
371 int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
372 vec = base->tv4.vec + i;
373 } else if ((signed long) idx < 0) {
375 * Can happen if you add a timer with expires == jiffies,
376 * or you set a timer to go off in the past
378 vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
381 /* If the timeout is larger than MAX_TVAL (on 64-bit
382 * architectures or with CONFIG_BASE_SMALL=1) then we
383 * use the maximum timeout.
385 if (idx > MAX_TVAL) {
387 expires = idx + base->timer_jiffies;
389 i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
390 vec = base->tv5.vec + i;
395 list_add_tail(&timer->entry, vec);
398 static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
400 /* Advance base->jiffies, if the base is empty */
401 if (!base->all_timers++)
402 base->timer_jiffies = jiffies;
404 __internal_add_timer(base, timer);
406 * Update base->active_timers and base->next_timer
408 if (!tbase_get_deferrable(timer->base)) {
409 if (!base->active_timers++ ||
410 time_before(timer->expires, base->next_timer))
411 base->next_timer = timer->expires;
415 * Check whether the other CPU is in dynticks mode and needs
416 * to be triggered to reevaluate the timer wheel.
417 * We are protected against the other CPU fiddling
418 * with the timer by holding the timer base lock. This also
419 * makes sure that a CPU on the way to stop its tick can not
420 * evaluate the timer wheel.
422 * Spare the IPI for deferrable timers on idle targets though.
423 * The next busy ticks will take care of it. Except full dynticks
424 * require special care against races with idle_cpu(), lets deal
427 if (!tbase_get_deferrable(timer->base) || tick_nohz_full_cpu(base->cpu))
428 wake_up_nohz_cpu(base->cpu);
431 #ifdef CONFIG_TIMER_STATS
432 void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
434 if (timer->start_site)
437 timer->start_site = addr;
438 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
439 timer->start_pid = current->pid;
442 static void timer_stats_account_timer(struct timer_list *timer)
444 unsigned int flag = 0;
446 if (likely(!timer->start_site))
448 if (unlikely(tbase_get_deferrable(timer->base)))
449 flag |= TIMER_STATS_FLAG_DEFERRABLE;
451 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
452 timer->function, timer->start_comm, flag);
456 static void timer_stats_account_timer(struct timer_list *timer) {}
459 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
461 static struct debug_obj_descr timer_debug_descr;
463 static void *timer_debug_hint(void *addr)
465 return ((struct timer_list *) addr)->function;
469 * fixup_init is called when:
470 * - an active object is initialized
472 static int timer_fixup_init(void *addr, enum debug_obj_state state)
474 struct timer_list *timer = addr;
477 case ODEBUG_STATE_ACTIVE:
478 del_timer_sync(timer);
479 debug_object_init(timer, &timer_debug_descr);
486 /* Stub timer callback for improperly used timers. */
487 static void stub_timer(unsigned long data)
493 * fixup_activate is called when:
494 * - an active object is activated
495 * - an unknown object is activated (might be a statically initialized object)
497 static int timer_fixup_activate(void *addr, enum debug_obj_state state)
499 struct timer_list *timer = addr;
503 case ODEBUG_STATE_NOTAVAILABLE:
505 * This is not really a fixup. The timer was
506 * statically initialized. We just make sure that it
507 * is tracked in the object tracker.
509 if (timer->entry.next == NULL &&
510 timer->entry.prev == TIMER_ENTRY_STATIC) {
511 debug_object_init(timer, &timer_debug_descr);
512 debug_object_activate(timer, &timer_debug_descr);
515 setup_timer(timer, stub_timer, 0);
520 case ODEBUG_STATE_ACTIVE:
529 * fixup_free is called when:
530 * - an active object is freed
532 static int timer_fixup_free(void *addr, enum debug_obj_state state)
534 struct timer_list *timer = addr;
537 case ODEBUG_STATE_ACTIVE:
538 del_timer_sync(timer);
539 debug_object_free(timer, &timer_debug_descr);
547 * fixup_assert_init is called when:
548 * - an untracked/uninit-ed object is found
550 static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
552 struct timer_list *timer = addr;
555 case ODEBUG_STATE_NOTAVAILABLE:
556 if (timer->entry.prev == TIMER_ENTRY_STATIC) {
558 * This is not really a fixup. The timer was
559 * statically initialized. We just make sure that it
560 * is tracked in the object tracker.
562 debug_object_init(timer, &timer_debug_descr);
565 setup_timer(timer, stub_timer, 0);
573 static struct debug_obj_descr timer_debug_descr = {
574 .name = "timer_list",
575 .debug_hint = timer_debug_hint,
576 .fixup_init = timer_fixup_init,
577 .fixup_activate = timer_fixup_activate,
578 .fixup_free = timer_fixup_free,
579 .fixup_assert_init = timer_fixup_assert_init,
582 static inline void debug_timer_init(struct timer_list *timer)
584 debug_object_init(timer, &timer_debug_descr);
587 static inline void debug_timer_activate(struct timer_list *timer)
589 debug_object_activate(timer, &timer_debug_descr);
592 static inline void debug_timer_deactivate(struct timer_list *timer)
594 debug_object_deactivate(timer, &timer_debug_descr);
597 static inline void debug_timer_free(struct timer_list *timer)
599 debug_object_free(timer, &timer_debug_descr);
602 static inline void debug_timer_assert_init(struct timer_list *timer)
604 debug_object_assert_init(timer, &timer_debug_descr);
607 static void do_init_timer(struct timer_list *timer, unsigned int flags,
608 const char *name, struct lock_class_key *key);
610 void init_timer_on_stack_key(struct timer_list *timer, unsigned int flags,
611 const char *name, struct lock_class_key *key)
613 debug_object_init_on_stack(timer, &timer_debug_descr);
614 do_init_timer(timer, flags, name, key);
616 EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
618 void destroy_timer_on_stack(struct timer_list *timer)
620 debug_object_free(timer, &timer_debug_descr);
622 EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
625 static inline void debug_timer_init(struct timer_list *timer) { }
626 static inline void debug_timer_activate(struct timer_list *timer) { }
627 static inline void debug_timer_deactivate(struct timer_list *timer) { }
628 static inline void debug_timer_assert_init(struct timer_list *timer) { }
631 static inline void debug_init(struct timer_list *timer)
633 debug_timer_init(timer);
634 trace_timer_init(timer);
638 debug_activate(struct timer_list *timer, unsigned long expires)
640 debug_timer_activate(timer);
641 trace_timer_start(timer, expires, tbase_get_deferrable(timer->base));
644 static inline void debug_deactivate(struct timer_list *timer)
646 debug_timer_deactivate(timer);
647 trace_timer_cancel(timer);
650 static inline void debug_assert_init(struct timer_list *timer)
652 debug_timer_assert_init(timer);
655 static void do_init_timer(struct timer_list *timer, unsigned int flags,
656 const char *name, struct lock_class_key *key)
658 struct tvec_base *base = raw_cpu_read(tvec_bases);
660 timer->entry.next = NULL;
661 timer->base = (void *)((unsigned long)base | flags);
663 #ifdef CONFIG_TIMER_STATS
664 timer->start_site = NULL;
665 timer->start_pid = -1;
666 memset(timer->start_comm, 0, TASK_COMM_LEN);
668 lockdep_init_map(&timer->lockdep_map, name, key, 0);
672 * init_timer_key - initialize a timer
673 * @timer: the timer to be initialized
674 * @flags: timer flags
675 * @name: name of the timer
676 * @key: lockdep class key of the fake lock used for tracking timer
677 * sync lock dependencies
679 * init_timer_key() must be done to a timer prior calling *any* of the
680 * other timer functions.
682 void init_timer_key(struct timer_list *timer, unsigned int flags,
683 const char *name, struct lock_class_key *key)
686 do_init_timer(timer, flags, name, key);
688 EXPORT_SYMBOL(init_timer_key);
690 static inline void detach_timer(struct timer_list *timer, bool clear_pending)
692 struct list_head *entry = &timer->entry;
694 debug_deactivate(timer);
696 __list_del(entry->prev, entry->next);
699 entry->prev = LIST_POISON2;
703 detach_expired_timer(struct timer_list *timer, struct tvec_base *base)
705 detach_timer(timer, true);
706 if (!tbase_get_deferrable(timer->base))
707 base->active_timers--;
711 static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
714 if (!timer_pending(timer))
717 detach_timer(timer, clear_pending);
718 if (!tbase_get_deferrable(timer->base)) {
719 base->active_timers--;
720 if (timer->expires == base->next_timer)
721 base->next_timer = base->timer_jiffies;
723 /* If this was the last timer, advance base->jiffies */
724 if (!--base->all_timers)
725 base->timer_jiffies = jiffies;
730 * We are using hashed locking: holding per_cpu(tvec_bases).lock
731 * means that all timers which are tied to this base via timer->base are
732 * locked, and the base itself is locked too.
734 * So __run_timers/migrate_timers can safely modify all timers which could
735 * be found on ->tvX lists.
737 * When the timer's base is locked, and the timer removed from list, it is
738 * possible to set timer->base = NULL and drop the lock: the timer remains
741 static struct tvec_base *lock_timer_base(struct timer_list *timer,
742 unsigned long *flags)
743 __acquires(timer->base->lock)
745 struct tvec_base *base;
748 struct tvec_base *prelock_base = timer->base;
749 base = tbase_get_base(prelock_base);
750 if (likely(base != NULL)) {
751 spin_lock_irqsave(&base->lock, *flags);
752 if (likely(prelock_base == timer->base))
754 /* The timer has migrated to another CPU */
755 spin_unlock_irqrestore(&base->lock, *flags);
762 __mod_timer(struct timer_list *timer, unsigned long expires,
763 bool pending_only, int pinned)
765 struct tvec_base *base, *new_base;
769 timer_stats_timer_set_start_info(timer);
770 BUG_ON(!timer->function);
772 base = lock_timer_base(timer, &flags);
774 ret = detach_if_pending(timer, base, false);
775 if (!ret && pending_only)
778 debug_activate(timer, expires);
780 cpu = get_nohz_timer_target(pinned);
781 new_base = per_cpu(tvec_bases, cpu);
783 if (base != new_base) {
785 * We are trying to schedule the timer on the local CPU.
786 * However we can't change timer's base while it is running,
787 * otherwise del_timer_sync() can't detect that the timer's
788 * handler yet has not finished. This also guarantees that
789 * the timer is serialized wrt itself.
791 if (likely(base->running_timer != timer)) {
792 /* See the comment in lock_timer_base() */
793 timer_set_base(timer, NULL);
794 spin_unlock(&base->lock);
796 spin_lock(&base->lock);
797 timer_set_base(timer, base);
801 timer->expires = expires;
802 internal_add_timer(base, timer);
805 spin_unlock_irqrestore(&base->lock, flags);
811 * mod_timer_pending - modify a pending timer's timeout
812 * @timer: the pending timer to be modified
813 * @expires: new timeout in jiffies
815 * mod_timer_pending() is the same for pending timers as mod_timer(),
816 * but will not re-activate and modify already deleted timers.
818 * It is useful for unserialized use of timers.
820 int mod_timer_pending(struct timer_list *timer, unsigned long expires)
822 return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
824 EXPORT_SYMBOL(mod_timer_pending);
827 * Decide where to put the timer while taking the slack into account
830 * 1) calculate the maximum (absolute) time
831 * 2) calculate the highest bit where the expires and new max are different
832 * 3) use this bit to make a mask
833 * 4) use the bitmask to round down the maximum time, so that all last
837 unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
839 unsigned long expires_limit, mask;
842 if (timer->slack >= 0) {
843 expires_limit = expires + timer->slack;
845 long delta = expires - jiffies;
850 expires_limit = expires + delta / 256;
852 mask = expires ^ expires_limit;
856 bit = find_last_bit(&mask, BITS_PER_LONG);
858 mask = (1UL << bit) - 1;
860 expires_limit = expires_limit & ~(mask);
862 return expires_limit;
866 * mod_timer - modify a timer's timeout
867 * @timer: the timer to be modified
868 * @expires: new timeout in jiffies
870 * mod_timer() is a more efficient way to update the expire field of an
871 * active timer (if the timer is inactive it will be activated)
873 * mod_timer(timer, expires) is equivalent to:
875 * del_timer(timer); timer->expires = expires; add_timer(timer);
877 * Note that if there are multiple unserialized concurrent users of the
878 * same timer, then mod_timer() is the only safe way to modify the timeout,
879 * since add_timer() cannot modify an already running timer.
881 * The function returns whether it has modified a pending timer or not.
882 * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
883 * active timer returns 1.)
885 int mod_timer(struct timer_list *timer, unsigned long expires)
887 expires = apply_slack(timer, expires);
890 * This is a common optimization triggered by the
891 * networking code - if the timer is re-modified
892 * to be the same thing then just return:
894 if (timer_pending(timer) && timer->expires == expires)
897 return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
899 EXPORT_SYMBOL(mod_timer);
902 * mod_timer_pinned - modify a timer's timeout
903 * @timer: the timer to be modified
904 * @expires: new timeout in jiffies
906 * mod_timer_pinned() is a way to update the expire field of an
907 * active timer (if the timer is inactive it will be activated)
908 * and to ensure that the timer is scheduled on the current CPU.
910 * Note that this does not prevent the timer from being migrated
911 * when the current CPU goes offline. If this is a problem for
912 * you, use CPU-hotplug notifiers to handle it correctly, for
913 * example, cancelling the timer when the corresponding CPU goes
916 * mod_timer_pinned(timer, expires) is equivalent to:
918 * del_timer(timer); timer->expires = expires; add_timer(timer);
920 int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
922 if (timer->expires == expires && timer_pending(timer))
925 return __mod_timer(timer, expires, false, TIMER_PINNED);
927 EXPORT_SYMBOL(mod_timer_pinned);
930 * add_timer - start a timer
931 * @timer: the timer to be added
933 * The kernel will do a ->function(->data) callback from the
934 * timer interrupt at the ->expires point in the future. The
935 * current time is 'jiffies'.
937 * The timer's ->expires, ->function (and if the handler uses it, ->data)
938 * fields must be set prior calling this function.
940 * Timers with an ->expires field in the past will be executed in the next
943 void add_timer(struct timer_list *timer)
945 BUG_ON(timer_pending(timer));
946 mod_timer(timer, timer->expires);
948 EXPORT_SYMBOL(add_timer);
951 * add_timer_on - start a timer on a particular CPU
952 * @timer: the timer to be added
953 * @cpu: the CPU to start it on
955 * This is not very scalable on SMP. Double adds are not possible.
957 void add_timer_on(struct timer_list *timer, int cpu)
959 struct tvec_base *base = per_cpu(tvec_bases, cpu);
962 timer_stats_timer_set_start_info(timer);
963 BUG_ON(timer_pending(timer) || !timer->function);
964 spin_lock_irqsave(&base->lock, flags);
965 timer_set_base(timer, base);
966 debug_activate(timer, timer->expires);
967 internal_add_timer(base, timer);
968 spin_unlock_irqrestore(&base->lock, flags);
970 EXPORT_SYMBOL_GPL(add_timer_on);
973 * del_timer - deactive a timer.
974 * @timer: the timer to be deactivated
976 * del_timer() deactivates a timer - this works on both active and inactive
979 * The function returns whether it has deactivated a pending timer or not.
980 * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
981 * active timer returns 1.)
983 int del_timer(struct timer_list *timer)
985 struct tvec_base *base;
989 debug_assert_init(timer);
991 timer_stats_timer_clear_start_info(timer);
992 if (timer_pending(timer)) {
993 base = lock_timer_base(timer, &flags);
994 ret = detach_if_pending(timer, base, true);
995 spin_unlock_irqrestore(&base->lock, flags);
1000 EXPORT_SYMBOL(del_timer);
1003 * try_to_del_timer_sync - Try to deactivate a timer
1004 * @timer: timer do del
1006 * This function tries to deactivate a timer. Upon successful (ret >= 0)
1007 * exit the timer is not queued and the handler is not running on any CPU.
1009 int try_to_del_timer_sync(struct timer_list *timer)
1011 struct tvec_base *base;
1012 unsigned long flags;
1015 debug_assert_init(timer);
1017 base = lock_timer_base(timer, &flags);
1019 if (base->running_timer != timer) {
1020 timer_stats_timer_clear_start_info(timer);
1021 ret = detach_if_pending(timer, base, true);
1023 spin_unlock_irqrestore(&base->lock, flags);
1027 EXPORT_SYMBOL(try_to_del_timer_sync);
1030 static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);
1033 * del_timer_sync - deactivate a timer and wait for the handler to finish.
1034 * @timer: the timer to be deactivated
1036 * This function only differs from del_timer() on SMP: besides deactivating
1037 * the timer it also makes sure the handler has finished executing on other
1040 * Synchronization rules: Callers must prevent restarting of the timer,
1041 * otherwise this function is meaningless. It must not be called from
1042 * interrupt contexts unless the timer is an irqsafe one. The caller must
1043 * not hold locks which would prevent completion of the timer's
1044 * handler. The timer's handler must not call add_timer_on(). Upon exit the
1045 * timer is not queued and the handler is not running on any CPU.
1047 * Note: For !irqsafe timers, you must not hold locks that are held in
1048 * interrupt context while calling this function. Even if the lock has
1049 * nothing to do with the timer in question. Here's why:
1055 * base->running_timer = mytimer;
1056 * spin_lock_irq(somelock);
1058 * spin_lock(somelock);
1059 * del_timer_sync(mytimer);
1060 * while (base->running_timer == mytimer);
1062 * Now del_timer_sync() will never return and never release somelock.
1063 * The interrupt on the other CPU is waiting to grab somelock but
1064 * it has interrupted the softirq that CPU0 is waiting to finish.
1066 * The function returns whether it has deactivated a pending timer or not.
1068 int del_timer_sync(struct timer_list *timer)
1070 #ifdef CONFIG_LOCKDEP
1071 unsigned long flags;
1074 * If lockdep gives a backtrace here, please reference
1075 * the synchronization rules above.
1077 local_irq_save(flags);
1078 lock_map_acquire(&timer->lockdep_map);
1079 lock_map_release(&timer->lockdep_map);
1080 local_irq_restore(flags);
1083 * don't use it in hardirq context, because it
1084 * could lead to deadlock.
1086 WARN_ON(in_irq() && !tbase_get_irqsafe(timer->base));
1088 int ret = try_to_del_timer_sync(timer);
1094 EXPORT_SYMBOL(del_timer_sync);
1097 static int cascade(struct tvec_base *base, struct tvec *tv, int index)
1099 /* cascade all the timers from tv up one level */
1100 struct timer_list *timer, *tmp;
1101 struct list_head tv_list;
1103 list_replace_init(tv->vec + index, &tv_list);
1106 * We are removing _all_ timers from the list, so we
1107 * don't have to detach them individually.
1109 list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
1110 BUG_ON(tbase_get_base(timer->base) != base);
1111 /* No accounting, while moving them */
1112 __internal_add_timer(base, timer);
1118 static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
1121 int count = preempt_count();
1123 #ifdef CONFIG_LOCKDEP
1125 * It is permissible to free the timer from inside the
1126 * function that is called from it, this we need to take into
1127 * account for lockdep too. To avoid bogus "held lock freed"
1128 * warnings as well as problems when looking into
1129 * timer->lockdep_map, make a copy and use that here.
1131 struct lockdep_map lockdep_map;
1133 lockdep_copy_map(&lockdep_map, &timer->lockdep_map);
1136 * Couple the lock chain with the lock chain at
1137 * del_timer_sync() by acquiring the lock_map around the fn()
1138 * call here and in del_timer_sync().
1140 lock_map_acquire(&lockdep_map);
1142 trace_timer_expire_entry(timer);
1144 trace_timer_expire_exit(timer);
1146 lock_map_release(&lockdep_map);
1148 if (count != preempt_count()) {
1149 WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
1150 fn, count, preempt_count());
1152 * Restore the preempt count. That gives us a decent
1153 * chance to survive and extract information. If the
1154 * callback kept a lock held, bad luck, but not worse
1155 * than the BUG() we had.
1157 preempt_count_set(count);
1161 #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
1164 * __run_timers - run all expired timers (if any) on this CPU.
1165 * @base: the timer vector to be processed.
1167 * This function cascades all vectors and executes all expired timer
1170 static inline void __run_timers(struct tvec_base *base)
1172 struct timer_list *timer;
1174 spin_lock_irq(&base->lock);
1176 while (time_after_eq(jiffies, base->timer_jiffies)) {
1177 struct list_head work_list;
1178 struct list_head *head = &work_list;
1181 if (!base->all_timers) {
1182 base->timer_jiffies = jiffies;
1186 index = base->timer_jiffies & TVR_MASK;
1192 (!cascade(base, &base->tv2, INDEX(0))) &&
1193 (!cascade(base, &base->tv3, INDEX(1))) &&
1194 !cascade(base, &base->tv4, INDEX(2)))
1195 cascade(base, &base->tv5, INDEX(3));
1196 ++base->timer_jiffies;
1197 list_replace_init(base->tv1.vec + index, head);
1198 while (!list_empty(head)) {
1199 void (*fn)(unsigned long);
1203 timer = list_first_entry(head, struct timer_list,entry);
1204 fn = timer->function;
1206 irqsafe = tbase_get_irqsafe(timer->base);
1208 timer_stats_account_timer(timer);
1210 base->running_timer = timer;
1211 detach_expired_timer(timer, base);
1214 spin_unlock(&base->lock);
1215 call_timer_fn(timer, fn, data);
1216 spin_lock(&base->lock);
1218 spin_unlock_irq(&base->lock);
1219 call_timer_fn(timer, fn, data);
1220 spin_lock_irq(&base->lock);
1224 base->running_timer = NULL;
1225 spin_unlock_irq(&base->lock);
1228 #ifdef CONFIG_NO_HZ_COMMON
1230 * Find out when the next timer event is due to happen. This
1231 * is used on S/390 to stop all activity when a CPU is idle.
1232 * This function needs to be called with interrupts disabled.
1234 static unsigned long __next_timer_interrupt(struct tvec_base *base)
1236 unsigned long timer_jiffies = base->timer_jiffies;
1237 unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
1238 int index, slot, array, found = 0;
1239 struct timer_list *nte;
1240 struct tvec *varray[4];
1242 /* Look for timer events in tv1. */
1243 index = slot = timer_jiffies & TVR_MASK;
1245 list_for_each_entry(nte, base->tv1.vec + slot, entry) {
1246 if (tbase_get_deferrable(nte->base))
1250 expires = nte->expires;
1251 /* Look at the cascade bucket(s)? */
1252 if (!index || slot < index)
1256 slot = (slot + 1) & TVR_MASK;
1257 } while (slot != index);
1260 /* Calculate the next cascade event */
1262 timer_jiffies += TVR_SIZE - index;
1263 timer_jiffies >>= TVR_BITS;
1265 /* Check tv2-tv5. */
1266 varray[0] = &base->tv2;
1267 varray[1] = &base->tv3;
1268 varray[2] = &base->tv4;
1269 varray[3] = &base->tv5;
1271 for (array = 0; array < 4; array++) {
1272 struct tvec *varp = varray[array];
1274 index = slot = timer_jiffies & TVN_MASK;
1276 list_for_each_entry(nte, varp->vec + slot, entry) {
1277 if (tbase_get_deferrable(nte->base))
1281 if (time_before(nte->expires, expires))
1282 expires = nte->expires;
1285 * Do we still search for the first timer or are
1286 * we looking up the cascade buckets ?
1289 /* Look at the cascade bucket(s)? */
1290 if (!index || slot < index)
1294 slot = (slot + 1) & TVN_MASK;
1295 } while (slot != index);
1298 timer_jiffies += TVN_SIZE - index;
1299 timer_jiffies >>= TVN_BITS;
1305 * Check, if the next hrtimer event is before the next timer wheel
1308 static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
1310 u64 nextevt = hrtimer_get_next_event();
1313 * If high resolution timers are enabled
1314 * hrtimer_get_next_event() returns KTIME_MAX.
1316 if (expires <= nextevt)
1320 * If the next timer is already expired, return the tick base
1321 * time so the tick is fired immediately.
1323 if (nextevt <= basem)
1327 * Round up to the next jiffie. High resolution timers are
1328 * off, so the hrtimers are expired in the tick and we need to
1329 * make sure that this tick really expires the timer to avoid
1330 * a ping pong of the nohz stop code.
1332 * Use DIV_ROUND_UP_ULL to prevent gcc calling __divdi3
1334 return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
1338 * get_next_timer_interrupt - return the time (clock mono) of the next timer
1339 * @basej: base time jiffies
1340 * @basem: base time clock monotonic
1342 * Returns the tick aligned clock monotonic time of the next pending
1343 * timer or KTIME_MAX if no timer is pending.
1345 u64 get_next_timer_interrupt(unsigned long basej, u64 basem)
1347 struct tvec_base *base = __this_cpu_read(tvec_bases);
1348 u64 expires = KTIME_MAX;
1349 unsigned long nextevt;
1352 * Pretend that there is no timer pending if the cpu is offline.
1353 * Possible pending timers will be migrated later to an active cpu.
1355 if (cpu_is_offline(smp_processor_id()))
1358 spin_lock(&base->lock);
1359 if (base->active_timers) {
1360 if (time_before_eq(base->next_timer, base->timer_jiffies))
1361 base->next_timer = __next_timer_interrupt(base);
1362 nextevt = base->next_timer;
1363 if (time_before_eq(nextevt, basej))
1366 expires = basem + (nextevt - basej) * TICK_NSEC;
1368 spin_unlock(&base->lock);
1370 return cmp_next_hrtimer_event(basem, expires);
1375 * Called from the timer interrupt handler to charge one tick to the current
1376 * process. user_tick is 1 if the tick is user time, 0 for system.
1378 void update_process_times(int user_tick)
1380 struct task_struct *p = current;
1382 /* Note: this timer irq context must be accounted for as well. */
1383 account_process_tick(p, user_tick);
1385 rcu_check_callbacks(user_tick);
1386 #ifdef CONFIG_IRQ_WORK
1391 run_posix_cpu_timers(p);
1395 * This function runs timers and the timer-tq in bottom half context.
1397 static void run_timer_softirq(struct softirq_action *h)
1399 struct tvec_base *base = __this_cpu_read(tvec_bases);
1401 if (time_after_eq(jiffies, base->timer_jiffies))
1406 * Called by the local, per-CPU timer interrupt on SMP.
1408 void run_local_timers(void)
1410 hrtimer_run_queues();
1411 raise_softirq(TIMER_SOFTIRQ);
1414 #ifdef __ARCH_WANT_SYS_ALARM
1417 * For backwards compatibility? This can be done in libc so Alpha
1418 * and all newer ports shouldn't need it.
1420 SYSCALL_DEFINE1(alarm, unsigned int, seconds)
1422 return alarm_setitimer(seconds);
1427 static void process_timeout(unsigned long __data)
1429 wake_up_process((struct task_struct *)__data);
1433 * schedule_timeout - sleep until timeout
1434 * @timeout: timeout value in jiffies
1436 * Make the current task sleep until @timeout jiffies have
1437 * elapsed. The routine will return immediately unless
1438 * the current task state has been set (see set_current_state()).
1440 * You can set the task state as follows -
1442 * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
1443 * pass before the routine returns. The routine will return 0
1445 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1446 * delivered to the current task. In this case the remaining time
1447 * in jiffies will be returned, or 0 if the timer expired in time
1449 * The current task state is guaranteed to be TASK_RUNNING when this
1452 * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
1453 * the CPU away without a bound on the timeout. In this case the return
1454 * value will be %MAX_SCHEDULE_TIMEOUT.
1456 * In all cases the return value is guaranteed to be non-negative.
1458 signed long __sched schedule_timeout(signed long timeout)
1460 struct timer_list timer;
1461 unsigned long expire;
1465 case MAX_SCHEDULE_TIMEOUT:
1467 * These two special cases are useful to be comfortable
1468 * in the caller. Nothing more. We could take
1469 * MAX_SCHEDULE_TIMEOUT from one of the negative value
1470 * but I' d like to return a valid offset (>=0) to allow
1471 * the caller to do everything it want with the retval.
1477 * Another bit of PARANOID. Note that the retval will be
1478 * 0 since no piece of kernel is supposed to do a check
1479 * for a negative retval of schedule_timeout() (since it
1480 * should never happens anyway). You just have the printk()
1481 * that will tell you if something is gone wrong and where.
1484 printk(KERN_ERR "schedule_timeout: wrong timeout "
1485 "value %lx\n", timeout);
1487 current->state = TASK_RUNNING;
1492 expire = timeout + jiffies;
1494 setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
1495 __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
1497 del_singleshot_timer_sync(&timer);
1499 /* Remove the timer from the object tracker */
1500 destroy_timer_on_stack(&timer);
1502 timeout = expire - jiffies;
1505 return timeout < 0 ? 0 : timeout;
1507 EXPORT_SYMBOL(schedule_timeout);
1510 * We can use __set_current_state() here because schedule_timeout() calls
1511 * schedule() unconditionally.
1513 signed long __sched schedule_timeout_interruptible(signed long timeout)
1515 __set_current_state(TASK_INTERRUPTIBLE);
1516 return schedule_timeout(timeout);
1518 EXPORT_SYMBOL(schedule_timeout_interruptible);
1520 signed long __sched schedule_timeout_killable(signed long timeout)
1522 __set_current_state(TASK_KILLABLE);
1523 return schedule_timeout(timeout);
1525 EXPORT_SYMBOL(schedule_timeout_killable);
1527 signed long __sched schedule_timeout_uninterruptible(signed long timeout)
1529 __set_current_state(TASK_UNINTERRUPTIBLE);
1530 return schedule_timeout(timeout);
1532 EXPORT_SYMBOL(schedule_timeout_uninterruptible);
1534 #ifdef CONFIG_HOTPLUG_CPU
1535 static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
1537 struct timer_list *timer;
1539 while (!list_empty(head)) {
1540 timer = list_first_entry(head, struct timer_list, entry);
1541 /* We ignore the accounting on the dying cpu */
1542 detach_timer(timer, false);
1543 timer_set_base(timer, new_base);
1544 internal_add_timer(new_base, timer);
1548 static void migrate_timers(int cpu)
1550 struct tvec_base *old_base;
1551 struct tvec_base *new_base;
1554 BUG_ON(cpu_online(cpu));
1555 old_base = per_cpu(tvec_bases, cpu);
1556 new_base = get_cpu_var(tvec_bases);
1558 * The caller is globally serialized and nobody else
1559 * takes two locks at once, deadlock is not possible.
1561 spin_lock_irq(&new_base->lock);
1562 spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1564 BUG_ON(old_base->running_timer);
1566 for (i = 0; i < TVR_SIZE; i++)
1567 migrate_timer_list(new_base, old_base->tv1.vec + i);
1568 for (i = 0; i < TVN_SIZE; i++) {
1569 migrate_timer_list(new_base, old_base->tv2.vec + i);
1570 migrate_timer_list(new_base, old_base->tv3.vec + i);
1571 migrate_timer_list(new_base, old_base->tv4.vec + i);
1572 migrate_timer_list(new_base, old_base->tv5.vec + i);
1575 old_base->active_timers = 0;
1576 old_base->all_timers = 0;
1578 spin_unlock(&old_base->lock);
1579 spin_unlock_irq(&new_base->lock);
1580 put_cpu_var(tvec_bases);
1583 static int timer_cpu_notify(struct notifier_block *self,
1584 unsigned long action, void *hcpu)
1588 case CPU_DEAD_FROZEN:
1589 migrate_timers((long)hcpu);
1598 static inline void timer_register_cpu_notifier(void)
1600 cpu_notifier(timer_cpu_notify, 0);
1603 static inline void timer_register_cpu_notifier(void) { }
1604 #endif /* CONFIG_HOTPLUG_CPU */
1606 static void __init init_timer_cpu(struct tvec_base *base, int cpu)
1610 BUG_ON(base != tbase_get_base(base));
1613 per_cpu(tvec_bases, cpu) = base;
1614 spin_lock_init(&base->lock);
1616 for (j = 0; j < TVN_SIZE; j++) {
1617 INIT_LIST_HEAD(base->tv5.vec + j);
1618 INIT_LIST_HEAD(base->tv4.vec + j);
1619 INIT_LIST_HEAD(base->tv3.vec + j);
1620 INIT_LIST_HEAD(base->tv2.vec + j);
1622 for (j = 0; j < TVR_SIZE; j++)
1623 INIT_LIST_HEAD(base->tv1.vec + j);
1625 base->timer_jiffies = jiffies;
1626 base->next_timer = base->timer_jiffies;
1629 static void __init init_timer_cpus(void)
1631 struct tvec_base *base;
1632 int local_cpu = smp_processor_id();
1635 for_each_possible_cpu(cpu) {
1636 if (cpu == local_cpu)
1637 base = &boot_tvec_bases;
1640 base = per_cpu_ptr(&__tvec_bases, cpu);
1643 init_timer_cpu(base, cpu);
1647 void __init init_timers(void)
1649 /* ensure there are enough low bits for flags in timer->base pointer */
1650 BUILD_BUG_ON(__alignof__(struct tvec_base) & TIMER_FLAG_MASK);
1654 timer_register_cpu_notifier();
1655 open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
1659 * msleep - sleep safely even with waitqueue interruptions
1660 * @msecs: Time in milliseconds to sleep for
1662 void msleep(unsigned int msecs)
1664 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1667 timeout = schedule_timeout_uninterruptible(timeout);
1670 EXPORT_SYMBOL(msleep);
1673 * msleep_interruptible - sleep waiting for signals
1674 * @msecs: Time in milliseconds to sleep for
1676 unsigned long msleep_interruptible(unsigned int msecs)
1678 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1680 while (timeout && !signal_pending(current))
1681 timeout = schedule_timeout_interruptible(timeout);
1682 return jiffies_to_msecs(timeout);
1685 EXPORT_SYMBOL(msleep_interruptible);
1687 static void __sched do_usleep_range(unsigned long min, unsigned long max)
1690 unsigned long delta;
1692 kmin = ktime_set(0, min * NSEC_PER_USEC);
1693 delta = (max - min) * NSEC_PER_USEC;
1694 schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
1698 * usleep_range - Drop in replacement for udelay where wakeup is flexible
1699 * @min: Minimum time in usecs to sleep
1700 * @max: Maximum time in usecs to sleep
1702 void __sched usleep_range(unsigned long min, unsigned long max)
1704 __set_current_state(TASK_UNINTERRUPTIBLE);
1705 do_usleep_range(min, max);
1707 EXPORT_SYMBOL(usleep_range);