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/module.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/perf_event.h>
41 #include <linux/sched.h>
42 #include <linux/slab.h>
44 #include <asm/uaccess.h>
45 #include <asm/unistd.h>
46 #include <asm/div64.h>
47 #include <asm/timex.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/timer.h>
53 u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
55 EXPORT_SYMBOL(jiffies_64);
58 * per-CPU timer vector definitions:
60 #define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
61 #define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
62 #define TVN_SIZE (1 << TVN_BITS)
63 #define TVR_SIZE (1 << TVR_BITS)
64 #define TVN_MASK (TVN_SIZE - 1)
65 #define TVR_MASK (TVR_SIZE - 1)
68 struct list_head vec[TVN_SIZE];
72 struct list_head vec[TVR_SIZE];
77 struct timer_list *running_timer;
78 unsigned long timer_jiffies;
79 unsigned long next_timer;
85 } ____cacheline_aligned;
87 struct tvec_base boot_tvec_bases;
88 EXPORT_SYMBOL(boot_tvec_bases);
89 static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
92 * Note that all tvec_bases are 2 byte aligned and lower bit of
93 * base in timer_list is guaranteed to be zero. Use the LSB to
94 * indicate whether the timer is deferrable.
96 * A deferrable timer will work normally when the system is busy, but
97 * will not cause a CPU to come out of idle just to service it; instead,
98 * the timer will be serviced when the CPU eventually wakes up with a
99 * subsequent non-deferrable timer.
101 #define TBASE_DEFERRABLE_FLAG (0x1)
103 /* Functions below help us manage 'deferrable' flag */
104 static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
106 return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
109 static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
111 return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));
114 static inline void timer_set_deferrable(struct timer_list *timer)
116 timer->base = ((struct tvec_base *)((unsigned long)(timer->base) |
117 TBASE_DEFERRABLE_FLAG));
121 timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
123 timer->base = (struct tvec_base *)((unsigned long)(new_base) |
124 tbase_get_deferrable(timer->base));
127 static unsigned long round_jiffies_common(unsigned long j, int cpu,
131 unsigned long original = j;
134 * We don't want all cpus firing their timers at once hitting the
135 * same lock or cachelines, so we skew each extra cpu with an extra
136 * 3 jiffies. This 3 jiffies came originally from the mm/ code which
138 * The skew is done by adding 3*cpunr, then round, then subtract this
139 * extra offset again.
146 * If the target jiffie is just after a whole second (which can happen
147 * due to delays of the timer irq, long irq off times etc etc) then
148 * we should round down to the whole second, not up. Use 1/4th second
149 * as cutoff for this rounding as an extreme upper bound for this.
150 * But never round down if @force_up is set.
152 if (rem < HZ/4 && !force_up) /* round down */
157 /* now that we have rounded, subtract the extra skew again */
160 if (j <= jiffies) /* rounding ate our timeout entirely; */
166 * __round_jiffies - function to round jiffies to a full second
167 * @j: the time in (absolute) jiffies that should be rounded
168 * @cpu: the processor number on which the timeout will happen
170 * __round_jiffies() rounds an absolute time in the future (in jiffies)
171 * up or down to (approximately) full seconds. This is useful for timers
172 * for which the exact time they fire does not matter too much, as long as
173 * they fire approximately every X seconds.
175 * By rounding these timers to whole seconds, all such timers will fire
176 * at the same time, rather than at various times spread out. The goal
177 * of this is to have the CPU wake up less, which saves power.
179 * The exact rounding is skewed for each processor to avoid all
180 * processors firing at the exact same time, which could lead
181 * to lock contention or spurious cache line bouncing.
183 * The return value is the rounded version of the @j parameter.
185 unsigned long __round_jiffies(unsigned long j, int cpu)
187 return round_jiffies_common(j, cpu, false);
189 EXPORT_SYMBOL_GPL(__round_jiffies);
192 * __round_jiffies_relative - function to round jiffies to a full second
193 * @j: the time in (relative) jiffies that should be rounded
194 * @cpu: the processor number on which the timeout will happen
196 * __round_jiffies_relative() rounds a time delta in the future (in jiffies)
197 * up or down to (approximately) full seconds. This is useful for timers
198 * for which the exact time they fire does not matter too much, as long as
199 * they fire approximately every X seconds.
201 * By rounding these timers to whole seconds, all such timers will fire
202 * at the same time, rather than at various times spread out. The goal
203 * of this is to have the CPU wake up less, which saves power.
205 * The exact rounding is skewed for each processor to avoid all
206 * processors firing at the exact same time, which could lead
207 * to lock contention or spurious cache line bouncing.
209 * The return value is the rounded version of the @j parameter.
211 unsigned long __round_jiffies_relative(unsigned long j, int cpu)
213 unsigned long j0 = jiffies;
215 /* Use j0 because jiffies might change while we run */
216 return round_jiffies_common(j + j0, cpu, false) - j0;
218 EXPORT_SYMBOL_GPL(__round_jiffies_relative);
221 * round_jiffies - function to round jiffies to a full second
222 * @j: the time in (absolute) jiffies that should be rounded
224 * round_jiffies() rounds an absolute time in the future (in jiffies)
225 * up or down to (approximately) full seconds. This is useful for timers
226 * for which the exact time they fire does not matter too much, as long as
227 * they fire approximately every X seconds.
229 * By rounding these timers to whole seconds, all such timers will fire
230 * at the same time, rather than at various times spread out. The goal
231 * of this is to have the CPU wake up less, which saves power.
233 * The return value is the rounded version of the @j parameter.
235 unsigned long round_jiffies(unsigned long j)
237 return round_jiffies_common(j, raw_smp_processor_id(), false);
239 EXPORT_SYMBOL_GPL(round_jiffies);
242 * round_jiffies_relative - function to round jiffies to a full second
243 * @j: the time in (relative) jiffies that should be rounded
245 * round_jiffies_relative() rounds a time delta in the future (in jiffies)
246 * up or down to (approximately) full seconds. This is useful for timers
247 * for which the exact time they fire does not matter too much, as long as
248 * they fire approximately every X seconds.
250 * By rounding these timers to whole seconds, all such timers will fire
251 * at the same time, rather than at various times spread out. The goal
252 * of this is to have the CPU wake up less, which saves power.
254 * The return value is the rounded version of the @j parameter.
256 unsigned long round_jiffies_relative(unsigned long j)
258 return __round_jiffies_relative(j, raw_smp_processor_id());
260 EXPORT_SYMBOL_GPL(round_jiffies_relative);
263 * __round_jiffies_up - function to round jiffies up to a full second
264 * @j: the time in (absolute) jiffies that should be rounded
265 * @cpu: the processor number on which the timeout will happen
267 * This is the same as __round_jiffies() except that it will never
268 * round down. This is useful for timeouts for which the exact time
269 * of firing does not matter too much, as long as they don't fire too
272 unsigned long __round_jiffies_up(unsigned long j, int cpu)
274 return round_jiffies_common(j, cpu, true);
276 EXPORT_SYMBOL_GPL(__round_jiffies_up);
279 * __round_jiffies_up_relative - function to round jiffies up to a full second
280 * @j: the time in (relative) jiffies that should be rounded
281 * @cpu: the processor number on which the timeout will happen
283 * This is the same as __round_jiffies_relative() except that it will never
284 * round down. This is useful for timeouts for which the exact time
285 * of firing does not matter too much, as long as they don't fire too
288 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
290 unsigned long j0 = jiffies;
292 /* Use j0 because jiffies might change while we run */
293 return round_jiffies_common(j + j0, cpu, true) - j0;
295 EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);
298 * round_jiffies_up - function to round jiffies up to a full second
299 * @j: the time in (absolute) jiffies that should be rounded
301 * This is the same as round_jiffies() except that it will never
302 * round down. This is useful for timeouts for which the exact time
303 * of firing does not matter too much, as long as they don't fire too
306 unsigned long round_jiffies_up(unsigned long j)
308 return round_jiffies_common(j, raw_smp_processor_id(), true);
310 EXPORT_SYMBOL_GPL(round_jiffies_up);
313 * round_jiffies_up_relative - function to round jiffies up to a full second
314 * @j: the time in (relative) jiffies that should be rounded
316 * This is the same as round_jiffies_relative() except that it will never
317 * round down. This is useful for timeouts for which the exact time
318 * of firing does not matter too much, as long as they don't fire too
321 unsigned long round_jiffies_up_relative(unsigned long j)
323 return __round_jiffies_up_relative(j, raw_smp_processor_id());
325 EXPORT_SYMBOL_GPL(round_jiffies_up_relative);
328 * set_timer_slack - set the allowed slack for a timer
329 * @slack_hz: the amount of time (in jiffies) allowed for rounding
331 * Set the amount of time, in jiffies, that a certain timer has
332 * in terms of slack. By setting this value, the timer subsystem
333 * will schedule the actual timer somewhere between
334 * the time mod_timer() asks for, and that time plus the slack.
336 * By setting the slack to -1, a percentage of the delay is used
339 void set_timer_slack(struct timer_list *timer, int slack_hz)
341 timer->slack = slack_hz;
343 EXPORT_SYMBOL_GPL(set_timer_slack);
346 static inline void set_running_timer(struct tvec_base *base,
347 struct timer_list *timer)
350 base->running_timer = timer;
354 static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
356 unsigned long expires = timer->expires;
357 unsigned long idx = expires - base->timer_jiffies;
358 struct list_head *vec;
360 if (idx < TVR_SIZE) {
361 int i = expires & TVR_MASK;
362 vec = base->tv1.vec + i;
363 } else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
364 int i = (expires >> TVR_BITS) & TVN_MASK;
365 vec = base->tv2.vec + i;
366 } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
367 int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
368 vec = base->tv3.vec + i;
369 } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
370 int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
371 vec = base->tv4.vec + i;
372 } else if ((signed long) idx < 0) {
374 * Can happen if you add a timer with expires == jiffies,
375 * or you set a timer to go off in the past
377 vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
380 /* If the timeout is larger than 0xffffffff on 64-bit
381 * architectures then we use the maximum timeout:
383 if (idx > 0xffffffffUL) {
385 expires = idx + base->timer_jiffies;
387 i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
388 vec = base->tv5.vec + i;
393 list_add_tail(&timer->entry, vec);
396 #ifdef CONFIG_TIMER_STATS
397 void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
399 if (timer->start_site)
402 timer->start_site = addr;
403 memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
404 timer->start_pid = current->pid;
407 static void timer_stats_account_timer(struct timer_list *timer)
409 unsigned int flag = 0;
411 if (likely(!timer->start_site))
413 if (unlikely(tbase_get_deferrable(timer->base)))
414 flag |= TIMER_STATS_FLAG_DEFERRABLE;
416 timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
417 timer->function, timer->start_comm, flag);
421 static void timer_stats_account_timer(struct timer_list *timer) {}
424 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
426 static struct debug_obj_descr timer_debug_descr;
429 * fixup_init is called when:
430 * - an active object is initialized
432 static int timer_fixup_init(void *addr, enum debug_obj_state state)
434 struct timer_list *timer = addr;
437 case ODEBUG_STATE_ACTIVE:
438 del_timer_sync(timer);
439 debug_object_init(timer, &timer_debug_descr);
447 * fixup_activate is called when:
448 * - an active object is activated
449 * - an unknown object is activated (might be a statically initialized object)
451 static int timer_fixup_activate(void *addr, enum debug_obj_state state)
453 struct timer_list *timer = addr;
457 case ODEBUG_STATE_NOTAVAILABLE:
459 * This is not really a fixup. The timer was
460 * statically initialized. We just make sure that it
461 * is tracked in the object tracker.
463 if (timer->entry.next == NULL &&
464 timer->entry.prev == TIMER_ENTRY_STATIC) {
465 debug_object_init(timer, &timer_debug_descr);
466 debug_object_activate(timer, &timer_debug_descr);
473 case ODEBUG_STATE_ACTIVE:
482 * fixup_free is called when:
483 * - an active object is freed
485 static int timer_fixup_free(void *addr, enum debug_obj_state state)
487 struct timer_list *timer = addr;
490 case ODEBUG_STATE_ACTIVE:
491 del_timer_sync(timer);
492 debug_object_free(timer, &timer_debug_descr);
499 static struct debug_obj_descr timer_debug_descr = {
500 .name = "timer_list",
501 .fixup_init = timer_fixup_init,
502 .fixup_activate = timer_fixup_activate,
503 .fixup_free = timer_fixup_free,
506 static inline void debug_timer_init(struct timer_list *timer)
508 debug_object_init(timer, &timer_debug_descr);
511 static inline void debug_timer_activate(struct timer_list *timer)
513 debug_object_activate(timer, &timer_debug_descr);
516 static inline void debug_timer_deactivate(struct timer_list *timer)
518 debug_object_deactivate(timer, &timer_debug_descr);
521 static inline void debug_timer_free(struct timer_list *timer)
523 debug_object_free(timer, &timer_debug_descr);
526 static void __init_timer(struct timer_list *timer,
528 struct lock_class_key *key);
530 void init_timer_on_stack_key(struct timer_list *timer,
532 struct lock_class_key *key)
534 debug_object_init_on_stack(timer, &timer_debug_descr);
535 __init_timer(timer, name, key);
537 EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
539 void destroy_timer_on_stack(struct timer_list *timer)
541 debug_object_free(timer, &timer_debug_descr);
543 EXPORT_SYMBOL_GPL(destroy_timer_on_stack);
546 static inline void debug_timer_init(struct timer_list *timer) { }
547 static inline void debug_timer_activate(struct timer_list *timer) { }
548 static inline void debug_timer_deactivate(struct timer_list *timer) { }
551 static inline void debug_init(struct timer_list *timer)
553 debug_timer_init(timer);
554 trace_timer_init(timer);
558 debug_activate(struct timer_list *timer, unsigned long expires)
560 debug_timer_activate(timer);
561 trace_timer_start(timer, expires);
564 static inline void debug_deactivate(struct timer_list *timer)
566 debug_timer_deactivate(timer);
567 trace_timer_cancel(timer);
570 static void __init_timer(struct timer_list *timer,
572 struct lock_class_key *key)
574 timer->entry.next = NULL;
575 timer->base = __raw_get_cpu_var(tvec_bases);
577 #ifdef CONFIG_TIMER_STATS
578 timer->start_site = NULL;
579 timer->start_pid = -1;
580 memset(timer->start_comm, 0, TASK_COMM_LEN);
582 lockdep_init_map(&timer->lockdep_map, name, key, 0);
586 * init_timer_key - initialize a timer
587 * @timer: the timer to be initialized
588 * @name: name of the timer
589 * @key: lockdep class key of the fake lock used for tracking timer
590 * sync lock dependencies
592 * init_timer_key() must be done to a timer prior calling *any* of the
593 * other timer functions.
595 void init_timer_key(struct timer_list *timer,
597 struct lock_class_key *key)
600 __init_timer(timer, name, key);
602 EXPORT_SYMBOL(init_timer_key);
604 void init_timer_deferrable_key(struct timer_list *timer,
606 struct lock_class_key *key)
608 init_timer_key(timer, name, key);
609 timer_set_deferrable(timer);
611 EXPORT_SYMBOL(init_timer_deferrable_key);
613 static inline void detach_timer(struct timer_list *timer,
616 struct list_head *entry = &timer->entry;
618 debug_deactivate(timer);
620 __list_del(entry->prev, entry->next);
623 entry->prev = LIST_POISON2;
627 * We are using hashed locking: holding per_cpu(tvec_bases).lock
628 * means that all timers which are tied to this base via timer->base are
629 * locked, and the base itself is locked too.
631 * So __run_timers/migrate_timers can safely modify all timers which could
632 * be found on ->tvX lists.
634 * When the timer's base is locked, and the timer removed from list, it is
635 * possible to set timer->base = NULL and drop the lock: the timer remains
638 static struct tvec_base *lock_timer_base(struct timer_list *timer,
639 unsigned long *flags)
640 __acquires(timer->base->lock)
642 struct tvec_base *base;
645 struct tvec_base *prelock_base = timer->base;
646 base = tbase_get_base(prelock_base);
647 if (likely(base != NULL)) {
648 spin_lock_irqsave(&base->lock, *flags);
649 if (likely(prelock_base == timer->base))
651 /* The timer has migrated to another CPU */
652 spin_unlock_irqrestore(&base->lock, *flags);
659 __mod_timer(struct timer_list *timer, unsigned long expires,
660 bool pending_only, int pinned)
662 struct tvec_base *base, *new_base;
666 timer_stats_timer_set_start_info(timer);
667 BUG_ON(!timer->function);
669 base = lock_timer_base(timer, &flags);
671 if (timer_pending(timer)) {
672 detach_timer(timer, 0);
673 if (timer->expires == base->next_timer &&
674 !tbase_get_deferrable(timer->base))
675 base->next_timer = base->timer_jiffies;
682 debug_activate(timer, expires);
684 cpu = smp_processor_id();
686 #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
687 if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) {
688 int preferred_cpu = get_nohz_load_balancer();
690 if (preferred_cpu >= 0)
694 new_base = per_cpu(tvec_bases, cpu);
696 if (base != new_base) {
698 * We are trying to schedule the timer on the local CPU.
699 * However we can't change timer's base while it is running,
700 * otherwise del_timer_sync() can't detect that the timer's
701 * handler yet has not finished. This also guarantees that
702 * the timer is serialized wrt itself.
704 if (likely(base->running_timer != timer)) {
705 /* See the comment in lock_timer_base() */
706 timer_set_base(timer, NULL);
707 spin_unlock(&base->lock);
709 spin_lock(&base->lock);
710 timer_set_base(timer, base);
714 timer->expires = expires;
715 if (time_before(timer->expires, base->next_timer) &&
716 !tbase_get_deferrable(timer->base))
717 base->next_timer = timer->expires;
718 internal_add_timer(base, timer);
721 spin_unlock_irqrestore(&base->lock, flags);
727 * mod_timer_pending - modify a pending timer's timeout
728 * @timer: the pending timer to be modified
729 * @expires: new timeout in jiffies
731 * mod_timer_pending() is the same for pending timers as mod_timer(),
732 * but will not re-activate and modify already deleted timers.
734 * It is useful for unserialized use of timers.
736 int mod_timer_pending(struct timer_list *timer, unsigned long expires)
738 return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
740 EXPORT_SYMBOL(mod_timer_pending);
743 * Decide where to put the timer while taking the slack into account
746 * 1) calculate the maximum (absolute) time
747 * 2) calculate the highest bit where the expires and new max are different
748 * 3) use this bit to make a mask
749 * 4) use the bitmask to round down the maximum time, so that all last
753 unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
755 unsigned long expires_limit, mask;
758 expires_limit = expires;
760 if (timer->slack >= 0) {
761 expires_limit = expires + timer->slack;
763 unsigned long now = jiffies;
765 /* No slack, if already expired else auto slack 0.4% */
766 if (time_after(expires, now))
767 expires_limit = expires + (expires - now)/256;
769 mask = expires ^ expires_limit;
773 bit = find_last_bit(&mask, BITS_PER_LONG);
775 mask = (1 << bit) - 1;
777 expires_limit = expires_limit & ~(mask);
779 return expires_limit;
783 * mod_timer - modify a timer's timeout
784 * @timer: the timer to be modified
785 * @expires: new timeout in jiffies
787 * mod_timer() is a more efficient way to update the expire field of an
788 * active timer (if the timer is inactive it will be activated)
790 * mod_timer(timer, expires) is equivalent to:
792 * del_timer(timer); timer->expires = expires; add_timer(timer);
794 * Note that if there are multiple unserialized concurrent users of the
795 * same timer, then mod_timer() is the only safe way to modify the timeout,
796 * since add_timer() cannot modify an already running timer.
798 * The function returns whether it has modified a pending timer or not.
799 * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
800 * active timer returns 1.)
802 int mod_timer(struct timer_list *timer, unsigned long expires)
805 * This is a common optimization triggered by the
806 * networking code - if the timer is re-modified
807 * to be the same thing then just return:
809 if (timer_pending(timer) && timer->expires == expires)
812 expires = apply_slack(timer, expires);
814 return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
816 EXPORT_SYMBOL(mod_timer);
819 * mod_timer_pinned - modify a timer's timeout
820 * @timer: the timer to be modified
821 * @expires: new timeout in jiffies
823 * mod_timer_pinned() is a way to update the expire field of an
824 * active timer (if the timer is inactive it will be activated)
825 * and not allow the timer to be migrated to a different CPU.
827 * mod_timer_pinned(timer, expires) is equivalent to:
829 * del_timer(timer); timer->expires = expires; add_timer(timer);
831 int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
833 if (timer->expires == expires && timer_pending(timer))
836 return __mod_timer(timer, expires, false, TIMER_PINNED);
838 EXPORT_SYMBOL(mod_timer_pinned);
841 * add_timer - start a timer
842 * @timer: the timer to be added
844 * The kernel will do a ->function(->data) callback from the
845 * timer interrupt at the ->expires point in the future. The
846 * current time is 'jiffies'.
848 * The timer's ->expires, ->function (and if the handler uses it, ->data)
849 * fields must be set prior calling this function.
851 * Timers with an ->expires field in the past will be executed in the next
854 void add_timer(struct timer_list *timer)
856 BUG_ON(timer_pending(timer));
857 mod_timer(timer, timer->expires);
859 EXPORT_SYMBOL(add_timer);
862 * add_timer_on - start a timer on a particular CPU
863 * @timer: the timer to be added
864 * @cpu: the CPU to start it on
866 * This is not very scalable on SMP. Double adds are not possible.
868 void add_timer_on(struct timer_list *timer, int cpu)
870 struct tvec_base *base = per_cpu(tvec_bases, cpu);
873 timer_stats_timer_set_start_info(timer);
874 BUG_ON(timer_pending(timer) || !timer->function);
875 spin_lock_irqsave(&base->lock, flags);
876 timer_set_base(timer, base);
877 debug_activate(timer, timer->expires);
878 if (time_before(timer->expires, base->next_timer) &&
879 !tbase_get_deferrable(timer->base))
880 base->next_timer = timer->expires;
881 internal_add_timer(base, timer);
883 * Check whether the other CPU is idle and needs to be
884 * triggered to reevaluate the timer wheel when nohz is
885 * active. We are protected against the other CPU fiddling
886 * with the timer by holding the timer base lock. This also
887 * makes sure that a CPU on the way to idle can not evaluate
890 wake_up_idle_cpu(cpu);
891 spin_unlock_irqrestore(&base->lock, flags);
893 EXPORT_SYMBOL_GPL(add_timer_on);
896 * del_timer - deactive a timer.
897 * @timer: the timer to be deactivated
899 * del_timer() deactivates a timer - this works on both active and inactive
902 * The function returns whether it has deactivated a pending timer or not.
903 * (ie. del_timer() of an inactive timer returns 0, del_timer() of an
904 * active timer returns 1.)
906 int del_timer(struct timer_list *timer)
908 struct tvec_base *base;
912 timer_stats_timer_clear_start_info(timer);
913 if (timer_pending(timer)) {
914 base = lock_timer_base(timer, &flags);
915 if (timer_pending(timer)) {
916 detach_timer(timer, 1);
917 if (timer->expires == base->next_timer &&
918 !tbase_get_deferrable(timer->base))
919 base->next_timer = base->timer_jiffies;
922 spin_unlock_irqrestore(&base->lock, flags);
927 EXPORT_SYMBOL(del_timer);
931 * try_to_del_timer_sync - Try to deactivate a timer
932 * @timer: timer do del
934 * This function tries to deactivate a timer. Upon successful (ret >= 0)
935 * exit the timer is not queued and the handler is not running on any CPU.
937 * It must not be called from interrupt contexts.
939 int try_to_del_timer_sync(struct timer_list *timer)
941 struct tvec_base *base;
945 base = lock_timer_base(timer, &flags);
947 if (base->running_timer == timer)
950 timer_stats_timer_clear_start_info(timer);
952 if (timer_pending(timer)) {
953 detach_timer(timer, 1);
954 if (timer->expires == base->next_timer &&
955 !tbase_get_deferrable(timer->base))
956 base->next_timer = base->timer_jiffies;
960 spin_unlock_irqrestore(&base->lock, flags);
964 EXPORT_SYMBOL(try_to_del_timer_sync);
967 * del_timer_sync - deactivate a timer and wait for the handler to finish.
968 * @timer: the timer to be deactivated
970 * This function only differs from del_timer() on SMP: besides deactivating
971 * the timer it also makes sure the handler has finished executing on other
974 * Synchronization rules: Callers must prevent restarting of the timer,
975 * otherwise this function is meaningless. It must not be called from
976 * interrupt contexts. The caller must not hold locks which would prevent
977 * completion of the timer's handler. The timer's handler must not call
978 * add_timer_on(). Upon exit the timer is not queued and the handler is
979 * not running on any CPU.
981 * The function returns whether it has deactivated a pending timer or not.
983 int del_timer_sync(struct timer_list *timer)
985 #ifdef CONFIG_LOCKDEP
988 local_irq_save(flags);
989 lock_map_acquire(&timer->lockdep_map);
990 lock_map_release(&timer->lockdep_map);
991 local_irq_restore(flags);
995 int ret = try_to_del_timer_sync(timer);
1001 EXPORT_SYMBOL(del_timer_sync);
1004 static int cascade(struct tvec_base *base, struct tvec *tv, int index)
1006 /* cascade all the timers from tv up one level */
1007 struct timer_list *timer, *tmp;
1008 struct list_head tv_list;
1010 list_replace_init(tv->vec + index, &tv_list);
1013 * We are removing _all_ timers from the list, so we
1014 * don't have to detach them individually.
1016 list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
1017 BUG_ON(tbase_get_base(timer->base) != base);
1018 internal_add_timer(base, timer);
1024 static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
1027 int preempt_count = preempt_count();
1029 #ifdef CONFIG_LOCKDEP
1031 * It is permissible to free the timer from inside the
1032 * function that is called from it, this we need to take into
1033 * account for lockdep too. To avoid bogus "held lock freed"
1034 * warnings as well as problems when looking into
1035 * timer->lockdep_map, make a copy and use that here.
1037 struct lockdep_map lockdep_map = timer->lockdep_map;
1040 * Couple the lock chain with the lock chain at
1041 * del_timer_sync() by acquiring the lock_map around the fn()
1042 * call here and in del_timer_sync().
1044 lock_map_acquire(&lockdep_map);
1046 trace_timer_expire_entry(timer);
1048 trace_timer_expire_exit(timer);
1050 lock_map_release(&lockdep_map);
1052 if (preempt_count != preempt_count()) {
1053 WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
1054 fn, preempt_count, preempt_count());
1056 * Restore the preempt count. That gives us a decent
1057 * chance to survive and extract information. If the
1058 * callback kept a lock held, bad luck, but not worse
1059 * than the BUG() we had.
1061 preempt_count() = preempt_count;
1065 #define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)
1068 * __run_timers - run all expired timers (if any) on this CPU.
1069 * @base: the timer vector to be processed.
1071 * This function cascades all vectors and executes all expired timer
1074 static inline void __run_timers(struct tvec_base *base)
1076 struct timer_list *timer;
1078 spin_lock_irq(&base->lock);
1079 while (time_after_eq(jiffies, base->timer_jiffies)) {
1080 struct list_head work_list;
1081 struct list_head *head = &work_list;
1082 int index = base->timer_jiffies & TVR_MASK;
1088 (!cascade(base, &base->tv2, INDEX(0))) &&
1089 (!cascade(base, &base->tv3, INDEX(1))) &&
1090 !cascade(base, &base->tv4, INDEX(2)))
1091 cascade(base, &base->tv5, INDEX(3));
1092 ++base->timer_jiffies;
1093 list_replace_init(base->tv1.vec + index, &work_list);
1094 while (!list_empty(head)) {
1095 void (*fn)(unsigned long);
1098 timer = list_first_entry(head, struct timer_list,entry);
1099 fn = timer->function;
1102 timer_stats_account_timer(timer);
1104 set_running_timer(base, timer);
1105 detach_timer(timer, 1);
1107 spin_unlock_irq(&base->lock);
1108 call_timer_fn(timer, fn, data);
1109 spin_lock_irq(&base->lock);
1112 set_running_timer(base, NULL);
1113 spin_unlock_irq(&base->lock);
1118 * Find out when the next timer event is due to happen. This
1119 * is used on S/390 to stop all activity when a CPU is idle.
1120 * This function needs to be called with interrupts disabled.
1122 static unsigned long __next_timer_interrupt(struct tvec_base *base)
1124 unsigned long timer_jiffies = base->timer_jiffies;
1125 unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
1126 int index, slot, array, found = 0;
1127 struct timer_list *nte;
1128 struct tvec *varray[4];
1130 /* Look for timer events in tv1. */
1131 index = slot = timer_jiffies & TVR_MASK;
1133 list_for_each_entry(nte, base->tv1.vec + slot, entry) {
1134 if (tbase_get_deferrable(nte->base))
1138 expires = nte->expires;
1139 /* Look at the cascade bucket(s)? */
1140 if (!index || slot < index)
1144 slot = (slot + 1) & TVR_MASK;
1145 } while (slot != index);
1148 /* Calculate the next cascade event */
1150 timer_jiffies += TVR_SIZE - index;
1151 timer_jiffies >>= TVR_BITS;
1153 /* Check tv2-tv5. */
1154 varray[0] = &base->tv2;
1155 varray[1] = &base->tv3;
1156 varray[2] = &base->tv4;
1157 varray[3] = &base->tv5;
1159 for (array = 0; array < 4; array++) {
1160 struct tvec *varp = varray[array];
1162 index = slot = timer_jiffies & TVN_MASK;
1164 list_for_each_entry(nte, varp->vec + slot, entry) {
1165 if (tbase_get_deferrable(nte->base))
1169 if (time_before(nte->expires, expires))
1170 expires = nte->expires;
1173 * Do we still search for the first timer or are
1174 * we looking up the cascade buckets ?
1177 /* Look at the cascade bucket(s)? */
1178 if (!index || slot < index)
1182 slot = (slot + 1) & TVN_MASK;
1183 } while (slot != index);
1186 timer_jiffies += TVN_SIZE - index;
1187 timer_jiffies >>= TVN_BITS;
1193 * Check, if the next hrtimer event is before the next timer wheel
1196 static unsigned long cmp_next_hrtimer_event(unsigned long now,
1197 unsigned long expires)
1199 ktime_t hr_delta = hrtimer_get_next_event();
1200 struct timespec tsdelta;
1201 unsigned long delta;
1203 if (hr_delta.tv64 == KTIME_MAX)
1207 * Expired timer available, let it expire in the next tick
1209 if (hr_delta.tv64 <= 0)
1212 tsdelta = ktime_to_timespec(hr_delta);
1213 delta = timespec_to_jiffies(&tsdelta);
1216 * Limit the delta to the max value, which is checked in
1217 * tick_nohz_stop_sched_tick():
1219 if (delta > NEXT_TIMER_MAX_DELTA)
1220 delta = NEXT_TIMER_MAX_DELTA;
1223 * Take rounding errors in to account and make sure, that it
1224 * expires in the next tick. Otherwise we go into an endless
1225 * ping pong due to tick_nohz_stop_sched_tick() retriggering
1231 if (time_before(now, expires))
1237 * get_next_timer_interrupt - return the jiffy of the next pending timer
1238 * @now: current time (in jiffies)
1240 unsigned long get_next_timer_interrupt(unsigned long now)
1242 struct tvec_base *base = __get_cpu_var(tvec_bases);
1243 unsigned long expires;
1245 spin_lock(&base->lock);
1246 if (time_before_eq(base->next_timer, base->timer_jiffies))
1247 base->next_timer = __next_timer_interrupt(base);
1248 expires = base->next_timer;
1249 spin_unlock(&base->lock);
1251 if (time_before_eq(expires, now))
1254 return cmp_next_hrtimer_event(now, expires);
1259 * Called from the timer interrupt handler to charge one tick to the current
1260 * process. user_tick is 1 if the tick is user time, 0 for system.
1262 void update_process_times(int user_tick)
1264 struct task_struct *p = current;
1265 int cpu = smp_processor_id();
1267 /* Note: this timer irq context must be accounted for as well. */
1268 account_process_tick(p, user_tick);
1270 rcu_check_callbacks(cpu, user_tick);
1272 perf_event_do_pending();
1274 run_posix_cpu_timers(p);
1278 * This function runs timers and the timer-tq in bottom half context.
1280 static void run_timer_softirq(struct softirq_action *h)
1282 struct tvec_base *base = __get_cpu_var(tvec_bases);
1284 hrtimer_run_pending();
1286 if (time_after_eq(jiffies, base->timer_jiffies))
1291 * Called by the local, per-CPU timer interrupt on SMP.
1293 void run_local_timers(void)
1295 hrtimer_run_queues();
1296 raise_softirq(TIMER_SOFTIRQ);
1301 * The 64-bit jiffies value is not atomic - you MUST NOT read it
1302 * without sampling the sequence number in xtime_lock.
1303 * jiffies is defined in the linker script...
1306 void do_timer(unsigned long ticks)
1308 jiffies_64 += ticks;
1313 #ifdef __ARCH_WANT_SYS_ALARM
1316 * For backwards compatibility? This can be done in libc so Alpha
1317 * and all newer ports shouldn't need it.
1319 SYSCALL_DEFINE1(alarm, unsigned int, seconds)
1321 return alarm_setitimer(seconds);
1329 * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
1330 * should be moved into arch/i386 instead?
1334 * sys_getpid - return the thread group id of the current process
1336 * Note, despite the name, this returns the tgid not the pid. The tgid and
1337 * the pid are identical unless CLONE_THREAD was specified on clone() in
1338 * which case the tgid is the same in all threads of the same group.
1340 * This is SMP safe as current->tgid does not change.
1342 SYSCALL_DEFINE0(getpid)
1344 return task_tgid_vnr(current);
1348 * Accessing ->real_parent is not SMP-safe, it could
1349 * change from under us. However, we can use a stale
1350 * value of ->real_parent under rcu_read_lock(), see
1351 * release_task()->call_rcu(delayed_put_task_struct).
1353 SYSCALL_DEFINE0(getppid)
1358 pid = task_tgid_vnr(current->real_parent);
1364 SYSCALL_DEFINE0(getuid)
1366 /* Only we change this so SMP safe */
1367 return current_uid();
1370 SYSCALL_DEFINE0(geteuid)
1372 /* Only we change this so SMP safe */
1373 return current_euid();
1376 SYSCALL_DEFINE0(getgid)
1378 /* Only we change this so SMP safe */
1379 return current_gid();
1382 SYSCALL_DEFINE0(getegid)
1384 /* Only we change this so SMP safe */
1385 return current_egid();
1390 static void process_timeout(unsigned long __data)
1392 wake_up_process((struct task_struct *)__data);
1396 * schedule_timeout - sleep until timeout
1397 * @timeout: timeout value in jiffies
1399 * Make the current task sleep until @timeout jiffies have
1400 * elapsed. The routine will return immediately unless
1401 * the current task state has been set (see set_current_state()).
1403 * You can set the task state as follows -
1405 * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
1406 * pass before the routine returns. The routine will return 0
1408 * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
1409 * delivered to the current task. In this case the remaining time
1410 * in jiffies will be returned, or 0 if the timer expired in time
1412 * The current task state is guaranteed to be TASK_RUNNING when this
1415 * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
1416 * the CPU away without a bound on the timeout. In this case the return
1417 * value will be %MAX_SCHEDULE_TIMEOUT.
1419 * In all cases the return value is guaranteed to be non-negative.
1421 signed long __sched schedule_timeout(signed long timeout)
1423 struct timer_list timer;
1424 unsigned long expire;
1428 case MAX_SCHEDULE_TIMEOUT:
1430 * These two special cases are useful to be comfortable
1431 * in the caller. Nothing more. We could take
1432 * MAX_SCHEDULE_TIMEOUT from one of the negative value
1433 * but I' d like to return a valid offset (>=0) to allow
1434 * the caller to do everything it want with the retval.
1440 * Another bit of PARANOID. Note that the retval will be
1441 * 0 since no piece of kernel is supposed to do a check
1442 * for a negative retval of schedule_timeout() (since it
1443 * should never happens anyway). You just have the printk()
1444 * that will tell you if something is gone wrong and where.
1447 printk(KERN_ERR "schedule_timeout: wrong timeout "
1448 "value %lx\n", timeout);
1450 current->state = TASK_RUNNING;
1455 expire = timeout + jiffies;
1457 setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
1458 __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
1460 del_singleshot_timer_sync(&timer);
1462 /* Remove the timer from the object tracker */
1463 destroy_timer_on_stack(&timer);
1465 timeout = expire - jiffies;
1468 return timeout < 0 ? 0 : timeout;
1470 EXPORT_SYMBOL(schedule_timeout);
1473 * We can use __set_current_state() here because schedule_timeout() calls
1474 * schedule() unconditionally.
1476 signed long __sched schedule_timeout_interruptible(signed long timeout)
1478 __set_current_state(TASK_INTERRUPTIBLE);
1479 return schedule_timeout(timeout);
1481 EXPORT_SYMBOL(schedule_timeout_interruptible);
1483 signed long __sched schedule_timeout_killable(signed long timeout)
1485 __set_current_state(TASK_KILLABLE);
1486 return schedule_timeout(timeout);
1488 EXPORT_SYMBOL(schedule_timeout_killable);
1490 signed long __sched schedule_timeout_uninterruptible(signed long timeout)
1492 __set_current_state(TASK_UNINTERRUPTIBLE);
1493 return schedule_timeout(timeout);
1495 EXPORT_SYMBOL(schedule_timeout_uninterruptible);
1497 /* Thread ID - the internal kernel "pid" */
1498 SYSCALL_DEFINE0(gettid)
1500 return task_pid_vnr(current);
1504 * do_sysinfo - fill in sysinfo struct
1505 * @info: pointer to buffer to fill
1507 int do_sysinfo(struct sysinfo *info)
1509 unsigned long mem_total, sav_total;
1510 unsigned int mem_unit, bitcount;
1513 memset(info, 0, sizeof(struct sysinfo));
1516 monotonic_to_bootbased(&tp);
1517 info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
1519 get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
1521 info->procs = nr_threads;
1527 * If the sum of all the available memory (i.e. ram + swap)
1528 * is less than can be stored in a 32 bit unsigned long then
1529 * we can be binary compatible with 2.2.x kernels. If not,
1530 * well, in that case 2.2.x was broken anyways...
1532 * -Erik Andersen <andersee@debian.org>
1535 mem_total = info->totalram + info->totalswap;
1536 if (mem_total < info->totalram || mem_total < info->totalswap)
1539 mem_unit = info->mem_unit;
1540 while (mem_unit > 1) {
1543 sav_total = mem_total;
1545 if (mem_total < sav_total)
1550 * If mem_total did not overflow, multiply all memory values by
1551 * info->mem_unit and set it to 1. This leaves things compatible
1552 * with 2.2.x, and also retains compatibility with earlier 2.4.x
1557 info->totalram <<= bitcount;
1558 info->freeram <<= bitcount;
1559 info->sharedram <<= bitcount;
1560 info->bufferram <<= bitcount;
1561 info->totalswap <<= bitcount;
1562 info->freeswap <<= bitcount;
1563 info->totalhigh <<= bitcount;
1564 info->freehigh <<= bitcount;
1570 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
1576 if (copy_to_user(info, &val, sizeof(struct sysinfo)))
1582 static int __cpuinit init_timers_cpu(int cpu)
1585 struct tvec_base *base;
1586 static char __cpuinitdata tvec_base_done[NR_CPUS];
1588 if (!tvec_base_done[cpu]) {
1589 static char boot_done;
1593 * The APs use this path later in boot
1595 base = kmalloc_node(sizeof(*base),
1596 GFP_KERNEL | __GFP_ZERO,
1601 /* Make sure that tvec_base is 2 byte aligned */
1602 if (tbase_get_deferrable(base)) {
1607 per_cpu(tvec_bases, cpu) = base;
1610 * This is for the boot CPU - we use compile-time
1611 * static initialisation because per-cpu memory isn't
1612 * ready yet and because the memory allocators are not
1613 * initialised either.
1616 base = &boot_tvec_bases;
1618 tvec_base_done[cpu] = 1;
1620 base = per_cpu(tvec_bases, cpu);
1623 spin_lock_init(&base->lock);
1625 for (j = 0; j < TVN_SIZE; j++) {
1626 INIT_LIST_HEAD(base->tv5.vec + j);
1627 INIT_LIST_HEAD(base->tv4.vec + j);
1628 INIT_LIST_HEAD(base->tv3.vec + j);
1629 INIT_LIST_HEAD(base->tv2.vec + j);
1631 for (j = 0; j < TVR_SIZE; j++)
1632 INIT_LIST_HEAD(base->tv1.vec + j);
1634 base->timer_jiffies = jiffies;
1635 base->next_timer = base->timer_jiffies;
1639 #ifdef CONFIG_HOTPLUG_CPU
1640 static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
1642 struct timer_list *timer;
1644 while (!list_empty(head)) {
1645 timer = list_first_entry(head, struct timer_list, entry);
1646 detach_timer(timer, 0);
1647 timer_set_base(timer, new_base);
1648 if (time_before(timer->expires, new_base->next_timer) &&
1649 !tbase_get_deferrable(timer->base))
1650 new_base->next_timer = timer->expires;
1651 internal_add_timer(new_base, timer);
1655 static void __cpuinit migrate_timers(int cpu)
1657 struct tvec_base *old_base;
1658 struct tvec_base *new_base;
1661 BUG_ON(cpu_online(cpu));
1662 old_base = per_cpu(tvec_bases, cpu);
1663 new_base = get_cpu_var(tvec_bases);
1665 * The caller is globally serialized and nobody else
1666 * takes two locks at once, deadlock is not possible.
1668 spin_lock_irq(&new_base->lock);
1669 spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
1671 BUG_ON(old_base->running_timer);
1673 for (i = 0; i < TVR_SIZE; i++)
1674 migrate_timer_list(new_base, old_base->tv1.vec + i);
1675 for (i = 0; i < TVN_SIZE; i++) {
1676 migrate_timer_list(new_base, old_base->tv2.vec + i);
1677 migrate_timer_list(new_base, old_base->tv3.vec + i);
1678 migrate_timer_list(new_base, old_base->tv4.vec + i);
1679 migrate_timer_list(new_base, old_base->tv5.vec + i);
1682 spin_unlock(&old_base->lock);
1683 spin_unlock_irq(&new_base->lock);
1684 put_cpu_var(tvec_bases);
1686 #endif /* CONFIG_HOTPLUG_CPU */
1688 static int __cpuinit timer_cpu_notify(struct notifier_block *self,
1689 unsigned long action, void *hcpu)
1691 long cpu = (long)hcpu;
1695 case CPU_UP_PREPARE:
1696 case CPU_UP_PREPARE_FROZEN:
1697 err = init_timers_cpu(cpu);
1699 return notifier_from_errno(err);
1701 #ifdef CONFIG_HOTPLUG_CPU
1703 case CPU_DEAD_FROZEN:
1704 migrate_timers(cpu);
1713 static struct notifier_block __cpuinitdata timers_nb = {
1714 .notifier_call = timer_cpu_notify,
1718 void __init init_timers(void)
1720 int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
1721 (void *)(long)smp_processor_id());
1725 BUG_ON(err != NOTIFY_OK);
1726 register_cpu_notifier(&timers_nb);
1727 open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
1731 * msleep - sleep safely even with waitqueue interruptions
1732 * @msecs: Time in milliseconds to sleep for
1734 void msleep(unsigned int msecs)
1736 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1739 timeout = schedule_timeout_uninterruptible(timeout);
1742 EXPORT_SYMBOL(msleep);
1745 * msleep_interruptible - sleep waiting for signals
1746 * @msecs: Time in milliseconds to sleep for
1748 unsigned long msleep_interruptible(unsigned int msecs)
1750 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
1752 while (timeout && !signal_pending(current))
1753 timeout = schedule_timeout_interruptible(timeout);
1754 return jiffies_to_msecs(timeout);
1757 EXPORT_SYMBOL(msleep_interruptible);
1759 static int __sched do_usleep_range(unsigned long min, unsigned long max)
1762 unsigned long delta;
1764 kmin = ktime_set(0, min * NSEC_PER_USEC);
1766 return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
1770 * usleep_range - Drop in replacement for udelay where wakeup is flexible
1771 * @min: Minimum time in usecs to sleep
1772 * @max: Maximum time in usecs to sleep
1774 void usleep_range(unsigned long min, unsigned long max)
1776 __set_current_state(TASK_UNINTERRUPTIBLE);
1777 do_usleep_range(min, max);
1779 EXPORT_SYMBOL(usleep_range);