9  *  In contrast to the low-resolution timeout API, aka timer wheel,
16  *	Based on the original timer wheel code
41 #include <linux/timer.h>
47 #include <trace/events/timer.h>
61  * The timer bases:
64  * into the timer bases by the hrtimer_base_type enum. When trying
135  * timer->base->cpu_base
154  * means that all timers which are tied to this base via timer->base are
160  * When the timer's base is locked, and the timer removed from list, it is
161  * possible to set timer->base = &migration_base and drop the lock: the timer
165 struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,  in lock_hrtimer_base()  argument
171 		base = READ_ONCE(timer->base);  in lock_hrtimer_base()
174 			if (likely(base == timer->base))  in lock_hrtimer_base()
176 			/* The timer has migrated to another CPU: */  in lock_hrtimer_base()
184  * We do not migrate the timer when it is expiring before the next
193 hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)  in hrtimer_check_target()  argument
197 	expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);  in hrtimer_check_target()
213  * We switch the timer base to a power-optimized selected CPU target,
216  *	- timer migration is enabled
217  *	- the timer callback is not running
218  *	- the timer is not the first expiring timer on the new target
220  * If one of the above requirements is not fulfilled we move the timer
222  * the timer callback is currently running.
225 switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,  in switch_hrtimer_base()  argument
239 		 * We are trying to move timer to new_base.  in switch_hrtimer_base()
240 		 * However we can't change timer's base while it is running,  in switch_hrtimer_base()
243 		 * code will take care of this when the timer function has  in switch_hrtimer_base()
245 		 * the timer is enqueued.  in switch_hrtimer_base()
247 		if (unlikely(hrtimer_callback_running(timer)))  in switch_hrtimer_base()
251 		WRITE_ONCE(timer->base, &migration_base);  in switch_hrtimer_base()
256 		    hrtimer_check_target(timer, new_base)) {  in switch_hrtimer_base()
260 			WRITE_ONCE(timer->base, base);  in switch_hrtimer_base()
263 		WRITE_ONCE(timer->base, new_base);  in switch_hrtimer_base()
266 		    hrtimer_check_target(timer, new_base)) {  in switch_hrtimer_base()
282 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)  in lock_hrtimer_base()  argument
284 	struct hrtimer_clock_base *base = timer->base;  in lock_hrtimer_base()
358 	struct hrtimer *timer = addr;  in hrtimer_fixup_init()  local
362 		hrtimer_cancel(timer);  in hrtimer_fixup_init()
363 		debug_object_init(timer, &hrtimer_debug_descr);  in hrtimer_fixup_init()
392 	struct hrtimer *timer = addr;  in hrtimer_fixup_free()  local
396 		hrtimer_cancel(timer);  in hrtimer_fixup_free()
397 		debug_object_free(timer, &hrtimer_debug_descr);  in hrtimer_fixup_free()
412 static inline void debug_hrtimer_init(struct hrtimer *timer)  in debug_hrtimer_init()  argument
414 	debug_object_init(timer, &hrtimer_debug_descr);  in debug_hrtimer_init()
417 static inline void debug_hrtimer_activate(struct hrtimer *timer,  in debug_hrtimer_activate()  argument
420 	debug_object_activate(timer, &hrtimer_debug_descr);  in debug_hrtimer_activate()
423 static inline void debug_hrtimer_deactivate(struct hrtimer *timer)  in debug_hrtimer_deactivate()  argument
425 	debug_object_deactivate(timer, &hrtimer_debug_descr);  in debug_hrtimer_deactivate()
428 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
431 void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,  in hrtimer_init_on_stack()  argument
434 	debug_object_init_on_stack(timer, &hrtimer_debug_descr);  in hrtimer_init_on_stack()
435 	__hrtimer_init(timer, clock_id, mode);  in hrtimer_init_on_stack()
445 	debug_object_init_on_stack(&sl->timer, &hrtimer_debug_descr);  in hrtimer_init_sleeper_on_stack()
450 void destroy_hrtimer_on_stack(struct hrtimer *timer)  in destroy_hrtimer_on_stack()  argument
452 	debug_object_free(timer, &hrtimer_debug_descr);  in destroy_hrtimer_on_stack()
458 static inline void debug_hrtimer_init(struct hrtimer *timer) { }  in debug_hrtimer_init()  argument
459 static inline void debug_hrtimer_activate(struct hrtimer *timer,  in debug_hrtimer_activate()  argument
461 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }  in debug_hrtimer_deactivate()  argument
465 debug_init(struct hrtimer *timer, clockid_t clockid,  in debug_init()  argument
468 	debug_hrtimer_init(timer);  in debug_init()
469 	trace_hrtimer_init(timer, clockid, mode);  in debug_init()
472 static inline void debug_activate(struct hrtimer *timer,  in debug_activate()  argument
475 	debug_hrtimer_activate(timer, mode);  in debug_activate()
476 	trace_hrtimer_start(timer, mode);  in debug_activate()
479 static inline void debug_deactivate(struct hrtimer *timer)  in debug_deactivate()  argument
481 	debug_hrtimer_deactivate(timer);  in debug_deactivate()
482 	trace_hrtimer_cancel(timer);  in debug_deactivate()
512 		struct hrtimer *timer;  in __hrtimer_next_event_base()  local
515 		timer = container_of(next, struct hrtimer, node);  in __hrtimer_next_event_base()
516 		if (timer == exclude) {  in __hrtimer_next_event_base()
517 			/* Get to the next timer in the queue. */  in __hrtimer_next_event_base()
522 			timer = container_of(next, struct hrtimer, node);  in __hrtimer_next_event_base()
524 		expires = ktime_sub(hrtimer_get_expires(timer), base->offset);  in __hrtimer_next_event_base()
528 			/* Skip cpu_base update if a timer is being excluded. */  in __hrtimer_next_event_base()
532 			if (timer->is_soft)  in __hrtimer_next_event_base()
533 				cpu_base->softirq_next_timer = timer;  in __hrtimer_next_event_base()
535 				cpu_base->next_timer = timer;  in __hrtimer_next_event_base()
614 	 * If a softirq timer is expiring first, update cpu_base->next_timer  in hrtimer_update_next_event()
665 	 * If a hang was detected in the last timer interrupt then we  in __hrtimer_reprogram()
702 /* High resolution timer related functions */
706  * High resolution timer enabled ?
780 	 * If high resolution mode is active then the next expiring timer  in retrigger_next_event()
785 	 * of the next expiring timer is enough. The return from the SMP  in retrigger_next_event()
802  * When a timer is enqueued and expires earlier than the already enqueued
803  * timers, we have to check, whether it expires earlier than the timer for
808 static void hrtimer_reprogram(struct hrtimer *timer, bool reprogram)  in hrtimer_reprogram()  argument
811 	struct hrtimer_clock_base *base = timer->base;  in hrtimer_reprogram()
812 	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);  in hrtimer_reprogram()
814 	WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);  in hrtimer_reprogram()
817 	 * CLOCK_REALTIME timer might be requested with an absolute  in hrtimer_reprogram()
823 	if (timer->is_soft) {  in hrtimer_reprogram()
839 		timer_cpu_base->softirq_next_timer = timer;  in hrtimer_reprogram()
848 	 * If the timer is not on the current cpu, we cannot reprogram  in hrtimer_reprogram()
864 	cpu_base->next_timer = timer;  in hrtimer_reprogram()
866 	__hrtimer_reprogram(cpu_base, timer, expires);  in hrtimer_reprogram()
884 	 * the next expiring timer.  in update_needs_ipi()
898 	 * will reevaluate the first expiring timer of all clock bases  in update_needs_ipi()
906 	 * timer in a clock base is moving ahead of the first expiring timer of  in update_needs_ipi()
938  * when the change moves an affected timer ahead of the first expiring
939  * timer on that CPU. Obviously remote per CPU clock event devices cannot
1015 void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)  in unlock_hrtimer_base()  argument
1017 	raw_spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);  in unlock_hrtimer_base()
1021  * hrtimer_forward - forward the timer expiry
1022  * @timer:	hrtimer to forward
1026  * Forward the timer expiry so it will expire in the future.
1029  * Can be safely called from the callback function of @timer. If
1030  * called from other contexts @timer must neither be enqueued nor
1034  * Note: This only updates the timer expiry value and does not requeue
1035  * the timer.
1037 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)  in hrtimer_forward()  argument
1042 	delta = ktime_sub(now, hrtimer_get_expires(timer));  in hrtimer_forward()
1047 	if (WARN_ON(timer->state & HRTIMER_STATE_ENQUEUED))  in hrtimer_forward()
1057 		hrtimer_add_expires_ns(timer, incr * orun);  in hrtimer_forward()
1058 		if (hrtimer_get_expires_tv64(timer) > now)  in hrtimer_forward()
1066 	hrtimer_add_expires(timer, interval);  in hrtimer_forward()
1073  * enqueue_hrtimer - internal function to (re)start a timer
1075  * The timer is inserted in expiry order. Insertion into the
1078  * Returns 1 when the new timer is the leftmost timer in the tree.
1080 static int enqueue_hrtimer(struct hrtimer *timer,  in enqueue_hrtimer()  argument
1084 	debug_activate(timer, mode);  in enqueue_hrtimer()
1089 	WRITE_ONCE(timer->state, HRTIMER_STATE_ENQUEUED);  in enqueue_hrtimer()
1091 	return timerqueue_add(&base->active, &timer->node);  in enqueue_hrtimer()
1095  * __remove_hrtimer - internal function to remove a timer
1099  * High resolution timer mode reprograms the clock event device when the
1100  * timer is the one which expires next. The caller can disable this by setting
1102  * anyway (e.g. timer interrupt)
1104 static void __remove_hrtimer(struct hrtimer *timer,  in __remove_hrtimer()  argument
1109 	u8 state = timer->state;  in __remove_hrtimer()
1112 	WRITE_ONCE(timer->state, newstate);  in __remove_hrtimer()
1116 	if (!timerqueue_del(&base->active, &timer->node))  in __remove_hrtimer()
1122 	 * timer on a remote cpu. No harm as we never dereference  in __remove_hrtimer()
1125 	 * remote cpu later on if the same timer gets enqueued again.  in __remove_hrtimer()
1127 	if (reprogram && timer == cpu_base->next_timer)  in __remove_hrtimer()
1135 remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base,  in remove_hrtimer()  argument
1138 	u8 state = timer->state;  in remove_hrtimer()
1144 		 * Remove the timer and force reprogramming when high  in remove_hrtimer()
1145 		 * resolution mode is active and the timer is on the current  in remove_hrtimer()
1146 		 * CPU. If we remove a timer on another CPU, reprogramming is  in remove_hrtimer()
1151 		debug_deactivate(timer);  in remove_hrtimer()
1155 		 * If the timer is not restarted then reprogramming is  in remove_hrtimer()
1156 		 * required if the timer is local. If it is local and about  in remove_hrtimer()
1165 		__remove_hrtimer(timer, base, state, reprogram);  in remove_hrtimer()
1171 static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim,  in hrtimer_update_lowres()  argument
1180 	timer->is_rel = mode & HRTIMER_MODE_REL;  in hrtimer_update_lowres()
1181 	if (timer->is_rel)  in hrtimer_update_lowres()
1212 static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,  in __hrtimer_start_range_ns()  argument
1220 	 * If the timer is on the local cpu base and is the first expiring  in __hrtimer_start_range_ns()
1221 	 * timer then this might end up reprogramming the hardware twice  in __hrtimer_start_range_ns()
1223 	 * reprogram on removal, keep the timer local to the current CPU  in __hrtimer_start_range_ns()
1225 	 * it is the new first expiring timer again or not.  in __hrtimer_start_range_ns()
1228 	force_local &= base->cpu_base->next_timer == timer;  in __hrtimer_start_range_ns()
1231 	 * Remove an active timer from the queue. In case it is not queued  in __hrtimer_start_range_ns()
1235 	 * If it's on the current CPU and the first expiring timer, then  in __hrtimer_start_range_ns()
1236 	 * skip reprogramming, keep the timer local and enforce  in __hrtimer_start_range_ns()
1237 	 * reprogramming later if it was the first expiring timer.  This  in __hrtimer_start_range_ns()
1241 	remove_hrtimer(timer, base, true, force_local);  in __hrtimer_start_range_ns()
1246 	tim = hrtimer_update_lowres(timer, tim, mode);  in __hrtimer_start_range_ns()
1248 	hrtimer_set_expires_range_ns(timer, tim, delta_ns);  in __hrtimer_start_range_ns()
1250 	/* Switch the timer base, if necessary: */  in __hrtimer_start_range_ns()
1252 		new_base = switch_hrtimer_base(timer, base,  in __hrtimer_start_range_ns()
1258 	first = enqueue_hrtimer(timer, new_base, mode);  in __hrtimer_start_range_ns()
1263 	 * Timer was forced to stay on the current CPU to avoid  in __hrtimer_start_range_ns()
1265 	 * hardware by evaluating the new first expiring timer.  in __hrtimer_start_range_ns()
1273  * @timer:	the timer to be added
1275  * @delta_ns:	"slack" range for the timer
1276  * @mode:	timer mode: absolute (HRTIMER_MODE_ABS) or
1280 void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,  in hrtimer_start_range_ns()  argument
1292 		WARN_ON_ONCE(!(mode & HRTIMER_MODE_SOFT) ^ !timer->is_soft);  in hrtimer_start_range_ns()
1294 		WARN_ON_ONCE(!(mode & HRTIMER_MODE_HARD) ^ !timer->is_hard);  in hrtimer_start_range_ns()
1296 	base = lock_hrtimer_base(timer, &flags);  in hrtimer_start_range_ns()
1298 	if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))  in hrtimer_start_range_ns()
1299 		hrtimer_reprogram(timer, true);  in hrtimer_start_range_ns()
1301 	unlock_hrtimer_base(timer, &flags);  in hrtimer_start_range_ns()
1306  * hrtimer_try_to_cancel - try to deactivate a timer
1307  * @timer:	hrtimer to stop
1311  *  *  0 when the timer was not active
1312  *  *  1 when the timer was active
1313  *  * -1 when the timer is currently executing the callback function and
1316 int hrtimer_try_to_cancel(struct hrtimer *timer)  in hrtimer_try_to_cancel()  argument
1323 	 * Check lockless first. If the timer is not active (neither  in hrtimer_try_to_cancel()
1328 	if (!hrtimer_active(timer))  in hrtimer_try_to_cancel()
1331 	base = lock_hrtimer_base(timer, &flags);  in hrtimer_try_to_cancel()
1333 	if (!hrtimer_callback_running(timer))  in hrtimer_try_to_cancel()
1334 		ret = remove_hrtimer(timer, base, false, false);  in hrtimer_try_to_cancel()
1336 	unlock_hrtimer_base(timer, &flags);  in hrtimer_try_to_cancel()
1363  * the timer callback to finish. Drop expiry_lock and reacquire it. That
1379  * deletion of a timer failed because the timer callback function was
1383  * in the middle of a timer callback, then calling del_timer_sync() can
1386  *  - If the caller is on a remote CPU then it has to spin wait for the timer
1389  *  - If the caller originates from the task which preempted the timer
1390  *    handler on the same CPU, then spin waiting for the timer handler to
1393 void hrtimer_cancel_wait_running(const struct hrtimer *timer)  in hrtimer_cancel_wait_running()  argument
1396 	struct hrtimer_clock_base *base = READ_ONCE(timer->base);  in hrtimer_cancel_wait_running()
1399 	 * Just relax if the timer expires in hard interrupt context or if  in hrtimer_cancel_wait_running()
1402 	if (!timer->is_soft || is_migration_base(base)) {  in hrtimer_cancel_wait_running()
1409 	 * held by the softirq across the timer callback. Drop the lock  in hrtimer_cancel_wait_running()
1410 	 * immediately so the softirq can expire the next timer. In theory  in hrtimer_cancel_wait_running()
1411 	 * the timer could already be running again, but that's more than  in hrtimer_cancel_wait_running()
1431  * hrtimer_cancel - cancel a timer and wait for the handler to finish.
1432  * @timer:	the timer to be cancelled
1435  *  0 when the timer was not active
1436  *  1 when the timer was active
1438 int hrtimer_cancel(struct hrtimer *timer)  in hrtimer_cancel()  argument
1443 		ret = hrtimer_try_to_cancel(timer);  in hrtimer_cancel()
1446 			hrtimer_cancel_wait_running(timer);  in hrtimer_cancel()
1453  * __hrtimer_get_remaining - get remaining time for the timer
1454  * @timer:	the timer to read
1457 ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust)  in __hrtimer_get_remaining()  argument
1462 	lock_hrtimer_base(timer, &flags);  in __hrtimer_get_remaining()
1464 		rem = hrtimer_expires_remaining_adjusted(timer);  in __hrtimer_get_remaining()
1466 		rem = hrtimer_expires_remaining(timer);  in __hrtimer_get_remaining()
1467 	unlock_hrtimer_base(timer, &flags);  in __hrtimer_get_remaining()
1477  * Returns the next expiry time or KTIME_MAX if no timer is pending.
1496  * hrtimer_next_event_without - time until next expiry event w/o one timer
1497  * @exclude:	timer to exclude
1541 static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,  in __hrtimer_init()  argument
1557 	memset(timer, 0, sizeof(struct hrtimer));  in __hrtimer_init()
1571 	timer->is_soft = softtimer;  in __hrtimer_init()
1572 	timer->is_hard = !!(mode & HRTIMER_MODE_HARD);  in __hrtimer_init()
1573 	timer->base = &cpu_base->clock_base[base];  in __hrtimer_init()
1574 	timerqueue_init(&timer->node);  in __hrtimer_init()
1578  * hrtimer_init - initialize a timer to the given clock
1579  * @timer:	the timer to be initialized
1589 void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,  in hrtimer_init()  argument
1592 	debug_init(timer, clock_id, mode);  in hrtimer_init()
1593 	__hrtimer_init(timer, clock_id, mode);  in hrtimer_init()
1598  * A timer is active, when it is enqueued into the rbtree or the
1604 bool hrtimer_active(const struct hrtimer *timer)  in hrtimer_active()  argument
1610 		base = READ_ONCE(timer->base);  in hrtimer_active()
1613 		if (timer->state != HRTIMER_STATE_INACTIVE ||  in hrtimer_active()
1614 		    base->running == timer)  in hrtimer_active()
1618 		 base != READ_ONCE(timer->base));  in hrtimer_active()
1628  *  - queued:	the timer is queued
1629  *  - callback:	the timer is being ran
1630  *  - post:	the timer is inactive or (re)queued
1632  * On the read side we ensure we observe timer->state and cpu_base->running
1634  * This includes timer->base changing because sequence numbers alone are
1644 			  struct hrtimer *timer, ktime_t *now,  in __run_hrtimer()  argument
1653 	debug_deactivate(timer);  in __run_hrtimer()
1654 	base->running = timer;  in __run_hrtimer()
1661 	 * timer->state == INACTIVE.  in __run_hrtimer()
1665 	__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);  in __run_hrtimer()
1666 	fn = timer->function;  in __run_hrtimer()
1670 	 * timer is restarted with a period then it becomes an absolute  in __run_hrtimer()
1671 	 * timer. If its not restarted it does not matter.  in __run_hrtimer()
1674 		timer->is_rel = false;  in __run_hrtimer()
1677 	 * The timer is marked as running in the CPU base, so it is  in __run_hrtimer()
1682 	trace_hrtimer_expire_entry(timer, now);  in __run_hrtimer()
1683 	expires_in_hardirq = lockdep_hrtimer_enter(timer);  in __run_hrtimer()
1685 	restart = fn(timer);  in __run_hrtimer()
1688 	trace_hrtimer_expire_exit(timer);  in __run_hrtimer()
1697 	 * hrtimer_start_range_ns() can have popped in and enqueued the timer  in __run_hrtimer()
1701 	    !(timer->state & HRTIMER_STATE_ENQUEUED))  in __run_hrtimer()
1702 		enqueue_hrtimer(timer, base, HRTIMER_MODE_ABS);  in __run_hrtimer()
1708 	 * hrtimer_active() cannot observe base->running.timer == NULL &&  in __run_hrtimer()
1709 	 * timer->state == INACTIVE.  in __run_hrtimer()
1713 	WARN_ON_ONCE(base->running != timer);  in __run_hrtimer()
1730 			struct hrtimer *timer;  in __hrtimer_run_queues()  local
1732 			timer = container_of(node, struct hrtimer, node);  in __hrtimer_run_queues()
1743 			 * are right-of a not yet expired timer, because that  in __hrtimer_run_queues()
1744 			 * timer will have to trigger a wakeup anyway.  in __hrtimer_run_queues()
1746 			if (basenow < hrtimer_get_softexpires_tv64(timer))  in __hrtimer_run_queues()
1749 			__run_hrtimer(cpu_base, base, timer, &basenow, flags);  in __hrtimer_run_queues()
1778  * High resolution timer interrupt
1798 	 * held to prevent that a timer is enqueued in our queue via  in hrtimer_interrupt()
1830 	 * The next timer was already expired due to:  in hrtimer_interrupt()
1931 static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)  in hrtimer_wakeup()  argument
1934 		container_of(timer, struct hrtimer_sleeper, timer);  in hrtimer_wakeup()
1945  * hrtimer_sleeper_start_expires - Start a hrtimer sleeper timer
1947  * @mode:	timer mode abs/rel
1962 	if (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)  in hrtimer_sleeper_start_expires()
1965 	hrtimer_start_expires(&sl->timer, mode);  in hrtimer_sleeper_start_expires()
1996 	__hrtimer_init(&sl->timer, clock_id, mode);  in __hrtimer_init_sleeper()
1997 	sl->timer.function = hrtimer_wakeup;  in __hrtimer_init_sleeper()
2005  * @mode:	timer mode abs/rel
2010 	debug_init(&sl->timer, clock_id, mode);  in hrtimer_init_sleeper()
2046 		hrtimer_cancel(&t->timer);  in do_nanosleep()
2058 		ktime_t rem = hrtimer_expires_remaining(&t->timer);  in do_nanosleep()
2077 	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);  in hrtimer_nanosleep_restart()
2079 	destroy_hrtimer_on_stack(&t.timer);  in hrtimer_nanosleep_restart()
2096 	hrtimer_set_expires_range_ns(&t.timer, rqtp, slack);  in hrtimer_nanosleep()
2108 	restart->nanosleep.clockid = t.timer.base->clockid;  in hrtimer_nanosleep()
2109 	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);  in hrtimer_nanosleep()
2112 	destroy_hrtimer_on_stack(&t.timer);  in hrtimer_nanosleep()
2190 	struct hrtimer *timer;  in migrate_hrtimer_list()  local
2194 		timer = container_of(node, struct hrtimer, node);  in migrate_hrtimer_list()
2195 		BUG_ON(hrtimer_callback_running(timer));  in migrate_hrtimer_list()
2196 		debug_deactivate(timer);  in migrate_hrtimer_list()
2200 		 * timer could be seen as !active and just vanish away  in migrate_hrtimer_list()
2203 		__remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0);  in migrate_hrtimer_list()
2204 		timer->base = new_base;  in migrate_hrtimer_list()
2207 		 * reprogram the event device in case the timer  in migrate_hrtimer_list()
2213 		enqueue_hrtimer(timer, new_base, HRTIMER_MODE_ABS);  in migrate_hrtimer_list()
2248 	 * timer on this CPU. Update it.  in hrtimers_dead_cpu()
2274  * @mode:	timer mode
2275  * @clock_id:	timer clock to be used
2301 	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);  in schedule_hrtimeout_range_clock()
2307 	hrtimer_cancel(&t.timer);  in schedule_hrtimeout_range_clock()
2308 	destroy_hrtimer_on_stack(&t.timer);  in schedule_hrtimeout_range_clock()
2319  * @mode:	timer mode
2328  * but may decide to fire the timer earlier, but no earlier than @expires.
2343  * Returns 0 when the timer has expired. If the task was woken before the
2344  * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or
2358  * @mode:	timer mode
2377  * Returns 0 when the timer has expired. If the task was woken before the
2378  * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or