C++ enqueue_hrtimer函数代码示例

static void __run_hrtimer(struct hrtimer *timer)
{
	struct hrtimer_clock_base *base = timer->base;
	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
	enum hrtimer_restart (*fn)(struct hrtimer *);
	int restart;

	WARN_ON(!irqs_disabled());

	debug_hrtimer_deactivate(timer);
	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
	timer_stats_account_hrtimer(timer);
	fn = timer->function;

	/*
	 * Because we run timers from hardirq context, there is no chance
	 * they get migrated to another cpu, therefore its safe to unlock
	 * the timer base.
	 */
	spin_unlock(&cpu_base->lock);
	restart = fn(timer);
	spin_lock(&cpu_base->lock);

	/*
	 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
	 * we do not reprogramm the event hardware. Happens either in
	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
	 */
	if (restart != HRTIMER_NORESTART) {
		BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
		enqueue_hrtimer(timer, base);
	}
	timer->state &= ~HRTIMER_STATE_CALLBACK;
}

static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
				struct hrtimer_clock_base *new_base)
{
	struct hrtimer *timer;
	struct rb_node *node;

	while ((node = rb_first(&old_base->active))) {
		timer = rb_entry(node, struct hrtimer, node);
		BUG_ON(hrtimer_callback_running(timer));
		debug_hrtimer_deactivate(timer);

		/*
		 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
		 * timer could be seen as !active and just vanish away
		 * under us on another CPU
		 */
		__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
		timer->base = new_base;
		/*
		 * Enqueue the timers on the new cpu. This does not
		 * reprogram the event device in case the timer
		 * expires before the earliest on this CPU, but we run
		 * hrtimer_interrupt after we migrated everything to
		 * sort out already expired timers and reprogram the
		 * event device.
		 */
		enqueue_hrtimer(timer, new_base);

		/* Clear the migration state bit */
		timer->state &= ~HRTIMER_STATE_MIGRATE;
	}
}

static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
{
	struct hrtimer_clock_base *base = timer->base;
	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
	enum hrtimer_restart (*fn)(struct hrtimer *);
	int restart;

	WARN_ON(!irqs_disabled());

	debug_deactivate(timer);
	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
	timer_stats_account_hrtimer(timer);
	fn = timer->function;

	raw_spin_unlock(&cpu_base->lock);
	trace_hrtimer_expire_entry(timer, now);
	restart = fn(timer);
	trace_hrtimer_expire_exit(timer);
	raw_spin_lock(&cpu_base->lock);

	if (restart != HRTIMER_NORESTART) {
		BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
		enqueue_hrtimer(timer, base);
	}

	WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));

	timer->state &= ~HRTIMER_STATE_CALLBACK;
}

static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
				struct hrtimer_clock_base *new_base, int dcpu)
{
	struct hrtimer *timer;
	struct rb_node *node;
	int raise = 0;

	while ((node = rb_first(&old_base->active))) {
		timer = rb_entry(node, struct hrtimer, node);
		BUG_ON(hrtimer_callback_running(timer));
		debug_hrtimer_deactivate(timer);

		/*
		 * Should not happen. Per CPU timers should be
		 * canceled _before_ the migration code is called
		 */
		if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU) {
			__remove_hrtimer(timer, old_base,
					 HRTIMER_STATE_INACTIVE, 0);
			WARN(1, "hrtimer (%p %p)active but cpu %d dead\n",
			     timer, timer->function, dcpu);
			continue;
		}

		/*
		 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
		 * timer could be seen as !active and just vanish away
		 * under us on another CPU
		 */
		__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
		timer->base = new_base;
		/*
		 * Enqueue the timer. Allow reprogramming of the event device
		 */
		enqueue_hrtimer(timer, new_base, 1);

#ifdef CONFIG_HIGH_RES_TIMERS
		/*
		 * Happens with high res enabled when the timer was
		 * already expired and the callback mode is
		 * HRTIMER_CB_IRQSAFE_UNLOCKED (hrtimer_sleeper). The
		 * enqueue code does not move them to the soft irq
		 * pending list for performance/latency reasons, but
		 * in the migration state, we need to do that
		 * otherwise we end up with a stale timer.
		 */
		if (timer->state == HRTIMER_STATE_MIGRATE) {
			timer->state = HRTIMER_STATE_PENDING;
			list_add_tail(&timer->cb_entry,
				      &new_base->cpu_base->cb_pending);
			raise = 1;
		}
#endif
		/* Clear the migration state bit */
		timer->state &= ~HRTIMER_STATE_MIGRATE;
	}
	return raise;
}

/**
 * hrtimer_start - (re)start an relative timer on the current CPU
 * @timer:	the timer to be added
 * @tim:	expiry time
 * @mode:	expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
 *
 * Returns:
 *  0 on success
 *  1 when the timer was active
 */
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int ret, raise;

	base = lock_hrtimer_base(timer, &flags);

	/* Remove an active timer from the queue: */
	ret = remove_hrtimer(timer, base);

	/* Switch the timer base, if necessary: */
	new_base = switch_hrtimer_base(timer, base);

	if (mode == HRTIMER_MODE_REL) {
		tim = ktime_add_safe(tim, new_base->get_time());
		/*
		 * CONFIG_TIME_LOW_RES is a temporary way for architectures
		 * to signal that they simply return xtime in
		 * do_gettimeoffset(). In this case we want to round up by
		 * resolution when starting a relative timer, to avoid short
		 * timeouts. This will go away with the GTOD framework.
		 */
#ifdef CONFIG_TIME_LOW_RES
		tim = ktime_add_safe(tim, base->resolution);
#endif
	}

	timer->expires = tim;

	timer_stats_hrtimer_set_start_info(timer);

	/*
	 * Only allow reprogramming if the new base is on this CPU.
	 * (it might still be on another CPU if the timer was pending)
	 */
	enqueue_hrtimer(timer, new_base,
			new_base->cpu_base == &__get_cpu_var(hrtimer_bases));

	/*
	 * The timer may be expired and moved to the cb_pending
	 * list. We can not raise the softirq with base lock held due
	 * to a possible deadlock with runqueue lock.
	 */
	raise = timer->state == HRTIMER_STATE_PENDING;

	unlock_hrtimer_base(timer, &flags);

	if (raise)
		hrtimer_raise_softirq();

	return ret;
}

static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
{
	spin_lock_irq(&cpu_base->lock);

	while (!list_empty(&cpu_base->cb_pending)) {
		enum hrtimer_restart (*fn)(struct hrtimer *);
		struct hrtimer *timer;
		int restart;

		timer = list_entry(cpu_base->cb_pending.next,
				   struct hrtimer, cb_entry);

		debug_hrtimer_deactivate(timer);
		timer_stats_account_hrtimer(timer);

		fn = timer->function;
		__remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
		spin_unlock_irq(&cpu_base->lock);

		restart = fn(timer);

		spin_lock_irq(&cpu_base->lock);

		timer->state &= ~HRTIMER_STATE_CALLBACK;
		if (restart == HRTIMER_RESTART) {
			BUG_ON(hrtimer_active(timer));
			/*
			 * Enqueue the timer, allow reprogramming of the event
			 * device
			 */
			enqueue_hrtimer(timer, timer->base, 1);
		} else if (hrtimer_active(timer)) {
			/*
			 * If the timer was rearmed on another CPU, reprogram
			 * the event device.
			 */
			struct hrtimer_clock_base *base = timer->base;

			if (base->first == &timer->node &&
			    hrtimer_reprogram(timer, base)) {
				/*
				 * Timer is expired. Thus move it from tree to
				 * pending list again.
				 */
				__remove_hrtimer(timer, base,
						 HRTIMER_STATE_PENDING, 0);
				list_add_tail(&timer->cb_entry,
					      &base->cpu_base->cb_pending);
			}
		}
	}
	spin_unlock_irq(&cpu_base->lock);
}

/**
 * hrtimer_start - (re)start an relative timer on the current CPU
 * @timer:	the timer to be added
 * @tim:	expiry time
 * @mode:	expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
 *
 * Returns:
 *  0 on success
 *  1 when the timer was active
 */
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int ret;

	base = lock_hrtimer_base(timer, &flags);

	/* Remove an active timer from the queue: */
	ret = remove_hrtimer(timer, base);

	/* Switch the timer base, if necessary: */
	new_base = switch_hrtimer_base(timer, base);

	if (mode == HRTIMER_MODE_REL) {
		tim = ktime_add(tim, new_base->get_time());
		/*
		 * CONFIG_TIME_LOW_RES is a temporary way for architectures
		 * to signal that they simply return xtime in
		 * do_gettimeoffset(). In this case we want to round up by
		 * resolution when starting a relative timer, to avoid short
		 * timeouts. This will go away with the GTOD framework.
		 */
#ifdef CONFIG_TIME_LOW_RES
		tim = ktime_add(tim, base->resolution);
#endif
		/*
		 * Careful here: User space might have asked for a
		 * very long sleep, so the add above might result in a
		 * negative number, which enqueues the timer in front
		 * of the queue.
		 */
		if (tim.tv64 < 0)
			tim.tv64 = KTIME_MAX;
	}
	timer->expires = tim;

	timer_stats_hrtimer_set_start_info(timer);

	/*
	 * Only allow reprogramming if the new base is on this CPU.
	 * (it might still be on another CPU if the timer was pending)
	 */
	enqueue_hrtimer(timer, new_base,
			new_base->cpu_base == &__get_cpu_var(hrtimer_bases));

	unlock_hrtimer_base(timer, &flags);

	return ret;
}

/**
 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
 * @timer:	the timer to be added
 * @tim:	expiry time
 * @delta_ns:	"slack" range for the timer
 * @mode:	expiry mode: absolute (HRTIMER_MODE_ABS) or
 *		relative (HRTIMER_MODE_REL)
 */
void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
			    unsigned long delta_ns, const enum hrtimer_mode mode)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int leftmost;

	base = lock_hrtimer_base(timer, &flags);

	/* Remove an active timer from the queue: */
	remove_hrtimer(timer, base, true);

	if (mode & HRTIMER_MODE_REL) {
		tim = ktime_add_safe(tim, base->get_time());
		/*
		 * CONFIG_TIME_LOW_RES is a temporary way for architectures
		 * to signal that they simply return xtime in
		 * do_gettimeoffset(). In this case we want to round up by
		 * resolution when starting a relative timer, to avoid short
		 * timeouts. This will go away with the GTOD framework.
		 */
#ifdef CONFIG_TIME_LOW_RES
		tim = ktime_add_safe(tim, ktime_set(0, hrtimer_resolution));
#endif
	}

	hrtimer_set_expires_range_ns(timer, tim, delta_ns);

	/* Switch the timer base, if necessary: */
	new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

	timer_stats_hrtimer_set_start_info(timer);

	leftmost = enqueue_hrtimer(timer, new_base);
	if (!leftmost)
		goto unlock;

	if (!hrtimer_is_hres_active(timer)) {
		/*
		 * Kick to reschedule the next tick to handle the new timer
		 * on dynticks target.
		 */
		if (new_base->cpu_base->nohz_active)
			wake_up_nohz_cpu(new_base->cpu_base->cpu);
	} else {
		hrtimer_reprogram(timer, new_base);
	}
unlock:
	unlock_hrtimer_base(timer, &flags);
}

static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
{
	struct hrtimer_clock_base *base = timer->base;
	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
	enum hrtimer_restart (*fn)(struct hrtimer *);
	int restart;

	WARN_ON(!irqs_disabled());

	debug_deactivate(timer);
	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
	timer_stats_account_hrtimer(timer);
	fn = timer->function;

	/*
	 * Because we run timers from hardirq context, there is no chance
	 * they get migrated to another cpu, therefore its safe to unlock
	 * the timer base.
	 */
	raw_spin_unlock(&cpu_base->lock);
	trace_hrtimer_expire_entry(timer, now);
#ifdef CONFIG_SEC_DEBUG
	secdbg_msg("hrtimer %pS entry", fn);
#endif
	restart = fn(timer);
#ifdef CONFIG_SEC_DEBUG
	secdbg_msg("hrtimer %pS exit", fn);
#endif
	trace_hrtimer_expire_exit(timer);
	raw_spin_lock(&cpu_base->lock);

	/*
	 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
	 * we do not reprogramm the event hardware. Happens either in
	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
	 *
	 * Note: Because we dropped the cpu_base->lock above,
	 * hrtimer_start_range_ns() can have popped in and enqueued the timer
	 * for us already.
	 */
	if (restart != HRTIMER_NORESTART &&
	    !(timer->state & HRTIMER_STATE_ENQUEUED))
		enqueue_hrtimer(timer, base);

	WARN_ON_ONCE(!(timer->state & HRTIMER_STATE_CALLBACK));

	timer->state &= ~HRTIMER_STATE_CALLBACK;
}

static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
				struct hrtimer_clock_base *new_base)
{
	struct hrtimer *timer;
	struct rb_node *node;

	while ((node = rb_first(&old_base->active))) {
		timer = rb_entry(node, struct hrtimer, node);
		BUG_ON(hrtimer_callback_running(timer));
		__remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
		timer->base = new_base;
		/*
		 * Enqueue the timer. Allow reprogramming of the event device
		 */
		enqueue_hrtimer(timer, new_base, 1);
	}
}

int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
		unsigned long delta_ns, const enum hrtimer_mode mode,
		int wakeup)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int ret, leftmost;

	base = lock_hrtimer_base(timer, &flags);

	
	ret = remove_hrtimer(timer, base);

	
	new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

	if (mode & HRTIMER_MODE_REL) {
		tim = ktime_add_safe(tim, new_base->get_time());
#ifdef CONFIG_TIME_LOW_RES
		tim = ktime_add_safe(tim, base->resolution);
#endif
	}

	hrtimer_set_expires_range_ns(timer, tim, delta_ns);

	timer_stats_hrtimer_set_start_info(timer);

	leftmost = enqueue_hrtimer(timer, new_base);

	if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)
		&& hrtimer_enqueue_reprogram(timer, new_base)) {
		if (wakeup) {
			raw_spin_unlock(&new_base->cpu_base->lock);
			raise_softirq_irqoff(HRTIMER_SOFTIRQ);
			local_irq_restore(flags);
			return ret;
		} else {
			__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
		}
	}

	unlock_hrtimer_base(timer, &flags);

	return ret;
}

/*
 * Expire the per base hrtimer-queue:
 */
static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
				     int index)
{
	struct rb_node *node;
	struct hrtimer_clock_base *base = &cpu_base->clock_base[index];

	if (!base->first)
		return;

	if (base->get_softirq_time)
		base->softirq_time = base->get_softirq_time();

	spin_lock_irq(&cpu_base->lock);

	while ((node = base->first)) {
		struct hrtimer *timer;
		enum hrtimer_restart (*fn)(struct hrtimer *);
		int restart;

		timer = rb_entry(node, struct hrtimer, node);
		if (base->softirq_time.tv64 <= timer->expires.tv64)
			break;

#ifdef CONFIG_HIGH_RES_TIMERS
		WARN_ON_ONCE(timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ);
#endif
		timer_stats_account_hrtimer(timer);

		fn = timer->function;
		__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
		spin_unlock_irq(&cpu_base->lock);

		restart = fn(timer);

		spin_lock_irq(&cpu_base->lock);

		timer->state &= ~HRTIMER_STATE_CALLBACK;
		if (restart != HRTIMER_NORESTART) {
			BUG_ON(hrtimer_active(timer));
			enqueue_hrtimer(timer, base, 0);
		}
	}
	spin_unlock_irq(&cpu_base->lock);
}

static void run_hrtimer_softirq(struct softirq_action *h)
{
	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);

	spin_lock_irq(&cpu_base->lock);

	while (!list_empty(&cpu_base->cb_pending)) {
		enum hrtimer_restart (*fn)(struct hrtimer *);
		struct hrtimer *timer;
		int restart;

		timer = list_entry(cpu_base->cb_pending.next,
				   struct hrtimer, cb_entry);

		timer_stats_account_hrtimer(timer);

		fn = timer->function;
		__remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
		spin_unlock_irq(&cpu_base->lock);

		restart = fn(timer);

		spin_lock_irq(&cpu_base->lock);

		timer->state &= ~HRTIMER_STATE_CALLBACK;
		if (restart == HRTIMER_RESTART) {
			BUG_ON(hrtimer_active(timer));
			/*
			 * Enqueue the timer, allow reprogramming of the event
			 * device
			 */
			enqueue_hrtimer(timer, timer->base, 1);
		} else if (hrtimer_active(timer)) {
			/*
			 * If the timer was rearmed on another CPU, reprogram
			 * the event device.
			 */
			if (timer->base->first == &timer->node)
				hrtimer_reprogram(timer, timer->base);
		}
	}
	spin_unlock_irq(&cpu_base->lock);
}

/**
 * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
 * @timer:	the timer to be added
 * @tim:	expiry time
 * @delta_ns:	"slack" range for the timer
 * @mode:	expiry mode: absolute (HRTIMER_MODE_ABS) or
 *		relative (HRTIMER_MODE_REL)
 */
void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
			    u64 delta_ns, const enum hrtimer_mode mode)
{
	struct hrtimer_clock_base *base, *new_base;
	unsigned long flags;
	int leftmost;

	base = lock_hrtimer_base(timer, &flags);

	/* Remove an active timer from the queue: */
	remove_hrtimer(timer, base, true);

	if (mode & HRTIMER_MODE_REL)
		tim = ktime_add_safe(tim, base->get_time());

	tim = hrtimer_update_lowres(timer, tim, mode);

	hrtimer_set_expires_range_ns(timer, tim, delta_ns);

	/* Switch the timer base, if necessary: */
	new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);

	timer_stats_hrtimer_set_start_info(timer);

	leftmost = enqueue_hrtimer(timer, new_base);
	if (!leftmost)
		goto unlock;

	if (!hrtimer_is_hres_active(timer)) {
		/*
		 * Kick to reschedule the next tick to handle the new timer
		 * on dynticks target.
		 */
		if (new_base->cpu_base->nohz_active)
			wake_up_nohz_cpu(new_base->cpu_base->cpu);
	} else {
		hrtimer_reprogram(timer, new_base);
	}
unlock:
	unlock_hrtimer_base(timer, &flags);
}

static void __run_hrtimer(struct hrtimer *timer)
{
	struct hrtimer_clock_base *base = timer->base;
	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
	enum hrtimer_restart (*fn)(struct hrtimer *);
	int restart;

	debug_hrtimer_deactivate(timer);
	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
	timer_stats_account_hrtimer(timer);

	fn = timer->function;
	if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
	    timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) {
		/*
		 * Used for scheduler timers, avoid lock inversion with
		 * rq->lock and tasklist_lock.
		 *
		 * These timers are required to deal with enqueue expiry
		 * themselves and are not allowed to migrate.
		 */
		spin_unlock(&cpu_base->lock);
		restart = fn(timer);
		spin_lock(&cpu_base->lock);
	} else
		restart = fn(timer);

	/*
	 * Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid
	 * reprogramming of the event hardware. This happens at the end of this
	 * function anyway.
	 */
	if (restart != HRTIMER_NORESTART) {
		BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
		enqueue_hrtimer(timer, base, 0);
	}
	timer->state &= ~HRTIMER_STATE_CALLBACK;
}