按精确到期时间组织高精度定时器

20static inline bool __timerqueue_less(struct rb_node *a, const struct rb_node *b)21{22	return __node_2_tq(a)->expires < __node_2_tq(b)->expires;23}2425/**26 * timerqueue_add - Adds timer to timerqueue.27 *28 * @head: head of timerqueue29 * @node: timer node to be added30 *31 * Adds the timer node to the timerqueue, sorted by the node's expires32 * value. Returns true if the newly added timer is the first expiring timer in33 * the queue.34 */35bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)36{37	/* Make sure we don't add nodes that are already added */38	WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));3940	return rb_add_cached(&node->node, &head->rb_root, __timerqueue_less);41}

1073/*1074 * enqueue_hrtimer - internal function to (re)start a timer1075 *1076 * The timer is inserted in expiry order. Insertion into the1077 * red black tree is O(log(n)). Must hold the base lock.1078 *1079 * Returns 1 when the new timer is the leftmost timer in the tree.1080 */1081static int enqueue_hrtimer(struct hrtimer *timer,1082			   struct hrtimer_clock_base *base,1083			   enum hrtimer_mode mode)1084{1085	debug_activate(timer, mode);1086	WARN_ON_ONCE(!base->cpu_base->online);10871088	base->cpu_base->active_bases |= 1 << base->index;10891090	/* Pairs with the lockless read in hrtimer_is_queued() */1091	WRITE_ONCE(timer->state, HRTIMER_STATE_ENQUEUED);10921093	return timerqueue_add(&base->active, &timer->node);1094}