让大量普通超时按时间槽批量到期

567static inline unsigned calc_index(unsigned long expires, unsigned lvl,568				  unsigned long *bucket_expiry)569{570571	/*572	 * The timer wheel has to guarantee that a timer does not fire573	 * early. Early expiry can happen due to:574	 * - Timer is armed at the edge of a tick575	 * - Truncation of the expiry time in the outer wheel levels576	 *577	 * Round up with level granularity to prevent this.578	 */579	expires = (expires >> LVL_SHIFT(lvl)) + 1;580	*bucket_expiry = expires << LVL_SHIFT(lvl);581	return LVL_OFFS(lvl) + (expires & LVL_MASK);582}

584static int calc_wheel_index(unsigned long expires, unsigned long clk,585			    unsigned long *bucket_expiry)586{587	unsigned long delta = expires - clk;588	unsigned int idx;589590	if (delta < LVL_START(1)) {591		idx = calc_index(expires, 0, bucket_expiry);592	} else if (delta < LVL_START(2)) {593		idx = calc_index(expires, 1, bucket_expiry);594	} else if (delta < LVL_START(3)) {595		idx = calc_index(expires, 2, bucket_expiry);596	} else if (delta < LVL_START(4)) {597		idx = calc_index(expires, 3, bucket_expiry);598	} else if (delta < LVL_START(5)) {599		idx = calc_index(expires, 4, bucket_expiry);600	} else if (delta < LVL_START(6)) {601		idx = calc_index(expires, 5, bucket_expiry);602	} else if (delta < LVL_START(7)) {603		idx = calc_index(expires, 6, bucket_expiry);604	} else if (LVL_DEPTH > 8 && delta < LVL_START(8)) {605		idx = calc_index(expires, 7, bucket_expiry);

655static void enqueue_timer(struct timer_base *base, struct timer_list *timer,656			  unsigned int idx, unsigned long bucket_expiry)657{658659	hlist_add_head(&timer->entry, base->vectors + idx);660	__set_bit(idx, base->pending_map);661	timer_set_idx(timer, idx);662663	trace_timer_start(timer, bucket_expiry);664665	/*666	 * Check whether this is the new first expiring timer. The667	 * effective expiry time of the timer is required here668	 * (bucket_expiry) instead of timer->expires.669	 */670	if (time_before(bucket_expiry, base->next_expiry)) {671		/*672		 * Set the next expiry time and kick the CPU so it673		 * can reevaluate the wheel:674		 */675		WRITE_ONCE(base->next_expiry, bucket_expiry);676		base->timers_pending = true;

1855{1856	unsigned long clk = base->clk = base->next_expiry;1857	struct hlist_head *vec;1858	int i, levels = 0;1859	unsigned int idx;18601861	for (i = 0; i < LVL_DEPTH; i++) {1862		idx = (clk & LVL_MASK) + i * LVL_SIZE;18631864		if (__test_and_clear_bit(idx, base->pending_map)) {1865			vec = base->vectors + idx;1866			hlist_move_list(vec, heads++);1867			levels++;1868		}1869		/* Is it time to look at the next level? */1870		if (clk & LVL_CLK_MASK)1871			break;1872		/* Shift clock for the next level granularity */1873		clk >>= LVL_CLK_SHIFT;1874	}1875	return levels;1876}