Function zone_free_limit

freebsd/vm/uma_core.c:3975–3996

* Free a number of items back to the limit. */

 * Free a number of items back to the limit.
 */
static void
zone_free_limit(uma_zone_t zone, int count)
{
	uint64_t old;

	MPASS(count > 0);

	/*
	 * In the common case we either have no sleepers or
	 * are still over the limit and can just return.
	 */
	old = atomic_fetchadd_64(&zone->uz_items, -count);
	if (__predict_true(UZ_ITEMS_SLEEPERS(old) == 0 ||
	   UZ_ITEMS_COUNT(old) - count >= zone->uz_max_items))
		return;

	/*
	 * Moderate the rate of wakeups.  Sleepers will continue
	 * to generate wakeups if necessary.
	 */
	wakeup_one(&zone->uz_max_items);
}

static uma_bucket_t
zone_alloc_bucket(uma_zone_t zone, void *udata, int domain, int flags)