Function zone_alloc_item

freebsd/vm/uma_core.c:4083–4132

 */

static void *
zone_alloc_item(uma_zone_t zone, void *udata, int domain, int flags)
{
	void *item;

	if (zone->uz_max_items > 0 && zone_alloc_limit(zone, 1, flags) == 0) {
		counter_u64_add(zone->uz_fails, 1);
		return (NULL);
	}

	/* Avoid allocs targeting empty domains. */
	if (domain != UMA_ANYDOMAIN && VM_DOMAIN_EMPTY(domain))
		domain = UMA_ANYDOMAIN;

	if (zone->uz_import(zone->uz_arg, &item, 1, domain, flags) != 1)
		goto fail_cnt;

	/*
	 * We have to call both the zone's init (not the keg's init)
	 * and the zone's ctor.  This is because the item is going from
	 * a keg slab directly to the user, and the user is expecting it
	 * to be both zone-init'd as well as zone-ctor'd.
	 */
	if (zone->uz_init != NULL) {
		if (zone->uz_init(item, zone->uz_size, flags) != 0) {
			zone_free_item(zone, item, udata, SKIP_FINI | SKIP_CNT);
			goto fail_cnt;
		}
	}
	item = item_ctor(zone, zone->uz_flags, zone->uz_size, udata, flags,
	    item);
	if (item == NULL)
		goto fail;

	counter_u64_add(zone->uz_allocs, 1);
	CTR3(KTR_UMA, "zone_alloc_item item %p from %s(%p)", item,
	    zone->uz_name, zone);

	return (item);

fail_cnt:
	counter_u64_add(zone->uz_fails, 1);
fail:
	if (zone->uz_max_items > 0)
		zone_free_limit(zone, 1);
	CTR2(KTR_UMA, "zone_alloc_item failed from %s(%p)",
	    zone->uz_name, zone);

	return (NULL);
}

/* See uma.h */
void