Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -685,8 +685,13 @@
 		if (STAILQ_NEXT(bucket, ub_link) != NULL)
 			zdom->uzd_seq = STAILQ_NEXT(bucket, ub_link)->ub_seq;
 	}
-	MPASS(zdom->uzd_nitems >= bucket->ub_cnt);
 	STAILQ_REMOVE_HEAD(&zdom->uzd_buckets, ub_link);
+
+	KASSERT(zdom->uzd_nitems >= bucket->ub_cnt,
+	    ("%s: item count underflow (%ld, %d)",
+	    __func__, zdom->uzd_nitems, bucket->ub_cnt));
+	KASSERT(bucket->ub_cnt > 0,
+	    ("%s: empty bucket in bucket cache", __func__));
 	zdom->uzd_nitems -= bucket->ub_cnt;
 
 	/*
@@ -914,11 +919,8 @@
 	 * Check the zone's cache of buckets.
 	 */
 	zdom = zone_domain_lock(zone, domain);
-	if ((bucket = zone_fetch_bucket(zone, zdom, false)) != NULL) {
-		KASSERT(bucket->ub_cnt != 0,
-		    ("cache_fetch_bucket: Returning an empty bucket."));
+	if ((bucket = zone_fetch_bucket(zone, zdom, false)) != NULL)
 		return (bucket);
-	}
 	ZDOM_UNLOCK(zdom);
 
 	return (NULL);
@@ -3495,6 +3497,11 @@
 void *
 uma_zalloc_domain(uma_zone_t zone, void *udata, int domain, int flags)
 {
+#ifdef NUMA
+	uma_bucket_t bucket;
+	uma_zone_domain_t zdom;
+	void *item;
+#endif
 
 	/* Enable entropy collection for RANDOM_ENABLE_UMA kernel option */
 	random_harvest_fast_uma(&zone, sizeof(zone), RANDOM_UMA);
@@ -3509,8 +3516,45 @@
 	}
 	KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
 	    ("uma_zalloc_domain: called with spinlock or critical section held"));
+	KASSERT((zone->uz_flags & UMA_ZONE_SMR) == 0,
+	    ("uma_zalloc_domain: called with SMR zone."));
+#ifdef NUMA
+	KASSERT((zone->uz_flags & UMA_ZONE_FIRSTTOUCH) != 0,
+	    ("uma_zalloc_domain: called with non-FIRSTTOUCH zone."));
 
+	if (vm_ndomains == 1)
+		return (uma_zalloc_arg(zone, udata, flags));
+
+	/*
+	 * Try to allocate from the bucket cache before falling back to the keg.
+	 * We could try harder and attempt to allocate from per-CPU caches or
+	 * the per-domain cross-domain buckets, but the complexity is probably
+	 * not worth it.  It is more important that frees of previous
+	 * cross-domain allocations do not blow up the cache.
+	 */
+	zdom = zone_domain_lock(zone, domain);
+	if ((bucket = zone_fetch_bucket(zone, zdom, false)) != NULL) {
+		item = bucket->ub_bucket[bucket->ub_cnt - 1];
+#ifdef INVARIANTS
+		bucket->ub_bucket[bucket->ub_cnt - 1] = NULL;
+#endif
+		bucket->ub_cnt--;
+		zone_put_bucket(zone, domain, bucket, udata, true);
+		item = item_ctor(zone, zone->uz_flags, zone->uz_size, udata,
+		    flags, item);
+		if (item != NULL) {
+			KASSERT(item_domain(item) == domain,
+			    ("%s: bucket cache item %p from wrong domain",
+			    __func__, item));
+			counter_u64_add(zone->uz_allocs, 1);
+		}
+		return (item);
+	}
+	ZDOM_UNLOCK(zdom);
 	return (zone_alloc_item(zone, udata, domain, flags));
+#else
+	return (uma_zalloc_arg(zone, udata, flags));
+#endif
 }
 
 /*