Index: head/sys/vm/uma.h
===================================================================
--- head/sys/vm/uma.h
+++ head/sys/vm/uma.h
@@ -265,8 +265,8 @@
 					 * information in the vm_page.
 					 */
 #define	UMA_ZONE_SECONDARY	0x0200	/* Zone is a Secondary Zone */
-/*				0x0400	   Unused */
-#define	UMA_ZONE_MAXBUCKET	0x0800	/* Use largest buckets */
+#define	UMA_ZONE_NOBUCKET	0x0400	/* Do not use buckets. */
+#define	UMA_ZONE_MAXBUCKET	0x0800	/* Use largest buckets. */
 #define	UMA_ZONE_CACHESPREAD	0x1000	/*
 					 * Spread memory start locations across
 					 * all possible cache lines.  May
Index: head/sys/vm/uma_core.c
===================================================================
--- head/sys/vm/uma_core.c
+++ head/sys/vm/uma_core.c
@@ -1681,10 +1681,15 @@
 	}
 
 out:
-	if ((arg->flags & UMA_ZONE_MAXBUCKET) == 0)
-		zone->uz_count = bucket_select(zone->uz_size);
-	else
+	KASSERT((arg->flags & (UMA_ZONE_MAXBUCKET | UMA_ZONE_NOBUCKET)) !=
+	    (UMA_ZONE_MAXBUCKET | UMA_ZONE_NOBUCKET),
+	    ("Invalid zone flag combination"));
+	if ((arg->flags & UMA_ZONE_MAXBUCKET) != 0)
 		zone->uz_count = BUCKET_MAX;
+	else if ((arg->flags & UMA_ZONE_NOBUCKET) != 0)
+		zone->uz_count = 0;
+	else
+		zone->uz_count = bucket_select(zone->uz_size);
 	zone->uz_count_min = zone->uz_count;
 
 	return (0);