Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -361,6 +361,12 @@
 SYSCTL_INT(_vm, OID_AUTO, zone_warnings, CTLFLAG_RWTUN, &zone_warnings, 0,
     "Warn when UMA zones becomes full");
 
+static int multipage_slabs = 1;
+TUNABLE_INT("vm.multipage_slabs", &multipage_slabs);
+SYSCTL_INT(_vm, OID_AUTO, multipage_slabs,
+    CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &multipage_slabs, 0,
+    "UMA may choose larger slab sizes for better efficiency");
+
 /*
  * Select the slab zone for an offpage slab with the given maximum item count.
  */
@@ -1989,7 +1995,7 @@
 				break;
 		}
 
-		if (kl.eff >= UMA_MIN_EFF ||
+		if (kl.eff >= UMA_MIN_EFF || !multipage_slabs ||
 		    slabsize >= SLAB_MAX_SETSIZE * rsize ||
 		    (keg->uk_flags & (UMA_ZONE_PCPU | UMA_ZONE_CONTIG)) != 0)
 			break;