diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h
--- a/sys/vm/vm_map.h
+++ b/sys/vm/vm_map.h
@@ -148,6 +148,7 @@
 #define	MAP_ENTRY_STACK_GAP_DN		0x00020000
 #define	MAP_ENTRY_STACK_GAP_UP		0x00040000
 #define	MAP_ENTRY_HEADER		0x00080000
+#define	MAP_ENTRY_ANON_LOC_UPD		0x00400000
 
 #define	MAP_ENTRY_SPLIT_BOUNDARY_MASK	0x00300000
 
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -159,6 +159,12 @@
 #define PROC_VMSPACE_LOCK(p) do { } while (0)
 #define PROC_VMSPACE_UNLOCK(p) do { } while (0)
 
+static int cluster_anon = 1;
+SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW,
+    &cluster_anon, 0,
+    "Cluster anonymous mappings: "
+    "0 = no, 1 = yes if no hint, 2 = always, 3 = keep anon_loc const");
+
 /*
  *	VM_MAP_RANGE_CHECK:	[ internal use only ]
  *
@@ -1700,6 +1706,12 @@
 			return (KERN_INVALID_ARGUMENT);
 		protoeflags |= bidx << MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
 	}
+	if (cluster_anon == 1 || cluster_anon == 2) {
+		if ((object == NULL || (cow & (MAP_INHERIT_SHARE |
+		    MAP_STACK_GROWS_UP | MAP_STACK_GROWS_DOWN |
+		    MAP_ENTRY_GUARD)) == 0) && max != PROT_NONE)
+			protoeflags |= MAP_ENTRY_ANON_LOC_UPD;
+	}
 
 	cred = NULL;
 	if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0)
@@ -1975,26 +1987,27 @@
 static const int aslr_pages_rnd_64[2] = {0x1000, 0x10};
 static const int aslr_pages_rnd_32[2] = {0x100, 0x4};
 
-static int cluster_anon = 1;
-SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW,
-    &cluster_anon, 0,
-    "Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always");
-
 static bool
-clustering_anon_allowed(vm_offset_t addr)
+clustering_anon_allowed(vm_offset_t addr, vm_offset_t anon_loc)
 {
 
 	switch (cluster_anon) {
 	case 0:
 		return (false);
 	case 1:
-		return (addr == 0);
+		return (addr == 0 || addr <= anon_loc);
 	case 2:
 	default:
 		return (true);
 	}
 }
 
+static bool
+clustering_anon_loc_const(void)
+{
+	return (cluster_anon == 3);
+}
+
 static long aslr_restarts;
 SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD,
     &aslr_restarts, 0,
@@ -2111,7 +2124,7 @@
 	} else
 		alignment = 0;
 	en_aslr = (map->flags & MAP_ASLR) != 0;
-	update_anon = cluster = clustering_anon_allowed(*addr) &&
+	update_anon = cluster = clustering_anon_allowed(*addr, map->anon_loc) &&
 	    (map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 &&
 	    find_space != VMFS_NO_SPACE && object == NULL &&
 	    (cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP |
@@ -2226,7 +2239,7 @@
 		rv = vm_map_insert(map, object, offset, *addr, *addr + length,
 		    prot, max, cow);
 	}
-	if (rv == KERN_SUCCESS && update_anon)
+	if (rv == KERN_SUCCESS && update_anon && !clustering_anon_loc_const())
 		map->anon_loc = *addr + length;
 done:
 	vm_map_unlock(map);
@@ -3966,8 +3979,9 @@
 		    entry->object.vm_object != NULL)
 			pmap_map_delete(map->pmap, entry->start, entry->end);
 
-		if (entry->end == map->anon_loc)
-			map->anon_loc = entry->start;
+		if (entry->end == map->anon_loc &&
+		    (entry->eflags & MAP_ENTRY_ANON_LOC_UPD) != 0)
+			map->anon_loc = vm_map_entry_pred(entry)->end;
 
 		/*
 		 * Delete the entry only after removing all pmap