Index: sys/vm/vm_map.c
===================================================================
--- sys/vm/vm_map.c
+++ sys/vm/vm_map.c
@@ -1033,27 +1033,39 @@
 	map->root = entry;
 }
 
+enum unlink_merge_type {UNLINK_MERGE_PREV, UNLINK_MERGE_NONE, UNLINK_MERGE_NEXT};
+
 static void
 vm_map_entry_unlink(vm_map_t map,
-		    vm_map_entry_t entry)
+		    vm_map_entry_t entry,
+		    unlink_merge_type op)
 {
 	vm_map_entry_t next, prev, root;
 
 	VM_MAP_ASSERT_LOCKED(map);
+	prev = entry->prev;
+	next = entry->next;
 	if (entry != map->root)
 		vm_map_entry_splay(entry->start, map->root);
-	if (entry->left == NULL)
+	if (prev == &map->header)
 		root = entry->right;
 	else {
-		root = vm_map_entry_splay(entry->start, entry->left);
+		root = vm_map_entry_splay(prev->start, entry->left);
 		root->right = entry->right;
-		root->adj_free = entry->next->start - root->end;
+		switch(op) {
+		case UNLINK_MERGE_PREV:
+			prev->end = entry->end;
+			break;
+		case UNLINK_MERGE_NONE:
+			break;
+		case UNLINK_MERGE_NEXT:
+			next->start = entry->start;
+			break;
+		}
+		prev->adj_free = next->start - prev->end;
 		vm_map_entry_set_max_free(root);
 	}
 	map->root = root;
-
-	prev = entry->prev;
-	next = entry->next;
 	next->prev = prev;
 	prev->next = next;
 	map->nentries--;
@@ -1710,20 +1722,15 @@
 	prev = entry->prev;
 	if (prev != &map->header &&
 	    vm_map_mergeable_neighbors(prev, entry)) {
-		vm_map_entry_unlink(map, prev);
-		entry->start = prev->start;
+		vm_map_entry_unlink(map, prev, UNLINK_MERGE_NEXT);
 		entry->offset = prev->offset;
-		if (entry->prev != &map->header)
-			vm_map_entry_resize_free(map, entry->prev);
 		vm_map_merged_neighbor_dispose(map, prev);
 	}
 
 	next = entry->next;
 	if (next != &map->header &&
 	    vm_map_mergeable_neighbors(entry, next)) {
-		vm_map_entry_unlink(map, next);
-		entry->end = next->end;
-		vm_map_entry_resize_free(map, entry);
+		vm_map_entry_unlink(map, next, UNLINK_MERGE_PREV);
 		vm_map_merged_neighbor_dispose(map, next);
 	}
 }
@@ -3007,7 +3014,7 @@
 	vm_pindex_t offidxstart, offidxend, count, size1;
 	vm_size_t size;
 
-	vm_map_entry_unlink(map, entry);
+	vm_map_entry_unlink(map, entry, UNLINK_MERGE_NONE);
 	object = entry->object.vm_object;
 
 	if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {