Index: sys/vm/vm_map.c
===================================================================
--- sys/vm/vm_map.c
+++ sys/vm/vm_map.c
@@ -917,36 +917,52 @@
 	entry->max_free = MAX(max_left, max_right);
 }
 
-#define SPLAY_LEFT_STEP(root, y, rlist, test) do {	\
-	y = root->left;					\
-	if (y != NULL && (test)) {			\
-		/* Rotate right and make y root. */	\
-		root->left = y->right;			\
-		y->right = root;			\
-		vm_map_entry_set_max_free(root);	\
-		root = y;				\
-		y = root->left;				\
-	}						\
-	/* Put root on rlist. */			\
-	root->left = rlist;				\
-	rlist = root;					\
-	root = y;					\
+#define SPLAY_LEFT_STEP(root, y, rlist, test) do {			\
+	y = root->left;							\
+	if (y != NULL && (test)) {					\
+		/* Rotate right and make y root. */			\
+		root->left = y->right;					\
+		y->right = root;					\
+		if (root->max_free == y->max_free)			\
+			vm_map_entry_set_max_free(root);		\
+		root = y;						\
+		y = root->left;						\
+	}								\
+	/* Put root on rlist. */					\
+	root->left = rlist;						\
+	rlist = root;							\
+	root = y;							\
+	/* Make rlist->max_free match max_free for its right child. */	\
+	if (rlist->max_free == ((root != NULL) ?			\
+	    root->max_free : rlist->start - rlist->prev->end)) {	\
+		y = rlist->right;					\
+		rlist->max_free = (y != NULL) ?				\
+		    y->max_free : rlist->next->start - rlist->end;	\
+	}								\
 } while (0)
 
-#define SPLAY_RIGHT_STEP(root, y, llist, test) do {	\
-	y = root->right;				\
-	if (y != NULL && (test)) {			\
-		/* Rotate left and make y root. */	\
-		root->right = y->left;			\
-		y->left = root;				\
-		vm_map_entry_set_max_free(root);	\
-		root = y;				\
-		y = root->right;			\
-	}						\
-	/* Put root on llist. */			\
-	root->right = llist;				\
-	llist = root;					\
-	root = y;					\
+#define SPLAY_RIGHT_STEP(root, y, llist, test) do {			\
+	y = root->right;						\
+	if (y != NULL && (test)) {					\
+		/* Rotate left and make y root. */			\
+		root->right = y->left;					\
+		y->left = root;						\
+		if (root->max_free == y->max_free)			\
+			vm_map_entry_set_max_free(root);		\
+		root = y;						\
+		y = root->right;					\
+	}								\
+	/* Put root on llist. */					\
+	root->right = llist;						\
+	llist = root;							\
+	root = y;							\
+	/* Make llist->max_free match max_free for its left child. */	\
+	if (llist->max_free == ((root != NULL) ?			\
+	    root->max_free : llist->next->start - llist->end)) {	\
+		y = llist->left;					\
+		llist->max_free = (y != NULL) ?				\
+		    y->max_free : llist->start - llist->prev->end;	\
+	}								\
 } while (0)
 
 /*
@@ -1015,18 +1031,31 @@
     vm_map_entry_t ltree, vm_map_entry_t rtree)
 {
 	vm_map_entry_t y;
+	vm_size_t max_free;
 
+	if (llist != NULL)
+		max_free = (ltree != NULL) ? ltree->max_free :
+		    llist->next->start - llist->end;
 	while (llist != NULL) {
 		y = llist->right;
 		llist->right = ltree;
-		vm_map_entry_set_max_free(llist);
+		if (llist->max_free < max_free)
+			llist->max_free = max_free;
+		else
+			max_free = llist->max_free;
 		ltree = llist;
 		llist = y;
 	}
+	if (rlist != NULL)
+		max_free = (rtree != NULL) ? rtree->max_free :
+		    rlist->start - rlist->prev->end;
 	while (rlist != NULL) {
 		y = rlist->left;
 		rlist->left = rtree;
-		vm_map_entry_set_max_free(rlist);
+		if (rlist->max_free < max_free)
+			rlist->max_free = max_free;
+		else
+			max_free = rlist->max_free;
 		rtree = rlist;
 		rlist = y;
 	}
@@ -1132,10 +1161,6 @@
 	vm_map_entry_t llist, rlist, root, y;
 
 	VM_MAP_ASSERT_LOCKED(map);
-	llist = entry->prev;
-	rlist = entry->next;
-	llist->next = rlist;
-	rlist->prev = llist;
 	root = map->root;
 	root = vm_map_splay_split(entry->start, 0, root, &llist, &rlist);
 	KASSERT(root != NULL,
@@ -1174,6 +1199,9 @@
 			root = NULL;
 		break;
 	}
+	y = entry->next;
+	y->prev = entry->prev;
+	y->prev->next = y;
 	if (root != NULL)
 		root = vm_map_splay_merge(root, llist, rlist,
 		    root->left, root->right);