---

yaml
---
r: 308837
b: refs/heads/master
c: 4a5b18c
h: refs/heads/master
i:
  308835: 8d31076
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1f1d06c34f7675026326cd9f39ff91e4555cf355
+refs/heads/master: 4a5b18cc1971046d9ca3a29fdcafbe5648629585

trunk/mm/mempolicy.c

@@ -1005,6 +1005,26 @@ int do_migrate_pages(struct mm_struct *mm,
 		int dest = 0;
 
 		for_each_node_mask(s, tmp) {
+
+			/*
+			 * do_migrate_pages() tries to maintain the relative
+			 * node relationship of the pages established between
+			 * threads and memory areas.
+                         *
+			 * However if the number of source nodes is not equal to
+			 * the number of destination nodes we can not preserve
+			 * this node relative relationship.  In that case, skip
+			 * copying memory from a node that is in the destination
+			 * mask.
+			 *
+			 * Example: [2,3,4] -> [3,4,5] moves everything.
+			 *          [0-7] - > [3,4,5] moves only 0,1,2,6,7.
+			 */
+
+			if ((nodes_weight(*from_nodes) != nodes_weight(*to_nodes)) &&
+						(node_isset(s, *to_nodes)))
+				continue;
+
 			d = node_remap(s, *from_nodes, *to_nodes);
 			if (s == d)
 				continue;