From f0ea6a39be8f07aca147281632e9ef0623c6cffd Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@suse.de>
Date: Wed, 8 Feb 2012 17:13:38 -0800
Subject: [PATCH] --- yaml --- r: 287336 b: refs/heads/master c:
 dc9086004b3d5db75997a645b3fe08d9138b7ad0 h: refs/heads/master v: v3

---
 [refs]                |  2 +-
 trunk/mm/compaction.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index ed28fc7a6ce1..d545a383ac75 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1ecd3c7ea76488c63b4b0a2561fd7eaf96cc8028
+refs/heads/master: dc9086004b3d5db75997a645b3fe08d9138b7ad0
diff --git a/trunk/mm/compaction.c b/trunk/mm/compaction.c
index bd939a574b84..d9ebebe1a2aa 100644
--- a/trunk/mm/compaction.c
+++ b/trunk/mm/compaction.c
@@ -330,8 +330,17 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 			continue;
 		nr_scanned++;
 
-		/* Get the page and skip if free */
+		/*
+		 * Get the page and ensure the page is within the same zone.
+		 * See the comment in isolate_freepages about overlapping
+		 * nodes. It is deliberate that the new zone lock is not taken
+		 * as memory compaction should not move pages between nodes.
+		 */
 		page = pfn_to_page(low_pfn);
+		if (page_zone(page) != zone)
+			continue;
+
+		/* Skip if free */
 		if (PageBuddy(page))
 			continue;