From 3a46af9c5a09d8ddecd291e30dc14c22b8cd31e3 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@suse.de>
Date: Mon, 31 Oct 2011 17:09:33 -0700
Subject: [PATCH] --- yaml --- r: 272164 b: refs/heads/master c:
 e0c23279c9f800c403f37511484d9014ac83adec h: refs/heads/master v: v3

---
 [refs]            |  2 +-
 trunk/mm/vmscan.c | 32 +++++++++++++++++++++-----------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/[refs] b/[refs]
index 6283e9939409..38ca5f6d9070 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e0887c19b2daa140f20ca8104bdc5740f39dbb86
+refs/heads/master: e0c23279c9f800c403f37511484d9014ac83adec
diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
index 7e0f05797388..a90c603a8d02 100644
--- a/trunk/mm/vmscan.c
+++ b/trunk/mm/vmscan.c
@@ -2103,14 +2103,19 @@ static void shrink_zone(int priority, struct zone *zone,
  *
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
+ *
+ * This function returns true if a zone is being reclaimed for a costly
+ * high-order allocation and compaction is either ready to begin or deferred.
+ * This indicates to the caller that it should retry the allocation or fail.
  */
-static void shrink_zones(int priority, struct zonelist *zonelist,
+static bool shrink_zones(int priority, struct zonelist *zonelist,
 					struct scan_control *sc)
 {
 	struct zoneref *z;
 	struct zone *zone;
 	unsigned long nr_soft_reclaimed;
 	unsigned long nr_soft_scanned;
+	bool should_abort_reclaim = false;
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
 					gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -2127,19 +2132,20 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
 				continue;	/* Let kswapd poll it */
 			if (COMPACTION_BUILD) {
 				/*
-				 * If we already have plenty of memory
-				 * free for compaction, don't free any
-				 * more.  Even though compaction is
-				 * invoked for any non-zero order,
-				 * only frequent costly order
-				 * reclamation is disruptive enough to
-				 * become a noticable problem, like
-				 * transparent huge page allocations.
+				 * If we already have plenty of memory free for
+				 * compaction in this zone, don't free any more.
+				 * Even though compaction is invoked for any
+				 * non-zero order, only frequent costly order
+				 * reclamation is disruptive enough to become a
+				 * noticable problem, like transparent huge page
+				 * allocations.
 				 */
 				if (sc->order > PAGE_ALLOC_COSTLY_ORDER &&
 					(compaction_suitable(zone, sc->order) ||
-					 compaction_deferred(zone)))
+					 compaction_deferred(zone))) {
+					should_abort_reclaim = true;
 					continue;
+				}
 			}
 			/*
 			 * This steals pages from memory cgroups over softlimit
@@ -2158,6 +2164,8 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
 
 		shrink_zone(priority, zone, sc);
 	}
+
+	return should_abort_reclaim;
 }
 
 static bool zone_reclaimable(struct zone *zone)
@@ -2222,7 +2230,9 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 		sc->nr_scanned = 0;
 		if (!priority)
 			disable_swap_token(sc->mem_cgroup);
-		shrink_zones(priority, zonelist, sc);
+		if (shrink_zones(priority, zonelist, sc))
+			break;
+
 		/*
 		 * Don't shrink slabs when reclaiming memory from
 		 * over limit cgroups