From 32478136cbe425a4ab392d99dad703d4f4f5cb08 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mel@csn.ul.ie>
Date: Fri, 25 Feb 2011 14:44:20 -0800
Subject: [PATCH] --- yaml --- r: 233695 b: refs/heads/master c:
 2876592f231d436c295b67726313f6f3cfb6e243 h: refs/heads/master i:   233693:
 d5fce455b81fe40a030d68d88df8e0bf4f6979fb   233691:
 65cff7abb0221bee79c512feed7a5671ef9a16c1   233687:
 fb351ac3d88df2e538f988d3e8215d25e0251f4c   233679:
 556773616347c9e1b8885db4955e85051c097ec2   233663:
 36a6cc87cf0d0556707d8dc97b3f454889887eb2 v: v3

---
 [refs]            |  2 +-
 trunk/mm/vmscan.c | 32 ++++++++++++++++++++++----------
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index 2b31bcad66b9..fcdefe016601 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ac3c8304190ed0daaa2fb01ce2a069be5e2a52a7
+refs/heads/master: 2876592f231d436c295b67726313f6f3cfb6e243
diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
index 17497d0cd8b9..6771ea70bfe7 100644
--- a/trunk/mm/vmscan.c
+++ b/trunk/mm/vmscan.c
@@ -1841,16 +1841,28 @@ static inline bool should_continue_reclaim(struct zone *zone,
 	if (!(sc->reclaim_mode & RECLAIM_MODE_COMPACTION))
 		return false;
 
-	/*
-	 * If we failed to reclaim and have scanned the full list, stop.
-	 * NOTE: Checking just nr_reclaimed would exit reclaim/compaction far
-	 *       faster but obviously would be less likely to succeed
-	 *       allocation. If this is desirable, use GFP_REPEAT to decide
-	 *       if both reclaimed and scanned should be checked or just
-	 *       reclaimed
-	 */
-	if (!nr_reclaimed && !nr_scanned)
-		return false;
+	/* Consider stopping depending on scan and reclaim activity */
+	if (sc->gfp_mask & __GFP_REPEAT) {
+		/*
+		 * For __GFP_REPEAT allocations, stop reclaiming if the
+		 * full LRU list has been scanned and we are still failing
+		 * to reclaim pages. This full LRU scan is potentially
+		 * expensive but a __GFP_REPEAT caller really wants to succeed
+		 */
+		if (!nr_reclaimed && !nr_scanned)
+			return false;
+	} else {
+		/*
+		 * For non-__GFP_REPEAT allocations which can presumably
+		 * fail without consequence, stop if we failed to reclaim
+		 * any pages from the last SWAP_CLUSTER_MAX number of
+		 * pages that were scanned. This will return to the
+		 * caller faster at the risk reclaim/compaction and
+		 * the resulting allocation attempt fails
+		 */
+		if (!nr_reclaimed)
+			return false;
+	}
 
 	/*
 	 * If we have not reclaimed enough pages for compaction and the