From 31b8384a555d94c78e2ea2284a323cb985441f60 Mon Sep 17 00:00:00 2001
From: Hillf Danton
Date: Tue, 10 Jan 2012 15:07:59 -0800
Subject: mm: compaction: push isolate search base of compact control one pfn
 ahead

After isolated the current pfn will no longer be scanned and isolated if
the next round is necessary, so push the isolate_migratepages search base
of the given compact_control one step ahead.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/compaction.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'mm/compaction.c')

diff --git a/mm/compaction.c b/mm/compaction.c
index 1253d7ac332b..e6670c34eb49 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -365,8 +365,10 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 		nr_isolated++;
 
 		/* Avoid isolating too much */
-		if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
+		if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) {
+			++low_pfn;
 			break;
+		}
 	}
 
 	acct_isolated(zone, cc);
-- 
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