From c65cc2b0e5d42d6165722322dda4be252193f3d6 Mon Sep 17 00:00:00 2001
From: Hillf Danton <dhillf@gmail.com>
Date: Tue, 10 Jan 2012 15:07:59 -0800
Subject: [PATCH 1/1] 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(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 8c9e638b5e36..764506555bc7 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -387,8 +387,10 @@ 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);
-- 
2.39.2