[PATCH] mm/compaction : fix the wrong return value for isolate_migratepages()

[PATCH] mm/compaction : fix the wrong return value for isolate_migratepages()

[Huang Shijie]

When we do not get any migrate page, we should return ISOLATE_NONE.
If we return ISOLATE_SUCCESS in this case, we may migrate the NORMAL
zone's pages to DMA zone.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 mm/compaction.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 0f12cc9..3db8630 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -376,7 +376,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
-	return ISOLATE_SUCCESS;
+	return (cc->nr_migratepages == 0) ? ISOLATE_NONE : ISOLATE_SUCCESS;
 }
 
 /*
-- 
1.7.3.2


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