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From: Shaohua Li <shli@kernel.org>
To: linux-mm@kvack.org
Cc: akpm@linux-foundation.org, mgorman@suse.de, aarcange@redhat.com
Subject: [patch 1/2]compaction: check migrated page number
Date: Thu, 6 Sep 2012 18:44:04 +0800	[thread overview]
Message-ID: <20120906104404.GA12718@kernel.org> (raw)


isolate_migratepages_range() might isolate none pages, for example, when
zone->lru_lock is contended and compaction is async. In this case, we should
abort compaction, otherwise, compact_zone will run a useless loop and make
zone->lru_lock is even contended.

Signed-off-by: Shaohua Li <shli@fusionio.com>
---
 mm/compaction.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux/mm/compaction.c
===================================================================
--- linux.orig/mm/compaction.c	2012-08-22 09:51:39.295322268 +0800
+++ linux/mm/compaction.c	2012-09-06 14:46:13.923144263 +0800
@@ -402,6 +402,8 @@ isolate_migratepages_range(struct zone *
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
+	if (!nr_isolated)
+		return 0;
 	return low_pfn;
 }
 

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             reply	other threads:[~2012-09-06 10:44 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-06 10:44 Shaohua Li [this message]
2012-09-06 12:17 ` [patch 1/2]compaction: check migrated page number Mel Gorman
2012-09-06 12:55   ` Shaohua Li
2012-09-06 13:25     ` Mel Gorman
2012-09-07  4:12       ` Shaohua Li
2012-09-07 15:52         ` Andrea Arcangeli
2012-09-10  1:05           ` Shaohua Li

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