Message-ID: <4DE4955E.5010503@jp.fujitsu.com>
Date: Tue, 31 May 2011 16:14:38 +0900
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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To: mel@csn.ul.ie
CC: akpm@linux-foundation.org, urykhy@gmail.com, aarcange@redhat.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@kernel.org
Subject: Re: [PATCH] mm: compaction: Abort compaction if too many pages are
 isolated and caller is asynchronous
References: <20110530131300.GQ5044@csn.ul.ie>
In-Reply-To: <20110530131300.GQ5044@csn.ul.ie>
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(2011/05/30 22:13), Mel Gorman wrote:
> Asynchronous compaction is used when promoting to huge pages. This is
> all very nice but if there are a number of processes in compacting
> memory, a large number of pages can be isolated. An "asynchronous"
> process can stall for long periods of time as a result with a user
> reporting that firefox can stall for 10s of seconds. This patch aborts
> asynchronous compaction if too many pages are isolated as it's better to
> fail a hugepage promotion than stall a process.
> 
> If accepted, this should also be considered for 2.6.39-stable. It should
> also be considered for 2.6.38-stable but ideally [11bc82d6: mm:
> compaction: Use async migration for __GFP_NO_KSWAPD and enforce no
> writeback] would be applied to 2.6.38 before consideration.
> 
> Reported-and-Tested-by: Ury Stankevich <urykhy@gmail.com>
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>


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