From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx113.postini.com [74.125.245.113]) by kanga.kvack.org (Postfix) with SMTP id A963E6B008C for ; Thu, 21 Jun 2012 04:11:31 -0400 (EDT) Message-ID: <4FE2D73C.3060001@kernel.org> Date: Thu, 21 Jun 2012 17:11:40 +0900 From: Minchan Kim MIME-Version: 1.0 Subject: Re: [patch] mm, thp: abort compaction if migration page cannot be charged to memcg References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , Mel Gorman , KAMEZAWA Hiroyuki , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org On 06/21/2012 03:52 PM, David Rientjes wrote: > If page migration cannot charge the new page to the memcg, > migrate_pages() will return -ENOMEM. This isn't considered in memory > compaction however, and the loop continues to iterate over all pageblocks > trying in a futile attempt to continue migrations which are only bound to > fail. Hmm, it might be dumb question. I imagine that pages in next pageblock could be in another memcg so it could be successful. Why should we stop compaction once it fails to migrate pages in current pageblock/memcg? > > This will short circuit and fail memory compaction if migrate_pages() > returns -ENOMEM. COMPACT_PARTIAL is returned in case some migrations > were successful so that the page allocator will retry. > > Signed-off-by: David Rientjes > --- > mm/compaction.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -701,8 +701,11 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) > if (err) { > putback_lru_pages(&cc->migratepages); > cc->nr_migratepages = 0; > + if (err == -ENOMEM) { > + ret = COMPACT_PARTIAL; > + goto out; > + } > } > - > } > > out: -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org