From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx201.postini.com [74.125.245.201]) by kanga.kvack.org (Postfix) with SMTP id 659366B0070 for ; Thu, 13 Dec 2012 06:12:58 -0500 (EST) Date: Thu, 13 Dec 2012 11:12:54 +0000 From: Mel Gorman Subject: Re: [patch 7/8] mm: vmscan: compaction works against zones, not lruvecs Message-ID: <20121213111254.GB1009@suse.de> References: <1355348620-9382-1-git-send-email-hannes@cmpxchg.org> <1355348620-9382-8-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1355348620-9382-8-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Rik van Riel , Michal Hocko , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Dec 12, 2012 at 04:43:39PM -0500, Johannes Weiner wrote: > The restart logic for when reclaim operates back to back with > compaction is currently applied on the lruvec level. But this does > not make sense, because the container of interest for compaction is a > zone as a whole, not the zone pages that are part of a certain memory > cgroup. > > Negative impact is bounded. For one, the code checks that the lruvec > has enough reclaim candidates, so it does not risk getting stuck on a > condition that can not be fulfilled. And the unfairness of hammering > on one particular memory cgroup to make progress in a zone will be > amortized by the round robin manner in which reclaim goes through the > memory cgroups. Still, this can lead to unnecessary allocation > latencies when the code elects to restart on a hard to reclaim or > small group when there are other, more reclaimable groups in the zone. > > Move this logic to the zone level and restart reclaim for all memory > cgroups in a zone when compaction requires more free pages from it. > > Signed-off-by: Johannes Weiner Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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