From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751188AbcGNMyd (ORCPT ); Thu, 14 Jul 2016 08:54:33 -0400 Received: from mx2.suse.de ([195.135.220.15]:59517 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750949AbcGNMyb (ORCPT ); Thu, 14 Jul 2016 08:54:31 -0400 Subject: Re: [PATCH 27/34] mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit To: Mel Gorman , Andrew Morton , Linux-MM References: <1467970510-21195-1-git-send-email-mgorman@techsingularity.net> <1467970510-21195-28-git-send-email-mgorman@techsingularity.net> Cc: Rik van Riel , Johannes Weiner , Minchan Kim , Joonsoo Kim , LKML From: Vlastimil Babka Message-ID: <6a33dd1a-ac19-ced1-a346-e83eea432780@suse.cz> Date: Thu, 14 Jul 2016 14:54:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <1467970510-21195-28-git-send-email-mgorman@techsingularity.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/08/2016 11:35 AM, Mel Gorman wrote: > The buffer_heads_over_limit limit in kswapd is inconsistent with direct > reclaim behaviour. It may force an an attempt to reclaim from all zones and > then not reclaim at all because higher zones were balanced than required > by the original request. > > This patch will causes kswapd to consider reclaiming from all zones if > buffer_heads_over_limit. However, if there are eligible zones for the > allocation request that woke kswapd then no reclaim will occur even if > buffer_heads_over_limit. This avoids kswapd over-reclaiming just because > buffer_heads_over_limit. > > Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka