From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755133AbcFQMEF (ORCPT ); Fri, 17 Jun 2016 08:04:05 -0400 Received: from outbound-smtp10.blacknight.com ([46.22.139.15]:55864 "EHLO outbound-smtp10.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752668AbcFQMEE (ORCPT ); Fri, 17 Jun 2016 08:04:04 -0400 Date: Fri, 17 Jun 2016 13:03:59 +0100 From: Mel Gorman To: Vlastimil Babka Cc: Andrew Morton , Linux-MM , Rik van Riel , Johannes Weiner , LKML Subject: Re: [PATCH 21/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Message-ID: <20160617120301.GM1868@techsingularity.net> References: <1465495483-11855-1-git-send-email-mgorman@techsingularity.net> <1465495483-11855-22-git-send-email-mgorman@techsingularity.net> <2ce07fcf-7b7d-a70b-ed7b-60867ad4458f@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <2ce07fcf-7b7d-a70b-ed7b-60867ad4458f@suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 17, 2016 at 12:46:05PM +0200, Vlastimil Babka wrote: > On 06/09/2016 08:04 PM, Mel Gorman wrote: > >kswapd is woken when zones are below the low watermark but the wakeup > >decision is not taking the classzone into account. Now that reclaim is > >node-based, it is only required to wake kswapd once per node and only if > >all zones are unbalanced for the requested classzone. > > > >Note that one node might be checked multiple times but there is no cheap > >way of tracking what nodes have already been visited for zoneslists that > >be ordered by either zone or node. > > Wouldn't it be possible to optimize for node order as you did in direct > reclaim? Do the zone_balanced checks when going through zonelist, and once > node changes in iteration, wake up if no eligible zones visited so far were > balanced. > Yeah, it is. I'll chuck it in. -- Mel Gorman SUSE Labs