From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756211AbcGGKzV (ORCPT ); Thu, 7 Jul 2016 06:55:21 -0400 Received: from outbound-smtp02.blacknight.com ([81.17.249.8]:44630 "EHLO outbound-smtp02.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751269AbcGGKzU (ORCPT ); Thu, 7 Jul 2016 06:55:20 -0400 Date: Thu, 7 Jul 2016 11:55:16 +0100 From: Mel Gorman To: Minchan Kim Cc: Andrew Morton , Linux-MM , Rik van Riel , Vlastimil Babka , Johannes Weiner , LKML Subject: Re: [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Message-ID: <20160707105516.GT11498@techsingularity.net> References: <1467403299-25786-1-git-send-email-mgorman@techsingularity.net> <1467403299-25786-12-git-send-email-mgorman@techsingularity.net> <20160705061117.GD28164@bbox> <20160705103806.GH11498@techsingularity.net> <20160706012554.GD12570@bbox> <20160706084200.GM11498@techsingularity.net> <20160707062701.GC18072@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20160707062701.GC18072@bbox> 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 Thu, Jul 07, 2016 at 03:27:01PM +0900, Minchan Kim wrote: > > I'm not going to go with it for now because buffer_heads_over_limit is not > > necessarily a problem unless lowmem is factor. We don't want background > > reclaim to go ahead unnecessarily just because buffer_heads_over_limit. > > It could be distinguished by only forcing reclaim to go ahead on systems > > with highmem. > > If you don't think it's a problem, I don't want to insist on it because I don't > have any report/workload right now. Instead, please write some comment in there > for others to understand why kswapd is okay to ignore buffer_heads_over_limit > unlike direct reclaim. Such non-symmetric behavior is really hard to follow > without any description. Ok, I'll add a patch later in the series that addresses the issue. Currently it's called "mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit". -- Mel Gorman SUSE Labs