From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751900AbcFWQE0 (ORCPT ); Thu, 23 Jun 2016 12:04:26 -0400 Received: from outbound-smtp11.blacknight.com ([46.22.139.16]:41353 "EHLO outbound-smtp11.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781AbcFWQDQ (ORCPT ); Thu, 23 Jun 2016 12:03:16 -0400 Date: Thu, 23 Jun 2016 17:03:11 +0100 From: Mel Gorman To: Vlastimil Babka Cc: Michal Hocko , Andrew Morton , Linux-MM , Rik van Riel , Johannes Weiner , LKML Subject: Re: [PATCH 19/27] mm: Move vmscan writes and file write accounting to the node Message-ID: <20160623160311.GA1868@techsingularity.net> References: <1466518566-30034-1-git-send-email-mgorman@techsingularity.net> <1466518566-30034-20-git-send-email-mgorman@techsingularity.net> <20160622144039.GG7527@dhcp22.suse.cz> <20160623135758.GY1868@techsingularity.net> <9a439cbd-6bdc-3c7b-0327-df3b60cdeff8@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <9a439cbd-6bdc-3c7b-0327-df3b60cdeff8@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 Thu, Jun 23, 2016 at 04:06:09PM +0200, Vlastimil Babka wrote: > On 06/23/2016 03:57 PM, Mel Gorman wrote: > >On Wed, Jun 22, 2016 at 04:40:39PM +0200, Michal Hocko wrote: > >>On Tue 21-06-16 15:15:58, Mel Gorman wrote: > >>>As reclaim is now node-based, it follows that page write activity > >>>due to page reclaim should also be accounted for on the node. For > >>>consistency, also account page writes and page dirtying on a per-node > >>>basis. > >>> > >>>After this patch, there are a few remaining zone counters that may > >>>appear strange but are fine. NUMA stats are still per-zone as this is a > >>>user-space interface that tools consume. NR_MLOCK, NR_SLAB_*, NR_PAGETABLE, > >>>NR_KERNEL_STACK and NR_BOUNCE are all allocations that potentially pin > >>>low memory and cannot trivially be reclaimed on demand. This information > >>>is still useful for debugging a page allocation failure warning. > >> > >>As I've said in other patch. I think we will need to provide > >>/proc/nodeinfo to fill the gap. > >> > > > >I added a patch on top that prints the node stats in zoneinfo but only > >once for the first populated zone in a node. Doing this or creating a > >new file are both potentially surprising but extending zoneinfo means > >there is a greater chance that a user will spot the change. > > BTW, there should already be /sys/devices/system/node/nodeX/vmstat providing > the per-node stats, right? > > Changing zoneinfo so that some zones have some stats that others don't seems > to me like it can break some scripts... > I suspect a lot of scripts that read zoneinfo just blindly record it. Similarly, there is no guarantee that a smart script knows to look in the per-node vmstat files either. This is a question of "wait see what breaks". -- Mel Gorman SUSE Labs