From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750869AbdAXMvl (ORCPT ); Tue, 24 Jan 2017 07:51:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:40859 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750792AbdAXMvk (ORCPT ); Tue, 24 Jan 2017 07:51:40 -0500 Date: Tue, 24 Jan 2017 13:51:30 +0100 From: Michal Hocko To: Trevor Cordes Cc: Mel Gorman , linux-kernel@vger.kernel.org, Joonsoo Kim , Minchan Kim , Rik van Riel , Srikar Dronamraju Subject: Re: mm, vmscan: commit makes PAE kernel crash nightly (bisected) Message-ID: <20170124125129.GG6867@dhcp22.suse.cz> References: <20170111165232.0b7abe18@pog.tecnopolis.ca> <20170112093613.GF2264@dhcp22.suse.cz> <20170115002752.4559f668@pog.tecnopolis.ca> <20170116110934.7zopy3ecg2lfadkd@techsingularity.net> <20170117135228.GN19699@dhcp22.suse.cz> <20170117142114.r7abr3x2bbik47sd@techsingularity.net> <20170117145450.GQ19699@dhcp22.suse.cz> <20170119034850.0b7d504c@pog.tecnopolis.ca> <20170119113757.GP30786@dhcp22.suse.cz> <20170120003544.7e6e34d1@pog.tecnopolis.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170120003544.7e6e34d1@pog.tecnopolis.ca> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 20-01-17 00:35:44, Trevor Cordes wrote: > On 2017-01-19 Michal Hocko wrote: > > On Thu 19-01-17 03:48:50, Trevor Cordes wrote: > > > On 2017-01-17 Michal Hocko wrote: > > > > On Tue 17-01-17 14:21:14, Mel Gorman wrote: > > > > > On Tue, Jan 17, 2017 at 02:52:28PM +0100, Michal Hocko > > > > > wrote: > > > > > > On Mon 16-01-17 11:09:34, Mel Gorman wrote: > > > > > > [...] > > > > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > > > > > index 532a2a750952..46aac487b89a 100644 > > > > > > > --- a/mm/vmscan.c > > > > > > > +++ b/mm/vmscan.c > > > > > > > @@ -2684,6 +2684,7 @@ static void shrink_zones(struct > > > > > > > zonelist *zonelist, struct scan_control *sc) continue; > > > > > > > > > > > > > > if (sc->priority != DEF_PRIORITY && > > > > > > > + !buffer_heads_over_limit && > > > > > > > !pgdat_reclaimable(zone->zone_pgdat)) > > > > > > > continue; /* Let > > > > > > > kswapd poll it */ > > > > > > > > > > > > I think we should rather remove pgdat_reclaimable here. This > > > > > > sounds like a wrong layer to decide whether we want to reclaim > > > > > > and how much. > > > > > > > > > > I had considered that but it'd also be important to add the > > > > > other 32-bit patches you have posted to see the impact. Because > > > > > of the ratio of LRU pages to slab pages, it may not have an > > > > > impact but it'd need to be eliminated. > > > > > > > > OK, Trevor you can pull from > > > > git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git tree > > > > fixes/highmem-node-fixes branch. This contains the current mmotm > > > > tree > > > > + the latest highmem fixes. I also do not expect this would help > > > > much in your case but as Mel've said we should rule that out at > > > > least. > > > > > > Hi! The git tree above version oom'd after < 24 hours (3:02am) so > > > it doesn't solve the bug. If you need a oom messages dump let me > > > know. > > > > Yes please. > > The first oom from that night attached. Note, the oom wasn't as dire > with your mhocko/4.9.0+ as it usually is with stock 4.8.x: my oom > detector and reboot script was able to do its thing cleanly before the > system became unusable. Just for reference. This oom was due to bug with the active LRU aging fixed in the Linus tree (b4536f0c829c ("mm, memcg: fix the active list aging for lowmem requests when memcg is enabled") 4.10-rc4) Jan 19 03:02:19 firewallfsi kernel: [85602.858232] Normal free:3436kB min:3532kB low:4412kB high:5292kB active_anon:4kB inactive_anon:8kB active_file:193340kB inactive_file:120kB unevictable :0kB writepending:2516kB present:892920kB managed:816932kB mlocked:0kB slab_reclaimable:522292kB slab_unreclaimable:46724kB kernel_stack:2560kB pagetables:0kB bounce:0kB free_pcp:3468kB loca l_pcp:176kB free_cma:0kB Look at how all the reclaimable memory is on the inactive_file... -- Michal Hocko SUSE Labs