From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751654AbcGUHG6 (ORCPT ); Thu, 21 Jul 2016 03:06:58 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:46425 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751531AbcGUHGz (ORCPT ); Thu, 21 Jul 2016 03:06:55 -0400 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 165.244.98.150 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.223.161 X-Original-MAILFROM: minchan@kernel.org Date: Thu, 21 Jul 2016 16:07:14 +0900 From: Minchan Kim To: Mel Gorman CC: Andrew Morton , Johannes Weiner , Michal Hocko , Vlastimil Babka , Linux-MM , LKML Subject: Re: [PATCH 0/5] Candidate fixes for premature OOM kills with node-lru v1 Message-ID: <20160721070714.GC31865@bbox> References: <1469028111-1622-1-git-send-email-mgorman@techsingularity.net> MIME-Version: 1.0 In-Reply-To: <1469028111-1622-1-git-send-email-mgorman@techsingularity.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-MIMETrack: Itemize by SMTP Server on LGEKRMHUB08/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2016/07/21 16:06:53, Serialize by Router on LGEKRMHUB08/LGE/LG Group(Release 8.5.3FP6|November 21, 2013) at 2016/07/21 16:06:53, Serialize complete at 2016/07/21 16:06:53 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mel, On Wed, Jul 20, 2016 at 04:21:46PM +0100, Mel Gorman wrote: > Both Joonsoo Kim and Minchan Kim have reported premature OOM kills on > a 32-bit platform. The common element is a zone-constrained high-order > allocation failing. Two factors appear to be at fault -- pgdat being Strictly speaking, my case is order-0 allocation failing, not high-order. ;) > considered unreclaimable prematurely and insufficient rotation of the > active list. > > Unfortunately to date I have been unable to reproduce this with a variety > of stress workloads on a 2G 32-bit KVM instance. It's not clear why as > the steps are similar to what was described. It means I've been unable to > determine if this series addresses the problem or not. I'm hoping they can > test and report back before these are merged to mmotm. What I have checked > is that a basic parallel DD workload completed successfully on the same > machine I used for the node-lru performance tests. I'll leave the other > tests running just in case anything interesting falls out. > > The series is in three basic parts; > > Patch 1 does not account for skipped pages as scanned. This avoids the pgdat > being prematurely marked unreclaimable > > Patches 2-4 add per-zone stats back in. The actual stats patch is different > to Minchan's as the original patch did not account for unevictable > LRU which would corrupt counters. The second two patches remove > approximations based on pgdat statistics. It's effectively a > revert of "mm, vmstat: remove zone and node double accounting by > approximating retries" but different LRU stats are used. This > is better than a full revert or a reworking of the series as > it preserves history of why the zone stats are necessary. > > If this work out, we may have to leave the double accounting in > place for now until an alternative cheap solution presents itself. > > Patch 5 rotates inactive/active lists for lowmem allocations. This is also > quite different to Minchan's patch as the original patch did not > account for memcg and would rotate if *any* eligible zone needed > rotation which may rotate excessively. The new patch considers > the ratio for all eligible zones which is more in line with > node-lru in general. > Now I tested and confirmed it works for me at the OOM point of view. IOW, I cannot see OOM kill any more. But note that I tested it without [1/5] which has a problem I mentioned in that thread. If you want to merge [1/5], please resend updated version but I doubt we need it at this moment.