From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752857AbcGTK4G (ORCPT ); Wed, 20 Jul 2016 06:56:06 -0400 Received: from mx2.suse.de ([195.135.220.15]:41113 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752341AbcGTKzz (ORCPT ); Wed, 20 Jul 2016 06:55:55 -0400 Date: Wed, 20 Jul 2016 11:55:49 +0100 From: Mel Gorman To: Minchan Kim Cc: Andrew Morton , Vlastimil Babka , Johannes Weiner , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] mm: add per-zone lru list stat Message-ID: <20160720105549.GU11400@suse.de> References: <1468943433-24805-1-git-send-email-minchan@kernel.org> <20160719164857.GT11400@suse.de> <20160720001624.GA25472@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20160720001624.GA25472@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 Wed, Jul 20, 2016 at 09:16:24AM +0900, Minchan Kim wrote: > On Tue, Jul 19, 2016 at 05:48:57PM +0100, Mel Gorman wrote: > > On Wed, Jul 20, 2016 at 12:50:32AM +0900, Minchan Kim wrote: > > > While I did stress test with hackbench, I got OOM message frequently > > > which didn't ever happen in zone-lru. > > > > > > > This one also showed pgdat going unreclaimable early. Have you tried any > > of the three oom-related patches I sent to Joonsoo to see what impact, > > if any, it had? > > Before the result, I want to say goal of this patch, again. > Without per-zone lru stat, it's really hard to debug OOM problem in > multiple zones system so regardless of solving the problem, we should add > per-zone lru stat for debuggability of OOM which has been never perfect > solution, ever. > That's not in dispute, I simply wanted to know the impact. > The result is not OOM but hackbench stalls forever. Ok, that points to both the premature marking pgdats as unreclaimable and the inactive rotation are both problems. I have a series prepared that may or may not address the problem. I'm trying to reproduce the OOM killer on a 32-bit KVM but so far so luck. If I fail to reproduce it then I cannot tell if the series has an impact and may have to post it and hope you and Joonsoo can test it. -- Mel Gorman SUSE Labs