From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 6C2ED6B0069 for ; Mon, 22 Aug 2016 07:20:39 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id o80so59425087wme.1 for ; Mon, 22 Aug 2016 04:20:39 -0700 (PDT) Received: from mail.ud10.udmedia.de (ud10.udmedia.de. [194.117.254.50]) by mx.google.com with ESMTPS id k10si15814321wmh.11.2016.08.22.04.20.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Aug 2016 04:20:38 -0700 (PDT) Date: Mon, 22 Aug 2016 13:20:36 +0200 From: Markus Trippelsdorf Subject: Re: OOM detection regressions since 4.7 Message-ID: <20160822112036.GA305@x4> References: <20160822093249.GA14916@dhcp22.suse.cz> <20160822101614.GA314@x4> <20160822105653.GI13596@dhcp22.suse.cz> <20160822110113.GB314@x4> <20160822111344.GJ13596@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160822111344.GJ13596@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , greg@suse.cz, Linus Torvalds , Arkadiusz Miskiewicz , Ralf-Peter Rohbeck , Jiri Slaby , Olaf Hering , Vlastimil Babka , Joonsoo Kim , linux-mm@kvack.org, LKML On 2016.08.22 at 13:13 +0200, Michal Hocko wrote: > On Mon 22-08-16 13:01:13, Markus Trippelsdorf wrote: > > On 2016.08.22 at 12:56 +0200, Michal Hocko wrote: > > > On Mon 22-08-16 12:16:14, Markus Trippelsdorf wrote: > > > > On 2016.08.22 at 11:32 +0200, Michal Hocko wrote: > > > > > [1] http://lkml.kernel.org/r/20160731051121.GB307@x4 > > > > > > > > For the report [1] above: > > > > > > > > markus@x4 linux % cat .config | grep CONFIG_COMPACTION > > > > # CONFIG_COMPACTION is not set > > > > > > Hmm, without compaction and a heavy fragmentation then I am afraid we > > > cannot really do much. What is the reason to disable compaction in the > > > first place? > > > > I don't recall. Must have been some issue in the past. I will re-enable > > the option. > > Well, without the compaction there is no source of high order pages at > all. You can only reclaim and hope that some of the reclaimed pages will > find its buddy on the list and form the higher order page. This can take > for ever. We used to have the lumpy reclaim and that could help but this > is long gone. > > I do not think we can really sanely optimize for high-order heavy loads > without COMPACTION sanely. At least not without reintroducing lumpy > reclaim or something similar. To be honest I am even not sure which > configurations should disable compaction - except for really highly > controlled !mmu or other one purpose systems. I now recall. It was an issue with CONFIG_TRANSPARENT_HUGEPAGE, so I disabled that option. This then de-selected CONFIG_COMPACTION... -- Markus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org