From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752496AbaDRSpE (ORCPT ); Fri, 18 Apr 2014 14:45:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13474 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457AbaDRSo7 (ORCPT ); Fri, 18 Apr 2014 14:44:59 -0400 Date: Fri, 18 Apr 2014 20:44:41 +0200 From: Oleg Nesterov To: Michal Hocko Cc: Andrew Morton , Peter Chiang , KAMEZAWA Hiroyuki , Balbir Singh , Johannes Weiner , "ccross@android.com" , "lizefan@huawei.com" , "tj@kernel.org" , "pavel@ucw.cz" , "ebiederm@xmission.com" , "guillaume@morinfr.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 0/2] memcg: mm_update_next_owner() should skip kthreads Message-ID: <20140418184441.GA26046@redhat.com> References: <1397617379-26895-1-git-send-email-pchiang@nvidia.com> <80341664FB79C2419999599F48F738410227327881@HKMAIL01.nvidia.com> <80341664FB79C2419999599F48F738410227327888@HKMAIL01.nvidia.com> <20140416135741.GA9407@redhat.com> <80341664FB79C2419999599F48F7384102273279C3@HKMAIL01.nvidia.com> <20140418162359.GA4398@redhat.com> <20140418172631.GA13323@redhat.com> <20140418182444.GB22235@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140418182444.GB22235@dhcp22.suse.cz> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/18, Michal Hocko wrote: > > On Fri 18-04-14 19:26:31, Oleg Nesterov wrote: > > On 04/18, Oleg Nesterov wrote: > > > > > > Hmm. I seem to see a bug in this function, it can be fulled by use_mm, > > > but I am not sure this can explain the problem. I'll send a patch. > > > > Untested, please review. But it really looks "obviously wrong", and note > > that unuse_mm() doesn't do mm_update_next_owner(). (just in case, do not > > confuse it with unuse_mm() in mm/swapfile.c). > > Both patches seem to be correct but I am missinng why they are marked as > memcg: when they are touching generic mm_update_next_owner path. Well, this is because I didn't know which prefix should I use. I looked at git-blame to see who changed this function, picked the random 733eda7ac "memcg: clear mm->owner when last possible owner leaves" commit and copied "memcg" from there. OTOH, mm->owner is used by mm/memcontrol.c, so perhaps the prefix is fine? I do not even understand why do we have CONFIG_MM_OWNER, perhaps it should die? > Anyway, feel free to add > Reviewed-by: Michal Hocko Thanks! Oleg.