From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933214AbeAXLBv (ORCPT ); Wed, 24 Jan 2018 06:01:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:49393 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933161AbeAXLBp (ORCPT ); Wed, 24 Jan 2018 06:01:45 -0500 Date: Wed, 24 Jan 2018 12:01:41 +0100 From: Michal Hocko To: Michel =?iso-8859-1?Q?D=E4nzer?= Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Christian.Koenig@amd.com, linux-mm@kvack.org, amd-gfx@lists.freedesktop.org, Roman Gushchin Subject: Re: [RFC] Per file OOM badness Message-ID: <20180124110141.GA28465@dhcp22.suse.cz> References: <1516294072-17841-1-git-send-email-andrey.grodzovsky@amd.com> <20180118170006.GG6584@dhcp22.suse.cz> <20180123152659.GA21817@castle.DHCP.thefacebook.com> <20180123153631.GR1526@dhcp22.suse.cz> <20180124092847.GI1526@dhcp22.suse.cz> <583f328e-ff46-c6a4-8548-064259995766@daenzer.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <583f328e-ff46-c6a4-8548-064259995766@daenzer.net> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 24-01-18 11:27:15, Michel Dänzer wrote: > On 2018-01-24 10:28 AM, Michal Hocko wrote: [...] > > So how exactly then helps to kill one of those processes? The memory > > stays pinned behind or do I still misunderstand? > > Fundamentally, the memory is only released once all references to the > BOs are dropped. That's true no matter how the memory is accounted for > between the processes referencing the BO. > > > In practice, this should be fine: > > 1. The amount of memory used for shared BOs is normally small compared > to the amount of memory used for non-shared BOs (and other things). So > regardless of how shared BOs are accounted for, the OOM killer should > first target the process which is responsible for more memory overall. OK. So this is essentially the same as with the normal shared memory which is a part of the RSS in general. > 2. If the OOM killer kills a process which is sharing BOs with another > process, this should result in the other process dropping its references > to the BOs as well, at which point the memory is released. OK. How exactly are those BOs mapped to the userspace? -- Michal Hocko SUSE Labs