From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750950AbeDDJqp (ORCPT ); Wed, 4 Apr 2018 05:46:45 -0400 Received: from mail.netline.ch ([148.251.143.178]:40011 "EHLO netline-mail3.netline.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736AbeDDJqo (ORCPT ); Wed, 4 Apr 2018 05:46:44 -0400 Subject: Re: [RFC] Per file OOM badness To: Lucas Stach , Michal Hocko Cc: linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christian.Koenig@amd.com, linux-mm@kvack.org, dri-devel@lists.freedesktop.org, Roman Gushchin References: <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> <20180124110141.GA28465@dhcp22.suse.cz> <36b49523-792d-45f9-8617-32b6d9d77418@daenzer.net> <20180124115059.GC28465@dhcp22.suse.cz> <60e18da8-4d6e-dec9-7aef-ff003605d513@daenzer.net> <20180130102855.GY21609@dhcp22.suse.cz> <1522074988.1196.1.camel@pengutronix.de> <3778a205-8b30-d147-b1f6-0a93d1de8beb@daenzer.net> <1522834611.3779.3.camel@pengutronix.de> From: =?UTF-8?Q?Michel_D=c3=a4nzer?= Message-ID: Date: Wed, 4 Apr 2018 11:46:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1522834611.3779.3.camel@pengutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-04-04 11:36 AM, Lucas Stach wrote: > Am Mittwoch, den 04.04.2018, 11:09 +0200 schrieb Michel Dänzer: >> On 2018-03-26 04:36 PM, Lucas Stach wrote: >>> Am Dienstag, den 30.01.2018, 11:28 +0100 schrieb Michal Hocko: >>>> On Tue 30-01-18 10:29:10, Michel Dänzer wrote: >>>>> On 2018-01-24 12:50 PM, Michal Hocko wrote: >>>>>> On Wed 24-01-18 12:23:10, Michel Dänzer wrote: >>>>>>> On 2018-01-24 12:01 PM, Michal Hocko wrote: >>>>>>>> On Wed 24-01-18 11:27:15, Michel Dänzer wrote: >>>>>> >>>>>> [...] >>>>>>>>> 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? >>>>>>> >>>>>>> I'm not sure what you're asking. Userspace mostly uses a GEM >>>>>>> handle to >>>>>>> refer to a BO. There can also be userspace CPU mappings of the >>>>>>> BO's >>>>>>> memory, but userspace doesn't need CPU mappings for all BOs and >>>>>>> only >>>>>>> creates them as needed. >>>>>> >>>>>> OK, I guess you have to bear with me some more. This whole stack >>>>>> is a >>>>>> complete uknonwn. I am mostly after finding a boundary where you >>>>>> can >>>>>> charge the allocated memory to the process so that the oom killer >>>>>> can >>>>>> consider it. Is there anything like that? Except for the proposed >>>>>> file >>>>>> handle hack? >>>>> >>>>> How about the other way around: what APIs can we use to charge / >>>>> "uncharge" memory to a process? If we have those, we can experiment >>>>> with >>>>> different places to call them. >>>> >>>> add_mm_counter() and I would add a new counter e.g. MM_KERNEL_PAGES. >>> >>> So is anyone still working on this? This is hurting us bad enough that >>> I don't want to keep this topic rotting for another year. >>> >>> If no one is currently working on this I would volunteer to give the >>> simple "just account private, non-shared buffers in process RSS" a >>> spin. >> >> Sounds good. FWIW, I think shared buffers can also be easily handled by >> accounting them in each process which has a reference. But that's more >> of a detail, shouldn't make a big difference overall either way. > > Yes, both options to wither never account shared buffers or to always > account them into every process having a reference should be pretty > easy. Where it gets hard is when trying to account the buffer only in > the last process holding a reference or something like this. FWIW, I don't think that would make sense anyway. A shared buffer is actually used by all processes which have a reference to it, so it should be accounted the same in all of them. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer