From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84923C433DF for ; Thu, 20 Aug 2020 14:05:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6998A20724 for ; Thu, 20 Aug 2020 14:05:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726741AbgHTOFi (ORCPT ); Thu, 20 Aug 2020 10:05:38 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:47579 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728023AbgHTOBZ (ORCPT ); Thu, 20 Aug 2020 10:01:25 -0400 Received: from ip5f5af70b.dynamic.kabel-deutschland.de ([95.90.247.11] helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1k8l7f-0000JS-Nv; Thu, 20 Aug 2020 14:00:55 +0000 Date: Thu, 20 Aug 2020 16:00:54 +0200 From: Christian Brauner To: Tetsuo Handa , "Eric W. Biederman" , Michal Hocko Cc: Suren Baghdasaryan , timmurray@google.com, "Eric W. Biederman" , mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, esyr@redhat.com, christian@kellner.me, areber@redhat.com, shakeelb@google.com, cyphar@cyphar.com, oleg@redhat.com, adobriyan@gmail.com, akpm@linux-foundation.org, gladkov.alexey@gmail.com, walken@google.com, daniel.m.jordan@oracle.com, avagin@gmail.com, bernd.edlinger@hotmail.de, john.johansen@canonical.com, laoar.shao@gmail.com, minchan@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/1] mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary Message-ID: <20200820140054.fdkbotd4tgfrqpe6@wittgenstein> References: <20200820002053.1424000-1-surenb@google.com> <87zh6pxzq6.fsf@x220.int.ebiederm.org> <20200820124241.GJ5033@dhcp22.suse.cz> <87lfi9xz7y.fsf@x220.int.ebiederm.org> <87d03lxysr.fsf@x220.int.ebiederm.org> <20200820132631.GK5033@dhcp22.suse.cz> <20200820133454.ch24kewh42ax4ebl@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 20, 2020 at 10:48:43PM +0900, Tetsuo Handa wrote: > On 2020/08/20 22:34, Christian Brauner wrote: > > On Thu, Aug 20, 2020 at 03:26:31PM +0200, Michal Hocko wrote: > >> If you can handle vfork by other means then I am all for it. There were > >> no patches in that regard proposed yet. Maybe it will turn out simpler > >> then the heavy lifting we have to do in the oom specific code. > > > > Eric's not wrong. I fiddled with this too this morning but since > > oom_score_adj is fiddled with in a bunch of places this seemed way more > > code churn then what's proposed here. > > I prefer simply reverting commit 44a70adec910d692 ("mm, oom_adj: make sure > processes sharing mm have same view of oom_score_adj"). > > https://lore.kernel.org/patchwork/patch/1037208/ I guess this is a can of worms but just or the sake of getting more background: the question seems to be whether the oom adj score is a property of the task/thread-group or a property of the mm. I always thought the oom score is a property of the task/thread-group and not the mm which is also why it lives in struct signal_struct and not in struct mm_struct. But 44a70adec910 ("mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj") reads like it is supposed to be a property of the mm or at least the change makes it so. Christian