From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 1260B6B025F for ; Wed, 4 Oct 2017 16:31:45 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id l10so387559wre.4 for ; Wed, 04 Oct 2017 13:31:45 -0700 (PDT) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id s6si3528636eda.14.2017.10.04.13.31.43 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 04 Oct 2017 13:31:43 -0700 (PDT) Date: Wed, 4 Oct 2017 16:31:38 -0400 From: Johannes Weiner Subject: Re: [v10 3/6] mm, oom: cgroup-aware OOM killer Message-ID: <20171004203138.GA2632@cmpxchg.org> References: <20171004154638.710-1-guro@fb.com> <20171004154638.710-4-guro@fb.com> <20171004192720.GC1501@cmpxchg.org> <20171004195110.GA18900@castle> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Roman Gushchin , linux-mm@kvack.org, Michal Hocko , Vladimir Davydov , Tetsuo Handa , Andrew Morton , Tejun Heo , kernel-team@fb.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org On Wed, Oct 04, 2017 at 01:17:14PM -0700, David Rientjes wrote: > On Wed, 4 Oct 2017, Roman Gushchin wrote: > > > > > @@ -828,6 +828,12 @@ static void __oom_kill_process(struct task_struct *victim) > > > > struct mm_struct *mm; > > > > bool can_oom_reap = true; > > > > > > > > + if (is_global_init(victim) || (victim->flags & PF_KTHREAD) || > > > > + victim->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { > > > > + put_task_struct(victim); > > > > + return; > > > > + } > > > > + > > > > p = find_lock_task_mm(victim); > > > > if (!p) { > > > > put_task_struct(victim); > > > > > > Is this necessary? The callers of this function use oom_badness() to > > > find a victim, and that filters init, kthread, OOM_SCORE_ADJ_MIN. > > > > It is. __oom_kill_process() is used to kill all processes belonging > > to the selected memory cgroup, so we should perform these checks > > to avoid killing unkillable processes. > > > > That's only true after the next patch in the series which uses the > oom_kill_memcg_member() callback to kill processes for oom_group, correct? > Would it be possible to move this check to that patch so it's more > obvious? Yup, I realized it when reviewing the next patch. Moving this hunk to the next patch would probably make sense. Although, us reviewers have been made aware of this now, so I don't feel strongly about it. Won't make much of a difference once the patches are merged. -- 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