From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754792AbcE3MDr (ORCPT ); Mon, 30 May 2016 08:03:47 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:33273 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754755AbcE3MDq (ORCPT ); Mon, 30 May 2016 08:03:46 -0400 Date: Mon, 30 May 2016 14:03:43 +0200 From: Michal Hocko To: linux-mm@kvack.org Cc: Tetsuo Handa , David Rientjes , Oleg Nesterov , Vladimir Davydov , Andrew Morton , LKML Subject: Re: [PATCH 4/6] mm, oom: skip over vforked tasks Message-ID: <20160530120343.GW22928@dhcp22.suse.cz> References: <1464266415-15558-1-git-send-email-mhocko@kernel.org> <1464266415-15558-5-git-send-email-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1464266415-15558-5-git-send-email-mhocko@kernel.org> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org So I've ended up with a replacement for this patch which does the following: --- >>From c40900923c78b51215794cc445d3f5a589b8f785 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Mon, 30 May 2016 13:53:28 +0200 Subject: [PATCH] mm, oom: skip vforked tasks from being selected vforked tasks are not really sitting on any memory. They are sharing the mm with parent until they exec into a new code. Until then it is just pinning the address space. OOM killer will kill the vforked task along with its parent but we still can end up selecting vforked task when the parent wouldn't be selected. E.g. init doing vfork to launch a task or vforked being a child of oom unkillable task with an updated oom_score_adj to be killable. Make sure to not select vforked task as an oom victim by checking vfork_done in oom_badness. Signed-off-by: Michal Hocko --- mm/oom_kill.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 7ba6bdf9ae94..36c821403d0f 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -176,11 +176,13 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, /* * Do not even consider tasks which are explicitly marked oom - * unkillable or have been already oom reaped. + * unkillable or have been already oom reaped or the are in + * the middle of vfork */ adj = (long)p->signal->oom_score_adj; if (adj == OOM_SCORE_ADJ_MIN || - test_bit(MMF_OOM_REAPED, &p->mm->flags)) { + test_bit(MMF_OOM_REAPED, &p->mm->flags) || + p->vfork_done) { task_unlock(p); return 0; } -- 2.8.1 -- Michal Hocko SUSE Labs