Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752850AbdF0Lju (ORCPT ); Tue, 27 Jun 2017 07:39:50 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:32036 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751516AbdF0Ljl (ORCPT ); Tue, 27 Jun 2017 07:39:41 -0400 To: mhocko@kernel.org Cc: linux-mm@kvack.org, rientjes@google.com, oleg@redhat.com, andrea@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] mm, oom: allow oom reaper to race with exit_mmap From: Tetsuo Handa References: <20170626130346.26314-1-mhocko@kernel.org> <201706271952.FEB21375.SFJFHOQLOtVOMF@I-love.SAKURA.ne.jp> <20170627112650.GK28072@dhcp22.suse.cz> In-Reply-To: <20170627112650.GK28072@dhcp22.suse.cz> Message-Id: <201706272039.HGG51520.QOMHFVOFtOSJFL@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.51 PL2] X-Accept-Language: ja,en,zh Date: Tue, 27 Jun 2017 20:39:28 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 410 Lines: 9 Michal Hocko wrote: > > I wonder why you prefer timeout based approach. Your patch will after all > > set MMF_OOM_SKIP if operations between down_write() and up_write() took > > more than one second. > > if we reach down_write then we have unmapped the address space in > exit_mmap and oom reaper cannot do much more. So, by the time down_write() is called, majority of memory is already released, isn't it?