From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754736AbaIHRkT (ORCPT ); Mon, 8 Sep 2014 13:40:19 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:45487 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754606AbaIHRkS (ORCPT ); Mon, 8 Sep 2014 13:40:18 -0400 MIME-Version: 1.0 In-Reply-To: <8615268.1yl5ssmHZO@vostro.rjw.lan> References: <1409869842-10807-1-git-send-email-xiyou.wangcong@gmail.com> <20140905224554.GD15723@mtj.dyndns.org> <8615268.1yl5ssmHZO@vostro.rjw.lan> Date: Mon, 8 Sep 2014 10:40:17 -0700 Message-ID: Subject: Re: [Patch v4 1/2] freezer: check OOM kill while being frozen From: Cong Wang To: "Rafael J. Wysocki" Cc: Tejun Heo , LKML , David Rientjes , Michal Hocko , Andrew Morton Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 5, 2014 at 4:32 PM, Rafael J. Wysocki wrote: > On Saturday, September 06, 2014 07:45:54 AM Tejun Heo wrote: >> Hello, >> >> On Fri, Sep 05, 2014 at 11:12:24AM -0700, Cong Wang wrote: >> > > Rafael, can you please help? >> > >> > Rafael is known not responsive at least for this topic. :) >> >> :( > > Well, am I? > > I haven't commented patches in this thread so far, mostly because other > people have. > > How can I help actually? We asked you to comment on either if this patch is safe for PM freeze if we don't have the cgroup_freezing() check, or if it is not safe why (so that I can put it in the comment). > >> > > Shouldn't the primary goal of the comment be explaining why we need >> > > TIF_MEMDIE check there at all anyway? The deadlock possiblity is not >> > > very obvious. >> > >> > The changelog is not long enough?? ;-) I hate to copy+paste changelog >> > into comments, changelog is essentially necessary for people to understand >> > kernel code (at least networking) , so I don't think we have to move it >> > into comments in this case. >> >> It doesn't have to be the same text but the current comment is >> basically content-less. e.g. it can just say "OOM killer may get >> stuck trying to kill a cgroup frozen task" and actualy provide >> information on what condition the conditional tries to address. > > Or something like "We need to check X to prevent Y from happening". > OK, maybe just one or two sentences. Let me know if the following comment is okay for you: /* OOM killer might decide to kill this process after it is frozen, in this case it should thaw and die. */ Thanks.