From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755323Ab1JKTMK (ORCPT ); Tue, 11 Oct 2011 15:12:10 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:33977 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754948Ab1JKTMI (ORCPT ); Tue, 11 Oct 2011 15:12:08 -0400 From: "Rafael J. Wysocki" To: Jeff Layton Subject: Re: [PATCH 1/4] freezer: make fake_signal_wake_up wake TASK_KILLABLE tasks too Date: Tue, 11 Oct 2011 21:14:28 +0200 User-Agent: KMail/1.13.6 (Linux/3.1.0-rc9+; KDE/4.6.0; x86_64; ; ) Cc: Pavel Machek , trond.myklebust@netapp.com, smfrench@gmail.com, linux-pm@lists.linux-foundation.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, john@calva.com, linux-kernel@vger.kernel.org References: <1317210761-11518-1-git-send-email-jlayton@redhat.com> <20111011061847.GB1377@ucw.cz> <20111011061000.3a3a03fe@tlielax.poochiereds.net> In-Reply-To: <20111011061000.3a3a03fe@tlielax.poochiereds.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201110112114.28478.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, October 11, 2011, Jeff Layton wrote: > On Tue, 11 Oct 2011 08:18:48 +0200 > Pavel Machek wrote: > > > > > Hi! > > > > > TASK_KILLABLE is often used to put tasks to sleep for quite some time. > > > One of the most common uses is to put tasks to sleep while waiting for > > > replies from a server on a networked filesystem (such as CIFS or NFS). > > > > > > Unfortunately, fake_signal_wake_up does not currently wake up tasks > > > that are sleeping in TASK_KILLABLE state. This means that even if the > > > code were in place to allow them to freeze while in this sleep, it > > > wouldn't work anyway. > > > > > > This patch changes this function to wake tasks in this state as well. > > > This should be harmless -- if the code doing the sleeping doesn't have > > > handling to deal with freezer events, it should just go back to sleep. > > > > I'm pretty sure this will break something; but that does not mean it > > is bad idea, just that it should be merged early and tested a lot. > > > > FWIW, I looked at most of the places in the kernel that do > TASK_KILLABLE sleeps and they look like they'll handle this correctly. > The main one I wasn't sure about was mem_cgroup_handle_oom(), but I > think it'll do the right thing too. I certainly could have missed > something though... > > In any case, would you mind merging this via the linux-pm tree for 3.2? I will push it for 3.2. Thanks, Rafael