From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757258Ab1KVUw6 (ORCPT ); Tue, 22 Nov 2011 15:52:58 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:52402 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752496Ab1KVUw5 (ORCPT ); Tue, 22 Nov 2011 15:52:57 -0500 From: "Rafael J. Wysocki" To: "Srivatsa S. Bhat" Subject: Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation Date: Tue, 22 Nov 2011 21:55:45 +0100 User-Agent: KMail/1.13.6 (Linux/3.1.0-rc10+; KDE/4.6.0; x86_64; ; ) Cc: Pavel Machek , len.brown@intel.com, tj@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: <20111121173939.9486.38357.stgit@srivatsabhat.in.ibm.com> <201111222132.35984.rjw@sisk.pl> <4ECC09D7.7050601@linux.vnet.ibm.com> In-Reply-To: <4ECC09D7.7050601@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111222155.45481.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, November 22, 2011, Srivatsa S. Bhat wrote: > On 11/23/2011 02:02 AM, Rafael J. Wysocki wrote: > > On Tuesday, November 22, 2011, Srivatsa S. Bhat wrote: > >> On 11/22/2011 05:15 PM, Pavel Machek wrote: > >>> On Mon 2011-11-21 23:25:39, Rafael J. Wysocki wrote: > >>>> On Monday, November 21, 2011, Srivatsa S. Bhat wrote: > >>>>> At some of the early exit points during hibernation (exiting either due > >>>>> to failure or after a successful hibernation test, the memory pre-allocated > >>>>> for hibernation is not freed up. And this is *very* serious, because, during > >>>>> pre-allocation, it could have allocated upto a few *gigabytes* of memory! > >>>>> And hence, if a hibernation fails or even if we run some hibernation tests > >>>>> using the 'pm_test' framework, the system is rendered unstable due to memory > >>>>> becoming signifantly lower. Fix this bug. > >>>> > >>>> While the observation is valid, I'd prefer to do something like the patch > >>>> below. > >>> > >>> The code slowly becomes goto maze :-(. > >>> > >> > >> I agree.. It is already quite a mess. > >> > >>>> @@ -357,12 +357,14 @@ int hibernation_snapshot(int platform_mo > >>>> * successful freezer test. > >>>> */ > >>>> freezer_test_done = true; > >>>> - goto Close; > >>>> + goto Cleanup; > >>>> } > >>>> > >>>> error = dpm_prepare(PMSG_FREEZE); > >>>> - if (error) > >>>> - goto Complete_devices; > >>>> + if (error) { > >>>> + dpm_complete(msg); > >>>> + goto Cleanup; > >>>> + } > >>> > >>> Perhaps dpm_prepare should be changed to clean after itself in the > >>> error case? That is the normal convention AFAICT.... > >>> > >> > >> If the intention here is to merely clean up hibernation_snapshot() code, > >> I would not prefer to change the behaviour of dpm_prepare(), considering > >> things like, what parameter should we pass to dpm_complete(); is the > >> resultant behaviour change in dpm_suspend_start() correct or not; what > >> happens to all the code that uses the nice pair: dpm_suspend_start() and > >> dpm_resume_end() and so on. > >> > >> Perhaps there are bigger issues involved there, since I observed on a brief > >> look that the current code doesn't seem to strictly follow the above > >> convention that whoever called dpm_prepare() should call dpm_complete() > >> upon failure. Or may be its doing the right thing.. I don't know. > >> > >> But anyway, the good news is, even without changing dpm_prepare()'s > >> behaviour, we can clean up quite a bit of code in hibernation_snapshot(), > >> as it is. > >> > >> The first patch below does the cleanup, the second patch fixes the memory > >> leak and applies on top of the first patch. > > > > Wait, wait. These changes can be made in the 3.3 merge window, while I'd > > like the fix the bug _now_. > > > > Does anyone have any _technical_ problem with my patch posted previously > > in this thread? > > > > Technically, your patch is fine :-) > > Acked-by: Srivatsa S. Bhat Thanks! Please feel free to make the cleanup on top of it. Rafael