Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation | Date | Tue, 22 Nov 2011 21:55:45 +0100 |
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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 <srivatsa.bhat@linux.vnet.ibm.com>
Thanks!
Please feel free to make the cleanup on top of it.
Rafael
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