Messages in this thread | | | Date | Wed, 23 Nov 2011 02:15:11 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation |
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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, Srivatsa S. Bhat
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