Re: [RFC PATCH] PM, freezer: Don't thaw when it's intended frozen processes

From: Kyungmin Park
Date: Mon May 11 2015 - 00:29:07 EST


On Sat, May 9, 2015 at 12:25 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello, Kyungmin.
>
> On Fri, May 08, 2015 at 09:04:26AM +0900, Kyungmin Park wrote:
>> > I need to think more about it but as an *optimization* we can add
>> > freezing() test before actually waking tasks up during resume, but can
>> > you please clarify what you're seeing?
>>
>> The mobile application has life cycle and one of them is 'suspend'
>> state. it's different from 'pause' or 'background'.
>> if there are some application and enter go 'suspend' state. all
>> behaviors are stopped and can't do anything. right it's suspended. but
>> after system suspend & resume, these application is thawed and
>> running. even though system know it's suspended.
>>
>> We made some test application, print out some message within infinite
>> loop. when it goes 'suspend' state. nothing is print out. but after
>> system suspend & resume, it prints out again. that's not desired
>> behavior. and want to address it.
>>
>> frozen user processes should be remained as frozen while system
>> suspend & resume.
>
> Yes, they should and I'm not sure why what you're saying is happening
> because freezing() test done from the frozen tasks themselves should
> keep them in the freezer. Which kernel version did you test? Can you
> please verify it against a recent kernel?

The kernel 3.10 is not working as expected, but right the latest
kernel is working correctly.

I see I'll check what's different and which are modified.

Thank you,
Kyungmin Park
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