Re: [PATCH v3 22/22] thermal/intel_powerclamp: Convert the kthread to kthread worker API

[Jacob Pan]

On Fri, 8 Jan 2016 17:49:31 +0100
Petr Mladek <pmladek@xxxxxxxx> wrote:

> Is the __preempt_schedule() a problem? It allows to switch the process
> when needed. I thought that it was safe because try_to_freeze() might
> have slept as well.
> 
not a problem. i originally thought queue_kthread_work() may add
delay but it doesn't since there is no other work on this kthread.
> 
> > - vulnerable to future changes of queuing work  
> 
> The question is if it is safe to sleep, freeze, or even migrate
> the system between the works. It looks like because of the
> try_to_freeze() and schedule_interrupt() calls in the original code.
> 
> BTW: I wonder if the original code correctly handle freezing after
> the schedule_timeout(). It does not call try_to_freeze()
> there and the forced idle states might block freezing.
> I think that the small overhead of kthread works is worth
> solving such bugs. It makes it easier to maintain these
> sleeping states.
it is in a while loop, so try_to_freeze() gets called. Am I missing
something?

Thanks,

Jacob