On Fri, 8 Jan 2016 17:49:31 +0100
Petr Mladek [off-list ref] 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.

quoted

- 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

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