Re: [PATCH v3 1/2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend

From: Saravana Kannan
Date: Thu Jul 17 2014 - 23:25:16 EST


On 07/16/2014 10:35 PM, Viresh Kumar wrote:
On 17 July 2014 01:26, Saravana Kannan <skannan@xxxxxxxxxxxxxx> wrote:
On 07/16/2014 04:16 AM, Srivatsa S. Bhat wrote:

That is, we wanted
to do the kobject cleanup after releasing the hotplug lock, and POST_DEAD
stage was well-suited for that.

I think, this has changed in Saravana's patch, we do it in the PREPARE stage
now.

Not really. We much never do it during hotplug. We only do it when the cpufreq driver unregisters.

This should be easier to see in v4, where I'm breaking up the patches into easier diffs.

Commit 1aee40ac9c8 (cpufreq: Invoke __cpufreq_remove_dev_finish() after
releasing cpu_hotplug.lock) explains this in detail. Saravana, please take
a
look at that reasoning and ensure that your patch doesn't re-introduce
those
deadlock possibilities!


But all of that was needed _because_ we were creating and destroying
policies and kobjs all the time. We don't do that anymore. So, I don't think
any of that applies. We only destroy when the cpufreq driver is
unregistered. That's kinda of the point of this patchset.

Thoughts?

See above.


-Saravana

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