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SubjectRe: [PATCH] cpufreq: create per policy rwsem instead of per cpu cpu_policy_rwsem
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On 18 September 2013 12:39, Srivatsa S. Bhat
<srivatsa.bhat@linux.vnet.ibm.com> wrote:
> On 09/17/2013 09:20 PM, Viresh Kumar wrote:

> The code looks good, but the patch doesn't apply properly, because of the code
> change that went in in your patch "cpufreq: Clear policy->cpus bits in
> __cpufreq_remove_dev_finish()".

Hmm.. Because of the number of patches floating now a days, it is getting more
and more complex..

I will sort things out once Rafael starts picking stuff for 3.13..

>> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h

>> + /*
>> + * The rules for this semaphore:
>> + * - Any routine that wants to read from the policy structure will
>> + * do a down_read on this semaphore.
>> + * - Any routine that will write to the policy structure and/or may take away
>> + * the policy altogether (eg. CPU hotplug), will hold this lock in write
>> + * mode before doing so.
>> + *
>> + * Additional rules:
>> + * - Governor routines that can be called in cpufreq hotplug path should not
>> + * take this sem as top level hotplug notifier handler takes this.
>
> I think this comment is obsolete. I don't see the top-level hotplug notifier handler
> (cpufreq_cpu_callback) acquiring the rwsem. Good to fix this comment while we are
> at it, perhaps in a separate patch. (The comment above __cpufreq_remove_dev about
> the policy-rwsem appears to be similarly out of date).

Yeah.. Will get that done, but will send these again only once Rafael is picking
stuff for 3.13..


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