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SubjectRe: [PATCH v2 2/10] cpufreq: governor: Use common mutex for dbs_data protection
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On Sunday, February 07, 2016 03:01:12 PM Viresh Kumar wrote:
> On 05-02-16, 23:59, Rafael J. Wysocki wrote:
> > One more observation here.
> >
> > If we are able to eliminate dbs_data_mutex from update_sampling_rate(),
> > then cpufreq_governor_dbs() becomes the only user of that lock. Further,
> > if we can guarantee that the governor's ->governor callback will always
> > be invoked under policy->rwsem, dbs_data_mutex becomes unnecessary and
> > may be dropped.
>
> That will be guaranteed with my 7 patches, which I will rebase and send again.
>
> But there are cases where a single dbs_data is going to be used for multiple
> policies and so relying on policy->rwsem isn't going to be sufficient.
>
> But, yeah, we should be able to narrow down the locked area I believe.

That should only be a matter of protecting the gov->gdbs_data object and its
refcount then.

Thanks,
Rafael

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