Re: [PATCH v2 2/10] cpufreq: governor: Use common mutex for dbs_data protection

From: Viresh Kumar
Date: Sun Feb 07 2016 - 04:31:23 EST


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.

--
viresh