Re: [PATCH V3 12/13] cpufreq: ondemand: Traverse list of policy_dbs in update_sampling_rate()

[Rafael J. Wysocki]

On Mon, Feb 8, 2016 at 2:34 PM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 08-02-16, 14:32, Rafael J. Wysocki wrote:
>> > - * If new rate is smaller than the old, simply updating
>> > - * dbs_tuners_int.sampling_rate might not be appropriate. For example, if the
>> > - * original sampling_rate was 1 second and the requested new sampling rate is 10
>> > - * ms because the user needs immediate reaction from ondemand governor, but not
>> > - * sure if higher frequency will be required or not, then, the governor may
>> > - * change the sampling rate too late; up to 1 second later. Thus, if we are
>> > - * reducing the sampling rate, we need to make the new value effective
>> > - * immediately.
>>
>> The comment still applies.
>
> Why? It talks about the case where we have reduced sampling rate, but
> that's not the case anymore. We *always* update sample_delay_ns now.

But the comment explains *why* we do that, doesn't it?

If it doesn't apply, then why do we need this function at all?

>> Moreover, please extend it to say that this must be called with
>> dbs_data->mutex held (or it looks racy otherwise).
>
> Yeah, that can be done.


OK

Thanks,
Rafael