[Query] CPUFreq: Why do we need policy->user_policy?

[Query] CPUFreq: Why do we need policy->user_policy?

[Viresh Kumar]

Hi Rafael,

I am almost done with cleanup of drivers and am back at cpufreq core.. :)
I got to this structure: struct cpufreq_real_policy;

And I am not able to understand what's the need for this structure?
Can you let me know? Before I try to get rid of it :)

--
viresh

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Rafael J. Wysocki]

On Monday, August 26, 2013 08:00:52 PM Viresh Kumar wrote:
> Hi Rafael,

Hi,

> I am almost done with cleanup of drivers and am back at cpufreq core.. :)
> I got to this structure: struct cpufreq_real_policy;
> 
> And I am not able to understand what's the need for this structure?
> Can you let me know? Before I try to get rid of it :)

Honestly, I don't remember from the top of my head.

Thanks,
Rafael

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Lan Tianyu]

2013/8/26 Rafael J. Wysocki <rjw@sisk.pl>:
> On Monday, August 26, 2013 08:00:52 PM Viresh Kumar wrote:
>> Hi Rafael,
>
> Hi,
>
>> I am almost done with cleanup of drivers and am back at cpufreq core.. :)
>> I got to this structure: struct cpufreq_real_policy;
>>
>> And I am not able to understand what's the need for this structure?
>> Can you let me know? Before I try to get rid of it :)
>
> Honestly, I don't remember from the top of my head.

So far as I know, it stores some user's config and cpufreq_update_policy()
bases on the data in the struct to start a new policy. Cpu thermal driver
（/driver/thermal/cpu_cooling.c）also will its value to update freq policy
when receive a cpufreq policy adjust notification.

>
> Thanks,
> Rafael
>
> --
> To unsubscribe from this list: send the line "unsubscribe cpufreq" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Best regards
Tianyu Lan

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Viresh Kumar]

On 26 August 2013 20:53, Lan Tianyu <lantianyu1986@gmail.com> wrote:
> So far as I know, it stores some user's config and cpufreq_update_policy()
> bases on the data in the struct to start a new policy. Cpu thermal driver
> （/driver/thermal/cpu_cooling.c）also will its value to update freq policy
> when receive a cpufreq policy adjust notification.

Yeah, but how are these different from policy->min/max/policy/governor?
Why do we need to replicate this information?

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Lan Tianyu]

2013/8/27 Viresh Kumar <viresh.kumar@linaro.org>:
> On 26 August 2013 20:53, Lan Tianyu <lantianyu1986@gmail.com> wrote:
>> So far as I know, it stores some user's config and cpufreq_update_policy()
>> bases on the data in the struct to start a new policy. Cpu thermal driver
>> （/driver/thermal/cpu_cooling.c）also will its value to update freq policy
>> when receive a cpufreq policy adjust notification.
>
> Yeah, but how are these different from policy->min/max/policy/governor?
> Why do we need to replicate this information?

>From my understanding.policy->min/max may be modified by some drivers
but the user_policy only store user space config and should not be changed
by other reason.  :)

-- 
Best regards
Tianyu Lan

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Rafael J. Wysocki]

On Tuesday, August 27, 2013 10:04:52 PM Lan Tianyu wrote:
> 2013/8/27 Viresh Kumar <viresh.kumar@linaro.org>:
> > On 26 August 2013 20:53, Lan Tianyu <lantianyu1986@gmail.com> wrote:
> >> So far as I know, it stores some user's config and cpufreq_update_policy()
> >> bases on the data in the struct to start a new policy. Cpu thermal driver
> >> （/driver/thermal/cpu_cooling.c）also will its value to update freq policy
> >> when receive a cpufreq policy adjust notification.
> >
> > Yeah, but how are these different from policy->min/max/policy/governor?
> > Why do we need to replicate this information?
> 
> From my understanding.policy->min/max may be modified by some drivers
> but the user_policy only store user space config and should not be changed
> by other reason.  :)

Yes, that was the original idea IIRC, so separate user settings from stuff that
may be changed internally by the kernel.

Thanks,
Rafael

Re: [Query] CPUFreq: Why do we need policy->user_policy?

[Viresh Kumar]

On 28 August 2013 02:50, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Tuesday, August 27, 2013 10:04:52 PM Lan Tianyu wrote:

>> From my understanding.policy->min/max may be modified by some drivers
>> but the user_policy only store user space config and should not be changed
>> by other reason.  :)
>
> Yes, that was the original idea IIRC, so separate user settings from stuff that
> may be changed internally by the kernel.

Yeah, that's what I understood too now.. Anyway I am going to do some core
cleanups now, drivers are mostly done and will see if something can be done
to get rid of them... Otherwise will keep them as is.