linux-kernel - Re: [PATCH 1/6] cpufreq: Use existing stub functions instead of IS

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Message-ID: <225a3a6e-94d8-f801-6388-5ec90ca19e11@linaro.org>
Date:   Mon, 24 Jun 2019 11:37:17 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Eduardo Valentin <edubezval@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:CPU FREQUENCY SCALING FRAMEWORK" 
        <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 1/6] cpufreq: Use existing stub functions instead of
 IS_ENABLED macro

On 24/06/2019 11:30, Rafael J. Wysocki wrote:
> On Monday, June 24, 2019 11:22:19 AM CEST Daniel Lezcano wrote:
>> On 22/06/2019 11:12, Rafael J. Wysocki wrote:
>>> On Fri, Jun 21, 2019 at 3:23 PM Daniel Lezcano
>>> <daniel.lezcano@...aro.org> wrote:
>>>>
>>>> The functions stub already exist for the condition the IS_ENABLED
>>>> is trying to avoid.
>>>>
>>>> Remove the IS_ENABLED macros as they are pointless.
>>>
>>> AFAICS, the IS_ENABLED checks are an optimization to avoid generating
>>> pointless code (including a branch) in case CONFIG_CPU_THERMAL is not
>>> set.
>>>
>>> Why do you think that it is not useful?
>>
>> I agree but I'm not a big fan of IS_ENABLED macros in the code when it
>> is possible to avoid them.
>>
>> What about adding a stub for that like:
> 
> Well,
> 
>> #ifdef CPU_THERMAL
>> static inline int cpufreq_is_cooling_dev(struct cpufreq_driver *drv)
>> {
>> 	return drv->flags & CPUFREQ_IS_COOLING_DEV;
>> }
>> #else
>> static inline int cpufreq_is_cooling_dev(struct cpufreq_driver *drv)
>> {
>> 	return 0;
>> }
>> #endif
> 
> This may as well be defined as
> 
> static inline int cpufreq_is_cooling_dev(struct cpufreq_driver *drv)
> {
> 	return IS_ENABLED(CPU_THERMAL) && drv->flags & CPUFREQ_IS_COOLING_DEV;
> }
> 
> which is fewer lines of code.

Ah yes, even better.

> And I would call it something like cpufreq_thermal_control_enabled().

Ok, thanks!




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