linux-kernel - Re: [PATCH v4 12/24] PM / devfreq: tegra30: Inline all one-line functions

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Date:   Fri, 19 Jul 2019 10:27:16 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 12/24] PM / devfreq: tegra30: Inline all one-line
 functions

On 19. 7. 19. 오전 10:24, Chanwoo Choi wrote:
> On 19. 7. 19. 오전 10:22, Dmitry Osipenko wrote:
>> В Thu, 18 Jul 2019 18:09:05 +0900
>> Chanwoo Choi <cw00.choi@...sung.com> пишет:
>>
>>> On 19. 7. 16. 오후 10:35, Dmitry Osipenko wrote:
>>>> 16.07.2019 15:26, Chanwoo Choi пишет:  
>>>>> Hi Dmitry,
>>>>>
>>>>> I'm not sure that it is necessary.
>>>>> As I knew, usally, the 'inline' is used on header file
>>>>> to define the empty functions.
>>>>>
>>>>> Do we have to change it with 'inline' keyword?  
>>>>
>>>> The 'inline' attribute tells compiler that instead of jumping into
>>>> the function, it should take the function's code and replace the
>>>> function's invocation with that code. This is done in order to help
>>>> compiler optimize code properly, please see [1]. There is
>>>> absolutely no need to create a function call into a function that
>>>> consists of a single instruction.
>>>>
>>>> [1] https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Inline.html
>>>>   
>>>
>>> If you want to add 'inline' keyword, I recommend that 
>>> you better to remove the modified function in this patch
>>> and then just call the 'write_relaxed or read_relaxed' function
>>> directly. It is same result when using inline keyword.
>>
>> That could be done, but it makes code less readable.
>>
>> See the difference:
>>
>> device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
>>
>> writel_relaxed(ACTMON_INTR_STATUS_CLEAR,
>> 	       dev->regs + ACTMON_DEV_INTR_STATUS);
> 
> No problem if you add the detailed comment and you want to use
> the 'inline' keyword.

Basically, I think that 'inline' keyword is not necessary.
But if you want to use 'inline' keyword, I recommend
that call the 'write_relaxed or read_relaxed' function directly
with detailed description. 

> 
>>
>>
>>
> 
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics