Re: [PATCH 1/3] ARM: EXYNOS: pmu: Constify data tables

[Kukjin Kim <kgene.kim@samsung.com>]

On 12/10/13 01:15, Tomasz Figa wrote:
> On Tuesday 10 of December 2013 00:11:40 Daniel Kurtz wrote:
>> Hi Tomasz,
>>
>> Thank you for the reviews.
>>
>> On Dec 9, 2013 5:15 AM, "Tomasz Figa"<t.figa@samsung.com>  wrote:
>>>
>>> Hi Daniel,
>>>
>>> On Thursday 21 of November 2013 02:21:24 Daniel Kurtz wrote:
>>>> These tables are all immutable, make them const to save 4416 bytes of RAM.
>>>>
>>>> size arch/arm/mach-exynos/pmu.o
>>>>     text          data     bss
>>>>      848          4420       4         // before
>>>>     5264             4       4         // after
>>>
>>> I'm not sure where the mentioned saving of RAM is. Moving data between
>>> sections is not supposed to make it use less memory, I believe.
>>
>> You are correct.  This was my misunderstanding from doing too much
>> work with microcontrollers, where .text sections are accessed in place
>> from FLASH for code and const data, but .data memory is copied from a
>> FLASH section to a second RAM section at init for access at runtime.
>> Most modern Linux systems copy/decompress their code and data sections
>> from external storage to RAM anyway, so there is no actual memory
>> savings (except potentially the compiler may be able to optimize a bit
>> more with the const hint).
>>
>>>
>>> Anyway, it's a good practice to mark constant data as const, to disallow
>>> changing them at runtime by mistake, so the patch is fine. Except some
>>> issues I commented on inline.
>>
>> Were there supposed to be inline comments?  I don't see any.
>
> Oops, sorry for this, forgot to remove the last sentence. I initially had
> one question about the constant pointers below, but I read through the
> full code again and answered it myself.
>
> The patch is fine.
>
> Reviewed-by: Tomasz Figa<t.figa@samsung.com>
>
OK, applied 1 to 3 patches into cleanup.

Thanks,
Kukjin