[PATCH v4] mm: cma: add a simple kernel module as the helper to test CMA

[Barry Song]

Hi Marek,

2012/7/3 Marek Szyprowski <m.szyprowski at samsung.com>:
> Hello,
>
> On Wednesday, March 07, 2012 12:38 PM Barry Song wrote:
>
>> From: Barry Song <Baohua.Song at csr.com>
>>
>> Any write request to /dev/cma_test will let the module to allocate memory from
>> CMA, for example:
>>
>> 1st time
>> $ echo 1024 > /dev/cma_test
>> will require cma_test to request 1MB(1024KB)
>> 2nd time
>> $ echo 2048 > /dev/cma_test
>> will require cma_test to request 2MB(2048KB)
>>
>> Any read request to /dev/cma_test will let the module to free the 1st valid
>> memory from CMA, for example:
>>
>> 1st time
>> $ cat /dev/cma_test
>> will require cma_test to free the 1MB allocated in the first write request
>> 2nd time
>> $ cat /dev/cma_test
>> will require cma_test to free the 2MB allocated in the second write request
>>
>> Signed-off-by: Barry Song <Baohua.Song at csr.com>
>> ---
>>  tools/cma/Makefile   |   13 +++++
>>  tools/cma/cma_test.c |  140 ++++++++++++++++++++++++++++++++++++++++++++++++++
>
> I'm sorry for such a long delay in processing this patch, but I wanted first to be sure
> that the core CMA code gets into mainline, then I got busy with other dma-mapping
> related stuff.

now CMA stuff has been in mainline, i think it makes more senses if
you involve this while you let people merge CMA because it is a CMA
test component.

>
> IMHO the right place for such code is in drivers/misc instead of tools/cma.
>
> This patch contains a kernel module source code so it should be put with other kernel
> modules. tools/ directory is aimed to contain user space code useful for developing and
> testing Linux kernel.

this one is aiming to test CMA, it should be in tools/ as Michal
Nazarewicz and i have talked about that.
it is not a real driver at all.

>
> Make sure that you also add Greg Kroah-Hartman <gregkh at linuxfoundation.org> on CC:,
> he maintains misc drivers.
>
>> (snipped)
>
> Best regards
> --
> Marek Szyprowski
> Samsung Poland R&D Center

-barry