Hi Gioh,
On Wed, 26 Nov 2014, Gioh Kim wrote:
2014-11-25 오후 8:32에 Mel Gorman 이(가) 쓴 글:
On Mon, Nov 24, 2014 at 05:54:14PM -0800, Laura Abbott wrote:
There have been a number of patch series posted designed to improve
various
aspects of CMA. A sampling:
https://lkml.org/lkml/2014/10/15/623
http://marc.info/?l=linux-mm&m=141571797202006&w=2
https://lkml.org/lkml/2014/6/26/549
As far as I can tell, these are all trying to fix real problems with CMA
but
none of them have moved forward very much from what I can tell. The goal
of
this session would be to come out with an agreement on what are the
biggest
problems with CMA and the best ways to solve them.
I think this is a good topic. Some of the issues have been brought up
before
at LSF/MM but they never made that much traction so it's worth revisiting.
I
haven't been paying close attention to the mailing list discussions but
I've been a little worried that the page allocator paths are turning into
a bigger and bigger mess. I'm also a bit worried that options such as
migrating pages out of CMA areas that are about to be pinned for having
callback options to forcibly free pages never went anywhere.
I have two question.
First, is GCMA able to replace CMA? It's news to me.
Yes, it can. GCMA could replace or co-exist and be used selectively with
CMA. You could replace CMA with GCMA by simply changing
cma_declare_contiguous() function call with gcma_declare_contiguous().
I need some time to check GCMA.
1st RFC of GCMA was posted on linux-mm mailing list as Laura linked and
you could get whole code from gcma/rfc/v1 tag of
https://github.com/sjp38/linux.gcma. It would great for me if you could
check it and give me any feedback because GCMA have lots of TODO / Future
plans and 2nd RFC is acively developing already.
Thanks,
SeongJae Park
Second, is CMA popular enough to change allocator path?
Yes, I need it.
But I don't know any company uses it, and nobody seems to have interest in
it.