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Subject: Re: [PATCH v5 00/11] Introduces new count-based method for tracking
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From: John Hubbard <jhubbard@nvidia.com>
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On 10/3/19 1:36 PM, Leonardo Bras wrote:
> On Thu, 2019-10-03 at 09:29 +0200, Peter Zijlstra wrote:
>> On Wed, Oct 02, 2019 at 10:33:14PM -0300, Leonardo Bras wrote:
...
>> This is something entirely specific to Power, you shouldn't be touching
>> generic code at all.
> 
> Up to v4, I was declaring dummy functions so it would not mess up with
> other archs: http://patchwork.ozlabs.org/patch/1168779/
> 
> But I was recommended to create a generic function that could guide the
> way to archs: http://patchwork.ozlabs.org/patch/1168775/

Yes. And to clarify, I was assuming that the changes to mm/gup.c were 
required in order to accomplish your goals. Given that assumption, I 
wanted the generic code to be "proper", and that's what that feedback
is about.

If you can somehow do it entirely as an arch-specific thing, then probably
that's even better. Although the other questions about file-backed THP
make it sound like some rethinking across the board is required now.


thanks,
-- 
John Hubbard
NVIDIA