Re: [RFC PATCH v2 15/19] mm/gup: Introduce vaddr_pin_pages()

From: John Hubbard
Date: Mon Aug 12 2019 - 17:20:22 EST


On 8/12/19 2:00 PM, Ira Weiny wrote:
On Fri, Aug 09, 2019 at 05:09:54PM -0700, John Hubbard wrote:
On 8/9/19 3:58 PM, ira.weiny@xxxxxxxxx wrote:
From: Ira Weiny <ira.weiny@xxxxxxxxx>
...

At one point I wanted to (and had in my tree) a new flag but I went away from
it. Prior to the discussion on mlock last week I did not think we needed it.
But I'm ok to add it back in.

I was not ignoring the idea for this RFC I just wanted to get this out there
for people to see. I see that you threw out a couple of patches which add this
flag in.

FWIW, I think it would be good to differentiate between an indefinite pinned
page vs a referenced "gotten" page.

What you and I have been working on is the former. So it would be easy to
change your refcounting patches to simply key off of FOLL_PIN.

Would you like me to add in your FOLL_PIN patches to this series?

Sure, that would be perfect. They don't make any sense on their own, and
it's all part of the same design idea.

thanks,
--
John Hubbard
NVIDIA