Re: [LSF/MM TOPIC] Discuss least bad options for resolving longterm-GUP usage by RDMA

From: Christopher Lameter
Date: Tue Feb 12 2019 - 11:39:46 EST

On Mon, 11 Feb 2019, John Hubbard wrote:

> But anyway, Jan's proposal a bit earlier today [1] is finally sinking into
> my head--if we actually go that way, and prevent the caller from setting up
> a problematic gup pin in the first place, then that may make this point sort
> of moot.

Ok well can be document how we think it would work somewhere? Long term
mapping a page cache page could a problem and we need to explain that

> > ie indicate to the FS that is should not attempt to remap physical
> > memory addresses backing this VMA. If the FS can't do that it must
> > fail.
> >
> Yes. Duration is probably less important than the fact that the page
> is specially treated.