Re: [RFC PATCH 3/5] mm/vma: add support for peer to peer to device vma

[Jason Gunthorpe]

On Wed, Jan 30, 2019 at 11:13:11AM -0700, Logan Gunthorpe wrote:
> 
> 
> On 2019-01-30 10:44 a.m., Jason Gunthorpe wrote:
> > I don't see why a special case with a VMA is really that different.
> 
> Well one *really* big difference is the VMA changes necessarily expose
> specialized new functionality to userspace which has to be supported
> forever and may be difficult to change. 

The only user change here is that more things will succeed when
creating RDMA MRs (and vice versa to GPU). I don't think this
restricts the kernel implementation at all, unless we intend to
remove P2P entirely..

Jason