Enabling peer to peer device transactions for PCIe devices

[Serguei Sagalovitch]

On 2016-11-28 04:36 PM, Logan Gunthorpe wrote:
> On 28/11/16 12:35 PM, Serguei Sagalovitch wrote:
>> As soon as PeerDirect mapping is called then GPU must not "move" the
>> such memory.  It is by PeerDirect design. It is similar how it is works
>> with system memory and RDMA MR: when "get_user_pages" is called then the
>> memory is pinned.
> We haven't touch this in a long time and perhaps it changed, but there
> definitely was a call back in the PeerDirect API to allow the GPU to
> invalidate the mapping. That's what we don't want.
I assume that you are talking about "invalidate_peer_memory()' callback?
I was told that it is the "last resort" because HCA (and driver) is not
able to handle  it in the safe manner so it is basically "abort" 
everything.