On 2016-11-23 12:27 PM, Bart Van Assche wrote:
On 11/23/2016 09:13 AM, Logan Gunthorpe wrote:
> IMO any memory that has been registered for a P2P transaction should be
> locked from being evicted. So if there's a get_user_pages call it needs
> to be pinned until the put_page. The main issue being with the RDMA
> case: handling an eviction when a chunk of memory has been registered as
> an MR would be very tricky. The MR may be relied upon by another host
> and the kernel would have to inform user-space the MR was invalid then
> user-space would have to tell the remote application.
Are you aware that the Linux kernel already supports ODP (On Demand
Paging)? See also the output of git grep -nHi on.demand.paging. See
My understanding is that the main problems are (a) h/w support (b)
compatibility with IB Verbs semantic.