On Fri, Jul 12, 2024 at 06:54:22AM +0200, Christoph Hellwig wrote: > This is all purely hypothetical, and I'm happy to just check for it > and reject it for it now. I do know a patch set is cooking to allow mixing ZONE_DEVICE P2P and anon memory in the same VMA ala HMM with transparent migration of ZONE_DEVICE to anon. In this situation userspace will be generating IO with no idea about any P2P/!P2P boundaries. Jason