On Thu, May 27, 2021 at 07:08:04PM -0400, Felix Kuehling wrote: > Now we're trying to migrate data to and from that memory using the > migrate_vma_* helpers so we can support page-based migration in our > unified memory allocations, while also supporting CPU access to those > pages. So you have completely coherent and indistinguishable GPU and CPU memory and the need of migration is basicaly alot like NUMA policy choice - get better access locality? > This patch series makes a few changes to make MEMORY_DEVICE_GENERIC pages > behave correctly in the migrate_vma_* helpers. We are looking for feedback > about this approach. If we're close, what's needed to make our patches > acceptable upstream? If we're not close, any suggestions how else to > achieve what we are trying to do (i.e. page migration and coherent CPU > access to VRAM)? I'm not an expert in migrate, but it doesn't look outrageous. Have you thought about allowing MEMORY_DEVICE_GENERIC to work with hmm_range_fault() so you can have nice uniform RDMA? People have wanted to do that with MEMORY_DEVICE_PRIVATE but nobody finished the work Jason
