On Fri, May 28, 2021 at 11:56:36AM -0400, Felix Kuehling wrote: > Am 2021-05-28 um 9:08 a.m. schrieb Jason Gunthorpe: > > 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? > > Yes. For a typical GPU compute application it means the GPU gets the > best bandwidth/latency, and the CPU can coherently access the results > without page faults and migrations. That's especially valuable for > applications with persistent compute kernels that want to exploit > concurrency between CPU and GPU. So why not expose the GPU memory as a CPUless memory node?