On Thu, Aug 17, 2023 at 07:29:12PM -0700, John Hubbard wrote: > On 8/17/23 17:13, Yan Zhao wrote: > ... > > But consider for GPUs case as what John mentioned, since the memory is > > not even pinned, maybe they still need flag VM_NO_NUMA_BALANCING ? > > For VMs, we hint VM_NO_NUMA_BALANCING for passthrough devices supporting > > IO page fault (so no need to pin), and VM_MAYLONGTERMDMA to avoid misplace > > and migration. > > > > Is that good? > > Or do you think just a per-mm flag like MMF_NO_NUMA is good enough for > > now? > > > > So far, a per-mm setting seems like it would suffice. However, it is > also true that new hardware is getting really creative and large, to > the point that it's not inconceivable that a process might actually > want to let NUMA balancing run in part of its mm, but turn it off > to allow fault-able device access to another part of the mm. > > We aren't seeing that yet, but on the other hand, that may be > simply because there is no practical way to set that up and see > how well it works. > > Hi guys, Thanks a lot for your review and suggestions! I'll firstly try to add a per-mm flag to fix this problem later (but maybe not very soon) Thanks Yan
