On Wed, Aug 16, 2023 at 11:00:36AM -0700, John Hubbard wrote: > On 8/16/23 02:49, David Hildenbrand wrote: > > But do 32bit architectures even care about NUMA hinting? If not, just > > ignore them ... > > Probably not! > > ... > > > So, do you mean that let kernel provide a per-VMA allow/disallow > > > mechanism, and > > > it's up to the user space to choose between per-VMA and complex way or > > > global and simpler way? > > > > QEMU could do either way. The question would be if a per-vma settings > > makes sense for NUMA hinting. > > From our experience with compute on GPUs, a per-mm setting would suffice. > No need to go all the way to VMA granularity. > After an offline internal discussion, we think a per-mm setting is also enough for device passthrough in VMs. BTW, if we want a per-VMA flag, compared to VM_NO_NUMA_BALANCING, do you think it's of any value to providing a flag like VM_MAYDMA? Auto NUMA balancing or other components can decide how to use it by themselves.
