On Tue, Jul 25, 2017 at 02:19:26PM -0700, Paul E. McKenney wrote: > Some architectures are less precise than others in tracking which > CPUs are running a given process due to ASIDs, though this is > thought to be a non-problem: > > https://marc.info/?l=linux-arch&m=126716090413065&w=2 > https://marc.info/?l=linux-arch&m=126716262815202&w=2 > > Thoughts?
On arm64, we *never* touch mm_cpumask, so it will always be empty. The only thing we could potentially use it for is non-broadcast TLB invalidation if the mm was only active on a single CPU, but when I implemented that we pretty much never hit that case. I was hoping fork()+exec() would trigger it (e.g. scripts), but the scheduler treats both of those as rebalancing points so the temporary ASID before the exec always has two CPUs set in its mask. Will
