Messages in this thread | | | Date | Fri, 28 Jul 2023 15:50:29 -0400 | From | Peter Xu <> | Subject | Re: [PATCH v1 0/4] smaps / mm/gup: fix gup_can_follow_protnone fallout |
| |
On Fri, Jul 28, 2023 at 09:40:54PM +0200, David Hildenbrand wrote: > Hmm. So three alternatives I see: > > 1) Use FOLL_FORCE in follow_page() to unconditionally disable protnone > checks. Alternatively, have an internal FOLL_NO_PROTNONE flag if we > don't like that. > > 2) Revert the commit and reintroduce unconditional FOLL_NUMA without > FOLL_FORCE. > > 3) Have a FOLL_NUMA that callers like KVM can pass.
I'm afraid 3) means changing numa balancing to opt-in, probably no-go for any non-kvm gup users as that could start to break there, even if making smaps/follow_page happy again.
I keep worrying 1) on FOLL_FORCE abuse.
So I keep my vote on 2).
Thanks,
-- Peter Xu
| |