On Jun 28, 2022, at 2:12 PM, Peter Xu <peterx@xxxxxxxxxx> wrote: > ⚠ External Email > > On Tue, Jun 28, 2022 at 09:03:02PM +0000, Nadav Amit wrote: >>> Both shmem & hugetlb support private mappings for all three modes, afaict. >> >> Sorry, let me more clear. I meant private (!VM_SHARED) file-backed memory. > > I normally use "file-backed" to stand for "shmem + hugetlb" in any uffd > context. > > If you meant anything outside shmem/hugetlb for uffd (e.g. on xfs), then we > never support them anyway, do we? > > Hmm.. What am I ultimately missing? You are not missing anything. We just have communication problems. I meant - we do not support uffd+xfs today, but maybe one day we will. I do not know/think of any implications WRITE_HINT should have in such case, but it would be useful to have the option to decide how to handle something like that in the future (and not bind ourselves to certain behavior now).
