Hi James, On Thu, Mar 26, 2026 at 04:43:27PM -0700, James Houghton wrote: > On Fri, Mar 6, 2026 at 9:19 AM Mike Rapoport <[email protected]> wrote: > > > > From: "Mike Rapoport (Microsoft)" <[email protected]> > > > > When userspace resolves a page fault in a shmem VMA with UFFDIO_CONTINUE > > it needs to get a folio that already exists in the pagecache backing > > that VMA. > > > > Instead of using shmem_get_folio() for that, add a get_folio_noalloc() > > method to 'struct vm_uffd_ops' that will return a folio if it exists in > > the VMA's pagecache at given pgoff. > > > > Implement get_folio_noalloc() method for shmem and slightly refactor > > userfaultfd's mfill_get_vma() and mfill_atomic_pte_continue() to support > > this new API. > > > > Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> > > I found myself asking why HugeTLB wasn't included here; it's because > we call into hugetlb_mfill_atomic_pte() pretty early. It would be nice > to have HugeTLB implement get_folio_noalloc() and use the same path as > shmem, but we don't have to do that now.
You are welcome to join the effort ;-) > Feel free to add: > > Reviewed-by: James Houghton <[email protected]> Thanks! -- Sincerely yours, Mike.
