On 2/23/26 17:08, Gregory Price wrote: > On Mon, Feb 23, 2026 at 09:54:55AM -0500, Gregory Price wrote: >> On Mon, Feb 23, 2026 at 02:07:15PM +0100, David Hildenbrand (Arm) wrote: >>> >>> I'm concerned about adding more special-casing (similar to what we already >>> added for ZONE_DEVICE) all over the place. >>> >>> Like the whole folio_managed_() stuff in mprotect.c >>> >>> Having that said, sounds like a reasonable topic to discuss. >>> >> >> Another option would be to add the hook to vma_wants_writenotify() >> instead of the page table code - and mask MM_CP_TRY_CHANGE_WRITABLE. >> > > scratch all this - existing hooks exist for exactly this purpose: > > can_change_[pte|pmd]_writable() > > Surprised I missed this. > > I can clean this up to remove it from the page table walks.
Sorry for the late reply -- sounds like we can handle this cleaner. But I am wondering: why is this even required? Is it just for "Services that intercept write faults (e.g., for promotion tracking) need PTEs to stay read-only" But that promotion tracking sounds like some orthogonal work to me. What am I missing that this is required in this patch set? (is it just for the special compressed RAM bits?) -- Cheers, David
