On Mon, Jan 13, 2025 at 06:42:46PM -0800, Dan Williams wrote: > Alistair Popple wrote: > > At present mlock skips ptes mapping ZONE_DEVICE pages. A future change > > to remove pmd_devmap will allow pmd_trans_huge_lock() to return > > ZONE_DEVICE folios so make sure we continue to skip those. > > > > Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx> > > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > > This looks like a fix in that mlock_pte_range() *does* call mlock_folio() > when pmd_trans_huge_lock() returns a non-NULL @ptl. > > So it is not in preparation for a future change it is making the pte and > pmd cases behave the same to drop mlock requests. > > The code change looks good, but do add a Fixes tag and reword the > changelog a bit before adding: Yeah, that changelog is a bit whacked. In fact it's not a fix - because mlock_fixup() (the only caller) already filters dax VMAs. So this is really about fixing a possible future bug when we start having PMDs for other types of ZONE_DEVICE pages (ie. private, coherent, etc). So probably I should just roll this into "mm: Allow compound zone device pages". > Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
