On Sun, Jul 16, 2023 at 6:00 PM Yin, Fengwei <fengwei.yin@xxxxxxxxx> wrote: > > On 7/15/2023 2:06 PM, Yu Zhao wrote: > > There is a problem here that I didn't have the time to elaborate: we > > can't mlock() a folio that is within the range but not fully mapped > > because this folio can be on the deferred split queue. When the split > > happens, those unmapped folios (not mapped by this vma but are mapped > > into other vmas) will be stranded on the unevictable lru. > > This should be fine unless I missed something. During large folio split, > the unmap_folio() will be migrate(anon)/unmap(file) folio. Folio will be > munlocked in unmap_folio(). So the head/tail pages will be evictable always. It's close but not entirely accurate: munlock can fail on isolated folios.
