Re: [PATCH v4 6/6] mm: madvise: Avoid split during MADV_PAGEOUT and MADV_COLD

David Hildenbrand
2024-03-15T10:35:10Z

> - if (!pageout && pte_young(ptent)) {
> - ptent = ptep_get_and_clear_full(mm, addr, pte,
> - tlb->fullmm);
> - ptent = pte_mkold(ptent);
> - set_pte_at(mm, addr, pte, ptent);
> - tlb_remove_tlb_entry(tlb, pte, addr);
> + if (!pageout) {
> + for (; nr != 0; nr--, pte++, addr += PAGE_SIZE) {
> + if (ptep_test_and_clear_young(vma, addr, pte))
> + tlb_remove_tlb_entry(tlb, pte, addr);
> + }
> }

The following might turn out a bit nicer: Make folio_pte_batch() collect
"any_young", then doing something like we do with "any_writable" in the
fork() case:

...
nr = folio_pte_batch(folio, addr, pte, ptent, max_nr,
fpb_flags, NULL, any_young);
if (any_young)
pte_mkyoung(ptent)
...

if (!pageout && pte_young(ptent)) {
mkold_full_ptes(mm, addr, pte, nr, tlb->fullmm);
tlb_remove_tlb_entries(tlb, pte, nr, addr);
}

--
Cheers,

David / dhildenb