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

[David Hildenbrand <david@redhat.com>]

> -		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