On Mon, Feb 06, 2023 at 10:06:38PM +0800, Yin Fengwei wrote:
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index d6f8f41514cc..93192f04b276 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1162,6 +1162,9 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
>
> vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page);
> void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr);
> +void do_set_pte_range(struct vm_fault *vmf, struct folio *folio,
> + unsigned long addr, pte_t *pte,
> + unsigned long start, unsigned int nr);
There are only two callers of do_set_pte(), and they're both in mm.
I don't think we should retain do_set_pte() as a wrapper, but rather
change both callers to call 'set_pte_range()'. The 'do' doesn't add
any value, so let's drop that word.
> + if (!cow) {
> + folio_add_file_rmap_range(folio, start, nr, vma, false);
> + add_mm_counter(vma->vm_mm, mm_counter_file(page), nr);
> + } else {
> + /*
> + * rmap code is not ready to handle COW with anonymous
> + * large folio yet. Capture and warn if large folio
> + * is given.
> + */
> + VM_WARN_ON_FOLIO(folio_test_large(folio), folio);
> + }
The handling of cow pages is still very clunky.
folio_add_new_anon_rmap() handles anonymous large folios just fine. I
think David was looking at current code, not the code in mm-next.
> + set_pte_at(vma->vm_mm, addr, pte, entry);
> +
> + /* no need to invalidate: a not-present page won't be cached */
> + update_mmu_cache(vma, addr, pte);
> + } while (pte++, page++, addr += PAGE_SIZE, --nr > 0);
There's no need to speed-run this. Let's do it properly and get the
arch interface right. This code isn't going to hit linux-next for four
more weeks, which is plenty of time.
