On Sat, Apr 16, 2022 at 11:05:49AM +0800, Miaohe Lin wrote:
> @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
> goto out;
> }
>
> + if (unlikely(!PageUptodate(page))) {
> + pte_t pteval;
> +
> + dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
> + pteval = swp_entry_to_pte(make_swapin_error_entry(page));
> + set_pte_at(vma->vm_mm, addr, pte, pteval);
> + swap_free(entry);
> + ret = 0;
> + goto out;
> + }
> +
> /* See do_swap_page() */
> BUG_ON(!PageAnon(page) && PageMappedToDisk(page));
> BUG_ON(PageAnon(page) && PageAnonExclusive(page));
Totally off-topic, but.. today when I was looking at the unuse path I just
found that the swp bits could have got lost for either soft-dirty and
uffd-wp here? A quick patch attached.
Maybe at some point we should start to have some special helpers for
set_pte_at() when we're converting between present/non-present ptes, so as
to make sure all these will always be taken care of properly.
--
Peter Xu
