Re: [PATCH 1/3] mm: set folio swapbacked iff folios are dirty in try_to_unmap_one

[Barry Song]

On Mon, Jan 6, 2025 at 7:40 PM Baolin Wang
<baolin.wang@xxxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 2025/1/6 11:17, Barry Song wrote:
> > From: Barry Song <v-songbaohua@xxxxxxxx>
> >
> > The refcount may be temporarily or long-term increased, but this does
> > not change the fundamental nature of the folio already being lazy-
> > freed. Therefore, we only reset 'swapbacked' when we are certain the
> > folio is dirty and not droppable.
> >
> > Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
> > Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
>
> The changes look good to me. While we are at it, could you also change
> the __discard_anon_folio_pmd_locked() to follow the same strategy for
> lazy-freed PMD-sized folio?

it seems you mean __discard_anon_folio_pmd_locked() is lacking
folio_set_swapbacked(folio) for dirty pmd-mapped folios?
and it seems !(vma->vm_flags & VM_DROPPABLE) is also not
handled properly?

Thanks
barry