Re: [PATCH] mm/rmap: remove stale hugetlb check in try_to_unmap_one

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Mon, Aug 31, 2026 at 11:59:12PM +0800, Kunwu Chan wrote:
> On Mon, 31 Aug 2026 08:28:47 +0000 Dev Jain <dev.jain@arm.com> wrote:
>
> > Post commit d4ec5572825a ("mm/rmap: add try_to_unmap_poisoned_hugetlb_one")
> > try_to_unmap_one() cannot be called with a hugetlb folio. Therefore remove
> > the folio_test_hugetlb() check.
>
> Yes, the d4ec5572825 change shows that try_to_unmap() dispatches
> hugetlb folios to try_to_unmap_poisoned_hugetlb_one(),
> so try_to_unmap_one() cannot be called with a hugetlb folio.
>
>
> It would be better to add:
> Fixes: d4ec5572825 ("mm/rmap: add try_to_unmap_poisoned_hugetlb_one")

Nope, let's not thanks.

This isn't a bug.

>
> Reviewed-by: Kunwu Chan <kunwu.chan@gmail.com>
>
> Thanks,
> KunWu
>
> >
> > Signed-off-by: Dev Jain <dev.jain@arm.com>
> > ---
> > Rebase soup - my huge_ptep_get() fixes landed after the refactoring.
> >
> > This patch applies on Linux 7.3-rc1.
> >
> >  mm/rmap.c | 7 ++-----
> >  1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index d1819fd699380..606c8ecf31302 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -2299,11 +2299,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> >  		VM_BUG_ON_FOLIO(!pvmw.pte, folio);
> >
> >  		address = pvmw.address;
> > -		if (folio_test_hugetlb(folio)) {
> > -			pteval = huge_ptep_get(mm, address, pvmw.pte);
> > -		} else {
> > -			pteval = ptep_get(pvmw.pte);
> > -		}
> > +		pteval = ptep_get(pvmw.pte);
> > +
> >  		if (likely(pte_present(pteval))) {
> >  			pfn = pte_pfn(pteval);
> >  		} else {
> > --
> > 2.43.0
> >
> >
>

--
Cheers, Lorenzo