Re: [Patch v2 2/2] mm/khugepaged: remove definition of struct khugepaged_mm_slot

[Nico Pache <npache@redhat.com>]

On Fri, Sep 19, 2025 at 1:37 AM David Hildenbrand <david@redhat.com> wrote:
>
> On 19.09.25 09:12, Wei Yang wrote:
> > Current code is not correct to get struct khugepaged_mm_slot by
> > mm_slot_entry() without checking mm_slot is !NULL. There is no problem
> > reported since slot is the first element of struct khugepaged_mm_slot.
> >
> > While struct khugepaged_mm_slot is just a wrapper of struct mm_slot,
> > there is no need to define it.
> >
> > Remove the definition of struct khugepaged_mm_slot, so there is not
> > chance to miss use mm_slot_entry().
> >
> > Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> > Cc: Lance Yang <lance.yang@linux.dev>
> > Cc: David Hildenbrand <david@redhat.com>
> > Cc: Dev Jain <dev.jain@arm.com>
> > Cc: Kiryl Shutsemau <kirill@shutemov.name>
> > Cc: xu.xin16@zte.com.cn
> > ---
> >   mm/khugepaged.c | 57 ++++++++++++++++++-------------------------------
> >   1 file changed, 21 insertions(+), 36 deletions(-)
> >
> > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > index e019ea2cbab0..88ea92c64bf0 100644
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -103,14 +103,6 @@ struct collapse_control {
> >       nodemask_t alloc_nmask;
> >   };
> >
> > -/**
> > - * struct khugepaged_mm_slot - khugepaged information per mm that is being scanned
> > - * @slot: hash lookup from mm to mm_slot
> > - */
> > -struct khugepaged_mm_slot {
> > -     struct mm_slot slot;
> > -};
> > -
>
> Looking into the details, we remove the last entries from this member in
> d50791c2bee9 ("mm/khugepaged: delete
> khugepaged_collapse_pte_mapped_thps()").
>
> @Nico did you have any use case in one of your scanning-optimizing
> prototypes for khugepaged_mm_slot?

Nope! Im utilizing the scan control struct. This change looks good
with the fix in place

>
> --
> Cheers
>
> David / dhildenb
>