Re: [PATCH v2 3/7] mm/khugepaged: introduce a count_collapse_event() helper

On Wed, Jul 29, 2026 at 3:43 AM David Hildenbrand (Arm)
<[email protected]> wrote:
>
> On 7/15/26 04:59, Nico Pache wrote:
> > Provide a simple helper function to help reduce a often used, and
> > duplicate pattern across the khugepaged code.
> >
> > When collapsing to a PMD we need to record a vm_event and the mTHP_stat
> > event. When doing mTHP collapse we only update the mTHP stat.
> >
> > Reviewed-by: Baolin Wang <[email protected]>
> > Acked-by: Usama Arif <[email protected]>
> > Signed-off-by: Nico Pache <[email protected]>
> > ---
> >  mm/khugepaged.c | 36 ++++++++++++++++++------------------
> >  1 file changed, 18 insertions(+), 18 deletions(-)
> >
> > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > index e92e2b928f17..f65bbe2051b3 100644
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -689,6 +689,14 @@ static inline bool collapse_is_referenced(struct collapse_control *cc, pte_t pte
> >               mmu_notifier_test_young(vma->vm_mm, addr));
> >  }
> >
> > +static void count_collapse_event(unsigned int order, enum vm_event_item vm_event,
> > +             enum mthp_stat_item mthp_event)
> > +{
> > +     if (is_pmd_order(order))
> > +             count_vm_event(vm_event);
> > +     count_mthp_stat(order, mthp_event);
> > +}
> > +
> >  static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
> >               unsigned long start_addr, pte_t *pte, struct collapse_control *cc,
> >               unsigned int order, struct list_head *compound_pagelist)
> > @@ -709,9 +717,8 @@ static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma,
> >               if (pte_none_or_zero(pteval)) {
> >                       if (++none_or_zero > max_ptes_none) {
> >                               result = SCAN_EXCEED_NONE_PTE;
> > -                             if (is_pmd_order(order))
> > -                                     count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
> > -                             count_mthp_stat(order, MTHP_STAT_COLLAPSE_EXCEED_NONE);
> > +                             count_collapse_event(order, THP_SCAN_EXCEED_NONE_PTE,
> > +                                             MTHP_STAT_COLLAPSE_EXCEED_NONE);
>
> That's not how we indent parameters here. Unless my mail client displays it in a
> weird way (doubt).
>
> Same applies to all other cases.
>
> Apart from that LGTM.

Ok sounds good I'll get those fixed and send a new version soon.

>
> --
> Cheers,
>
> David
>