linux-kernel - Re: [PATCH v7 02/12] introduce khugepaged_collapse_single_pmd to unify khugepaged and madvise

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Message-ID: <CAA1CXcAO5OkB=P++89q1VhcoRG6j6JR5K15m9sOaPdKwZ-LEkw@mail.gmail.com>
Date: Fri, 16 May 2025 05:59:24 -0600
From: Nico Pache <npache@...hat.com>
To: Baolin Wang <baolin.wang@...ux.alibaba.com>
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Subject: Re: [PATCH v7 02/12] introduce khugepaged_collapse_single_pmd to
 unify khugepaged and madvise_collapse

On Wed, May 14, 2025 at 11:50 PM Baolin Wang
<baolin.wang@...ux.alibaba.com> wrote:
>
>
>
> On 2025/5/15 11:22, Nico Pache wrote:
> > The khugepaged daemon and madvise_collapse have two different
> > implementations that do almost the same thing.
> >
> > Create khugepaged_collapse_single_pmd to increase code
> > reuse and create an entry point for future khugepaged changes.
> >
> > Refactor madvise_collapse and khugepaged_scan_mm_slot to use
> > the new khugepaged_collapse_single_pmd function.
> >
> > Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> > Signed-off-by: Nico Pache <npache@...hat.com>
> > ---
> >   mm/khugepaged.c | 96 +++++++++++++++++++++++++------------------------
> >   1 file changed, 49 insertions(+), 47 deletions(-)
> >
> > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > index 806bcd8c5185..5457571d505a 100644
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -2353,6 +2353,48 @@ static int khugepaged_scan_file(struct mm_struct *mm, unsigned long addr,
> >       return result;
> >   }
> >
> > +/*
> > + * Try to collapse a single PMD starting at a PMD aligned addr, and return
> > + * the results.
> > + */
> > +static int khugepaged_collapse_single_pmd(unsigned long addr,
> > +                                struct vm_area_struct *vma, bool *mmap_locked,
> > +                                struct collapse_control *cc)
> > +{
> > +     int result = SCAN_FAIL;
> > +     struct mm_struct *mm = vma->vm_mm;
> > +
> > +     if (IS_ENABLED(CONFIG_SHMEM) && !vma_is_anonymous(vma)) {
>
> I've removed the CONFIG_SHMEM dependency[1], please do not add it again.

Sorry I handled the conflict on the removal parts, forgot to handle
the addition part... my bad.
>
> [1]
> https://lore.kernel.org/all/ce5c2314e0368cf34bda26f9bacf01c982d4da17.1747119309.git.baolin.wang@linux.alibaba.com/
>