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From: Lance Yang <ioworker0@gmail.com>
Date: Tue, 7 May 2024 16:38:07 +0800
Message-ID: <CAK1f24=rWdgscbDa6pMqOmTEDOHVLo5NQ=7jOo9TdyJRXahHZg@mail.gmail.com>
Subject: Re: [PATCH v4 2/3] mm/rmap: integrate PMD-mapped folio splitting into
 pagewalk loop
To: David Hildenbrand <david@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>, akpm@linux-foundation.org, 
	willy@infradead.org, sj@kernel.org, maskray@google.com, ziy@nvidia.com, 
	ryan.roberts@arm.com, 21cnbao@gmail.com, mhocko@suse.com, 
	fengwei.yin@intel.com, zokeefe@google.com, shy828301@gmail.com, 
	xiehuan09@gmail.com, libang.li@antgroup.com, wangkefeng.wang@huawei.com, 
	songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org, 
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
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Hey David,

Thanks for reaching out!

On Tue, May 7, 2024 at 4:17=E2=80=AFPM David Hildenbrand <david@redhat.com>=
 wrote:
>
> >>>
> >>> +             if (!pvmw.pte && (flags & TTU_SPLIT_HUGE_PMD)) {
> >>> +                     /*
> >>> +                      * We temporarily have to drop the PTL and star=
t once
> >>> +                      * again from that now-PTE-mapped page table.
> >>> +                      */
> >>> +                     split_huge_pmd_locked(vma, range.start, pvmw.pm=
d, false,
> >>> +                                           folio);
> >>> +                     pvmw.pmd =3D NULL;
> >>> +                     spin_unlock(pvmw.ptl);
> >>
> >> IMO, you should also make the 'pvmw.ptl =3D NULL;' after unlocking as
> >> page_vma_mapped_walk() did, in case some corner case met.
> >
> > Yep, I'll also set pvmw.ptl to NULL here if any corner cases arise.
> >
>
> This series already resides in mm-stable. I asked Andrew to remove it
> for now. If that doesn't work, we'll need fixup patches to address any
> review feedback.

I'll patiently wait Andrew's response, and then submit the next version or
fixup patches accordingly.

Thanks,
Lance

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