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References: <20231221065943.2803551-1-shy828301@gmail.com> <877ckb16xl.fsf@yhuang6-desk2.ccr.corp.intel.com>
In-Reply-To: <877ckb16xl.fsf@yhuang6-desk2.ccr.corp.intel.com>
From: Yang Shi <shy828301@gmail.com>
Date: Tue, 16 Jan 2024 13:39:20 -0800
Message-ID: <CAHbLzkpTuTacnB-zes6H2dgy1Hb3roqkMGgUyrk8ULWf5TQhDA@mail.gmail.com>
Subject: Re: [PATCH 1/2] mm: mmap: no need to call khugepaged_enter_vma() for stack
To: "Huang, Ying" <ying.huang@intel.com>
Cc: oliver.sang@intel.com, riel@surriel.com, fengwei.yin@intel.com, 
	willy@infradead.org, cl@linux.com, akpm@linux-foundation.org, 
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
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On Sun, Jan 14, 2024 at 9:52=E2=80=AFPM Huang, Ying <ying.huang@intel.com> =
wrote:
>
> Yang Shi <shy828301@gmail.com> writes:
>
> > From: Yang Shi <yang@os.amperecomputing.com>
> >
> > We avoid allocating THP for temporary stack, even tnough
>                                                     ~~~~~~
>                                                     though?

Yeah, it is a typo. Thanks for noticing this.

>
> --
> Best Regards,
> Huang, Ying
>
> > khugepaged_enter_vma() is called for stack VMAs, it actualy returns
> > false.  So no need to call it in the first place at all.
> >
> > Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
> > ---
> >  mm/mmap.c | 2 --
> >  1 file changed, 2 deletions(-)
> >
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index b78e83d351d2..2ff79b1d1564 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -2046,7 +2046,6 @@ static int expand_upwards(struct vm_area_struct *=
vma, unsigned long address)
> >               }
> >       }
> >       anon_vma_unlock_write(vma->anon_vma);
> > -     khugepaged_enter_vma(vma, vma->vm_flags);
> >       mas_destroy(&mas);
> >       validate_mm(mm);
> >       return error;
> > @@ -2140,7 +2139,6 @@ int expand_downwards(struct vm_area_struct *vma, =
unsigned long address)
> >               }
> >       }
> >       anon_vma_unlock_write(vma->anon_vma);
> > -     khugepaged_enter_vma(vma, vma->vm_flags);
> >       mas_destroy(&mas);
> >       validate_mm(mm);
> >       return error;