linux-kernel - Re: [PATCH 1/2] mm: mmap: no need to call khugepaged_enter

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Message-ID: <877ckb16xl.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date: Mon, 15 Jan 2024 13:50:30 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: Yang Shi <shy828301@...il.com>
Cc: oliver.sang@...el.com,  riel@...riel.com,  fengwei.yin@...el.com,
  willy@...radead.org,  cl@...ux.com,  akpm@...ux-foundation.org,
  linux-kernel@...r.kernel.org,  linux-mm@...ck.org
Subject: Re: [PATCH 1/2] mm: mmap: no need to call khugepaged_enter_vma()
 for stack

Yang Shi <shy828301@...il.com> writes:

> From: Yang Shi <yang@...amperecomputing.com>
>
> We avoid allocating THP for temporary stack, even tnough
                                                    ~~~~~~
                                                    though?

--
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@...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;