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Message-ID: <7be41dbb-8eb7-4050-8e25-cd65018416f4@intel.com>
Date: Wed, 10 Jan 2024 09:35:38 +0800
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Subject: Re: [PATCH 1/2] mm: mmap: no need to call khugepaged_enter_vma() for
 stack
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To: Yang Shi <shy828301@gmail.com>, <oliver.sang@intel.com>,
	<riel@surriel.com>, <willy@infradead.org>, <cl@linux.com>,
	<ying.huang@intel.com>, <akpm@linux-foundation.org>
CC: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
References: <20231221065943.2803551-1-shy828301@gmail.com>
From: Yin Fengwei <fengwei.yin@intel.com>
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On 2023/12/21 14:59, Yang Shi wrote:
> From: Yang Shi <yang@os.amperecomputing.com>
> 
> We avoid allocating THP for temporary stack, even tnough
> 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>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.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;