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

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Message-ID: <4e00b5df-e9ce-40fa-8da0-9c66fe18bfd7@linux.alibaba.com>
Date: Thu, 15 May 2025 13:50:32 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Nico Pache <npache@...hat.com>, linux-mm@...ck.org,
 linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-trace-kernel@...r.kernel.org
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 mathieu.desnoyers@...icios.com, akpm@...ux-foundation.org,
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 wangkefeng.wang@...wei.com, usamaarif642@...il.com, sunnanyong@...wei.com,
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Subject: Re: [PATCH v7 02/12] introduce khugepaged_collapse_single_pmd to
 unify khugepaged and madvise_collapse



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.

[1] 
https://lore.kernel.org/all/ce5c2314e0368cf34bda26f9bacf01c982d4da17.1747119309.git.baolin.wang@linux.alibaba.com/