linux-kernel - Re: [PATCH] mm: correct the comment when reclaimed pages exceed the scanned pages

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Date:   Thu, 8 Jun 2017 12:47:07 +0800
From:   zhong jiang <zhongjiang@...wei.com>
To:     <minchan@...nel.org>
CC:     <akpm@...ux-foundation.org>, <vinayakm.list@...il.com>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: correct the comment when reclaimed pages exceed the
 scanned pages

On 2017/6/7 16:31, zhongjiang wrote:
> The commit e1587a494540 ("mm: vmpressure: fix sending wrong events on
> underflow") declare that reclaimed pages exceed the scanned pages due
> to the thp reclaim. it is incorrect because THP will be spilt to normal
> page and loop again. which will result in the scanned pages increment.
>
> Signed-off-by: zhongjiang <zhongjiang@...wei.com>
> ---
>  mm/vmpressure.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
> index 6063581..0e91ba3 100644
> --- a/mm/vmpressure.c
> +++ b/mm/vmpressure.c
> @@ -116,8 +116,9 @@ static enum vmpressure_levels vmpressure_calc_level(unsigned long scanned,
>  
>  	/*
>  	 * reclaimed can be greater than scanned in cases
> -	 * like THP, where the scanned is 1 and reclaimed
> -	 * could be 512
> +	 * like reclaimed slab pages, shrink_node just add
> +	 * reclaimed page without a related increment to
> +	 * scanned pages.
>  	 */
>  	if (reclaimed >= scanned)
>  		goto out;
Hi, minchan

what  suggstion about  the patch

Thanks
zhongjiang