linux-kernel - Re: [PATCH 1/2] mm/page_alloc: drop the unnecessary pfn

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Message-ID: <87h6t7s9gu.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date:   Sun, 23 Apr 2023 08:55:45 +0800
From:   "Huang, Ying" <ying.huang@...el.com>
To:     Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc:     <akpm@...ux-foundation.org>, <mgorman@...hsingularity.net>,
        <vbabka@...e.cz>, <mhocko@...e.com>, <david@...hat.com>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] mm/page_alloc: drop the unnecessary pfn_valid() for
 start pfn

Baolin Wang <baolin.wang@...ux.alibaba.com> writes:

> We've already used pfn_to_online_page() for start pfn to make sure
> it is online and valid, so the pfn_valid() for the start pfn is
> unnecessary, drop it.
>
> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>

Thanks!

Reviewed-by: "Huang, Ying" <ying.huang@...el.com>

> ---
>  mm/page_alloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 9de2a18519a1..6457b64fe562 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1512,7 +1512,7 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
>  	/* end_pfn is one past the range we are checking */
>  	end_pfn--;
>  
> -	if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
> +	if (!pfn_valid(end_pfn))
>  		return NULL;
>  
>  	start_page = pfn_to_online_page(start_pfn);