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Date:   Thu, 25 May 2023 11:24:44 +0300
From:   Mike Rapoport <rppt@kernel.org>
To:     Haifeng Xu <haifeng.xu@shopee.com>
Cc:     akpm@linux-foundation.org, mhocko@suse.com, david@redhat.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] mm/mm_init.c: remove comments in
 zone_spanned_pages_in_node() and zone_absent_pages_in_node()
Message-ID: <20230525082444.GT4967@kernel.org>
References: <20230525040150.1588-1-haifeng.xu@shopee.com>
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On Thu, May 25, 2023 at 04:01:48AM +0000, Haifeng Xu wrote:
> Since commit 03e85f9d5f1f ("mm/page_alloc: Introduce free_area_init_core_hotplug"),
> free_area_init_node() doesn't get called in hotplug path anymore, so
> remove the comments related to it.
> 
> Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
> ---
>  mm/mm_init.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index 7f7f9c677854..cf55bba04b23 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -1174,7 +1174,6 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
>  	unsigned long zone_start_pfn, zone_end_pfn;
>  	unsigned long nr_absent;
>  
> -	/* When hotadd a new node from cpu_up(), the node should be empty */
>  	if (!node_start_pfn && !node_end_pfn)
>  		return 0;

I think it's better to call calculate_node_totalpages only if node actually has 
memory and for node with no memory we just need to make sure all the node
and zone page counts are indeed set to 0.

Then the condition here and in zone_spanned_pages_in_node() can be removed
along with the comment and patch 2 won't be required at all.
  
> @@ -1227,7 +1226,7 @@ static unsigned long __init zone_spanned_pages_in_node(int nid,
>  {
>  	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
>  	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
> -	/* When hotadd a new node from cpu_up(), the node should be empty */
> +
>  	if (!node_start_pfn && !node_end_pfn)
>  		return 0;
>  
> -- 
> 2.25.1
> 
> 

-- 
Sincerely yours,
Mike.