linux-kernel - Re: [PATCH] mm/hugetlb: remove a meaningless if statement in gigantic page initialization

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Date:   Tue, 2 Feb 2021 11:06:09 +0100
From:   David Hildenbrand <david@...hat.com>
To:     yanfei.xu@...driver.com, mike.kravetz@...cle.com,
        akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/hugetlb: remove a meaningless if statement in gigantic
 page initialization

On 02.02.21 11:12, yanfei.xu@...driver.com wrote:
> From: Yanfei Xu <yanfei.xu@...driver.com>
> 
> Gigantic page is a compound page and its order is more than 1.
> Thus it must be available for hpage_pincount. Let's remove this
> meaningless if statement.
> 
> Signed-off-by: Yanfei Xu <yanfei.xu@...driver.com>
> ---
>   mm/hugetlb.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index a3e4fa2c5e94..73d602f8c7e2 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1501,9 +1501,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order)
>   		set_compound_head(p, page);
>   	}
>   	atomic_set(compound_mapcount_ptr(page), -1);
> -
> -	if (hpage_pincount_available(page))
> -		atomic_set(compound_pincount_ptr(page), 0);
> +	atomic_set(compound_pincount_ptr(page), 0);
>   }
>   
>   /*
> 

I can spot similar handling in destroy_compound_gigantic_page(). If this 
is correct (which I think it is), we should tackle both occurrences at once.

-- 
Thanks,

David / dhildenb