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Date:   Thu, 21 May 2020 10:56:44 -0400
From:   Qian Cai <cai@lca.pw>
To:     Yang Shi <yang.shi@linux.alibaba.com>
Cc:     kirill.shutemov@linux.intel.com, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC linux-next PATCH] mm: khugepaged: remove error message when
 checking external pins
Message-ID: <20200521145644.GA6367@ovpn-112-192.phx2.redhat.com>
References: <1589317383-9595-1-git-send-email-yang.shi@linux.alibaba.com>
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On Wed, May 13, 2020 at 05:03:03AM +0800, Yang Shi wrote:
[]
>  mm/khugepaged.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 1fdd677..048f5d4 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -602,12 +602,6 @@ static bool is_refcount_suitable(struct page *page)
>  	if (PageSwapCache(page))
>  		expected_refcount += compound_nr(page);
>  
> -	if (IS_ENABLED(CONFIG_DEBUG_VM) && expected_refcount > refcount) {
> -		pr_err("expected_refcount (%d) > refcount (%d)\n",
> -				expected_refcount, refcount);
> -		dump_page(page, "Unexpected refcount");
> -	}
> -
>  	return page_count(page) == expected_refcount;
>  }

mm/khugepaged.c: In function 'is_refcount_suitable':
mm/khugepaged.c:575:25: warning: variable 'refcount set but not used [-Wunused-but-set-variable]
  int expected_refcount, refcount;
                         ^~~~~~~~ 

--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -572,9 +572,8 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte,
 
 static bool is_refcount_suitable(struct page *page)
 {
-	int expected_refcount, refcount;
+	int expected_refcount;
 
-	refcount = page_count(page);
 	expected_refcount = total_mapcount(page);
 	if (PageSwapCache(page))
 		expected_refcount += compound_nr(page);