linux-kernel - Re: [PATCH v3 2/2] mm/huge_memory: use folio_expected_ref_count() to calculate ref

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9ba7c5bd-cb7f-498a-b829-43d26993bc73@linux.alibaba.com>
Date: Thu, 17 Jul 2025 16:03:16 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Zi Yan <ziy@...dia.com>, Balbir Singh <balbirs@...dia.com>,
 David Hildenbrand <david@...hat.com>, linux-mm@...ck.org
Cc: Andrew Morton <akpm@...ux-foundation.org>, Hugh Dickins
 <hughd@...gle.com>, Kirill Shutemov <k.shutemov@...il.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, Nico Pache <npache@...hat.com>,
 Ryan Roberts <ryan.roberts@....com>, Dev Jain <dev.jain@....com>,
 Barry Song <baohua@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] mm/huge_memory: use folio_expected_ref_count() to
 calculate ref_count.

On 2025/7/15 01:18, Zi Yan wrote:
> Instead of open coding the ref_count calculation, use
> folio_expected_ref_count().
> 
> Suggested-by: David Hildenbrand <david@...hat.com>
> Signed-off-by: Zi Yan <ziy@...dia.com>
> Acked-by: Balbir Singh <balbirs@...dia.com>
> Acked-by: David Hildenbrand <david@...hat.com>
> ---

Looks more readable. Thanks.
Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>

>   mm/huge_memory.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index a7ee731f974f..31b5c4e61a57 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -3735,6 +3735,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   	if (folio_ref_freeze(folio, 1 + extra_pins)) {
>   		struct address_space *swap_cache = NULL;
>   		struct lruvec *lruvec;
> +		int expected_refs;
>   
>   		if (folio_order(folio) > 1 &&
>   		    !list_empty(&folio->_deferred_list)) {
> @@ -3805,11 +3806,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   		     new_folio = next) {
>   			next = folio_next(new_folio);
>   
> -			folio_ref_unfreeze(
> -				new_folio,
> -				1 + ((mapping || swap_cache) ?
> -					     folio_nr_pages(new_folio) :
> -					     0));
> +			expected_refs = folio_expected_ref_count(new_folio) + 1;
> +			folio_ref_unfreeze(new_folio, expected_refs);
>   
>   			lru_add_split_folio(folio, new_folio, lruvec, list);
>   
> @@ -3839,8 +3837,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   		 * Otherwise, a parallel folio_try_get() can grab origin_folio
>   		 * and its caller can see stale page cache entries.
>   		 */
> -		folio_ref_unfreeze(folio, 1 +
> -			((mapping || swap_cache) ? folio_nr_pages(folio) : 0));
> +		expected_refs = folio_expected_ref_count(folio) + 1;
> +		folio_ref_unfreeze(folio, expected_refs);
>   
>   		unlock_page_lruvec(lruvec);
>