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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Harry Yoo , "Matthew Wilcox (Oracle)" , Yu Zhao , Baolin Wang , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: make ref_unless functions unless_zero only Date: Fri, 06 Feb 2026 10:46:05 -0500 X-Mailer: MailMate (2.0r6290) Message-ID: <8D231B3B-C82E-4F71-93B5-8ED272EBBAE0@nvidia.com> In-Reply-To: <20260206133328.426921-1-gladyshev.ilya1@h-partners.com> References: <20260206133328.426921-1-gladyshev.ilya1@h-partners.com> Content-Type: text/plain X-ClientProxiedBy: SJ0PR03CA0085.namprd03.prod.outlook.com (2603:10b6:a03:331::30) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|PH7PR12MB8014:EE_ X-MS-Office365-Filtering-Correlation-Id: da9900e3-231c-4153-7357-08de6596d9aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7416014|7053199007; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?wW5+nDvfT+yWM6e+PGnkHNtWLGlsMYwgH6vcJSZQy0+iVxSfAYmNYf3/zj+2?= =?us-ascii?Q?lmRTvjeX/FrgvrjkeJTNrkA5C5y6JpwW0a9JOsVLLCEZ7STPrDNDPL40NseK?= =?us-ascii?Q?Dfdm6PuVoh/YRgcVCjDE9Phy6JpBJLkSP3TWyVgRZK5oBSgok5+QZ1NHw00O?= =?us-ascii?Q?AAWzqyjosfOolT7HWfIx7FmiIrRy0vKTc6t9UBPm9yv3jBMB2JxaBmD37JLe?= =?us-ascii?Q?IUV6B333AMnHbD4+kOpHA9ku8smQMXPVg5nIPCe9PHinbJ3muiBt8mjKhW2s?= =?us-ascii?Q?LzcfN/lT06fvy3bcNAumE/L5IVAS0zlzQOUJi53FNt496P/AbbylQunxoBL6?= =?us-ascii?Q?5dJRPRD0Fr5k0vmQqwItc0dCqFhFzrLCneoXQuLAx9BuwHPmlTquh4tjDKG+?= =?us-ascii?Q?AH0ELHfgGX4RikvgOEYRL/WBPJK3es4EqCSWYVDzOvzDcMiw/oyclbQsr41d?= =?us-ascii?Q?ujsMRmYIc2gZsyKEHCbH3HDCJW0iOCsQQrLVDsvx69meDDqKR3BEml8ax3EP?= =?us-ascii?Q?iwd3kdR+Um9v291l7y6/WYYhJUJPgjqh8LsWw+k6/LLmD6ZodC83n+XYgIVp?= =?us-ascii?Q?WrphOVo0JVA7zf4YMQJIJ4OadoEaiBWyZR64VByK+8d5i6mKkqdQud6qvfip?= =?us-ascii?Q?1mfueuLFHwIsVlcGwnAZBsVj6+wFUz+fxHeTG+qYceEEWvr08iEiJlTz3Zu9?= =?us-ascii?Q?+tMyCZl09nB5IBXNIxQ6amV0/WN2gS8cl2QDu0oo8D3Tqj6hNSQle+67gOTe?= =?us-ascii?Q?Yi0k3e+ptciIiegx2Jqils+6OXSM33qVcj7o8TvQ8dYjt0JmCuCU33n4fRxq?= =?us-ascii?Q?4Zucywr3XholCGsAU8mlcUF+R02qYXF4NUQaK17qxTIB9RQ6oAbCIMOrITDe?= =?us-ascii?Q?bCufEboxpEW8ZtfQZhXPRWbiBAI9C9wvn8ZfkbEYjVqWuVKL2jm+eS7ixwd4?= =?us-ascii?Q?JkpzR6AXorEvnZZMR537fg4WX7wxj7tFnb+BPKMGYjAqPgZ5GlsadcfmFdto?= =?us-ascii?Q?Z9FHt23sRl8qnRwGg6c35P6JrWH+CNXFgU3PdDW9P5jdNmDMDlTLPyd+G+yH?= =?us-ascii?Q?bKqg2mCUfU3XPuI+5DC052V65ioQyB89iaJyM1JHapvxDze/fY5RqOM/sj/A?= =?us-ascii?Q?T1h4Ka3QK4LBzzonVryAeemUqzdYo190YspthlwzhnbjlTypF72NE+LBqaJb?= =?us-ascii?Q?HolI7s+OuwjVacTxtH9Dpvu0LP4fUM6ZEMas3w81R3Llfsy4ktjq42/i/T2/?= =?us-ascii?Q?NEtrqd3zgj2W+p+HO1aYFKsxogDLud3w287AR4XGFq3TjqJqG5h03ALJ5j6V?= =?us-ascii?Q?pXLFGC+kf4tzXtKMqKBI6ZAlxuuX/CNEyt1w6Ki0YXPdViSKcVj8I02OWuKN?= =?us-ascii?Q?Mwceex15D8BGmMnv5xn7+sgysTzue4QkNUEysBGBRw/2xfsSFaHpRoFNF7Fg?= =?us-ascii?Q?gBASR3MkwBtfYp1/2/gZ1WH33O7r5wNv3DMcpI+ps8kl6Vet7wbzYBdXcgg5?= =?us-ascii?Q?a077nAn8icg8aYs/8QQ+KBTM4jRaDQFiVr8zwaGy3ez+Cb1mievcp6BM+HpN?= =?us-ascii?Q?1UOKG+rSpRg15xQTm2yuSPoWw5raeAyQfEkTiMh35PNxmYL59TRgXB/OwDoG?= =?us-ascii?Q?n/y81hQBeoK7h4cSOYcjcqmOUdqOCvE2VuUSQYLHxFO/w7pNl6HL5kr0KMG6?= =?us-ascii?Q?tos21qrf4u6zThwXrNEWhXlHkLOoWTHOQw3owAqZ5ALipXvx?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: da9900e3-231c-4153-7357-08de6596d9aa X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Feb 2026 15:46:10.6088 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: /o4QPPyUEizcL5j2jM3IofcGaLLsEtPEe/g9owhIU3+8gAFsRwVAG37PPfV/sK52 X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB8014 On 6 Feb 2026, at 8:33, Gladyshev Ilya wrote: > There are no users of (folio/page)_ref_add_unless(page, nr, u) with > u != 0 [1] and all current users are "internal" for page refcounting API. > This allows us to safely drop this parameter and reduce function > semantics to the "unless zero" cases only, which will be optimized in > the following patch. > > If needed, these functions for the u!=0 cases can be trivially > reintroduced later using the same atomic_add_unless operations as before. > > [1]: The last user was dropped in v5.18 kernel, commit 27674ef6c73f > ("mm: remove the extra ZONE_DEVICE struct page refcount"). There is no > trace of discussion as to why this cleanup wasn't done earlier. > > Co-developed-by: Gorbunov Ivan > Signed-off-by: Gorbunov Ivan > Signed-off-by: Gladyshev Ilya > Acked-by: David Hildenbrand (Arm) > --- > include/linux/mm.h | 2 +- > include/linux/page-flags.h | 6 +++--- > include/linux/page_ref.h | 14 +++++++------- > 3 files changed, 11 insertions(+), 11 deletions(-) > Acked-by: Zi Yan Best Regards, Yan, Zi