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Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Baolin Wang" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Usama Arif" , "Gregory Price" , "Ying Huang" , "Alistair Popple" , "Johannes Weiner" , "Qi Zheng" , "Shakeel Butt" , "Kairui Song" From: "Zi Yan" X-Mailer: aerc 0.22.0 References: <20260831-remove-pg_private-v2-0-3668159cd9e8@nvidia.com> <20260831-remove-pg_private-v2-14-3668159cd9e8@nvidia.com> In-Reply-To: <20260831-remove-pg_private-v2-14-3668159cd9e8@nvidia.com> X-ClientProxiedBy: BL1PR13CA0082.namprd13.prod.outlook.com (2603:10b6:208:2b8::27) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|CH8PR12MB9790:EE_ X-MS-Office365-Filtering-Correlation-Id: 9270ab8a-7bd6-4fa8-9de4-08df07cf1c83 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|23010399003|366016|921020|10067099003|56012099006|4143699003|11063799006|22082099003|18002099003; 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All PG_private users are converted. Remove PG_private and > reserve the space as __PG_folio for future use. > > Also update files in Documentation. hugetlbfs_reserv.rst is outdated and > left unchanged. It should be rewritten. > > =20 > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 9b585e68127a2..eb2961ed61018 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -44,10 +44,6 @@ > * Consequently, PG_reserved for a page mapped into user space can indic= ate > * the zero page, the vDSO, MMIO pages or device memory. > * > - * The PG_private bitflag is set on pagecache pages if they contain file= system > - * specific data (which is normally at page->private). It can be used by > - * private allocations for its own usage. > - * > * During initiation of disk I/O, PG_locked is set. This bit is set befo= re I/O > * and cleared when writeback _starts_ or when read _completes_. PG_writ= eback > * is set before writeback starts and cleared when it finishes. > @@ -105,7 +101,7 @@ enum pageflags { > PG_owner_2, /* Owner use. If pagecache, fs may use */ > PG_arch_1, > PG_reserved, > - PG_private, /* If pagecache, has fs-private data */ > + __PG_folio, /* Do not use: reserved for folio identification */ Sashiko asked how to detect leaked filesystem private data during page free time after PG_private is removed. Answer copied from RFC: After the conversion, folio/page should have an elevated refcount whenever ->private is set. That would help detect leaked private data. I tried to enforce ->private needs to be NULL at page free time[1], but that might cause trouble for certain use cases. [1] https://lore.kernel.org/all/20260223032641.1859381-1-ziy@nvidia.com/ --=20 Best Regards, Yan, Zi