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charset=UTF-8 Date: Wed, 01 Jul 2026 09:33:07 -0400 Message-Id: Subject: Re: [PATCH 4/4] mm/page_alloc: remove set_page_private() in prep_compound_tail() Cc: , , , , , , , , , , , , , , , To: "Lance Yang" , From: "Zi Yan" X-Mailer: aerc 0.21.0 References: <53edcc9b-e89a-440b-9d12-7142a561878e@kernel.org> <20260701122506.77115-1-lance.yang@linux.dev> In-Reply-To: <20260701122506.77115-1-lance.yang@linux.dev> X-ClientProxiedBy: BL1P222CA0013.NAMP222.PROD.OUTLOOK.COM (2603:10b6:208:2c7::18) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) 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: IA0PR12MB8374:EE_|CY8PR12MB7489:EE_ X-MS-Office365-Filtering-Correlation-Id: 292a778f-20d5-40fe-754f-08ded7754a14 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|7416014|376014|1800799024|366016|18002099003|22082099003|4143699003|11063799006|6133799003|56012099006; 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Remove the > > With Vlastimil's suggestion on patch #03, we still expect tail pages to > have 0 ->private when freed, but only check it when check_pages_enabled > is enabled :) > >>> unnecessary subpage->private initialization code in compound page >>> preparation. >>>=20 >>> Signed-off-by: Zi Yan >>> --- >>> mm/internal.h | 1 - >>> 1 file changed, 1 deletion(-) >>>=20 >>> diff --git a/mm/internal.h b/mm/internal.h >>> index 181e79f1d6a2..c96421ce9350 100644 >>> --- a/mm/internal.h >>> +++ b/mm/internal.h >>> @@ -895,7 +895,6 @@ static inline void prep_compound_tail(struct page *= tail, >>> { >>> tail->mapping =3D TAIL_MAPPING; >>> set_compound_head(tail, head, order); >>> - set_page_private(tail, 0); >> >>Do we want another safety check, maybe another VM_WARN_ON_ONCE? > > Right! I think such a check might still be useful. Same old footgun :P > > Cheers, Lance Sure. Will add a VM_WARN_ON_ONCE(tail->private). --=20 Best Regards, Yan, Zi