From nobody Thu Oct 2 14:25:55 2025 Received: from SN4PR2101CU001.outbound.protection.outlook.com (mail-southcentralusazon11012031.outbound.protection.outlook.com [40.93.195.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4A2730DECC for ; Tue, 16 Sep 2025 12:22:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.195.31 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758025332; cv=fail; b=h35KWdm9RSpSEiEkaOWaXbrDJ0MYnM5Vz3YtWA2J7aSncPevn7BOThKJjiTPzw8awDsAAnNM6l9au2S3fHfyxkpMb3NtZ73oePVwpa1gEp5p9/Fs/vIadZ7HxKgXQKSLFUGf8K3/7gcjn248w/wv3L1TZyLNN4T1RynsCcc6bic= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758025332; c=relaxed/simple; bh=FdYgzGLq58ZhMeVCEARcc5WKbobMR4d6Am0J27fKwMg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=fchiYDl42E4/WnV5Z88Iw0ZuUgeCiHdxUsE9Dhk5zDx+x+Niw3WbpeTQy2/bNPwxdCTP+pJj6MkbpaxFdGPdphos6TReQEmXB4uarsXUP+IulcwYJ8smXmYWqHwev3RA7IATyfB9NETRpeQi3QuI/YTTmLDrj25H+O81OpdwUHA= ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=InWxR95q; arc=fail smtp.client-ip=40.93.195.31 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="InWxR95q" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=lBOQSU31IUWwDWFUjLKi/bDiT8pVtOgkDakdftHj2TpcmShghz4bgfbHGqBOmUjfNSBXiMY78T6Mn8DC8W8QyIQBKKMO29wZczJqbfdJ7lB1genUZPzErCREGItdJfRlgdhrTyXJZIMhsQij5hJ4tel83xrliIbcl+5+Dsv8lR72KtxTJ/wTXR5pRCD+IwI/fJjIXpoCTc17qfAvcYyNxQmyl18p+WdYSVu+TzIWD5LAdqQmN810jCMYyaAlhtfCtRtSZ+k6BPvvuzlQ78I55VMr2wvgNqGEW1QsByhA4Y7FYJ95cGAkKGw+le93+x96kF1k+bqYpTMdjL5K5Dlbxw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=BIpsKIdmS4Vl/4tWlSRRMkEyG87nLGt8+VUyUuUw3p0=; b=yboN5iaDjyJ9CWZLN3zV8p3ua7uCHjpgyC1G6DZOqHuwdGY10Bwc9wOnHn0n/8NZUqyf7UFviKdQX60CB6wwgqxIo+UVicu4kMm1XNPppIY+UpxSgxlytAMeBzRXi5LjJ1OPAXQEtV73MG2rJ/k0ErpkQ5KSe9gtm9KFO0gEkq2Csry8oXhhTfegxtOxfYC1wBdWlVUNsAUypfl2K55/BLTaNwAwjgOk4T/XIT6kM5dpsvCSiejL52cQTG3EQrRnszCAmT68UNVTYYBmlOJqs7UbPDRo14yDyfBPB96zKj46NnKaSeqdjCYIsuLGWiLotVxkF33AybL30mXdYpcbbg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=BIpsKIdmS4Vl/4tWlSRRMkEyG87nLGt8+VUyUuUw3p0=; b=InWxR95qqWke5LZt15ojqNXQFbG/BhuCSIYN9GkHmIhb24saFJcvYTxokEZHsfoFcEB0BFMWdR/Qx9omWKb4kDXyFx00KSnqw2ANB2zQqw0Wj6pgX7TBP4vVz4wKeemgr5m5bhnBtDfnBRZwDJEse3HLiyZ8T4GBMpQ3QdPN/q+1fFqTlUVL8WTzNDXD2lHm80j0XGihJDOKSTd8bfy12m+vxAHgMFH+f1NMuRNJH8opZNKEwWd4zUI0UGArtD5R6fa2ZrpgRc/ybwnDoXJJ+6DNVojKe5b9vhs12zBd8FcQ1dk7aP8uGWd2V+qDYDItqXamy3yPonzl3kco3OMt0g== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH8PR12MB7277.namprd12.prod.outlook.com (2603:10b6:510:223::13) by PH8PR12MB7373.namprd12.prod.outlook.com (2603:10b6:510:217::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9094.22; Tue, 16 Sep 2025 12:22:08 +0000 Received: from PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::3a4:70ea:ff05:1251]) by PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::3a4:70ea:ff05:1251%7]) with mapi id 15.20.9115.018; Tue, 16 Sep 2025 12:22:08 +0000 From: Balbir Singh To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: damon@lists.linux.dev, dri-devel@lists.freedesktop.org, Balbir Singh , David Hildenbrand , Zi Yan , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Oscar Salvador , Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , Ralph Campbell , =?UTF-8?q?Mika=20Penttil=C3=A4?= , Matthew Brost , Francois Dugast Subject: [v6 09/15] mm/memremap: add driver callback support for folio splitting Date: Tue, 16 Sep 2025 22:21:22 +1000 Message-ID: <20250916122128.2098535-10-balbirs@nvidia.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250916122128.2098535-1-balbirs@nvidia.com> References: <20250916122128.2098535-1-balbirs@nvidia.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BYAPR06CA0071.namprd06.prod.outlook.com (2603:10b6:a03:14b::48) To PH8PR12MB7277.namprd12.prod.outlook.com (2603:10b6:510:223::13) 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: PH8PR12MB7277:EE_|PH8PR12MB7373:EE_ X-MS-Office365-Filtering-Correlation-Id: 70a16354-4f8e-4266-b67b-08ddf51ba759 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|7416014|10070799003|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?T0w1eFJxaEI3WVNOMlhEWUhITGRQYm9EdHRzK0JNNVRsSUZGZEZ6cm04aGwx?= =?utf-8?B?ZDE4ZVFDdTFVRVhQRnpPRlZ4Rno5emZuVU1IQy9kMk9kZWI4RjlwRWNMZG13?= =?utf-8?B?bnpqMjlPbDl6ZFNDNkcrdkdCc2t2ZmRyUG9XdnBhb0tOWW5zN1ZuZElTOXZ5?= =?utf-8?B?dkVGQi9Vc2w2SWpFY2ZJVnRrYVZyT2RFNlZZZTNLelVFcXhHaWR4c09xRndP?= =?utf-8?B?SjYvUFNCTVF0emVEaXU4OElHRmxIOHhsTGpRUVhHRnRON045SlRrdlJZbWk2?= =?utf-8?B?ZmtHc1JCWGZHVUxmNmZkMlhRQU5WZldTamNMYktRNnY4NzAzSXNHSWpUeGgr?= =?utf-8?B?d2dud2JiODFtRmJFTVZ6dHl1YS9obUVPSXZIclAyWkRGY29zeGg0aHdTUHdT?= =?utf-8?B?bnNzSGU1dVVONWRkdGtLTVFYN3o2aU9XZFNwWkkzUXFqc2ZpS0JwbGU0by9p?= =?utf-8?B?N1pDT3BJMnlVSmREdHBwT0xBNm0zVVN0QWdKQUttci9kNWRtK0pyc20zcTRX?= =?utf-8?B?VnYyR0hjUlJJZlRBQVpmd3pNQStjODE3c0VDVFhCSlY2VmE2dlVhQ0JTTjQw?= =?utf-8?B?ZExrNHc3UU9WQlZxdDVUSWdleGFrVHNOZGZpVmZzYmpRSnIvN002WTBySHh4?= =?utf-8?B?U0lucTU5RVFsMFE5NHd5aWcvZEZQdUwrTFFkcytnc0YrSzhTalFGVkdjcFFr?= =?utf-8?B?dGYzMWdBb3ZYMDFJV1pSaHhQYnQ5ZC8rVE1mSk5OOTR2MjVRVUtFamJUbXBD?= =?utf-8?B?ZDlBV0JxZWg5aTVEWkRvWWlqRytONlV0WDQwZ3BTVENURHpGcS9sODkzdUpX?= =?utf-8?B?dGFBbjdzUFpJR0MwZm5meWV3N003dDcwcmE2NTRvTE5ZKzlLdWRLZG42dk96?= =?utf-8?B?M1k3V3hTbWRJNlhJaW1yK3JwdzE0VTdWUnJXVXFCZ05TY3pxaDdMbUxLMWVy?= =?utf-8?B?ZmZmVDA5S2ZlMlcyVXUrbGpSS3FpVDVZZXF5VENDcUlYMjN6Nlk5c3RyZEZ2?= =?utf-8?B?cEZDYWdWV2dSTWV1STkxM1dzeDdXOEI4RXNwK2RnNitETGZIOFh1SlVqOFRK?= =?utf-8?B?UHEyaW8xWVhYZitHZFpzbUIvVDdEMmdFVm8yQW1DTnZOdGxQbUEyaWJlR2dF?= =?utf-8?B?UVcwM0N2L2IvMXpxRUM1bGU5czVtSDE1MjhvcXdMaTQ5WXNUL3dSaDhqcnBo?= =?utf-8?B?L1dMREMzSXUxNVlqYjUrQ3VHWWZMc00rYXlTWDFUaVdNTGtyeGtwb3JSTDgw?= =?utf-8?B?dTNKZ3QvVDRWNGU5citvb2VQTmliMkc3Q09yUGYwZk9JMEs2dEF1SHJOdU82?= =?utf-8?B?QVcrWVJEMjBGU0pnOU9MOUtxNzJDYlp2bWlRMitmTHVqOHZHcWxvNGhBREpM?= =?utf-8?B?ZzBFLy9BVThTOG52ZUF3V0NNTmE2SVlwK24vZHpKUTloMFNFb3FDc1ZlcjBx?= =?utf-8?B?dC9qTEdTL2JBcFA1aEJKdE5IWjV2djU5MjB2T0U2QzUzOHlTWWs1eHdBcHNj?= =?utf-8?B?b1hyVzRaVE15SEV0eWhKOEFHTzdPQVBVVy9RaHRQUXpHZWRSem9DYThxVmx4?= =?utf-8?B?Q3Y4azJBdjBvTUZkTExma2hxTEtrdUsvNUJzMzNSMWQwcVM3bTR0NnNaaHRh?= =?utf-8?B?Y2RiTWt2QWtNMUV1OWMyWXdDUStadDU3UDYvMUlkU3lSa29meWhjL2RMMkhG?= =?utf-8?B?TjNCOFJCTnliNmpjTkVZcTdSSmVHeDVvZFFqZlp5TzJxcmZiNlVxelMrM1Aw?= =?utf-8?B?U0NQWmE1YlJ2WGFkVkt6TGM0eThqa0YrWURaSUp1bXE5L2ZWM2JZaTJlMktZ?= =?utf-8?B?UVovbmVkenYxS1ZVRTdmbmQwcGJWR294V2lyRWhRMmF6dittR0Zqc2NqVjhJ?= =?utf-8?B?SklWMUVmeDd5emRVYWJLWU9qVnBQY0hVeFVDVjZ5VTk0bVRmM2xEbk1zZkI2?= =?utf-8?Q?QILcI1laqjc=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH8PR12MB7277.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(7416014)(10070799003)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?R2hVZnRBODNOZEZSRWlRbU4zd3kyd0UwWVhueVRralZSNXdoT2xUdnNmWE1x?= =?utf-8?B?di93YU5taEFDSGhHV2hEdDJRRjdJL1dnNE0xNTd1UE9XYk1JU0xwc3VROTVj?= =?utf-8?B?Z1dkeE1SNjRXUVAvSGV1OWd1UzNPcjdrekNpU24yZmNLZmJwVEtpNGZncUZL?= =?utf-8?B?U281bXdaOWYxTldUdWdYL0doci8rZEZHdzY4OU5iU1JtRytLR1ZibXExY25V?= =?utf-8?B?cG9QWWs0R2FuR2Y4cWJHNjlWeTZCYkhQV29VV0V3WStad2RqUFdIL2N2Q2ha?= =?utf-8?B?aU04ditPQUVnRFlYYTBZQ2kxdTFSN2NWMzBXMGVmUUVqR0dHTG1IUy90UW9l?= =?utf-8?B?SVBlSHlkSW8rOUhFS1NBSUNCYUVoZjhKVm12eFIrekdDUlhENDdNOVFURW5J?= =?utf-8?B?WnoxNExYbWZ0NEd5VWxZQ0U4YzY3NlJDTi9GZnFiVXp5cjY4bWVQdjlmSTlK?= =?utf-8?B?Vk11SkZ6eDI5UWFQQmJOYXB1TjY2M1VnUEFrM0hyVDVSVWVIOVRoVkxyTHI3?= =?utf-8?B?MEpIZVJQQ1FsT2VZdmdLMzQwcFMxRjJmbWpmdkdBRFdXYWoxbEk4TDQzUnh0?= =?utf-8?B?aUR2MHBCa3ZyY1owaUlTTTNHWk56aXNKTkFLeStPUXdtYy9hL21NSk00Uk93?= =?utf-8?B?SU5KSjVzcDA3cjlSRUFvU1RrNUpWajZuSnNlQnVUVmFZT0hOMUJPKzdrdFlk?= =?utf-8?B?K0s2bEFqbktuSXVpc2lwNFhJNzBTTVJjdXB6cWQ0QUtGSnp3ZkJnYXl5ME1Z?= =?utf-8?B?WUgxYTVMTGFvVVp4elYwNVN4TnVMWE92VDhzckdqSVYvR0RZOUdsWFVUOVJi?= =?utf-8?B?QXBpb1RSMmJiUVZaRkk3bXFYR0xFc3dadmlGN0hOZEwwMnd2MlQzU3ZiYXVK?= =?utf-8?B?ZGpBeVp5TFE5c1VieE8rMzloV1czcGZUOHR3Q1BQakRuTnFkMWg5ZlR3M1Zh?= =?utf-8?B?dVdwUmtTOXp6d1k0cDhWN3pkWFFYQjM3TWpzelpyaDdtaEZvSm9YZjZHZi9o?= =?utf-8?B?Rk9QcURKY0Uzeko3c2NPcldhb3BHcSsweTVsYThOR3ZFWWN2UzAveHpOSmJR?= =?utf-8?B?OG84RFlrWmU0dXJTNjkxUUdKTmE1ZVpmcklEcjZtcXBEKy8vTEFSbWtia1dC?= =?utf-8?B?SHl6TmYrVzdFWmtCMnpHYi9jeGhMaWhrTzNZNThTR1RlSGZmS1VTbEUwMEpE?= =?utf-8?B?eldMKzU5V0JaZ2NxSU15UUxldjdmODVtVzNxRzJNNG5BLy9NaVI0LzRRbXQ5?= =?utf-8?B?S3RtTzZPWDl1ZENmMXd2WHo4YzY5OFdMZUY1cE1mRzd6VUV0bE1VV0FlZXN2?= =?utf-8?B?TGNudmRFaUhYbVJObWdWR3lxNldabVcvWlRjdjQyVVJzNEEzWms2d2JpVTJa?= =?utf-8?B?ZTFxdFcrWG5RS1doeXpzeEFDZWkvZWpTbi9VQXFOS0ROUlgvbzBxaHk0TFAw?= =?utf-8?B?NGRURENUOStScUg2aVQ1bzJzYklSeEVFSGVPMEdib2FuSy82SDVUbkppQUJr?= =?utf-8?B?WVF4S2tyQ1g0cWxRR1k2WmdmenRLUWZ4SEd1ajJ4eHBvckplS2pMT2wzNTNC?= =?utf-8?B?MTJyd0xGSmc1bTBoMW5adWVJQVl0VFRTYWJxVG5zWnJacWlFUTRJQ1lXc2ts?= =?utf-8?B?bGZOa0N0WGxzUnlVay9wdFZRYjNSTHJKNjFZZitrTlR5a0QreWNFSzlQL3ZU?= =?utf-8?B?aHlPdzB6cEcvaUMxdFd3T0hFMVNVYktOWlhXTkJZWFNGWk5IWUZoeHk3Vmg4?= =?utf-8?B?VEpKYzY4TVJjYy8vUUhXbzZOU24xYlF4bkFsWE1NZFMzNHpGczZhb2pOcjRo?= =?utf-8?B?R2E0VnVrcXhEc2crc1ZnTEV1SXlSRzNtaXZJdUJGdWJGZytZM3lySGNGRm5z?= =?utf-8?B?TytSdEVoNm5YQzYvM1lOMUNiNGNwQ01IcnUrMEtYL0VYSDk2YnZVL05LbFBL?= =?utf-8?B?ZGYrK2g3N292MTRnWnJHK2RPcUxyMDZxaXMya01CZXZ4TjU2eVNmQ1VWaFNP?= =?utf-8?B?Mk9VZXp2TlphbEhaNE04U3N4VTFCU1FIRGJoUXpsWk5ZcnBZT04rd0Y2OXc1?= =?utf-8?B?b2xlL3pDd3dud0xXT1BDTlNBZ01ZYzJVaEhtOW14eDhuaFlMa1FrN2RvWkdO?= =?utf-8?B?NWJDQnFxVUR3c3dJalNiY0Rxc21wQ3hJZytKcEFZMTk5Z3YyQWhzbWFkYVhV?= =?utf-8?B?bVE9PQ==?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 70a16354-4f8e-4266-b67b-08ddf51ba759 X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB7277.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Sep 2025 12:22:08.0103 (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: cQd3lEVX2kBmks2v3R4jJv+vZhh6go3pEBM8zzOW+gEdmeYAWzjm1jW18DVotr/c9bU592XEhagKk5HdsCkPNA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB7373 When a zone device page is split (via huge pmd folio split). The driver callback for folio_split is invoked to let the device driver know that the folio size has been split into a smaller order. Provide a default implementation for drivers that do not provide this callback that copies the pgmap and mapping fields for the split folios. Update the HMM test driver to handle the split. Signed-off-by: Balbir Singh Cc: David Hildenbrand Cc: Zi Yan Cc: Joshua Hahn Cc: Rakie Kim Cc: Byungchul Park Cc: Gregory Price Cc: Ying Huang Cc: Alistair Popple Cc: Oscar Salvador Cc: Lorenzo Stoakes Cc: Baolin Wang Cc: "Liam R. Howlett" Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lyude Paul Cc: Danilo Krummrich Cc: David Airlie Cc: Simona Vetter Cc: Ralph Campbell Cc: Mika Penttil=C3=A4 Cc: Matthew Brost Cc: Francois Dugast --- include/linux/memremap.h | 29 +++++++++++++++++++++++++++++ include/linux/mm.h | 1 + lib/test_hmm.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 65 insertions(+) diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 75987a8cfc6b..ba95c31a7251 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -100,6 +100,13 @@ struct dev_pagemap_ops { */ int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn, unsigned long nr_pages, int mf_flags); + + /* + * Used for private (un-addressable) device memory only. + * This callback is used when a folio is split into + * a smaller folio + */ + void (*folio_split)(struct folio *head, struct folio *tail); }; =20 #define PGMAP_ALTMAP_VALID (1 << 0) @@ -235,6 +242,23 @@ static inline void zone_device_page_init(struct page *= page) zone_device_folio_init(folio, 0); } =20 +static inline void zone_device_private_split_cb(struct folio *original_fol= io, + struct folio *new_folio) +{ + if (folio_is_device_private(original_folio)) { + if (!original_folio->pgmap->ops->folio_split) { + if (new_folio) { + new_folio->pgmap =3D original_folio->pgmap; + new_folio->page.mapping =3D + original_folio->page.mapping; + } + } else { + original_folio->pgmap->ops->folio_split(original_folio, + new_folio); + } + } +} + #else static inline void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) @@ -268,6 +292,11 @@ static inline unsigned long memremap_compat_align(void) { return PAGE_SIZE; } + +static inline void zone_device_private_split_cb(struct folio *original_fol= io, + struct folio *new_folio) +{ +} #endif /* CONFIG_ZONE_DEVICE */ =20 static inline void put_dev_pagemap(struct dev_pagemap *pgmap) diff --git a/include/linux/mm.h b/include/linux/mm.h index d004fb7d805d..be3e6fb4d0db 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1265,6 +1265,7 @@ static inline struct folio *virt_to_folio(const void = *x) void __folio_put(struct folio *folio); =20 void split_page(struct page *page, unsigned int order); +void prep_compound_page(struct page *page, unsigned int order); void folio_copy(struct folio *dst, struct folio *src); int folio_mc_copy(struct folio *dst, struct folio *src); =20 diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 50e175edc58a..41092c065c2d 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -1653,9 +1653,44 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fau= lt *vmf) return ret; } =20 +static void dmirror_devmem_folio_split(struct folio *head, struct folio *t= ail) +{ + struct page *rpage =3D BACKING_PAGE(folio_page(head, 0)); + struct page *rpage_tail; + struct folio *rfolio; + unsigned long offset =3D 0; + + if (!rpage) { + tail->page.zone_device_data =3D NULL; + return; + } + + rfolio =3D page_folio(rpage); + + if (tail =3D=3D NULL) { + folio_reset_order(rfolio); + rfolio->mapping =3D NULL; + folio_set_count(rfolio, 1); + return; + } + + offset =3D folio_pfn(tail) - folio_pfn(head); + + rpage_tail =3D folio_page(rfolio, offset); + tail->page.zone_device_data =3D rpage_tail; + rpage_tail->zone_device_data =3D rpage->zone_device_data; + clear_compound_head(rpage_tail); + rpage_tail->mapping =3D NULL; + + folio_page(tail, 0)->mapping =3D folio_page(head, 0)->mapping; + tail->pgmap =3D head->pgmap; + folio_set_count(page_folio(rpage_tail), 1); +} + static const struct dev_pagemap_ops dmirror_devmem_ops =3D { .page_free =3D dmirror_devmem_free, .migrate_to_ram =3D dmirror_devmem_fault, + .folio_split =3D dmirror_devmem_folio_split, }; =20 static int dmirror_device_init(struct dmirror_device *mdevice, int id) --=20 2.50.1