From nobody Wed Oct 1 22:30:41 2025 Received: from BL0PR03CU003.outbound.protection.outlook.com (mail-eastusazon11012038.outbound.protection.outlook.com [52.101.53.38]) (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 F25942D662D for ; Wed, 1 Oct 2025 06:58:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.53.38 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759301916; cv=fail; b=TzIHtrdMj2v3x4ZAqrTMS22pXm9VeZMUPY+zKYv/TV2CswplFWH1ivvnnCPiUT4Edqdx5BEMbbWoUUq9w7UAFcofqyI7tm6H+bGozX5Lcc32lSREN02l5vP0cKTFAw+T+KMf639HJO8Xe63W55ofKb39brZHbKtUZ8q45GUasNY= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759301916; c=relaxed/simple; bh=FAcJ6Wt3fBr2ItjOKZGYxkg6A7A5rzgRp4E6SuetIaM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=F5hwKzOy8egU2Ltdqt1qlaOyYSuVlABp4YKRLJqNbqWIPYc0t2Xb3jyC8OeYdsk5QLoU5PHpeEHWVBPS256QMqPlP4rJmpBp/EkJq8jDpt6t2xfm7MlHlPE7pRLUf8VOTtK76alXEPD6ovPz1/xdmKG5Ipo4TlTizrpQbeKMwYA= 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=HV0DvC+B; arc=fail smtp.client-ip=52.101.53.38 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="HV0DvC+B" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=Aro2po3zULRXmP4PqMPeyhNQp5Lhqu3BDefBLCPi+nkYMk92Vx0nH9XGGkzSDtFhuKccvGGzcXV7JImYZB8GmPGr2fxGyShRdQ5FoytjmvD9z12ucCRcMUv+MPhmEdsrwHXNlty+iPjWIX3zMgv2JWjIM8UNoLifpULO+PbXeYFyqPqyRqvIjPqKjk3AsFpTyMyg1Btn7SXkyjL2WZO56LQz7Klngj0oFf5JsAxw/bLUKjkvhQdRACkg3wI87g71pMluNQ6gXaj8D8xRVRONLShItD4x+DE372VVdrhuxAMJE5bW9DSN8tpmPCcilv+MXwoRQujTecQFAWLb7tX2eg== 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=vOl5M3kp4BIcs6OEkYJUTSmye+VyxZYe9zp20piKQ9I=; b=ixjngslNI51z5V6xa1rVfw90hmj86yT6feludMif85Pc7azf68tEXEwtBBM/zJ/ZutZYge4bdqgqlNMAptZxk4yoXulycJjYYd0fQ/ehp1GuicaIQMyLZ4xIFqVoPQHJIEggbvc3uzjfsNbQ3FpXXQzxMfRD9PKv3q8OCsr/Lln0++V7OzFLwrWtxheE1NN5z/XY71PWSJf8TKIWL68BCeHr9tgoDwaxhQGimfOe6XoEggCiGgdWwEQJIz95S5NQSpcFGKt6qj0+LH9oE8N2b4pw6SeTf+u/2hVDa/Rf9/uM9GDpD+1hkTRei8Y6R9p11GmFII8FaAwWhglK3h50LA== 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=vOl5M3kp4BIcs6OEkYJUTSmye+VyxZYe9zp20piKQ9I=; b=HV0DvC+Bz+aDq/brjbssjubFltaT8xNlb1XJr96t0BW4zG1DZz/QmB3HWGIvnAXZwvodvabSWLODmZgEfKUnWqGxmBVroOaJWYaIa635vSyxFR9dswgNOQoK830q30Vx1xxFXChTb7N8LC/qXVyosGT0uwqVR6mJHLWXES7W5ml46dPCHlT1hLsZC58R+jJkomMedCLQ1gFF96JCPy5As81lcOVZcHVF3izQ7alWrTbuzYqQKTPBsQ+1l4Ps7VShsOr1oLgdfjvvZAmLctjIHcxxXyk9vPAJWV7LDRgLVbcElTXdLm+jalrfu8YzZbcp0VObNPdoj8bqqFdRtkWLwg== 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 CY5PR12MB6299.namprd12.prod.outlook.com (2603:10b6:930:20::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.17; Wed, 1 Oct 2025 06:58:32 +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 15.20.9160.015; Wed, 1 Oct 2025 06:58:32 +0000 From: Balbir Singh To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org Cc: akpm@linux-foundation.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: [v7 08/16] mm/memory/fault: add THP fault handling for zone device private pages Date: Wed, 1 Oct 2025 16:56:59 +1000 Message-ID: <20251001065707.920170-9-balbirs@nvidia.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251001065707.920170-1-balbirs@nvidia.com> References: <20251001065707.920170-1-balbirs@nvidia.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SY6PR01CA0002.ausprd01.prod.outlook.com (2603:10c6:10:e8::7) 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_|CY5PR12MB6299:EE_ X-MS-Office365-Filtering-Correlation-Id: 029b4cae-118b-48cd-6366-08de00b7eec3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|10070799003|1800799024|366016|7416014|376014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?dFhhdGIzb0E4cTVia1JqQ28zSXErYzJKV0REVXZFNXNFOGxWVytVL2NuWHFZ?= =?utf-8?B?cDJ6Yk0zZ3lKRlBFRW93K1VTOHNNeTBtK3lCclZhV3BDUTlhVmM2aG9IV3VR?= =?utf-8?B?NXJJU3lwRmVZRkRyemd4SjYyQm5ZZ0VScDBZVHV3L3FLSittTDBSMmlEa3NX?= =?utf-8?B?Y0ZMSEJMT0c2WGpDT0ZESC9RNkVCUkluZ04vbzA4N2ZPWUFnNVR2T0tvNW5y?= =?utf-8?B?bEt4QVNFbWo1OUk0bkRtWjJ0YTM4bG9IaVNTM2xJbWgrNXFvUmhObUNERzhq?= =?utf-8?B?d2pwNVhWTTdsRDl1ek9paXJFdTk4SGZqU2xhL0pxWkw0aUEvczFNS3JxSjBK?= =?utf-8?B?dUxkcitOZWNOUzlnczRNUUpLV0oxenNwTWUvQVJxTUFwMVJzc2tvaktjaGIy?= =?utf-8?B?UGl0bGhHWHlHejdETXR5Nm9LT3VuNVpnSkpva0RvdTFaeHVYckVsTnZoNG96?= =?utf-8?B?dVJlNUFoNHRqOFQ1Z0pUMCtoTXF4TXlLQUNhcDRRVSs3cEJySkY1WDZZb2to?= =?utf-8?B?ZnhtcThuSk1EK2VPcWxmcHVXdzljZ2c5WEhKazJWWlNZNTJQcGhJZ01Vdndt?= =?utf-8?B?L0dldExKZFZkTUM0OWhjVUpJWm13bU9vdlMrYjZFTGRKRnNQVHJGNnVzYlYz?= =?utf-8?B?NEdLczg0QUJvV1AwZkJBWkxIL0xhMVFOSi9LQmlzWlkzVTBXWnBubDhBQ29y?= =?utf-8?B?Ly96eU1CUU0vbmhubkVTY2p4dUxvNFpDRzdMeGZBNXh2NXBxam1HQ2JzdkMz?= =?utf-8?B?ZU1VQmJkeUtZQjlkRE1PS3NuSUZZaUtPbUdJRWV1d1Q5RmRobDJnRGxjR2Rk?= =?utf-8?B?c0htenpFeDdxWWZoVWNYdmJ6d0hEMmNKOGpuNkxNZHdDU0p5RWxHTElxNDhS?= =?utf-8?B?NnhVL3BFZlhhUHVZeGdYYlgxSzdTOCtqTjdwcFp5aDJENWNkbEpQWllWWndj?= =?utf-8?B?WHhtNzdHK0VVK2ovQS9PdXBDUGFMdkk0ejBMMXVqSElwUlpjVVlrK2JhbHlW?= =?utf-8?B?aktkNkdaaVFET2luTWNRMHUwMGFzeWkvT2FRZVN1YmI2YytlWm5QNEcwbW90?= =?utf-8?B?a3M4UEhjTGpHL24yeG1IVllxRVdWVlhqZmkvZXJtek9DY0pINXN1TEs1NWdq?= =?utf-8?B?N0xHTUZDWnlhQzF1T1JsYTl3UTdhVzk2VXExZUt2MzRvQVNYd0MrcWdSM1VT?= =?utf-8?B?b1Mya2ZSc3lZdDlGcis0UE5nR053ZVVZb2MxRkE3Rm5PZzNMdWxnNjcrdHZH?= =?utf-8?B?bUFONEJtcHMrNWROYVRkMkh6a2RGSzNGMHNFNVRVcC9FTGFta3NyLzhMcW8y?= =?utf-8?B?YUM2ZlNTcHU1eFdYTjVidmdqaTJSOGc5ZTJBaEdsaStEakZOQlFGVUdQYkN5?= =?utf-8?B?Q1REM1VqK25KamlBUktESzBtOWxTMHFwMS9kNm4vUWM0WXRabkFSc3dHb290?= =?utf-8?B?YzFieXRMQ2xzY29kdVJxNGduNWJpNmxIQ3FuK1M2K0JTaUgvOVFXUzlXRkRC?= =?utf-8?B?SkJBRnRBLy9nNWYyWTQxQ2Y1YWxRRnhsMWtGZEZicEpZQXpnQ3BnRWFybkQw?= =?utf-8?B?NjdKb2VFTnBNc1hGTGtycVI0Tjh5eTladGE2VnlhcVcrcmRBSUlxN1hDdUNy?= =?utf-8?B?SlJydWpKcHVUOEpmbXdYWkh4b0l5UWtiUG9Qa1lDcGVMVkdOckttdFl0NGFj?= =?utf-8?B?TWFYTkV1WVJuZkJGZFRRZ0l0RGpqdHY4dFZUYndFc3pZcjhnTjNFU0tIRkp4?= =?utf-8?B?TnRjeWVGS1N4OVhrelVQTzYvWVRHeHpoL001d3lNKzdiSFRDaDZMbk1YVWZV?= =?utf-8?B?dmtETnR3bVJrSHVSeVJKZVJPRGpUYlIrYnZRNzZHRXFHcDlqZm9oVEpYWnQw?= =?utf-8?B?eUlCblg2RllWbGRXYXU0b21kU0Z5WThoRGJWZUNTbHVZN3JFQ1FVK0NxZ3BW?= =?utf-8?Q?Zw3FGLiBy5IVdIg2vxZvE5hzagBVs3UM?= 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)(10070799003)(1800799024)(366016)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?c0owMTloOEJQM09jNTNyR1AvelNLMUNiRlA1QTZnQUhiNHVReENBMjhvTnZr?= =?utf-8?B?bmxsbDhveHJlTHJZOUJzR1NMWjZ0WXU4WWx4QkJlRGt1SFFxM3VRdlhjLzdk?= =?utf-8?B?Zmp0TDVCeU1CYkF1YWpmTWladTNiNFQ0a1dsMVBhVzVwVUFjcEQ5MDFjclVz?= =?utf-8?B?aHJPN1AvbGpVQ1BXT0IrQVk5bFFkR3JVc20yRGtpMWxmOVBZaUFIOUhNKzJJ?= =?utf-8?B?ZEtEOUZtWDFPc3RhdmtOMUd6ZXRxR1NPOVFoMlhkSyt5b25sQ1FXemIrSnNj?= =?utf-8?B?R1UvQjNWNEFHNkRlR1RIVGt3bzlNN2I3bi9TMHBxZWZiSWZJK1dleDhTY3Az?= =?utf-8?B?bTJVek5Cc0VuSEtzR01uRmJmL0RSMUZNdExPTGg2WGsxc1dLVDJRdmV3SjZZ?= =?utf-8?B?d2gyZWxON3UwekRJRlBKRlMyTGN3Y3g2L1lrOFlZRXNsMWpSN0FiOUE2T2dx?= =?utf-8?B?eXN5aktKb2JheXpqeCtwaDBTZEJHa3lHN3FDb3RId0FTT3AycUJySzFxRllq?= =?utf-8?B?NkhQQS82d3pKV0JzblU1ODk0RUxicHFKVW96S0dmNmJYdTZNNlFtNE9IaWs0?= =?utf-8?B?YmJrQ3Z4cnU0WGtVUklnQU02NmpMNjJCbVo1V1ZZbjFadGVXcHFvTE1XMFpI?= =?utf-8?B?UlhkTG9adVpEcklTckxrNDhYK0RUd053a1kxcHF6U3d1bTRtR3ZWcFZLR3N5?= =?utf-8?B?amZqeUk1eU9tcUs5QjFsRzlqVW9rRUpUNGJ4TEVtMldKRXYveDBsa1piamVO?= =?utf-8?B?cVhCZDdVN3k4VVY1VzZHZ3FNVXptV0xVTWNDVlFKak11MnRweFNjdFlQTlVL?= =?utf-8?B?N0xYYUR1MXcwOU5heE1lZjRrSzR0YzZuNEVSdHpQeVlhU1ZDS2JVeFdmaVlR?= =?utf-8?B?dGdXbGZaRzdxTmxnNHR3Y2R4YVkwMzVURVdVSSt3NVBLck9Fd2o2MUcxQjc0?= =?utf-8?B?T0tSOGpFbFVpKzdaekp6YURsTjdTVE15SG9HODAyT0d4V2szbmhoclJjMUR1?= =?utf-8?B?TnorRGxCRERmbE4vNkFrT3Y4YWtXQVFHaWVIekJvY0IvTXBKelZhelFsNUtN?= =?utf-8?B?RFNMelZlbEFnZDBSN25nZk8wMzl0T3pacEF3VVZmYTN4QkZPSk1Wa3pva2Yx?= =?utf-8?B?TDB0c3pDem83OHcxTk96R05TZ28vN29sUWFuSTNKK2tMWGtLVlZ0VERmNjNL?= =?utf-8?B?aFRxWHR6Z2ZoNlpSeTd1bTc0cjNEbkZrOXR3OW8wVzEzU0JGWEZ2blEyT2FM?= =?utf-8?B?Vm5VcE8xV2R6d3ZTckRPNXdaQ0ZvZ2tnOHJIR08vOWNHRmNYeW1vbUJYcmEz?= =?utf-8?B?MnVRQUtXOXZod1U4eWFXY0hDdi9MdThYeDNOMHFHZ3RrelBjeHlHM3A4T0RQ?= =?utf-8?B?OHBtNjQraWQvdndmenJGYWJiUGdSM01jOFpwU016WjRWYUdrZVlyeVNWQ0dn?= =?utf-8?B?dlNpdkw1OEFNRlZuV1VTbkErQmlld0ZRMEN1dEZzeWh4VU0veFNBdSt4Qi9u?= =?utf-8?B?c0R3M2YydGlxZy8vWWlja1dvMHo5cjg5NVZZSFEvNGo5QnYxSkNsK0VsajZQ?= =?utf-8?B?M24rbHduUEZSRFBiYjd2NjRwWlhGaDZOT3Ewc3FQTzFaS3dkeWNKWStWNElP?= =?utf-8?B?L1Q3RjJvcWRvbEx2VU43clcwS3kwOTdNYm9RMHlZUmwzbjcyOG9jbHptQkRN?= =?utf-8?B?TXM5ZUV6Vmh2eFlmcEN5YUhIb1N4UWdCcTkrK3FkcVZsQWZia282Q0FCa2dE?= =?utf-8?B?VCt1Q0VlRkFOTU0zdDVIbGlxOUJ5cUE4UndHL2t0YTd1QXdKV1hMdVlUaTNH?= =?utf-8?B?MUtHYVVVK2hkM2dpL3hiajk2VWtNSnFNVTVQejRvam0raUtBZExGdldrRUlm?= =?utf-8?B?RlVpOTFIU3YzRE1iRkJDTGNqVXA4cnI0QzluZXJENkVDSDk5STFvU1ZQV000?= =?utf-8?B?U2VkS3k1aW1RSUt5Qnl0MjkvbmsrQzRHc24vREJaSWRpWUplSW1TdHJXOUZT?= =?utf-8?B?UTVERmUwNmNwS2Z4bGpVT3BTRmRNNVlIRDA5ZnFQL25EbUdzaWlIck5oUU82?= =?utf-8?B?eWdtMlA3bTRQdFlZcWg1QUltL2QrVWxqcTY0dHJ1M3JraGk1YkwydjlsWS9o?= =?utf-8?B?cndBZHlJcWMxdEEzS3l0Y3o3aDhjRVlOY2ZJck9ISWs2bk9hRm5TQ3VmN3ZP?= =?utf-8?B?dVE9PQ==?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 029b4cae-118b-48cd-6366-08de00b7eec3 X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB7277.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Oct 2025 06:58:32.0701 (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: U0AF0VG6VrnTn74wSpAAA7jXMo4c1pntQNX0MY+AysfMCgZPtdebihL0rzCcmDACtrL60qOSfynOO7Hiok5UdQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6299 Implement CPU fault handling for zone device THP entries through do_huge_pmd_device_private(), enabling transparent migration of device-private large pages back to system memory on CPU access. When the CPU accesses a zone device THP entry, the fault handler calls the device driver's migrate_to_ram() callback to migrate the entire large page back to system memory. Cc: Andrew Morton 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 Signed-off-by: Balbir Singh --- include/linux/huge_mm.h | 7 +++++++ mm/huge_memory.c | 38 ++++++++++++++++++++++++++++++++++++++ mm/memory.c | 5 +++-- 3 files changed, 48 insertions(+), 2 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index f327d62fc985..2d669be7f1c8 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -496,6 +496,8 @@ static inline bool folio_test_pmd_mappable(struct folio= *folio) =20 vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf); =20 +vm_fault_t do_huge_pmd_device_private(struct vm_fault *vmf); + extern struct folio *huge_zero_folio; extern unsigned long huge_zero_pfn; =20 @@ -671,6 +673,11 @@ static inline vm_fault_t do_huge_pmd_numa_page(struct = vm_fault *vmf) return 0; } =20 +static inline vm_fault_t do_huge_pmd_device_private(struct vm_fault *vmf) +{ + return 0; +} + static inline bool is_huge_zero_folio(const struct folio *folio) { return false; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 05c68f5b5fe3..8c95a658b3ec 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1287,6 +1287,44 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struc= t vm_fault *vmf) =20 } =20 +vm_fault_t do_huge_pmd_device_private(struct vm_fault *vmf) +{ + struct vm_area_struct *vma =3D vmf->vma; + vm_fault_t ret =3D 0; + spinlock_t *ptl; + swp_entry_t swp_entry; + struct page *page; + struct folio *folio; + + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + vma_end_read(vma); + return VM_FAULT_RETRY; + } + + ptl =3D pmd_lock(vma->vm_mm, vmf->pmd); + if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd))) { + spin_unlock(ptl); + return 0; + } + + swp_entry =3D pmd_to_swp_entry(vmf->orig_pmd); + page =3D pfn_swap_entry_to_page(swp_entry); + folio =3D page_folio(page); + vmf->page =3D page; + vmf->pte =3D NULL; + if (folio_trylock(folio)) { + folio_get(folio); + spin_unlock(ptl); + ret =3D page_pgmap(page)->ops->migrate_to_ram(vmf); + folio_unlock(folio); + folio_put(folio); + } else { + spin_unlock(ptl); + } + + return ret; +} + /* * always: directly stall for all thp allocations * defer: wake kswapd and fail if not immediately available diff --git a/mm/memory.c b/mm/memory.c index 7e32eb79ba99..59985b88a9b1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6337,8 +6337,9 @@ static vm_fault_t __handle_mm_fault(struct vm_area_st= ruct *vma, vmf.orig_pmd =3D pmdp_get_lockless(vmf.pmd); =20 if (unlikely(is_swap_pmd(vmf.orig_pmd))) { - VM_BUG_ON(thp_migration_supported() && - !is_pmd_migration_entry(vmf.orig_pmd)); + if (is_pmd_device_private_entry(vmf.orig_pmd)) + return do_huge_pmd_device_private(&vmf); + if (is_pmd_migration_entry(vmf.orig_pmd)) pmd_migration_entry_wait(mm, vmf.pmd); return 0; --=20 2.51.0