From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM02-SN1-obe.outbound.protection.outlook.com (mail-sn1nam02on2087.outbound.protection.outlook.com [40.107.96.87]) (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 6F77826C3A0 for ; Tue, 5 Aug 2025 10:27:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.96.87 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754389666; cv=fail; b=GjsH/esfIY5AUNYR5vybYVF402oFaFKAqCdw45Q17xblZSZjxQxd7cQPdkxJPiB6mvHJ/z8xyfghwCGwhYxDqxCjPIc8LWIzvJ0uWMz2WGPG8pe5HfVkcvDSS9rAl1EV6tFVyx8d8HPjqRf3gKxkTa8GGLFF4BI1N27orJfaM68= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754389666; c=relaxed/simple; bh=UYhEkvRR13tRzV4JycJy/QH27d5YzzMgXTgjPvtOLQQ=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=pTTYp+8ALqUj5WWVhUB9YIDkEOxrEosaGxl7WlnaHuiIq3BNVPhOfNRX8waWizSy7FqU0tV1PwYOWhAhm3LkCaWz4xqd4A1MuiXJF1x0tBgOv3TFf4EoPTC9u0BQR+6CbzyFBJfMoFtFBrXdCGrBy/Jc2FKJkexeYxYI9iCbpwI= 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=aaTk5zTQ; arc=fail smtp.client-ip=40.107.96.87 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="aaTk5zTQ" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=fPp3T8RY+e/OXYGy87n49eba3updEh49WZgawRJOBwwLk3GpeeQerY0QnBF32mEmtKk9pfDVmxt9fbA9hUWj8L9FsYiyl+1qyymCdAJhPK2DjpUxkHOWFD9qBwHOYtddnGtKFBo515S8aPWqVcQfKoZHOv4EO+21eDnae4DAAvqQ8E/Kd34MHU/esVwC71ox24CQ4rpg7FoTvhD4ympongkpdyafcsi0owkh+xSE+SXi/gQ3tPkIaCsGsxFugHJTZiSeI+8VlONUke/WLGBGJfUfSkYX5rsEqFq1smelO6aHUn9yq3flAFNMW3VQx6b+tslNSUVRzaXvE9hU4nDJgA== 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=dcg7leytIasRmVhVrpDGy1XsrLFo3CkkQKe9zDjABl0=; b=HhNaAfdzR/SKK6NHZOoLn1goSG61kM9xdpoZsuzC2heawNyOK7TJXNBCGi36YS/D3XQSz6CfdUmXE8SyD1q0h78oY0Sisl2RR97HjexZOnwaTYTUBZBY/HvUq1CDeKe21TfXgxq1BkmSQcNq/mH80q60waW+/CXzYjbfBYtdzaPCAGg0bmXT6aqxLXLyuwY79AYhgVeRszdcH9/aUWE1R8oNgdb4/N4sD/lDp0iEzko2UaWHwsceUfZjrx8ZsAlTPaYdxzKmtbUfy/SvOM+UKLQMYFqjlYkZ/u6Kj4Yi+hOKYRyajP92+jwDkJBMu7zgeGOOOxhKqb9F2pvkanJZZw== 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=dcg7leytIasRmVhVrpDGy1XsrLFo3CkkQKe9zDjABl0=; b=aaTk5zTQXytMPxCrB/Bim4Sgn4JpwNZOjfAE1kwQ2Wv5+HWxBlKXvEFTCl+wnCqLo6698E/VxEVy/zxrHckpSl9R2xoOKlqob7NM698ewEVASbPIQH67k6yTkxcdMNAwOk8iCpC6HdoEe9XXY87yj7G/nqpLDiYzOmC5a9eU1POGITINJN60MfxCqwVH7sz0gfaz5VUETQ3vH5/fzIkYsPjppaUqVDhpVaZJHPBMfJJN9fW7uStJK6G0OtvrEbIkBb9aCqkp/CSawxBfqxyhS30ytj7krtVKS8jAVAPFEFFFJrjv+YL8g2urvnU9frz5kyXtUs8zuWAefTlkT8WFeQ== 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 SN7PR12MB8789.namprd12.prod.outlook.com (2603:10b6:806:34b::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8989.20; Tue, 5 Aug 2025 10:27:39 +0000 Received: from PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::3a4:70ea:ff05:1251]) by PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::3a4:70ea:ff05:1251%5]) with mapi id 15.20.8989.018; Tue, 5 Aug 2025 10:27:38 +0000 Message-ID: Date: Tue, 5 Aug 2025 20:27:32 +1000 User-Agent: Mozilla Thunderbird Subject: Re: [v2 02/11] mm/thp: zone_device awareness in THP handling code To: =?UTF-8?Q?Mika_Penttil=C3=A4?= , Zi Yan Cc: David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Karol Herbst , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Shuah Khan , Barry Song , Baolin Wang , Ryan Roberts , Matthew Wilcox , Peter Xu , Kefeng Wang , Jane Chu , Alistair Popple , Donet Tom , Matthew Brost , Francois Dugast , Ralph Campbell References: <20250730092139.3890844-1-balbirs@nvidia.com> <11ee9c5e-3e74-4858-bf8d-94daf1530314@redhat.com> <14aeaecc-c394-41bf-ae30-24537eb299d9@nvidia.com> <71c736e9-eb77-4e8e-bd6a-965a1bbcbaa8@nvidia.com> <47BC6D8B-7A78-4F2F-9D16-07D6C88C3661@nvidia.com> <2406521e-f5be-474e-b653-e5ad38a1d7de@redhat.com> <920a4f98-a925-4bd6-ad2e-ae842f2f3d94@redhat.com> <196f11f8-1661-40d2-b6b7-64958efd8b3b@redhat.com> <087e40e6-3b3f-4a02-8270-7e6cfdb56a04@redhat.com> Content-Language: en-US From: Balbir Singh In-Reply-To: <087e40e6-3b3f-4a02-8270-7e6cfdb56a04@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SJ0PR13CA0167.namprd13.prod.outlook.com (2603:10b6:a03:2c7::22) 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_|SN7PR12MB8789:EE_ X-MS-Office365-Filtering-Correlation-Id: cce6c625-6ff5-4597-3e6c-08ddd40ab372 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|376014|7416014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?Y2dUTkZVaVdNT1Y2Kzhxd1Z0aWV6Um5iajRqUmFTcXF4clFKaXovVlNEems4?= =?utf-8?B?N2l0cENJNFlaR2s2Q2UyUDRuVkFLTjltMlRRU0V2eHluQ1JxSW9mNjFTZVNr?= =?utf-8?B?Sk1KaEtYSmM2N1FCZkc1NGoyZERvcXFFaEdoMnYrS215blZDQ0NjeVdKaHgw?= =?utf-8?B?YzV3ZXljZGtudjZYRjhWRDNPL3k1OHcya05sNU0wVytXZXFHLzdteUxrN1dY?= =?utf-8?B?NlVmRTZXemhCZzNGVFREcVNRdlZySitRRENYR1AxL0k2SUg1L2FEcGlvYWN0?= =?utf-8?B?ZVVwZVlLRUVjY1cxTGVxNjMwV25HWTUwVlVrYVVaak9BaHZKSkhMaXk2cnlp?= =?utf-8?B?TkdLdFhjb01tSms0Y056a1c2cm0wUzl5U01ZTUZacFFVSXNYaVlzYVM3bFZs?= =?utf-8?B?WnBpQS9RZmpWVzhQOEJzdFFtaWJVRFNya29Fd284UDcxRkRheUIyNHRybEZy?= =?utf-8?B?OWV4bGRnbFJ4NSttT0JrVHpUMWpFNGhJR3dBM2ljWGdhc0xGRHZlS1dKMzEv?= =?utf-8?B?ZEFFN1ViZHJoNFJkOXFqd2g4OWpuMG9TM3FyL1JWMnZ4UHFSak5iSkgvc0tp?= =?utf-8?B?c09VUXlCejltWTc3Q1Z3Q3J6TDlZa2VNRUptbVJnbGI2T0F0cjF3aUhpSkRE?= =?utf-8?B?WFRnMUl5bHlXVDZFcnBSWjAvR1ljY280ZGtxNDFPMmgwMmI3Q0c3OTB6ZmlL?= =?utf-8?B?cUpZRG93NzJWeWlsQ3BTL0N4cWxDMmgvYXY1MDlVYWJCdDdUUE81c2tXUzYw?= =?utf-8?B?L09yaWZraUhVam1ZTlhCbG8zQzdUVUVUYi90cnlyMEJtV1R5QzBOZVRkcUhI?= =?utf-8?B?TTIwZVFGelNzbEFtSHFEajJDbGFUWkRtOXBMUVBlckxXNXBhaGpLaWZsbGJU?= =?utf-8?B?WEtrTi9WMVErLzFTUVJzWEtjQzIrQU92c0NrOENKUlAvc0NZNDRkalBsUXJn?= =?utf-8?B?Qk43RkdtbTBrR2dOTndDZGJhSXZQUDlJYUxJQTdSK3Q4SHF1OGJiUFFFWWY1?= =?utf-8?B?OUg1Y0VwN3E4RVd6RlhiTGFTbGNWcWpzL21yQnk5KzNFQVR3Q0Z4amVNV3J4?= =?utf-8?B?QnFsWTNzcDdoS1M1MFF0UHBScnY3MEFZY095WXRXNXhiMkdkT25rMXhEdEdx?= =?utf-8?B?Z0NhaXlUakhOS2MySHFUQllRNVFQWTRtZFhaVC9Ha2JGeDhvL3lrcFMvZFFI?= =?utf-8?B?SUlCbi9lM2J5d1doUk9Vd3IzRWpTVFpIYTAwVy8rbU0ySTVJaXAxRUFTc0VV?= =?utf-8?B?RDJ4aGZyZ0w5ejZrUStwQVF4WHhJaWMvQkthT1pzWVY2S2ZKMEtmdVFPMWE4?= =?utf-8?B?d01SeThvVDFhdDZhNzYzb3NvTHFOa292M2UxRk5PSmNDRGtkTUxHVGEzL1ly?= =?utf-8?B?Y0Vmd2hlT29uVDllbC94VW9nU1pBRWdsWWVXNkU5ZDJNRlJrRG9NbXIyUHN5?= =?utf-8?B?QnNnSXdiTWU0bVlIRERQenlHb1FlcC83UE5odVFnOVorN2hYb05ScWpza3hl?= =?utf-8?B?MzZtVGlaSDAyaStDTXdyS09kKzU5Sk9PQ3JER0FsaXFpOG56cllrUnlmNE5k?= =?utf-8?B?N0FIbzEyVjBqamRDdnZna1RSSi9DTHBJZ1ovSC9QL0JHVE1TMUt5dDZFZXNh?= =?utf-8?B?TXJOaHdBMkdOdEZic2JYaTREdXltOThVd05pQldGUTJlQXpmeGRzZ2thMnNq?= =?utf-8?B?UGxuam0zNjM0a0Z4eFk3MTBWUUUya2kzWG14VjlDaXdyWlpGdENHWWM3RlBS?= =?utf-8?B?WjF3R29taTFwNzZlUm52VkZKVmdvSCtsOW4rZC92V2xob1J5SjlLaW84NjBN?= =?utf-8?B?NEp1OUNoTmlhbUNvRDA1aGRkTUw5S1dkVk9qaFpjclgrVzkzN296MVRvd1Jn?= =?utf-8?B?T3JmN0JiR2tFUXNQYjNUL0JmUFpEREc4ZTVmNkdIclVVSVNKVDArL0lQM2lV?= =?utf-8?Q?xgTLvCFKP8I=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)(366016)(1800799024)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?cVJWUThDc0diaU1QS25xdkYzVFN3ZmdERFEra0hVcmdCT0pDZVFKai9EakRJ?= =?utf-8?B?T24zOUh2d1lRR1VuK1FMS0k1WUpKMFJUR0dOQXdNRGYydnEzRUVyK0QzYURu?= =?utf-8?B?OFNlS2pUNmh1MVorZG1QMmZmb2VhRjNTdXNxZENWMmVSM3BsRVpmemRhcVFS?= =?utf-8?B?U1QwMHZMMFlPeFN0cTlBNmtHNkM0MTNVdmNkVUtkMDVRWW8rWmJYdVNMWENU?= =?utf-8?B?NE1rT3M3QTdGekR0SzV2UVZPYjNJT3ZoWndFSkk5dGQyNEFsc08rLzRKRDg1?= =?utf-8?B?QWo4dktOVWx6dFd3OW02YkRRaWlQYnRHWVQ0UTRLc0xuWTVKVStyVWh3L3lX?= =?utf-8?B?OVFpU2pRVjVQa3FDcTVWd3RtcmxGWmExaXBxTFV0elpEeVFIMWNaeGpPRnZ4?= =?utf-8?B?ZmhuS2RiZ0ZCUnRlQnhrdDZpMTVpTmliU0hsOThtUFQxVXR6Qmx1eDUvdTlW?= =?utf-8?B?aXpyWXlLOEExZGpvOXo0U0p0RG1sb1U5MEVLM0tDSGIyaGFFM1Z6Y1VXUEpW?= =?utf-8?B?ZXhCRzJ4TDNPZW0xWDhzRXhTc2FuOXM3RXNXbmNCRm9saFQvelZHazBBRTZU?= =?utf-8?B?OHpuZmt3VXFlV2pRUmFxTjYxZWR6Q2E5VzFIdUZ0U080U0NmblZzMEN5RExQ?= =?utf-8?B?UFRTUjROMlNhdXpGakVWNFY1SzIwa1gwNWVkM1hiWW9xOEgvYzBPS3pUYkxx?= =?utf-8?B?ZjVjTlFJRjlkVUM0M05ST3RQNGJqZjVGenM3VVFmeUVxSzJjaEdrSGh0NTdD?= =?utf-8?B?cndTQUxJUnQrMTVOYzhjK2hyN0ZlcDN3RFpzRVdNUldrdlhUY3NQRDVpRWoz?= =?utf-8?B?b0FXMStkOC9DTWNMaVliUE4vS0xmSHlRYzk1ZUpDL2dHRDR4dlFxYXErSklJ?= =?utf-8?B?TDE1T24rN0tmMTZ6TzlHbU1jQ3NWa2dRa0hmWGVDZmhpOU14dGZLN25TaGhm?= =?utf-8?B?OTdDbHVWWisvdkVFcXFhc3ZReTBUNElnSk9jTEhmeTZVSFFteGJDSmJuck56?= =?utf-8?B?bFFEckdvYktvdEszNTI0WkhXb3R1TGtmaVhQa3hCVG0yaXRxaW1hK1duQncr?= =?utf-8?B?MFpxN05ibG4zQ201ZlZ1eEhTZDVtOFFvNWRCMlBhcjlrMnlGY0dpakdwbkpW?= =?utf-8?B?VmtKYjI1Q0lNcW5FbU5MVDVWZUw2blRPN09pZEtTTnRiaHZiZDNiVWtKZGFi?= =?utf-8?B?U1lZa0dKZFR4TlRUSndodno2R0JxWEU4SEtINW92WVdCQ25CMk45cEV5aWNU?= =?utf-8?B?bk9kZThlaVNhRTdxeVFvK29LS2ZGcGt6Rks0QVlvaUFGUTBIZ20xdzdzeUFU?= =?utf-8?B?VW5jbVgycHVaZjUyREw3Nm0xUnRjOFBNWGR4aUp2SFM4WnpKUnFIWVJ0SHRL?= =?utf-8?B?YVdQOUZPUkRSczdKeVJOMVkzYjVobFpzMkJ6YitQbVI1d2YzZW5GcHlGS1NT?= =?utf-8?B?aDIxNHVVV0RDNHpSL2llZUU0SUlIYW5RQkYwN0t6ZlNxK0RPd0ZYcWptQkdI?= =?utf-8?B?OHl3dERrOTU1Z2FMVVFpUkE0bTVIbnZyOEFtL3YzRzVjek9RNG9qTXlkazRu?= =?utf-8?B?ZzRUVGxLdThIMUlFc0tnMUV5VTlNWGx6dXhkQk90ckZ1K0RXaytCV1htOHg4?= =?utf-8?B?akZ1VUt1VEpyaEVELzlvQi82bzk0Y1o3aDRDVUZJclFUaXlJT3cvYWg1OE5N?= =?utf-8?B?TlJyazdGY29HVG1jaSt5RlVXRFUvQTNZV0Vhb3o0WTFOZVRNbGVsMlBsMEhY?= =?utf-8?B?R1NpRmd0TWROcm5pVUJxbkZ6eTdWTzJiRmU0Um54RFh6bGRNUVI1NmZXVGNx?= =?utf-8?B?UHRnYmZPVjRQSFdRSXllUWhNU3VMYndLNzEwYzd2TGVUYWxYV0MzQ0VaSGFM?= =?utf-8?B?UW1YNGR3NDk5eS9XYjZqcDBVcDVhQ3hqNDBQT0I3Mnl1d3VaNFdQSGFTSUFS?= =?utf-8?B?QXlBRGhlcDQrWno4Z2NIZDNRbTd0djBhbGpjVEplQVdHOE1zVUMyekQ1Nisv?= =?utf-8?B?SU5BQ2MxbWorek9pNnpReUd4elpUL1IraGgxWHFjK2xqOU00V1paelQ4VmFF?= =?utf-8?B?LzFUZmJRc1h6bzc5N29yVk9aWUJzUW1XdDY4eXNOcVlkOEg4QlUrSzQyTkE4?= =?utf-8?Q?Ty3SxroCknIs4ks8eFF7555Yj?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: cce6c625-6ff5-4597-3e6c-08ddd40ab372 X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB7277.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Aug 2025 10:27:38.5295 (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: Wu1SGQE/hJ+ZfJBXXJk5GYVsXk8oJ4caEt+wzUbQj9BhyHaaK9SB160S5YbE1VNeu3rrRZDUhgc5ABoNUhNWfA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8789 On 8/5/25 14:24, Mika Penttilä wrote: > Hi, > > On 8/5/25 07:10, Balbir Singh wrote: >> On 8/5/25 09:26, Mika Penttilä wrote: >>> Hi, >>> >>> On 8/5/25 01:46, Balbir Singh wrote: >>>> On 8/2/25 22:13, Mika Penttilä wrote: >>>>> Hi, >>>>> >>>>> On 8/2/25 13:37, Balbir Singh wrote: >>>>>> FYI: >>>>>> >>>>>> I have the following patch on top of my series that seems to make it work >>>>>> without requiring the helper to split device private folios >>>>>> >>>>> I think this looks much better! >>>>> >>>> Thanks! >>>> >>>>>> Signed-off-by: Balbir Singh >>>>>> --- >>>>>> include/linux/huge_mm.h | 1 - >>>>>> lib/test_hmm.c | 11 +++++- >>>>>> mm/huge_memory.c | 76 ++++------------------------------------- >>>>>> mm/migrate_device.c | 51 +++++++++++++++++++++++++++ >>>>>> 4 files changed, 67 insertions(+), 72 deletions(-) >>>>>> >>>>>> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h >>>>>> index 19e7e3b7c2b7..52d8b435950b 100644 >>>>>> --- a/include/linux/huge_mm.h >>>>>> +++ b/include/linux/huge_mm.h >>>>>> @@ -343,7 +343,6 @@ unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long add >>>>>> vm_flags_t vm_flags); >>>>>> >>>>>> bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pins); >>>>>> -int split_device_private_folio(struct folio *folio); >>>>>> int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list, >>>>>> unsigned int new_order, bool unmapped); >>>>>> int min_order_for_split(struct folio *folio); >>>>>> diff --git a/lib/test_hmm.c b/lib/test_hmm.c >>>>>> index 341ae2af44ec..444477785882 100644 >>>>>> --- a/lib/test_hmm.c >>>>>> +++ b/lib/test_hmm.c >>>>>> @@ -1625,13 +1625,22 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf) >>>>>> * the mirror but here we use it to hold the page for the simulated >>>>>> * device memory and that page holds the pointer to the mirror. >>>>>> */ >>>>>> - rpage = vmf->page->zone_device_data; >>>>>> + rpage = folio_page(page_folio(vmf->page), 0)->zone_device_data; >>>>>> dmirror = rpage->zone_device_data; >>>>>> >>>>>> /* FIXME demonstrate how we can adjust migrate range */ >>>>>> order = folio_order(page_folio(vmf->page)); >>>>>> nr = 1 << order; >>>>>> >>>>>> + /* >>>>>> + * When folios are partially mapped, we can't rely on the folio >>>>>> + * order of vmf->page as the folio might not be fully split yet >>>>>> + */ >>>>>> + if (vmf->pte) { >>>>>> + order = 0; >>>>>> + nr = 1; >>>>>> + } >>>>>> + >>>>>> /* >>>>>> * Consider a per-cpu cache of src and dst pfns, but with >>>>>> * large number of cpus that might not scale well. >>>>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >>>>>> index 1fc1efa219c8..863393dec1f1 100644 >>>>>> --- a/mm/huge_memory.c >>>>>> +++ b/mm/huge_memory.c >>>>>> @@ -72,10 +72,6 @@ static unsigned long deferred_split_count(struct shrinker *shrink, >>>>>> struct shrink_control *sc); >>>>>> static unsigned long deferred_split_scan(struct shrinker *shrink, >>>>>> struct shrink_control *sc); >>>>>> -static int __split_unmapped_folio(struct folio *folio, int new_order, >>>>>> - struct page *split_at, struct xa_state *xas, >>>>>> - struct address_space *mapping, bool uniform_split); >>>>>> - >>>>>> static bool split_underused_thp = true; >>>>>> >>>>>> static atomic_t huge_zero_refcount; >>>>>> @@ -2924,51 +2920,6 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, >>>>>> pmd_populate(mm, pmd, pgtable); >>>>>> } >>>>>> >>>>>> -/** >>>>>> - * split_huge_device_private_folio - split a huge device private folio into >>>>>> - * smaller pages (of order 0), currently used by migrate_device logic to >>>>>> - * split folios for pages that are partially mapped >>>>>> - * >>>>>> - * @folio: the folio to split >>>>>> - * >>>>>> - * The caller has to hold the folio_lock and a reference via folio_get >>>>>> - */ >>>>>> -int split_device_private_folio(struct folio *folio) >>>>>> -{ >>>>>> - struct folio *end_folio = folio_next(folio); >>>>>> - struct folio *new_folio; >>>>>> - int ret = 0; >>>>>> - >>>>>> - /* >>>>>> - * Split the folio now. In the case of device >>>>>> - * private pages, this path is executed when >>>>>> - * the pmd is split and since freeze is not true >>>>>> - * it is likely the folio will be deferred_split. >>>>>> - * >>>>>> - * With device private pages, deferred splits of >>>>>> - * folios should be handled here to prevent partial >>>>>> - * unmaps from causing issues later on in migration >>>>>> - * and fault handling flows. >>>>>> - */ >>>>>> - folio_ref_freeze(folio, 1 + folio_expected_ref_count(folio)); >>>>>> - ret = __split_unmapped_folio(folio, 0, &folio->page, NULL, NULL, true); >>>>>> - VM_WARN_ON(ret); >>>>>> - for (new_folio = folio_next(folio); new_folio != end_folio; >>>>>> - new_folio = folio_next(new_folio)) { >>>>>> - zone_device_private_split_cb(folio, new_folio); >>>>>> - folio_ref_unfreeze(new_folio, 1 + folio_expected_ref_count( >>>>>> - new_folio)); >>>>>> - } >>>>>> - >>>>>> - /* >>>>>> - * Mark the end of the folio split for device private THP >>>>>> - * split >>>>>> - */ >>>>>> - zone_device_private_split_cb(folio, NULL); >>>>>> - folio_ref_unfreeze(folio, 1 + folio_expected_ref_count(folio)); >>>>>> - return ret; >>>>>> -} >>>>>> - >>>>>> static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, >>>>>> unsigned long haddr, bool freeze) >>>>>> { >>>>>> @@ -3064,30 +3015,15 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, >>>>>> freeze = false; >>>>>> if (!freeze) { >>>>>> rmap_t rmap_flags = RMAP_NONE; >>>>>> - unsigned long addr = haddr; >>>>>> - struct folio *new_folio; >>>>>> - struct folio *end_folio = folio_next(folio); >>>>>> >>>>>> if (anon_exclusive) >>>>>> rmap_flags |= RMAP_EXCLUSIVE; >>>>>> >>>>>> - folio_lock(folio); >>>>>> - folio_get(folio); >>>>>> - >>>>>> - split_device_private_folio(folio); >>>>>> - >>>>>> - for (new_folio = folio_next(folio); >>>>>> - new_folio != end_folio; >>>>>> - new_folio = folio_next(new_folio)) { >>>>>> - addr += PAGE_SIZE; >>>>>> - folio_unlock(new_folio); >>>>>> - folio_add_anon_rmap_ptes(new_folio, >>>>>> - &new_folio->page, 1, >>>>>> - vma, addr, rmap_flags); >>>>>> - } >>>>>> - folio_unlock(folio); >>>>>> - folio_add_anon_rmap_ptes(folio, &folio->page, >>>>>> - 1, vma, haddr, rmap_flags); >>>>>> + folio_ref_add(folio, HPAGE_PMD_NR - 1); >>>>>> + if (anon_exclusive) >>>>>> + rmap_flags |= RMAP_EXCLUSIVE; >>>>>> + folio_add_anon_rmap_ptes(folio, page, HPAGE_PMD_NR, >>>>>> + vma, haddr, rmap_flags); >>>>>> } >>>>>> } >>>>>> >>>>>> @@ -4065,7 +4001,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, >>>>>> if (nr_shmem_dropped) >>>>>> shmem_uncharge(mapping->host, nr_shmem_dropped); >>>>>> >>>>>> - if (!ret && is_anon) >>>>>> + if (!ret && is_anon && !folio_is_device_private(folio)) >>>>>> remap_flags = RMP_USE_SHARED_ZEROPAGE; >>>>>> >>>>>> remap_page(folio, 1 << order, remap_flags); >>>>>> diff --git a/mm/migrate_device.c b/mm/migrate_device.c >>>>>> index 49962ea19109..4264c0290d08 100644 >>>>>> --- a/mm/migrate_device.c >>>>>> +++ b/mm/migrate_device.c >>>>>> @@ -248,6 +248,8 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, >>>>>> * page table entry. Other special swap entries are not >>>>>> * migratable, and we ignore regular swapped page. >>>>>> */ >>>>>> + struct folio *folio; >>>>>> + >>>>>> entry = pte_to_swp_entry(pte); >>>>>> if (!is_device_private_entry(entry)) >>>>>> goto next; >>>>>> @@ -259,6 +261,55 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, >>>>>> pgmap->owner != migrate->pgmap_owner) >>>>>> goto next; >>>>>> >>>>>> + folio = page_folio(page); >>>>>> + if (folio_test_large(folio)) { >>>>>> + struct folio *new_folio; >>>>>> + struct folio *new_fault_folio; >>>>>> + >>>>>> + /* >>>>>> + * The reason for finding pmd present with a >>>>>> + * device private pte and a large folio for the >>>>>> + * pte is partial unmaps. Split the folio now >>>>>> + * for the migration to be handled correctly >>>>>> + */ >>>>>> + pte_unmap_unlock(ptep, ptl); >>>>>> + >>>>>> + folio_get(folio); >>>>>> + if (folio != fault_folio) >>>>>> + folio_lock(folio); >>>>>> + if (split_folio(folio)) { >>>>>> + if (folio != fault_folio) >>>>>> + folio_unlock(folio); >>>>>> + ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); >>>>>> + goto next; >>>>>> + } >>>>>> + >>>>> The nouveau migrate_to_ram handler needs adjustment also if split happens. >>>>> >>>> test_hmm needs adjustment because of the way the backup folios are setup. >>> nouveau should check the folio order after the possible split happens. >>> >> You mean the folio_split callback? > > no, nouveau_dmem_migrate_to_ram(): > .. > sfolio = page_folio(vmf->page); > order = folio_order(sfolio); > ... > migrate_vma_setup() > .. > if sfolio is split order still reflects the pre-split order > Will fix, good catch! >> >>>>>> + /* >>>>>> + * After the split, get back the extra reference >>>>>> + * on the fault_page, this reference is checked during >>>>>> + * folio_migrate_mapping() >>>>>> + */ >>>>>> + if (migrate->fault_page) { >>>>>> + new_fault_folio = page_folio(migrate->fault_page); >>>>>> + folio_get(new_fault_folio); >>>>>> + } >>>>>> + >>>>>> + new_folio = page_folio(page); >>>>>> + pfn = page_to_pfn(page); >>>>>> + >>>>>> + /* >>>>>> + * Ensure the lock is held on the correct >>>>>> + * folio after the split >>>>>> + */ >>>>>> + if (folio != new_folio) { >>>>>> + folio_unlock(folio); >>>>>> + folio_lock(new_folio); >>>>>> + } >>>>> Maybe careful not to unlock fault_page ? >>>>> >>>> split_page will unlock everything but the original folio, the code takes the lock >>>> on the folio corresponding to the new folio >>> I mean do_swap_page() unlocks folio of fault_page and expects it to remain locked. >>> >> Not sure I follow what you're trying to elaborate on here > > do_swap_page: > .. > if (trylock_page(vmf->page)) { > ret = pgmap->ops->migrate_to_ram(vmf); > <- vmf->page should be locked here even after split > unlock_page(vmf->page); > Yep, the split will unlock all tail folios, leaving the just head folio locked and this the change, the lock we need to hold is the folio lock associated with fault_page, pte entry and not unlock when the cause is a fault. The code seems to do the right thing there, let me double check Balbir and the code does the right thing there.