From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7C88ECAC5AE for ; Wed, 24 Sep 2025 04:47:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 678788E0002; Wed, 24 Sep 2025 00:47:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6501C8E0001; Wed, 24 Sep 2025 00:47:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 518058E0002; Wed, 24 Sep 2025 00:47:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 3C2B18E0001 for ; Wed, 24 Sep 2025 00:47:21 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id AE17C16053A for ; Wed, 24 Sep 2025 04:47:20 +0000 (UTC) X-FDA: 83922909840.30.1D9EFFD Received: from SN4PR2101CU001.outbound.protection.outlook.com (mail-southcentralusazon11012045.outbound.protection.outlook.com [40.93.195.45]) by imf15.hostedemail.com (Postfix) with ESMTP id CEC63A0006 for ; Wed, 24 Sep 2025 04:47:17 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="XlYn/6p1"; spf=pass (imf15.hostedemail.com: domain of balbirs@nvidia.com designates 40.93.195.45 as permitted sender) smtp.mailfrom=balbirs@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758689238; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=KtHeR46Nk3rLewehA/RV+8YXkP4kaM1mgLzKlIgekOE=; b=rtQP1ML0sTSabm4pkyx4+awt2UIZGMY4NXeLXBspFawqFCLeHE7nVdBOZR7nRd4gy9lbg1 msNVHJMbrEQpntuyRk6yMbw0snwYSwHkCEUmDxpzL2dejV4ag3XTo3sWCOEdOLnkRQN6dA cclrUAtBNSoB1VQINFpqDbmUa14yhHQ= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1758689238; a=rsa-sha256; cv=pass; b=ZecFsNlCYcS2iy+1ReapJGO1cbuwuVai3SX8N8sBpZ/tHnjk5YyGyFldbyZDdV6dldxGsO T7YOhkbnpBAENDL3oL9TdSJOuoPAW0YiDdZiJ0TII683Nr2K55jATTQ4II2AKV32nH6L0t KsSjyTOdhT3b/FlGdryAxu0cdTeppGY= ARC-Authentication-Results: i=2; imf15.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="XlYn/6p1"; spf=pass (imf15.hostedemail.com: domain of balbirs@nvidia.com designates 40.93.195.45 as permitted sender) smtp.mailfrom=balbirs@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=nvidia.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=hXKe0wRtdSkzr+gslGZghpp6r7wbfk1jVhaiUukS0A+p8jTHZGMQiAGEIvJvLbrUcHxMYbY2/sAyrN4OlJNdjyyD7eqwDLuvHnKCS7MdiE/pVjk0qdGh437yW1iKZ+M/ZKWDYghOZuQrF42XVpO57YUhqTMNPr9M/kObDVrterBU+8NMqsv22/DnGrBXKlTybEAlmOWwtg185+z3TtBpSfDB0nH5l8SUr8FMgI25PqgiVdiXvZOsyAc1mbLRLWFabaNvOMs96WDmBttZLle7w7CR9ioq5N0KExMfYqNuaV8Yxf17JpUjI1QJd2Ihp8Dsl6Xh2iKQ93Zr4coOjpLGpg== 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=KtHeR46Nk3rLewehA/RV+8YXkP4kaM1mgLzKlIgekOE=; b=mcV0rnnyHfGIQxGxA9mCxf++B94ZUQ2GoereJCa8NPc342gNOD1szxf+vcN/ufJ3i3z5gkSFZc8XIYPrwFA1qtBDRjabrIFXQ2KGLyjY0U55BwVCQzqYgev9LOW904bUplOsGWQhwHhoFgRwnvExna6JUW3ogvJZML9rUHwUIMq3OP7L5Gj0YPsaeZ5dJAa29nwut4WHYhr5jN25No8hgWQZkVr8z/vuYomrvO2dKsiUUtIeXQ43bXK92LsHkmdhhTAODlg2yjqoPsh9LKTOAj5XOCUTugyK3IH1SiAX52uXixjBRd+2Pl2kDYVROETFhW3hLkNpWH1LwMoDjQFe2Q== 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=KtHeR46Nk3rLewehA/RV+8YXkP4kaM1mgLzKlIgekOE=; b=XlYn/6p1OrAsnl/xD4wcYCRLo8JF8U3s2WYPuACPfrrBxnwDffHRrc1jog9R1HDM5rDHTfg9kZISwnpdd+skSR8BU0h/g09QcHbo9dT/93WiTxpZfQXfgo/2WtChyPpKIUXIaJqbXnYyN0Kdpg99i4OSUXpAmERf22macBuGmwFfW90qDEq41pzaq3gNM7BQogARceciuNBaOia5xeZYyYX9fYHE1jiyexWl0ez8e2ue04rst0pk2Col0+NCMRGCEPySN/1fekjSfee2rk0/Wj8QRcL4Ymr/pSTXB9ter+iJbwJeM3Kq57fb9oKx71n5Di2YSO/dq9efyhH8eOrQ1w== Received: from PH8PR12MB7277.namprd12.prod.outlook.com (2603:10b6:510:223::13) by MW4PR12MB7237.namprd12.prod.outlook.com (2603:10b6:303:22a::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.20; Wed, 24 Sep 2025 04:47:13 +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 15.20.9160.008; Wed, 24 Sep 2025 04:47:13 +0000 Message-ID: <64d0b302-55c5-45bb-8aa5-d00d25d8d07e@nvidia.com> Date: Wed, 24 Sep 2025 14:47:06 +1000 User-Agent: Mozilla Thunderbird Subject: Re: [v6 05/15] mm/migrate_device: handle partially mapped folios during collection To: Karim Manaouil Cc: Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, damon@lists.linux.dev, dri-devel@lists.freedesktop.org, David Hildenbrand , 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_Penttil=C3=A4?= , Matthew Brost , Francois Dugast References: <20250916122128.2098535-1-balbirs@nvidia.com> <20250916122128.2098535-6-balbirs@nvidia.com> <3FE3F2B9-86F9-4EED-863A-093FE3959B1A@nvidia.com> <62fb7aca-cd30-4058-bfd1-d08f78d5c38d@nvidia.com> <20250923155640.lbtvyi54ueyv2tjb@wrangler> Content-Language: en-US From: Balbir Singh In-Reply-To: <20250923155640.lbtvyi54ueyv2tjb@wrangler> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: BYAPR02CA0035.namprd02.prod.outlook.com (2603:10b6:a02:ee::48) To PH8PR12MB7277.namprd12.prod.outlook.com (2603:10b6:510:223::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR12MB7277:EE_|MW4PR12MB7237:EE_ X-MS-Office365-Filtering-Correlation-Id: bbbb9f92-a019-4aa4-a73d-08ddfb256e0b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|10070799003; X-Microsoft-Antispam-Message-Info: =?utf-8?B?RXR2WmRPNVY1OXFtZFlEdnlJQlZ2Uzlhc0oxODQvY25QQWs2ZnlzSmxkeEps?= =?utf-8?B?eERNNVVzVkV4bkxyNXAxMGFpNWJnR2RNdFZsZG5xTWFaREJMZFBtc01Rdms2?= =?utf-8?B?dFVFWGh3MzJvelp2eno2YmlXMWhXTnJ2Njd3NkZ6QkNxSDA3ZmpTblpjMEZ1?= =?utf-8?B?OWF6VEk1clh0dHkyZ2hCQlJHdHByRldGL2JZUmZzSTRlT3lLbEFYVGY2a1Iy?= =?utf-8?B?MlpxRUYzZ1VzVDBPTCtsL3cvdDVKcUVISUdSbXpBZkJWNFNUdnE2bHM1eGFK?= =?utf-8?B?dkkxNzd4OTNaYnlVWnRoWFZxVm9qcjZVWWFoMk1PMnlmQzRlU0VZeVRsN1Ni?= =?utf-8?B?R252c2RUS056SjMza0R3NERJRHZPOUV4MUViQUp0VTg5Z1BaKy9kelJwZmlK?= =?utf-8?B?SEVKOGJqeUxaeGlveGE4clMrK1poTGtwalNzYkQ1TjZPc2hRZzJ3QnVZUUV4?= =?utf-8?B?Zlh4Z1h1Y2lmN3NyZU9kelV4dC9RWkhlRWoxcTJpM2pJTCthWGNrdi9Pak9j?= =?utf-8?B?UUhYYVJtcStobWF1VVk2NzRzajdTMmhieEpjYk1wU3d4NWlzQlNsYWtiTktu?= =?utf-8?B?NXpYTGZwWXV3REVaMHNQWFZvZ1FnM3NxUkhITEpWRis0VnJheERZTTcwZnpu?= =?utf-8?B?NEdtM0k4Q1RsbmdkSjU3eGFXVmNKV3VFenhqUkVZYnF5OUQ1YjRTcUFic0I0?= =?utf-8?B?MGs5NlN3cFlpRnBpY20yZUVHSlV6N09INEs1cTVvMGhCWDI3RVp6WHdzcXpK?= =?utf-8?B?UjNOeHJ4TkJnaW1ENVRXNWNRbVBoZVJwTjFVdmU0Z2k0Q2NFalphM1M5K25y?= =?utf-8?B?V09ESG95d1NDOW53OHNMZmkzclY0WmFxQ3VPRi9KejBYbWZwbjFxcjZoMkNI?= =?utf-8?B?MVBXbFF5eGlZZGliNkd1a2t2aHI0bnNkUjV4N0Q3RVRnaER1Sk9JUkFTekVZ?= =?utf-8?B?T0NnanJlUWp5RmZyRkhOaVR4SlMrM3BEai9BeVZVS2VwZ2xZT3NoeU1vbWFs?= =?utf-8?B?QUI5d3RHV2V1UDVmcWdmR3hqSUQyWVp2YVJybHNJeThicCs2aVhlb1UveWt6?= =?utf-8?B?MnlMRjFSQytPRk1YRlhUdHRKaWMwa2UyUnp6OFlsc3ZMY3Z0RzZuWlV1Y2RL?= =?utf-8?B?WGZObVUybUliR0tRSzJNZDBkeXVYK054OGRSUHgvVXR5Y3cvUHh1WjhnUnVM?= =?utf-8?B?cCtETy9GcFpjOC9MUWFBVEVKS29HK0VMRXlRVkpPYm1GT2o3VUlHdSsySGNZ?= =?utf-8?B?SDdLdHJMRUhTZVJlL1hHRjNZT1IrNm5WTk1aQVZyYytoREZhdEZQOG5tWHBl?= =?utf-8?B?VTFHUkZwY1VTdmhoTXF2RjZoUVc5WUtZbFdPWE5ETktTc2YvZ2M3RkNUb2l0?= =?utf-8?B?WmxqL3k0SHBYdzQ3MFU2SVFJVkJlQ3BmUERvdUltV29lSmVZbVhNeFY5MytZ?= =?utf-8?B?RXh6L2phMG9waXkyZzlUeWdhdXZ5OVBMekRtM3NwRjUzOGlFR2ZrS01COW42?= =?utf-8?B?YXhnOGVDZnRtZnJsRi9vdlFiVGF5ekswR1lTOW1DRVJlRk05Y0d5RHZSUzJq?= =?utf-8?B?RnRZNHRqdWg4WHJQRTlCbmVoZzE1ODN6VzdrVjhqOVZZYW84Rno1U3pEcFlP?= =?utf-8?B?NmFYeENZYnQyT2ZsdDZGM3VGRWlRaGllODhMbU5ja2krM09BN2hydkVqcTNo?= =?utf-8?B?Z3F2ZmlaakhtVHZaUnhUanRkRjc5MTk4aGE0Z0RkTXh6cy9ZZnl4cEN2RTZs?= =?utf-8?B?dVI2dDFoOEJMRlEvNXhwWkF5OUJoMVhkK1BSR2UwVGxQdk9JR3RBRFFpd1p1?= =?utf-8?B?MnVFSExZUXFDbXUySGlUd2ZIM2J5b3dZMkdNR3dSNzhEUW5USWRrMGhBc3V1?= =?utf-8?B?Q1J2TDlFZU5UWjhrK2VaeGtIZG5Xa1JZM3lGRzNYdFZWNFZZODhuOExSaTYw?= =?utf-8?Q?cg5kKfzgg+M=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)(376014)(7416014)(1800799024)(10070799003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZHRWbHhQVTNLQi8xeWlLTHkzRUYzTGk4MzdnMnRPZGlWdTRxaHVCQjFNRmsr?= =?utf-8?B?b1F1SVpzd283VTRBZFlyeC9ma01rWVVwNjNiVU1ERGV3WGM5cC9RanFiMjVv?= =?utf-8?B?ZFRHSytnaWFvY1hYMFFnbHFiclEvUFpzcEZPZzdiaThLdng5UU1sM3NScWxP?= =?utf-8?B?SkJjYTBrZ0hqZ1ZRd2NHNGpxbmdiVlY2Z05adllXN1lraTBqaFFiV0REY1Rj?= =?utf-8?B?UDdJVE9Yam4xNVNZaDY4bkE4NE5GcDU4eHJWakcwZHlUVnExSlF1TGphdzJy?= =?utf-8?B?RnlRbGdxcUlEZ3ZISHprNG5KUU91alBubjBqc1dWbmV6d1J4Y2NVT3duZzc2?= =?utf-8?B?ak41d0h1cm9MMGFTbVljeHRYb2ZRbXBNRFBrc3BteSt6YUdwYm0vbWdoVWlB?= =?utf-8?B?VkVDVFFuK3hFR3NEVENtUmNERzVTMklhQjdTakpZNDhadmVzeGpSbDlqb1hj?= =?utf-8?B?V21jMHFaaExURVMvSzJmbGZya1RBM0pEMldvQXpPaE1TTG9KR3B2dHdRd2VM?= =?utf-8?B?NVJnRjAra0E2VGlIWW16a0ZCQzI0b1lZOCtlMnA0SllSYU9Ba0hWOWNHKytt?= =?utf-8?B?eDh6MG1zbFUrczFGdGpsWnVKeEtQN3pvL3Z5em5INElHc1dYMWNTaDZIM0tB?= =?utf-8?B?c2lQai9uanNhYnN2NkRESnVya21CSVMvRmJoY0JJUGlHVmU3TXRQbnVWbnFw?= =?utf-8?B?aVVvL1cyNnNVc0ptSjA2ZEF4RU9UUHhiLzRBZTE0bFJvWm1SMDR2blUyS2Np?= =?utf-8?B?QU5SMVNuYktEN2JuVHR2WTBXSjJGbWFCUlR1NTd4TDU2QUgwTHhwL1IwZFFC?= =?utf-8?B?RTU2cWtWSUNpZldHZWthaW52bDVnNGR6L2ova21Jc1g2MGY4WWFUWFBRTlBa?= =?utf-8?B?ZDNWTDM3UExmUWkwQ0JuU2ZBcVhSZEY1Y0QvUUZjR0IrNGZhT0NKUk9rSDZO?= =?utf-8?B?Z1pxWldyUlZtT0tYeEIybVJUWWVONDFtbHlhKzh5bzFNZFVoQUVyN1lXTzBQ?= =?utf-8?B?SVU2bDhweXRnaENDalVDYVdkZm5xY2VQblBlWFZuaGpmZFhMYU9WVmNpaFVy?= =?utf-8?B?anFlQlhieHIxNzA0Y3RvTzFKY0VweWN5NUpJaU4wK0pRbXEvMDRBaksyV1hP?= =?utf-8?B?T0U3bEQ1dXNvS0hubEd1TEx1RDVKVkZueXJzcDVqWnNUZ3g4RytJN09WeWsw?= =?utf-8?B?ZUhML0h0WXdpbWJIay8wN0dON01ES3RvbUpTQWt3WUQ4bjJXaDVXRCtjNU1S?= =?utf-8?B?eGNYeFBzclJLSFkyNmlsL0hKdEVqQS9FN3B0L3ZYZS8wU3ZFeGoxS1hhUm5y?= =?utf-8?B?ZmRXRzg0bDhQcmZyRGFsbUNmc244TzJJbC84dWJYYTFMQUVlSG80UlRpOHVL?= =?utf-8?B?Z0hwQXhYdlcwYUt6SW1NUG1qMmhCSDdTWkR0MHQwWEpTS1h4d3k0eFhPV3hi?= =?utf-8?B?KzhRNzRwVnkrTU9QaUl2K0RBOXRZZ0s3OHY3K2M1ZDN3RkM4c2tVdFNUVldH?= =?utf-8?B?dnozalZXRTVkV0FteGdiNFN5SmxGQXBqR2d5d3p2bWZnLytjc0JhaW5oRElt?= =?utf-8?B?UHNSWHpROFZFRDVjWHpXZUJGNkh6TE8rTE9UYW5DbnVXNTN2a3F0QVFrNEdH?= =?utf-8?B?dnk4eGphYWdPQ0hIRjhDcXhCdStZWm1CT2JYd2pvdzVjS1lNVlU3TDc1YWNF?= =?utf-8?B?SllWSTRFdFZ0eTFtb1JURmhnd3M0d2lxamtaZk54YzNkTzZpem9UNjBxbHdt?= =?utf-8?B?YUNTc2I4T01KbzA4U3NyZXF2KzZPUXp1ZExyR3JQUVRxeFhUUjFCZGhMWlZh?= =?utf-8?B?T0hvZXhKR1Zqam9ZbnJuY041bnZQOEZqYUxzYTFuaVFUZkRIUWhYcHp5dEhm?= =?utf-8?B?WjQwWU5ERlpDVUFXamNqTlRuazFqWmcvdlFIVEpROStqUC83dVhkRE9ERGNS?= =?utf-8?B?YjBNUE1hT0hDZEhPdFA1QVR4YVRveWYwSFYvMFhINFZiU2FxeEx1VGdmNFhV?= =?utf-8?B?cmNkSXF4T3Z3M2lCZS9tdk1XblRnRnFSbHpFZkJCenFMSFdmZks2T0pkWWVW?= =?utf-8?B?RUhGdnVzejBvZk5ZaHFNVzBFelNnRkg1Tk1aTWNHa2F5SlhERzl5TTNKcG5Z?= =?utf-8?B?dVdWa0pOckcxdmFsbnFZZHlGalczWTVjVUlpQU1TNXo3WDZSVllMTTRLUjVG?= =?utf-8?Q?BzCwqulmLOAIWYqXiSNWixBxVZ1os1PSCz4vFn4vKnYR?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: bbbb9f92-a019-4aa4-a73d-08ddfb256e0b X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB7277.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Sep 2025 04:47:13.7712 (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: r5SU7NQP0pfp75wvS44t6+mBJeLXMug7VIKZkFEbWir5rku6ClSUfRwL3iwiWkwOSF7OKp+wcJXcmXsNlH/q9Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB7237 X-Rspamd-Queue-Id: CEC63A0006 X-Stat-Signature: gy7z31zmayh5gr11ogm6zrwq41rgy94h X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1758689237-232146 X-HE-Meta: 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 AzdS/CFx 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 38Rq55dr X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/24/25 01:56, Karim Manaouil wrote: > On Tue, Sep 23, 2025 at 01:44:20PM +1000, Balbir Singh wrote: >> On 9/23/25 12:23, Zi Yan wrote: >>> On 16 Sep 2025, at 8:21, Balbir Singh wrote: >>> >>>> Extend migrate_vma_collect_pmd() to handle partially mapped large folios >>>> that require splitting before migration can proceed. >>>> >>>> During PTE walk in the collection phase, if a large folio is only >>>> partially mapped in the migration range, it must be split to ensure the >>>> folio is correctly migrated. >>>> >>>> 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 Penttilä >>>> Cc: Matthew Brost >>>> Cc: Francois Dugast >>>> --- >>>> mm/migrate_device.c | 82 +++++++++++++++++++++++++++++++++++++++++++++ >>>> 1 file changed, 82 insertions(+) >>>> >>>> diff --git a/mm/migrate_device.c b/mm/migrate_device.c >>>> index abd9f6850db6..70c0601f70ea 100644 >>>> --- a/mm/migrate_device.c >>>> +++ b/mm/migrate_device.c >>>> @@ -54,6 +54,53 @@ static int migrate_vma_collect_hole(unsigned long start, >>>> return 0; >>>> } >>>> >>>> +/** >>>> + * migrate_vma_split_folio() - Helper function to split a THP folio >>>> + * @folio: the folio to split >>>> + * @fault_page: struct page associated with the fault if any >>>> + * >>>> + * Returns 0 on success >>>> + */ >>>> +static int migrate_vma_split_folio(struct folio *folio, >>>> + struct page *fault_page) >>>> +{ >>>> + int ret; >>>> + struct folio *fault_folio = fault_page ? page_folio(fault_page) : NULL; >>>> + struct folio *new_fault_folio = NULL; >>>> + >>>> + if (folio != fault_folio) { >>>> + folio_get(folio); >>>> + folio_lock(folio); >>>> + } >>>> + >>>> + ret = split_folio(folio); >>>> + if (ret) { >>>> + if (folio != fault_folio) { >>>> + folio_unlock(folio); >>>> + folio_put(folio); >>>> + } >>>> + return ret; >>>> + } >>>> + >>>> + new_fault_folio = fault_page ? page_folio(fault_page) : NULL; >>>> + >>>> + /* >>>> + * Ensure the lock is held on the correct >>>> + * folio after the split >>>> + */ >>>> + if (!new_fault_folio) { >>>> + folio_unlock(folio); >>>> + folio_put(folio); >>>> + } else if (folio != new_fault_folio) { >>>> + folio_get(new_fault_folio); >>>> + folio_lock(new_fault_folio); >>>> + folio_unlock(folio); >>>> + folio_put(folio); >>>> + } >>>> + >>>> + return 0; >>>> +} >>>> + >>>> static int migrate_vma_collect_pmd(pmd_t *pmdp, >>>> unsigned long start, >>>> unsigned long end, >>>> @@ -136,6 +183,8 @@ 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; >>>> @@ -147,6 +196,23 @@ 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)) { >>>> + int ret; >>>> + >>>> + pte_unmap_unlock(ptep, ptl); >>>> + ret = migrate_vma_split_folio(folio, >>>> + migrate->fault_page); >>>> + >>>> + if (ret) { >>>> + ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); >>>> + goto next; >>>> + } >>>> + >>>> + addr = start; >>>> + goto again; >>>> + } >>> >>> This does not look right to me. >>> >>> The folio here is device private, but migrate_vma_split_folio() >>> calls split_folio(), which cannot handle device private folios yet. >>> Your change to split_folio() is in Patch 10 and should be moved >>> before this patch. >>> >> >> Patch 10 is to split the folio in the middle of migration (when we have >> converted the entries to migration entries). This patch relies on the >> changes in patch 4. I agree the names are confusing, I'll reword the >> functions > > Hi Balbir, > > I am still reviewing the patches, but I think I agree with Zi here. > > split_folio() will replace the PMD mappings of the huge folio with PTE > mappings, but will also split the folio into smaller folios. The former > is ok with this patch, but the latter is probably not correct if the folio > is a zone device folio. The driver needs to know about the change, as > usually the driver will have some sort of mapping between GPU physical > memory chunks and their corresponding zone device pages. > Yes, at this point there is no support for split folio callback. I can move this bit to a later patch or move the entire patch to after patch 10. I suspect this is a theoretical bisection concern for a future driver using large folios? Thanks, Balbir