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 BE560C982E4 for ; Fri, 16 Jan 2026 17:50:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2004B6B0088; Fri, 16 Jan 2026 12:50:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1D1486B0089; Fri, 16 Jan 2026 12:50:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0827A6B008A; Fri, 16 Jan 2026 12:50:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id EEEE06B0088 for ; Fri, 16 Jan 2026 12:50:02 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id A5E80B6E21 for ; Fri, 16 Jan 2026 17:50:02 +0000 (UTC) X-FDA: 84338565444.05.6AC50FB Received: from CH4PR04CU002.outbound.protection.outlook.com (mail-northcentralusazon11013058.outbound.protection.outlook.com [40.107.201.58]) by imf03.hostedemail.com (Postfix) with ESMTP id DC7182000D for ; Fri, 16 Jan 2026 17:49:59 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=nEfKSAGh; spf=pass (imf03.hostedemail.com: domain of jgg@nvidia.com designates 40.107.201.58 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1768585800; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=xV2Cx+sqaAFPfOgs8dhgf6nRx9XJJ78GMLl+Q/s9ygs=; b=jgrdFmtGP+RgnQ9RkqfF+lg2ekjHg1eRfNAua1W5BPMZa9xCzuMsyPz7PaGqwLZ+WQPTGQ jXZ6G5EuUju7T91fdDji72z+dJp9pklbFR86RJ+F0gtRTMQK9Zz/y53pgtsZpGbWDhcNuC cgEi/t2Oke1XTp7dQ7at+VeHOA6ci/Y= ARC-Authentication-Results: i=2; imf03.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=nEfKSAGh; spf=pass (imf03.hostedemail.com: domain of jgg@nvidia.com designates 40.107.201.58 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1768585800; a=rsa-sha256; cv=pass; b=kAL7J36qEzJQuhFhUAhGzW6IBeHV/UcXsLms7+LOH3uY68dGunc0WSIY3xIGHNt8KsBfzy N34mq1IW+06bd6Y3I+eLx4CSIrLZrGVC70M1evrolFcrjmg3oudrmLJ0ebDygi6c2FidYu aB5dsoUpvVFLGGku0c8YP1Bz3L90dIk= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=rhhkydaSPeSxydHfYpVP02AyimjGfehCZMkKfkxIXew61MAcUk7pPqaPVpRMGHELd+8HNlDqRPfLOO7axqArBx3drr8rV9iBm2hhEM+Mj+eKw2Er8utuX4LAayYIxKl3qvFuD8g5UnOqt26fvujtRTGMkrLyIOwEejS16T0MbYPhToUwcvircnECv8c26BRqyCsVhbQiQ6wHPiBFm3bimQxB9oiJV63lGDB82zgfg+W7rcP8SxqL/n01tRQPZ72WkjqzMFBDAKnz5d53WJjx7wOC3cD30IGhp8QOM57ouatrwqo16v7KwqN4qzrJjS8hQQLOfNfA4+r70zUwoLosJw== 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=xV2Cx+sqaAFPfOgs8dhgf6nRx9XJJ78GMLl+Q/s9ygs=; b=BIAb+OlRn+JHC1vlVhanDRZIQ2ilLaqU6Bvd+JnA4bfPoakLbd98PydCmQkjhiDtF+OkDjNgNZv97xJmc8DZLFCuRxzz9g+q/LvTvu+rPQh/7HZvJeyeKsL9pfd+Tp3rUipMsUyZHc75uc2KduhsUMj6nvCEewn/4IvCyulDFzQBAA0P2Cw2zdzVaVGiwXPfeJ1d36pj5hPYzpGHLMUttOmbHBAeDknUI95D1zueRvSqHMbaWUeTW9/0oQ81SGRoqYtfemPbsbGEyWOvB8Gw9kEPPlOgyVQXUKTuIcuaIMGw3f0xn8bn2s9ULX7xbg2BIn/PJabfq9gSceWM4V8+XQ== 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=xV2Cx+sqaAFPfOgs8dhgf6nRx9XJJ78GMLl+Q/s9ygs=; b=nEfKSAGhj+o/7qfKCV1DNQ4VBlBcTRUxoJeC0KLfxvqMS47OeInkAUWRRV3ITyTLlG3meHyZO80NJGTwKc2DtmzbZG8FAqcd9os8b+aiyFJQiNWERKcgRearPEJq6xRJ6p6I3vW7elIxsdGudU01OkK33bx2uYXQmy69fXdpCATTpZue2kz7tSI5ky1hw1ileZVb1nh0g8qE5HhIIO0sNCh6A/m5LiXeBkLa+FxVhFLXKNRWFoltwGPYhjOhmADN/QtVERCgaQKgeZYUAntF+ccy3WPkEgVxaRoVsn+PJkYfdHoMGiDSjjxHRzn4rSjX+OMlfFkMzGOsPApsvEuEMw== Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by CY3PR12MB9605.namprd12.prod.outlook.com (2603:10b6:930:103::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9520.5; Fri, 16 Jan 2026 17:49:48 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::1b59:c8a2:4c00:8a2c]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::1b59:c8a2:4c00:8a2c%3]) with mapi id 15.20.9520.005; Fri, 16 Jan 2026 17:49:48 +0000 Date: Fri, 16 Jan 2026 13:49:47 -0400 From: Jason Gunthorpe To: Francois Dugast Cc: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Matthew Brost , Zi Yan , Alistair Popple , adhavan Srinivasan , Nicholas Piggin , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Felix Kuehling , Alex Deucher , Christian =?utf-8?B?S8O2bmln?= , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Lyude Paul , Danilo Krummrich , David Hildenbrand , Oscar Salvador , Andrew Morton , Leon Romanovsky , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Balbir Singh , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org Subject: Re: [PATCH v6 1/5] mm/zone_device: Reinitialize large zone device private folios Message-ID: <20260116174947.GA1134434@nvidia.com> References: <20260116111325.1736137-1-francois.dugast@intel.com> <20260116111325.1736137-2-francois.dugast@intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260116111325.1736137-2-francois.dugast@intel.com> X-ClientProxiedBy: BLAP220CA0023.NAMP220.PROD.OUTLOOK.COM (2603:10b6:208:32c::28) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|CY3PR12MB9605:EE_ X-MS-Office365-Filtering-Correlation-Id: 308b4c01-ef95-4192-f891-08de5527a468 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|366016|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?ddD/1EYCzj+9fHThuWnm49SEIkIGMO7M38xpnx8V6Pw2ElWJAL8H8GQh8WdS?= =?us-ascii?Q?/aPcE7RLQuYMIMO2EuGL/YdcripJJWq4eE5eIuRqGfWX8eNKu2sfcT9OBUOs?= =?us-ascii?Q?isTM9DIxtIAiosSIK/R8HbdOA5EK6VGrZhSNsP2rlm4mAy+2gGvnIzo/mB7A?= =?us-ascii?Q?DWsmp0LxCXKQHivEvjhh6BjVGMuWhdm7M5Z+/XUscA0kEj1/p+IYlSBLCUfJ?= =?us-ascii?Q?+nd1roKHDh3SrpLhSg4XQ2/Sp4qXtahEYIrowbqgrdi2FiFKhoqxwrwZIqob?= =?us-ascii?Q?oiO9ph6UdnJNxbRY/nyxCh32FpBvCpjJSiB11qZTWhPRwmR6Q4b4cgq8bSDp?= =?us-ascii?Q?DyFp4yO5fQWh85GXtC/F8yivK0XQCNTUsr7NgzWKVq5X008VcOW7OFN4K/oT?= =?us-ascii?Q?mwulTqdqq0N7slzn2fAjfo2nnK56GlG52q7woVCHuZp0TaNsj7Nxc/ByDliP?= =?us-ascii?Q?3B2ZsTYKX0h4zZ2IiRGAcCWuVumdNoiK0XfVY5V3YQhmjma7nzaDO/ERkDYh?= =?us-ascii?Q?43gDcM3yKAdUcy1YSL3Yo/KhB0CkajewqjKRyndqs0QBL/BQdZu76DUiUoj9?= =?us-ascii?Q?pY8eXEAsjEDR5Es4RkYgMS0zLgFkCZp9DgrhUNlVwOBIc5wfG7T+x6a1n5Kl?= =?us-ascii?Q?uFH2Q3NNT26t+sYSwKNpUk6hKCpAdSxWIDQ8VppSzx/Q0qOj8UYWB374lXu6?= =?us-ascii?Q?KEGPVeNcGbnQnoWfifDX16iqKHlUObSkysy2oc8+sS4XIn4O7/XZwR8yNBBR?= =?us-ascii?Q?wlZX1d0vSQct92SnxAqt5CIvXhPK7Eu5+jzI/qerrZRTV6on/G6LlEFOmLBC?= =?us-ascii?Q?9GpXuTqkn4Cry/xjyKTB1ucd60ZlCiUrP99lqsS9W9mRJMhvFlbrgsLrf9yE?= =?us-ascii?Q?kOymidIhg5ER7A4kveC9/NlDLCBrhMKhK3gYFMy/+sa2TK346CHz6NGDMvO3?= =?us-ascii?Q?BC58C2sde90NNI/E7/dgPfNsNtRZ1cBgREIZ4K1k71EUlN4YeJcgm3f7LY2m?= =?us-ascii?Q?aVpKkThUVuY8Bh8+42pszPamzUFxGokl8ftFJIOpEoGa/Ae/UcTL4UTyIl8a?= =?us-ascii?Q?2NEBmaumqXSxntquVAXCFuLGxKe69ZPRhSYqaqduqdXxVgWdgxy1pTXbK91D?= =?us-ascii?Q?NVEs3CbYVaCdLTQwt3sr4Wiwu8+ieWvNpXLw4ly0dGdJI0uOEeKhgJFrhVVn?= =?us-ascii?Q?BeYb/inI5lakrESjbDZLwbbg1fdAGAoxCqgsseJxXwL4XjCsygxquyeqKMk3?= =?us-ascii?Q?SvEHjxzfJn/D2CoboV4OOsZLfdI9VSbJm0eFXvBUM+gswvEc4/ulu8QXR2TM?= =?us-ascii?Q?vO+/VgwFRgIC+SXjkPXV8IkytyKR7q4gULoo1/gDXgGOp/xXUOQBFb/AYqJR?= =?us-ascii?Q?e4JnD2YkvTuqM72aLWCI+JTu3WH0hEdJD+iDgbHINUR6F4a/VvM6saWTnWTk?= =?us-ascii?Q?4eYfyHIjnZ4lP/QGlYh8PcfX2yYPvIvVc8NI5YLK7QM23qTz4B+ua38vM1FB?= =?us-ascii?Q?uYPCol5II0vnGHMNTaFJChb1QiaoYB+HbQ0ajEHSyw11RxN0WZBIly3hkftA?= =?us-ascii?Q?B+mBuOnkyse3FgqWupk=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(366016)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Pv6IStIuKRJYPnb7b06RWzGKG+hgLQXA1adq5/yuzoaA0WAkzK4j0tL8XPOH?= =?us-ascii?Q?+O9aqzCg43xwrK8CBtU4pi9idPQ9TqHK2KtH4Ogze/vrKNXiDAvrw9khgnY7?= =?us-ascii?Q?9vss+L7Wafoe/eF50Yo8+ghV7PLNx7FhVrimAAI8+6iUjgE/cbqgQX1NXokX?= =?us-ascii?Q?GaHjVHrYJliNKBmHl/XHuCzXbTMS8UDKguFU+V90rPk4U7cZ+XpVxlucs5Yl?= =?us-ascii?Q?xuBviykERoZq5cbJb0CCB7btpTGX0Gjka4uaXF3DJzhm4C0ELUAG1hZ9cgsd?= =?us-ascii?Q?4sVdqPnbVkJ5qUePo58OGsXoWUzpZPKTNe7MZ2BbqcVamSkJt3eyDlkv916z?= =?us-ascii?Q?/hVZRJSVevFAJJj1nyK92P2GkDIiJvNm4FS2SQRT/lWOA5bp+gqf5NF0olpJ?= =?us-ascii?Q?u3tEwaXH1BWZNdHQ+XK76WYFddKw5NJ4Yv9lZIMX2865/lt0IWonbmUMiiZe?= =?us-ascii?Q?OECoob3RXSRd8zM5OfbMRnYcEAOebfBpIbagkdVgLW7bz1SkpSMl43ttc/vV?= =?us-ascii?Q?/pxIDPT15Nd5Wf6DuKRCbsNXVghvXl3DNlxPrBml2lOu+w+0XFtHomlA57hZ?= =?us-ascii?Q?gDkZSAmLiD2+oY3bcocMEbKPgV1CD8CljPYe2Hp52sVtrDqahHRnKZW8jmpr?= =?us-ascii?Q?S34eauTLQcdYhK9hBPpZE4Rep66N4X0SxQbYdFacRQnJFb5uCdcj0T8g0Y/N?= =?us-ascii?Q?yjQcZIy7nqf4+eNfsylScirUfN1I2dv24uOADPkiQfzLLMP/ZURpFFz8N6Nj?= =?us-ascii?Q?349bkgOZkEqXxCydphoPdkTSHcqHydkCCnUcZEfoGlozX+Y/j2OhW2jU3mnB?= =?us-ascii?Q?WG0ACDMvRT9ePJ2fiTLk4jtF9oHKhN6NVc+RkK9cj74z0xrZQ9FkMjSicD2E?= =?us-ascii?Q?d+c6Dg61QI4Ts7EYNZnusqrWrMmc1o0sYv3YES2WxN5q6ehPh83o7yt62u5a?= =?us-ascii?Q?jsMPgb1DvZT/2ep7y+DotyLcgXdoIIbhPFCTihJjxydAgb0NnGZPcz+zo5OI?= =?us-ascii?Q?72QmVSJ2fA6257hmHVzx8WRHxh7xr3pjJI26KAxyNppstFCkvozGCxgYMgpZ?= =?us-ascii?Q?5O1yy1L1xbPABB0OWzjJezYCY61H3mpoYly6D/TlOKFUI29JY+J/Tv2NTgG4?= =?us-ascii?Q?s4Ahgt70aZSVguKlYdvsfcH2XQiLtPtdWcY8is/oNiOuTanA5mpTxLbQkTX9?= =?us-ascii?Q?F/j5mNr43b4d8QHsi/ufHudg0QKt2s+FvVe3yU3idi22DnxrT9eDIxLu+Sa5?= =?us-ascii?Q?kcIbRCq4FmL9NXSDWGGU8ra15trp/7Qbu8EBLU63h2Yi1kd7PB7+H63kTJ7/?= =?us-ascii?Q?hOz3wNDuPzb5Zyk3IcZbI705ePsuR9x2d4v1SuOl5ODX8ehOGKH12sHcQVHm?= =?us-ascii?Q?wuuU0uVLssORwEpksCmxT0L/uHsJnfk+oVXD3hPb6Rtghb7kc+BenQFZbf0F?= =?us-ascii?Q?URqTlFESQTN3dllr50iI8xjSQJJmPIUteWZ8qVV6GOen/HWfuZpw6q05YYPO?= =?us-ascii?Q?A1kcX+wlQxfFYugGqovtGEoJ8CFFIpSrig5ZcGhfeRBlAllMisAi7P0oflBf?= =?us-ascii?Q?JpdN/sAi4RvbFJW+2S8awZaErgEOLEU+9hBG0IhaVAxFdbL4hTy85T3+4UN7?= =?us-ascii?Q?IcnuforGuantQyaDVA8GjE/POjOzFVUu5E0A1l32XvwDdBMCXSYLI5/o1rnW?= =?us-ascii?Q?ERK7fF4ncXaW/AAZaNmhpp8oXrYAWD8adOzzAs+iPwrwH7w+lkWEygQMUunY?= =?us-ascii?Q?JOnLf+c8fQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 308b4c01-ef95-4192-f891-08de5527a468 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Jan 2026 17:49:48.6127 (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: iNj2D3EJnE6mnpQiDNm+mHq6bMRycR2scWsT80AxhfBSiAPUeXeNhQ/YXFKQNNvS X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY3PR12MB9605 X-Rspamd-Queue-Id: DC7182000D X-Stat-Signature: ky86r64xkimffr8aang733abkxtufmu6 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1768585799-21873 X-HE-Meta: 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 8m/vVPCx C7D33KLPAIm7o4BiKsvLVi3aWWm1ISSN3gKbR+ItjOJnUqJYNha1xJa5B7OQnVmEnEvdPQoUqjWOSFlu//a/LZq4HZ1zonyytiSYNLUmI/GTfLxnlok/w6Ux02ciPuplgGC4Uhv/Anxloa5fhvJoagIzl1AkZSfpiYzeTaY5bNEU0MHF4X05TwPk4Fu+pc+NivqxUuGUHKC9xvEP4o5j4rtQGuZCzDkWGPs3/kVt46Yrp/RYXihjR5i749JN/yTyLo0oDNZsUFGm5fIuTq05qv52H2E/NMaofR/5lfUvA/te5jics8j9b9UELB+v2Z8EvU+dFIdM0THFKxUhDtRSfbTGbc89TqD3ZD4hQCSe7NOon3zirNc8vzrT8w9NZtAqSu/Y5voFDEXo1jcocPznpaFtCTScmYpUJQkTpYXe6296+sgJ+iTXftdC/lvKIvYFfRxgUBSNTQpsJ5aM= 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 Fri, Jan 16, 2026 at 12:10:16PM +0100, Francois Dugast wrote: > -void zone_device_page_init(struct page *page, unsigned int order) > +void zone_device_page_init(struct page *page, struct dev_pagemap *pgmap, > + unsigned int order) > { > + struct page *new_page = page; > + unsigned int i; > + > VM_WARN_ON_ONCE(order > MAX_ORDER_NR_PAGES); > > + for (i = 0; i < (1UL << order); ++i, ++new_page) { > + struct folio *new_folio = (struct folio *)new_page; > + > + /* > + * new_page could have been part of previous higher order folio > + * which encodes the order, in page + 1, in the flags bits. We > + * blindly clear bits which could have set my order field here, > + * including page head. > + */ > + new_page->flags.f &= ~0xffUL; /* Clear possible order, page head */ > + > +#ifdef NR_PAGES_IN_LARGE_FOLIO > + /* > + * This pointer math looks odd, but new_page could have been > + * part of a previous higher order folio, which sets _nr_pages > + * in page + 1 (new_page). Therefore, we use pointer casting to > + * correctly locate the _nr_pages bits within new_page which > + * could have modified by previous higher order folio. > + */ > + ((struct folio *)(new_page - 1))->_nr_pages = 0; > +#endif This seems too weird, why is it in the loop? There is only one _nr_pages per folio. This is mostly zeroing some memory in the tail pages? Why? Why can't this use the normal helpers, like memmap_init_compound()? struct folio *new_folio = page /* First 4 tail pages are part of struct folio */ for (i = 4; i < (1UL << order); i++) { prep_compound_tail(..) } prep_comound_head(page, order) new_folio->_nr_pages = 0 ?? Jason