From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH7PR06CU001.outbound.protection.outlook.com (mail-westus3azon11010058.outbound.protection.outlook.com [52.101.201.58]) (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 3A9071E230E; Mon, 12 Jan 2026 00:44:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.201.58 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768178665; cv=fail; b=AIZZ30u7GGzVG037NQCLrt9MZCd+RUcJkWS3jquu+8W7Zj0ISKYWD2Wi3+yZQhexXH8ZztkCwuiPa2bgwMIvuklodFy74jQgU26AnLY6dEmajZi8Y8CER2x7tgGf//PIxWQ8bBZPQPxZMqQYlJy6NHHFY/YIrR0l500kCudEn68= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768178665; c=relaxed/simple; bh=Easnw9+qHuuw1GSYNMz/gI4Jganf++J0B37zJawSlGU=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=f2yX1orD3bpGhrePexq9CvU4Z1jteI4hOdUp/sRM4fEOeNfpH4UzOip4LHDZb3TxyRz/YSohDMPDKHXBSQrUdfLnmqWQDoI7hrvQ6xtvzZvTF+mRmKVH8C6x2DsqJzJDPXbZJ34wv1w2IqzmpryCRUkxBCptbaZGHKBlbLl9yhw= 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=nIgN65aO; arc=fail smtp.client-ip=52.101.201.58 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="nIgN65aO" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=y0BlQEDyArWG+hHMgW0p9YeEuAWsasBw3xbx18XHgU3NL1lLwBMJdfXcJzjoXCFUrAc6otyDxjba8BMbJOF3KF4Lqz7CYIURpQJxH/RWli5SBWdmRf/OjwZ7bi6m6I3LTxWit/kO+FpFgEKcGEXizWuZ0nCwIIMOsIB2wM2mY9iOzKjyW60g6cwjk02385HR3hWB9TNpV4juNU6orF68pRx50+6MA0k+ZkaXJcGFYZibnGMbPswWkvQj+5D/5XabnREEPEX0V+GCtGUzWF0yoT/rww99CODGgBga92LmAmjhoL9VXuCeXJdrvNe5rnZh0TEdfkz/NBIcOMItT67dug== 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=Z0WB/0W+tWuBkRxqpvz5b781tyJOLPuQPXsjosuVBfI=; b=W40nbtykOyo4GY6y3ZRXuU/Wjlr5OgUVTdyKGrClMNwC+tbl3QZ+mu4kjs5+HX/bMhSEOk7MF2MKsxVxhmiM1kA4T5vd0g15jZ0RQjXui2M0I/n02ZPoFYDNrGupZkrfdAahZr2reWNGnfu6GZPPFQVRnCsMOjovFcH8C43vAKwpSYxZE3RreP7ALtRp2ZYo5M65XydkrwE+wk8rBWBH7arGhFzZmG0TuQBMnQ76I8LMzsW7Q41/EgQzw9JiECP/nzEemEmdPAfac3j93cUVhbKHmVnFGvtnkG2Smr5jw2YiOhO2fa3qijtmO9wPVrJAFcmqddzD5LwbzusnGwhSxA== 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=Z0WB/0W+tWuBkRxqpvz5b781tyJOLPuQPXsjosuVBfI=; b=nIgN65aOfaAZEle0Gbc/ghHh4omwv9/592DXCLID4OErdh5CmV5maKbL/mAX5aQKdzL3eFac47v4pVmhE5wmPm4nihUlJu76Zisyhmiu/cLR7rDK4erdPAJZ3hlOjHIvi2yLcDFsKEM6W9+aAwqgiKB1vgHp+q2Kjmgzu0aO9TpoelTCTrd8tV69prr/ZPM2Y5bbPtbPubb8zzZME3e/bdEHD+vOixLSpChnQ3lZUkQ3eXD3CZQzbAJiL/2nbeZrCONxvCM2/cDQ3fOvbJeyhW2OwHmqoYljWvQf3BENzK2iu0qPYINJhouiIzN/8q4164EHS2mEONh3z7nNr5OsTQ== 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 DS0PR12MB7726.namprd12.prod.outlook.com (2603:10b6:8:130::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9499.7; Mon, 12 Jan 2026 00:44:21 +0000 Received: from PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::2920:e6d9:4461:e2b4]) by PH8PR12MB7277.namprd12.prod.outlook.com ([fe80::2920:e6d9:4461:e2b4%5]) with mapi id 15.20.9499.005; Mon, 12 Jan 2026 00:44:21 +0000 Message-ID: <706ba3a6-5be2-46d7-9e7d-d613f2e061cc@nvidia.com> Date: Mon, 12 Jan 2026 11:44:15 +1100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/7] mm/zone_device: Add free_zone_device_folio_prepare() helper To: Francois Dugast , intel-xe@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org, Matthew Brost , Zi Yan , David Hildenbrand , Oscar Salvador , Andrew Morton , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Alistair Popple , linux-mm@kvack.org, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260111205820.830410-1-francois.dugast@intel.com> <20260111205820.830410-3-francois.dugast@intel.com> Content-Language: en-US From: Balbir Singh In-Reply-To: <20260111205820.830410-3-francois.dugast@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SJ0PR03CA0225.namprd03.prod.outlook.com (2603:10b6:a03:39f::20) To PH8PR12MB7277.namprd12.prod.outlook.com (2603:10b6:510:223::13) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR12MB7277:EE_|DS0PR12MB7726:EE_ X-MS-Office365-Filtering-Correlation-Id: 095a5221-14d9-4bb5-69dc-08de5173b974 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|10070799003|376014|7416014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?OFdIVW8wNHJVYXpTNHd1K0xNZjhHeDZ0a3c1YnhlVzBqa0tZNXJJeC8zd0R6?= =?utf-8?B?QnAyWHZNNC9EMmtSWnVSak4wNEo1SGhZdEJ5QkxmNnhhWHdRYnB1TUpOUngr?= =?utf-8?B?T2lidVpkUFVCSkhuWkNhUFFPWjd0NmlwWkVxSWNic0Zmb0NacGYxNmJ5K0s0?= =?utf-8?B?Ri9vcXJDVk5SL2xiU0c1L1orait5Umd4eXZXdWlzbjNwZkpKeW1BV2thclVv?= =?utf-8?B?UjBPeVg5dFhaMDY0WGZCclRMSDMzMUFuSzZxcE1NU0N6ek05d2tzWFVma3o4?= =?utf-8?B?STdqVG54Q29TVmNXRDA1b1kzU0s5K0lBUWVPK09oOVVNSmZEZ1NmbXNyMml1?= =?utf-8?B?VDFWN2xpYmt5aHdJTDFxZWRHZ2V5U0hoSkxiWnNIZ2lTZ0ozSjRhTUJTbWU1?= =?utf-8?B?MXg3MERPMDJEbDBVU0pVSDdYR0FvRC8zNmpWQTR2ell2aXYrQURveG4xbDJl?= =?utf-8?B?cTYzT2E0UHl2RHUreDFvcnNsb3VZeE5lTmtOWllaU1orY1NpR0NVd05mRjZv?= =?utf-8?B?c25Xa2dWR1lCQjl5RHFoWnZPQmF2THZWOXhFQ1VOQlVEb0doTXhHUnFlcVJN?= =?utf-8?B?a0gxSm94VFQxN0s5WVhQUkZYTExwQ3ArZmp1TUN3aGF2clNha2pOcE91Uklw?= =?utf-8?B?QUlkd3BOWTBTNW5rL3pGRXFzMGxtYWp4ZzdzL2xSQ0xlZFdHR3NKNGtQaEsw?= =?utf-8?B?QnpRZGZmcS9ab21Ib1hHS1Z1YTRFVnQzL3BxZGcvamhheDJNd3RUN2dIUnFa?= =?utf-8?B?cFU3RTBYQVhEY01KUGhiWjZOS3kzU2RCMkxHN2Z4STEzYnArenhGTDBxUFFY?= =?utf-8?B?ZjUyK1E0UGZ4NzdWeHVqaHc3OTNzSnpLOFYySXh3aDYvSnVtWWIzS2E2UUNJ?= =?utf-8?B?b1FHd256M0VKU0NDUHV5WERITHJtanVxNWxBckJTQWVLQVBTKzdMYndDMG1t?= =?utf-8?B?c0N0YUFUdDdxUjNvMzltZEZJVkJHRU5KM3cxNi9IeldPV2V5OSsySmNWNXl5?= =?utf-8?B?N1cwc3VwRFNXMWtTR05vRDBXOVBjR2hldUlzVEZJRTNQcXVrQUgzcDc3WU4w?= =?utf-8?B?NU9tWGluYjZxZGRTaURHZyt3bkwySVVBdlhaZFN6cDVYNkJSTjZOTEVVQmpu?= =?utf-8?B?MUpINEVWVllzTW5FV1RpL3V0TDNPZFhOS0dSN1RHa25DbGI3ZGI0Rng2OHRE?= =?utf-8?B?eDJ4cUE5OEpPb3NsYnhFajByVHlzYXhZOFVpb0NuczZrQWhCbVNnRGh0N0pn?= =?utf-8?B?Um93TXRqUzRQODBpeUJ1OUtuem9NMnI0b3pPNUhTRWx5ZGlHa3RGeU1sU1M2?= =?utf-8?B?cUpac2RXMXB0QndpNkJGU01WQitta1p2d3VsSS93NVFEUTh5c0liLzdacmYv?= =?utf-8?B?L0gxdnZjK3UvdmRFNjZMdGREVStxUzJUY2U3S2FoQUhGNGJoZlUrSXJhQXJX?= =?utf-8?B?ZmZkeDNZOGZ1d3IxdUw4dDRBVXIvUGd2ZHk3c1JGdm9VTnBBbkZDZTZNK2dW?= =?utf-8?B?bFhLaGg0TXJOaGxPcjBSRUF5WFNUQ1JCMVB3ZTBEeTlKRm82bzBUT0FUc1g5?= =?utf-8?B?dVNrV1RTVlpLYW1uQ2d0Z2pkZGNzUHRDUk96bklBSjRGYys1aFBjRnJMNU9F?= =?utf-8?B?NEQ3QldzVXgwVkxVdE1HbVRXOUVDZ1RPZWJrT3hNbDdDRWR1K0paUjI2dmg0?= =?utf-8?B?WUVBajk1V2lIRkc4T0ZBMnJvZFZ0NzBHR2c3am50bVlBQ2JmZTBRY1J0Z2dW?= =?utf-8?B?blE3a3VVRVN2ajJWdkdGYkgvUmZOZ3dOOVNwNE5GYStCeTYxNWoxWWV3SVZt?= =?utf-8?B?a2ZnbmtrSlZScmgwNytuUm9acDF3Z0JqbmE0OEpuYXRBbFhJdzNhM2pSM082?= =?utf-8?B?czBEMjJtcmN4b0RyRXd6c01uczJoT2ozeGFJTmN3T0Ewc0U5Nnd2SkJPSkZ3?= =?utf-8?Q?4fHR5nYx1fgLDGOL5D3ywZpzVxJShPqv?= 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)(10070799003)(376014)(7416014)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 2 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?bStkckYxOUVmTnVEMVRkMGxobjJ1ZFNxOGRlemk2SkcrMFE4MG9NSkRLY0lP?= =?utf-8?B?WjlPUTlsY05hcms2RVdidzNtRlZOVEpVL0RKQS94NnJDR3pJMzdwSmpibUpO?= =?utf-8?B?aWZqd1Z1SEhma3Bkdld4aWFSRDFrb0ZoNWRBVzRjcW05bFRuKzlnM0J4RWNN?= =?utf-8?B?WTU1cFhoUm83MTlJUTU1ejZITW9Vd0JyM3FsR05vSjhRT2Y4NlNZYTB1SXc3?= =?utf-8?B?dEQva2ZDM0ZjM2RXcDFPT0hmcGF6TTZGVzJudml2cHlveW5CUWl4bTNSR1VO?= =?utf-8?B?RXNjZjhVeGJPemk4REM5TkRkeUpuSmxLK2xtSkFCTGlqaW50dWxxS2c4dmRr?= =?utf-8?B?RjhNWk5qbkk2Szd1aW5xZGxFNnduQjhCalk0RDNvTkpsZGFKVFNibGw5ZThu?= =?utf-8?B?RFZ5VEpPOVVRT1dUSkRyMm5mT2wrTm9vaThvSEg3M3FHWS9XL0NqUGdVT2NU?= =?utf-8?B?NFJOYnYrVXBKK25lYkIvME1mSXpQVGtzblQ5UEdpTUF3RGxENGh5TmcvYmVN?= =?utf-8?B?V3F3MURWZmR0V09RZXZPQmpLMVFuakxTNkhROVJudFdOM0NlQVM3VTJFdURq?= =?utf-8?B?OXg1WFNSRlpUVUlrbG1HREllUmFFSXYyYmVWOVE5WjRHbU42c1dQM0xxQVRM?= =?utf-8?B?NElId2kyOFZ1TEk3RHBZR0FaRGNlaEhiZmNwOFBheW5PZ3dNbjhmMTBuN0FT?= =?utf-8?B?aTNBN1k5SDg4eUoyaUxwRHJ1K2d5UVVHUHNrR2dsMG1mT3paL0MwWThLYkFP?= =?utf-8?B?Mjh5NHUxcHZEUHBCUU5xU0xLaXE1WlA3N21DQ0s5RkhoeUxGSU0veGZaSGJ5?= =?utf-8?B?d0tJYTdBOVIrVzlBbmcwcTZqeTB6dExHSnN0b3RtMCt0NW9yNlpXT2pZMFZC?= =?utf-8?B?Yk8vWkRocGdFTWZoY0thMGkyVTR2VTNPSHJMeDBucStoZFpIMWN4bGlxRXhx?= =?utf-8?B?QmRSMFcvQmtpT25XY0c1V0pFaWgrbHNnd2lDd1JTZVM3LzB6SE83d2YxMW5h?= =?utf-8?B?Si90NXdndmJPZ092cHBXRWtiWUx2TnpUejF6OGdaWDlRMzRXSk84c3N3VE5K?= =?utf-8?B?K0I0VXFoRXdMeTM1em5MbDdielI2R21EMmM2ZjR3K1lMSXl4eGdubm9ZaGFC?= =?utf-8?B?cWFTcDArVjV5UjFFaGZhM3RTVUZpVCttVzFSM3ZFbHhpZ1ZaakgySDk4d0g4?= =?utf-8?B?YVpJTml3RzdMZ1pLNWFCUFI5OEduMUtlKzJHWDZZN0Y4Ry8rM1A3R2F3OUlo?= =?utf-8?B?Q2tERGxCU3NIT0piR2o1YUZ6dEQ2Q0syd2xDSHFzZ1JidWo4Q2kxNlhXQ3p6?= =?utf-8?B?WEg2NU1IU0ZsVm1NS1lDMGNvc01rdzAzbVQ2TnA4VzFMSkptZ1hOdnJkd1NK?= =?utf-8?B?ZW9peUYrQ2owcHVBbk5zRUJwbkNkRWNnUkozdXI3MHBtd2NpTHFaWStUSDVV?= =?utf-8?B?UmdNN1lCRzkzT2dwaXdMSzRhTENZSWZ2Ync4bndqTWg4bWxrUnFJRjNaZFVL?= =?utf-8?B?VjRpTzBRVVppN3pNT3NOemI4RXZmZkV6Kzg4QnQveHN1QWE4NDBHakxHV3dN?= =?utf-8?B?OWFXWW5WaUlnUXdwTUNUQW8rcUxZYjA1d3ZwbXBoS3VDazFKcmVwc0xaTlhq?= =?utf-8?B?M1JvNExnUGh2THNZZCtmaGx5MUFLRTFnZktzYWNucDhhQnZVRUxQV2Y0OTRM?= =?utf-8?B?Y1cxbmk5dCt3eDFOaXRyQVhlL05qc2ppdHUwVU9ZTCt3OTNwK3hCMDZUUDJK?= =?utf-8?B?Q0RtL0lnZjJiSXA1bER2YlY4Ny8xRmdvL2hLVzhoMnR0OUdoakRnLzM3ekpp?= =?utf-8?B?cVUwSjFBQU8zOEcrd1hjbTlwa21UMTNiRnJ5UzFCdWgrM0ZpR1VtNE9YNHRI?= =?utf-8?B?TURCbE4vdFpQU0ZuR21IbmNpTXp4R2FpTlJQV3NyQkd5MGZkWWhLUnJnM3FC?= =?utf-8?B?VjFWeGpnczhSK0xKUzZFSVFpOGg5bU43WS9pUlFRQWlWRUJDcFcrU2NjTDkx?= =?utf-8?B?WHBrTEY3MkYySG1hWjM0OWNsZ3hxM3VwYkxYTG5JZEMzWnhNZU50cC83bnpO?= =?utf-8?B?bHE1TitsZXFiRklIekJNZzBNMHFKMDlEMXhIMUxDcmRhUUlsYWhsdHRPK3RD?= =?utf-8?B?L2lyWnY0TG5mckhJSGQ2b1lKZGcvSFZSTDkrcGF2eWVwUlpLYkd6dHlpaEM5?= =?utf-8?B?M1YyWFlPWi9tMGNNSmNFOERHeGppZ3prSmpobDg5NUZ5NHlkWGpMWmZXUEZQ?= =?utf-8?B?UmQwUHFkZzUxd1Y5U0ZFU1R0M1Z4eFBDR2N4cE4rZCtDSWQ4YjNBR25MYmdK?= =?utf-8?B?Ui85cDlmekVsRzlNZHlxdllNWENFUXpJYnoyeVhiVE9lclJ6NzlJRnYrSnRD?= =?utf-8?Q?DYOgFj9uME44xiF3R1whXOqPga57kBZIjhfX1/2Wj3T77?= X-MS-Exchange-AntiSpam-MessageData-1: egj9jOKQneAR7w== X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 095a5221-14d9-4bb5-69dc-08de5173b974 X-MS-Exchange-CrossTenant-AuthSource: PH8PR12MB7277.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Jan 2026 00:44:20.9180 (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: /MD1V/u+bCdV3AsLCytvF99+CQ6zBi5fhJh3jrRewpSgaFCKAeoF1vJuUfFKHy4chgCp/3dtOBPiEcxWnfMO+Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB7726 On 1/12/26 06:55, Francois Dugast wrote: > From: Matthew Brost > > Add free_zone_device_folio_prepare(), a helper that restores large > ZONE_DEVICE folios to a sane, initial state before freeing them. > > Compound ZONE_DEVICE folios overwrite per-page state (e.g. pgmap and > compound metadata). Before returning such pages to the device pgmap > allocator, each constituent page must be reset to a standalone > ZONE_DEVICE folio with a valid pgmap and no compound state. > > Use this helper prior to folio_free() for device-private and > device-coherent folios to ensure consistent device page state for > subsequent allocations. > > Fixes: d245f9b4ab80 ("mm/zone_device: support large zone device private folios") > Cc: Zi Yan > Cc: David Hildenbrand > Cc: Oscar Salvador > Cc: Andrew Morton > Cc: Balbir Singh > Cc: Lorenzo Stoakes > Cc: Liam R. Howlett > Cc: Vlastimil Babka > Cc: Mike Rapoport > Cc: Suren Baghdasaryan > Cc: Michal Hocko > Cc: Alistair Popple > Cc: linux-mm@kvack.org > Cc: linux-cxl@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Suggested-by: Alistair Popple > Signed-off-by: Matthew Brost > Signed-off-by: Francois Dugast > --- > include/linux/memremap.h | 1 + > mm/memremap.c | 55 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 97fcffeb1c1e..88e1d4707296 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -230,6 +230,7 @@ static inline bool is_fsdax_page(const struct page *page) > > #ifdef CONFIG_ZONE_DEVICE > void zone_device_page_init(struct page *page, unsigned int order); > +void free_zone_device_folio_prepare(struct folio *folio); > void *memremap_pages(struct dev_pagemap *pgmap, int nid); > void memunmap_pages(struct dev_pagemap *pgmap); > void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); > diff --git a/mm/memremap.c b/mm/memremap.c > index 39dc4bd190d0..375a61e18858 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -413,6 +413,60 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn) > } > EXPORT_SYMBOL_GPL(get_dev_pagemap); > > +/** > + * free_zone_device_folio_prepare() - Prepare a ZONE_DEVICE folio for freeing. > + * @folio: ZONE_DEVICE folio to prepare for release. > + * > + * ZONE_DEVICE pages/folios (e.g., device-private memory or fsdax-backed pages) > + * can be compound. When freeing a compound ZONE_DEVICE folio, the tail pages > + * must be restored to a sane ZONE_DEVICE state before they are released. > + * > + * This helper: > + * - Clears @folio->mapping and, for compound folios, clears each page's > + * compound-head state (ClearPageHead()/clear_compound_head()). > + * - Resets the compound order metadata (folio_reset_order()) and then > + * initializes each constituent page as a standalone ZONE_DEVICE folio: > + * * clears ->mapping > + * * restores ->pgmap (prep_compound_page() overwrites it) > + * * clears ->share (only relevant for fsdax; unused for device-private) > + * > + * If @folio is order-0, only the mapping is cleared and no further work is > + * required. > + */ > +void free_zone_device_folio_prepare(struct folio *folio) > +{ > + struct dev_pagemap *pgmap = page_pgmap(&folio->page); > + int order, i; > + > + VM_WARN_ON_FOLIO(!folio_is_zone_device(folio), folio); > + > + folio->mapping = NULL; > + order = folio_order(folio); > + if (!order) > + return; > + > + folio_reset_order(folio); > + > + for (i = 0; i < (1UL << order); i++) { > + struct page *page = folio_page(folio, i); > + struct folio *new_folio = (struct folio *)page; > + > + ClearPageHead(page); > + clear_compound_head(page); > + > + new_folio->mapping = NULL; > + /* > + * Reset pgmap which was over-written by > + * prep_compound_page(). > + */ > + new_folio->pgmap = pgmap; > + new_folio->share = 0; /* fsdax only, unused for device private */ > + VM_WARN_ON_FOLIO(folio_ref_count(new_folio), new_folio); > + VM_WARN_ON_FOLIO(!folio_is_zone_device(new_folio), new_folio); Does calling the free_folio() callback on new_folio solve the issue you are facing, or is that PMD_ORDER more frees than we'd like? > + } > +} > +EXPORT_SYMBOL_GPL(free_zone_device_folio_prepare); > + > void free_zone_device_folio(struct folio *folio) > { > struct dev_pagemap *pgmap = folio->pgmap; > @@ -454,6 +508,7 @@ void free_zone_device_folio(struct folio *folio) > case MEMORY_DEVICE_COHERENT: > if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free)) > break; > + free_zone_device_folio_prepare(folio); > pgmap->ops->folio_free(folio, order); > percpu_ref_put_many(&folio->pgmap->ref, nr); > break; Balbir