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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71C9AC4332F for ; Tue, 14 Nov 2023 13:17:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC4996B02CD; Tue, 14 Nov 2023 08:17:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E75056B02CF; Tue, 14 Nov 2023 08:17:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D159E6B02D0; Tue, 14 Nov 2023 08:17:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id C37AE6B02CD for ; Tue, 14 Nov 2023 08:17:08 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 95F0CC0823 for ; Tue, 14 Nov 2023 13:17:08 +0000 (UTC) X-FDA: 81456610536.13.9C7DF15 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2041.outbound.protection.outlook.com [40.107.236.41]) by imf22.hostedemail.com (Postfix) with ESMTP id A1BC2C0017 for ; Tue, 14 Nov 2023 13:17:05 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=Jp+lSLB+; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf22.hostedemail.com: domain of jgg@nvidia.com designates 40.107.236.41 as permitted sender) smtp.mailfrom=jgg@nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1699967825; 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=UKySM8axderqUF36ppd/y9BLQ+m9RHxr8QQ+Iu3DPjg=; b=zU222e9YXOXRtTAHf2qAhllJNBC7NuE/2VycyEoR/GIlHtvvS2K8AiH2P+DIpgFuxB4q58 AdrlAO4RIUWM+Ku283Vwu2ZJU1bA5PLPEGq1/e4RkkCFl2Hbovrb60gyBExwwP1BTMDd/m zvhFpfRKJxAfS3JHOGUaeTL272PKBtE= ARC-Authentication-Results: i=2; imf22.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=Jp+lSLB+; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf22.hostedemail.com: domain of jgg@nvidia.com designates 40.107.236.41 as permitted sender) smtp.mailfrom=jgg@nvidia.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1699967825; a=rsa-sha256; cv=pass; b=Q6KXDIbzS6K8xbu3j6pHc7zVfxWV+ODaG0oPVR9SiJP/s8pQnR475Fd5cyFhmVJnUkjrx4 BKyDdEi8a95wvMSuCG8E+As7wB7BkHemwishcgq66Bgk88CPnqblU5u4KTUbfFJ0wWd9Gf S03Yz1d8GFfanoBgTY9qXMtJpl6NqpE= ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZGFWxz0bh0t4IWwZxB+ld9cI7DygkGbfoeTXG4ZbnaSVbVDynY2hhP9Cya3l2K9TkLWMrQGPkU6cWRAhPVyXOBAI+Zkr/KfJPCmSiaRQvWyXU16GLF5df2Vu7+ARIQJfRX5bToT9d+wUbYiPnCXtDSCxPG5dcP46Xww8ud/sRb1EKHyhOxUOEmkSZjsRG7B88NO+Lq+8Jj604m0OryuGVA4i/7/yYLGh1h2hmhNqs1jiSvv+WnbLRu8YCisAcFXMc+Ud/Yv1voI0t1O7HQAwEiLh44CltjumMO8svooa/+pywYHrpsoDISa8djXa93oUy2/6QUTO+jIT6vXbmCI7OQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=UKySM8axderqUF36ppd/y9BLQ+m9RHxr8QQ+Iu3DPjg=; b=QJ14X6b64L01Zw/AoAhXD3CMgzpiyii4350cq5tJoLT9RIxUf9xBkTfZkn5GDNx9erV8z0GwjjdVxMxhDoJ2kxoZEFaZKngUWMyqxJXXjJ0lbxFqhrDfRwwtLjzPo/sFZL03reVsUo9qdqIlNpCtCqsMM0tD85eRxHfn978raLhY2uTmwVx6lc1Ayd4I9IjRGr1y+UlFmF9au3LsW7n9bYLTuKY9sKjLlte44bVE/xlNM4kfuVr/KI/jhDkGkS+5GaQ1QQ4gtAf4BXRgkEz/uJYOq37P5E/H/wSKohaY5E/yshFjVQJzTxt4UOD+NuTt4AS9tQ82CMnHwTl5fqExSA== 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=UKySM8axderqUF36ppd/y9BLQ+m9RHxr8QQ+Iu3DPjg=; b=Jp+lSLB+viRnwHUEhjUwY0DEgaUrRINR8IrjgVBw/rtjYfb5iTb7uUC85pwf6b0Kuv4fJBIvBzgoQ3Q/CFzF7v/AcxBxgjgpJE/c+lYLZRfQvjePWC/GP53b0uvDurdm+zjYfJZ/7M+0qP4Km+wQplj9ZzmUw1OlrzUSCkDLLEMmTA0QiNR0Kiwhw9UmOA6PqZmbH3wI0F7f1oqA38MF6AnOQnFmsGZz1R7Pa+gu2yU098H+D3hfwoiYYJvb8giCh6gBg5iBXdb5sJ/3yicvj1A9ChlenCRRFsHyq88KKzyKnHt9Db+Rz+TnIs0XLUfNNBxLz3CHJ0WFXJruHQr2vA== Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by PH7PR12MB7332.namprd12.prod.outlook.com (2603:10b6:510:20f::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6977.31; Tue, 14 Nov 2023 13:16:59 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::60d4:c1e3:e1aa:8f93]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::60d4:c1e3:e1aa:8f93%4]) with mapi id 15.20.6977.029; Tue, 14 Nov 2023 13:16:59 +0000 Date: Tue, 14 Nov 2023 09:16:59 -0400 From: Jason Gunthorpe To: Mina Almasry Cc: Yunsheng Lin , Jakub Kicinski , davem@davemloft.net, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Willem de Bruijn , Kaiyuan Zhang , Jesper Dangaard Brouer , Ilias Apalodimas , Eric Dumazet , Christian =?utf-8?B?S8O2bmln?= , Matthew Wilcox , Linux-MM Subject: Re: [PATCH RFC 3/8] memory-provider: dmabuf devmem memory provider Message-ID: References: <20231113130041.58124-1-linyunsheng@huawei.com> <20231113130041.58124-4-linyunsheng@huawei.com> <20231113180554.1d1c6b1a@kernel.org> <0c39bd57-5d67-3255-9da2-3f3194ee5a66@huawei.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR17CA0025.namprd17.prod.outlook.com (2603:10b6:208:15e::38) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|PH7PR12MB7332:EE_ X-MS-Office365-Filtering-Correlation-Id: 681df35d-21cb-4515-29c4-08dbe513fbcc X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(39860400002)(346002)(366004)(376002)(396003)(136003)(230922051799003)(186009)(1800799009)(64100799003)(451199024)(6486002)(478600001)(36756003)(6506007)(6916009)(316002)(54906003)(6512007)(66946007)(66556008)(66476007)(38100700002)(41300700001)(8676002)(4326008)(8936002)(5660300002)(86362001)(2616005)(7416002)(2906002)(26005);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?LMyTwaf15arbkFLhMC8Wq0aiG83PmhT1GNLksFTQDHKle3LlhuGfoGxAUFk5?= =?us-ascii?Q?ftexRSwWX+Gy5DI90LS6YiBB1zHeDSRC5R2R1wTwsiO/0qDQs0mQwQYr2shx?= =?us-ascii?Q?KCq16FCQZLq0FZ2AGzzr1MZTE1DFNukhubq0VrVxQ/OS/c/5Hu/AWJYvMOCG?= =?us-ascii?Q?OmGXQp7f+PhleQJyx/Sy8Q2rVtmsubxBX8/HrlS4GOb3FrAdsS/2DZSOSLy4?= =?us-ascii?Q?csIJ9qNKTSLwQBQUwIlcQ8Su+CKLP0JNkLb+RyDfiQglzx9s27EuHhCkbNXb?= =?us-ascii?Q?RI1FjWozhmRHF4uHN8E+P/OiJ0TqPUrX6qlbCRrWb3OfHbWf3G8WZa21Zp50?= =?us-ascii?Q?ZW0Jqbt8KvEaQqjdvmp70nbR/w2791rh/IPiy6u+N/kVbVobdper70hdSEC9?= =?us-ascii?Q?EdLhh0GmdOjOB8+knbi1Sqgiynme2R1h09eYibX3A/5duKrM/LwBPjpEUgeC?= =?us-ascii?Q?K02Otwa2rngMicqGBSt5wa27MiC+Xs37ZnMKCilQ34gNdIpR7JfIhjHH7LrI?= =?us-ascii?Q?GgYPBdQjSLIua1frzhB4oIeXnDJ6tCHsgOmzr5CHFIe45fNZoTW0IOwunMbI?= =?us-ascii?Q?kkkZFgo2pwB6wLzQTtxMDhopjLJqDVcC4g0XTn//M0yutXpNqH7n4X7suZUx?= =?us-ascii?Q?rTDwN6QfyeCSpTJMuQIOlqncrYYGnpV20nM6TvXHKsbBoWusoSVk5MYSEwQZ?= =?us-ascii?Q?KGojnEEI1de1/JIZ2I8VLkw/3RcYwbeeSNztOOtSU+B4mmucRmRmgJC9escF?= =?us-ascii?Q?/qF/U3HQRM8xMFu8E1J94ReZHCOSObP0ENks4iDzoeKAUXk2TLg4Ku+8BBrI?= =?us-ascii?Q?lWRoqSpl3aOOmcZvYsnhgYsoJVxQfq5A/uMfKEaVhF///ox01wfsMdPnEWr4?= =?us-ascii?Q?7J2EAcZMNTgCzPtz/9pJ62/hJQvDqo3vVJc+xgvrv2GnSgCa6SOolwOiXwiI?= =?us-ascii?Q?zlm+tEpWdA3dj1WJJ8waa7nhUC62RbOEwb4Y+WIuhBhQ42CAxIcpldmeQwE4?= =?us-ascii?Q?0GM8ca050SSdquBFdsFuOrIaH9OtJN3iM/6gQl2TcpU/vMICqr2sStavBH+z?= =?us-ascii?Q?DWlVRJ0exLX3rHtcvCX3mqUTvUbD9Z5Wu8dCkO1rlqlwUJOk2eNy2RRiRfM4?= =?us-ascii?Q?SHnXd1/7WSm/JPXdWTiXNeX2nkUOFAlhquiJBZf9nq5qBgzEv392fifm4ROf?= =?us-ascii?Q?y9bKco8MjxXK7HQDc1SPmzPT+eGVFuMc1IAsTYkpINHlvaI9cpKXbrO4TVIG?= =?us-ascii?Q?nxM9N9dj9WGnEimPdK4/5ENYc8SdyxCXF6WyRNBc/PS3oFWqymv+cek7Jv1X?= =?us-ascii?Q?Wfw6Qm0hQeYeRMCNW4eBhLNs+Gn7YuDSZ7mOkMbeA7V7wVhXDcjYA5sMzPjA?= =?us-ascii?Q?BQJi9fvg2OqhUBKQyBvWLzNgZ1zIWEJnX78eORGD2808t/sYdPJu08LyPfDg?= =?us-ascii?Q?72iYBzAPsY83B78S4tbcrrpNpfEpumFwWXIU1q+XITSVtmvQPL8Yp15GhZZm?= =?us-ascii?Q?TiduvGIHVGRx+SDzRdAXj9rX94MDbdwDDg6KdbcAyfGz71GeMEFMrwxW04Wk?= =?us-ascii?Q?wqq7G2BZETn3GE3SduM=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 681df35d-21cb-4515-29c4-08dbe513fbcc X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Nov 2023 13:16:59.5803 (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: /qN8X/KasZ+/UrECFUunJt3TNALDiC+2J5oQm6t2kA7qRt+wAKc1FFrA/qB6ZMs8 X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB7332 X-Rspam-User: X-Stat-Signature: hffqdjfth9yudwdua6wr7r8wesrwros5 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A1BC2C0017 X-HE-Tag: 1699967825-661064 X-HE-Meta: U2FsdGVkX1+Nzi76hgw+LGpOD0/8ngv/sCU47d4TZMrnOuZ2EXlb2qkrswZmwbsz7+w6Cr0atALSBmUUQr/rsujibics3tW86PvXDjRR9C1reDhmUAvoSlFqv+TAusEh+gDpVKaxJV2yoIMlkE0xnw0LXLdPu4p/DNjDmS0BEZGbrO/2P+5zO4IDqYM28xCTxQlqsOJagkJEwyThPmO5dAy1UinZNxgESlqsJoi6v6Bv72LZqauONd1c/UnLA5W1PYmiaFCeK9rl+9vzyVNJ2kMC6e8nEo4u+VjkxpJxOqFCcuLHRm2kmxm+rDy83GejVbgA0l6QlbTUM/ZFujlzKeAPP6jkNB6BqBUBjzbRH69WAvkUGi40TjS7eyY5zL/T8lEOJuQmtFZWTXkbKEtGvj9v+DGKDMobdxX4pH3U6Cx/ntzjJKnnh7cxwjQxbt9jJV+oe9TbvrTBmskfGrxM//Z3Ku5QcnJDwsMfzoDjupM7GmxQyaMAmP7GvGRci5kvLilRELWO8o54q25oYnPYh3rC6J8OhjJw1hvXAXGglnj79El6mAXGSjW4qA7qH3L6JM/i35lb3V4K2/r7obu8ZfYEqiucMZYuc4Iwnay3KUN1hCXbbZ8dKIhMQZakbxdi+kTWG8UUkROm2kLmjRBRjeFZRIVFbfZ949Hcn7/8Er9KzKq8hyv6v5QzDnGyOHPGbt7DV64kn5U47ICbnJDwmCONOWTE+/VtinUoqqFGSJYy0Yxu3m3THMaZlLWQ9VjaN9MC1D86zHwwohFX7M/6glYqG+IbWShpfTnCetgyomr45sclIVl6aZJpGMvm1bYGWbJ0XXWpKzWRLrr2ALjqnw9CnWq9gFY6xtalCXLHUCzpyyYUVCo+lr+3xRJ8X4hOU9Cz12ltkwf+fZK8+gtE0YoBKHW4W8IzLHln+mT9PLjCKcOsVv/inU7j6Xnb6AJICJDkiDgorGdkvhVJ2By OLqh3r5H k8F9B2KHXgNm1zfdtoyEtiYLwL+R3wcwFbF/sGsSgX9oH/RDB6xxjTJCyj952maH8P1Wm6cNr3U6UMF64iaer7Hh3YGi9n+AtwtYYsfwYJGeCkmyGu8CVaKofzCAbMNxl4pl6kHEeIyKxg1EuLc0wuFoWtmlj8Gsvmq27WoXAf02nxIXaIV2hR73BcSgJsgqjFB/jUdLZXnn7ZmvmeHnL4bK8cg== 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 Tue, Nov 14, 2023 at 04:21:26AM -0800, Mina Almasry wrote: > Actually because you put the 'strtuct page for devmem' in > skb->bv_frag, the net stack will grab the 'struct page' for devmem > using skb_frag_page() then call things like page_address(), kmap, > get_page, put_page, etc, etc, etc. Yikes, please no. If net has its own struct page look alike it has to stay entirely inside net. A non-mm owned struct page should not be passed into mm calls. It is just way too hacky to be seriously considered :( > > I would expect net stack, page pool, driver still see the 'struct page', > > only memory provider see the specific struct for itself, for the above, > > devmem memory provider sees the 'struct page_pool_iov'. > > > > The reason I still expect driver to see the 'struct page' is that driver > > will still need to support normal memory besides devmem. I wouldn't say this approach is unreasonable, but it does have to be done carefully to isolate the mm. Keeping the struct page in the API is going to make this very hard. Jason