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 6652DEB64DC for ; Tue, 18 Jul 2023 15:36:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C9411900002; Tue, 18 Jul 2023 11:36:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C42868D0001; Tue, 18 Jul 2023 11:36:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B09BD900002; Tue, 18 Jul 2023 11:36:39 -0400 (EDT) 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 A32518D0001 for ; Tue, 18 Jul 2023 11:36:39 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 0C13DA034C for ; Tue, 18 Jul 2023 15:36:39 +0000 (UTC) X-FDA: 81025134918.01.9F3FC9E Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2076.outbound.protection.outlook.com [40.107.243.76]) by imf29.hostedemail.com (Postfix) with ESMTP id C70D2120023 for ; Tue, 18 Jul 2023 15:36:35 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=cC6g2Ww4; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf29.hostedemail.com: domain of jgg@nvidia.com designates 40.107.243.76 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=1689694596; 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=svJCf61aMa71sCBEXDPhY+QQTJu+Qrm9WmtYKFFTsEc=; b=XVyUhoHNs22Va2K0381RvjQwHe49FLaXspwXDz4ovQPSFEgThgTeAhlBzlkKjZbxNsjq+W xRLBTcGknnHgHWm0GRtqiyOcHFzkKkIQ1sM7cadmpCjPfBMpJi5jqMfZ8hvbEN1yIY+H2e CH1mNvdQ2aiKVqVg/PmqI1FeG2dFv1g= ARC-Authentication-Results: i=2; imf29.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=cC6g2Ww4; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1"); spf=pass (imf29.hostedemail.com: domain of jgg@nvidia.com designates 40.107.243.76 as permitted sender) smtp.mailfrom=jgg@nvidia.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1689694596; a=rsa-sha256; cv=pass; b=lHJqp+qbFQJZogmy4X9sEyuWtQe5tGkYyqnDD6UVyAUGFxgBZyGPv9IYADRZNBdvrDTeUm iEn/Q0jSnzcOGQd+DVv04vcIcNLKh/J2mZ71f8EVVJviv5ye+Cb4DY8hIsn9qBJLcXubf4 JDkjPnWOxWvC3P0iT5h2CqcBJHbR1bQ= ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Id6+wrlM6DgKHm/mdNhsf4no5a1mA2hOeuVr1DAT0zhlLJ5Jzl/yRM/HJNC8vjSGfQbmuCbO4ZLjm3lG0tyf6CTagsrqPzjgXFlYrnpjDBjb0A4fdAypvyMJrAXYDiu5kgmyzgRt6lBh1Yji1FhI/ZduDDUDJJkjobsS2AIP4W2WPXPPozAirKcTR69p9E7+RUDr8p8SFtHnhIcWY6Ylty+Pc4FBaqxxMfftwpK9gxtkxPHzCA63EQurRzBa+3knZPIVBW2XGjcsLNwypFQDR8Fk9Wp9du8qBmVdLmS2kBkB5dqNY5auFzDSlNPanADcZwl8XVYMVeZZKsmRxRZ/xQ== 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=svJCf61aMa71sCBEXDPhY+QQTJu+Qrm9WmtYKFFTsEc=; b=dULKLga4ivVh12TqiPmjFXJLuM5mA1ncsTgor41JSo9CncIA68IegUVSFx7r4zaVhSaDHTtt4i95bpnu6yozExFzp8oDqrVXtvawUXzDmKl8Rt09gjJk/TLzgKhCQIDSYmhpEqB6a+CdXt2nxiKw95QgK7Vumje0cewiUcG76JvH7NfvW6Vd0wF5QoFsTKz6vQ/meiCCruPXQUL0BAHIks/cHArhYSg8rCav5JDXCQyCpPWsKTMwc+ATKQ9kqiaAVN9zTLM86bQ7brb3jT4cSWhiU9H16dTc95aOnvGqVUjj1z1HlZqKVAgW4H00bKVjtWDB5ioWrvf33CLIi6o6Ow== 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=svJCf61aMa71sCBEXDPhY+QQTJu+Qrm9WmtYKFFTsEc=; b=cC6g2Ww4Ch5yGxUSSF0BhLbr0vKj/m+kiSm/zpHw7FYYyJ/Kk7Cx9h4FIgt0Hig/ybJPSW6RiSyE6Vd0QAZzg8w2GIJZksKhhmVLHU3ANOFk7lNR6Rnn+F+758FmwcQzl9HIrEYALG0tUIzqBDGqpEL2tbxEUX0lzH6sAUVujhi/hpQLuHxYNMh2R8nSfjVvv7+QSsWjpno3mtzabcImPRzLqGuAVNq1vkXFiSE00epzWwM3+AJEWEwfyhh7bWB7Fg+D8pMOnuIQ5zKOyOWRqOhpkqGqLS5UDhZfXYxnM5Un3mDDSpSV+gPI5OEFbH7hohptGc3pmS5xdAXUsoZlyg== Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by SJ0PR12MB8116.namprd12.prod.outlook.com (2603:10b6:a03:4ec::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6588.31; Tue, 18 Jul 2023 15:36:33 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::5111:16e8:5afe:1da1]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::5111:16e8:5afe:1da1%6]) with mapi id 15.20.6588.031; Tue, 18 Jul 2023 15:36:32 +0000 Date: Tue, 18 Jul 2023 12:36:30 -0300 From: Jason Gunthorpe To: Vivek Kasireddy Cc: dri-devel@lists.freedesktop.org, linux-mm@kvack.org, David Hildenbrand , Mike Kravetz , Hugh Dickins , Peter Xu , Gerd Hoffmann , Dongwon Kim , Junxiao Chang Subject: Re: [RFC v1 1/3] mm/mmu_notifier: Add a new notifier for mapping updates (new pages) Message-ID: References: <20230718082858.1570809-1-vivek.kasireddy@intel.com> <20230718082858.1570809-2-vivek.kasireddy@intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230718082858.1570809-2-vivek.kasireddy@intel.com> X-ClientProxiedBy: CH0PR03CA0323.namprd03.prod.outlook.com (2603:10b6:610:118::6) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|SJ0PR12MB8116:EE_ X-MS-Office365-Filtering-Correlation-Id: da510a89-77cb-496c-d3bc-08db87a4c340 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:(13230028)(4636009)(39860400002)(376002)(136003)(346002)(396003)(366004)(451199021)(8676002)(7416002)(41300700001)(66476007)(66946007)(6916009)(4744005)(8936002)(15650500001)(66556008)(2906002)(6512007)(6486002)(54906003)(86362001)(4326008)(5660300002)(316002)(2616005)(36756003)(38100700002)(83380400001)(6506007)(186003)(26005)(478600001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?TwtRCythGQxKAezAS7YKLGRsFfmNxnulsaK9e5AOF5jYCyf7KnPzQwOOBggL?= =?us-ascii?Q?bKaHZ7bA+aAA//IVCK4wXFRHFU0bVRZpOfY8vsVAKNPm212aVzGxpSsyBYFX?= =?us-ascii?Q?wAtAY2Vi67iRCGBICLB/ZkqT9sxCDkfzINN9x4OmL4M20toRYHek5AcAoltT?= =?us-ascii?Q?heJmhLVps1qQ9p2DU6nGaVgrqeQq+ur3GGaxyAf05BO5zkEhQnNvhgZ5DBx+?= =?us-ascii?Q?RV0Qy6lFD6QP7hSmotiaXsv5qkP1uL5HAMAHdTsne4z/CYW5t/zeuAMlf20x?= =?us-ascii?Q?CJch54YN+uI8MoEh7CCD+CEYF+dc5+wkHgL90oJXNLG7w0ux1zSHHZLrJS7o?= =?us-ascii?Q?LgZ0rPIU8Pw1qEDgF3yooypEH2cp0kUANhHpZ8/EVEMMaHNWktVaLIyyrENt?= =?us-ascii?Q?ChdIZ+k04F5sTKBUG3MFbdvyqW9RG1rHYZogyYXr5y9yCdi+HUBEiY6CsCB2?= =?us-ascii?Q?onlmgqHpYIvcId6t2Pwk9/yw4zcuk31+9qKTdCWPnskBVhe5hMiHIFHyfDDs?= =?us-ascii?Q?D6VeHRA7YccoZmdzV/3g6cyIooGUDPSd7BGXnFhfuoX6frqFgprzsC9sHlDK?= =?us-ascii?Q?R7II3rEbnkLqCIxsL/8BjJJFwd3x4XZ6Q/cW+BVvxZEao7y5h+5QduuTwTJ+?= =?us-ascii?Q?VtrwMnsdUrXAlJ0fCGHqdnhGzvdoGJRTZPt1CEp9lJTbejZNpoaO4i5wThZQ?= =?us-ascii?Q?LdfHIMRsOSM9xgvFSLOzCKUqLXCdVUEsEqKtWZymGO9nBiz9CRz04TZTgw/I?= =?us-ascii?Q?hzR0+4Nw8QbOnOwzfZlFN1gSKLFPnUnA20y39ArFoZWW9cWEzyeD3ZOMFMiZ?= =?us-ascii?Q?OpixK1FwLgUDdyjmg3LZVbbnXF5ta0J6pLTrwuFGl9uer6q+zyqeFDhZETGb?= =?us-ascii?Q?grdnCqbA71DcZm62fE8yEKvzZBndLsQjp6DCD8L5ftjFlOA8Ya+A9XcJTt4e?= =?us-ascii?Q?ahn+zEX9bqePRVcd1lPyZDJ1PQV/1aRoUx9w4yXG4F9zocMkwFYHr15rNg2S?= =?us-ascii?Q?vCSTF7jOi0G/ocDjZekm2O449gx4bilu2cFwxRoHmSqYTI8xhD9dV8yb82DO?= =?us-ascii?Q?t/jkKRsUasbuEeqlAtAIN7iAOYU5B9OMjJwXpDV2oDBRdcWkW3gd+XUz2buj?= =?us-ascii?Q?/0DG+FwNCwpxjlN2J68Voy4KSWcpWUBoCcynifOMBBRFB16G9J7jeefMiiaP?= =?us-ascii?Q?J3N/xzV18Jpb5ivJ5HkwZ03zasGMfjWvpYfzqJ3N339XhdFO3OnpR3okLwwe?= =?us-ascii?Q?JxYqySZtlcbOeDku69lAoS/9ntyqtx+uOUE5hZMyrY7azwyV9Kx6hI5MGUP9?= =?us-ascii?Q?THMbCe0bwN9dFVd7xE+3+VyLX18ncUMBkFpr7GooFaX+ihqDkfXQED7H9grM?= =?us-ascii?Q?+hJJqPJL+egTxmUfCO4L49/Q7NHcLKkvrHsx3cWKU7EjYG5NRk9fWufXz7i0?= =?us-ascii?Q?EHjMu6xT0vkMuzCRyl7ab+opUVZpmfhzAVC1Xp3nTOovGRogXk4ikFv0Dq+2?= =?us-ascii?Q?dXMwebknCl5HGKOMHnEFbVyApJN/79ZxkIXndgBzU/JYYso4tWjQPcnJGRG5?= =?us-ascii?Q?NmJaMtb9I+bZIrKEnIPkESAyD7ZNLekufFDA4beB?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: da510a89-77cb-496c-d3bc-08db87a4c340 X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jul 2023 15:36:32.5358 (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: APNrwE9bMQvOurf+Zmg78gEuR29HZ62gwD/CziTzCujs4jZ0AEpQWuEVl1xc1GOw X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB8116 X-Rspamd-Queue-Id: C70D2120023 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: emc79m671iumkg43eters6sfg9zh96fo X-HE-Tag: 1689694595-337433 X-HE-Meta: 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 mb/ttJ7T fA//qMkmf6GY0R5NiVQnJcVcltkW2umTl+P4PDinyYUr46OU+6PdBvnOWKTmq6fbcvwh82P7CMHEfrWJwzNy8FXbHIqg/MxRneU9PaJnmG6vM4rJj/kJvSXt2v54TmNRPTbEp3gKUVgQwLDharlgsH+TgguAuuTYcJVTrkP45PgV+qTYuzhvafZybPIYMorvT3xLigFy/IV9ffiO1WYRzaQHS+0tMEPSRRFcC5nKkVd9QpLMGRjU6nZh9zmRxMXkS14pf 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: On Tue, Jul 18, 2023 at 01:28:56AM -0700, Vivek Kasireddy wrote: > Currently, there does not appear to be any mechanism for letting > drivers or other kernel entities know about updates made in a > mapping particularly when a new page is faulted in. Providing > notifications for such situations is really useful when using > memfds backed by ram-based filesystems such as shmem or hugetlbfs > that also allow FALLOC_FL_PUNCH_HOLE. Huh? You get an invalidate when this happens and the address becomes non-present. > More specifically, when a hole is punched in a memfd (that is > backed by shmem or hugetlbfs), a driver can register for > notifications associated with range invalidations. However, it > would also be useful to have notifications when new pages are > faulted in as a result of writes made to the mapping region that > overlaps with a previously punched hole. If there is no change to the PTEs then it is hard to see why this would be part of a mmu_notifier. Jason