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 EE641C3ABDD for ; Sat, 17 May 2025 19:29:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4A88A6B0082; Sat, 17 May 2025 15:29:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 457B26B0083; Sat, 17 May 2025 15:29:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 283146B0085; Sat, 17 May 2025 15:29:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id F0CEE6B0082 for ; Sat, 17 May 2025 15:29:00 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 96A20BEB13 for ; Sat, 17 May 2025 19:29:02 +0000 (UTC) X-FDA: 83453387724.27.716F23C Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf25.hostedemail.com (Postfix) with ESMTP id 1FD93A0008 for ; Sat, 17 May 2025 19:28:58 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=hQNT4pGc; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=wM4fJUpH; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=temperror (imf25.hostedemail.com: error in processing during lookup of lorenzo.stoakes@oracle.com: DNS error) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1747510139; a=rsa-sha256; cv=pass; b=FPhXexgEBfpnW2V7vSL9GLeNJx466vzmAUCfm6H8NdxgFUPYGOAyd2Z0gee6rKQMlj2KZY cC29GNKECoOnoSepIl173a3wASGwde1xMz+n3WqpEWnLws0bBouq8YGOzyjy6chiAm89f0 USexaGfD01qRBTAyxwSz5MiMiEeYCQA= ARC-Authentication-Results: i=2; imf25.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=hQNT4pGc; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=wM4fJUpH; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=temperror (imf25.hostedemail.com: error in processing during lookup of lorenzo.stoakes@oracle.com: DNS error) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1747510139; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FcvGMD1lpoZEjyiALZK84albI/IvyQBc3eCgcxjGIvQ=; b=OSHdhEglFnK/Xx473zPIK517QoaQC1Mk9xcSzB4tnVOqQy4ynNVs7B5o1qIdGSuzQOFjJN ljpyrpA2OfpCiHYXx2IRHDaTUWEuNqlVl93YSyEpuq6UloD6SZsoVxLpJSyovVHVSasKSC 4SNwHua1VmWtJdEO2Tzq6HEikUFe1KI= Received: from pps.filterd (m0246631.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 54HF5b4f003913; Sat, 17 May 2025 19:28:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h= content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2025-04-25; bh=FcvGMD1lpoZEjyiALZ K84albI/IvyQBc3eCgcxjGIvQ=; b=hQNT4pGcCiUyM2WY/1Z5EXgISUz9cMHu3F sqaSB67fDRLMN2Ai3/np621MvmETLes0gHWveKJaiQj/IhF5azNNtd8JPfSSF6/L g87W2ZbCpOvKwAIFmUymKWYncfFrOrr6el+uidE00UtBDXzZ85K+JzufGPXe2ki8 dC5N+FNdZDcmGqc1ERlDOKw9Z/jvFAY2zKYPyxdd+DCGKp+tcFm2DBvOTOGYFz09 6dCYsWnNcYDS/2tDBldSbFDdxz0fdMAteaXy5iSh/cwRfihRWGnO5TUikjawePg9 u3lX5xRTNKNW3x3dvTsrslPV0SA6PslG1V2F0xK4iab1Wo57l20A== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 46ph84gjyg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 17 May 2025 19:28:55 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 54HI0IRp010840; Sat, 17 May 2025 19:28:54 GMT Received: from nam12-mw2-obe.outbound.protection.outlook.com (mail-mw2nam12lp2041.outbound.protection.outlook.com [104.47.66.41]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 46pgw5dsqx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 17 May 2025 19:28:54 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=hUv+6m43qxUdrklrGMA2KoCJG7mY0Gqhdl0bFkrhUIsQKgIgP78m/3xvBGpkLYi/ld9509zlSnphA8+Bh5Q9RaCmTVIF4MgRkF6g/oDj0MqzDyRj3J6dy9ixSn1xfEkjnXKfuBbuUEx/5L3mXQaRbeCZpbtKY3gvc8T73tKMguddEsuKkevNql5puT90fxz/pAOE2iLgj2Q6l9lNQSnO3lW9hlvax8Kd1dDsk7XKf91vdQncxfF8UMEJsOhbKEISRzgR4Ly9+Cqn7sy+ATJf/VmcVYq4m+Zha/cBCMuPEEdMxacLIhcds1iNbKujmN9Rtr8nzQDbyWQzFdYXvn1rmQ== 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=FcvGMD1lpoZEjyiALZK84albI/IvyQBc3eCgcxjGIvQ=; b=RSxEbMyqf31z04F8dV9b4YLtPeEQdQdUpLPFxo3JZRGNfRvogy8Vy/PwV+0DzgOOJk43BJVH58AvPNtdg4Fx1U8m88kj901nNReMvWPb0Mh4WDpiIysRnRgtO1RugxHNyQ2CfvZyvJ5SufsCCEWqZ2Ilz6I+SCM1RDtghrUdStVsu5BjyWzkwzGpscDIdumYJho1sBBEKdUBDoUC3Ax6ScxVIViVG6WLb/mY+D7zNPU8+9WWmjanrDRzlVw5S7k4NPU4h53sbQZ0g5J/V5brscqb0WhKpeaU3OQZRd+U2Uvsip0EBifjZucTw/Oitxmz2aCMkQaixuaezYZ6eCWsNA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=FcvGMD1lpoZEjyiALZK84albI/IvyQBc3eCgcxjGIvQ=; b=wM4fJUpH16G3MsZm88tJi1dbhYQrmHmRapIPlwojGho+1ZcYRz4bzqpDiSXDr3cbNTirEJXACWsJvFvW/0AZ2DbmAs7KntcC+l8439OgdnsKiXuAPqiU94rrKIy4E6TULuifQy1p4pWqN7x1zFjzB9zP64HYWkbyX5MHK03MqgI= Received: from DM4PR10MB8218.namprd10.prod.outlook.com (2603:10b6:8:1cc::16) by CH2PR10MB4215.namprd10.prod.outlook.com (2603:10b6:610:7e::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8722.33; Sat, 17 May 2025 19:28:51 +0000 Received: from DM4PR10MB8218.namprd10.prod.outlook.com ([fe80::2650:55cf:2816:5f2]) by DM4PR10MB8218.namprd10.prod.outlook.com ([fe80::2650:55cf:2816:5f2%6]) with mapi id 15.20.8699.022; Sat, 17 May 2025 19:28:51 +0000 Date: Sat, 17 May 2025 20:28:49 +0100 From: Lorenzo Stoakes To: "Liam R. Howlett" , Davidlohr Bueso , SeongJae Park , Andrew Morton , David Hildenbrand , Shakeel Butt , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v2 4/4] mm/madvise: remove redundant mmap_lock operations from process_madvise() Message-ID: <371ec2c6-01d9-4deb-a234-aacad94680c5@lucifer.local> References: <20250117013058.1843-1-sj@kernel.org> <20250117013058.1843-5-sj@kernel.org> <20250131173132.uqjwrzj7e5vx2sbv@offworld> <7k2gs6xmx2q7la6kle5xpn2p2f6bccbiv5lrdowp5hnecxpijx@rzwxdhcl6mc2> <5fc4e100-70d3-44c1-99f7-f8a5a6a0ba65@lucifer.local> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5fc4e100-70d3-44c1-99f7-f8a5a6a0ba65@lucifer.local> X-ClientProxiedBy: LO4P265CA0179.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:311::7) To DM4PR10MB8218.namprd10.prod.outlook.com (2603:10b6:8:1cc::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR10MB8218:EE_|CH2PR10MB4215:EE_ X-MS-Office365-Filtering-Correlation-Id: 96160026-b884-4107-67ed-08dd95790e00 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?3Bvxy0OV8LrONpusbYnhXwMs8OS/49DMPTKfwtNSHapQsDYAjodKX+BRqBis?= =?us-ascii?Q?82UzBp2JGMbDKdbUWZRSP/8HCWlFfYkdq2ZMgQ8pT6onrH/ZFYiYuVVpIYVc?= =?us-ascii?Q?XCR5pV1EarkpNRx6DvudU0wBePVlbjd+xcywZE1I0Rtgv8A9Z5iX0jBS8U/t?= =?us-ascii?Q?Dp+plivm2kvGBWWDYPTKxzF0pMA1x0Rs8wGtPDoE+A5IZedGoxIdxPi0P6AF?= =?us-ascii?Q?RP4qxbTxpynvNL2JzJbEnXTCop5AFgkIBRR7G2QKBAUY+igkVcZ0fFKPA8sk?= =?us-ascii?Q?T0f1HArXCOEsIrpKmZz5IffcSf+h+0TIjqcKaVYGewX6YpGT44GETFxnH0qU?= =?us-ascii?Q?3qpaLnwbkDyWbYuQecM2k8Q406iIzYvEviGHSA0s+SDHm5j8KzRDS5qkqB7g?= =?us-ascii?Q?JZUFyeUlGccoR4aF1hX4TcSw20ke+YxOEwcz5ZrX+oW6+J5QgeNuLRkpO+So?= =?us-ascii?Q?eKh8s3wV8Yn6Zvyrq/+wfbPhOTVrkPbbJXerKxVxilUaFqhCpRd5VHLUsyx6?= =?us-ascii?Q?soiBmqQoQJfhg2HMdMF9GDiwutiUBn0peJl60RglFLFGz9/GohtE/HUvTXI6?= =?us-ascii?Q?KO7YTTUHEvgSbH8r973BWKWmeDcE5DRN3+bZJGYlFk4F+A0COHijaca45jIx?= =?us-ascii?Q?KJorllYrERveM8YmGMg9WpbU0UU2czNfuEEmjHp6flzIQts2ITYURZUiW3vh?= =?us-ascii?Q?DdcCMKNpkvH9cmNttQAB0FIR4RVCMo9OffDiNhfZrWUWufOk1UzNvCQfIKQz?= =?us-ascii?Q?A1pMkU/TSirI0/mUphKHjHBDRDiaq/3CqOSOx8aIp3rkSKDziSkmlLYFkMuN?= =?us-ascii?Q?XvkX6xpMejnGsj8BkcTLB6MTTAVVQrkZXC/JC3UVEwT8F5zoMpArzIBW9Jhp?= =?us-ascii?Q?HiW5z+P4xPF8t0BUNXseveZhgLoYCz5tQdAjEeZnB6lqMbVbg8NE8o3i0+15?= =?us-ascii?Q?VlUkbEVMVIHLVggEC7T89ztjNVYV//gtgayVD9sTqExczjNDDzguBNFOMxc6?= =?us-ascii?Q?YHQYGTbqGJc6B6OaxnHEuUoTDBqx9n0xZC7lS2+bDp/84JQpXIeMt2ZdXQFR?= =?us-ascii?Q?qZQp7f8XAqde+y9fhENXxijIdHiaQ7sAEnK2LaLZCOmkwXfChcyPu3fNr9SO?= =?us-ascii?Q?kBOO/Egrt52WpQ5yF64nFNJ66OLvLc5EqtKayT2wwUHOBQvEiRViwPQ5hwUm?= =?us-ascii?Q?74W7oRg3CU92be328eJCSEdmXP6yPChQS5vLtxFciACK3A1lKhc7zTcRt/tC?= =?us-ascii?Q?P+fRAO1o3PgN8qw+5gpOvwef5NrFWRmkrGkm3NnTDHRIeWHbMfWM15ylB2Sq?= =?us-ascii?Q?OOaw3l+LMBbCRibHuOOFKNP/NSTjUNLJMRRuZrIV02NVj1FdzQ7K9sfSl7gS?= =?us-ascii?Q?fbqlm3nf6wY8G2WmWVU+PZTWuwlOcU9D/zhPA9SupvRMoeAVpUn0VaeSYUUD?= =?us-ascii?Q?tofLmgZB9XE=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR10MB8218.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?/qpGRSigF6o0gXNaUaaveecsHULzVZ9J3SShwhSbBQ+m/xI9vF3eoN8CWZDk?= =?us-ascii?Q?aoPfO6BGePtNiI8vggbk2k6ybPwZq2OnnDVbjrzezJc3uTrDTa2m1akuY9yJ?= =?us-ascii?Q?IMgCBrmItPI8BlHeOK5BUzrfKxnfmlhMJ0D7YKGM7XHv5IgKxG8D+KlewhLb?= =?us-ascii?Q?/Kj67IeDa6RDPgaM3g+CBQCK2EtHwM5qGZ0ajUa5W+kGX/LWyTuZ++9Uk668?= =?us-ascii?Q?R0XNjTjqk/BR5ho8Eg0epkuiq9O9B0d9odPB6JP5ObCZ0sXx9UdbrwJNJLRB?= =?us-ascii?Q?VY+gB3WITYV2VPrHRGPKRkudVBNwhtwn73h2KkTW/yZu7hI6Z5WXePaocBZg?= =?us-ascii?Q?UIARdg3oiWolSaOKLNdfJd4K56JrB2cjCyVlRJQtET5o7RoJcE9/ZLIAtSd5?= =?us-ascii?Q?DxzBvtRR52jkkklq/dkdlEK5LaE+9i6XNTWstHQ6O3WaQG3L9fcwC26khfs1?= =?us-ascii?Q?9xCiqRzjXcgyTfiPmubea2pre03lDxFd10CLVQ5C0Hy4WqSJvdEKv7C16J1A?= =?us-ascii?Q?+klcBu5WCoJHqJC+T3u/p/nIFP4P//A8mf6xFCmgikvLQZ7sVpIDNdicvVgf?= =?us-ascii?Q?zgAW9zTjh43UVL24n3F9ajTD2Ou56MnweqkxKvc92saPmbbgEuvpcoxZSEaY?= =?us-ascii?Q?d/pC6DzGQI0mvsdQv6MdgbgpNuKz0tZtH9bXF0dqf7Dy+7SPTDo3dOBkE1v5?= =?us-ascii?Q?S6SsxIDAXabdQFeguh/0szMYolkjrYPO6MH0HnnNRKSxKgg+N5Ou7Z7XmPxP?= =?us-ascii?Q?V7iT/QQ8GaNGXrkeBV6ipDYTFOduBfBfZe2nXLTcZnYydtH0OW7rA6T3+MwU?= =?us-ascii?Q?rIZel1k7yj4yWDDmwDvoRCwiT5bDg1OacBJClwilzvlLmC5O33UXke2tsxGW?= =?us-ascii?Q?/fxC9kZga2/jqolxflgaRy3nv2slP0F67J0emiM9DaHC9zYTL2zxQ6vhCs9H?= =?us-ascii?Q?3zl136/6lClHhD3YWk7+FdJQn2jfV8IDr+rcsNRQSIWli+u6qSaSp8TXhcP5?= =?us-ascii?Q?X/8CLOe9pvuuZrSp+7R+XyCRdZuuSkcqrljaWt6aqQ1kCi/Rm7pCnO/ZgKxB?= =?us-ascii?Q?yc9dSMDx/KTgp6qC+N3R9ovSf673vpEOShBGPgu2TYeCafeHW//tX6yegXNy?= =?us-ascii?Q?tcuFHgP6z6NAN0qF2MzcxCkb/9z1sGt3m4Pck4wM9sEzqfNz9Gaj6IfBWPKB?= =?us-ascii?Q?2XraHzGxGw93d4iytd3LL8FD0eYYVl3MQpo/BVw0B7tJyMyyub6ospNbB5SZ?= =?us-ascii?Q?n9WZDtHpuD71LIGgrgiHwIUZh/Je/fu7L2AD3eUYiutRv310r5RwcKrE+zBu?= =?us-ascii?Q?iQ14e1vKGuP5QH1p583WLiURQCRL3g+70dHoXRjLtqUCDri0ZYIBr2HJBMpH?= =?us-ascii?Q?vHB6JIRUk7mIuIXegMNbEjQWALJMHBOLle+GqXRBpTkJJV9LmKLi0rHwhDtK?= =?us-ascii?Q?YS7CagYMkLrGjCpckGA+8/4L/jIOKf23HTrZeCNC6yKGle313ynMuGJMt1In?= =?us-ascii?Q?Dvu6YOVqlgPX5ysuIzyVGrWOVb1/YGpESCbpGZ7Tlg2jRCP3+Kb5c7wta7JG?= =?us-ascii?Q?dG1mNdlRj+e8AgQjALZG3fNIrSIB7FRfPuZbJmasELKoFRG/ynCvxdUk6lJ7?= =?us-ascii?Q?1w=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 96160026-b884-4107-67ed-08dd95790e00 X-MS-Exchange-CrossTenant-AuthSource: DM4PR10MB8218.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 May 2025 19:28:51.5985 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 64X1Ha77LO1rg599YMo4Sc7/Hhl/c/PkIp7X4KXOyIiLHdwxgn6O6A+Kw40PP+QmcQQnzg5O0F7vwIwv5CXLbZ4KXYHyfE1osJ4SBLvKyw8= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR10MB4215 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-17_09,2025-05-16_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 malwarescore=0 phishscore=0 bulkscore=0 adultscore=0 mlxscore=0 suspectscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505070000 definitions=main-2505170193 X-Proofpoint-GUID: Eyv3jLvBcIuVsJeS8kt1PZNj9NmxOc5w X-Authority-Analysis: v=2.4 cv=YPSfyQGx c=1 sm=1 tr=0 ts=6828e377 b=1 cx=c_pps a=e1sVV491RgrpLwSTMOnk8w==:117 a=e1sVV491RgrpLwSTMOnk8w==:17 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=dt9VzEwgFbYA:10 a=GoEa3M9JfhUA:10 a=VwQbUJbxAAAA:8 a=R4ayLD03AAAA:8 a=vFUq353A2xUveRRD8ZoA:9 a=CjuIK1q_8ugA:10 a=qJlm0-shE6CLU_iKUWNr:22 cc=ntf awl=host:14694 X-Proofpoint-ORIG-GUID: Eyv3jLvBcIuVsJeS8kt1PZNj9NmxOc5w X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTE3MDE5MyBTYWx0ZWRfX3IH9/LksxrAp KeCwTxMEXDfWvHumYmOK/7De1o0egc8XmkO2wWTF+RqbmOez4rrlMS46k46ioLL+LOH7JLJ0gqs zFMrZija7ymI69eytbT5nostOQbAR0f1KVBV0nesm0qFq8JYgxBRbJluQJHPNA6n7wZuehUvF8c F9Jt7U5qGnoV1Wmw4GnVsqjcEfCjLAg/1/cW5w3GCIaMv4zAVoKOHtPnvwDS1O5Nk+cqm1HmNmj koWtdW8+xEIAQaiw3h6Y8bqhfLMGLZscXb4ZzcgTAHEKnqM1exGmj0vVgY0eOM0Cl4muoZu/omB rx6sUScMZOSKIebAnGPY8r+bWsJyMWL5bunRpFJjeKkUf453Vjjy0ziRJeka2p+GrXFgw9DF6QS 6z8WsV/sygdihB9yS6UH1O3LtzSF1W+QCK0vSGKDv1G2Q/IwArLyY9pyI9JWdt0Np4GnRTFn X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 1FD93A0008 X-Stat-Signature: xifqb1ie8nn8sm8nohce3y5qhesa73b9 X-HE-Tag: 1747510138-591842 X-HE-Meta: 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 2mtafja5 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 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 31, 2025 at 05:51:45PM +0000, Lorenzo Stoakes wrote: > On Fri, Jan 31, 2025 at 12:47:24PM -0500, Liam R. Howlett wrote: > > * Davidlohr Bueso [250131 12:31]: > > > On Fri, 31 Jan 2025, Lorenzo Stoakes wrote: > > > > > > > On Thu, Jan 16, 2025 at 05:30:58PM -0800, SeongJae Park wrote: > > > > > Optimize redundant mmap lock operations from process_madvise() by > > > > > directly doing the mmap locking first, and then the remaining works for > > > > > all ranges in the loop. > > > > > > > > > > Signed-off-by: SeongJae Park > > > > > > > > I wonder if this might increase lock contention because now all of the > > > > vector operations will hold the relevant mm lock without releasing after > > > > each operation? > > > > > > That was exactly my concern. While afaict the numbers presented in v1 > > > are quite nice, this is ultimately a micro-benchmark, where no other > > > unrelated threads are impacted by these new hold times. > > > > Indeed, I was also concerned about this scenario. > > > > But this method does have the added advantage of keeping the vma space > > in the same state as it was expected during the initial call - although > > the race does still exist on looking vs acting on the data. This would > > just remove the intermediate changes. > > > > > > > > > Probably it's ok given limited size of iov, but maybe in future we'd want > > > > to set a limit on the ranges before we drop/reacquire lock? > > > > > > imo, this should best be done in the same patch/series. Maybe extend > > > the benchmark to use IOV_MAX and find a sweet spot? > > > > Are you worried this is over-engineering for a problem that may never be > > an issue, or is there a particular usecase you have in mind? > > > > It is probably worth investigating, and maybe a potential usecase would > > help with the targeted sweet spot? > > > > Keep in mind process_madvise() is not limited by IOV_MAX, which can be rather > high, but rather UIO_FASTIOV, which is limited to 8 entries. > > (Some have been surprised by this limitation...!) Surprised, perhaps because I was wrong about this :) Apologies for that. SJ raised this in [0] and the non-RFC version of this series is over at [1]. [0]: https://lore.kernel.org/all/20250517162048.36347-1-sj@kernel.org/ [1]: https://lore.kernel.org/all/20250206061517.2958-1-sj@kernel.org/ We should revisit this and determine whether the drop/reacquire lock is required, perhaps doing some experiments around heavy operations using UIO_MAXIOV entries? SJ - could you take a look at this please? > > So I think at this point scaling isn't a huge issue, I raise it because in > future we may want to increase this limit, at which point we should think about > it, which is why I sort of hand-waved it away a bit. Again as I said here, I suspect _probably_ this won't be too much of an issue - but it is absolutely one we need to address. > > > Thanks, > > Liam > > Cheers, Lorenzo