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 2C3B6E7717D for ; Mon, 9 Dec 2024 10:48:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9135A8D0029; Mon, 9 Dec 2024 05:48:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8C19F6B0413; Mon, 9 Dec 2024 05:48:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 714128D0029; Mon, 9 Dec 2024 05:48:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 4E5546B0412 for ; Mon, 9 Dec 2024 05:48:03 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id D011A40110 for ; Mon, 9 Dec 2024 10:48:02 +0000 (UTC) X-FDA: 82875095394.02.BBE58D7 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf04.hostedemail.com (Postfix) with ESMTP id 9190940007 for ; Mon, 9 Dec 2024 10:47:37 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=HzewonLP; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=v9Mw9887; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf04.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1733741266; 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=jJ0y7mh1N8FLgOZG3sQP3kLvlJNQBmnqJL5T6lxaVgw=; b=QRSQ9N0Jx+8A4S3jTAYxUk0n8VgX1mArbmMkFPvRHcxj+qlgfEIrF6l8VZjuf4zgy6bUvy 5Jgnwj/EncZtXFOssnUoREqoWRw2wTY6k7NK/rCeMXkxipURnfbTSG1DUInYOQWVruqa7U 4xf5MXRYPrQ9z71Cr2eBocq+p9IZf9Q= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1733741266; a=rsa-sha256; cv=pass; b=vPJhzFucXy7V99+cn3x6wIGd+bPzJ7wKRJjjO6pEw9ZjuKv5+Cvkb7t6qdl5Pcj/Y4mZp+ vm3Rvmfr/8mQOYKmIC4F7ZqDSAOeJiu2vRj8sC5e25gEfpbNowJyPnUcGOyPQRcy+uUeoO YdnStBamKTj0tGV81+CnKoWbK3fEi+Q= ARC-Authentication-Results: i=2; imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=HzewonLP; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=v9Mw9887; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf04.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4B98fsYA011201; Mon, 9 Dec 2024 10:47:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2023-11-20; bh=jJ0y7mh1N8FLgOZG3s QP3kLvlJNQBmnqJL5T6lxaVgw=; b=HzewonLPU7JQPGlDjj2YxiesBgyWYGPxxJ uEgKX2rfG3XWtW2glmtvgx7omQTzqvh++r5TCbP1e5ALQtKYgWkyQRgO59+1SZYD p2adoySBUdWlciW0xABuF/aZE6PeQaDvSc3LDtL3NYVHsb6q/31kggyAttoGA1pT suZsBykknUGaeuVNoQQzLYe6mk0g3IPF7ru+HA/dHtI8u2jDLCJ7XarDPrm6UNOC LydOJofAT2S5SSyvSIhrf5nTv/MNcaJNFKJWDusrv/GCV43Ipgdy1U+FVh2EBZD2 3Cu1j6Qo/+mh7vIeCeQTqVHWmFHbcj5c17vUckVUjeOUCXl8j99A== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 43ccy02yre-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 09 Dec 2024 10:47:53 +0000 (GMT) Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 4B99TGQG034958; Mon, 9 Dec 2024 10:47:52 GMT Received: from nam04-dm6-obe.outbound.protection.outlook.com (mail-dm6nam04lp2044.outbound.protection.outlook.com [104.47.73.44]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 43ccte67cy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 09 Dec 2024 10:47:52 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=Bbj5fl26N7mYL7tZYx+yltoZmHGh3QLcQfrNFPFNH2VbNGQQoD2fqCA6GXcquK+vYDMDcREldVreRn2HpraJ6fC0TPAfENkJBoJ8zaM68xruAbAe38lsyJ6HpmwGXtEmBrCmxG+LfdmAd1KKeFygPUu43igwMzwh6GYNd9kARQKBcefKPoGa0nTz8c2DUeOTm+zI0caE/vTKEMtP7VqzeQOk5hmRdCjJG76Ti0ZF3U0WyvikwiSc/aKjbDkPNZk5yY3ESUGlOtqUIEJx4tQ6yZ9PAqzlZt9YEbSR1F3LutH3eadvTB/Msq/eZBs+WoVE86Zo9E9BrMx3rm/9tNnrfw== 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=jJ0y7mh1N8FLgOZG3sQP3kLvlJNQBmnqJL5T6lxaVgw=; b=kzZOUQKh6FsISsSSAYSGy8NLvRj22Xsf9b76BvNdTXO4wWDCOFELkzHlikYxwNutXBHORRwFsCKZ2AMuO8nRNH01cinc5PCM5UeTH93fs/zd+UEIikNjWhK5ctYaY/pxWbZPIR5jogIr+lXgWMAQMq38o1nKc2sYZ/vwNbXmiHiHR61qzMdZ28uHh9a8dAuuMSShuROdjJbGQQf+VTNxKfwgj13PhzjPlAsnMNsFyciOZHQrSYa5s1HGDiW4X4lOFn2CzgF4JJQ77JAEgFH+/D8AHdtPGdEA56YYp4EAmlGIYoBvrn0m/aRr6mHzs3JIn8NMLlJdu1bZIzsu9r81AA== 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=jJ0y7mh1N8FLgOZG3sQP3kLvlJNQBmnqJL5T6lxaVgw=; b=v9Mw9887DzXkqesc9vfG8Ia7PRVuoLxJiSrCxHAVFV101JUi7sEBHA7kzXqX7hqZedgP2Fwra7ki5bTL11+t2kO7RnU5pScL2nAnj1HmWof7nRcEbLI7MwQvKEAk8Oe0vxwThGgNxllzoNrTRymJ7XrY9e/AbDbiVDGQZKzu/q0= Received: from BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) by SA1PR10MB7593.namprd10.prod.outlook.com (2603:10b6:806:385::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8230.18; Mon, 9 Dec 2024 10:47:49 +0000 Received: from BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9]) by BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9%7]) with mapi id 15.20.8230.010; Mon, 9 Dec 2024 10:47:49 +0000 Date: Mon, 9 Dec 2024 10:47:46 +0000 From: Lorenzo Stoakes To: Wei Yang Cc: Andrew Morton , "Liam R . Howlett" , Vlastimil Babka , Jann Horn , Eric Biederman , Kees Cook , Alexander Viro , Christian Brauner , Jan Kara , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/5] mm: abstract get_arg_page() stack expansion and mmap read lock Message-ID: <7205d7ff-22c2-4169-a3d4-c031c09c0f3e@lucifer.local> References: <5295d1c70c58e6aa63d14be68d4e1de9fa1c8e6d.1733248985.git.lorenzo.stoakes@oracle.com> <20241205001819.derfguaft7oummr6@master> <20241208112706.cmzyrotgnjflv47h@master> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241208112706.cmzyrotgnjflv47h@master> X-ClientProxiedBy: LO4P123CA0186.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1a4::11) To BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BYAPR10MB3366:EE_|SA1PR10MB7593:EE_ X-MS-Office365-Filtering-Correlation-Id: f9d5599c-0c14-4eb9-52a8-08dd183eec95 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?oW+GR1vjYdOKe067RHcjzPMHYdjjTBvRBbtNnxpER4YiVi3aNgdGgpyhVH8b?= =?us-ascii?Q?TDprfiOm5bXorFVLIRNahspLiHraX85v92hpTe7zzbYI2RiQ3Qbr+z4QT3Mr?= =?us-ascii?Q?h45A3KJ1w7yCZ/Knt7+K/cimdFkodrggXGV3CPkqIvsWV96aeqpoxqH6fDv9?= =?us-ascii?Q?5uYfdOQ7PuZpFiy0KEwgcGgvIKncGJrI0BNqYnvzeF97q3zebG8Z2LbSouIo?= =?us-ascii?Q?AGVO3QPOjg7i1AUKbXkfrIq7SG/aA+Ye7MczwMV1A+fmLDyk4VqvW49ezN6N?= =?us-ascii?Q?fmjndQtlf54jJPjb+VMCZfLAhrX7SLMwJ2ND4rroimFw8R5F5ZVCWjrftNdW?= =?us-ascii?Q?LAz3JQqwnwzUG0C0DjzQdeDDUgJgP7Gu4E2ds4soLy2mLPdy7f6G2nKfttjY?= =?us-ascii?Q?Fis7Ll6ShgsWy8v2R2HBfa06f2tm/gmPCF2mFPjiG4CzTH/MKUStK1RLVQTj?= =?us-ascii?Q?WDS6WYMQJ28ZJL9qsjlUGkFDo/NLjRXZzoM4p1yQWZsozv/ortzX3HcCpXSz?= =?us-ascii?Q?Pb/D1GNjNu7fAU+VPGv19/nU+YkLzzGb2dnmgbIGwj6oHtrobYYl5It93kte?= =?us-ascii?Q?2HyHW8o5ZIUeRftl0I/cxanzB0lccr0HLBrQoBAOmJxmkBk9T0a7UOXcdxvN?= =?us-ascii?Q?jLXcg0u+nTWw4AxNZHnHYWYmqNYnHZT9s+RXE6/7Di+PXXzrv4XmwixdyuLq?= =?us-ascii?Q?66mLefCYzklnroYRYrZtq1AAwyky9JD+BncfP2bBdzlRl/WahOpTkhetzgH2?= =?us-ascii?Q?xSrsZcxR3ClYJEs/XXrw3DbGrt0yJa97Xgt7Cs11l8LgZ5z1jI3sKHs8hgQE?= =?us-ascii?Q?rmRWHCPPrxXhrInzlZ5QNJZ8OgkwO2DCoTG5AdQynKmDtj9oZx7sGm5HQ18w?= =?us-ascii?Q?zuAmbe8OpjR9bQyaOj1cQ+ziLbK3okAOMmnGzAhiF3ww8hw7CNAUi0Erigkl?= =?us-ascii?Q?y0TxT8ctCVehZHu5XCntiessoQfoFXzzdl9phkWolq1ECaR3MFKAIiLb6D1p?= =?us-ascii?Q?N/E34mpToQIW0JBM98fDSQLO9yGysyCN1U4G1EFmWp1eK4pAD0Vp+71p7jMD?= =?us-ascii?Q?AEOx5GVnWvP8Ah0a4gVfXbMs69a7uwnuccMezmh1KIra28CXk3IK8naihwSF?= =?us-ascii?Q?6OshQnUvBJD/X+meK79gwPt8svHXQ+GlKtxiZVnxIsPOEtIV6Yov+47H+AUD?= =?us-ascii?Q?RqBqGm13OZ70/gonJcrxPLtY43ZX+cdmz8PSh6TxRZi+0CNe56V+J/icPWUJ?= =?us-ascii?Q?zVtHV2XNggySnLKdC3hpnSuhTPnkalGIOCm8y74KBQHlYl5Cx9QhOgHu5nx5?= =?us-ascii?Q?Bo6QM7vC5Ge4YeWHlZMSV6l5yBiNBYhb3SVTb0TI5Jli9MZT3mRrckNFpGg/?= =?us-ascii?Q?JRjE6pg=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR10MB3366.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?LxXtzJinIPkbE1ZhjPb2zwQ2aZdLBAuhLJZ5kl89+fZQq6hTenJmDgy7n2sA?= =?us-ascii?Q?a5hD/51aTJVXHuXSzxNPc6ZwNpsflGiEYnGAA02eVxA9IDXBgB4knoQW0HZF?= =?us-ascii?Q?t+jqRTjouWMRx61WgbGYLzJSLIxu5YqGXK4FpDzniY5EyZ9311LxNEvsnuso?= =?us-ascii?Q?zK+GyoQw1kGRauPvsb6W+xMYqbkhnHpjNu4DD8jjoXt76jQiqM9vz/2uxIO5?= =?us-ascii?Q?PPdVlYFNXyg7mcSGCOoTCIRnFvb8q34QAJtnxLnbLrynva6Qjo3M66IdhDio?= =?us-ascii?Q?ncWAkuDEwWAbptD4+S/krpKcyZ/x/sfp+7mUNQsgbMFPKDZ0kLN8XDRluAJn?= =?us-ascii?Q?xuFOvYHpPg9/J4bdHz/Usn4wux86cNWbrkW3XFMQM8hjmDG1MsO3/B9lUkZA?= =?us-ascii?Q?as7+LA8Gb1TN9sA2tCua2+46KtQ+vIXX/qyt2RoisnlyFx3PTgHKyoA3lSR/?= =?us-ascii?Q?gqHa4V/KKN4IKWIJeWaw4FQWGUWg9sF+4AxhBWZTyUJge9arbz4M0Hrlgo47?= =?us-ascii?Q?NT2i1aMRuMNILQ85Gg8/8KJRk/7Rtd5CfVGhc+3A/YtaaHcJURxXColMMoPQ?= =?us-ascii?Q?y7wQAmknrEYo7JoyUg2HWCQ9CgDW3G6KR9aD/+gbu1QSLUH4byx1xRMTmr5W?= =?us-ascii?Q?7pzvAvHMrFu106tGlYjdy7VKBITaOvEw29yRyjIyFTYOnWbyW8LdF2y04hkk?= =?us-ascii?Q?enm6qvA7DirDJMwtIEQqsrX6xLuZLqOlFVO+w8O2h9jtXa2XDJx0S3fMgn06?= =?us-ascii?Q?ERnz6mQ2OU2VOJW/psYIAyuOX/+JzrrSxQrWV7xngj6oRu5wjEBcswzVTXtA?= =?us-ascii?Q?v/7W8fAN7lFVnzuj2RI9iv5htqSvHjARrGcZfbgo9Xi/zjoguA+P2I+euBka?= =?us-ascii?Q?tO/0d3gxlq5ZhF0UUTLdQQam3vayDK+GQ03Jlw1qMZcDsf5CCLR1Cd4JHpZv?= =?us-ascii?Q?dqt+sEj9vtIYV0doTv7jWk8+OUNcGCIBhx+xEIOCtvsZ+gXMEGQQnJJznIEV?= =?us-ascii?Q?V7WxNcDfz2MFx132oqGzt33v9/84Od8NHSt9Dl13D0gC+Xp1rmEburTgjFer?= =?us-ascii?Q?f2EV+gA8GKe/iUftpnlD0ps3fEcRErAffBI4p6CIM72K6m3FpUHtBgLPnt84?= =?us-ascii?Q?+7+kZpF0c1XsEHO+s+lGtVCV2yDFXyHvkBSvnFgfVWn6qj4V9OhMqtTMTHB3?= =?us-ascii?Q?iHonwRKC87ITrdev4eM4P/2i5Yj93vwrhfkzi08P/IYnNJ1m9qLIGOT013Kp?= =?us-ascii?Q?5Up2Rnl4PX7iw4HPAS35iSMwPE5TtsJ6zUmP1HXGeSbqOcnerV9Ac9JVC2Ed?= =?us-ascii?Q?RHxt8oRtjZeTolOTnKs81bhHlY0v6Ja1Jc8rnE6oTDgUhou61Po3eQnty330?= =?us-ascii?Q?txctuFRA9z0feiqQc22/y5ixAKdXCUe9rtVJ4Ix5rwsRY0T+Fod9dLT2U+i5?= =?us-ascii?Q?Ov3lfShmHnxJ5Ro2FdAYyO/XNWPHc50GUPmxourR30D8Efm/a7CQ9CT2jIBD?= =?us-ascii?Q?rbpwaq+35zRyh+WviTEUQaaDdjqrUqXigqZBr7WBr503h0l+9CX+pbXiDRLV?= =?us-ascii?Q?v0IDcUrFp2A9xsaJ7uLxHkaMY2ObesEWz9eUVpcO+XC/u9Rg2Bk/eo9PYRRm?= =?us-ascii?Q?tw=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: f9d5599c-0c14-4eb9-52a8-08dd183eec95 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB3366.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Dec 2024 10:47:49.5554 (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: fPE3CgmiM1rmYLJc9AJP8XN70W79P39FdqYumeqfzFN6DtHyHnMGf54WPoek8cvLrKj8QVwvEU9fB4vyuq48z5/XcntthztnspkZ9/NcFO8= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR10MB7593 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2024-12-09_08,2024-12-09_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=950 adultscore=0 phishscore=0 malwarescore=0 suspectscore=0 spamscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2411120000 definitions=main-2412090084 X-Proofpoint-GUID: lZgTHN-_XuFCwLcbICi_62CcMscpkavH X-Proofpoint-ORIG-GUID: lZgTHN-_XuFCwLcbICi_62CcMscpkavH X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9190940007 X-Stat-Signature: fftfekwrnpup79iuti5ig8nmpm9iab55 X-Rspam-User: X-HE-Tag: 1733741257-604179 X-HE-Meta: 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 FzOr1iGy 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.010439, 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 Sun, Dec 08, 2024 at 11:27:06AM +0000, Wei Yang wrote: > On Thu, Dec 05, 2024 at 07:01:14AM +0000, Lorenzo Stoakes wrote: > [...] > >> > >> Maybe we just leave this done in one place is enough? > > > >Wei, I feel like I have repeated myself about 'mathematically smallest > >code' rather too many times at this stage. Doing an unsolicited drive-by > >review applying this concept, which I have roundly and clearly rejected, is > >not appreciated. > > > > Hi, Lorenzo > > I would apologize for introducing this un-pleasant mail. Would be more > thoughtful next time. It wasn't unpleasant, don't worry! :) I'm just trying to be as clear as I can about this so as to avoid you spending time on things that aren't useful. On occasion I think, for clarity, it's important to be firm - otherwise if I were receptive even on things that I thought not worthwhile - you'd end up wasting your time doing work that might end up not being used. > > >At any rate, we are checking this _before the mmap lock is acquired_. It is > >also self-documenting. > > > >Please try to take on board the point that there are many factors when it > >comes to writing kernel code, aversion to possibly generated branches being > >only one of them. > > > > Thanks for this suggestion. > > I am trying to be as professional as you are. In case you have other > suggestions, they are welcome. Thanks, what I would say is that simply observing that we might duplicate some logic in a non-harmful way does not necessarily indicate that this should be changed. Obviously if you can evidence a _statistically significant_ performance impact then OF COURSE you should report something like this and send a patch for it (along side the evidence of the perf regression). But in general, if you feel the need to refactor just for the sake of eliminating branches or grouping code like this, it isn't helpful or useful. Refactorings can be very useful _in general_ (I have done a lot of work on things like this myself obviously), but it's important to assess the RoI - is the churn worth the benefit - does it make significant enough of an impact - and is it 'tasteful'? These things are at least somewhat subjective obviously. What I would suggest you focus on instead is in finding bugs - your help in finding the bug where I (ugh) set a pointer to an error value in a case where, if you were unlucky, it might be dereferenced - was a really helpful contribution, as you can tell from how quickly we approved it and arranged for backporting. I'd say this ought to be your focus. For instance [0] was a horrid mistake on my part, and ripe for being discovered. Having a second pair of eyes checking for this kind of thing would be very useful, and discovering this kind of bug as early as possible would be hugely valued. So yeah TL;DR my advice is at the moment - focus on finding bugs above all else :) Cheers, Lorenzo [0]:https://lore.kernel.org/linux-mm/20241206215229.244413-1-lorenzo.stoakes@oracle.com/ > > > -- > Wei Yang > Help you, Help me