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 C3DB1C282EC for ; Sat, 8 Mar 2025 18:16:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AAF936B0085; Sat, 8 Mar 2025 13:16:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A5FB86B0088; Sat, 8 Mar 2025 13:16:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B2666B0089; Sat, 8 Mar 2025 13:16:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 654CC6B0085 for ; Sat, 8 Mar 2025 13:16:12 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 753691CCDE1 for ; Sat, 8 Mar 2025 18:16:13 +0000 (UTC) X-FDA: 83199188226.18.7B36439 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf27.hostedemail.com (Postfix) with ESMTP id 36BCD40007 for ; Sat, 8 Mar 2025 18:16:10 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=bYckMyXs; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=wgdnfOkE; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf27.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 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=1741457770; 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=CvcJZ6DYdnwZYZXrSSXSTcQt1Ki1RAvt0TsNQwot/OA=; b=nRT42cWGyY0UEXANlatzVQgYHvfbNCbubo7EluEjJq/asutULGE2aFKE5/qCdJQbyaHny1 HNi35gt9XqFZzcVbkQu5znozDi3EkJp2Vp2YXcO2fFUOyUQmA8OPVoByDSPQR+J6LhuAkS mCY1d2ewOJPpQ2t9RYmIN8O8k7WqKas= ARC-Authentication-Results: i=2; imf27.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=bYckMyXs; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=wgdnfOkE; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf27.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1741457770; a=rsa-sha256; cv=pass; b=gtnsNTc2uQnWebBg+OoK33KY+TDaODRJyBS8UurEe/ADfJEUJpkAim5vivuVTEcucY2uZk 5qmk6VthCc+beUO3dOSNWtUe5+lBG1XCivxQCiqstF60dpgqSVJVe/VoDX5ltWG0/n5JJB LtieeAIglfZklg6BOM2SJWGKm6wDqSw= Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 528FVVZt009595; Sat, 8 Mar 2025 18:16:09 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=CvcJZ6DYdnwZYZXrSS XSTcQt1Ki1RAvt0TsNQwot/OA=; b=bYckMyXsbOnf9QwZ0kuEIpZVZsqTwS3fFK jkD9pzavA7lLbRJZ0lFGXIZyv0DnPut3JNfA8OGTWa4B09tDPBZjQSFVIY0aj5Gf 30C2bE1A41zlfPXFoglgmCrAcS9nDB2tkQJCqGEPNIrJKNGv55Iykavm9hf1wmlR Srzfkz8QrT4AcGTzzpTTykQ1aZfXoyzIQ2WcKgETh1dSNPXU99EWeCRiG6joHp+S dEKh3TLmNlbP/SmY2sN5Jza2ui6nJ39u1yoCVQFR4fLQDqGR5vQaQy/o5OUKurOA IfN7lPpfuX4kyVi67/VeEZTZarTYHVxnJMeASZi7OE18qsGTaeIA== Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.appoci.oracle.com [147.154.114.232]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 458dxcge90-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 08 Mar 2025 18:16:08 +0000 (GMT) Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 528GcRqW026288; Sat, 8 Mar 2025 18:16:08 GMT Received: from nam12-bn8-obe.outbound.protection.outlook.com (mail-bn8nam12lp2172.outbound.protection.outlook.com [104.47.55.172]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 458cb66red-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 08 Mar 2025 18:16:07 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BvsZr8qN1rZfjUb3pbegvo6PopWu0j5pVmADQuBdHpyWDPZ+cZPPAJ0Rk+w8baN9Zwnkj/hlYsno7GUvGMFCLQvLgruw2LvLiHjyHeFJVt4Fn96fHHeJX9RP1ZQ0xYgH9Epu3zyb5C+5vLEQhvslZ6yOts1n6vWgcRH8Y3vpuSQA9k/AOnJipl9KZvUOk+D93dJroOdXhxP7KEiYc3EkLo7YAmn7nbcuRzsBWS8Sx7MsmDF+imWDDML8z9EK65BVMFE+ZyGODpUsazHifJeghB/5lZykPjnW3vXk20EBpBz4HadendI6U+rGUcCzNAWbEpWMv2gZ1ubBH3ulo3WJgw== 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=CvcJZ6DYdnwZYZXrSSXSTcQt1Ki1RAvt0TsNQwot/OA=; b=iS6J9KCe9QB9dmsua029peZR5vAt96PwRsoNSQTN5iPPkCaWlwQ6bU6pNuLtsqCwTyEV4+4t+2gn1t7ksUsWo8dpDnNJ+IkRXfFJKFrtXvZ2+/EMRTav/19DuNwBomstfpyIEdM4PFquMe6xmEkVQwvQ8X7gD5wimjbr+g5+I8sEHQmssnymBsFSm+LIurCJk2Nd8ID2zTD+KxlGd3fSwgLbJjwLY9EcFQY7L6BfDcwgKFxo8PdPkVztuhShZm6hhb1kw3qWsrkuV9Nut/8AOyyUtROObsEyRuuMwtsiF3+5u8rJ12Q9N9oCl+CycMP6EFZha3HDyNjXiXRi6axeeQ== 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=CvcJZ6DYdnwZYZXrSSXSTcQt1Ki1RAvt0TsNQwot/OA=; b=wgdnfOkECzHrbdsUJDvfDqPWKt+MLayfSmRthPqX4XR4cu62SEt6RlPFZ5YLNWw0NmGgNoysN7JSzXPf2Vl5f1Mq2x4Hv3jcXZQuVgonBUOLlScnZLGsbpTC/rXXHRQlVjJcPMIlWgO79GgzjSL2Vw8rlhrif21c3mdxiRbCTHI= Received: from MN2PR10MB4112.namprd10.prod.outlook.com (2603:10b6:208:11e::33) by SJ5PPF8DB18B996.namprd10.prod.outlook.com (2603:10b6:a0f:fc02::7b8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8511.20; Sat, 8 Mar 2025 18:16:04 +0000 Received: from MN2PR10MB4112.namprd10.prod.outlook.com ([fe80::3256:3c8c:73a9:5b9c]) by MN2PR10MB4112.namprd10.prod.outlook.com ([fe80::3256:3c8c:73a9:5b9c%7]) with mapi id 15.20.8489.025; Sat, 8 Mar 2025 18:16:03 +0000 Date: Sat, 8 Mar 2025 18:15:53 +0000 From: Lorenzo Stoakes To: lsf-pc@lists.linux-foundation.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Jan Kara Subject: Re: [LSF/MM/BPF TOPIC] The future of anon_vma Message-ID: References: <9c2f802e-d1f9-466d-b5d2-b61e5461da30@lucifer.local> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c2f802e-d1f9-466d-b5d2-b61e5461da30@lucifer.local> X-ClientProxiedBy: LO3P265CA0014.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:bb::19) To MN2PR10MB4112.namprd10.prod.outlook.com (2603:10b6:208:11e::33) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR10MB4112:EE_|SJ5PPF8DB18B996:EE_ X-MS-Office365-Filtering-Correlation-Id: b5a8d238-efa6-47ab-dc16-08dd5e6d491f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?QKTp3835DLuxtxRLv+Z8Zrjis4Us9CfPt30zH5Vdb8LDi5xNuxBfpvuqkfzU?= =?us-ascii?Q?CjHYIG2nQdfpROrmA3118GOCnAjO38TZHKnieBlDkiraJN8qAflbJlQi77tz?= =?us-ascii?Q?AsWrieshfrzwi6JIR1ViBaf6Qt2jrOPNCNKBz+om4aDI01GY8jPua0mGkWDo?= =?us-ascii?Q?QZbV/B4LHc9kDzb3kir0AbthIu9UIkTyMNmTbzH4RpgJrUs5YCyRr5kUMgDQ?= =?us-ascii?Q?z/LUXDB3aS4OXIorz69SyJogzafB6tnDCuCi14s1AVDrLhg3V3cNNkrcjs0p?= =?us-ascii?Q?Hn7DAiKuvU72GVoy+bhklcWe8imJfZGg4Jv+oLvYeczbvmpqFfKvnWxbOY3O?= =?us-ascii?Q?jm+GUTmEJ8Wbl/0KQywla2B+64+jO04e8ILrPSAKbUx07Ahe45eUc+aks+rQ?= =?us-ascii?Q?FeFBwuNSrKJY4Y1fgIs5c/7dfnPGjDpgLOEB2xu95rCiGGvUfQWQonOPlZ0u?= =?us-ascii?Q?uF4pY5iCetNx2GeCIzpDXkR2NdW6APRmjue0l+5UxcR0laPBayuHp1MsgN93?= =?us-ascii?Q?+uaRDG7kgW5gOlaCzlJ/zWcjYSIw+j13rOJs1/FoCUS4fV9X0Q1rMJH4tCis?= =?us-ascii?Q?gCpu+2n4Iihk4JsGqr9MmuQ+S53FV5X8npgjZpZpTkpNmYbnk95U2N0mZGJc?= =?us-ascii?Q?BEOUm18O5IrUHw1B+63yCwkSKuJ3rpN9+GsEn+u2KkGrEKZwNlkwwYmV18Na?= =?us-ascii?Q?wFedWiea1+rpcdXGjz+KFN78wfn8gm3GBD57HDGFPzQmqVem63CfwJMK5WIq?= =?us-ascii?Q?zEThggTRnjAbSwyiulOBKYdXMLzNJzEH5h5sG29+SyRzxn0fiV2B1tI909IJ?= =?us-ascii?Q?O9NyhV9y0D24Al/EQ2VvcJfwoXK82xXXba/heiZNHSTAVuSSJ5CYHpMzXgqc?= =?us-ascii?Q?o/dBr91IHM3QOOgtDHa7yImpmNIMXT3ZSYr9TZcFsUrs2wutiD7QU9bRRX76?= =?us-ascii?Q?B7ybBf4UZ8PZEuzuz+Hpq8cwlmq8BnH+MyKL3W8XVmy8vZWYJjE8qHoKeSne?= =?us-ascii?Q?G1m2ITEuhPWsXRqnpfW9ceo3Wehh7E7suU9etkcfLSwKMYaD1YqpDs0wDFeq?= =?us-ascii?Q?H1idjNZBbCMbXRQCwKqre690liMe42MvOdIaLu4QZruPJTXUmy47dkloN5LT?= =?us-ascii?Q?2sVwYKJGmoyAggGw98Ldb2nDr7Pe6chvNdLJvp1qgblVab3owmXFt4RuDQ2N?= =?us-ascii?Q?REJN8WGVZuH+voMYl87tpVi/ktg7QnNDCZLtxwepl95bmWo+GgWhKuo/pzlF?= =?us-ascii?Q?fzEq+OoG82+b5W9XnNSHY+37K7tcTivBIQz9kbI7O9/82nd4x1g5y7M3VOY2?= =?us-ascii?Q?8xNS7DnMMvACELnN0XMnp3Cp7PFbWXSwtaJWmhyaI9huE1wt+RbX4ssE1qvd?= =?us-ascii?Q?EzIyZ//uw1VjDdra81xOv5cnHSGV?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR10MB4112.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?TvN6GJULSqqzCi2j6BzGSClS6k7zlktj1cwXCFjddgXwy2B9UItkgQZXUtwF?= =?us-ascii?Q?8rjeBtoaxK6uGB5+wPxu35pRgSJPqGgPpWByFaKHAoSUV60kyWOu9doAKYAp?= =?us-ascii?Q?XhKrV+yHF8x9CI9VpAK6Gr7p5C6So64eytwFQYHGXjlKIT21mCsuftMT/qRP?= =?us-ascii?Q?L6svHn52QxlxlwcboVqXsgx2oPZ1fX5Bi4m8s0wZVQdF8RZzuUhLbC7TlqL0?= =?us-ascii?Q?sgXnkK3Z2Go0uekT1UzIj2yNEKzg6mzVuaxSl6OusWNmNDeocy6suE7hG2nR?= =?us-ascii?Q?KXuyZAyV5j3Nhvm7PydrLvwG3QfWLq26JpTZuOJ7yHnCISepsG6lxAZgFn5P?= =?us-ascii?Q?DcGENvLiihc+EvxHtoXT96fnS4ifRj7slyMy3xUckEkvAFI7hHYgrwbcQEbs?= =?us-ascii?Q?J1LG31217xnfxn4td3geVp/xBL4qFNSq7Q8Fbf+kKqcbRiZ9YIOOQaA6XVa8?= =?us-ascii?Q?/RoJaP9VmyS06Hb8cXbgGAdrwTL6u9VVyXuaS2sXFzqtg6P5sbiHN2s85FoI?= =?us-ascii?Q?bTJg38+mUCgHkgW1OM2ZPsPZ36gsLoVDj3AosWY3BrOTlFBLb7/GyEKHK7eH?= =?us-ascii?Q?yKm5dsLQP8YnA3QQmXHdngRpw1x0dhvJZ3NypeaZLYoOI6ZEB3LFXkCwKf78?= =?us-ascii?Q?0qtbxwmqBVv90EfU1rL3j0jGsxWidEhEQDjJeaQgN/w8EU5dyHDufpm9Ubw2?= =?us-ascii?Q?o9PEPnD4Jf3I/pXnjcf2MGtItHw53rJ87kc2MicuWNk/QbRg0TkhOFlefyVo?= =?us-ascii?Q?5PDBAPC7coGktu2cZyus3XKHFwjELV8rn2Q2b/b4FdV7Z8wLTuE2qHIOpnbJ?= =?us-ascii?Q?xCoxqJJy65TjIvSDqGcJ5duEokGv8uIFN5beM7ESZJf3EmSEeOiYuBIhKvs0?= =?us-ascii?Q?r1Zia2ie3qBUgO8MCFNmEtkGw8HSfURwCQdJKo/kv/X+SKHLdVWhJj1X772a?= =?us-ascii?Q?Mha4sNNHxEdKX1YknHdRyTGG9FUrFwf6rvd8xodXi1Evo0bqlMJZc8rok51N?= =?us-ascii?Q?FQwxipav20hLOOMFN+DYijy/gk5S88/NXirtTYpMIUiA9lzcJlwuU5yw/7ee?= =?us-ascii?Q?UhZ/IsRY15Ca924x8S0/8YHrbDXDgx7V2Y7mVOSc/Rcfo2Vu/ir4a/kODaDY?= =?us-ascii?Q?0oIEPQsjOy0V25kLp6wof7a/WP09XKiDcf/B7PX9B4T8BSRrmVfAVokjsu4o?= =?us-ascii?Q?Fpu4W0MHIzmOWnVNqKF2vQNWmUVNZaQKow/BcZuUgTZMjWR5jNKZwg7Op9jF?= =?us-ascii?Q?W5Zf3QX70Z1HbXdHdsQ0UKOfNwPun6sJQUULfP/VKJdz3/Bc0JpqHvIKqpjW?= =?us-ascii?Q?FIGXThHu72Z+M1Op9sB+WVPeI0n1mnaS6phzYMGssOYSMP4hegc7j5B01RVP?= =?us-ascii?Q?hZ/M3Z8gA+9qfjLke/jYKcc68+v0tCn/uYHbK4vqYoobHQxWid8dUxHNsXkC?= =?us-ascii?Q?Kw4f4WQF3pvcQeLkxYLFDUAlJ4pFebiHhvw+gRCKAIO5hWNwhxE61tJHfEhB?= =?us-ascii?Q?0ndNXPYAZWELu+09MkFSYrm1LKHhwi1aaEmR8vyRbrOC32PdTqzsVKed8FDE?= =?us-ascii?Q?fsaEIoXYJDGytIJwF5ZL/137qmCi5Cu+WseOuWp7CIuFgTLpAvwOjQO2arqv?= =?us-ascii?Q?YQ=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: b5a8d238-efa6-47ab-dc16-08dd5e6d491f X-MS-Exchange-CrossTenant-AuthSource: MN2PR10MB4112.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Mar 2025 18:16:03.2572 (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: WWL9pAvK6ccwL8AFRrX5EF88Z4ckOQKeB5bOHg1KZEJVPGYYt0OevfXWOPzV0HfA+5nloO/iMJJSawmDxiNCkCE0UNlPh0v6xtwhP9SLk3c= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ5PPF8DB18B996 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1093,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-03-08_07,2025-03-07_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=898 mlxscore=0 spamscore=0 adultscore=0 phishscore=0 malwarescore=0 suspectscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2502100000 definitions=main-2503080140 X-Proofpoint-ORIG-GUID: YbYqkzuCxpfwrD9tvU4VLOW3phsoCOO9 X-Proofpoint-GUID: YbYqkzuCxpfwrD9tvU4VLOW3phsoCOO9 X-Rspam-User: X-Rspamd-Queue-Id: 36BCD40007 X-Rspamd-Server: rspam03 X-Stat-Signature: rx1knqwz1ikfc3s3x9ifwxgs1amad4ir X-HE-Tag: 1741457770-573000 X-HE-Meta: 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 F0g4rMn5 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.221386, 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 Sat, Feb 22, 2025 at 06:26:32PM +0000, Lorenzo Stoakes wrote: > Having worked on slides and done further research in this area (I plan to > really attack anon_vma over the coming year it's a real area of interest of > mine), I have decided to modify the topic a little. > > Rather than focusing on the possible future ideal very-long-term project of > finding a means of unifying anon + file-backed handling, I'd like to take a > step back and discuss anon_vma in general and then examine: > > - short term improvements that I intend to attack shortly (hopefully some > of which I will have submitted patches for -prior to lsf- as some people > are apparently adament one should only speak about things one has > patched). > > - medium term improvements that require architectural changes to the > anon_vma mechanism. > > - and long term improvements which is, yes, unifying anon_vma and > file-backed mappings. > > I think this will be more practical and we'll get a better more actionable > discussion out of this approach. I'm going to further refine this to discussing anon_vma in the context of VMA merging solely, and leave the bigger stuff to later :) This is in relation to an RFC patch series I have been working on. > > On Wed, Jan 08, 2025 at 10:23:16PM +0000, Lorenzo Stoakes wrote: > > Hi all, > > > > Since time immemorial the kernel has maintained two separate realms within > > mm - that of file-backed mappings and that of anonymous mappings. > > > > Each of these require a reverse mapping from folio to VMA, utilising > > interval trees from an intermediate object referenced by folio->mapping > > back to the VMAs which map it. > > > > In the case of a file-backed mapping, this 'intermediate object' is the > > shared page cache entry, of type struct address_space. It is non-CoW which > > keep things simple(-ish) and the concept is straight-forward - both the > > folio and the VMAs which map the page cache object reference it. > > > > In the case of anonymous memory, things are not quite as simple, as a > > result of CoW. This is further complicated by forking and the very many > > different combinations of CoW'd and non-CoW'd folios that can exist within > > a mapping. > > > > This kind of mapping utilises struct anon_vma objects which as a result of > > this complexity are pretty well entirely concerned with maintaining the > > notion of an anon_vma object rather than describing the underlying memory > > in any way. > > > > Of course we can enter further realms of insan^W^W^W^W^Wcomplexity by > > maintaining a MAP_PRIVATE file-backed mapping where we can experience both > > at once! > > > > The fact that we can have both CoW'd and non-CoW'd folios referencing a VMA > > means that we require -yet another- type, a struct anon_vma_chain, > > maintained on a linked list, to abstract the link between anon_vma objects > > and VMAs, and to provide a means by which one can manage and traverse > > anon_vma objects from the VMA as well as looking them up from the reverse > > mapping. > > > > Maintaining all of this correctly is very fragile, error-prone and > > confusing, not to mention the concerns around maintaining correct locking > > semantics, correctly propagating anonymous VMA state on fork, and trying to > > reuse state to avoid allocating unnecessary memory to maintain all of this > > infrastructure. > > > > An additional consequence of maintaining these two realms is that that > > which straddles them - shmem - becomes something of an enigma - > > file-backed, but existing on the anonymous LRU list and requiring a lot of > > very specific handling. > > > > It is obvious that there is some isomorphism between the representation of > > file systems and anonymous memory, less the CoW handling. However there is > > a concept which exists within file systems which can somewhat bridge the gap > > - reflinks. > > > > A future where we unify anonymous and file-backed memory mappings would be > > one in which a reflinks were implemented at a general level rather than, as > > they are now, implemented individually within file systems. > > > > I'd like to discuss how feasible doing so might be, whether this is a sane > > line of thought at all, and how a roadmap for working towards the > > elimination of anon_vma as it stands might look. > > > > As with my other proposal, I will gather more concrete information before > > LSF to ensure the discussion is specific, and of course I would be > > interested to discuss the topic in this thread also! > > > > Thanks!