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 C49C2D15DBD for ; Mon, 21 Oct 2024 16:51:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4D7176B008C; Mon, 21 Oct 2024 12:51:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4880F6B0092; Mon, 21 Oct 2024 12:51:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2D9F76B0093; Mon, 21 Oct 2024 12:51:46 -0400 (EDT) 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 0C29A6B008C for ; Mon, 21 Oct 2024 12:51:46 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 8B383A1AB1 for ; Mon, 21 Oct 2024 16:51:17 +0000 (UTC) X-FDA: 82698200676.16.0A1AD47 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf04.hostedemail.com (Postfix) with ESMTP id 2EDDE4000D for ; Mon, 21 Oct 2024 16:51:23 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=EvESyHcs; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=EV1E2May; 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=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1729529303; 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=q7U1R8bVVbgVd94/6AAAIei+GiyQcReNb0+odjxLTMc=; b=r0MiKIv78QChXPTo0YSR9LFuOLo6QgrqkEDM+8qPasuGq0cB4bFwq19T4lPIyT2S3kS7A8 K9arsNmQ0qgxydkEQObi+4DkVMRKMSW6zdUkqMZyoQ1pB/UYn8EYyTq28GQsctypXYekER LuSBza2I2pdPtBOiUOat78XLqrbjKjI= ARC-Authentication-Results: i=2; imf04.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=EvESyHcs; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=EV1E2May; 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=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1729529303; a=rsa-sha256; cv=pass; b=03PqMfd5WnInbuD+5sWjVihVBpbyzBv+enAgtWgXeUZJTBj4DgOr19zGObAczBMjp7xW8Z 0+1j1GLyzBD9revY+JLJyuFr6xc7GcUIBXr7th6QgFALHQ4dtn+JGbG48LhGsYCzR5NBni 55ChPS6KXDJ40UZIJLuSH6t7B7NqGQs= 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 49LFteU3017300; Mon, 21 Oct 2024 16:51:15 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=q7U1R8bVVbgVd94/6A AAIei+GiyQcReNb0+odjxLTMc=; b=EvESyHcsAj57pIrVzE/y9j1L9xTfyWL7sQ BAO1lT/UN+8Fm9EbBHQtg9nHykNpzRozsCZU2xf+mBudoBASrUkjW8dvPWjol4mg IUqJKiX/JDMzjeV93JJCXiktJCSx6p26XLfTZRHF1l0IQnZY7i7QqOcP17X/NdMs ELnIhWIV6AMIiiZqgxYa37p5xFTeIz1kSrJTuP4puK22yMttHxsu31udufPGZc1T /XMUHBy9GfW7V693fkQYtKGjblvxk0LNMtCJjn5sSTZHSqe0IuyEw1Gl/l5dqJ8c 020Kui7/6E/eSyVAlItGGo97UTVrZ9eXWkumrEhF/XB/JqpAz6KA== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 42c55uumv7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 21 Oct 2024 16:51:14 +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 49LGWnPB020473; Mon, 21 Oct 2024 16:51:12 GMT Received: from nam11-co1-obe.outbound.protection.outlook.com (mail-co1nam11lp2175.outbound.protection.outlook.com [104.47.56.175]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 42c37cqsrg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 21 Oct 2024 16:51:12 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ZWESSn/jJYatLhnl/EZMNtQf9pu92I/9dnxPU2KM1fPy2gY41w5roZDzRMU0Rp3UcU9NiblCoF9uyZs/3Ot0BZoS4Dqr4zfGkVEBI4AXzp1PYdioJqv4ODXpo2+KghxBBJ/LEq8+DXnIQY98BbmYBjqAYFgGgPvt+PHC5k81WAW5pEIPnVaVvhj8d7R+kOrKwGV2LpaSuPa28/YMmFh1hV3ixusXnQQYvcqawgSb0+2hM13eEG1ERouQj0LaYSf3/Pr8lunCEWST9XtODpgqtDpQmHs/ClnXb864p1XkjIfWd9Eb8s2MA1OJaIhSNPsY2454hVy/RRVqu5cm5UMMFg== 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=q7U1R8bVVbgVd94/6AAAIei+GiyQcReNb0+odjxLTMc=; b=BIfTozrV6g8dHwpVWWTfVt5x59CxihJxmb6zUuSngUCa7mpjqFjsanlw5+UOlcoqmXBWZelHlQDX1ow2t6mJlXgwbHCLz/fElUk6j10xKHErqOT+m1ttPW1oldN7DuXTXCsf2DWDLQjkEokXCPkXAgwO5Lhr5Guca7lt2u/Hr4CgGiUp/cFh8KUrWKYcEJd0zoLrCdQqYSUaQrODukJreqcmAIsq47r5qOmNHLz2CI4Fbbg8AeU9e5+WPrTx58cI7SjVjIQkQo+Gagc0HRXLzn1mzFWpa5aOzfzXx3UpvHX6PI1XtO50B+0nTCNfp85rbbNg3q2DEb5m4Nt799v4Sg== 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=q7U1R8bVVbgVd94/6AAAIei+GiyQcReNb0+odjxLTMc=; b=EV1E2MayFON1hUJBCwOiP3OxuKDl+N4tXxp79nGDCq46d7tHyJ/KNEVHDS4DuLbl4Y+tgpx4Q8IQJQCXfUAU+NfM0DaJ3thKkhAVFraw4yRz+v7kHzJNIIhCCTTJHLfFK5KBra7W8ZFFfscBt7a3XYg6TPtmC65IRjIaM2yFfgA= Received: from BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) by CH0PR10MB5001.namprd10.prod.outlook.com (2603:10b6:610:c2::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8069.28; Mon, 21 Oct 2024 16:51:09 +0000 Received: from BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9]) by BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9%6]) with mapi id 15.20.8069.024; Mon, 21 Oct 2024 16:51:09 +0000 Date: Mon, 21 Oct 2024 17:51:06 +0100 From: Lorenzo Stoakes To: David Hildenbrand Cc: Vlastimil Babka , Andrew Morton , Suren Baghdasaryan , "Liam R . Howlett" , Matthew Wilcox , "Paul E . McKenney" , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song , Richard Henderson , Ivan Kokshaysky , Matt Turner , Thomas Bogendoerfer , "James E . J . Bottomley" , Helge Deller , Chris Zankel , Max Filippov , Arnd Bergmann , linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-arch@vger.kernel.org, Shuah Khan , Christian Brauner , linux-kselftest@vger.kernel.org, Sidhartha Kumar , Jeff Xu , Christoph Hellwig , linux-api@vger.kernel.org, John Hubbard Subject: Re: [PATCH v2 2/5] mm: add PTE_MARKER_GUARD PTE marker Message-ID: References: <081837b697a98c7fa5832542b20f603d49e0b557.1729440856.git.lorenzo.stoakes@oracle.com> <470886d2-9f6f-4486-a935-daea4c5bea09@suse.cz> <434a440a-d6a4-4144-b4fb-8e0d8535f03f@lucifer.local> <4f4e41f1-531c-4686-b44d-dacdf034c241@lucifer.local> <49afa956-21e1-4b3d-9dde-82a6891f2902@redhat.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49afa956-21e1-4b3d-9dde-82a6891f2902@redhat.com> X-ClientProxiedBy: LO4P123CA0443.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1a9::16) To BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BYAPR10MB3366:EE_|CH0PR10MB5001:EE_ X-MS-Office365-Filtering-Correlation-Id: f0ad7493-5243-4381-6862-08dcf1f08fe3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?l5T/y2gm0CIAm+m0lNkODVGdzhmoSr/rvrYUv0JoyfeZJ9a7vsTG8A9kpWDT?= =?us-ascii?Q?Ll1BKRBRpfSaKEhOtDz7W2Y6a+3kyEZ/mXXiqwW+/Yn2+q+VEKav62SoWnau?= =?us-ascii?Q?ijcskuWX72jG116rCAP74/DZrBG8Rftkb6ns4T5Dz94/1n8c6+biTE9g8pkN?= =?us-ascii?Q?VEYJZX7V+lhReIWsCtr9Bkz1bpfeDlmOEk/adauWrfc6a5WvJtWNDkEnZhbv?= =?us-ascii?Q?K3KwqwexR1Cc++B9jtGYKmPwxkU9gk0ClHMVbZ6x8bd/w61++vwmqto8qSae?= =?us-ascii?Q?M9YdixlFXM/syLVBlBqt2ZLHdyZkdbfXOVyZQo/8kxWIzEjSexb8HEdPXsrB?= =?us-ascii?Q?w8CXSOeR2FJtqYczynr5p0udwXUWKnMLOuoLCR+OmWRXjsh1jfL0usUlgMWk?= =?us-ascii?Q?pbVOV7zLXmV0PsgeK8olp/bpfIRTvXDClS6VvA1Z0co4rH9Qt0DN3J0KZWCv?= =?us-ascii?Q?AYYe/MlS/zyFrFOQ1Td3YRRLeA9djj/8Q+HW+qXd95WUmUXHF23z+CVB8XOi?= =?us-ascii?Q?mikBj34Mm2R/q4h1t0cCRU2AYX09XCMYJIQFVY6E84vorIB1WfGmAdfIwBad?= =?us-ascii?Q?p8qukgz3jGafZKuoOiHoonyvrT2Xd14iKUS6UK8c1VaDm4HJhGhK7fCNyaGt?= =?us-ascii?Q?enuJ4yYSnEUIFMK89WV2t9ML+vGGycA5FGHaWeHHL0UH6JcPbSKYcGsUcRql?= =?us-ascii?Q?qJ5KtBadeM2W6UyJazPgkB3HE0gZ4ROunhG6VhU77Hu9LTkf+pIMGk7YOVc7?= =?us-ascii?Q?nEnC8gKP+Y0mIwmiUr9NygCBovWlOd1CXj11WyHiC0jAiNdQyV4q/06rxqEh?= =?us-ascii?Q?42W6FSXMjXyapMS15TQ+Xudivbjn5cqMcZTL+1pomCRipKp8tYK2n+iLglia?= =?us-ascii?Q?uCfdZndlxpLiF1rUjUSfd5td3wOtl9zgYOtPxjGoRa6Ox6OkIW+DTEUMqDVB?= =?us-ascii?Q?jHu6ELTrZSdH+I4WcFcXzAYNCIlsBXCgjKcDZViIr6z8WnHN/S8oIhkd70E8?= =?us-ascii?Q?vq3OmRr4yuMW91FX8KaF+yvnfs1htD2QimYk7w6f4aC3OZ96k71Qnlwrj68C?= =?us-ascii?Q?ae6uNXiZ1rlyJ072y35X0tteKntXhs+g0Cm8Bxf/5YwAnkusyc84Fsv+3ZtW?= =?us-ascii?Q?sf7wyHxeQ4d41gRi9vcK8e3UetSsUMBAUJaLNs3WkDMqMDc1qG/PxQT0H2Eb?= =?us-ascii?Q?QMvX+dE2/cnANpdsSFD/l78GvyQfbHmijvRwUGg+unsi1JCCnMJt7a8L5DRa?= =?us-ascii?Q?Hl4DkPz3tld9uCLhHB4WM+hMqpBXI7mqN4KQGPuZGvrOfy/gzXkPUDHxxWfg?= =?us-ascii?Q?xLH79zsCgT3weUIV1ABoaCNm?= 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)(1800799024)(366016)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?fbs9nF2LKpviYlDbQ5YDQqhUrvmsnJlpT7hvhSeixsTdma8/MrIoTiYUa/Pm?= =?us-ascii?Q?L/Oli2QNQ2prScLhz6JvcvGtYSePGrT9Ngx71B84lO7mGP/4043oe4mKFa65?= =?us-ascii?Q?nqIHI0HmfEyDe5Rr9SWuN7KuJVFRftlxdvmxRwucX7h1ngnG0vp7aL91hmF3?= =?us-ascii?Q?8XzWAKU+KzC7+cZU7IbqFf6GoJZXcKcXKCatJsiW1F8Fy19vZ4rEHrrY20fS?= =?us-ascii?Q?xZ5ov8nCqB6D8X+WynkXJeQT5jB4lcZ7lN0boIDD32Pbya16XhZU/QeNx3t0?= =?us-ascii?Q?9TM0qoOL3t4S8VcFVs+7UuBiFezN6mxFlBJGFVMPGkGWTXiC7w2cHt1eIlcd?= =?us-ascii?Q?fFcItn+wOkxa+OZJBBO2xG/883H9+24nZGPeStO76F04r4Jcy0oCGAHB0PfY?= =?us-ascii?Q?Vpbpt+yERaWX5a5INo9+3L538t7YqvekTURRjEQqlTeSBHNpNnAe/VOTUQ7U?= =?us-ascii?Q?ieYgc5kR43E3h+C5hr5so2jpYanU/SPNeST54WTkPQnG0Guae5BmpVyWTdIV?= =?us-ascii?Q?ft56C4nalNBDetS5feCpwT5WVlq7qosHGXxleSA1S+ysZ5iQ1u7QOAj+Dlg1?= =?us-ascii?Q?PXUmc/lb7Jt6HdJOEjegcmdRHIpvinsKuE16oFXYu2uC9oQW3QpiefhuVtL8?= =?us-ascii?Q?NQvdDWwNsJePrOfoc7YLvpbxRH7tqzyJcLMXzja4+L+C8JGG+omdHm0U7oaw?= =?us-ascii?Q?g/4CCEUE+32te+2uz2L7AA4crNtfTEC2Ggy7TkxZPFoYdAubscup6GZkzMve?= =?us-ascii?Q?nfja4JWvZitRvEXGmvhtY5JF+Tq1AWDIxDHpqsan3EE70qyuTRs39B+ryTc/?= =?us-ascii?Q?x4YGzqrzdI9oO/AZ5FVgjHZqPxLIHhXYSv/jdfEZ8qwZHUaiNK+igayR3h0C?= =?us-ascii?Q?TJ03Pl5H5d/IqKHA+uh3gExlVPVhByW/RORWyVJS3ZZoqAynqlKJlO8+SUWo?= =?us-ascii?Q?TVN2CO1Fcx1l8T23r+1ZJmIhA0FniW+u/91+Mu5Y/hkJ9VxyzDa2fgl+n6iQ?= =?us-ascii?Q?QU0QWgYRFfoZHT9TjVc5jOTR2Shjap4IVkftDTy7MRNjuHKWn8qF9pT8kKbx?= =?us-ascii?Q?PLwfEZR4H4Rxi//046yeygj2KBxpG49bV926pAsSy3kUf7hFED84HTc+67KI?= =?us-ascii?Q?Gwa5O0U2VHrGs1T7n+VP373YRxiKaIhNIVwqoeTv85Pf4wQe7MkGCcB2Oq6x?= =?us-ascii?Q?NuBMKakdxZ1pvHmfriijJws9S33NKu7gwupDs32h3N8xgn6eZLoBwzbSPoCh?= =?us-ascii?Q?+S3Mno+4QddTBjuMJdk1fdbZmFQay4ohGjDzUcMrge9Ki+cFpUABcS1gBNFf?= =?us-ascii?Q?KMBQlr/EPttM51/EqYGeLzeqJq1uvThQwK6qgU5BOey8XZX9Vyv7iU14nmln?= =?us-ascii?Q?nBhYBy5ZF1vZorpmVPgGdvJIn2Ia9QLviNgg4lxI1yjYLJQNtq52CfGMz/Yz?= =?us-ascii?Q?g/VSrvj/niAswcWEsWhdvnLv6j1f+c7Px2amnqSDcfovyVi2LKfjQZKMG+S4?= =?us-ascii?Q?DNg081b1PkZvMTrbr5KacWYLA+upoieBD7AEip2KeR1bnKz0/5sKYbYvxtse?= =?us-ascii?Q?nPirKr0HUVDrbrLwdEOzfWDFuAIqT3x+VJoJ1A5iwgJTK2d+3Acrrd+UKlkg?= =?us-ascii?Q?/A=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: f0ad7493-5243-4381-6862-08dcf1f08fe3 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB3366.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Oct 2024 16:51:09.0974 (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: QyjExegk2fvcm+vWGcz7aU5rMBnIfcEOOepED7kqxIG/ixyEAtZHc6A1DdawCL4aWKbupoQX9KCNaCAT5bY5XUSobiXkauzEicoDA+B66SM= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH0PR10MB5001 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-21_14,2024-10-21_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 suspectscore=0 mlxlogscore=999 spamscore=0 malwarescore=0 mlxscore=0 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2409260000 definitions=main-2410210120 X-Proofpoint-GUID: 1EAhxfwwfhZiVI6AssHnENFBlWc6DC7T X-Proofpoint-ORIG-GUID: 1EAhxfwwfhZiVI6AssHnENFBlWc6DC7T X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 2EDDE4000D X-Stat-Signature: 7ku3fzkqbmoqh4ef97aaywu7c1kjzeis X-Rspam-User: X-HE-Tag: 1729529483-730356 X-HE-Meta: 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 gohKG8mF 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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 Mon, Oct 21, 2024 at 06:44:04PM +0200, David Hildenbrand wrote: > On 21.10.24 18:23, Lorenzo Stoakes wrote: > > On Mon, Oct 21, 2024 at 06:00:20PM +0200, David Hildenbrand wrote: > > [snip] > > > > > > > > To summarise for on-list: > > > > > > > > * MADV_FREE, while ostensibly being a 'lazy free' mechanism, has the > > > > ability to be 'cancelled' if you write to the memory. Also, after the > > > > freeing is complete, you can write to the memory to reuse it, the mapping > > > > is still there. > > > > > > > > * For hardware poison markers it makes sense to drop them as you're > > > > effectively saying 'I am done with this range that is now unbacked and > > > > expect to get an empty page should I use it now'. UFFD WP I am not sure > > > > about but presumably also fine. > > > > > > > > * However, guard pages are different - if you 'cancel' and you are left > > > > with a block of memory allocated to you by a pthread or userland > > > > allocator implementation, you don't want to then no longer be protected > > > > from overrunning into other thread memory. > > > > > > Agreed. What happens on MADV_DONTNEED/MADV_FREE on guard pages? Ignored or > > > error? It sounds like a usage "error" to me (in contrast to munmap()). > > > > It's ignored, no errror. On MADV_DONTNEED we already left the guard pages in > > place, from v3 we will do the same for MADV_FREE. > > > > I'm not sure I'd say it's an error per se, as somebody might have a use case > > where they want to zap over a range but keep guard pages, perhaps an allocator > > or something? > > Hm, not sure I see use for that. > > Staring at madvise_walk_vmas(), we return ENOMEM on VMA holes, but would > process PROT_NONE. So current behavior is at least consistent with PROT_NONE > handling (where something could be mapped, though). Err, the handling of holes is terrible, yes we return ENOMEM, but we _carry out the whole procedure_ then return an error, an error _indistinguishable from an error arising from any of the individual parts_. Which is just, awful. > > No strong opinion. Well you used up your strong opinion on the naming ;) > > > > > Also the existing logic is that existing markers (HW poison, uffd-simulated HW > > poison, uffd wp marker) are retained and no error raised on MADV_DONTNEED, and > > no error on MADV_FREE either, so it'd be consistent with existing behaviour. > > > HW poison / uffd-simulated HW poison are expected to be zapped: it's just > like a mapped page with HWPOISON. So that is correct. Well, poison is _not_ zapped on MADV_DONTNEED but _is_ on MADV_FREE :) anyway, I mean the MADV flags are a confusing mess generally, as per Vlasta's comments which to begin with I strongly disagreed with then, discussing further, realsed that no this is just a bit insane and had driven _me_ insane. > > UFFD-WP behavior is ... weird. Would not expect MADV_DONTNEED to zap uffd-wp > entries. > > > > > Also semantically you are achieving what the calls expect you are freeing the > > ranges since the guard page regions are unbacked so are already freed... so yeah > > I don't think an error really makes sense here. > > I you compare it to a VMA hole, it make sense to fail. If we treat it like > PROT_NONE, it make sense to skip them. > > > > > We might also be limiting use cases by assuming they might _only_ be used for > > allocators and such. > > I don't buy that as an argument, sorry :) > > "Let's map the kernel writable into all user space because otherwise we > might be limiting use cases" That's a great idea! Patch series incoming, 1st April 2025... :>) > > > :P > > -- > Cheers, > > David / dhildenb > Overall I think just always leaving in place except on remedy err sorry sorry unpoison and munmap and not returning an error if encountered elsewhere (other than, of course, GUP) is the right way forward and most in line with user expectation and practical usage.