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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ABE0EC54E71 for ; Fri, 22 Mar 2024 12:29:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=kSMAvJHbHLAVob6XGZTOaIROUl92YCLsI6iPdSMt7R4=; b=iiYhVWKzzC32JF 0ELKQdmU2JE+qkNHfjzHqV7jeNpFGobMsem6QQpGdBuuOoc7nYGYTDrXzshZnF6jkhW3yz8mYRvzM TigyiUVfKe930vieya12bwjhZBAJpY0F9ZsQRX9iTG1Hk5MsETbLFk48z/VVN0K2eENMuV0yzsUMK 8S7CQ0LO6poBh2IFIjniehG7UVcN1wMQ+mP4WCbhLkhehTVLBwBn3bqMEAQfHeIlq+wpqYpP99idE pDiokE6Qb6PsEgnxrTPv+QAMvGHx7LcqEl8XenyFsNjeHloikBT+nnbR2FFnxzOpE6ZEamI/zBcP/ E1IBfxwxWAE3ABna8ivQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rne12-000000077aY-3LWV; Fri, 22 Mar 2024 12:28:56 +0000 Received: from mail-bn7nam10on20600.outbound.protection.outlook.com ([2a01:111:f403:2009::600] helo=NAM10-BN7-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rne0u-000000077XP-30CR; Fri, 22 Mar 2024 12:28:52 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=M/L5rXMlH8oiI2J6oqzgrh72r27VDeYnWVJ/EY1/V9YcdN9SpmMz450ZPeyrEAb0ut9f/VXiemYwMVj0SN2a8hFTEMYanSjLMoEP3Z3PQAD0VNLr0VZU1V+dxmGBNrkYAVecGro23nQauH7UpkTPylJ68D4A/Za8/3v3l3FTCnahyQJa20XYw7AlphylyTTUMJNdD+gp3oANDYd53X34SjB7WEWG7yvqixoa7Pb4bpplHro8lMNNYbRfIwgDVpqL5PBIvnVLB6r3wEl6OXmF/a628zUVHB/oQ+JcWXwGeHu/KA5IlY8Yu5DcsRZQNTNM9cNPhJ8EeP+wkvMSGSjrlg== 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=dDkdacFtxB4qpcWdtAhoFkR9iyBLJ80XO7PfYd0ZaZo=; b=OiafJN0oRHFiQp6rBeCaXROCqnmJoqkNuW5dnP1P/1x/2DDC0Yybg3W/vWdW5/MZ0hj0q/cKWwbVEcZyb/g8PIXelLA/fcpg24LX/4tccbea7UnUwECUmwPU0KL1zOUPNCNe3CZabJNy8YTLzdqVdJfO2e4KsVOlPsBaRIKhQYV3E5dhzORMHxeFYXAoMpRMUguysdjmNrHpAGr9ZXC5hMhc5hCWWJxLkUmrZC07qLT/B/pTmcVV7eKDc4DnPVSbwhhO8O07YCYOVGNYgjaHxtjCI5p4TOnDcoPCRU9L/n6U22tTON1MykY+sSdOLSDsqi30RGSZgv4Pk2CHxQV0cA== 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=dDkdacFtxB4qpcWdtAhoFkR9iyBLJ80XO7PfYd0ZaZo=; b=MyQ4R56ZGrKp8VXSxsI9oyoz1f1pahvPhfNqJfFu6wV3wf5nbgynWTw58ce1ZMhv4Fjhtzfz4d5/9ijxUJ9+EyQgm+zFcnITBRoYsb+jWezbCE7IK6DCAzQ7s+lc5ennNdJPuc+LxQxeLB25seoSwoOdx/1tnatvTRHky+NMHvQ7WxfRGFEvDgMQ+KBzbdBONVhb008ghv8efwrTrqiHHEIy1RxnOWsx3KXraL1uVjDu26uofeLpIdcsztQIdGf8kxTuk/EY3SWxQ8Q3W61ij/8w41uQAaTvmGG575LBv4CBiphHS36mJ8O1kqf7U6lLlPUm8rDYOY+HA7MK6L6Tlg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM6PR12MB3849.namprd12.prod.outlook.com (2603:10b6:5:1c7::26) by SA0PR12MB4400.namprd12.prod.outlook.com (2603:10b6:806:95::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7409.24; Fri, 22 Mar 2024 12:28:43 +0000 Received: from DM6PR12MB3849.namprd12.prod.outlook.com ([fe80::6aec:dbca:a593:a222]) by DM6PR12MB3849.namprd12.prod.outlook.com ([fe80::6aec:dbca:a593:a222%5]) with mapi id 15.20.7386.030; Fri, 22 Mar 2024 12:28:43 +0000 Date: Fri, 22 Mar 2024 09:28:42 -0300 From: Jason Gunthorpe To: peterx@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Michael Ellerman , Christophe Leroy , Matthew Wilcox , Rik van Riel , Lorenzo Stoakes , Axel Rasmussen , Yang Shi , John Hubbard , linux-arm-kernel@lists.infradead.org, "Kirill A . Shutemov" , Andrew Jones , Vlastimil Babka , Mike Rapoport , Andrew Morton , Muchun Song , Christoph Hellwig , linux-riscv@lists.infradead.org, James Houghton , David Hildenbrand , Andrea Arcangeli , "Aneesh Kumar K . V" , Mike Kravetz Subject: Re: [PATCH v3 05/12] mm/gup: Drop folio_fast_pin_allowed() in hugepd processing Message-ID: <20240322122842.GH159172@nvidia.com> References: <20240321220802.679544-1-peterx@redhat.com> <20240321220802.679544-6-peterx@redhat.com> Content-Disposition: inline In-Reply-To: <20240321220802.679544-6-peterx@redhat.com> X-ClientProxiedBy: MN2PR08CA0022.namprd08.prod.outlook.com (2603:10b6:208:239::27) To DM6PR12MB3849.namprd12.prod.outlook.com (2603:10b6:5:1c7::26) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6PR12MB3849:EE_|SA0PR12MB4400:EE_ X-MS-Office365-Filtering-Correlation-Id: ab966d8d-c364-4bf1-e90a-08dc4a6b9d10 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:DM6PR12MB3849.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(376005)(1800799015)(7416005)(366007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?m26tBCNfyVStOXLVwAyNQSMBiqtU+WhZ98GDmtc0BbHhxLJbzdvQmQCpyOTd?= =?us-ascii?Q?JNe6WLDRpc1pL/Pwkh5R0KysulfEhdisK0BVtmm7d6hcN60HE+Q4wVLlQXec?= =?us-ascii?Q?R8ihPky77zKrrrCKBDxV6AjeyVvNOYW8i0rpG+95L69ius4oHf7pu3JbM8Lk?= =?us-ascii?Q?x9v9YWGwicJmWtPJvVBzz+PLM2oYdjyanl2A5wlyJXwy6KSxzGKUhSS3Dkp+?= =?us-ascii?Q?LxvuQdF0ER6RO2PB/BZEm5c74fmB52kHPHo/AYZTytD5vAJS5+wk2jBq6UK6?= =?us-ascii?Q?Qzwpb3w8Erclnc9o9oY+X50y6IUrUmfqc5ZLyAboC6G9I5xglLsKu+XnVSVz?= =?us-ascii?Q?6KCnGQ1KNrvfoKseLdYuKvVuUiDPDmLOQU6xtik+GE7G0owTNGa0a/wKI6Hx?= =?us-ascii?Q?xS0jaAyYNcKVVuN14zL4XZG7V88e75VrMRDa1mrLfNT6wsKyGg1aIf4jym6E?= =?us-ascii?Q?17/u5+ZbhyzQ4md2vxenI46oT9YOSuPU8NpHXoBOztmKSxBUitnIKj9PGijg?= =?us-ascii?Q?zPW/dTpnOE3PuAGRlqfW41i9uatPt/1dUzqd9fEZPzSwQBbFuDzIFul6T3aY?= =?us-ascii?Q?5umGtQxAKGaprc3coxcmGAhtlW3j2euaOeoweEMuD7F5nxdnidaPjTV95DF9?= =?us-ascii?Q?lIdAislSFbNuDTkDaxdRzmIlufXqbVKYc9N6At5hWRGr1xgNAb7uHlZpX3g/?= =?us-ascii?Q?nEZ3CuM6V5qCYULpAKEtwma+mjls70pCyupe6ZjtNimVmom0RqYoL1MgnLOJ?= =?us-ascii?Q?AN1gX1roHrV3iURNx2/aATLwDVeDr2RjdqX0J0Aoo9ESpLA2AwlchyvOLx44?= =?us-ascii?Q?QbzEEC25zNpg0eQhJaJR7yhXMExDte38tutRljeW/wl6xcEXodMugndSTVxr?= =?us-ascii?Q?KhWQW4RXFtsWzGYm48T6D56s09qQOpmpR51b5QTUhpjtKzqq636M7wLg5Wcj?= =?us-ascii?Q?d37VFtfF4bS+wT8CctezJeHTjiTwY5ZVTfv7k+d7wBNsFVF212UBlcFp3eFF?= =?us-ascii?Q?2e3YigLD+ulmr5VDkuP7qKZm4oRWxvkpoNTLe/PirWM6uAkwJAoV+sTsTSqH?= =?us-ascii?Q?d1gIbNp6yvy7HN8+7Jp4WkprLDd7/8HcoOvzhc+Ngs1hiGfvR0gk7YZDEwYY?= =?us-ascii?Q?qcKpebaJ8PhvpzQSHRvAxZ6Ns92N5RsxoW9khetiIsbJIHHQQNZ/DQmbvsLQ?= =?us-ascii?Q?YP2xaeT921/n38Ry9aSYPj/S8wg4XKhH0hQAOkKg3BlYhTSBB03VDjf2miCt?= =?us-ascii?Q?hkRAG6yPTLfWbuwdBo3TjxOiBsucpXmGBT4GSd1nbpAbPnB020Kk1iloEKSf?= =?us-ascii?Q?8jGguAY6sd3h6ITwd8zUcg4PLvbEr8J/wCkzluOzAcuLLE6LI0vhtKsSHCU9?= =?us-ascii?Q?uImdGfYLftkbRThrLjaPh9D7KtApMsABlihQshBPDuO86hafW04qNVgD67q7?= =?us-ascii?Q?KrwxJn0thmP58jdxA7ovZBP4BdImNVc/oUOW1MiWuJZnK2N0xBUYVeEMZ+Bg?= =?us-ascii?Q?uD8DbY6PdZGf254mSknNBlqfc6LrYZNOGGUmRx7omZ1XswCVmvwqXMrPlZ1M?= =?us-ascii?Q?PzxOTasoBORY14Ze5xuAw8+RA43k6s1teabQ47EJ?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ab966d8d-c364-4bf1-e90a-08dc4a6b9d10 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB3849.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2024 12:28:43.8149 (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: kKi1xHvflu29M8CoyCbXQXk/zZYiQ+Ipa+Ydojw+kkLvhrMansU7jp1FjmJ8K8Kj X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4400 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240322_052851_357158_BA200F7F X-CRM114-Status: GOOD ( 16.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 21, 2024 at 06:07:55PM -0400, peterx@redhat.com wrote: > From: Peter Xu > > Hugepd format for GUP is only used in PowerPC with hugetlbfs. There are > some kernel usage of hugepd (can refer to hugepd_populate_kernel() for > PPC_8XX), however those pages are not candidates for GUP. > > Commit a6e79df92e4a ("mm/gup: disallow FOLL_LONGTERM GUP-fast writing to > file-backed mappings") added a check to fail gup-fast if there's potential > risk of violating GUP over writeback file systems. That should never apply > to hugepd. Considering that hugepd is an old format (and even > software-only), there's no plan to extend hugepd into other file typed > memories that is prone to the same issue. > > Drop that check, not only because it'll never be true for hugepd per any > known plan, but also it paves way for reusing the function outside > fast-gup. > > To make sure we'll still remember this issue just in case hugepd will be > extended to support non-hugetlbfs memories, add a rich comment above > gup_huge_pd(), explaining the issue with proper references. > > Cc: Christoph Hellwig > Cc: Lorenzo Stoakes > Cc: Michael Ellerman > Cc: linuxppc-dev@lists.ozlabs.org > Signed-off-by: Peter Xu > --- > mm/gup.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) Reviewed-by: Jason Gunthorpe Jason _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel