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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95B69C433F5 for ; Thu, 14 Apr 2022 06:22:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229608AbiDNGZL (ORCPT ); Thu, 14 Apr 2022 02:25:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240145AbiDNGY6 (ORCPT ); Thu, 14 Apr 2022 02:24:58 -0400 Received: from NAM11-CO1-obe.outbound.protection.outlook.com (mail-co1nam11on2049.outbound.protection.outlook.com [40.107.220.49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A29C4E391 for ; Wed, 13 Apr 2022 23:22:26 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=M8Pftm9fQWOQBqKXTuePPTGp0HmxovbRnhOmgQ/IP45SN9tflDWDyTV3ZhNhJT7yKIIHG7h+/UoM/n2JsTtMNYUadB4INqSnnzG3jKIfJCoHeba9lUcNoWQwcqbb9QdxkhVUMabL+ZyX/W3zBzYxjyLVfUdrmBF6Yac0LXRbBD4yU/8+RFo4qT57NgWE6V4dlNTRphCTtIWcRjpPAnv2pMqnclvBhMHWxtvIgyhBdIkmYQBSii4KUoxA+TH8dW6WQo8iealKOa35yNVch7xBeGp28t9mmr0A5C1vqzE3E/1Ewh6Ry8XubEq44+ZQCeuN6kgF56su2UnXeYTqrL63Gw== 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=1eFOByyCoyroKu4xZeYyPYJ+1rLsJJTnNUjkE2PvVpI=; b=V1Rs5mqu7pR2x6J2uF7aMZQmiPf5eKe+vdVl2sHTs2DGjQVFGIQS155ExvVMTMbzfIiXbFWtLwq+TNMVhAwmAbV9K29Mrg0xmKbFDLpkV1csWiHtB/jRd6b7uNL7fOKEKA++WeqfzFT/SFIfGm0S/agD1AnKIPhZ9/ScoiFvWIaepZBzVkagd3N3nJHFCoafybtsFZfcLeJ3qLD3iWtEBL+mkdbW/y66MbJ1T88SCWvdkZTop0I2DxvFMC+Nu8e1dl2BPO1W0p/aDeB6ixjeX1YnqLuKQrlFmFOa5EQssYMubI2QuG/BI+EZH+pty1WgjgjykPeyRunfqmU0b2H8qA== 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=1eFOByyCoyroKu4xZeYyPYJ+1rLsJJTnNUjkE2PvVpI=; b=moddgmop0kWl1AEPdknaT8c/k7N3hmwvU8XnBh1mf7y9KgBgWdLQE6Kph/gsh+0I7yB5bOYBh/OEokuZLWbLAHefvEu46RigbSQn34PAb1PC0Kw8VBx3QW35fHz92asgMX3VT/UVooQTlKOQsqvkIEHgLzmF9ml8L+CvDnTbfnrp1xaLgDCJXCqsrYzjRuCDVHdtzkHwZQM1TQbnvcllq8GYq8q3YxYLZz9cVb01w/0trFMP/YlsNaHH+3VzMgKYvaySf2LYouStlkQxFwLVEJPuwHe1+xcnAzc+esZC2iLVJcko8V9jFrj4li3YikYX0AIjgNuVApBJrqE48JFZsA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from BYAPR12MB3176.namprd12.prod.outlook.com (2603:10b6:a03:134::26) by MWHPR12MB1581.namprd12.prod.outlook.com (2603:10b6:301:f::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5144.29; Thu, 14 Apr 2022 06:22:24 +0000 Received: from BYAPR12MB3176.namprd12.prod.outlook.com ([fe80::2d17:b68a:e101:4c18]) by BYAPR12MB3176.namprd12.prod.outlook.com ([fe80::2d17:b68a:e101:4c18%6]) with mapi id 15.20.5144.030; Thu, 14 Apr 2022 06:22:24 +0000 From: Alistair Popple To: Peter Xu Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: Remove stub for non_swap_entry() Date: Thu, 14 Apr 2022 15:48:33 +1000 References: <20220413191147.66645-1-peterx@redhat.com> User-agent: mu4e 1.6.9; emacs 27.1 In-reply-to: <20220413191147.66645-1-peterx@redhat.com> Message-ID: <87zgko9obm.fsf@nvdebian.thelocal> Content-Type: multipart/mixed; boundary="=-=-=" X-ClientProxiedBy: SJ0PR13CA0130.namprd13.prod.outlook.com (2603:10b6:a03:2c6::15) To BYAPR12MB3176.namprd12.prod.outlook.com (2603:10b6:a03:134::26) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 4d979ff2-0619-4678-10e7-08da1ddf23e5 X-MS-TrafficTypeDiagnostic: MWHPR12MB1581:EE_ X-Microsoft-Antispam-PRVS: 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:BYAPR12MB3176.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(4636009)(366004)(8676002)(66556008)(66476007)(38100700002)(186003)(6916009)(4326008)(26005)(316002)(66946007)(83380400001)(86362001)(6666004)(508600001)(6486002)(6512007)(9686003)(44144004)(6506007)(8936002)(2906002)(5660300002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?eGhLpirSLGqJEe/ZhfZpbCavQ9Ub+7oQDWjFLurNwEMlT8a+/CXdLNBEVFHn?= =?us-ascii?Q?lrmJLl/6CmoSprpy45taG9fILJ8ojDeBF8PzxU60t+WtGGUKotiXv8awEcyg?= =?us-ascii?Q?XbyVMuVCh0Fe0eN6k66rWIyXaydEUDQRvAPD6bIIp7JT93vV5Pe3cvJz4Ums?= =?us-ascii?Q?KsJtvx8o1qTWYuE+24ODxFseKd8C7CYkxyCOJAAi84qCczKzy8L620S1RHxw?= =?us-ascii?Q?CRsxoXR7plU5Xd/C0e1lEpcCAFcqmxn/+n4gYkUbduAW8we7pzTvF6QbW1ss?= =?us-ascii?Q?hpZSeRHYh8O2Jytz0EAj11sY4wv0Vqa02iYpXhx1N3vEOjLZ0T7aOYk+8Ucc?= =?us-ascii?Q?T56x3lsdr5JzbwUTJKfWhVJB0QvocwlLJxlqSKgwXBHM6Tde0SXfqLOAiRkf?= =?us-ascii?Q?cUF54RRBpnRuq18FIj5L/IJcQGsq66nmTFX5U0zMOlJA/tsert/LPhgh3apZ?= =?us-ascii?Q?ff9Dn1KX+Lpd8t5TR9RbxySvz+k+8KCJrp2rTo66e4bRF5wG6WgqHleH7LjZ?= =?us-ascii?Q?PgCEC1IIejNmFFQ5PUc8DmAbXMMkMT424Td761TNnz8RyOc5ee3WdwvSYYS1?= =?us-ascii?Q?Xg7WnzcJhwVyQgOc7gSuYKEhO+OzXypmDaSZGml5ZmSxsDRpGy26zbRlyljI?= =?us-ascii?Q?GyDBx/u7CPShNqHk2cHOpkMR9kQw1AkaG6ubmbSRSDLYciajI7+RmDbpwHsl?= =?us-ascii?Q?DlNyZNV/ns1UIqxAj1H1ig1+B7PPpD/b0kmyLoJrCGMWUgb5RhQ5kIH51ksq?= =?us-ascii?Q?eoE+03m1mzK0c4fbiPZLqLf4AKkC8QHjldFJAlpDhcTRiDTqayJaUlswCTPw?= =?us-ascii?Q?P7zBhEVBVEvx1GkJtfuBAmDJG3bUR/+0xjIVC6UX3uh9VxJIvoRa+njb96CB?= =?us-ascii?Q?SZqRVv39rqAgPKsSuSA9QYg2Ot4xbqOqpfTDceJsEOp3StC2buyBpFGE0iLG?= =?us-ascii?Q?JnEooFQ0RWSL9hWOCPtOpxLuvcFXC9vzZqwKVXw7VjUwc8UtgZN7JrUx0xdR?= =?us-ascii?Q?3VN4tv+k5d42vSH+NjMKY7T0qJsYWl9bGbWrw4y9ZrUKsdRjKyLOEbYhiE2e?= =?us-ascii?Q?NYYOs/FDXbouHkngyJ02eETG2hIyVpfX+qcZJYtyG1Vi6z0aK2vzPosiZGs3?= =?us-ascii?Q?CUzGqBucAo0GBC4M9Cx77iQy8Pep2w98qlz2Yxz5UC9r5EXniCRX91E/dXx0?= =?us-ascii?Q?e09zgslroge5ydRSQkipcXr1UBJZZk8TYT9FCjk96vEkJ9g7Ppehu2WaJdnD?= =?us-ascii?Q?yGujYRCst45AirajU8476ZuYJkyjwmaDn6oSvSzzOtF9zCHMpTAyihZ3j/bp?= =?us-ascii?Q?rQfudxYEi1I9h4A8ilkmPAXOiq+lTdzum2CeU5BrfyitS5RRW72sKm9M/s9z?= =?us-ascii?Q?dGT7/AIyh8HJZeFyWF2EOieGbPwkKqQA9Y8N7PZuCjhbvqZ5RL0S2iPhVXIl?= =?us-ascii?Q?hyajvUiI2jNH0Uz/I0dtQk2IoS5GMhb8UFGMBeVS9a+B6A1dB006fEA6Rj1o?= =?us-ascii?Q?U64CIJsMt5RCHdCzJksT/IEFbtu53Esc8xQC1DnTEB3bWkUsMNty2tM20PGL?= =?us-ascii?Q?dFftFvy6DIYZfx7K+mkXG/qxtth2+xaBBvqTj7/DHhsWyXPJHPTyYEHRO3Pp?= =?us-ascii?Q?2ILL6JMYzG8R785dt7WOIxPKd0mZnAd0SRcxR4f6sATWLgF+111hrWTS13OG?= =?us-ascii?Q?fL9pvrIDIcsBu0n3ekdldOgGBzwSr2ugbvKzMT4P7fNY/ZuAdXvKgZWlw+vY?= =?us-ascii?Q?C+AVf+d78A=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4d979ff2-0619-4678-10e7-08da1ddf23e5 X-MS-Exchange-CrossTenant-AuthSource: BYAPR12MB3176.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Apr 2022 06:22:24.5036 (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: seTmHwlF3LwruQs2iPiOYftW0o8Qh0QnoSMx8jjBKZMncc6ykqYs6m65ffb1w2/iQ5bdJNT9L1aoXTC8kM4lBA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR12MB1581 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-=-= Content-Type: text/plain Content-Disposition: inline Peter Xu writes: > The stub for non_swap_entry() may not help much, because MAX_SWAPFILES has > already contained all the information to decide whether a swap entry is > real swap entry of pesudo ones (migrations, ...). > > There can be some performance influences on non_swap_entry() with below > conditions all met: > > !CONFIG_MIGRATION && !CONFIG_MEMORY_FAILURE && !CONFIG_DEVICE_PRIVATE > > But that's definitely not the major config most machines will use, at the > meantime it's already in a slow path of swap entry (being parsed from a > swap pte), so IMHO it shouldn't be a major issue. Also according to the > analysis from Alistair, somehow the stub didn't do the job right [1]. I wasn't so much concerned about execution speed given it's on the slow path anyway but overall code size, which is one reason all those config options might be disabled. However in practice it made little to no difference as those config options already remove most of the extra code so I agree we can drop the stub. Reviewed-by: Alistair Popple > To make the code cleaner, let's drop the stub. > > [1] > > Cc: Alistair Popple > Signed-off-by: Peter Xu > --- > > Note: the uffd-wp shmem & hugetlbfs series will need this patch to make > sure swap entries work as expected with below config as spotted by > Alistair: > > !CONFIG_MIGRATION && > !CONFIG_MEMORY_FAILURE && > !CONFIG_DEVICE_PRIVATE && > CONFIG_PTE_MARKER > > (PS: this config should mostly never gonna happen, though, afaict..) > > Quoting the same thread [1] as above. > > Please review, thanks. > --- > include/linux/swapops.h | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > index fffbba0036f6..a291f210e7f8 100644 > --- a/include/linux/swapops.h > +++ b/include/linux/swapops.h > @@ -493,18 +493,10 @@ static inline void num_poisoned_pages_inc(void) > } > #endif > > -#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \ > - defined(CONFIG_DEVICE_PRIVATE) > static inline int non_swap_entry(swp_entry_t entry) > { > return swp_type(entry) >= MAX_SWAPFILES; > } > -#else > -static inline int non_swap_entry(swp_entry_t entry) > -{ > - return 0; > -} > -#endif > > #endif /* CONFIG_MMU */ > #endif /* _LINUX_SWAPOPS_H */ --=-=-=--