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 7C7E7C001B0 for ; Tue, 4 Jul 2023 01:41:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D95C928004B; Mon, 3 Jul 2023 21:41:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D4486280049; Mon, 3 Jul 2023 21:41:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BBE9128004B; Mon, 3 Jul 2023 21:41:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id AB835280049 for ; Mon, 3 Jul 2023 21:41:41 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 77D0DAFFF1 for ; Tue, 4 Jul 2023 01:41:41 +0000 (UTC) X-FDA: 80972227602.15.C075A65 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf13.hostedemail.com (Postfix) with ESMTP id 1702520004 for ; Tue, 4 Jul 2023 01:41:36 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=muf3ZxsI; dmarc=pass (policy=none) header.from=intel.com; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); spf=pass (imf13.hostedemail.com: domain of fengwei.yin@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=fengwei.yin@intel.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688434898; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dv855n9ZI4L+4Gnj/IKLhKxQ9RahuSYBgFk/OwHDeBE=; b=8kvz3KDhTFxZS9JlgKGIibI4hO45GyOcIF4RyKPOUqqNC6vbPbyfap/C2uSTTwvQHsyqdX Hwqfs0bBvOGj2RpKhSnyzMZLd7ThXD5j7TinYs6dzgSUgw13WGyETj6C3cDEZfUFrdDQw6 5IIUcycITqx0Ztl5uKRHFLD/aGKJRSc= ARC-Authentication-Results: i=2; imf13.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=muf3ZxsI; dmarc=pass (policy=none) header.from=intel.com; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); spf=pass (imf13.hostedemail.com: domain of fengwei.yin@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=fengwei.yin@intel.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1688434898; a=rsa-sha256; cv=fail; b=8a17BJcH4lFfMcC4lhgoDTrR9ULbZiBDHRaqzHl2ZDr6b5ERJI88TvEEoUWP5O59VfoDpY smF7e21r9ddGLibNz00ocUfwSHHTtgMGd+ozwstCalE8L5Z3IyGDsHlQqBITza/udnqo2c 17zNZ1fWGHSihprmIKHYRGI7TwpopsU= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1688434897; x=1719970897; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=+5+xGinDoOC+dX1hr31DAy+3hygUp36IsuwlQ0lfwys=; b=muf3ZxsI5c1Sp7fX9xxqzsxezk5kF+UiObwDHmdsAHej4jD4PNRRW1I0 2Hb6a5fysQ7l9vSsysG5xJSpVQ9Mygf1XdA61uDX7tY4YBcoAm7yS0YaI 3Da9iHrj2cKYJHJNh/nwxoHjmwUrhbdKLcdTUH/1p+J+l8PP13cijVbrT hffkThVkPp9vJFQ682s8dUpbqn3gsKCmWX0AfB13lsqaoMAgFU6E7I63J s2o8V9LuueDmxYln56EXu4AqGXE06R33cfxq+ChcjnT6DF8KuenteFOhG xF6ajQEidMr6WKYOARAk8ZBH9R16VlN+NS1RF8mGKzFYZDr/hgLwF6NQ8 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10760"; a="352832220" X-IronPort-AV: E=Sophos;i="6.01,179,1684825200"; d="scan'208";a="352832220" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2023 18:41:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10760"; a="863240045" X-IronPort-AV: E=Sophos;i="6.01,179,1684825200"; d="scan'208";a="863240045" Received: from fmsmsx603.amr.corp.intel.com ([10.18.126.83]) by fmsmga001.fm.intel.com with ESMTP; 03 Jul 2023 18:41:35 -0700 Received: from fmsmsx610.amr.corp.intel.com (10.18.126.90) by fmsmsx603.amr.corp.intel.com (10.18.126.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Mon, 3 Jul 2023 18:41:34 -0700 Received: from fmsedg601.ED.cps.intel.com (10.1.192.135) by fmsmsx610.amr.corp.intel.com (10.18.126.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27 via Frontend Transport; Mon, 3 Jul 2023 18:41:34 -0700 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (104.47.57.174) by edgegateway.intel.com (192.55.55.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.27; Mon, 3 Jul 2023 18:41:33 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=A29QJkA5YrAf21UhPoHHDWJXI3ZRZz5a6JfC65TN/mYxYxs/8rKrMUDE01ghRxoW5yJHxlsr/5xDFIX2H8OpOa1YShF2YQ2fa+b/x53NsVKGzPf7OOQZCwoOlxEKIDt3+775mJE19YiB/rziCHWj66KHh2beg1W8N+XYwqhO5uTFq5EY6T9bU2LvOZAqd6HCUnYG0BPjt6OWiqWtzMU2lRK8ZFiM5P58zKY3wFbevIpMFh16s7jd0DQUIzxxw5aSxDK4JtJ7o6rmafUiaoNHyF/ZHy1U6paYVL0SqrkaG9BjczfKnruAChAtnrgtmv7uU522CVX6Ur+g/KpQwIYs/g== 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=dv855n9ZI4L+4Gnj/IKLhKxQ9RahuSYBgFk/OwHDeBE=; b=ECMD10OqUC+hyY6Y7LVJAz8gejGiBk71xE8eHLv4e6bJrby6Q6cAEAA4zEJY6DbjYdHZWj5ekbDl7cGS40ZqQr4wvFkkynQkYMfyxjbDVp2XDqD7VjkpzUwf/T5ZmvSewchUPfhHU+xOzaXRJ/Ynf0zqYUaXlELN0Eh+OWipiuM+8gEChJJagNwT2HAvWnPWvY272ExivGAvIiy3PUXXC+4LgG1Bd8cOoO5d58Chac9lo5ROxNsFh39KSbZenDpcAxcXreGeN+Kjw426oPpEIIKy3wDfe8eKJKbYa7biFQPdPzCdcOp+w8Gn7IUDEnhG+QXF3szMtu5SPaoe9oc/cw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Received: from CO1PR11MB4820.namprd11.prod.outlook.com (2603:10b6:303:6f::8) by CY8PR11MB7265.namprd11.prod.outlook.com (2603:10b6:930:98::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6544.24; Tue, 4 Jul 2023 01:41:31 +0000 Received: from CO1PR11MB4820.namprd11.prod.outlook.com ([fe80::e6c7:a86d:68d6:f2f3]) by CO1PR11MB4820.namprd11.prod.outlook.com ([fe80::e6c7:a86d:68d6:f2f3%5]) with mapi id 15.20.6544.024; Tue, 4 Jul 2023 01:41:31 +0000 Message-ID: Date: Tue, 4 Jul 2023 09:41:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.12.0 Subject: Re: [PATCH v2] readahead: Correct the start and size in ondemand_readahead() Content-Language: en-US To: Mike Kravetz CC: , , , , , , References: <20230628044303.1412624-1-fengwei.yin@intel.com> <20230703184928.GB4378@monkey> From: "Yin, Fengwei" In-Reply-To: <20230703184928.GB4378@monkey> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SG2PR01CA0186.apcprd01.prod.exchangelabs.com (2603:1096:4:189::14) To CO1PR11MB4820.namprd11.prod.outlook.com (2603:10b6:303:6f::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO1PR11MB4820:EE_|CY8PR11MB7265:EE_ X-MS-Office365-Filtering-Correlation-Id: 115231a3-3560-4428-4211-08db7c2fcac9 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:CO1PR11MB4820.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(39860400002)(346002)(366004)(396003)(376002)(136003)(451199021)(31696002)(41300700001)(86362001)(38100700002)(6486002)(6666004)(2616005)(82960400001)(107886003)(83380400001)(186003)(6506007)(53546011)(26005)(6512007)(478600001)(2906002)(316002)(36756003)(66476007)(6916009)(4326008)(66946007)(66556008)(8936002)(8676002)(31686004)(5660300002)(43740500002)(45980500001);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?c2lmMWJYSUttTW8wc1JpN1B5NVZrQW8vRzdtanFaWEZsWUFGMmJQTXJZMG1U?= =?utf-8?B?V2I1Wm5SelgyN1E1aEJNK3ZoR29ZM3ZHaktZN3J5OFhYSk9lcjlIVnl6VS9n?= =?utf-8?B?QjBheWdJSVFIWEw5WGVUK1pPdStySFczVVdrTlY5L0k0Y0lBQnlIbENxZjg2?= =?utf-8?B?RStKV2FQb3h6TmxxV2swWGVGWS9xMndQWTROOFVKVXcwNHNLZi83YWRXd2Qz?= =?utf-8?B?K0tJOGMzVVQxZ040YzE1MVZvakEzbEZNblU5b1h0WHhJdzVtemhlWC8ybkFV?= =?utf-8?B?N2F1Y3lkNXZIbGtTRzFweWhYS2g4MmNZbE1MWHR5Nm9MZHBlby9YYVM0VHZl?= =?utf-8?B?Q1FoNkZNZi9TN1BhWi9keDB6ZEJkSExvUHh3WSs0WFNwN1ZzazByWjBIdXlt?= =?utf-8?B?MjQ5SWRVK2laZVJkTTR5cTdUTDRISjk5SFNHRjZoMUlYOWptSGgydVg2cXQ3?= =?utf-8?B?YmM4azZIdGg3VHdtR21Id0U5cytwc0Vqd2xoNHpSVXJ2SWlKemVweExlOU5x?= =?utf-8?B?L3BQQ1MvZkx6MCtuaDRabWN1VFh0NkNEb2NkaWU2ZFhFZ3NidTlhZTRlTC9N?= =?utf-8?B?ZlQvZ3E5SytMVDVsMGpqbEZaMjVwSWhCUnZweFY0eWcxcGNrZnR5ZVVOeVRI?= =?utf-8?B?aWxqZDFiY3pHR1VHY3R6cCtDeEN0TFFKdUJ0MXVBcG1RSnptandiVGVMZURh?= =?utf-8?B?RjNYV3M3bXNvYXNnTWUwbU5XN3RZQWZzYllXQTJZK3ZKczlaK0QvVTUyalQz?= =?utf-8?B?aFJteDhsNDd0Mkd4MGhFSVhSQzk4dklDRzlidUhBR0xaYzF0Q21KT29HKzFD?= =?utf-8?B?dWIyWHVpZExqbmxKTGt5bXFQNmhqM3hWdkhTOHdUcnU5ek1VQlZsSWo2MUlJ?= =?utf-8?B?bHA5MEFLUTE0QnNabWNkNi9VZjRqdmlHOUFuUTVIaGdzQm94ejZjWGlCejdU?= =?utf-8?B?cEEzN0pqd3FUZFJzV0xVY2g5dVpKTldZTUN1MHV0R0ZybzJDT0FLRWJYV2Rt?= =?utf-8?B?clpUaFpSNEpDT3AxOWxJZHM4VlFnRENqbUMrMFRrL2ZENS9IS3ZMS3BNQnUv?= =?utf-8?B?bXV1V2t1WFdwLzVUcTVTRXV0YUxBcnJmd1hLc29WNDlKV3Z2VlF4RE9nN2N4?= =?utf-8?B?ZXFIVEsyeVJ1elpleUEvU3cvSkw4TEZiS2hscThHUjJ6YktxQ1NhYVdvRkpp?= =?utf-8?B?WWovNCtiZjdYV0lCTi9hZmtxWUlnWk9QYzNIem1YUDFuZkE1dXowWUpBRmtN?= =?utf-8?B?M1Z4Y0NHVWFzR05KSHI0UTdBaVBORjB3MGNNZlhXNVhHRnhlQkhuSTRoand4?= =?utf-8?B?ejdSeWN0Z0gzT3libUFNRVJmZk5qUDdONGc5blFTaGI1WUNoYml5dVVJME1K?= =?utf-8?B?NDhVOVlJVWJZRlRvMEpqeGgxeG1zdTJYMk82RFQ2alRhZ2ppWDFReHdPSW9N?= =?utf-8?B?K01keFdKd3ZONjNaR1dXQnJBT0dBWnEzcEI0MEdJREJCTmFrdVIzMXlYbVVG?= =?utf-8?B?NzJBYVRjb1p3blhyZGEyalRPSWVFdDNNOVpaK3FzTm16VWVCd3gwODZPb3Az?= =?utf-8?B?TVpMNzJidmFqOGVlUmc5WlhyRlFzNmRBRUlDMkg5bFB4QWZSLzBnYXJRWlRB?= =?utf-8?B?M0Y1Y013OXRoZGxrWjc5S2pOY2QyRG4vM0dUTEcyTEtJWUtrczZidERZVGpj?= =?utf-8?B?WStnYnRkWUZtLzBZRkU0Q2JycUhyMlpScUJ3Q3BJMlVwYW0wV01lTHhhbU9C?= =?utf-8?B?VGF0SDUxRnJwMUx3QkJDYU9NU0NyRXkvaFBrU1RuY2JFVkdEeFF4NWwwWkRu?= =?utf-8?B?SmRWdWF0VUdDVFIrNkZTWHd6K1pUUW40SGE4MlV3SzYzL21XRzBLVTVhRVhi?= =?utf-8?B?cEE4MFhxWDVmQXo1Y1RDRDhQUWNreGp2SW14Q0xFSm9EdUJzWnBxOG03MmRJ?= =?utf-8?B?RTlrNmFnM1haSU5XZ1d4cUJVNmVrWTNRNnZXWjE5ME4xS0ZON3lVTThjd2FT?= =?utf-8?B?NlhJaFlDYjd1R0ViWnB6bWcwRnN2RG1qTXIzODhZNzBta0NhTkg0VTJZcHpx?= =?utf-8?B?R2pGemlvUzlSSk0zeTZuRjdidklVWThET0N5eVBWVGFQOXErcUYvcDJBbUYx?= =?utf-8?Q?xwDjTzi1fTWA84m8/uIWNqz6F?= X-MS-Exchange-CrossTenant-Network-Message-Id: 115231a3-3560-4428-4211-08db7c2fcac9 X-MS-Exchange-CrossTenant-AuthSource: CO1PR11MB4820.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Jul 2023 01:41:31.3001 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: I3qs5zf4GB0ndpi6AIEN8XuI/zK3M7iHaiKir3zKH4WP1lYAS5tGrFJT9bT3eqF48g+oGW4knjChFzO9XJRWzg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR11MB7265 X-OriginatorOrg: intel.com X-Rspam-User: X-Stat-Signature: f78an4gjwbypkzuyfj5tb7kbbg3zmx6a X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 1702520004 X-HE-Tag: 1688434896-823575 X-HE-Meta: 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 kZeHfrXW jPUh1akXBbboqIHuAy2vnUrz5B23CqO/b541fwftp3mkHf5VeDHUnBaFRbhtFHVXweV0A82TV7D+mLCtq3OhfXGlY6yw4PNXUhFeQz2eIuCPd6dNbOe9g3/FrfcYNtbZauGxKTg6qcgFX9xW+GRCu4/F+bmqwwRSifFJSyNzJDJgv2uyxNsQcS7gzKYNZWM8aG3SXoE8t8aWazg8qsSv2mPn4ZQXYPbVsbx3yAZ+YjCL1A8S74RjA99LdjNalAkVAu47bPHBwwjhsJ3UhhpBOaBM6fF5NyAAsEoE2ZlGKZ6Go3yENJ9ftlnVqjSBotvZEI2hiUTaibSHdrOQ= 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: On 7/4/2023 2:49 AM, Mike Kravetz wrote: > On 06/28/23 12:43, Yin Fengwei wrote: >> The commit >> 9425c591e06a ("page cache: fix page_cache_next/prev_miss off by one") >> updated the page_cache_next_miss() to return the index beyond >> range. >> >> But it breaks the start/size of ra in ondemand_readahead() because >> the offset by one is accumulated to readahead_index. As a consequence, >> not best readahead order is picked. >> >> Tracing of the order parameter of filemap_alloc_folio() showed: >> page order : count distribution >> 0 : 892073 | | >> 1 : 0 | | >> 2 : 65120457 |****************************************| >> 3 : 32914005 |******************** | >> 4 : 33020991 |******************** | >> with 9425c591e06a9. >> >> With parent commit: >> page order : count distribution >> 0 : 3417288 |**** | >> 1 : 0 | | >> 2 : 877012 |* | >> 3 : 288 | | >> 4 : 5607522 |******* | >> 5 : 29974228 |****************************************| >> >> Fix the issue by removing the offset by one when page_cache_next_miss() >> returns no gaps in the range. >> >> After the fix: >> page order : count distribution >> 0 : 2598561 |*** | >> 1 : 0 | | >> 2 : 687739 | | >> 3 : 288 | | >> 4 : 207210 | | >> 5 : 32628260 |****************************************| >> > > Thank you for your detailed analysis! > > When the regression was initially discovered, I sent a patch to revert > commit 9425c591e06a. Andrew has picked up this change. And, Andrew has > also picked up this patch. Oh. I didn't notice that you sent revert patch. My understanding is that commit 9425c591e06a is a good change. > > I have not verified yet, but I suspect that this patch is going to cause > a regression because it depends on the behavior of page_cache_next_miss > in 9425c591e06a which has been reverted. Yes. If the 9425c591e06a was reverted, this patch could introduce regression. Which fixing do you prefer? reverting 9425c591e06a or this patch? Then we can suggest to Andrew to take it. Regards Yin, Fengwei