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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 738DAC433DB for ; Thu, 11 Mar 2021 15:52:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ACF2F64FE7 for ; Thu, 11 Mar 2021 15:52:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACF2F64FE7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 023418D02C8; Thu, 11 Mar 2021 10:52:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F3DFE8D02B2; Thu, 11 Mar 2021 10:52:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D90528D02C8; Thu, 11 Mar 2021 10:52:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0082.hostedemail.com [216.40.44.82]) by kanga.kvack.org (Postfix) with ESMTP id C2B8A8D02B2 for ; Thu, 11 Mar 2021 10:52:34 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8903F4DB8 for ; Thu, 11 Mar 2021 15:52:34 +0000 (UTC) X-FDA: 77908035828.15.2F3E119 Received: from NAM02-SN1-obe.outbound.protection.outlook.com (mail-eopbgr770057.outbound.protection.outlook.com [40.107.77.57]) by imf06.hostedemail.com (Postfix) with ESMTP id F09F1C0007C2 for ; Thu, 11 Mar 2021 15:52:33 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Br4FhzLL2M2CKKYo2vzwkZ/sHDnei/zJIII1UD4jprqypGu+avLXgog1bnFK9HwTVlqlUbCxxfxi0ilQYzLRkuHnEVwk0By7YswpjJD8Ase1vuNps9JOnFHsfN4k7oqhuChAmg25MG+13aBHt+birf4txwuW7DeBNTyn4HfYKe86h2MUjjZsx234E81P9g4m1NnIB5pOSVrw3W6X+wsgpON1VoylkBIWRU05uozlgSJoOahKmDsuwDCslVSg+z+y7fOgHKXmSZIUtPD1U6AgAW1aLxNNOj3ZOTDljpmNDpvAUacmnFtykQbAsGmB4pqA/naFiEW3qIKh1Ax6iJ5fQA== 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-SenderADCheck; bh=gQBqN8/Hjka9Q9Y9C2ifg8Vk0pcyecrhhHNnWBzmUIg=; b=dx3KyHGTw5tbTvJhPeyV1uN3KsPPVQJBln1kWOpVCxFJmOV+TgYLi+R8DiZaZwUJt5wcDXpg8VedI2brnBFqORuB12X/CHv8a+GgcIxCVJTC7voIzf0krg2nP5XYVEZfyUyMsFJwewJYYv7ny8lhQNgpBE/iWjWXR7UBstWkQRwxk+8Fz0PSc4gedqJgTH9QY2UG8Wo77VydGhlwQcOU5m+6FjX1NRx+fIfGoRmjWZOkpF5fnskVlng2/98E3tiwOjCRHTi4vuqcluHf/e65oTwIwDlxqbOaoSz+Z9rUGYTf7gu7LrXCISfFXOCtQ0fqHerIfrsIxz6EarD0vY1O9g== 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=gQBqN8/Hjka9Q9Y9C2ifg8Vk0pcyecrhhHNnWBzmUIg=; b=VhJQnZSly/Lu75FNjpDKSPuSDdCblCE9UKImSlE3Mh/3WQF+ODg6B6/AWg9CGR6vGA5PELUdOL6Y9BA1NdEWFwgZdsdrJigihJWQEQ8JgIGi+sjo2GcBVhLdMxA1xVkI0xAtsa/FcSAW2BwyXEnorWXgNf+DnSZ2dfNk7tpOzxvIy78hhRT8NVRgDvK83nQ3eH2+Df6mNIk+QgQUl/uJZheACgFEaueEuFpbV6xA0a/SSLl/zEgkIsWY5q+PE7uhu7gPmXdnVlX1dQRXgAEeQKUIX8INAbyPz7N/B8CE10LsHM+lVrI1EuCLsbCvBDuoEP/CcBTG7WXTTpC/uW9gHA== Authentication-Results: gmail.com; dkim=none (message not signed) header.d=none;gmail.com; dmarc=none action=none header.from=nvidia.com; Received: from MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) by MN2PR12MB4798.namprd12.prod.outlook.com (2603:10b6:208:3d::33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.21; Thu, 11 Mar 2021 15:52:31 +0000 Received: from MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::a1b1:5d8:47d7:4b60]) by MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::a1b1:5d8:47d7:4b60%7]) with mapi id 15.20.3912.031; Thu, 11 Mar 2021 15:52:31 +0000 From: "Zi Yan" To: "Yang Shi" Cc: "Linux MM" , "Linux Kernel Mailing List" , linux-kselftest@vger.kernel.org, "Kirill A . Shutemov" , "Andrew Morton" , "Shuah Khan" , "John Hubbard" , "Sandipan Das" , "David Hildenbrand" , "Mika Penttila" Subject: Re: [PATCH v2] mm: huge_memory: a new debugfs interface for splitting THP tests. Date: Thu, 11 Mar 2021 10:52:25 -0500 X-Mailer: MailMate (1.14r5757) Message-ID: In-Reply-To: References: <20210310153544.434160-1-zi.yan@sent.com> Content-Type: multipart/signed; boundary="=_MailMate_C7BC74D9-ECED-4338-B45D-2E12B37F2167_="; micalg=pgp-sha512; protocol="application/pgp-signature" X-Originating-IP: [216.228.112.22] X-ClientProxiedBy: BL1PR13CA0271.namprd13.prod.outlook.com (2603:10b6:208:2bc::6) To MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [10.2.49.51] (216.228.112.22) by BL1PR13CA0271.namprd13.prod.outlook.com (2603:10b6:208:2bc::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3955.10 via Frontend Transport; Thu, 11 Mar 2021 15:52:28 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 28cfe522-c927-4f86-4833-08d8e4a5ada3 X-MS-TrafficTypeDiagnostic: MN2PR12MB4798: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-MS-Exchange-SenderADCheck: 1 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:MN2PR12MB3823.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(376002)(136003)(39860400002)(366004)(396003)(346002)(83380400001)(66556008)(5660300002)(8676002)(53546011)(66476007)(54906003)(8936002)(86362001)(2616005)(26005)(2906002)(6486002)(186003)(16526019)(36756003)(956004)(235185007)(316002)(6666004)(66946007)(33964004)(16576012)(478600001)(7416002)(33656002)(4326008)(6916009)(14583001)(45980500001)(72826003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?c2YzSWk4anloRXU2STRQc201bWFCYS9lTVp4VmdVcG40Wm91MnIvVFc3MEhW?= =?utf-8?B?aVJyekE4K0Y0Q0txOUs4S1hnR2lCM3ZidGFHUnpMUXpGVFBCRE1FaXVxR1B6?= =?utf-8?B?SDZGNnQwdE1ZSk1iN2ZYUDFIWlhiMHVmVFlvS3FJQ0xLMmtZUDBOR1J0bFR3?= =?utf-8?B?aWY1MXhDdnlscWIzSGlVanNoc2tLcGdQMVVuRGQxTHd3dGpMTUo5UEpLUkxI?= =?utf-8?B?RjFGTXQrQmtEOTNCdXlDdndpUXdFOFEyUjN0ai9FR3JEYzZxV3J6QjVaY215?= =?utf-8?B?cUpBVzVzSUR4M2h0WlJnR2hGOFV3SlVrSDU2aFlxMCtwWU9OQzg1azJQTUVX?= =?utf-8?B?U09kaW5qdGJrSkxDL1VteTdQM2MraDM0aWFKOGN4MEM0OUVqY3JSLzdoWEhB?= =?utf-8?B?U1BNRjRnSkZUSnFJQzRtOUZvYUQwN3RJTDBEa2VtYU9oS2NwdDhXcG5PQitH?= =?utf-8?B?TXBlY3p0TlBGVkxPekJ1K3c4T0JUK0pXSnNZZEhtRitPRkExZ1QwVmZNNVZV?= =?utf-8?B?UnNUY0pReUZJNEZzMmx6RklQamZWdDlzTXV4NXVaV1pKSVl3YWtSVTMzL0F4?= =?utf-8?B?YXhGdFFZQWtnNWVXWmdwbCtBbUtxbUNWUU1INmJPaUE4emlFSmVLcHJFR0NC?= =?utf-8?B?cFBlaGxsYThVZGMwM0NacEc5amVBc3FpWjBmRnFyZHFQM3duS0pNdmducHY2?= =?utf-8?B?Y1AyWEtFeWVYRnByb3RZTC9QSVdGQzJtTGcvR0xOMEZyVXB5NWZDZ1VWdDFJ?= =?utf-8?B?WkhoWkU0QUxHcEoxdG1MSTRiNkVXdlJWTFlzQnpiWU9Zbmp5ay81d2NQZ2RV?= =?utf-8?B?aExIZDQ1ZWI0QUNpK0hSWXZhMWppY240cG90VDVhbUV0Vzl4d0tqYVRGM1My?= =?utf-8?B?dG93TkRLb2ZZcFcxZDJFd0IwRklUNk9kRkhDL3NtVW93aHdHbXkwaDN5MEFX?= =?utf-8?B?V2V6UWZDUzJaaUN0Z3B3eSswaExSWXhaZCt5RGZxVUZtc0RhYS9XdHZwSFZn?= =?utf-8?B?eWVHSkhFZkh5R1R4TzloeUxKek9qWkhEY0dPcWhxWUdTbmZ3RUp1R0hYYkN0?= =?utf-8?B?bWRDbnI0TVlDWEVYTHpmYXBYdWR1MkFzeEFhbG1KWThlaUoyVE0rOGlaMXF0?= =?utf-8?B?VldSVU5uUWFydVpNS3NPMWlqZm5BVnkrSVM1NmdlQkdiS0ZtYmZKTE5FYXdz?= =?utf-8?B?Z0dTWDRwRFNUenVqQVJERnlzbjJVOG1xYUxMY3NXa1IwVERacEtUS2NmTXkz?= =?utf-8?B?a0wreDRVSk5DR1NkaEl3OWdtZFNSM2hPS3o3c1dqWWFXTjl3MHRsTFdTVzV2?= =?utf-8?B?L1NHbFY2ZkFmWnpRQ3ZJSS9lVlZtMkw4eFVkcGdiMXQvQXhTa3ZwWC8yNktS?= =?utf-8?B?Wm01N0Z2dElqb29vTUJtMFErSFJERWVVaHgyUVRWTjl1K29XSTFQMWc2TUtR?= =?utf-8?B?ZE9jb2ozSlFUNDVMcDA5ZkVqS3ZsNURoNms5ODNvbTVkcG5DZXFUZkJoWlNU?= =?utf-8?B?OGtYYVI1aDZoZzZKUnd1THg2WlhBdzNCUHU4QWtLVTNURlFXc0FiK3JXZ1dB?= =?utf-8?B?NWlMdkNyS3MwNHNFK3ZYdHB0Vm94cmE2Tm1DczQ5VGM2UEF0V0NuMThlSlgw?= =?utf-8?B?NHdBWEJ6eG1aeFZRSk1ObXV5MGtPRlR6RDMwR3NtV3d0M05GYWRKenVkcm9p?= =?utf-8?B?elZuaDA1RW82L0x0bUdMKy9qcnQvaHZsMStrWUpZaWZVRFhkOS9JM0djZjJZ?= =?utf-8?Q?NHZX+YT0lw0Uw0WFuIUVIJ+zGKbli++dwCp1kSZ?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 28cfe522-c927-4f86-4833-08d8e4a5ada3 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3823.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Mar 2021 15:52:31.0289 (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: OW4mVRLvEbqPQMZiGzxdnyhlTN8FMP1QRXKHRdGFCTook+1GkHY411q8itwEDq3m X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4798 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: F09F1C0007C2 X-Stat-Signature: gyowm44nnkyc8jot48jf15xgsbggdsy3 Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf06; identity=mailfrom; envelope-from=""; helo=NAM02-SN1-obe.outbound.protection.outlook.com; client-ip=40.107.77.57 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615477953-842592 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: --=_MailMate_C7BC74D9-ECED-4338-B45D-2E12B37F2167_= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On 10 Mar 2021, at 20:12, Yang Shi wrote: > On Wed, Mar 10, 2021 at 7:36 AM Zi Yan wrote: >> >> From: Zi Yan >> >> We do not have a direct user interface of splitting the compound page >> backing a THP and there is no need unless we want to expose the THP >> implementation details to users. Adding an interface for debugging. >> >> By writing ",," to >> /split_huge_pages_in_range_pid, THPs within the given virtual= > > Can we reuse the existing split_huge_page knob instead of creating a ne= w one? > > Two knobs for splitting huge pages on debugging purpose seem > overkilling to me IMHO. I'm wondering if we could check if a special > value (e.g. 1 or -1) is written then split all THPs as split_huge_page > knob does? > > I don't think this interface is used widely so the risk should be very > low for breaking userspace. Thanks for the suggestion. I prefer a separate interface to keep input handling simpler. I am also planning to enhance this interface later to enable splitting huge pages to any lower order when Matthew Wilcox=E2=80=99s large page in page cache= gets in, so it is better to keep it separate from existing split_huge_pages. =E2=80=94 Best Regards, Yan Zi --=_MailMate_C7BC74D9-ECED-4338-B45D-2E12B37F2167_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAmBKPLkPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqK/4QP/1dxavX0w0G8RD5iVNwQfkVgpLAkZDXieitV 8AdDwks47bew/sDhj7CC4TrdESB3+kPMFDE9Bwon/bpj7j6TDU9oWUYknLjnIKwY slML3JTh/0Sv/17vkcHpE77ZIPv/GI+Vs5y+7Et1TXNpA58BV7N2gB7GpbymDqvL 97idRka5nIUsi7ISTojMZz+zZ272LELkgffIJZzNBCO7l23w06yUWZ0AL7GN7AFm TJFESftRYm2eZOwwBlkpE2pzoyAsBS9w9QantpS+zLgd+f0118zzrPkUVlwMAn+w ZRWIg29RJGtQuG3aE4ODOvbUSf8P7L355hbTKeE6QdPPwC9qz3JpUayC5krWPstq J0BO2CNI/in+qKA0ONg8mH7ae83LqqRzzjfu5maMDZQoT/WCBz13U2rJ54tH++Yn TFzudCSSMsryvyK28jjLgiw8APLS24LPIORKJq6cplRHyOOKO5pT6BP4TIWsvzox XU9cSqfp6aOT6DVFCNKhdoOTGJN+i1/V4ToLjogikGVf7TV2kDqVAeZ7DV93jxof hDBkUXUYz5zNq4E8zTQ+0coTyfIcvNjQ4ziVQpkmQ4B/Ch5uo8+M861KjNzzfnKl m2M607vrJXU0RqdcE2O+/yotBxQ4y3ok0qHDIYT6QOPePX3WdVEU9YRHd+cvVJdX Pf7pzkjK =c6PJ -----END PGP SIGNATURE----- --=_MailMate_C7BC74D9-ECED-4338-B45D-2E12B37F2167_=--