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 08CD5C433EF for ; Fri, 1 Apr 2022 19:26:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 73C4A6B0072; Fri, 1 Apr 2022 15:26:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6EC908D0002; Fri, 1 Apr 2022 15:26:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53FFB8D0001; Fri, 1 Apr 2022 15:26:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0151.hostedemail.com [216.40.44.151]) by kanga.kvack.org (Postfix) with ESMTP id 464606B0072 for ; Fri, 1 Apr 2022 15:26:00 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 1092E182CA11B for ; Fri, 1 Apr 2022 19:25:50 +0000 (UTC) X-FDA: 79309290060.22.FC9BEB0 Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10on2042.outbound.protection.outlook.com [40.107.94.42]) by imf09.hostedemail.com (Postfix) with ESMTP id 3BA11140033 for ; Fri, 1 Apr 2022 19:25:48 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=K4mQbq29hatKinCYo6A4FHUNEpXSd9ohrQXmy5o5+qjwPjGJPLLgIW5ZnrK21aURX5PeHV4IhG1c6eNMGn7efPvxKbU7cs+QNqWd2qWz9AkVre86ZExDwKxgToUYKx8pHhouId2dgN2LTo2Yu2Yoqyej5EEXyYDoDY9WCQ9vfPJa1l05ScUkWcUq1W3Ti5jRwiCtLjt2LWorQV2P6jyTIVPo1z8723S3ezR4S+T5nPoWq7Iivc7jDk801YRqCd4ff+To3D77eoASxajNXMV7CtMW+6oXyLCUmRn//nsJ7WMzGgd5EgeDqfMhvDHig3K2QV03fQCHB0x80iJK/8nctw== 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=CGdQXqackUu/7bV8DyPYZNikxqAy3IP4UwbA3CWPU/s=; b=Xw0AkmfcMd0A/614mm/VgOi8BYJZ4b7B7YLfJ7AOI3RUqKTGDhHRRUBWSPDqgZBk44DYwkB8ubaTo6Ckmcc5o4uCGbGJtMFMfXAyUwAIl41pRAXKd0r0uTJQbcgV0FTHveai2vqZEEGTB9ew6XartITEWQy+hLaevtU76gau+zFDT+HnXxFcrhYmwc9O7u9Gwl3vfHqOXupowz7FqJqmo/eWMpkQc8c3aNFhqYtVGnyW0BOgMV3Kef8ybSs/uSt2aMSZ1kZMDZh2IJWWWBhKTIDrPiaBUneW3u+MV2nDq8K8Ic6J10PhMU4Pud817RKFMietCra05gVZKcBqctLztg== 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=CGdQXqackUu/7bV8DyPYZNikxqAy3IP4UwbA3CWPU/s=; b=hbIDbfvuBitZZj7FuZFQGXyE5WkggDIG2P4o4EsTAgQODUwLwTbPhHB30JnJdROIXwsruFA23nRDV4M5vJHZN35OmzUk4gjkbU5y9wOusS84zGBQ8SGrzI5KkOA+dZgow0n6JD0pFSd9lXBqRtrEAEJnpdt4pXkSw49w6o71yufi4HbbSDo6gIBLJTXdY8Q4Ehr47J6eQsmLm0mXIsazeKm+qQJZndNAScrGu+nBZpB5Wt4A4tTvyq9/MsmKTU6rCT/Dn+OmLtAk44FzTZYoc0o1GG/OCEdHTLui0vl9mPI1qDIgcee3IdL+8ve7Uju/1gIeiqwnPMAwdITnDq6bPA== Received: from MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) by MN0PR12MB5979.namprd12.prod.outlook.com (2603:10b6:208:37e::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5123.21; Fri, 1 Apr 2022 19:25:46 +0000 Received: from MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::69f1:dff6:826b:7d9c]) by MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::69f1:dff6:826b:7d9c%5]) with mapi id 15.20.5123.025; Fri, 1 Apr 2022 19:25:46 +0000 From: Zi Yan To: Linus Torvalds Cc: Linux-MM , Steven Rostedt , David Hildenbrand , Vlastimil Babka , Mel Gorman , Mike Rapoport , Oscar Salvador , Andrew Morton , Linux Kernel Mailing List Subject: Re: [PATCH v2 2/2] mm: wrap __find_buddy_pfn() with a necessary buddy page validation. Date: Fri, 01 Apr 2022 15:25:44 -0400 X-Mailer: MailMate (1.14r5870) Message-ID: In-Reply-To: References: <20220401181109.1477354-1-zi.yan@sent.com> <20220401181109.1477354-2-zi.yan@sent.com> Content-Type: multipart/signed; boundary="=_MailMate_69019D90-B67C-40E6-99F6-195971470BFC_="; micalg=pgp-sha512; protocol="application/pgp-signature" X-ClientProxiedBy: MN2PR20CA0057.namprd20.prod.outlook.com (2603:10b6:208:235::26) To MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 051f68bb-1a82-4e5b-73a0-08da14156bb8 X-MS-TrafficTypeDiagnostic: MN0PR12MB5979: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:MN2PR12MB3823.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(4636009)(366004)(186003)(2616005)(38100700002)(26005)(83380400001)(86362001)(21480400003)(54906003)(6916009)(66556008)(235185007)(5660300002)(66476007)(316002)(6486002)(8936002)(36756003)(2906002)(4326008)(8676002)(7416002)(33656002)(508600001)(53546011)(66946007)(6512007)(6506007)(45980500001)(72826004);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?uEanB9Db4rxq8Xio7tmKystVOHoKZm98S9aPLcGXoApS8xJK5AcUuCM6lws3?= =?us-ascii?Q?RoGnZBao+bPKO5CgNZGerpBYUDEoAO1pz6qi3suP4bMUKqOmAaolnkAybib6?= =?us-ascii?Q?f4hn1/uGt5Uq/CfFOwea0cmn6X6G2F3H3/lfv1/2buD/EvY3tTU3N7UEbbNV?= =?us-ascii?Q?MOzz6uEfiIcP/hxzZDxJU2TSd2NUv4P7/v/m7uLCktPpmfNcEF+TTULPOA/V?= =?us-ascii?Q?ia1Mkxj0Hb83fYBLFJ5rEMOhKcB13DjrGwlm2NPlHBsUuV+1K2lWgrZBQ+wk?= =?us-ascii?Q?sBkzyALSreXrx9awUKit6sSuQL/wiqqViMh24u7NqwO9/T8suWv0ryNi9B9n?= =?us-ascii?Q?FhFZ0fWJ4DT4jFHduj0hLDM5SRbzL2dZjUamz3+QrpRpuDbxXl9CKrdIxxqX?= =?us-ascii?Q?xhXrJBpEhGZ24Vts45QqVCQUVHWXoBstFm/0zkaD9StoWxMNaTAOAfqG/kgJ?= =?us-ascii?Q?K9x0XpiKxap2nfl90R0d16S54LKs1gvuTa1byqN5KGzPH4MAEPKoJQb43QmS?= =?us-ascii?Q?I4GFL2ZFOuJUEg7+UpAJo0KsOMo3EvU6yLUbPPhbaeB4ZOMvI+sY3QBJCaA4?= =?us-ascii?Q?l/xSzbAJk6WmsrgrvXHN5PeiIJM9WjpedraJQKHPK8Q/jDEHV+s5x0G9Crwk?= =?us-ascii?Q?jGJJ8J4jeSxfjXr6t6V1X8F4ocdFIU4uYCTS8bqM8xWI8rhiUyWCjnEutEVI?= =?us-ascii?Q?2qT/3Edr4b6wy23NgPwCAvHAvejqrWzBo9GcYQAh1UknceXalvIh5lzTOUNu?= =?us-ascii?Q?fZVP2w30tyya/BZC4k+7XazUy506s02RxEH51d8wyV4UbiCr7ATaTdHwQbgs?= =?us-ascii?Q?7CYYf9CXP07A+Ft0sYo/wTk3RdyfwPlyA9mRcZi7jue+v7cHHFsdkYsUk1mv?= =?us-ascii?Q?9wZ/Bw9Yxo2mjJ6vfT6iRsJig/52cJ6K87Bh3Nbk1iHUqJncAdb6ay0BON7W?= =?us-ascii?Q?ETLfaP3w0RsCLMml2WcigAspzLV4Xqn1/wfpX3Hm9L0fhh/GowhXqzNDIyBq?= =?us-ascii?Q?XrmlHXdg2mnTrgmIjfpDc/xyhM8xAF12WdgMSwZgI5mjDaWIViVWR1jGJ7R/?= =?us-ascii?Q?CZmzDhCNZJMn/f20XBAI+kiA5PfmuP4OSs9T5dxOquQxJ4QDuzlay6xXIoE3?= =?us-ascii?Q?3Zf1WN83YXcc4ud33gfQWur1bV0iFzzJ0OxovWAuv/T2otY+A89Ra5uTBe7N?= =?us-ascii?Q?r1G8t3zznEwxgKu89BOj5d5irVFfFSzaL5H7n8qw4pJE3efUQmCLmCJ2Wxei?= =?us-ascii?Q?EPjcaMLotRn0ErhGwzMSoTROaEilIY4DuRijUkMi4zJTqikWGHUzX7QK+3WN?= =?us-ascii?Q?9QyvFPbpilQxeooQPAgZo16s8jrxLoZUj2XLvxJNdOME5I/QAsiuDmnEhg2v?= =?us-ascii?Q?hvc7T4Gq5P31WFAPdaRiPc9sQ2N5mvnOGyNFNWZvE9WOw4GAwnMY8qOqNUwY?= =?us-ascii?Q?jNaIpmgRyTzH/NutGhlSocuBJg4Zms/6em32ahkZYUlX6QEdLQ4gsYtNC+iT?= =?us-ascii?Q?NifKBjBfnPMQ8vGTRZcj19Gf1UgP+e49mzbd5O5bnoH5cR3s1DjC7DSu0lxg?= =?us-ascii?Q?zCaS3X5q2eT1mcfe1O0y88uNIk0uZCCQv5xSIjJHxGBd5mQQPhXLx5WlWkaY?= =?us-ascii?Q?alHBxNOYlwOOcM1UDKo2JfbdTmyq7rcwiCpNW2ffQ4rQXliTLHc7EH3NzwI7?= =?us-ascii?Q?x6DdRukA5Fl1q9Rq7rBpPvcRsu5xsDXBTYkpbcHDrYz4U0QydthfC5/f2Zwo?= =?us-ascii?Q?6bvqo9DanQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 051f68bb-1a82-4e5b-73a0-08da14156bb8 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3823.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Apr 2022 19:25:46.1559 (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: 7eoAdrolQ3fz8XCozBTczCt0wDYAYHYagu6Mpx3ejV2Yu+tLJMlySZrZk2sG1Kat X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB5979 X-Stat-Signature: gpf3pcmcn88d8c8yye3aampk8meu38kz Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=hbIDbfvu; spf=none (imf09.hostedemail.com: domain of ziy@nvidia.com has no SPF policy when checking 40.107.94.42) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3BA11140033 X-HE-Tag: 1648841148-441516 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_69019D90-B67C-40E6-99F6-195971470BFC_= Content-Type: text/plain On 1 Apr 2022, at 15:01, Linus Torvalds wrote: > On Fri, Apr 1, 2022 at 11:56 AM Zi Yan wrote: >> >> How about the patch below? If it looks good, I will send v3. > > I can't see anything worrisome, but by now I've looked at several > versions and who knows what I'm missing. > > Making it inline and allowing a NULL 'buddy_pfn' pointer for the cases > that don't care might be an option, but I don't think it matters > hugely. What do you mean by inlining it? Moving the function and __find_buddy_pfn() to mm/internal.h and mark both inline? Something like below to allow a NULL 'buddy_pfn'? buddy_pfn is needed to store the result of __find_buddy_pfn(). The code does not look as nice as before. struct page *find_buddy_page_pfn(struct page *page, unsigned long pfn, unsigned int order, unsigned long *buddy_pfn) { struct page *buddy; if (buddy_pfn) { *buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (*buddy_pfn - pfn); } else buddy = page + (__find_buddy_pfn(pfn, order) - pfn); if (page_is_buddy(page, buddy, order)) return buddy; return NULL; } or struct page *find_buddy_page_pfn(struct page *page, unsigned long pfn, unsigned int order, unsigned long *buddy_pfn) { struct page *buddy; unsigned long local_buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (local_buddy_pfn - pfn); if (buddy_pfn) *buddy_pfn = local_buddy_pfn; if (page_is_buddy(page, buddy, order)) return buddy; return NULL; } -- Best Regards, Yan, Zi --=_MailMate_69019D90-B67C-40E6-99F6-195971470BFC_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEE6rR4j8RuQ2XmaZol4n+egRQHKFQFAmJHUbgPHHppeUBudmlk aWEuY29tAAoJEOJ/noEUByhUUA8P/1qa+fY/px0QB52oAWE4M94HpiwDAF0jZ4Ny JuNNR/vPNhcQjCFuznKLli9oWToXnUR8AN6DUB/g0cr5dYbq2Q6Suasz9chcKj0b kMOWMcSblEAmsKUagX0ROcD+oVzw+xg8Bhbp46AKKeDuLzKCPT/RPRp66KWau3EU jSO6sLZwroe+JEFB7M15sU718gS7HTlRg5hwmYSf1OhbR/3caRq2mb0fAAvcoq25 ognb4rp/8oOg1UvDilhkqwLyItbfB4aajOENc1tUvbkbz3sgJl+sdQ0z5wAOO5xU /uxWb1eppl22kFYCLD+7ZXhrSwlSGomWzpIjSG9ZhTzZDgUGpirO/Rze14i5Y/+K u2rQNAlNt510rDIMHhZHUWbLXhWLLRL4YkbM70gq2vzicRJV6AHm46m5oiqbTCaR oMZmSbnLy9v94vpAISigx40oz2GBaEbBFZ267I2sPEvdsRaJGEk+WToNdx/jrf+w B3AuZYd/SWpwduTNrjzGCDHEd33tsEqOrFvxL08jyUYg/cGI8ngF/ZJJrbGW/LFs +CCW2Ho1aoHts/00qNfowLKuBxHTSv0SUe/wnm0VGi7DHWXKm91K7yEz0CCjFhr9 J7yZ3YOg0uJ8tK9jikUrYj+cPKwKrqa+i4Xl5IAZbhwF5Gi0zp+ZB7yMtr5BYIcW bSMWiLJy =4QJu -----END PGP SIGNATURE----- --=_MailMate_69019D90-B67C-40E6-99F6-195971470BFC_=--