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 94F1EC2BB41 for ; Tue, 16 Aug 2022 07:13:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231892AbiHPHNI (ORCPT ); Tue, 16 Aug 2022 03:13:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231689AbiHPHMs (ORCPT ); Tue, 16 Aug 2022 03:12:48 -0400 Received: from NAM02-DM3-obe.outbound.protection.outlook.com (mail-dm3nam02on2062.outbound.protection.outlook.com [40.107.95.62]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E74AD1C4740 for ; Mon, 15 Aug 2022 21:44:02 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=k9V8vnI7dI15dFEjyvqQYQ7dbNumlSC6J/1CUOYavrCOqKHINB0ml1W1y9i3LfomjEAfxo4efG0+iQCN5NsONQXZFQWC0QdaBfiW5rlHdLKfuCpfoc+7u9N03EIpZq3XctD3G/MRdubVBHqxl2bhX3oXYu1HSauxny6oV/SlwdHm7FfsWwJDgZu5RRbaSYBtsw2gG4E+6gRoRMs+XWjyPssiSo2VhB875XzyJlN3s7LDG9grv+h7xY3yl8+d27PP23Jxjwas7qqzeF7FTwf2tSLIRfhrYdToVyrBNKuimgCsIQwa6qPeunp8p4amVG73cu093k3Bem9L4yT61EHRbQ== 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=x67OEHyAO7q+gFvLoWKxmzFCxqFJj3vLmYZA6bdvwSs=; b=J3iqNFGqJWM9B8fWrGig/J4opZjiLEabZMRIj15EaHy68bti92d22Yrh/Jyr+FTTNcYmouJQ45H2orDiGOaSOoNwiT4QLyOt8IwBzggLzJa6rc+2gkq8f2TAy4tQLDuw/KLpXbcN6V76f91u2Lo9/TU1QTkfLJURUOLYR21QQleUZglvdEg/2tA4QuWGjvxjs9yceyjDZWFFOYmg2pH8oQ180wTaCY9zNFUCeJwoOSciTF3iNqhIzf5AwiUhALx5jgIhJsL5Wuf9GIHXP4If25JlDg7gr3wH/KEbuNRHW+7DDIVheUz53OiRZLQhGjOxSFPRZZxxUoH7LT07tbDvRQ== 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=x67OEHyAO7q+gFvLoWKxmzFCxqFJj3vLmYZA6bdvwSs=; b=ryzD3nL5XVDZOUldzMBp1d7vinNUCBjAxmgJg9KxugYihzNk2LIZeERJ4YGmP60KrMYo2ex91IZafhZCO3FahMri6cZvQtCWcuBMHVHtKZY+P3E2iGdK2TmwHZ/AqzpCENE4b/Wsal9VdnB6qAM2iNX4xgzPkx0qGYiTZlQh8SOYDLsqLekjQNP9cuOo6LP5VZHom2QcjnENumKeKyVf63AdLZWH0EUAvv/Cl1kRa8fpxT/YUbahCOKl/dM0g+A0Bx4xCxzM99d7LwYrcamNZtL/bhVy2pT5nnkesdydkcKYPA7fOp+RvcFdGXWyoN9s80WdCHjOTdlRlKfltGagUA== 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 BL1PR12MB5079.namprd12.prod.outlook.com (2603:10b6:208:31a::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5525.11; Tue, 16 Aug 2022 04:43:10 +0000 Received: from BYAPR12MB3176.namprd12.prod.outlook.com ([fe80::eca6:a4a7:e2b2:27e7]) by BYAPR12MB3176.namprd12.prod.outlook.com ([fe80::eca6:a4a7:e2b2:27e7%5]) with mapi id 15.20.5504.027; Tue, 16 Aug 2022 04:43:10 +0000 References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220816022102.582865-1-haiyue.wang@intel.com> <20220816022102.582865-3-haiyue.wang@intel.com> User-agent: mu4e 1.6.9; emacs 27.1 From: Alistair Popple To: Haiyue Wang Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, david@redhat.com, linmiaohe@huawei.com, ying.huang@intel.com, songmuchun@bytedance.com, naoya.horiguchi@linux.dev, alex.sierra@amd.com, Felix Kuehling Subject: Re: [PATCH v6 2/2] mm: fix the handling Non-LRU pages returned by follow_page Date: Tue, 16 Aug 2022 14:42:38 +1000 In-reply-to: <20220816022102.582865-3-haiyue.wang@intel.com> Message-ID: <87ilmsvlwk.fsf@nvdebian.thelocal> Content-Type: text/plain X-ClientProxiedBy: BY3PR10CA0027.namprd10.prod.outlook.com (2603:10b6:a03:255::32) 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: 1a4201be-c3dc-419b-bb55-08da7f41d1ee X-MS-TrafficTypeDiagnostic: BL1PR12MB5079:EE_ 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:(13230016)(4636009)(366004)(39860400002)(346002)(376002)(396003)(136003)(9686003)(38100700002)(26005)(7416002)(5660300002)(6486002)(66476007)(6512007)(478600001)(6506007)(86362001)(8936002)(6666004)(41300700001)(83380400001)(8676002)(2906002)(4326008)(6916009)(66946007)(66556008)(316002)(186003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?tU5OlVhyUl6wm8TFEbtwqz3Uwj8EkezbY5Mc/hNeqijL02ji5EDcgNJMDYE0?= =?us-ascii?Q?bioQlIoUyWe592oeArgV5Aj54ArRVxo2JmrhVzszekCwploBEwEnp6KlwQOO?= =?us-ascii?Q?5TThbsGRmVXuIoPDm+ZQ7cVTUMVSNON19Wz/tFfUXQDXnV0qWtiw4pVYBTVm?= =?us-ascii?Q?3HaCK5Y1xTtFdtykIrHAVhMeiY3z3yPPS4LjpC4Vq4H1uufgQuGOBa1AQlgO?= =?us-ascii?Q?Y8PzWalGFGkry0iH/3H4xiCkm22bRgqjHjCeZ6eRoZfXc5g3ZUxUoh9crlCy?= =?us-ascii?Q?1I1q6UzGJmrgnRFFFowUuLwOZYKGzFJF26bzRyM0Wl9S/sMGaKsYQL2KAX6Z?= =?us-ascii?Q?uXe0eftSpKUYGrS3KKkyLQWlqVk+T8RTs2V13DUfSe5JH94hkTeKLgj4/Zs+?= =?us-ascii?Q?X8+pawrd5v/RGJcHJCWTRqdtAOqt5oI7wiWKslgGk6pT1bUy5NkQknvCfBCd?= =?us-ascii?Q?gCk1ke+xNPCNuz9UP3IoBdu4yqh6m+4TbRDdxhw6lqrSNNEPXWNBkbMeX71l?= =?us-ascii?Q?dMReXxVTSonB/HE3wrf9+m+Kju1dUZIw/oAYv736Br+SPz0SUaVRNOkk/p+L?= =?us-ascii?Q?YaEUSv85GoHfBuoCFW3kY8l8QF2aqHnwRfEiebz8dF5lilowmak2QSjvL/xj?= =?us-ascii?Q?aj1EdLZI3zYOVEpxDQrRbPwkTHsi89RAm8h1XZQSqlMC7YINZM/SaOHmNKRP?= =?us-ascii?Q?mnmdh2Hv6m2QgsNXkeG3zCIdtVJhwpCStAtPoK9Kz5UgkJTfhs0D5Hf7ytgt?= =?us-ascii?Q?ttaEr6KgOKs+BsZ4v23Gho53Vs+b25BXbZUhCgXBcX59qWjmsBX57t69H9AB?= =?us-ascii?Q?nYO6F+k9dt2rM8cj4vqaKJtONa0gyWiWDFD9J7t4hDWCzxd9vDwHKkre86Yo?= =?us-ascii?Q?Emq1fDoANVLQU2C4uEfkanEOMGYuokONWlqvCvO57RIUU6Rywnm6d4qtNXJh?= =?us-ascii?Q?C56bbFIVHYnZfywYJ7brWP8eoR6a9RZYMYCx9iz9UV2Q9adFiajCpmRJEQoT?= =?us-ascii?Q?ki07q3WiH2FCblGQL7clyAW6Os39qlkuYOIe7FebUi6KGWjej5lG1TH/CQFT?= =?us-ascii?Q?WMM8XbQjKzaUj8mcUDVaoAczFzvyyTUju2cR/NSTs591vrlh9dmhGkW/Ul6R?= =?us-ascii?Q?MuLjMKRNXvtW9Up2BbYk/AyY9S4zElH6uIqmTRX2JVI8pMQ0pp5jk1R9MHvf?= =?us-ascii?Q?6Mbpf1hsqFRmxDaKg3rLqIaH+AGzf4Umt/qUV4Dpga7WoTmYzozwfcuQIRyd?= =?us-ascii?Q?dMInGDGvWLo4q3Zy6OkqM393lRF6p5lBY8ybg5mYw/lxoYAhAIX9WNDP705K?= =?us-ascii?Q?FgnKHci3SwWfJoHoP18va0QG2uku9T1nchMQEP9GMzhNftXpYAFpkxV41pwX?= =?us-ascii?Q?sS6pXD+WFfBeUPo/puHVYJNRmH7JnpiM1qC2i7beg8pZaO7P17Jp25dgGbgb?= =?us-ascii?Q?RkWFGCtKUy6iS5xDECYDf7Xk7LN3JJeryalUy7oumYUQ8N2KRUqv3VwUcz6g?= =?us-ascii?Q?hWXIeaUcpus9MXOB2FSl/zHSX3OsyG4sInNeB0iAdGf22V2mv2BZUM3EfsgS?= =?us-ascii?Q?HrUPL7643z3mPLebSYVHft5y/MAJI4tofLlUhdxq?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1a4201be-c3dc-419b-bb55-08da7f41d1ee X-MS-Exchange-CrossTenant-AuthSource: BYAPR12MB3176.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Aug 2022 04:43:09.9750 (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: df+LBH4scSgL2bmkFvis9VNjZdddNmQ8Na+c+gUVxYKWjEy/aGz+WYWfzhHd+o6Ie+wTwiXVgiZvgE1oDIdICg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5079 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Looks good, thanks. Reviewed-by: Alistair Popple Haiyue Wang writes: > The handling Non-LRU pages returned by follow_page() jumps directly, it > doesn't call put_page() to handle the reference count, since 'FOLL_GET' > flag for follow_page() has get_page() called. Fix the zone device page > check by handling the page reference count correctly before returning. > > And as David reviewed, "device pages are never PageKsm pages". Drop this > zone device page check for break_ksm(). > > Fixes: 3218f8712d6b ("mm: handling Non-LRU pages returned by vm_normal_pages") > Signed-off-by: Haiyue Wang > Reviewed-by: "Huang, Ying" > Reviewed-by: Felix Kuehling > --- > mm/huge_memory.c | 4 ++-- > mm/ksm.c | 12 +++++++++--- > mm/migrate.c | 19 ++++++++++++------- > 3 files changed, 23 insertions(+), 12 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 8a7c1b344abe..b2ba17c3dcd7 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2963,10 +2963,10 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start, > /* FOLL_DUMP to ignore special (like zero) pages */ > page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); > > - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) > + if (IS_ERR_OR_NULL(page)) > continue; > > - if (!is_transparent_hugepage(page)) > + if (is_zone_device_page(page) || !is_transparent_hugepage(page)) > goto next; > > total++; > diff --git a/mm/ksm.c b/mm/ksm.c > index 42ab153335a2..e26f57fc1f0e 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -475,7 +475,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) > cond_resched(); > page = follow_page(vma, addr, > FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); > - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) > + if (IS_ERR_OR_NULL(page)) > break; > if (PageKsm(page)) > ret = handle_mm_fault(vma, addr, > @@ -560,12 +560,15 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item) > goto out; > > page = follow_page(vma, addr, FOLL_GET); > - if (IS_ERR_OR_NULL(page) || is_zone_device_page(page)) > + if (IS_ERR_OR_NULL(page)) > goto out; > + if (is_zone_device_page(page)) > + goto out_putpage; > if (PageAnon(page)) { > flush_anon_page(vma, page, addr); > flush_dcache_page(page); > } else { > +out_putpage: > put_page(page); > out: > page = NULL; > @@ -2308,11 +2311,13 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) > if (ksm_test_exit(mm)) > break; > *page = follow_page(vma, ksm_scan.address, FOLL_GET); > - if (IS_ERR_OR_NULL(*page) || is_zone_device_page(*page)) { > + if (IS_ERR_OR_NULL(*page)) { > ksm_scan.address += PAGE_SIZE; > cond_resched(); > continue; > } > + if (is_zone_device_page(*page)) > + goto next_page; > if (PageAnon(*page)) { > flush_anon_page(vma, *page, ksm_scan.address); > flush_dcache_page(*page); > @@ -2327,6 +2332,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) > mmap_read_unlock(mm); > return rmap_item; > } > +next_page: > put_page(*page); > ksm_scan.address += PAGE_SIZE; > cond_resched(); > diff --git a/mm/migrate.c b/mm/migrate.c > index 581dfaad9257..44e05ce41d49 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1672,9 +1672,12 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, > goto out; > > err = -ENOENT; > - if (!page || is_zone_device_page(page)) > + if (!page) > goto out; > > + if (is_zone_device_page(page)) > + goto out_putpage; > + > err = 0; > if (page_to_nid(page) == node) > goto out_putpage; > @@ -1868,13 +1871,15 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, > if (IS_ERR(page)) > goto set_status; > > - if (page && !is_zone_device_page(page)) { > + err = -ENOENT; > + if (!page) > + goto set_status; > + > + if (!is_zone_device_page(page)) > err = page_to_nid(page); > - if (foll_flags & FOLL_GET) > - put_page(page); > - } else { > - err = -ENOENT; > - } > + > + if (foll_flags & FOLL_GET) > + put_page(page); > set_status: > *status = err;