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=-9.6 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,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 B00E0C433EF for ; Wed, 8 Sep 2021 22:42:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 587626108B for ; Wed, 8 Sep 2021 22:42:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 587626108B Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id CE5E46B0071; Wed, 8 Sep 2021 18:42:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C93BB900002; Wed, 8 Sep 2021 18:42:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B5AB26B0073; Wed, 8 Sep 2021 18:42:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0253.hostedemail.com [216.40.44.253]) by kanga.kvack.org (Postfix) with ESMTP id 9D5CF6B0071 for ; Wed, 8 Sep 2021 18:42:31 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4A2E530177 for ; Wed, 8 Sep 2021 22:42:31 +0000 (UTC) X-FDA: 78565881702.31.3167F62 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2071.outbound.protection.outlook.com [40.107.236.71]) by imf12.hostedemail.com (Postfix) with ESMTP id B4384100009D for ; Wed, 8 Sep 2021 22:42:30 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=ZZGI5ggKP1yi15VKbpdtedkTTJlCSnKl0dx0GMv/wSKNc2RScm/E89e1Wm5uhd9tXS+4FAUpd/HWFVfW+HL8I6hUVUkF4zlgaqpwko3xl/CbVgCuBeZghJRNG/rwbDVjNtHrqYW42/CdGMZBZtdxlEhJhjONwxHsd9o5gSE35uK2qJSMzfYMzKLDK48dPt7Thzhtqh9O5C3dJ0YS+yqGbbzhF407IKhIDKFHm/cjz/tQS/+Y7J2FLUR1KVsxxhTpJNvzeKIFmW+uQ/TTO0izujr2uhQ4aXAHzDLu9z7+3q1+U0VeMYvrdNbKqev+sNthffGYsgTf6XQgT8C887IJNw== 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; bh=ghGDySCOxD+tyRl9gZZ86W8oVwsc0UKlgQlzTddFF/4=; b=SaXLXgJX24JyOFxGeZjU9wZjCyYQ79w4N4U0P/ZUaUnGw6/iiYfMM6u+oIT6q1QInXtJ5qkXq5erEuRXaonvpGKhQ4EvPYetyiMAL/ccxry+AS0Gdp1OWs02V45BdJP3FSh9RmmJsvLbvgn6r1c8Tr2rsHWq13yG4FbScnKHHva4Mw1wepTofgR85hDPUpsiFxmDoJVv0nZRutMIxGm0cNB7dVPETD/8LupFLZSyfmgQMGHi67uKA7AhGVCWIef3Ei2Dr7mkx3kATCtOmqirTjOAMZOfGiigs6mKMCE3AYdxp7SmK9wpMEhZlGRNRpOhwgge7sGMLEgAcGcj5go0yg== 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=ghGDySCOxD+tyRl9gZZ86W8oVwsc0UKlgQlzTddFF/4=; b=lJ9lZaOn9x4rHo0PKixEANSF9dajewvgIZRkKpCvxwwmBso9XkOD4PgnrRA00iEm9uB20fe2tKAKMJ8VWD6jUvpHGJspdgkMxjGR3MNlOcAF6vGGkXKSpPP6LRACOZkgJla9c69zZCUOQcAlnBRDzVO0SVsMrsJ+ds5k1yj0yCaxXybOSrKiDdfL18F71aFrkI0ptdErmM8bWb3hUtWQJnihtGVqBkaFgjJ5uE/5iUtq1Ng0rlsX16A4FhHi6EXmrHQEj0GDyf+wMo2csr7PNXLDtbHq17qBxCBJeA4PMQ4LTJgjmC4urSnOIKcAC1ej/cse50v98Wb4GyLfdMV9Fw== Received: from BY5PR12MB4130.namprd12.prod.outlook.com (2603:10b6:a03:20b::16) by BYAPR12MB3064.namprd12.prod.outlook.com (2603:10b6:a03:da::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4500.14; Wed, 8 Sep 2021 22:42:28 +0000 Received: from BY5PR12MB4130.namprd12.prod.outlook.com ([fe80::6811:59ee:b39f:97b9]) by BY5PR12MB4130.namprd12.prod.outlook.com ([fe80::6811:59ee:b39f:97b9%7]) with mapi id 15.20.4500.016; Wed, 8 Sep 2021 22:42:28 +0000 Subject: Re: [PATCH] mm/page_isolation: don't putback unisolated page To: David Hildenbrand , Vlastimil Babka , Miaohe Lin , akpm@linux-foundation.org Cc: iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210904091839.20270-1-linmiaohe@huawei.com> <3b36529f-ab97-ddfe-0407-66f0cd1fd38d@redhat.com> <2d06db75-5c26-8fe2-6883-ac99056a9894@redhat.com> <80cfffdc-227e-c045-be74-1c08fb62c1e3@redhat.com> From: John Hubbard Message-ID: Date: Wed, 8 Sep 2021 15:42:27 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <80cfffdc-227e-c045-be74-1c08fb62c1e3@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BYAPR02CA0031.namprd02.prod.outlook.com (2603:10b6:a02:ee::44) To BY5PR12MB4130.namprd12.prod.outlook.com (2603:10b6:a03:20b::16) MIME-Version: 1.0 Received: from [10.2.63.205] (216.228.112.22) by BYAPR02CA0031.namprd02.prod.outlook.com (2603:10b6:a02:ee::44) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4500.14 via Frontend Transport; Wed, 8 Sep 2021 22:42:28 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 8c54ebc7-36ef-4e27-e088-08d97319efc9 X-MS-TrafficTypeDiagnostic: BYAPR12MB3064: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:2887; 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:BY5PR12MB4130.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(376002)(346002)(39860400002)(366004)(136003)(396003)(83380400001)(4326008)(38100700002)(31696002)(6486002)(31686004)(2906002)(478600001)(86362001)(4744005)(16576012)(966005)(66556008)(8936002)(8676002)(66476007)(66946007)(316002)(5660300002)(36756003)(2616005)(53546011)(26005)(186003)(956004)(110136005)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZFkvbGJLZ2RXVmdZQ2Q5VWlVNEdiK2sxYjlRczBHbVJNcVdjVlF5MnFXa1RS?= =?utf-8?B?Z0x4R1VxVFFOQ1VENEExWnNSYTNtUitoY05LOUY3ajBVR3c4Z3h0ZEtQdTRo?= =?utf-8?B?SXdPZUxSMktnNmozMjVQUHEzN0lCbzlqdzBOSVI3UHZ1VHJNNWE2eVY3RHdj?= =?utf-8?B?bmoyWWxHOW84WTg3TFBJUWNZdDE2aXV0aVlTYjBGdXRGWXAwZW5tRXA2NDRt?= =?utf-8?B?VytjSDlROGI2clBOU0VnbUtIM0JkbFdnVXE4YVpaMmllZ0U4R1JMaGYwMkVs?= =?utf-8?B?b3MwM1F5TVlKV3dycGZuOEl6c0hGQlU3V2l0UWx4N2ljVDc4ckpmODhobTlh?= =?utf-8?B?ZEptRUZnSEtaMjhKSzhCWlRsdEJXUnkzV0dXNG1tTzJrK2g4UnNGR3NYSlhZ?= =?utf-8?B?R2hxR1ZJMS9aMlVLak9Uci9HckIvZXFYK1E2YWhRU045V0VzdURNRmRrcWl0?= =?utf-8?B?d09zUWVDWGFLL3haVlhtQzZxZksvTUZrYVRnVTlwL3p0bnBURlljMUEzYXFi?= =?utf-8?B?dGMwZ05LQ3I3M0RiUDVBVWIxVW8wQ09TUG1lVk1OK2xzT2pZL2RheUpMMmdT?= =?utf-8?B?cWQ4ZGdaM3k3OERXUXFsaEpHUVdtbjhOZ0VZMnR0bnJHRmg5UGJkemM0YkFt?= =?utf-8?B?ejJmQmZMY1A1RkFpYllWR09kTWZDNG5oS0RJeloybFdBY0ZYd0NEcFFQd3JO?= =?utf-8?B?WFZBM1FDVCttTTlHa3pYTkptdUVmZ2lFakMrK1o4M1dVY1V5djdGUjJDb1Nq?= =?utf-8?B?K0JRWTBZUE5sVE1MaVIvR2Q2ZFJXbThLVkY1QTZSSUNwVHVxSEl5cFJMeCtQ?= =?utf-8?B?UVFKUzNlZ25oRDRacnNHTUlLYmo3MnFQdXppcDBKQVdIeXhzNTBTbldYUTcz?= =?utf-8?B?ZXBicCtEUFZVWFJTMTdtekRNS0pyOEx0Y0EraE1GcjBRSkJjU3NGV1dJeHBR?= =?utf-8?B?V1VnQWo5RXN2SmM5KzBVWmY3aURCd0ZobHBmVVBDdUNGakNnRGNmRzZBWU5E?= =?utf-8?B?UUZ6S0IrMXB6ekFuV2xveUxlZ0JYYVdRd2RhemhKcDkwOFhLL1pDVGNmSkNk?= =?utf-8?B?eHNYT1ZtTTR0VjVCMXJ2QXVSaDlPMDh5elNwTHc3dUs4bUNHMHJyUGc3MnEw?= =?utf-8?B?NWJkTlZCOEQxUmdCdHJsSXFQM3FzNlNXNXdES3JjN2FMc2tYNmltUjY4RUtM?= =?utf-8?B?M0hjaDl3WE1Oam13ZnpuMXBqcGIrTm5OYVJSY0RPMGlGSGlNYmwwc29NeXkw?= =?utf-8?B?RG1oSW05QjlXQnoyeUNHMWJKcm1tdG1WTUNiOVZvbTdnbDZsaXpMb01BeVNI?= =?utf-8?B?bGxHSnZ5eVVnWm9DN2lwWUJkcy92QnBRNUJEQXppNUxiK2xNZFM5eDU5VjN5?= =?utf-8?B?a2IrNkFwM3JIVVBHRkc0WHVvQWxpcm1lc3VUNHRPeHRyUlE0SmdXbGtWVHVq?= =?utf-8?B?ZDJQelJ2QzliRDlBMTVOL0VPWWp3SkVmKzFJWlRCVkJERHh1Nyt6SHp0ZWFh?= =?utf-8?B?NDB0OFNlTVlhUmJWVkxVTmkxS1RuZXZyZ1d6MzZ2WEdiU25YeHgrL2hlU1pU?= =?utf-8?B?U1JXeS9KSktpSnFkUFU0dEVzODZGZS9RSTVzRlBEM1gxVnNFWEV0NGloN013?= =?utf-8?B?U3pDUlN1MkdRWVVkb29RaVdjd2w5NXFmbExiL2JWMTQvNndXRHBuU1V6QTFD?= =?utf-8?B?UUhJRjNXWXM0VWN6Zi84THpZM1hQRFZhayt5enVHN000WXltamtIdG11Ry90?= =?utf-8?Q?xJF33NzWBZRwGADoW0lDcF4fRfEVuj5UuRGg6SF?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8c54ebc7-36ef-4e27-e088-08d97319efc9 X-MS-Exchange-CrossTenant-AuthSource: BY5PR12MB4130.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Sep 2021 22:42:28.7213 (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: pDaUNOVL8ANp2atITFkJ+3fE/PCWqhChzk4iTk5lG8GtH4l+Adb77bK6+EKztQ+C7VoLyOMU/0gu2wFwxrKtXA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR12MB3064 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: B4384100009D Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=lJ9lZaOn; dmarc=pass (policy=quarantine) header.from=nvidia.com; spf=none (imf12.hostedemail.com: domain of jhubbard@nvidia.com has no SPF policy when checking 40.107.236.71) smtp.mailfrom=jhubbard@nvidia.com X-Stat-Signature: giuju55ako6crn39grmiq3ewxyqtz4x4 X-HE-Tag: 1631140950-144279 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 9/7/21 2:56 AM, David Hildenbrand wrote: ... >> If this can be handled gracefully, then I'd rather go with VM_WARN_ON. >> Maybe even WARN_ON_ONCE? >> > > I think either VM_BUG_ON() or VM_WARN_ON() -- compiling the runtime checks out -- should be good > enough. > > I'd just go with VM_BUG_ON(), because anybody messing with __isolate_free_page() should clearly spot > that we expect the current handling. But no strong opinion. > If in doubt, WARN*() should be preferred over BUG*(). There's a pretty long history of "don't kill the machine unless you have to" emails about this, let me dig up one...OK, maybe not the best example, but the tip of the iceberg: http://lkml.iu.edu/hypermail/linux/kernel/1610.0/00878.html thanks, -- John Hubbard NVIDIA