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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 65AD1C433DB for ; Fri, 12 Mar 2021 20:13:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D149664F72 for ; Fri, 12 Mar 2021 20:13:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D149664F72 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 627026B0074; Fri, 12 Mar 2021 15:13:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5FDDA6B0075; Fri, 12 Mar 2021 15:13:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 44FC86B0078; Fri, 12 Mar 2021 15:13:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id 298C16B0074 for ; Fri, 12 Mar 2021 15:13:51 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B5A1C6C37 for ; Fri, 12 Mar 2021 20:13:50 +0000 (UTC) X-FDA: 77912323020.19.F78AA70 Received: from aserp2130.oracle.com (aserp2130.oracle.com [141.146.126.79]) by imf17.hostedemail.com (Postfix) with ESMTP id 1FB25405EFC5 for ; Fri, 12 Mar 2021 20:13:39 +0000 (UTC) Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 12CK9dii147529; Fri, 12 Mar 2021 20:13:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : in-reply-to : content-type : content-transfer-encoding : mime-version; s=corp-2020-01-29; bh=T/IbeDzam8FFEPAoPCyV87WKBGLeyZHJlwXV+iD7Gso=; b=WNhn9GsxJ9qxs6Uib9vcqoOQh5MdXWxKmOboO+1GOwCZJwh7/8gAvcVT8p4T0lETlV0B JHijWX3wV5NxpdjQUU0IIiBYejxAcRVFWlAoP6BfuAnMV69TNeflwqGLr79we9epaUPG QCKVAP2HztBJbkzA1jle+ZQE3a1se9iTZrxvBi3HJ6aMXl0EOaK8c+c0HJOXzTiPC58e DiHrlGlpV89dCf59Q2oMYUtr8fzDHIGCXCAGQY9PWZuoDVrN2BxOcp1bFDpDuoYZjLCJ JfLDjhKJSvn/hnE2poTYIbPHQUokm1xHsFWm6QbiVuQar24+9bm0X8tCSw3+sKTrVDCw hQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2130.oracle.com with ESMTP id 373y8c36f3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 12 Mar 2021 20:13:35 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 12CKCxCm054572; Fri, 12 Mar 2021 20:13:34 GMT Received: from nam02-dm3-obe.outbound.protection.outlook.com (mail-dm3nam07lp2040.outbound.protection.outlook.com [104.47.56.40]) by userp3030.oracle.com with ESMTP id 378f52r137-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 12 Mar 2021 20:13:34 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=C8+CLZbSKz9tbE2VavP90fL2MLL3LQyqId7sJrub0YDhY5Whb6DftLst5pPXmMl0tajNYTtQUA81wobQAqozTVXVrOw9lxXb+vCoRrzwc2hkzSYLqv7lH2eBn7aJLVXjTQs4Vxgh1mD/ZxV2FFACVN4yosJ6eHE36ssGOLLmdrRTLBLAl2LxQMDgb4o7yFrnJVRkyO84knRwBzcMrkJuQxrdKQ2l2QWeWw+XcC+c6uS2bFoWTdoxDeBcNPlwg2bk1iuLKcdWqujIJmXzMeX/0XwsYv/gBMjBvXLmEl+QSQ5cVXOof4CVE3hOPmwksxQF6+wj21MeqG23xYJLMMqsiw== 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=T/IbeDzam8FFEPAoPCyV87WKBGLeyZHJlwXV+iD7Gso=; b=Sy/EadQexwWNWZlw0xKRI/kupTuDzypUr0JYAK+RDoav16AagEeKzlEIp+8KbudAwmfXwxRauZpUBERc4fB8FVF7Capelq3jJe2EHmS8kWWQS9QAIndI4dDtTStySoXeu5iQFSLBGD8YK+g7Mv4bsk0vu030iTTH+bBSll3KVe/8J5EgjbVxx9hgLHxCpvEBoegWZm2z2lG85L+Aetp8glnyfK73hE9t7mRoLEZ+oNcAeiCGKggByN3J/O7Fr3o5rR6Hep/wHqjWZKJfkj4by9HQxdsn1Kc7AVjPl9WNJDKUfsAT0De6a0PP2CAvh4VrpxFv6UylhFlxTYQ+Fp1U2w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=T/IbeDzam8FFEPAoPCyV87WKBGLeyZHJlwXV+iD7Gso=; b=DRrXjvbK23loK80x5VAS5MOLX1swZKDYqc1Sf081EfZ46Nqj/JYkMxAk4OVqcHB2upyP+iWyWSkYzkWeZQmJIbX6sQyINE/JeJ3x5UvK/OM9fc7ozmtsXy2i39JTnQ0hoScaAi6HhpkxBc6ADodPMXW034js8nThkhIL94GZkn4= Authentication-Results: kvack.org; dkim=none (message not signed) header.d=none;kvack.org; dmarc=none action=none header.from=oracle.com; Received: from BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) by BYAPR10MB3157.namprd10.prod.outlook.com (2603:10b6:a03:14f::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.17; Fri, 12 Mar 2021 19:58:14 +0000 Received: from BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::980e:61ba:57d2:47ee]) by BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::980e:61ba:57d2:47ee%8]) with mapi id 15.20.3933.031; Fri, 12 Mar 2021 19:58:14 +0000 Subject: Re: [PATCH 4/5] mm/hugetlb: simplify the code when alloc_huge_page() failed in hugetlb_no_page() To: Miaohe Lin , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20210308112809.26107-1-linmiaohe@huawei.com> <20210308112809.26107-5-linmiaohe@huawei.com> From: Mike Kravetz Message-ID: <987f50e0-5511-7f53-c4b9-d8878d840bb5@oracle.com> Date: Fri, 12 Mar 2021 11:58:12 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 In-Reply-To: <20210308112809.26107-5-linmiaohe@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [50.38.35.18] X-ClientProxiedBy: MWHPR1201CA0001.namprd12.prod.outlook.com (2603:10b6:301:4a::11) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.2.112] (50.38.35.18) by MWHPR1201CA0001.namprd12.prod.outlook.com (2603:10b6:301:4a::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.17 via Frontend Transport; Fri, 12 Mar 2021 19:58:13 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 9a660517-2b3b-40ee-c030-08d8e5912bc0 X-MS-TrafficTypeDiagnostic: BYAPR10MB3157: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:1201; 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:BY5PR10MB4196.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(136003)(346002)(396003)(366004)(39860400002)(376002)(8936002)(5660300002)(2616005)(66946007)(956004)(66476007)(83380400001)(2906002)(31686004)(66556008)(16526019)(36756003)(4326008)(316002)(16576012)(186003)(26005)(53546011)(6486002)(478600001)(52116002)(31696002)(44832011)(86362001)(8676002)(14583001)(43740500002)(45980500001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?eDMxc0ZmL2lmanB2dW0ybGZNUExGTmlERDdCTHBmM1VITnNPMUdWYjg3S0lr?= =?utf-8?B?VGdRMlY0cm9zb0RpeTI1dFBFZyticTdNOENweFVvLy9DMjBBWFNPeTRMZWFu?= =?utf-8?B?RFlSa252R0NDVXl4T0diS1pvZjVxRDZzQUdpS1B2Z2pYUHpVeXFJMnVnQUZ2?= =?utf-8?B?UWV2N0dGVldEM0N0V0I5SDJ2Q2FHZzhxSWpZZ2dsNC9VNHI3T2VZSGF1YjRS?= =?utf-8?B?ZktWejROY3JtYzRXa25vWU9Lb1Q2UWIxNWttQ0tVeXNDQkhiMlNVblorK2lT?= =?utf-8?B?eksrNUt3eHYxUjhVUkY3K1p6TG01YmxQTmQ1Tm5hTHBYUzJUUXNDMm1iSzZV?= =?utf-8?B?QXZ6MHpScWVFLy80bWpvTFB4N3ZWZkgzSlk5bGNYWndTZGY2dHNkT0c5MFdq?= =?utf-8?B?UXZzV3Ryb3NxRXpIOExOZVFFVHpJdjB3YVJLaU9KT3oxbXBOc2hiUlVEUGdz?= =?utf-8?B?QlIraUVEcWcxU2VUSytiMXVZMmNJMW9DMW91b2R4aHE0eVhKNTI2MHFwQ3VS?= =?utf-8?B?c3FwekFRUDNITzdMMGkyd0tqcm9WQVo5cWxBUFFKU3BjMndzYWZZdmN2K2po?= =?utf-8?B?VEt4dUk3ZWlHaFc3d1lxTjlLT21jWWxYSzRaZXh1b2hUdFovUTRpbnpzcXlC?= =?utf-8?B?WVlIZTZoOG1aVVYrRTRFSC9vTHFGd1kyakNjT2JlUWowQnBObXZCMUdDeE9J?= =?utf-8?B?SWJ0NkhZUW1DQTlseWtxUDBrTVBFSWxOa0hyU2RUdkJlMlBmUGNHcjJleHQw?= =?utf-8?B?M3k0cEJlemRWNWpIanBGZ0xMVFd4WVo0cUFacHM0Sk5OaTU3bzYwQUhML0Rm?= =?utf-8?B?M0NTYk84QUIyMkY1QnNaM2lwRHZGNTBEVHFaRmFobzNud0s2U3ZabFkzOVBH?= =?utf-8?B?eTd5dFBLNnV1V3ZKVVVZcFBmWVAwZEVxV25oSWpKUEZ1d1Y2TmEwYys3QS9j?= =?utf-8?B?bVh3UkVMaW5OTVB0VHhKWUJiT0UrT1N2ODVrMkEwMitDTGJJTzJ0Uis2WEhv?= =?utf-8?B?WHdwRm5NdExTUTVwbzJNL2tPdjY2S0VOK2FZYUFWU3ZaUTNTSWRqak5KL2RE?= =?utf-8?B?WS9RaGQwL0hYcGNrNDZ3QUpGcUh1WVlrcEQrVDkyRFE0QmFyN3B4OTVXL2hh?= =?utf-8?B?bUdWK3VlYjNsZ2Fuc1NQb3dIL3BsNEhQOW1hYTRnWm1hdVhNbmE5WkwreTNw?= =?utf-8?B?eVUvTWU0SXdJYXAxYnZ2ZG1SdGd3OE9YTWcrYkx5bTBVTnk1eGdENWVjSFFH?= =?utf-8?B?VnZCTjFCSlRHeisvbWxpVHRnUmk3Um5XV2dSRHc3TGNWTkNtOUhVUXBxZDV3?= =?utf-8?B?UkJ2emI4ZkQ5SU5jc3ZZYWl4SCt6VnpvRFJhTnYvamdEWlpqUzliMmNBOHVk?= =?utf-8?B?MGxBSnNybWV3aTlxQ01yU0FvUDhDNktTeWNSYVhYUHpNRHNJYm92dHRVRGZ1?= =?utf-8?B?eW4wRnBRQjZNb05QbmlzVGVYSkFUVENVUFFtUzk0a0NBb2NaQ2Jkbm11c0Yx?= =?utf-8?B?QW1HbkFKOERqU3ZWbjFkbGZvMitJSVFYZ2ppeHFXcGl0MERSZXpBRHpuWWhT?= =?utf-8?B?QmtyeHlDS0lydUFvZkRESmJjLzE3YWVPYi80bXdENHBmY3g5OGhmTDI5bkxW?= =?utf-8?B?eDByRndYUFV6UmtIYkRLQ0ltbVA4azkyL29zc1dvTkF6THFxY0NqSUo1MUpz?= =?utf-8?B?Sld4dXliYThISHFENGNNRDc0M1JIY2VnTHNUUlRPWDYyQ1N4WjYvY09TMGdF?= =?utf-8?Q?91zUEtqhr9wG7N/5+2iZBKZx4FZ9rEwHdvXWM6W?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 9a660517-2b3b-40ee-c030-08d8e5912bc0 X-MS-Exchange-CrossTenant-AuthSource: BY5PR10MB4196.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Mar 2021 19:58:14.1061 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: HSEeuZNwYjtVbgAwq2mwnDZX6tYS4u+zQstGG6HS3s1UojmQc5kIZFuvqL2mUXdPGR3lnf2h5+SlqcMznO3wcw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR10MB3157 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9921 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 suspectscore=0 malwarescore=0 mlxlogscore=999 mlxscore=0 adultscore=0 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103120147 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9921 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 clxscore=1015 mlxscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 adultscore=0 mlxlogscore=999 spamscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103120147 X-Stat-Signature: du5cknxknqek5brw8nqatdbzy8rfiz6e X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1FB25405EFC5 Received-SPF: none (oracle.com>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=aserp2130.oracle.com; client-ip=141.146.126.79 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615580019-603238 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 3/8/21 3:28 AM, Miaohe Lin wrote: > Rework the error handling code when alloc_huge_page() failed to remove some > duplicated code and simplify the code slightly. > > Signed-off-by: Miaohe Lin > --- > mm/hugetlb.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 695603071f2c..69b8de866a24 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4337,13 +4337,10 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, > * sure there really is no pte entry. > */ > ptl = huge_pte_lock(h, mm, ptep); > - if (!huge_pte_none(huge_ptep_get(ptep))) { > - ret = 0; > - spin_unlock(ptl); > - goto out; > - } > + ret = 0; > + if (huge_pte_none(huge_ptep_get(ptep))) > + ret = vmf_error(PTR_ERR(page)); This new code is simpler. The !huge_pte_none() catches an unlikely race. IMO, the existing code made that very clear. Would have been even more clear with an unlikely modifier. In any case, the lengthy comment above this code makes it clear why the check is there. Code changes are fine. Reviewed-by: Mike Kravetz -- Mike Kravetz > spin_unlock(ptl); > - ret = vmf_error(PTR_ERR(page)); > goto out; > } > clear_huge_page(page, address, pages_per_huge_page(h)); >