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 96D75C433FE for ; Wed, 18 May 2022 22:36:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BB4CF6B0074; Wed, 18 May 2022 18:36:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B3C096B0075; Wed, 18 May 2022 18:36:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 91D178D0001; Wed, 18 May 2022 18:36:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 7FE126B0074 for ; Wed, 18 May 2022 18:36:37 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 50FBB20AD9 for ; Wed, 18 May 2022 22:36:37 +0000 (UTC) X-FDA: 79480324434.15.7D2D883 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf25.hostedemail.com (Postfix) with ESMTP id 17215A009E for ; Wed, 18 May 2022 22:36:12 +0000 (UTC) Received: from pps.filterd (m0246630.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24IMIqOH007853; Wed, 18 May 2022 22:36:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=message-id : date : to : cc : from : subject : content-type : content-transfer-encoding : mime-version; s=corp-2021-07-09; bh=cnH6W7b6tE1y/CQthqwY7SYjsLdrzQWrzsUeQvb1sLY=; b=1G78fsCkXtobwcEoIcGRPJ4egfZ4pOxaMIZd/urwanGEBJ3p6O+Zsn9nbmtntXXK9Cdt xRuaH9D2y2KFm9EkDluP8KVlYpsladDfbXkV5gusZYz5yasEvJTodxbE3rTuFoIK59c6 lJv1GyiljmdbtxQWhvQ9S+wpknrKox0RoACmErkwACAkXSoHGb/bBlu+2vE1l2shcqyz pdlExj0VrKn7Meu8hcSWjYLJMTh7F4DlUejEzY4NiuR/N1vesgpQFeeafBDisUq0+Hqc wQIWyLzHqZnL2jK629Ms5bYbNxF0lFn37YHgGLJ0/u4abPXk+TfU6SI5/UibG+b01Siy hw== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3g22ucadsf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 May 2022 22:36:34 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.16.1.2/8.16.1.2) with SMTP id 24IMU1kY013286; Wed, 18 May 2022 22:36:33 GMT Received: from nam02-bn1-obe.outbound.protection.outlook.com (mail-bn1nam07lp2045.outbound.protection.outlook.com [104.47.51.45]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com with ESMTP id 3g22va7usd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 18 May 2022 22:36:33 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Dr0iEOVvL8EqIkXs2HVrhQLYvFvf4usBSOsy7MWlhVg65gkjXrxSrq8VYUDvy6mp74z/q9ob3chku9YCgc6w6OKIXra4rqySYS5gQbE3O0KgHgR5fOEnYJZkQBN/42yTADRyeqFvVG05elPCSC8NnNT6ufT7Bkpdfxck2A2Iqo8zKDIs9wML0DhPfYsYMlwJK8o7nRovyf7wYQL6IlL3lddCAVzt1dR9vTHd9EGAaly9s5diYHpayENEXcsyuxGARovs3sDuPDFRy3tY8/eQ7/IofGXA3vRIbgsKp1X2r7dKXLe2irLaKx6EubJtrrju4SsD+KKMBo5nplT03zj2/w== 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=cnH6W7b6tE1y/CQthqwY7SYjsLdrzQWrzsUeQvb1sLY=; b=UFm/nqeqzDvF7A41e9BqA9qFD/b26NwBAB8UebU1q1WbmN/HCpQRAiN20NtDWRtjiWASF+g6FxVpR0pBAU/pA1fKXXgTjhpLlee8nAslvjVSgRvGhX2TXSDVqRZIMbxooU3Z6VUmiNpb7I78OL3/OoduyTVDYrIm+89/SAbDWiUu4amGPGA6T7HTIy1SHG7nY9EubmLkK6hBBEZl9hcOZgbpEfQj8bMx4nhWjJm61hpZ2/goTVcKP6Ja4MsVHAA1Rh04F5c12BEn++cs7qLvj5mFJUxyuuhiT8S5snUxy4PshuFEEzJlmZ2AiZH2W02KukpOkS8KgTGRfm3/iYfUUw== 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=cnH6W7b6tE1y/CQthqwY7SYjsLdrzQWrzsUeQvb1sLY=; b=YcV5lKu6IfqDfbRgxS5TSICL6Fm19+Gz3GwGPkimHuvhvs5u/roWrZrko6YOzfGAfPyJaB6ULXIr11EkyEt0/M//H5wiKTHcsXItrx8RggUY+hSSEubE9YKkM9/aLTjD1lvQKGsGngXxwfwk8W62rKjIKURtlcEh2OJrjpcUo6I= Received: from BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) by MWHPR10MB1823.namprd10.prod.outlook.com (2603:10b6:300:110::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5250.14; Wed, 18 May 2022 22:36:31 +0000 Received: from BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::2125:9bb7:bfeb:81f9]) by BY5PR10MB4196.namprd10.prod.outlook.com ([fe80::2125:9bb7:bfeb:81f9%9]) with mapi id 15.20.5273.014; Wed, 18 May 2022 22:36:31 +0000 Message-ID: Date: Wed, 18 May 2022 15:36:30 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Content-Language: en-US To: "linux-mm@kvack.org" , linux-kernel Cc: Michal Hocko , Oscar Salvador , David Hildenbrand , Naoya Horiguchi , Hugh Dickins , Peter Xu From: Mike Kravetz Subject: vma_needs_copy always true for VM_HUGETLB ? Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR04CA0119.namprd04.prod.outlook.com (2603:10b6:303:83::34) To BY5PR10MB4196.namprd10.prod.outlook.com (2603:10b6:a03:20d::23) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: f9aa33d4-c252-4c5c-1b45-08da391edb27 X-MS-TrafficTypeDiagnostic: MWHPR10MB1823: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:BY5PR10MB4196.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(366004)(6486002)(36756003)(6512007)(2616005)(316002)(31686004)(52116002)(6506007)(4744005)(86362001)(508600001)(8936002)(8676002)(66476007)(26005)(83380400001)(31696002)(4326008)(66946007)(186003)(66556008)(110136005)(54906003)(2906002)(44832011)(38100700002)(5660300002)(38350700002)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WGVhRkJtbm94WlVPbzhoYVV2RXg3NXUrTmZwYTg3TmlhbkdtOTNiZ3lPVFNL?= =?utf-8?B?dTJpMFE3RVlTbjljcTF0cHRaeVMvbW0xTjBuUEtlM2dmLzNGUGRrNUEzV0x2?= =?utf-8?B?TGdjZXYzbVlSTUJHT1ZLUTVHUHZ4R1l1djRpMjhwbEZpM2FCSysxR0ZTQ0or?= =?utf-8?B?MzA0U0lUeUc4NXorSDdBbTM5eTF2UzRsNGFZdlp3MXo0UnRBeUxlSTltRUNZ?= =?utf-8?B?TUhEOGtxa0Iwd1l6L00yRzhOQ0kxUXEvbnNQOGFOVDIwNVdOOGRWY1VKYmxP?= =?utf-8?B?OHFub09iRUdRMURFeDRPdjcwdUxvWDBYTS91alZOcDdobTVOdGtVVmlVRDdU?= =?utf-8?B?L3BhR0p2YkFDQTIrMjRncXJoazVWN0ZFK3ZIMVVONktUNE5rU1dTYjVuWXZi?= =?utf-8?B?eUZOQWVpSEE3Z1JNOS9aUmIzOHhSSWx2MTNDVHl3SnQxN0VqQXNHSWZnVEFI?= =?utf-8?B?K0Z4KytlNC9CMjRPRlVhU2F2UVFKTUU0blhaZEhZaWNPc0l1TjlqU291L01q?= =?utf-8?B?OFhselhqc3RlM0dld3lacGtDMW13QXNzWjR2QjliVm9JVVNwSXBlbVBKWVlZ?= =?utf-8?B?QnNXdVJLV0wvSWNZN01TaEs4MXcvWWM3VnYwK3czcUFlODRMKzBUcHROZWhz?= =?utf-8?B?eEQ2Unh5Zi9KcTBqVE9mRlVMTFp1bjQzQlhGV2g4UXNjU2JxTjhiMkw2dXZZ?= =?utf-8?B?ZERGMWxiTE54dk5WSFo2ajNpTG5XVGpXd1BhWk1RellmK1VVNFhSdEVMK0Mw?= =?utf-8?B?YjljQ1A0MmVDTElrc0dIV1lOU0lYdk0vdmNvcmZQRVQzNlN2SHd4N2UvbjFV?= =?utf-8?B?dExnV1Y4bFlDVFYxV1FHMFlHajgveEFqak00YlpjSXNqOE5Mdlh4VlJiWGRx?= =?utf-8?B?QlpaMXUrYlU4cWd5NEhxeG0rOG54Z3F0eUdGUUFnTFY3Uy9CRVBXb2sreGFj?= =?utf-8?B?eHpSOEMxUUxzU3ZoVkhxajlWRTZkWjBuQ0NpTmxDbkFrTkhLWEk2UXczNG1t?= =?utf-8?B?VGlhQTlZSGhkSVA5K3k0cXBSVGxhQ3ZjRVVnWmkwMkhJQkdKTXE3ZTZLeTRt?= =?utf-8?B?a3I3bE5ONXFZcGxSTVR2OHZmZW02alVBUy9BNFNaMitBbEtXbGNLblFqV2R0?= =?utf-8?B?MG54RVhreUNQdDhKaURuY1lDYW1Namh3a21TUVhxK2psOE9hZVNlaW9wZnl0?= =?utf-8?B?N2pTb3dGcXBaM1NMV2ZYL09UbFA3WVgrS3dKeVlLY3ZPSkw1WlpFNmxrc2FB?= =?utf-8?B?Z1R6S253dTFGRC9oNkpHeWlvK3Y1bWI5SitpeHBsVFpiQ3BHYUI1TC8yREx1?= =?utf-8?B?c2hUTk5hVXBGWldnZjQvTS94a1hjRCt5TjJvZVJUWFZDQzJQd2J2WVBKaXBM?= =?utf-8?B?dmJ1WW9rYmN3QUU1TVJpNVdYNG5xZm9DU1kvRkwrM0R6QkFTc2QxeDFvV1lF?= =?utf-8?B?NUZtOTlYM1pIMEgyZEh0UkFhc0RTYU40Y1ZHeC9FdEZwVzZUM21wR2s4OUE3?= =?utf-8?B?QkUrME55RUlHL25pT25JbjdDQlFrM3crSGpnMVFEcVV4ZWp0TzdidytDSG43?= =?utf-8?B?WHhmUjNxZWFXTHBtUlN2empGeVVGUUhxcjhjRVl4bC9nVllYM2R1M015K1dZ?= =?utf-8?B?YnZZTGVxS3NZNys4dXZnRlpqTVVCRnlDL1JUTjNzMURXNGNZbTIzUHVLVWI2?= =?utf-8?B?bzI0VnNzUUhEZjhmZVduNkNSTGJEejFrMkZFRENrcTM2d2Y0RHhlMkZkbWQy?= =?utf-8?B?VXpaSVFacTRJMWQ5Q0YvbTNQcEg4NHQ4RmN0dUF5MXE5QnBEK1R2T0t5WWVu?= =?utf-8?B?UzgrVTY3SmwwcGE0UG1BbWxnZFVYKzNFTzFtKzNvZ2haV050R3ppZ21VcWc0?= =?utf-8?B?NUZBcGRZb3l4RmNaOVMyeXgvb1lLbExqTlEwZnBRTEdtMDFUWDhQWlh5TnJp?= =?utf-8?B?UCtTUnVrL1dEWmJ4dkFDdXJsL3pDZHhYVk1vaUZOZlBZVkc3dWNBVS8zMEFo?= =?utf-8?B?dUVCTUFjNGNJWlFrS0NHalFpQ2ZFdzlyM3p4R2xnczZlVXpkdlZPMGlIYy92?= =?utf-8?B?Yi9DeGN5ajcxUjZBQjZXMTV6bVQvdUF1WUZKajdqdlZzOXBzNndHcWhmV3R2?= =?utf-8?B?TXdoS3RCQ1dHZlBFUGVIOFZtdnhvaEFOT1hqQWlrTm5CUlZKbWVrZFc5RGZE?= =?utf-8?B?MjI5MGJ3bGxsT21KSXZnejA3a01XbTkwUnZ0RTZEa2Foa3d0cjdKcm1iUW1M?= =?utf-8?B?RGEzZnNUZHRRN25ZSmhEWld0cEJGMldXdE1ZTnpTZTl5cHVJaTFJSXo3VVZz?= =?utf-8?B?OUwreWhqWjBqb2VKQWM1RmhyemZLTUlJcS94R1Bud0o4Tm1COE1GVXhVTzMv?= =?utf-8?Q?LMgWr1nQBfaaWfvY=3D?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: f9aa33d4-c252-4c5c-1b45-08da391edb27 X-MS-Exchange-CrossTenant-AuthSource: BY5PR10MB4196.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 May 2022 22:36:31.8201 (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: hLR1Z3ezXD3ASuMg3HIpe8rC2GWqMye7VIry7cxN1WXQamW6tZ2Ab7E52OUdqWv7PECW2NSn2uPHMqiEiXlKDQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR10MB1823 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.486,18.0.874 definitions=2022-05-18_06:2022-05-17,2022-05-18 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 spamscore=0 mlxscore=0 phishscore=0 suspectscore=0 mlxlogscore=788 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205180125 X-Proofpoint-GUID: _kSt_ubcV7zV11TrvxQ_GibHO2t7ycnk X-Proofpoint-ORIG-GUID: _kSt_ubcV7zV11TrvxQ_GibHO2t7ycnk X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 17215A009E X-Stat-Signature: 5fwikpi5fx13yx71jhetc8y6d4no8d8h Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=1G78fsCk; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=YcV5lKu6; dmarc=pass (policy=none) header.from=oracle.com; spf=none (imf25.hostedemail.com: domain of mike.kravetz@oracle.com has no SPF policy when checking 205.220.177.32) smtp.mailfrom=mike.kravetz@oracle.com X-Rspam-User: X-HE-Tag: 1652913372-992159 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: For most non-anonymous vmas, we do not copy page tables at fork time, but rather lazily populate the tables after fork via faults. The routine vma_needs_copy() is used to make this decision. For VM_HUGETLB vmas, it always returns true. Anyone know/remember why? The code was added more than 15 years ago and my search for why hugetlb vmas were excluded came up empty. I do not see a reason why VM_HUGETLB is in this list. Initial testing did not reveal any problems when I removed the VM_HUGETLB check. FYI - I am looking at the performance of fork and exec (unmap) of processes with very large hugetlb mappings. Skipping the copy at fork time would certainly speed things up. Of course, there could some users who would notice if hugetlb page tables are not copied at fork time. However, this is the behavior for 'normal' mappings. I am inclined to make hugetlb be 'more normal'. -- Mike Kravetz