From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 32A1F944E; Wed, 9 Jul 2025 00:15:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.177.32 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752020137; cv=fail; b=f/ZneoW0yRt7Qx0Ne4e++CanrelGW5Uz494c6NU8R2b9lTNC1+mArmazFVSD3X9uQKh9PFTYHdPjjYAuX0jxRIjbDPxeszHdIIOkavoPQL8Dqi1hNk6awjmYa+bSkz3vQV7hOTMHhdM7zC9mYkJFJKwLBSsF+faHxPV57+LHBzk= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752020137; c=relaxed/simple; bh=PP28W5yK/MXRQMeonsCxW4f6QrjhUY609Psaj9ISG2Y=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=WBqqi1lY8Czd9PDLn38y1bLMXEiZ5Cy4s6IdOKuL5NBiiREaPUw83CNPqHEzwZtJDuHJo85m0bSEi5+JS0q+tekBhnJWqYfIZBm+7tWHBvG52+9QIahQ2tgRsi51L+OFuRAS35Ne6JfZpSebCxZep9PiiJKO8ga4N8r2UJ9yZPU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=ghHMkZ36; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=yqlbetaY; arc=fail smtp.client-ip=205.220.177.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ghHMkZ36"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="yqlbetaY" Received: from pps.filterd (m0333520.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 568NN9wf021977; Wed, 9 Jul 2025 00:15:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=ZBJPSLqIu0wLKE8JgdeyExPx4KsYTnqXErcuCmehZPE=; b= ghHMkZ36hflwhbF+35/Xn4Xc0Bm/ov33YOyPORYWpEck7veAbZpqFbGkY8S3fEjP 1+s93/A97MEzo0dqUI7rQhYkDis9S0GPzsPGHy/5IzwS8t7nS7jz4fg7zYJquhos QyGu3m9Jt7Pda4VX8NY3i63RLjunCrDC1v5MmBB/xaOLACt7CoJ+DpDCQftxNcbr SZObViyGv3Cp2Ncx20sSv/WG/Hy2e1Qy1Z50ZVyimcuEFC53mZt3FAPgX9JT75Gh Hs1YublcN0iWyA6D3gcNuhjC6udxGv17Xyjr3SE68CSE6D/0R+X99LntsPtToRIu nsdjqclFH1INnz3xz+qCWQ== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 47scxbr173-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Jul 2025 00:15:12 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 568MpZQn014128; Wed, 9 Jul 2025 00:15:11 GMT Received: from nam12-mw2-obe.outbound.protection.outlook.com (mail-mw2nam12on2069.outbound.protection.outlook.com [40.107.244.69]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 47ptga9x0d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Jul 2025 00:15:11 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=vy3X9x5C7fYEU5BKvVmqiKfD8EVPPOq7FMuSEJ1praKy+SuuOFoNKUUuUEOu5HXOfcSHcyxs1boUMJmJj91tMhXaX+zPQzykOTnPRE8w/THS4H2NdREMuk9tQS2BtChJ8ZAHmtWreakMAFT0FFue/Y/7cgY0dj1bwETTqanw1tX0qJy4A3d0vk41urD1Oa6XJGDmDDlT8KcQZiafeuW2N0BIWpcL2FSnEIKCERQQruVRKXSJUiIGBiC0cY0z+1m2wROsjM/IsVtQSkZzw2yBpsplM3ZIthIj8twIY4fzYJsu23O3Jwkie6lBoRth9Em7upKVAtD579l1+ZH3UXuKbg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=ZBJPSLqIu0wLKE8JgdeyExPx4KsYTnqXErcuCmehZPE=; b=NEV6NcfBNpq8alvba/VCdpNVAziTUi26PVHfHdd30+YrvtNV1uF1lPyAmKpZaFANKf6rmd54ZZAPXDcA42qjff1CtPL3HMvZnmwLQ5UiMuh9ybLAba4TQBu98aOH28V3VkioIq9VCoSUCl6wm0kEy4Jxs/nfl4IWEnEksT+UMjvqot3q8Gmuis02CmSPgFbMsGlCgVMqlcv6+WIkCmsTxCqpKbE5acTiSWKOV4rkQVvMdPy4eRwXa7TosR3+pwx9+mNwFIkkg9IfmPq/CXPyqve4BrIDehhuj6PTNn9qSxfCW6xu5mg8/OHssjoOit7v7lWV+wf/sI9IaFf+50mjIA== 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=ZBJPSLqIu0wLKE8JgdeyExPx4KsYTnqXErcuCmehZPE=; b=yqlbetaYGxA+unGYYEHiHhR5o1E010hBZRS3jHnCh1pu5dm5rXp+1pf0y/kxtKnHUIqnYA/w3zLbbAWYsvH9EjDtRpAufJl1SijHB+k+D97XsSGwRplFJCxIQRngTwUdv3Eh+U6hEIOD0MuxeY2qoUFHuXsdmB5K5qc20RvItTI= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by CH2PR10MB4150.namprd10.prod.outlook.com (2603:10b6:610:ac::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8901.23; Wed, 9 Jul 2025 00:15:08 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::c2a4:fdda:f0c2:6f71%6]) with mapi id 15.20.8901.021; Wed, 9 Jul 2025 00:15:08 +0000 Date: Wed, 9 Jul 2025 09:14:50 +0900 From: Harry Yoo To: Muchun Song Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, akpm@linux-foundation.org, david@fromorbit.com, zhengqi.arch@bytedance.com, yosry.ahmed@linux.dev, nphamcs@gmail.com, chengming.zhou@linux.dev, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com Subject: Re: [External] Re: [PATCH RFC 26/28] mm: memcontrol: introduce memcg_reparent_ops Message-ID: References: <20250415024532.26632-1-songmuchun@bytedance.com> <20250415024532.26632-27-songmuchun@bytedance.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: SEWP216CA0047.KORP216.PROD.OUTLOOK.COM (2603:1096:101:2bd::11) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|CH2PR10MB4150:EE_ X-MS-Office365-Filtering-Correlation-Id: 982351c8-cd08-4151-a976-08ddbe7da9aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?TGMwRGszZVA5ZUpDdm9kbGpORExLQldzMGVhbXA5c2FNRTUrOXlQM1JyT1JJ?= =?utf-8?B?blFreU50dDZsZlhISXVyMTRTL2FxNXZiR1Jnb29zczMvTXcvRGk3NWxEK0p4?= =?utf-8?B?Z1NjQ3hyTU5XTmVXbWxyNHAySVVVMVloOTFXNDMweDdYTkFuSEx4eWFOYjNU?= =?utf-8?B?bkRnNy8vZGc1SXAvaERVNFdWdWxXTTFna1hOWDFIYWpVN3F0czB0cDQ4OEln?= =?utf-8?B?djI3Q2VydXhydmloREsyTkcrTzJUR2VUUkNWWGhRQkN1OFl2Rm54RXpVWGl5?= =?utf-8?B?QjNkV2I2Q012cHdqWTlwWWtURW1idXRVejR0Vy9pSHFUK1NUaXVjQXN1S0h6?= =?utf-8?B?N1BsVUpDWW4ydy9qYTVLREJWVTlOMS80Vkc3SlZFTHRwMVZvTk1ObVhvN3Rv?= =?utf-8?B?amVUQ0ZtREordTNWZ1VtZjZxcUticWNLT2swWndMdGV5T1JnWTNFUlBiNXAy?= =?utf-8?B?YjZ0Q0RGVWRucnhkOXFGdkVYOGxVREI0K3BnM1RyV21mN0s2MUtTNFYvdU4w?= =?utf-8?B?YVJKWEFsaHdBZ0hBSGEwVzJHZmRaaFNHT09zZUpQUERIeWJWeTQ3cS9zUVBu?= =?utf-8?B?ZzZXZk9RdVJwVTFDMDFCRERvSDBNWFgzTkRmdjE5RUZubVUvSnVNb3NIclNx?= =?utf-8?B?T1lYdzY3UkE5QjhOdlNmelM2ZnZVWXdTUnllK3BId3lRTmFaK0ViZWlOK0wx?= =?utf-8?B?WFFMak5tbFh6TG1RYVVGeE95ZXBVQWZTWXc2Ris4cGN0bUp3L1BjQW5DV1hs?= =?utf-8?B?T2NNWFE1amIyQnd1Y2RFS3VWUERibWp3dGNER3B5U2JzM0RCNFVlZFowMVBU?= =?utf-8?B?SksrdjV5QVVIbzF6Z1BlZWtraXdPekdWZS9hV2dmbUFUWXBUNUlwS2RINnQ5?= =?utf-8?B?TmdNOWZwTkNwTjZVS0NxWG9HeThhREhRc3ZkeENlUDBReExaVkV3TzhYQU9o?= =?utf-8?B?Vk1LQ2NOQi9TVm93NkpvRHlSdGpsYis1N3lqZjFzUytqcEJXdktNclBveTM2?= =?utf-8?B?L0ZuZGp0QW1ZV2tIazZ6UXBsdTJHMHl1ZFB6ZnRYNVZOUDFVeEZ6T3NTYmNH?= =?utf-8?B?TzZtTmFrUWN4SGdhVlZ4ZjdGd0grQ0luT283VW8zcGpDaGlIRHlwQjArN3Vo?= =?utf-8?B?bGVsQkdldXhVMlhsdmJ6OGtIbEY5dThYSjdJQUNuVyt2aG9hOUlwb3BOdndr?= =?utf-8?B?cVJmeWw5UjV4aTJHMUZBT0ZLK215QVBDcEhTZGJESDFkSEhFdGpNMkxwRnJU?= =?utf-8?B?dTlFbHNDOVFFd0hJUGZBV1I4VWtocjJleC91cWdWYXN4VHZaM2V6dllzOUQv?= =?utf-8?B?TURhdHJSejJxUm8xbEU0KzZyQnNPNUdaa1VLVExTN2NTYzRIMVhDN25EZXBS?= =?utf-8?B?OGxxYVc1eDRaK1dwMTRXZ2FrN0M5alllSFAybEk3Y3JmZW1zSE5wTDVUUHVU?= =?utf-8?B?NVBjSjlrYmthR0hBREUvalRDdTBoQWdPMmlPb0R1R0hvK0wwV0RSTkR2WUNl?= =?utf-8?B?TU9BSllLUU1PNnlBYjhocUQ3cVRqazVYczJOSUdEemtpVEdsc04wWVFZN1Vm?= =?utf-8?B?d0t0QWJkbjArYUJTcHFFYmFHbE5lMUlEaTA5VkRsVWZWZGJLUE5wUDJ6ZDYx?= =?utf-8?B?Zk9vT2RDOWpXc0l1TkdNNmpPcWJyOFp2RHdKMHRvZXh6MDlKSUQveC9rWlRT?= =?utf-8?B?K3REZjdHL2RMeWNLSFJFU3piUmxzSUJwWkZCQmw1SXJ1WWNNME05Y2lhZmor?= =?utf-8?B?ZDhRY2RuOXVDUXhabURZQmNoZmp6R2d6ZTRtVkprK3hTYTBTaGhjSFhGTnNO?= =?utf-8?B?R0E5SFpWRWY3TThhQVpqdlRvOThiK05JeXl1MmNwN3Q3V3BHdkk4czRnS3Y0?= =?utf-8?B?QjFNRGhoK0JhWEk5Q1lSSWd3YVJLNFUvWnI2TS9JL1VoaFE9PQ==?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR10MB7329.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Q2hoWm5mRnVPRmoxMGl4d1dQcWdqTnBiQ3VqS21SdHVvdHh3ZVRoRzdEZS9P?= =?utf-8?B?NXQrS00zOUtWbWxNeGx2R2c3UGZmaWN2SUNPSlFkWURhSXJ3WVFZSHJYRmxZ?= =?utf-8?B?R1lOWWVyNmtqSHhrUTlFajlOdENtV2ZZVjlUZEJuT1FBUFZGS2hsNW5aYkVq?= =?utf-8?B?S204aWRGSnNXcTlXWnpIazJlUDljQVh0S05ubUtHTFRndS9WbFBFQTFHa0dx?= =?utf-8?B?S2pxVEdWcWcxQ05KSzBQQm56aGM1K3B1Qm5SZFdxYWZ0Mk4xUHdoNmZVTnQy?= =?utf-8?B?bG5ZNTRHbFNrRDBJMXBzNTBNYld5dkhqamdjNU9UYi8rb2dVVXkzRTdYWGNQ?= =?utf-8?B?SGZvd2RsZ2hPL3ZMOXhaMkJPdmFtQlc4SnVZSnBuTWxCZWpkNXFLM3Z6WmJO?= =?utf-8?B?YW1Gc0poeDVpbFpzcVphbWJENEt5YjI5aWFKSDkwSi9ndnZQTWpHd2ttcUNk?= =?utf-8?B?ZW5ZMVNpekZKblYza1RRREZGcFVVSjV6bU9Wb3R4bm5QOXVqZE4yb1lrS3BI?= =?utf-8?B?bEZ0TGxhZE9rdUpSNVRTbXZXQ0xQU1ZCWUNoMlZJcWMyLzZMZnJZTzBtVS9N?= =?utf-8?B?Mk53YjhBYnp4MVZvTjhGRE5hY2VDd2h5czk2NU5KZnlBTmVTeVNRWnRJS2Nw?= =?utf-8?B?bWc1aVJhTDRMMHpTT2EvQXhxR0drS0RXMExHUTF2WWJxVUYydEdTczMrSTBT?= =?utf-8?B?eTJCdmwvaVY1V2IrTHkwU3o2SHpUV0JtV2FRY0JSTGxiRVVzTzE2TDQ4RE9q?= =?utf-8?B?SklRcXMySE1pQVliZUlLb3lGVnZqVTZxZW9tVkxxWlp6MlBMUFB1RHY3cnZC?= =?utf-8?B?Yk1seHVSaGJ1T3NydzBvQUFKTW5qeSt3SHY4MDc1L09OM2RuR0xRSCtMYjVz?= =?utf-8?B?czYwcFlCOTBGdXhHOWZlbzJzUHFCOEtZZHo3UG9xMHBmcmVIYWFhMCtHWmlm?= =?utf-8?B?NGhVM1g5ZEJiQnAzTis5VWRjSmFOQ2trNjY5UldSb0lNd2w3YUppOEp6QWhx?= =?utf-8?B?NnNWVm5rdjh1Mm9ReFppYjBkcGVPeFduZ0NGUmUwR004Q25iUzA3Z0NZcC9R?= =?utf-8?B?RHIxMWdrTTJwQnd2K3h1L2dsSmhKdHNYWk1RRWgvUFdrNnhnZ0t6eXkvbVV0?= =?utf-8?B?dXI2Mjgvc3NVWnh4RnltK1VrTVI1aENScXluallhd0hEbmNuSzhFUTlnWEYz?= =?utf-8?B?YnNyYVN4TTZhUjduQlUwRWdsT2RHTjVYZ0s4YnJ5eFhiTFdaNlRHVUszQXlX?= =?utf-8?B?NGxoczNJL09oNWowbzVUWXJDbUE0UFZXYnpFd0tsdFZ2OVBCd1E3Uy85RUZS?= =?utf-8?B?S3FxaUVZUDJHVHhMWExvSENieVhJbGdsdmhKU0NhcHBRMStZcjJmRXIrdHM3?= =?utf-8?B?TzZHRjI2a0pROHlsblNWUHZSZkh2VTd0a2F6T3NZemFlSUJySGM0aE0zQy92?= =?utf-8?B?NnBhZjhiN0Y5cDh6bFY5ZVpRVkp2WkxFak8wZ1ZmSlRUVVhOTVZNaktLSHA3?= =?utf-8?B?YUdiY3NRQkZTZXc4YzY2VEJqbDE0L2cwWUxxalJqZ3lMaVNjeUZpcWRSelNy?= =?utf-8?B?b1UwK3MzamRNT3Z1bW9kVkpnWFA3cW1DZW9KN3V6T0xHK1d1VkJCWWZQek5Q?= =?utf-8?B?UHZ1SExDejZKZlRMdUNNVDBBdVRGMFhycllYMVRxWHhCSFdxTHNqQ0lORkV5?= =?utf-8?B?KytlaSthS2FEY0VMY3ExUkdvOXpDY0lrUnY1OHIzU1ZJdHU4UkJ4cmYvVTlX?= =?utf-8?B?bnNTcWMzemNWZkZDTHRqL0F5bnhqVzFGb3pWTXdyaU1DeWQwcDFsV2RyR3gv?= =?utf-8?B?a0E4QlJZU1JKRWRocDFLR2xpdWN3UnZDcm5tUnBIRFNPb2hYVlBNSjFTTGpw?= =?utf-8?B?ZGorR05nTVhRMnlsNGlQTlU4N1E0TmxTVnFpaThZQ282KzNpL01PcHBYQVNH?= =?utf-8?B?L09MSWVpeE5VbUpScTk0Nys4OEtmYXBpMU1BRUF2M1NhTEg1NGVkcnV3S3Ir?= =?utf-8?B?VUtjRUJ4K2N2SnNsVlI4UkloanBHOHp3dFJ0SHhWenE2R3hiS08yZWo2Vm0z?= =?utf-8?B?WWFyUVd6S2hnUU0rczY1akJRcTRWcmwvRnUzTGV6dHNNRGlwNlR3QWg5bjAy?= =?utf-8?Q?rKNfXMaEU0a2FugqWZWkyrFob?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 982351c8-cd08-4151-a976-08ddbe7da9aa X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jul 2025 00:15:08.6201 (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: hSD+CZXJUz5NxIA+pUofvcpCRPJItjlW4TgQkgocMlRBOtLiyTH4MPIIlLCP8+CnQrBwIvHPbBSdVPL0agUJwQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR10MB4150 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.7,FMLib:17.12.80.40 definitions=2025-07-08_07,2025-07-08_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 adultscore=0 suspectscore=0 malwarescore=0 bulkscore=0 mlxlogscore=732 spamscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2507090000 X-Authority-Analysis: v=2.4 cv=Zr3tK87G c=1 sm=1 tr=0 ts=686db490 b=1 cx=c_pps a=qoll8+KPOyaMroiJ2sR5sw==:117 a=qoll8+KPOyaMroiJ2sR5sw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=Wb1JkmetP80A:10 a=GoEa3M9JfhUA:10 a=yPCof4ZbAAAA:8 a=CqMesUGD6HYyBvFlfWkA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 cc=ntf awl=host:12058 X-Proofpoint-GUID: 53yp5IhszAOMeI6tUbyUK_oyCbaMOrpz X-Proofpoint-ORIG-GUID: 53yp5IhszAOMeI6tUbyUK_oyCbaMOrpz X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzA5MDAwMCBTYWx0ZWRfX7YYsNAiMGVy6 EJdJbtzdjnZoGBz8W3rZUDX2BhY9Mlr7SrSgAN/wVm/O1+v8tbTFfpZKEiCofZyrFPXGHsVoUWu UDcRRipOihFZvUwhssSRa9HcxOWYQFxYddTmzNS0y0TC/2m/GKoVvE1VG/O9HLNYjOtHbJFdW4w bEH2eMFAXVqFzEfFPjKi+KbFgxEq5+snziGa2YinK3WaEfK0eITxjv0p0IunJBkfM9Ys9dCQKGh NYlmjVT6IxhZPUrY43eFpLOMMMVzfmSYOpUc2F346hJk4tFhVEi54H7xeVW5XekUudvbxGBsUR/ pTZ7mntAUh5RwaEhDhk5X4hVygiU2uNVqg7JH+xApCOIfn8Uy0GeqaWpNG64pp8P8j7OtyAQvno fyAn/B41RnsP0BEEv5zKAY50pKNy3LiQeX2LHZue++LeYvE6WAo8q5j7s2SNhuMbSU2BeC/u On Mon, Jul 07, 2025 at 05:29:22PM +0800, Muchun Song wrote: > On Wed, Jul 2, 2025 at 6:13 AM Harry Yoo wrote: > > > Hi, > > > > > > It seems unnecessarily complicated to 1) acquire objcg, lruvec and > > > thp_sq locks, 2) call their ->relocate() callbacks, and > > > 3) release those locks. > > > > > > Why not simply do the following instead? > > > > > > for (i = 0; i < ARRAY_SIZE(memcg_reparent_ops); i++) { > > > local_irq_disable(); > > > memcg_reparent_ops[i]->lock(src, dst); > > > memcg_reparent_ops[i]->relocate(src, dst); > > > memcg_reparent_ops[i]->unlock(src, dst); > > > local_irq_enable(); > > > } > > > > > > As there is no actual lock dependency between the three. > > > > > > Or am I missing something important about the locking requirements? > > > > Hmm... looks like I was missing some important requirements! > > > > It seems like: > > > > 1) objcg should be reparented under lruvec locks, otherwise > > users can observe folio_memcg(folio) != lruvec_memcg(lruvec) > > > > 2) Similarly, lruvec_reparent_relocate() should reparent all folios > > at once under lruvec locks, otherwise users can observe > > folio_memcg(folio) != lruvec_memcg(lruvec) for some folios. > > > > IoW, lruvec_reparent_relocate() cannot do something like this: > > while (lruvec is not empty) { > > move some pages; > > unlock lruvec locks; > > cond_resched(); > > lock lruvec locks; > > } > > > > Failing to satisfy 1) and 2) means user can't rely on a stable binding > > between a folio and a memcg, which is a no-go. > > > > Also, 2) makes it quite undesirable to iterate over folios and move each > > one to the right generation in MGLRU as this will certainly introduce > > soft lockups as the memcg size grows... > > Sorry for the late reply. No problem, thanks for replying! > Yes, you are right. We should iterate each folio > without holding any spinlocks. Wait, did you decide to iterate each folio and update the generation anyway? I assumed you're still in move-folios-at-once-without-iteration camp. > So I am confirming if we could do some > preparation work like making it suitable for reparenting without holding any > spinlock. Then we could reparent those folios like the non-MGLRU case. You mean something like take folios from LRU under spinlock and iterate them without spinlock? Anyway, I'd be more than happy to review future revisions of the series. -- Cheers, Harry / Hyeonggon