From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BN1PR04CU002.outbound.protection.outlook.com (mail-eastus2azon11010023.outbound.protection.outlook.com [52.101.56.23]) (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 8ADB52F361B; Thu, 13 Aug 2026 19:27:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.56.23 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786649278; cv=fail; b=JZV36xnkqmbbN7YHa6mjRV8fwkvyXOH1EVCpCtIns0o0QYcT9z+tnejTBnwI5IGtUU7vsX3Rye26CeVuGkKBfIyOFRN2HZqgtHcjiMj6fsq2Vyqye8xTWaUlaavR6Qx0osMX9K/82J3rskJU+hs3I5l7T/HFHlVyN1oyaR3aCMw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786649278; c=relaxed/simple; bh=OkeD16DKVeyhCX+ZmsphNcmK48EUEjYSXsNJroPMMLA=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=LFcaT6bYn2pSl5iUuVXeNLoyim7N2V/mafN17pJ9sWqmR38f8SU9Bcfu/zgE5JB+2sbj/GPmbrygW8HGkUuuVkRSUlA1tDv4LeNIexdBk4Z9DxL7Xl5uidxBLHQw07mMn9K+IMk8CGWBTBv2t1AG2CB/qVRBRKUlK5kx6SJtDiY= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=fp7qXNLl; arc=fail smtp.client-ip=52.101.56.23 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="fp7qXNLl" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=e/b5Mndb4U3sF1Ab+y9Ai5XjL/VV4yQ/sxDH8TOXG0R+l5q5x3fOoQqg2TnWbqRFZyTfiziFhBVBLxpxTfNOhdXuxOLF6BMDA5RK8L6jcyiIxnUJEGSNnNvZ1MzpmWXMLWuCP07V8jiUX2cz5XH++UlK2Oe7xLpS350xgb7JxVSDuateY/Gmjvl0fsR6ZckgUC8WtyJchAGgrWsQPYcwp14FMv/CHWulk09kWs6evRE08RSc9zaDVvy0tggHcfekQp7DhNFPlxjV97JXHog89grxHxfnNjw1WV5oi6E8Ydvk5wzQUIK2/a7zbj1UpHtSqex51WSSGVi3OM3etHy8Jg== 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=mBoKgDZqsjlqgh0lNVhLp1lGT4E2ahF0Mbq7YMMqRwc=; b=fLmMKSXK8mtQucQF/ANkxULVfXJMy9vk33AeBEukE2eqimeZW+Pfl5NF31MYkzInZ5tK7lCwwoQZiKqpzlUdSqjg3Ehw5F6uYKy7ZpsvEaj+y+czFih8obRs3MGb4DBitKfX32ggyv3rNNB9drNBFgynu7jr+RXXyYMhMdZwTM+4CNZibFaz2x+yS39V4tucBBOIQa73zQqxk30RGf2V9vUFN4167DQ52V9HHIUpt8V4GcNwSv7MRTNPfRdB6ZR27Iw/v/v4jPQn9zZJV2Dj4rNS/CUgaivePZKnzX9ggQffDAy1QHgz5JmBg0Qo/Rg7u2zfB8ptBS7uS3fRhBNS2w== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=mBoKgDZqsjlqgh0lNVhLp1lGT4E2ahF0Mbq7YMMqRwc=; b=fp7qXNLlbn4CcQp2fU7ryc06Zd4lwzO2mUdMs/kp9B1+BbFEkD2dD7Ip9Ld5LAIO4ozBa2qHr8nwLIql2t5ymCDb/ESss6lFJL8BywDhEzz/j+gXCzv5xNe2edjtLbDrXhwc66eNRtCJwG/slfd0eHRJjCTn/SUKD1hCdUQk92U= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL1PR12MB5320.namprd12.prod.outlook.com (2603:10b6:208:314::17) by PH7PR12MB6739.namprd12.prod.outlook.com (2603:10b6:510:1aa::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.315.13; Thu, 13 Aug 2026 19:27:50 +0000 Received: from BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1]) by BL1PR12MB5320.namprd12.prod.outlook.com ([fe80::1876:4a6d:2cf5:b8d1%5]) with mapi id 15.21.0315.012; Thu, 13 Aug 2026 19:27:49 +0000 Message-ID: Date: Thu, 13 Aug 2026 14:27:44 -0500 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND PATCH v4 09/15] fs/resctrl: Introduce kmode_cpus/kmode_cpus_list per rdtgroup To: Reinette Chatre , corbet@lwn.net, tony.luck@intel.com, Dave.Martin@arm.com, james.morse@arm.com, tglx@kernel.org, bp@alien8.de, ben.horgan@arm.com, fenghuay@nvidia.com Cc: skhan@linuxfoundation.org, x86@kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, akpm@linux-foundation.org, rdunlap@infradead.org, peterz@infradead.org, feng.tang@linux.alibaba.com, dapeng1.mi@linux.intel.com, elver@google.com, enelsonmoore@gmail.com, kuba@kernel.org, ebiggers@kernel.org, lirongqing@baidu.com, seanjc@google.com, nikunj@amd.com, xin@zytor.com, pawan.kumar.gupta@linux.intel.com, tiala@microsoft.com, chang.seok.bae@intel.com, kprateek.nayak@amd.com, prathyushi.nangia@amd.com, kim.phillips@amd.com, naveen@kernel.org, darwi@linutronix.de, elena.reshetova@intel.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.lendacky@amd.com, eranian@google.com, peternewman@google.com, qinyuntan@linux.alibaba.com References: <27afa5e408453c93790e5aef61fda31355d96ec9.1783461016.git.babu.moger@amd.com> <13834492-22f1-4135-8c57-74052544ed17@intel.com> <98568620-7e61-4d43-b72c-5866a7d3bca1@intel.com> Content-Language: en-US From: Babu Moger In-Reply-To: <98568620-7e61-4d43-b72c-5866a7d3bca1@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: CH0PR03CA0421.namprd03.prod.outlook.com (2603:10b6:610:10e::26) To BL1PR12MB5320.namprd12.prod.outlook.com (2603:10b6:208:314::17) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL1PR12MB5320:EE_|PH7PR12MB6739:EE_ X-MS-Office365-Filtering-Correlation-Id: a7101420-0d14-457f-1884-08def970f588 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|23010399003|7416014|376014|1800799024|6133799003|56012099006|11063799006|5023799004|10067099003|4143699003|18002099003|22082099003; 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:BL1PR12MB5320.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(23010399003)(7416014)(376014)(1800799024)(6133799003)(56012099006)(11063799006)(5023799004)(10067099003)(4143699003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SzBKczNybi9CcVI3dEh2ZGE5UmN4aitwRTAreFM1RXBhUlhPalRna3ZvVTcv?= =?utf-8?B?NDQyZlltUmJFcFFBQ0lsKzBBbk1XWi8wandkci96b0tNUFlTYmpKVEw3Y0RI?= =?utf-8?B?RDdBSWZSY1VzVTUxem52T1NSSHI4NnJsZWdVb1pzKzk5YjZNbmIyaWt2M04r?= =?utf-8?B?bkVycmRoOFFrUzJXdjMyVFFCemhKUllRenFYTnl2Z0FSYkRXNU5KV2pBM0ov?= =?utf-8?B?SGFRSSsrcDhTbXY5K2dibUpSeFJWLzhhZEpmcUtWOFhBa1hJNE9UM2lQSk5w?= =?utf-8?B?d0xhWHg5RXlQd0pIaG1oNVFzb2ZITTlJZzU1ZlZHWjZZOGFpb0VnaWtFbytW?= =?utf-8?B?endCVjgrbmFURnBFQlg3Lzlta0dkOUllV1dKY09sam82ZjE4bncxak5KUFJC?= =?utf-8?B?ZUdYN0VCckRFYTZ1MDNUSXpGQ2VJeEt6SUtZMkRueGptbmhwaStpY1RleUJ0?= =?utf-8?B?KzdMa2lxbGdvbXBOdzlQSjQyVWlDOU45M0IrcjJMbllsS05xSGFHTVl5bi83?= =?utf-8?B?R1hSVnBhek5YNUV6SWdKTjZQaEZadElzOG54N3E0NHh2bHRqVjR6aTJpNndr?= =?utf-8?B?aXZwYzZiKzA5TXdwRmZjSHdkL1dFcHhzUHlKVVpIZ0JiUzlIblB4djlKWEJ2?= =?utf-8?B?d0tVTWRBTzYwUTUvUkNMZDlENDF2VVRTUVU4UXZVQUlaSWNqeDgzL3o2bmlH?= =?utf-8?B?bU9Gak9zcXRpcm1QYStVbjdwSVNibFJza0dTOEorV21KZnpUNjJ6aGlvUTBk?= =?utf-8?B?alIxd2pzZVZPbkZsekJBOTFsdExkZnFIYVFGTU1LQjc3UFlCTStVakdPeVFU?= =?utf-8?B?Mk8zL1JiSzVBWUlVRG1iOE81S3V3c2cvZ3JWVXN5KzQxbU9oR1NMRVU2SlQ2?= =?utf-8?B?dVhCOXFlTjI4TzdmKzV5dWdRcVQ0ZEcwd29PTy95VUhzSDBaWEJkVGhqT0to?= =?utf-8?B?Mm5OR2tBV0hTeDFtSGZNR0lrVDBINGlYVVJIQzBndVVaWlJBMGY5dlJibENU?= =?utf-8?B?SUI0ajdYRDkvWnhVUXAvY0hjc2paTDFUbmNiazFaNnoxYlc0MXdmSDNTL2h3?= =?utf-8?B?MFA2V1BSTjlCekZ0d045WXJtWTNjY2VNdWVtVGdoWlVxRXQwVjIyWGRBcWFQ?= =?utf-8?B?cnhFSXl3N3NwSXliZWhLZjc5VVQxeS9Qc1loUkNjeGE0MjE4VEFHckd5emlz?= =?utf-8?B?ZmdFSHpRVXpGb2N0NVdya2NOS3MxWlVyQTV0eUpHNVdYeDdZOTFicHdvM0ps?= =?utf-8?B?S0djbVo5eSt2UXhWdDNvbW1iR2grdEorejI4VkRNZDd4UEFCN0VKUE5PV0Q0?= =?utf-8?B?M0xINTV5YzhWSEYzRGwyOFhkNFNhMlZGd3A1bWdxYi85ZU13aXQrY0R2OHNq?= =?utf-8?B?b0Jpa1Z4dklINi9aWVRxN3ZlUG5zUzltdzFwWGFoVkxPbkUwQ0pZZWEyMWxT?= =?utf-8?B?YlErdjVuUllWd3F0dDdMMWRob0E3eEluYkZYekExaFVzZ21KVG5kRTVhNzhz?= =?utf-8?B?bTI0NDhNYktpSEk4dlpzajhlZGlaVFBPMWh1ZnJ0Q2VaWGova1JORmNaMWdM?= =?utf-8?B?S2RGN0ZKSmFESnB1M3I5RXFBSngvYUQzV1RaeE5mSHZYcWRNZTBzbE90N05i?= =?utf-8?B?VDBHdkx1QXNHYjRldjBZYjdIRlBpcktXYVJydzRIZnpFaVdHalg2anF1TER3?= =?utf-8?B?KzRZZ0xiKzNkNjFvU2dvTk5KQVdZU1R3S1VJRHFlaWZUZUdRTGtndEk4ZHZO?= =?utf-8?B?c21ZQXgvOUhUcFhtbENHVWhKaWowQkZSb1JmdkUrbTdZdHBCTEdRVUQwU1la?= =?utf-8?B?cDJuTnVZMytRUW55UzNWaGRtOG5JNmNLeEMwVGkzUHdjamtUb1BmWEFyMDRQ?= =?utf-8?B?YmZqSjVXVzJCWU5jcFRlNUl6a0FvU3YyQzZRS1hrdFRzV3liT0s1dHpVdzZ1?= =?utf-8?B?MzJDbDMwRHZKanE4QkI1Z1A3QmZkWThSR3F2TEU2VitmSXRjNC8xUzRBZHBu?= =?utf-8?B?dXNlS2I1amFGamQ0SkR6R3ZpWjFHNWFSR2pEbi8zMy9GOXFBaS9STmRZZGc5?= =?utf-8?B?Q2dXcDBDdW55bnFyZlpPV2dLY3V2eitQaXNod1NpL3VadFNSRkVwK2JuOXVK?= =?utf-8?B?TDhTSkpyL1BwZTBIODUzTGRlRy9Mdm1qekQ0RytwamxIQ3NzNkNxUWdEbWx6?= =?utf-8?B?Vml3T3FuSEdjME5JalhiWVBFRFRkaTZ2NTdISmdqK0c0UlU5ZUVsa2dzNGND?= =?utf-8?B?K09vR3dmYjdnUklsSmd2SWliVk5oS3B3LzRHNW5BbW5RaE9icHhCaTg3YXA4?= =?utf-8?Q?sBHKWUH6yuEtWsuitp?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: a7101420-0d14-457f-1884-08def970f588 X-MS-Exchange-CrossTenant-AuthSource: BL1PR12MB5320.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Aug 2026 19:27:48.5907 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: H33EZJgGzjiRDabRu1pQHYvf9yd0UKG3HRLZrBstWrJcFjVaZQczzXXBWpfeh6/I X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB6739 Hi Reinette, On 8/13/26 13:19, Reinette Chatre wrote: > Hi Babu, > > On 8/13/26 10:57 AM, Babu Moger wrote: >> Hi Reinette, >> >> On 8/10/26 22:20, Reinette Chatre wrote: >>> Hi Babu, >>> >>> On 7/7/26 2:50 PM, Babu Moger wrote: >>>> Kernel-mode resctrl policies allow kernel work to be associated with a >>>> specific rdtgroup, optionally restricted to a subset of online CPUs. >>>> >>>> While user space can query the active kernel-mode policy and its associated >>>> rdtgroup through info/kernel_mode, it currently lacks visibility into the >>>> CPU scope of that binding. >>>> >>>> Introduce read-only kmode_cpus and kmode_cpus_list files for each rdtgroup. >>> >>> I think it will be easier to follow if this is deferred to not create these >>> files in all resource groups by default. Instead, at the time they are >>> created it should be obvious that they will only be visible in resource group >>> associated with the active kernel mode. >> >> I am not clear on this comment. Do you mean create these files when user associates the group to kernel mode? (during rdtgroup_config_kmode) > > No. As this changelog states it creates these files in all resource groups. This > is a confusing thing to do at this point in the series since these files are not > expected to be present/visible in all resource groups, only in a resource group that > is assigned to the "global" kernel mode. This commit mentions nothing about this > usage and thus from reader perspective does not seem like the right thing to do here. Ok. Got it. Commit message is not clear. > >> >> Also, you mentioned about rftype::create_hidden in >> https://lore.kernel.org/lkml/0126a5e5-48cf-416f-a21b-c231a703c18b@intel.com/ >> >> Can you please clarify on this? > > resctrl has centralized functions to create files. For example, rdtgroup_add_file() > that takes as parameter the properties of the file, struct rftype. With a new > property, for example rftype::create_hidden the file's default visibility can be > set _at the time it is created_. This simplifies the code by not needing to sprinkle > changes to these files' visibility after the fact at the various places files are created. > > One patch can add capability to resctrl to have a file property indicating that the > file should essentially be created with KERNFS_HIDDEN set. > > This patch can then follow by using the capability to create the kmode_cpus and > kmode_cpus_list files in all resource groups and it will be clear that the files > are not exposed to user space by default. Soundd good. We can do that. Thanks Babu