From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CO1PR03CU002.outbound.protection.outlook.com (mail-westus2azon11010051.outbound.protection.outlook.com [52.101.46.51]) (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 A2809353ECE; Wed, 11 Feb 2026 23:11:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.46.51 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770851463; cv=fail; b=t27vD7/lKsVKevgz0vinXmyW/h+WmgfNy+IrlHe3JuWY9LwQeTsGJ1uDS5majjYXnf3A4FOklb57cgZZj6ndWzdRsWqeG4NQxmedUuEBFTWib0l0ZEplnvzfzA+P7VpxpWHZD7Qdm4okqvqMXyCRb4oIxdD5ZB+YXgd+Nxpl+Qc= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770851463; c=relaxed/simple; bh=83dukreWEsxOcfCbi57t6bFOg9LJG5Sk6ttr8mKb+HE=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=E0sfgOiPIHEjR2Dg0LhAn3xg/rFP8VJjUF11bmIlTu45EIiJ9KQkbg5mjO5fH7WUoPvzoYywUVzsSsbPFjG0b9RBbKs2WRzncbYlMGcnRy2NWxje+YjQnqe60g+/2Xzww9o5Xe2CtIj0a0OXvHLXsbgJ9wYiMo+DaCbH+JNdc/c= 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=NGsx/P2C; arc=fail smtp.client-ip=52.101.46.51 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="NGsx/P2C" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=hPh0856jEMRyZeY3BZRAlOGZXCdRV63Hk/rM2S4HzfWo93AAZBELJKsCMZqM3EXZcbQhxRkGTBHrngCq7IbGnZeuUURF3gij9twUt9MGP0PGosBaLvha/w4Y4unA1xuzl3ehItT86+m9QmYxyp+aSbTK2Nf7jvJRdGVJqc+SWG50KKPCYiNh543+yorEImSKBWLaBIIvfhyNhVJXEy8XdZMzPqVGwJOBCBqFdcmTOeH8uzfwVvnVlOotUgxWfyUsNZ/Rr8D0+t4X/DrGFchN5ND9/oN7XDpCYMffAw7rjxZcxX1pFqQTz1IGJq8wKH6YajpfilpWFpMVd9fF17Fyxw== 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=5EYmDkrEHqFTkDJigGjC5NzXomWQwcISZSzbTEeTWnw=; b=rOreRLttMHvjZQksMGNInnbpqnG/Fqs8GcPg67pbi2SmEg9WVcc2ZCZPo/iyZnf+ZxfGWyT5vNjWQyFWLAMC9Q9Yp2q3cylMamR73Xaq5VaTAE5gQPDT2z0wiPZr8aFXm32M4iF6grJGSW2cI0XP0KqS3FSeE0Max3l6f1ayDbyb5TS5AJXRNvEhbjVyLLwjKc4txJfBHz3WH1PEcnGQ8WIZdIJfTcJAG3xXEUojtYp5aMJLAhtNFDpWDadNwxcGF9Sp5htcgocscbrSNbRCAK9vYUHHsXyLMSKgFR1z8EI5lQ3YYlheFuPvQ7xTINOOQigwMkvgXBS8m7sxzZNr3g== 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=5EYmDkrEHqFTkDJigGjC5NzXomWQwcISZSzbTEeTWnw=; b=NGsx/P2CY0FZnJPYC2x+U2nIZ32wWnE9s2KEVhDpqEPwbfz1h3emMH9lGdebYpM8FFzeF5pbYaRF8CPPd58RjwZZu/RTiOFoy9N+endrtozxI/neYBVp8MqFm6j0SY/OAOoRdFL8Fj0z8XjfqG7yFQywuinZmAGgmvDCTNfoHyg= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from IA0PPF9A76BB3A6.namprd12.prod.outlook.com (2603:10b6:20f:fc04::bdc) by SJ2PR12MB7943.namprd12.prod.outlook.com (2603:10b6:a03:4c8::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9587.20; Wed, 11 Feb 2026 23:10:57 +0000 Received: from IA0PPF9A76BB3A6.namprd12.prod.outlook.com ([fe80::4d0e:603a:42fc:7c0]) by IA0PPF9A76BB3A6.namprd12.prod.outlook.com ([fe80::4d0e:603a:42fc:7c0%3]) with mapi id 15.20.9611.008; Wed, 11 Feb 2026 23:10:57 +0000 Message-ID: Date: Wed, 11 Feb 2026 17:10:51 -0600 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 16/19] fs/resctrl: Implement rdtgroup_plza_write() to configure PLZA in a group To: Reinette Chatre , Babu Moger , corbet@lwn.net, tony.luck@intel.com, Dave.Martin@arm.com, james.morse@arm.com, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com Cc: x86@kernel.org, hpa@zytor.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, akpm@linux-foundation.org, pawan.kumar.gupta@linux.intel.com, pmladek@suse.com, feng.tang@linux.alibaba.com, kees@kernel.org, arnd@arndb.de, fvdl@google.com, lirongqing@baidu.com, bhelgaas@google.com, seanjc@google.com, xin@zytor.com, manali.shukla@amd.com, dapeng1.mi@linux.intel.com, chang.seok.bae@intel.com, mario.limonciello@amd.com, naveen@kernel.org, elena.reshetova@intel.com, thomas.lendacky@amd.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, peternewman@google.com, eranian@google.com, gautham.shenoy@amd.com References: <6fe647ce-2e65-45dd-9c79-d1c2cb0991fe@intel.com> Content-Language: en-US From: "Moger, Babu" In-Reply-To: <6fe647ce-2e65-45dd-9c79-d1c2cb0991fe@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: CH0PR03CA0182.namprd03.prod.outlook.com (2603:10b6:610:e4::7) To IA0PPF9A76BB3A6.namprd12.prod.outlook.com (2603:10b6:20f:fc04::bdc) 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: IA0PPF9A76BB3A6:EE_|SJ2PR12MB7943:EE_ X-MS-Office365-Filtering-Correlation-Id: e71757b3-7b69-4cb7-5e95-08de69c2d005 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|921020; X-Microsoft-Antispam-Message-Info: =?utf-8?B?RnphMGxvaWNsNGg4Ym5sbEFZV0tyUU0vWHlYbndxQ2hYQzlhcDdZY3BiSjI3?= =?utf-8?B?aGVaQXFYMjE1bTVMY1lkWkRHeVAxMHErTmhQRlQrMkFOR0sxd3VtMFd6aFhK?= =?utf-8?B?Wkw3T05VeHJNdTBRYXpuYk41VnhBczhXNVZvS0lYcERhazQ4OVdQS0RLbFk5?= =?utf-8?B?UTNQZVdjOEhrZzIzWVJPNFJ1MkJ3c3B0UkFwTUpiSEJaamE3WmhXcWJjc1o3?= =?utf-8?B?NDFydGdkbDhBUGhhaFY0eTBhbWU4ekFOQ1ArTDlRd25rS2Ftc1BMd3ZkWEFB?= =?utf-8?B?d2c5ZGxRS0F4WVJWMkdjeHJhMUhJZk15blUvakNZck9OQ3lrV002RWZNWmlR?= =?utf-8?B?UUY3cWoyR2JRMlN2aDFjcGtBS1hPcXNGM3JLOXIxRllPSFU4SUR6YnpZSmsw?= =?utf-8?B?QkZ6Vzg0QUs1NHcvYjgzOThVRHFDVjljem83MDZCK0c0TE94aTRwNUNzUjlk?= =?utf-8?B?bTh4aDBrU0pna0wxY3VWL2FVQWNocm9HOWxGbkxwb3c2amNUL0RGR2Y4bm1F?= =?utf-8?B?YlJUKzNXMjhTS2ltYnJUR3BieG1IMFZJSXVCYXBKRnFKK2pjQnVpSnpEc1pM?= =?utf-8?B?VjZUU1Z5a01vZ1d0TTNBcjNMa2xocG1tN1JveFdMcXRhRTZNbGJqd0Y2T1VF?= =?utf-8?B?YU5ZSWtRVWVUYXNsanlHdzNoNU1GZVVUWGRnN1BiUlYwdnByS0VjRys4VXR2?= =?utf-8?B?emlVckhMYjRPQ09LS3NXMm0zREZrOTJ1Z1RTYnhQKzNZSThaVEJaaTZVdzlk?= =?utf-8?B?RXVOZVFpV3hoTUFXOFA1UlpLQ2tXekFuODBXbm9mUE1TL3dPSkc1UzVaTms3?= =?utf-8?B?SXk5S21jNGN2b0hBSzJvZ0Y1Zk15akVTUDB6Ukc0UVR5ZDdlUk9PMVNZR1VI?= =?utf-8?B?ckI5SStmOHpaZ2gxOGY2dmN0WlFWQVJxejcrUG10L0pkaGtIV3E1QUxZKzNa?= =?utf-8?B?RVZyQi9DTjNidDBDSzBPbHVjT05tNmtuNnRaKytjL2xxeDJKeERlOE1LWVpO?= =?utf-8?B?Rmk4ZDZnN1paYWFnN1Y0WCtNRlNROXp2dlg1Z2pmSE52NzE3L0JRNG03Q3Vq?= =?utf-8?B?dnhlS2F1aER2WTBLdzcrUjNMOUVNK3ppcEMrbCtIRTVDdEQ2TXF2eWFJMktP?= =?utf-8?B?MisyYkR2Wnl1T2VUVWIrU0RLUHRUVEUveU9PNHhuRzFiTDdwQUZtbVczN3Vs?= =?utf-8?B?bStPM1ZuS3gvZ0hiYzg2SjJJV3gyU3I4NEYyWjhlUWZTbkZrMmJ0UStvMzJG?= =?utf-8?B?ZU1BRU5hZVhFeU93SVptM3NkeWs3OWpqb1JRNDZvSGtDeFozNUxYb3B3WVhw?= =?utf-8?B?RGc3SUVOc1pEY29wRlRZMllOVTkzd2NWKytXNnpTUDV0RWRwMUJaaVAyZldF?= =?utf-8?B?NGJQMFFVZDZ2OTJjSlQ3TG5aNWhRZlA4WTkxVUZsTENIRjN4Sy8rNTI2dzBo?= =?utf-8?B?YnBZN1VQOE5idmNtek5tdk02WDMvaFFSSEFITzl2Rnd0dkdSTW5EWUhvMkR6?= =?utf-8?B?c1lHTHFJWDVvYkhUdzcxMEtiL0Y5ckxDUDdhYXFCNWNOU29UTFVQVENzSEZ4?= =?utf-8?B?YzRiMXY1aHo1Z25keENWb1pWaS9HT3ZleVk4eWwzeDc4cjkwMnN1dUJYS1hm?= =?utf-8?B?YmNoM0ZWQ1Z3eWNvVGZkakxoRmNjc1hlcUE4K2VyV1EzcW1aMHhvNTFsdXNr?= =?utf-8?B?aDU0dWFzU0FyeUt3NGhwenJtT0ZFM21LR1hqUmtOemcrazNvNktZOFAyWVEw?= =?utf-8?B?aldRUDU0cUdwdGljOGQ2TlVsaFJOUm4zUHZYQ05Jdm1aT3NmUEVFZy9PSmpH?= =?utf-8?B?cFN2aXkxUXBnc2RRcUJFRTNaMUVTREhxQTNBVzM1NFlnWUFya0dqS3RBNWNE?= =?utf-8?B?Z0psdGxFbUhIdjlveCtVcnVjYnpqMWFFTkRtdXFwbDZmZEhwOFhRcVVOMVQy?= =?utf-8?B?cjl6dmhNdC9LR01KdWsrV2k1SUpwNEZJK2QxR2JRVFh5dUZGdEZGUUFzWnNl?= =?utf-8?B?NVIwL2dNQ0ZEWU5EUzdNMGxrcVRrM0YzOWI0dEVTN0xHaHlMTkMvSlMvLzk2?= =?utf-8?B?M2R6SWdGd1h2NVN1R1M0WjF1MUNrZUoxZjY5NDF5QWtqVHJWYVFNbFBrMFlp?= =?utf-8?B?QUpaUlh6a29WSlNnVnVoU0hOWDg1SFdoN1RwYkxxbDlueU4vWWZtTnFzZDRU?= =?utf-8?B?dVE9PQ==?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:IA0PPF9A76BB3A6.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(366016)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?MU4xZmlYWUc4eHJhdkM0Kys3NURkOVdneTlZQURZL011cTU4UzNuRnBmUFV1?= =?utf-8?B?MnFJbEp4M1RNTFRxN1VUN0E1MHM1Snh3MlNzSHM3QkQwV25RZ2VPViswUFpD?= =?utf-8?B?NjhrcXJzenlBenY0SUsrMXN6dGpvVXVhT3hQZUhVTTBCRHJzUU1ZcjF5dFRi?= =?utf-8?B?aURGQ2Rra0JuRUZzYjZQS0liNlBvRXk5dFVLZldCSjF0cCtjWkl4M0ZhSnh3?= =?utf-8?B?Yng5WDRUL1FsaWlrOW1BRHVTc2xDcjEya3JVSmUrcm9MMEhjTUk4RW9aNHkw?= =?utf-8?B?N3dsUngya3RscHEvQjFCY1VTQVFuMmRRL0JwenRuWEJkUzZuU0JjUjMxZmR4?= =?utf-8?B?N3ZieFREeHBmUnNRdDVpa0h0dVAxaWtJYUFxZFB0dEV1cDdJSTloMURCbm12?= =?utf-8?B?OXkzblczYnRac2xVTjNya3Y4Q2dvaVNXY2Z5cWsyRXBndjZyT1VBR29JYXJt?= =?utf-8?B?Z3JLN245bklLTDkyU0xjcjJZbGV2dFhsbEp5eTkxYjBRbnJyUi9IQ0x3QXBH?= =?utf-8?B?MmRYMVV2eEs0a1R2QWJ4RGJwY01YeVpxeHJyaWQzanp6NDhyeWlhQ3pHdGc0?= =?utf-8?B?dUtySkp4YzQ4QzlWcExLUzZLY2VSMDFOcHVFZDhzVjNYdXlzNUdaTEJOaDJw?= =?utf-8?B?ZHRvaWNHeE1CVjMwbm4rSktleVQzUjVTcnlLOFFvUGFMMXNibCtrNVFlUkdB?= =?utf-8?B?OVdZZHdGSTRnRjMwWnVSUVRJeFBJOGY0dnA5MFhDUSsrS0JaUFFjbUtHKyt1?= =?utf-8?B?bll3M1JuNmJPK2N4WnV5eG1Zc25qNlhVL1IrWlR5UlZjZ3kwWGRVZzN1bisx?= =?utf-8?B?RFRPWllxK1hieDJJYmgwMEd0blhRQ1pmOHFtVFJKbzNLdVd4V0tIcnBsV0VL?= =?utf-8?B?VFI3VS9tRzhqamFKbWtVLzhlYlFuQnZscDVnOHJNR0RiaVRvVmFEdzhrVGkv?= =?utf-8?B?SkxQRFoxSVpCT1l3ZHFQZzdJeVF1eTlNY0h5aHl6WlB0NjQyVUxPNG9lcnIr?= =?utf-8?B?aUxyVzhBU1h4VjMyK1JMb0JxU015M29OT0IwZzR6TUkrSURjSFE0YzQzaldk?= =?utf-8?B?MWdhRVhRaGdPWkFFMldybDZNNExaQWVwSDFrYUFSa1JmaFByOThlOFFoNDlv?= =?utf-8?B?R1VaMDhqa0dHUWNPbThRZ3V3ZTAydXFCdnhpU25Wb3I3Q0RMaVdRM1VZemkz?= =?utf-8?B?aTBsTGo1M1FmVHFmRUNkWS9WM1FSYXdHaFNyaWtvb2wrQTl4NUVvUkxyNFIx?= =?utf-8?B?UmJTeFBFZndWUVMzeE5aclFhb29HN1hEcmJEbHJabHMyZVJQQWd6Y0U0UjNG?= =?utf-8?B?VGJKdGV6ejJISW5zS1dqdStMcDV6Mk9jYWZTMG92YnEyWVgrbUkxVnJmMHlz?= =?utf-8?B?NytKdzIxUW9XZWdmTFk2a1J4YUxkN1dtV1JrZ0FIYUhrZFc4aUtocUowSXdH?= =?utf-8?B?T3RXM0tQd0ZQNDZsdkQxZldYUXNmL0FoL0UyTkhxNlNGaitJNzNvTFJ1M1lQ?= =?utf-8?B?b1VmRFVHd093K0hKOEJrQkh6ZXFhRmZ0WkFhU0FmU1FBQVlUU09HUHlDOXQx?= =?utf-8?B?WDB1T1ZoMlRkVDhZYXlhWWhiWkZhMDFWY0EwWnEyazh5QUtLSUJwZ2ozelBU?= =?utf-8?B?SkUrR2x1M2c1bUoyZGlWOFR3eUcyYmE1U0FrUVMxOVNHY016RjVTdldIZ2xQ?= =?utf-8?B?YzZPODFFUzluUEUyVUJzKzBxQUlZY1R3eG5BUDc0bFRhb1ZhNzVRRXlxeXNz?= =?utf-8?B?cWdDdFlYTS90R1IvN3pQQUFoWnlKWndnQVJvTWh3OWg4MTdtbW9BZm9scGpT?= =?utf-8?B?bitJVjlkWWRpMm1aM0MwQks4K1Z6S0hHNG81MkwyekxkWEovYVEvTFhudW01?= =?utf-8?B?YzBxRXEzaDVrdHpFUU5qSUVkci9rWmpkT2UybURKZ1VVbFhxZDdKSXNNVUUx?= =?utf-8?B?cWY3UmptcnY3cTFJMHUrQkV2ZDZoaUxYWFpkQ2doTU1RQ055bjZSY21VRVdS?= =?utf-8?B?c2tvamhSRG9PRUJ2OGM3dmFwMFd1NGVicUlXYS9GYTFOZHQ3c21jV1k0L1Q0?= =?utf-8?B?Q2M0QnV3YVhEaDJWdVM3L1R6SFFYS0lMY1VJZmxaYy96MjBBVjRocmZLM094?= =?utf-8?B?RlYySklHK1FuZWhWL3Q2RnVONkgzejJ3YnlqSHhrKzBuZGwzNjA3WlVkbmRT?= =?utf-8?B?cUtvRjg2aFAyTEZEUXJFYkg0U3lYa3pkRVk2Vkp3aE91NHpJU25scXdxN3lq?= =?utf-8?B?RFMrTDBTdU1rVVU3Snl5U3NNU0p6eEFWZXFMdlVwQlo2Y3JYdXFmWjk3NG1o?= =?utf-8?Q?RWkc1/rOQO6YiGSNIM?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: e71757b3-7b69-4cb7-5e95-08de69c2d005 X-MS-Exchange-CrossTenant-AuthSource: IA0PPF9A76BB3A6.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Feb 2026 23:10:57.0136 (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: zOqOl7bHhd2mYJXhafYWs4REEeWHu/ImC1O5h/tNW7SOjhU5xJmwdSd7PnAwjS4z X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB7943 Hi Reinette, On 2/9/2026 6:05 PM, Reinette Chatre wrote: > Hi Babu, > > On 1/21/26 1:12 PM, Babu Moger wrote: >> +static ssize_t rdtgroup_plza_write(struct kernfs_open_file *of, char *buf, >> + size_t nbytes, loff_t off) >> +{ >> + struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3); > > Hardcoding PLZA configuration to the L3 resource is unexpected, especially since > PLZA's impact and configuration on MBA is mentioned a couple of times in this > series and discussions that followed. There also does not seem to be any > "per resource" PLZA capability but instead when system supports PLZA > RDT_RESOURCE_L2, RDT_RESOURCE_L3, and RDT_RESOURCE_MBA are automatically (if > resources are present) set to support it. Yes. That is correct. If system supports PLZA, it applies to all the resources. > >>>From what I understand PLZA enables user space to configure CLOSID and RMID > used in CPL=0 independent from resource. That is, when a user configures > PLZA with this interface all allocation information for all resources in > resource group's schemata applies. > > Since this implementation makes "plza" a per-resource property it makes possible > scenarios where some resources support plza while others do not. From what I > can tell this is not reflected by the schemata file associated with a > "plza" resource group that continues to enable user space to change > allocations of all resources, whether they support plza or not. > > Why was PLZA determined to be a per-resource property? It instead seems to There is no specific reason. Seemed easy to access the property. Will change it. > have larger scope? The cycle introduced in patch #9 where the arch sets > a per-'resctrl fs' resource property and then forces resctrl fs to query > the arch for its own property seems unnecessary. Could this support just > be a global property that resctrl fs can query from the arch? Yes. That seems like a better approach. > >> + struct rdtgroup *rdtgrp, *prgrp; >> + int cpu, ret = 0; >> + bool enable; >> + >> + ret = kstrtobool(buf, &enable); >> + if (ret) >> + return ret; >> + >> + rdtgrp = rdtgroup_kn_lock_live(of->kn); >> + if (!rdtgrp) { >> + rdtgroup_kn_unlock(of->kn); >> + return -ENOENT; >> + } >> + >> + rdt_last_cmd_clear(); >> + >> + if (!r->plza_capable) { >> + rdt_last_cmd_puts("PLZA is not supported in the system\n"); >> + ret = -EINVAL; >> + goto unlock; >> + } >> + >> + if (rdtgrp == &rdtgroup_default) { >> + rdt_last_cmd_puts("Cannot set PLZA on a default group\n"); >> + ret = -EINVAL; >> + goto unlock; >> + } >> + >> + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) { >> + rdt_last_cmd_puts("Resource group is pseudo-locked\n"); >> + ret = -EINVAL; >> + goto unlock; >> + } >> + >> + if (!list_empty(&rdtgrp->mon.crdtgrp_list)) { >> + rdt_last_cmd_puts("Cannot change CTRL_MON group with sub monitor groups\n"); >> + ret = -EINVAL; >> + goto unlock; >> + } > >>>From what I can tell it is still possible to add monitor groups after a > CTRL_MON group is designated "plza". > Good point. I missed it. > If repurposing a CTRL_MON group to operate with different constraints we should > take care how user can still continue to interact with existing files/directories > as a group transitions between plza and non-plza. One option could be to hide files > as needed to prevent user from interacting with them, another option needs to add > extra checks on all the paths that interact with these files and directories. Yes. Adding extra checks seemed good idea. Will do. Thanks Babu