From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (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 6DFBA21CFEF for ; Mon, 4 May 2026 16:01:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.14 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777910477; cv=fail; b=cWZ3OO8x7S/6xLzfK1Akw4Tm3FoT5sZcDIu2DI/J5/N36XZlzoNh5Cnmt/vdkbRQdnth0rlLijJV8kKdXrUslX8mHXGBJIlS4TdhxGR72SQ3uV5T3qph1qxbJWuRVtfmslnDJQT/dJqfG4JwtqwWANmOwFN9XPHYAgwI/Au3wSg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777910477; c=relaxed/simple; bh=O0U6IdufSFITPEqqwTAYmt80HpPIOPSuGDHOIM2KHzc=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=QS+gujMls9IU7dL6jVm8HzDk89pv3R2aY5CbpZQO2zcbPAz/fRMm3ggO52kYaYw+xAeM71Xg5MBf6Q6+XXBjNOolK9ZAE44EF2MAVieHUd2qFid95Vkzm3tlvoG4qCx/49EzcRaE5hR5N3+fK9Kjtp6cXn0cYbZ95xp9/+P5oKo= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=XBcabNUc; arc=fail smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="XBcabNUc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777910477; x=1809446477; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=O0U6IdufSFITPEqqwTAYmt80HpPIOPSuGDHOIM2KHzc=; b=XBcabNUcOCYYiIVZATHniGO1JqVUXXImM2LPpNl8fvCyT5sUASBVB54I ZPjaVABUQWxmk2QDxhpoHJlYI4PDR/peXIfEN+sX0QHu2c1bt7wprsXQX GNMmXem/0Ce6xowg2m7kPvxOeHPDz0b6Y1Irc19e6btHo3KcQGKlW0Jx2 xPK89cBPrcahDM8byCw6y1BLIye2FXKd+poy9YM92Iqluau1654tulbce mm2TxROPLg4kNeGbrEpctstL1zDBKqkZPdFPSDygb6x5IeTI7xQZju3S+ G7UJpl8CBQviH2t+Yu7oZt4xGH3P2WGSxxwUHJc96wp9ylLJhZGYbEH/E A==; X-CSE-ConnectionGUID: TihDjaRaQ1+xWHWvUy7YsA== X-CSE-MsgGUID: D10B3rmkQIKg7iUumcAX2g== X-IronPort-AV: E=McAfee;i="6800,10657,11776"; a="82637387" X-IronPort-AV: E=Sophos;i="6.23,215,1770624000"; d="scan'208";a="82637387" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 09:01:16 -0700 X-CSE-ConnectionGUID: /xO7nQ08TheaDjtJDm4FqQ== X-CSE-MsgGUID: JU4JgeCaRC+cTs3jaSREBA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,215,1770624000"; d="scan'208";a="239517106" Received: from orsmsx902.amr.corp.intel.com ([10.22.229.24]) by orviesa003.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 09:01:15 -0700 Received: from ORSMSX902.amr.corp.intel.com (10.22.229.24) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Mon, 4 May 2026 09:01:15 -0700 Received: from ORSEDG901.ED.cps.intel.com (10.7.248.11) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37 via Frontend Transport; Mon, 4 May 2026 09:01:15 -0700 Received: from SJ2PR03CU001.outbound.protection.outlook.com (52.101.43.47) by edgegateway.intel.com (134.134.137.111) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.37; Mon, 4 May 2026 09:01:07 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=iwceyMzndtaPgSOBWxe0NYqh7sNolcMK8NaI2V/C2SHp5zn7ey7D5VQYxCIFU/0VduHEfUShMWtIIeHA2Y6lETheb1/pcL7zNdsWi9n8WwOjoXEHWSmy90pycMZOco+zCQN/h2TmkoyMGBI1H4PVVpmUCYB6ZTL39pSuF5CkYl7ySha+RxbGKSOj7AE/NzuJFuBU9YA0oBa6UdTIFmeq5IcQXt+hXRbh8L3hqeOfKFjMZ/ZtbQyEp4zoNVI8temJoz4rIliJ/DQwJLjCQISfmgY87jWZVVFmhNf4d9b72tMj65uZUhQ90jXui2vwXqUFWgAzwPWHEgfBGtKtrXnPjQ== 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=gEC6dvs/+QgY3z/T9dwfMP8701QpNhZETqkViZn4tAQ=; b=EttlbWfAcplkftLX/zxomxdWk8PofKjKyeCiTuzko4LMqG0DqPSK87T/gfrq7OAuzo2R8HwrVXJJpe5hX9xc0J0BRpfdSHWcWYVW5hjq4TuL3ESGL39xvs9t4w5qTRG3VShRCBRql+q0jq6U9uoc8jEbUfSIcUVVVizXsdvwVIh43k1loqcR5ITyyp3XuDGfkoIzsCBZArwbqqGMwkkEOk33hb4qP1e1mBrDufLrOnvuSJzk16iytOjwXd0+VWi7tLINVYd6P57UkHwGgtNy9sIpyIIm56xqf38SaRmuoZORkddRdsQ3NVnFNggRxov8D4nqisMgGo/qpNbZgi67ag== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) by PH0PR11MB5878.namprd11.prod.outlook.com (2603:10b6:510:14c::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9870.25; Mon, 4 May 2026 16:01:05 +0000 Received: from SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::bfe:4ce1:556:4a9d]) by SJ2PR11MB7573.namprd11.prod.outlook.com ([fe80::bfe:4ce1:556:4a9d%5]) with mapi id 15.20.9870.023; Mon, 4 May 2026 16:01:05 +0000 Message-ID: Date: Mon, 4 May 2026 09:01:02 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 3/7] fs/resctrl: Disallow the software controller when MBM counters are assignable To: Ben Horgan , CC: , , , , , , , , , , , References: <20260428130422.2287302-1-ben.horgan@arm.com> <20260428130422.2287302-4-ben.horgan@arm.com> Content-Language: en-US From: Reinette Chatre In-Reply-To: <20260428130422.2287302-4-ben.horgan@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR03CA0122.namprd03.prod.outlook.com (2603:10b6:303:8c::7) To SJ2PR11MB7573.namprd11.prod.outlook.com (2603:10b6:a03:4d2::10) 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: SJ2PR11MB7573:EE_|PH0PR11MB5878:EE_ X-MS-Office365-Filtering-Correlation-Id: c87c216a-432e-4778-f0f7-08dea9f658dd X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|18002099003|56012099003|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:SJ2PR11MB7573.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?cGdZbDc2OGRjNzUxSjJBN2h6UlZQN0ovRzJlekdHQUcyU1BBQWdWcEJDVXlE?= =?utf-8?B?N3U2ODFvQ0pJc2NaaUhaK1l2UGMzTnVUbWg0aTZwTnU2Q2Vya0Exbjd4SHhF?= =?utf-8?B?c2haU3BaMDhnT0RpQ2x3QXRNamJxZ0UyTjJSYjNpUi9IMDVQalR6dGVyTmFh?= =?utf-8?B?d1FBa3h0NVo2TmxwdEhaK1BLNHd3N2I2c1RKUXVWU2Uyd0dadmw0dEhtbmxP?= =?utf-8?B?dmdvZFc5WGEzRFUzOFdDODJ2ODh5bkdDbDVNdllkMGhvcnNIRzE3ekQ0RVlk?= =?utf-8?B?am96R1lJUlRjM2hrbDk1VGlMakpESzJESDl2bTNZS1NGQTRONi8xRkpTcjVT?= =?utf-8?B?ZEZ5aU5mNENqa1E2NXRpU29ZRmU4bkJVRUw1VVA1eGJlTERoT3JVQlNibXox?= =?utf-8?B?dW5UdFRBcHUvWFMvMjBmck1teXlISytUWkJjRDJtZGU3ZDFvb2FqNWF2clpN?= =?utf-8?B?RmtZQTZ1ZlVuRDhhKzkvM2dQNUcrcGVsM2c0TWFTZllDRHdNekpCVjJUejlF?= =?utf-8?B?ZFp1S1NNcWlWZzNIbHNUaXdyd2tRZmZFYWhWZy9Oa3FnSzJWV2FrbGJvam9r?= =?utf-8?B?SVdDeEp0NDkyazhPUWFIOGhxTExHVEZaa1hsMERwVDNrUThURkNxSEFVNmJB?= =?utf-8?B?bWdnYnd4eU4yZjduOE1iREhSSmtMblJyMmhqZFN2NDZKR0hkN3dLL0xETkJI?= =?utf-8?B?aDRYTngrNU9UM0l3TXlCK1FYZ2xWTjBvejVsUy8vWXJPN2lPQmN1SlFRaDVJ?= =?utf-8?B?OUZ6UWhzcHc4ckgzZ2h0aVBxVTFtM25Wb1VJZ0FzaDZxT1J2THI5bW1aSUIr?= =?utf-8?B?WE1xRDk4MGtNQVpXT21IdExHVExtQ3JLc3pDbjQ2UlhZK0RweUV0NXh1Wmwx?= =?utf-8?B?UE01UEozZStSMm5UYlluMEFubVQyRVJkZnBKNTJEeEthcUlPTXV4VzRVRzlj?= =?utf-8?B?NHpVU3ZTRGtsWHZpNVBYeGlMSFk1UlVvWnRGajlaNGR2VDZ0VGIrcC8zcUdT?= =?utf-8?B?YmJaZzFFYyttR0lDMG4zVFlsd2pLOXowSWlCS0ZHY2NUbS96Q3oyWE9JRkRh?= =?utf-8?B?NjlVUmRFU2JidTNOZFdnR0ZINXphQkI1NzFDQ3ZjZGJxbFNRWi85ZWNVOHRB?= =?utf-8?B?MUMvRHdXM25XbnVWREpzbjBoQXlGVnc1NXc0ZU9xL1VyaEtSSDVMaFlmQ1Iw?= =?utf-8?B?M1V1cVNsRzZNRWFHeWwzbVQ3dG1pNVN4VUN1SGNMbUxRT0pnMjN4Y1dEQ1R0?= =?utf-8?B?RkhXVUNhMFRlT0FKeC9LcVlqY2grWmtWOUpzR1UxR0l3eVZOWU45dnBISVBm?= =?utf-8?B?WEh3S1B6U1d5SThQa0taNUlSNVRtcG1lSjlZa0ZIekw4YlhEQ3AwN3pxdVIy?= =?utf-8?B?YTZ3UVRmSU1XK0V0ajl2bzBOMlRrZ21sSjZYNFdIK2RRY1dnWmlkWDl3Ym5P?= =?utf-8?B?Nmx6a3pFYlI2L0JIQUJLSmR5UWFlalFKWHY1b2IzYU5tTFEzSUNDZXVZZEZi?= =?utf-8?B?Z05uWGRsNGpva1JMbjY3Z3pvRDRoQjg3NkQwZ0k1V0xYdWtneURidDVDdk54?= =?utf-8?B?dE5PZXQvdDRYb3czZ0k5OVIwQkVXWVFBU3FCSzdBTDhWZ1JDcXgzbElNQzI2?= =?utf-8?B?WmlreXlIYUdWVG8raHkxSVlibGJRaE5CWktiYnhUN29CYjJyaGh4emU1REFH?= =?utf-8?B?NldSQW5BZ3VxbWs2TjY2MXpFb2YrUE54a1o5R3kwQzJ2dTFTcFFUZm4wWVB5?= =?utf-8?B?OThwVUwydGMvdlp5SzBPcHI2S3dYektrMHRib3lxNGhuSCs4MEtockZWVExr?= =?utf-8?B?UlBEa1BUS2I3dllkeFBZZmtHVUxPeW12bW4zWmN4OWVvbCtpTStiK3JGMkJj?= =?utf-8?B?aENYb1lFcGJZU2taVHNseDU1NE4rbzZ6bmJOWTY1aDJYcHdFSURkeWpqcVNz?= =?utf-8?B?Q0lCeWduSk4vMFJjRzdlUFlsUUdacUNQeE13V08wQXcvTVIxNlVvV0FwcEVB?= =?utf-8?B?ZW9aVnJudVpKU0V0R2htb1psRnBMVzFDUkdicU9EdkNsaDBsbkNNVmEzOXgr?= =?utf-8?B?dHJTWVVIY0N5cXhFYldINEViWnBtQnpRc2t3UEo5Z2VNYWtkR2RNdXl4M1NZ?= =?utf-8?B?T2FXbnNZcEdORHNzaXJ3UU9oeGJCMFYxY05rL1p2R0UvVHgweStOTWRnRTRW?= =?utf-8?B?cUlOYlZIOFU3VEVETW50YTFYUGpJeEYzTXJzb3VLcmp0NjN4cEgxb2NGallX?= =?utf-8?B?U0g1WjllWHIzL1liVUNLZ0R1b2g1dmN5ZVdVK1lFOFFGWFZKTEVDWGsrcTVB?= =?utf-8?B?VnZMdGNMRjdSMmxZYlJZR0R4ZHU4WG03TnJjaTJ6UjVKQkt0bVlUeFJwenJx?= =?utf-8?Q?/TJd68qSlHHGPYOk=3D?= X-Exchange-RoutingPolicyChecked: S1HPgf7YEvKCmrEQTddaNdGqeFwWO55NQki1atprw1ZIjecqGOFj6hqsypZGnLLV+Z/JZwNMqfk8AOM1iKX0/8/HEB5ym6tL96ZRLHSmbqEnbo/GOgAmAiWPhRtksX3vCB+rotlSRzknqhi9wGAg7xc2p5SDL+dIwqsP+jwZeIlFLD1va30qxQZx3cw/+0h5iqbelsRTMMnznyE4Ou60gNEkTtR/oeGxWtOkXaBKG8MMaZuckduPn5CsGljgV0pQJlKhgUs6lFDUnSTg+QsE9g4sI300Du9AgHLr3xOZA0CYL1+EVr1JM0uuA2u7BWZrdH5lX85LDHIhBGteNxdFlw== X-MS-Exchange-CrossTenant-Network-Message-Id: c87c216a-432e-4778-f0f7-08dea9f658dd X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 May 2026 16:01:05.2349 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 258R7g3z9hlFg0jHzWHZK8DfiVi4i/O+rQG9s00ZlAipVU5oan9K//0Xy9vt0ICrIiSPAR4w93Ca6+bk56nLvxYCSJiPC3wHRezg2+GOlog= X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB5878 X-OriginatorOrg: intel.com Hi Ben, On 4/28/26 6:04 AM, Ben Horgan wrote: > diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c > index b382a348dd79..be84bb210e3a 100644 > --- a/fs/resctrl/rdtgroup.c > +++ b/fs/resctrl/rdtgroup.c > @@ -2530,7 +2530,8 @@ static bool supports_mba_mbps(void) > > return (resctrl_is_mbm_enabled() && > r->alloc_capable && is_mba_linear() && > - r->ctrl_scope == rmbm->mon_scope); > + r->ctrl_scope == rmbm->mon_scope && > + !rmbm->mon.mbm_cntr_assignable); > } For better or worse supports_mba_mbps() has a function description that documents the above tests. Updating the tests but not the accompanying description creates an inconsistency. How about something like below? diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c index 36d21652616e..b456a67b2c24 100644 --- a/fs/resctrl/rdtgroup.c +++ b/fs/resctrl/rdtgroup.c @@ -2536,10 +2536,12 @@ static void mba_sc_domain_destroy(struct rdt_resource *r, } /* - * MBA software controller is supported only if - * MBM is supported and MBA is in linear scale, - * and the MBM monitor scope is the same as MBA - * control scope. + * MBA software controller is supported only if MBM is supported and MBA is in + * linear scale, and the MBM monitor scope is the same as MBA control scope. + * + * Software controller cannot be supported when the MBM counters are assignable. + * There is no guarantee that MBM counters are assigned to the event backing + * the software controller in all monitoring domains of all monitoring groups. */ static bool supports_mba_mbps(void) { > > /* > @@ -2945,7 +2946,7 @@ static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param) > ctx->enable_cdpl2 = true; > return 0; > case Opt_mba_mbps: > - msg = "mba_MBps requires MBM and linear scale MBA at L3 scope"; > + msg = "mba_MBps requires MBM (mbm_event mode not supported) and linear scale MBA at L3 scope"; > if (!supports_mba_mbps()) > return invalfc(fc, msg); > ctx->enable_mba_mbps = true; Reinette