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Thu, 24 Sep 2026 15:27:32 +0000 Message-ID: <26f421b4-670a-4045-bc06-e801df65cfa8@intel.com> Date: Thu, 24 Sep 2026 08:27:30 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 07/25] x86/resctrl: Update special case for Intel Haswell enumeration To: Tony Luck , Fenghua Yu , "Maciej Wieczor-Retman" , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu , David E Box , CC: Christoph Hellwig , , References: <20260916231320.14502-1-tony.luck@intel.com> <20260916231320.14502-8-tony.luck@intel.com> Content-Language: en-US From: Reinette Chatre In-Reply-To: <20260916231320.14502-8-tony.luck@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR03CA0264.namprd03.prod.outlook.com (2603:10b6:303:b4::29) To SJ2PR11MB8370.namprd11.prod.outlook.com (2603:10b6:a03:540::20) 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: SJ2PR11MB8370:EE_|MW3PR11MB4569:EE_ X-MS-Office365-Filtering-Correlation-Id: bb126bed-4ce9-4fe0-1230-08df1a505a07 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|23010399003|10067099003|56012099006|5023799004|11063799006|4143699003|3023799007|18002099003|22082099003|921020; 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There is a quirk to check for support > and provide hard-coded parameters. This quirk sets rdt_alloc_capable > to indicate to get_rdt_alloc_resources() that normal enumeration is > not needed. > > Drop setting of rdt_alloc_capable in cache_alloc_hsw_probe() in > preparation for removal of this global variable. The changelog just states "Drop setting of rdt_alloc_capable" without any explanation *why* it is ok to do so. Consider something like this draft: Certain Intel Haswell CPUs support resctrl L3 cache allocation but do not enumerate the feature. A quirk probes for support and provides hard-coded parameters. The quirk sets both the global rdt_alloc_capable and the resource specific rdt_resource::alloc_capable, only the global is used to signal that normal enumeration can be skipped. The global rdt_alloc_capable is redundant since rdt_resource::alloc_capable already carries the same information. Stop setting rdt_alloc_capable in the quirk and rely on the resource specific flag to prepare for removal of this global variable. No functional change intended. > > Signed-off-by: Tony Luck > --- Patch looks good to me. Reinette