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Tue, 16 Jun 2026 23:42:46 +0000 Message-ID: <10c18df6-d990-4050-bd79-1ca914eee673@intel.com> Date: Tue, 16 Jun 2026 16:42:42 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 09/12] fs/resctrl: Reset kernel-mode binding when its rdtgroup goes away To: Babu Moger , , , , , , , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <280912ae2d2ee068fe5ec94aaf7e6e3f4e1c68b6.1777591497.git.babu.moger@amd.com> From: Reinette Chatre Content-Language: en-US In-Reply-To: <280912ae2d2ee068fe5ec94aaf7e6e3f4e1c68b6.1777591497.git.babu.moger@amd.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MW4PR04CA0302.namprd04.prod.outlook.com (2603:10b6:303:82::7) To SJ2PR11MB8370.namprd11.prod.outlook.com (2603:10b6:a03:540::20) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ2PR11MB8370:EE_|SJ5PPFBC9025319:EE_ X-MS-Office365-Filtering-Correlation-Id: 8029cbea-132c-4278-a0fb-08decc00f7a0 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|23010399003|56012099006|11063799006|5023799004|4143699003|18002099003|22082099003; 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the next read or write of > info/kernel_mode would dereference a stale rdtgroup under rdtgroup_mutex. Please do not word the enabling as bugfixes. > > Add rdtgroup_config_kmode_delete() as the disable counterpart of > rdtgroup_config_kmode(). It clears the kernel-mode binding on the > group's kmode_cpu_mask (or all online CPUs when that mask is empty), > drops the per-group kmode/kmode_cpu_mask bookkeeping, and if > @rdtgrp was the bound, resets resctrl_kcfg to &rdtgroup_default, > BIT(INHERIT_CTRL_AND_MON)) so subsequent sysfs operations resolve > to a live group. Could you please reword these code descriptions to describe why this patch is needed? > > Call it from rdtgroup_rmdir_mon(), rdtgroup_rmdir_ctrl(), and > resctrl_fs_teardown(); each call site is gated on rdtgrp->kmode so > groups that never participated in kernel mode pay nothing. Does this handle the non-default resource groups removed on unmount? (see rmdir_all_sub() called from resctrl_fs_teardown()) (please refer to earlier comments that apply to this patch also) Reinette