From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SA9PR02CU001.outbound.protection.outlook.com (mail-southcentralusazon11013065.outbound.protection.outlook.com [40.93.196.65]) (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 F371D2EC0A1 for ; Sat, 21 Mar 2026 23:26:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.196.65 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774135617; cv=fail; b=IJ5NSnTZ9t4RPyFDBm1DvMuOhhxHm6lKigX53GwDfDyhiHoPIa6nFUTe4bgTt/g2PWs+wnYnEr0T8Z9l+6MCqQ6Thoptowg8KcRSt+ukbAweghhnzPD5W6/tdjh5TjBcy10nTxZGznLv9Pd6KAc/rUSwxvqHjsdSA7HI9u5qRjg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774135617; c=relaxed/simple; bh=poDqAyB5Zufov++qtst0vE1mA9sSMJ/Pnn1FktH+8LA=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=IIbgpcL61k2lBHHV8CChGuL9b1BDHfH0gAhg4LDiwmYNrRx0obGp2APLodDckoo5Ts2xBR9ozLSbB5E87KkR2Ql/fDGqwnHoOXHo05QoN8qlM2QxNQvN6FrvKfQ0NulvhofVWkx0usoc+/TheeUIFRo9DG8CpNXs7PHwP+OVNgM= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=N1YMzuou; arc=fail smtp.client-ip=40.93.196.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="N1YMzuou" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=P1Y4p42+XVskDCCvySGSB1RiDKzvp8QRJuux50+NZqv69oYBf3LivWGle8mkNOcmvFCCOB0zMBon/YmmCqPmHCvkcUmCsj16k737dWIRn/UMJJhbQYvYA5C0Rhgo8u3Gf0ZDfviPptqfZcxSZzho8iLs3rpJdeJCnJ3lnDBqFtocoKK1vZA5ALhRLgY5EYi8dsroIqONvhpxtJx2CTtBpVZJ2Vi9z+rOt+tXlcx/K9x9LjQXOaAh8rE2lTJ1Qh22hoocrfIppvM+MfOzROnVk1E6Yubdux0l0uoFoKrXzdiLIK0dq8SdS7XCHUFnItjsVV8xi4YR4IVZSLqrVImunw== 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=WKGkbnBDEjjUBdEWA6yTxquu0nCByb0aIKe/x1tdjpE=; b=wqx3FcXpecfVNN2+n4NNHsRarzFMxn1qzCHL6Rorvf9APhSSXfz7gKlCV/Gwkfa+6EPmPe6m7n0VMAz3ZUpnjq3E02lzenf0W47WbKJeDOR1L7qHtLVEzra4PZwo0IhjO3cW5oH9m9+5y7B9mfFwrSw9oSrMslitg0pzGJh9C33V6MMFVS9Z1DwfZtUm3tXViqHB0mEBHLT4Wew/PQMimqH5PjgghnQHNqxG+mYPnrEHlwYJtY9fC9wRwq9PNI6wBuXMoaRUqCuEnUSzqOPWOyddLnLQGq90WeEHthGPG+aY9SH3vLjHQ74wo944m9niYyQA0JlQt8V2YxFEu9OXlA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=WKGkbnBDEjjUBdEWA6yTxquu0nCByb0aIKe/x1tdjpE=; b=N1YMzuou2IGP2cNzTvOTPczBl7TBp+3zACsL2tn9SDLhz0HAIzTvCQBcH7vTVK1JTw5V2evSPx+s6Ef5vG315Pef968ccGItYRZr2eSg8qOKouGa2bRChPgjreNe453GAMC9w+cdsQgLO2M0SkCiMXsjeVgiHH2Wui5FeyPJwP3GURj3MZUyVoiCvEjAG8eBDY4AgdrWs/NaYccfrkw22AF9IUex07sO+pVTpeVnIkP+iqsrKjFNZiB1ymtR0WJlQB/WDseJdTRvH4wA0QPnKCC3QMkuYT9LH1f7sojyn69nrGFwHchXvkXYeoDUMxYvVRV3tWtYVmqPEBX7uVICIg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by PH8PR12MB7112.namprd12.prod.outlook.com (2603:10b6:510:22c::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9745.15; Sat, 21 Mar 2026 23:26:52 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528%5]) with mapi id 15.20.9745.012; Sat, 21 Mar 2026 23:26:52 +0000 Date: Sun, 22 Mar 2026 00:26:49 +0100 From: Andrea Righi To: Tejun Heo Cc: Cheng-Yang Chou , sched-ext@lists.linux.dev, David Vernet , Changwoo Min , Ching-Chun Huang , Chia-Ping Tsai , kernel test robot , Emil Tsalapatis , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched_ext: Fix build errors and unused label warning in non-cgroup configs Message-ID: References: <20260321070605.691776-1-yphbchou0911@gmail.com> <49aeada41a0e78e9673f053806321df3@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49aeada41a0e78e9673f053806321df3@kernel.org> X-ClientProxiedBy: MI0P293CA0006.ITAP293.PROD.OUTLOOK.COM (2603:10a6:290:44::17) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) 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: LV8PR12MB9620:EE_|PH8PR12MB7112:EE_ X-MS-Office365-Filtering-Correlation-Id: df22f1d3-b443-4b03-2c44-08de87a15516 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|7416014|1800799024|18002099003|22082099003|56012099003; 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:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(7416014)(1800799024)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?KltuCZi8VBOOTetMq+fpb+e36HTn8GMpfxtYQfdzikgVi2P4GI6JGXeP2jkW?= =?us-ascii?Q?Q5/elOzAQYTPuMCJf6pevAvlrIcYkg+3cpw/ZgXyWLfeeH0i2nykREDzYKQG?= =?us-ascii?Q?cweo2V983+rbZIS8b5IPQgiI5fC8PxZhZVt85w29+ryopoYYCZeXg9aNYY2U?= =?us-ascii?Q?CMrZ8PnqVFtXYzi/ild0O6O++jESafGFokApBMYWQ69D8AtrD7oa0/EM4FNA?= =?us-ascii?Q?HMxiblMogUjO45d3Z0bdxXvnM0ttFzIRZi733HFhT5w6oaQESSrFETDw0i9+?= =?us-ascii?Q?KPCkC8vtbzNPl4Y3QOMiJOERF2vgli23WzWwRPZVC5GACeygsqU9b6EccgyP?= =?us-ascii?Q?5fIvVMqzq9pNR9U8w2t3Lruc104lFUiwUeaSbS9litSpA3/xoCALt2i89ou4?= =?us-ascii?Q?3kFmDeRBCPYbDTHjnYL4pEZaTLGmydy+dr7tA2Km6ueTo3kYDi3nhO5bMA2Q?= =?us-ascii?Q?MGJCCx4Rm802aMt2FKEdLUcd9ciEmv3qKoJJiw8TQGkogEDjN05SW7A3RDb8?= =?us-ascii?Q?2A0lx5S2BnmgKK8bRjdDAtIytiupS50tsEwjg3LQm1UPe3aLkUzb3HzKo8q5?= =?us-ascii?Q?mLwWdA1zFVov6XU+QvFc7zffqEk6L+ulCyeMEJI06cN4SmYfCPYcZpTF/Np5?= =?us-ascii?Q?ya4dJSEXf3T8Gt7dt/xeMKAQhKpn6MJyJeox+kUWPYEPrbuniFdr/NeC3QqZ?= =?us-ascii?Q?F9KPJEaWOJrjOv1tbrcJuGk5OQFVWQ3ZNIqgKFOu+MdVw9GxEarzoKj639/E?= =?us-ascii?Q?7xVuYXeUIiDD8yqqNPMOwIq//g4V80A+AJgYxG3ILNHZHRtEYrfBMpY+vNZs?= =?us-ascii?Q?1XB0JQ5fDKbijF3TsRSKrd+Zae9+aBbQdbu3IQQ1mPrDF5QuOTev+MOQpMG3?= =?us-ascii?Q?13sVMMBkl5CxWpn8jeEl8+VGoyyd4jpgd8k1dj0qaEdTE6mDmRkXI+mJhPF4?= =?us-ascii?Q?kKxk1ZFriuFyE80Cw5z2jpkzYblCSx0o8SZuUsYHg7ANoAEJBQzTD+DYdnlj?= =?us-ascii?Q?2Q3pd0FAgJfsMrpnQAHbu8CHN0AWGEYAmfla4kIID5tr64C63wHT2jc+Nwpa?= =?us-ascii?Q?s5j1gi1N+KnLzw8ZDynntOKzd3herVyxcePrg4A8sOmzoBKvGKzs5QlW47ZO?= =?us-ascii?Q?3b19HSbW4E+JAMd6D3tP2kSs0meXNMz5mAcSmktxflG5ZfaN/q1VbnaGN+CX?= =?us-ascii?Q?IDRH2GbF1GWCXk3vjmXHAptzrecPIiMIDE0+d3/nxxGeFRQkTAY15od6ZZb7?= =?us-ascii?Q?JJAphkBm0o1UHbnv3Fwv2LJz9fMNLn0uCh2BdI0ZPbyEIPFFkg9F4liEmQie?= =?us-ascii?Q?xKFi4hg6pwHwX0SqRIdVkoAuPBrA95HnhWAfgPshbScBoG6sA+A1qPKH0mju?= =?us-ascii?Q?C3abciJNNa0hCGQ/KNPA1HGCLRyYc9ZcjCTkhCpXYE7pPS5C9Rapvy+PhcLI?= =?us-ascii?Q?B+y1zGdA2ZB8MVmiQ7BZRNf+ObnCH+oCowNNrXYSILXGOQByR22kVh39fYqE?= =?us-ascii?Q?1VxtoQ6fVqoEdC0bYLrv9GpCSn1pnA2JoyMer5jdiFPfbOfHabaS7B++W7NT?= =?us-ascii?Q?u85DlLOE5JyeMMlohS64vRlPdTo3L3D81isJOUPxf+w6Rj6t8uySaBSPMIwK?= =?us-ascii?Q?enqxGyrDK4fHumbk+NXWY8IufcIJH15Sae0IVqmUZ9+Tm+RlQkbZCzhmDLhy?= =?us-ascii?Q?7fA7V/4Oq5gS8umpK/anFWrjTwYGoMN8zOB3FERnJBbFDGudCcxuWYlWB5GM?= =?us-ascii?Q?IBA/RXNbhw=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: df22f1d3-b443-4b03-2c44-08de87a15516 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Mar 2026 23:26:52.1894 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: MPugsWZVi9gqo3VCibvRAiyQrZl/2Tqko6bO4WqPCUJ76DDczJIjk8AeX69Sc4vqWrZvZVt3fqXxqBAsoJUzXg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB7112 Hi, On Sat, Mar 21, 2026 at 09:10:03AM -1000, Tejun Heo wrote: > Hello, > > On Sat, Mar 21, 2026 at 03:35:20PM +0100, Andrea Righi wrote: > > This looks like a false positive, the kernel test robot likely tested > > with a manually crafted config, so I think we shouldn't apply this > > patch. > > It's not a false positive. CONFIG_SCHED_CLASS_EXT doesn't depend on > CONFIG_CGROUPS in Kconfig, so SCHED_CLASS_EXT=y with CGROUPS=n is a > valid config. I reproduced the build failure using the bot's config. > > The issue is that CONFIG_EXT_SUB_SCHED is def_bool y depending only on > SCHED_CLASS_EXT, so it's always on. But EXT_SUB_SCHED fundamentally > needs cgroups (cgroup_path, cgroup_get, cgroup_put, cgroup_id, etc.), > so the missing dependency is there. Ah you guys are right! I was assuming that you can't have CONFIG_SCHED_CLASS_EXT=y and CONFIG_CGROUPS=n, but that's just wrong. So ignore my comment and sorry for the noise. > > Cheng-Yang, can you send a v2 with the following approach? > > 1. Add CGROUPS dependency to EXT_SUB_SCHED in init/Kconfig: > > config EXT_SUB_SCHED > def_bool y > - depends on SCHED_CLASS_EXT > + depends on SCHED_CLASS_EXT && CGROUPS > > 2. Guard err_stop_helper with #ifdef CONFIG_EXT_SUB_SCHED (only > jumped to from within CONFIG_EXT_SUB_SCHED code): > > +#ifdef CONFIG_EXT_SUB_SCHED > err_stop_helper: > kthread_destroy_worker(sch->helper); > +#endif > err_free_pcpu: > > 3. Guard cgroup_get/cgroup_put in common paths with the existing > CONFIG_EXT_GROUP_SCHED || CONFIG_EXT_SUB_SCHED pattern (matching > the root_cgroup() / sch_cgroup() stubs): > > err_put_cgrp: > +#if defined(CONFIG_EXT_GROUP_SCHED) || defined(CONFIG_EXT_SUB_SCHED) > cgroup_put(cgrp); > +#endif > > and: > > +#if defined(CONFIG_EXT_GROUP_SCHED) || defined(CONFIG_EXT_SUB_SCHED) > cgroup_get(cgrp); > +#endif > sch = scx_alloc_and_add_sched(ops, cgrp, NULL); > > I verified this builds clean with both CGROUPS=y and CGROUPS=n. And this looks good also on my side. Thanks, -Andrea