From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH7PR06CU001.outbound.protection.outlook.com (mail-westus3azon11010053.outbound.protection.outlook.com [52.101.201.53]) (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 4F3263EDE6E for ; Thu, 21 May 2026 17:45:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.201.53 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779385536; cv=fail; b=JWFLlVzZoevraAypJvRxO55Ge0AIKenc7/mmnGCOuhNCRKuCpTeSbmVTLEu5N9N/di9nZAER31fZtv0nqoQLFY3YTBsRwSCUg1UZ8iaCUzv2RQnYTvIA18gb9cEO0Zp8Tu2TxI4IjelQMl+nCIflOBqkMdnGbcmJt02O4j10xmg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779385536; c=relaxed/simple; bh=+RzOlF6SOKNvz9L87WHC0dBJ9mvzXSO6pQ2FEreEk1Q=; h=From:To:Cc:Subject:Date:Message-ID:Content-Type:MIME-Version; b=EJTiE86tqFsal1oTxQz9FeFBS25J/HQtCViK9i2OC1XOWtjWlsIfp89rgopUM87dnBExy6nACvf7Lu6pZ220nrvTkRRcfkWC715iylQq72DPPct8XLZr+fbndp6FVLqXP6D+M8oGWtM46eBs+pOE2UN+7dh3ZKHTIxsALBBgMX4= 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=Lln+HLe6; arc=fail smtp.client-ip=52.101.201.53 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="Lln+HLe6" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=afaxwt7qMgqXPSBj3Adq6mGH/Ph+Oa+vuj+OL7c8Tn8oJLM+4rBzp5DNMCkM70ZgVm0nKsW2hPqCE/FNW1hIrWcczsgUi+FM7/CPATyM1IDZBCCNfdF6OQr3pfgrUA6arWskJCLHT/p4pQlrMHpYpsIXBRXJSNzn+emuoJ4wkQwmXKAvKeub4k7Rc8Dk4987oBd28QjBBI2u8ZXA+Zy716FnwbkilZQqCmnDCo5ZJ4OHyyR6NQcPmoIUrYF8cLyI5SPjbssEUybt7lC4zgX22/A91wgI21nN0V3TH/6gCHbyxFjfPPMTWiFyocLZAeb+VZuypVa1FL7WzyudiQDpHg== 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=yoyX6Cw2LOj25W/rn57vnRtKvyy7t0SE6nere1Fjy9Q=; b=LaPvq2/qQocAxpAjE4dvXDogDTI1Ry2C06/mTN77ZX/X774R3bwahoZTiBmYYmUJAIPWrvrMT+bgOCa5E82uLBwY9QAb7ALtB48AV2An0NI8i4tUqsFoQMtIlviATx/KciHwZgc3/W14tVflrFdonZuguIP+2+BY/O+CR2CVUSsWmRYb2Jcp7mzZ1L3G3UDfpcWUCB/y2DEml1urh/XNMoqEP1FpG2UqaQyBTL3r8kGXXL/51+3EnRYORj10G8V/7IVLURuqC+YfVWpKxIjjMfUOZstKNvkLB4WtfY3YEspkN78Hbr8R8f4ZSdLQ2Z4fTNqLQamYqBjPTpc5egESlw== 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=yoyX6Cw2LOj25W/rn57vnRtKvyy7t0SE6nere1Fjy9Q=; b=Lln+HLe6LYEhwvrv2xxQHqVwppCKbgJlvBnfUSZG8ord8AHNuBdvjxNdzpfulpzxpY2hLhjY9nZMLSPMiJYkpr+KTyMHn65PKKbhaUOZQyXkxEKHqEI7CASXKomd+VzFjkHxJURGZhd+LLwy+Y0tU5ODEbrwrKw57PoJAREAT7C0rD67nTv4EM/YEd+FfTkkTM9VhY7o8IjTE/K7pTv+B1+6DGlVUSr3kAOstSrgy3U2Cdo9GaU2XTDyfNZdKxPyZLorkanX9PNBa1aJAGLpZFkFO4TNrOFCLAhy6wMzg1bN9TTNAYr2fAxHuippHeUmO30x1L5w3jFmsh/uxCNQ8w== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM6PR12MB4827.namprd12.prod.outlook.com (2603:10b6:5:1d6::14) by SN7PR12MB8792.namprd12.prod.outlook.com (2603:10b6:806:341::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.48.17; Thu, 21 May 2026 17:45:28 +0000 Received: from DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c]) by DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c%4]) with mapi id 15.21.0048.016; Thu, 21 May 2026 17:45:28 +0000 From: Andrea Righi To: Tejun Heo , David Vernet , Changwoo Min , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Christian Loehle , Phil Auld , Koba Ko , Joel Fernandes , Richard Cheng , Cheng-Yang Chou , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCHSET sched_ext/for-7.2] sched_ext: Auto-manage ext/fair dl_server bandwidth Date: Thu, 21 May 2026 19:33:55 +0200 Message-ID: <20260521174509.1534623-1-arighi@nvidia.com> X-Mailer: git-send-email 2.54.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MI1PEPF000008C7.ITAP293.PROD.OUTLOOK.COM (2603:10a6:298:1::429) To DM6PR12MB4827.namprd12.prod.outlook.com (2603:10b6:5:1d6::14) 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: DM6PR12MB4827:EE_|SN7PR12MB8792:EE_ X-MS-Office365-Filtering-Correlation-Id: 39950318-3796-4cda-ca33-08deb760bf15 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|5023799004|6133799003|11063799006|56012099003|18002099003; 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:DM6PR12MB4827.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(7416014)(1800799024)(5023799004)(6133799003)(11063799006)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?6/XtSceU37TkGGyGRoD3u+np0zF1JQrvVPKZjFarucPBVngPX1flo8rSUiFw?= =?us-ascii?Q?08tBNdOlSL2U7b9NCJT9+RlpJkKL2Y1yu0u0MwmMETeM51zdv5vYgUMfPGOq?= =?us-ascii?Q?r0FKQ1zYP4R2L8HxbEWbSsFSEqs9lxTUGkaDyUnYppOgB149OTw0sGMpr0vw?= =?us-ascii?Q?YF7J2nqsAMhXDPxsiKSeKTkYyzfGlUlRJAsNurlvnSgQ+qxE8LzbChkb2f+Z?= =?us-ascii?Q?jpxjRQY+zDmksP9Bb6kitBN7ebI2M3EdEej1esbw1qCqn+kLdq8q+IlwxXAe?= =?us-ascii?Q?h3HS0xHg7Rw+36Wz38XK7+BUuXHlifMcN6EMOdkD24vHHKJLQkDQr8RGxO++?= =?us-ascii?Q?mUbVexKihH5OKTv7+NHFtKnSstlda2HXQae24QFPUtwJ7m/x7AnIsyoo5p2L?= =?us-ascii?Q?XfYMQhgu+f8/KtXvSOjMFgv6J8POW/fQCSpmyD25dpBq5VwI9m+ndbIGJoZd?= =?us-ascii?Q?jIYoyt7ZlKTV+tNcUw8bA66uFo9VgAne1/6i++WyXiPUKqaLv83PbYxZfvLa?= =?us-ascii?Q?DYOVnj0sKkRXIRxm+yRAbPX4cQbpAki96HvVn4TRm4AIGtJE0maSxEzLKnx2?= =?us-ascii?Q?F/QlivRaKCaN6IRnKJ3H6NJ+qdnMH/wi1Tp7FMVkLhqsHZ1DK5VdjEeTEBMo?= =?us-ascii?Q?JJy27kGmd0DDJ4EF26BFEtirattrOsUDw2OjHMEdT97io7KoSqPSFJJfPIxN?= =?us-ascii?Q?QMqIlso/JbVmz1E+f/RG+1Iy6gySnitH6rjDUSg5kMHNqqWiikSYOhwytE6R?= =?us-ascii?Q?/xcb5dCQ+/9FUYkJSRVQ31uJLHOkT1e5yU2MgOeM87vRCwu8+Zn5BMnXUhO9?= =?us-ascii?Q?rskfyk40U8nlvSgtofAxP8HxjUG/Rd7CLJcRx9j/UcSuBb8zydTV1pHJ6+eK?= =?us-ascii?Q?r5z8uYcJj4R4LMzMspNjZqH/0TTixlGErpkTrrRW3DwpPiIzhvrbPQikBXBK?= =?us-ascii?Q?pNlW6OcJ8NO7E+ZHx1pOh7VXVPXCRV25/lWKq/hPiOMmUv+ud82RQC5D/ngL?= =?us-ascii?Q?LVCNKj31z6jb3GjFCAdlxbR9EPWAxQ1wHJOZHFkoEO/YBa4G4r80+zXdwdcB?= =?us-ascii?Q?DSPB3/HtMx81wAjvgo1lZnyLSXAHlWkFuS24GIidiXz7eh3qI0BwuHbn95pH?= =?us-ascii?Q?dqgsdVlGK19VR6GWrgr4KIQfZuXBPAAsNTDA8xPvQW++zGBaT2Xx+rBZczYI?= =?us-ascii?Q?/3w6TYv6RSxtHT3ohbOQrk8Pj19rUZBSB2PZB2DLPhhnO11WjcHpE8Ndk9JC?= =?us-ascii?Q?5Xzv7XQtpGHJI5RakatDLSvIRcRFQlHIy5S1C9YISno8nyZQ0qi/4kjJKD0A?= =?us-ascii?Q?nw06sPCsBgVxF1+Np6V5/h0nLXJUgQhGEl+ACQPBz89Ctml213y2DroOkYy6?= =?us-ascii?Q?ZkR/nG/KUjKiDFvvdLMV4cPRQmTA4F6JL270yX2i9F/W0HwIFgMY4R8jBRh1?= =?us-ascii?Q?tfd2Dob9VjlnnBHwxr9SkNN+Cv58xm5ETsng1e4cNLQTCsJQFE4AvZsj0rIc?= =?us-ascii?Q?9O+sDecY7yW4OqIrs3o0WXAtFsP0T69W4u5xarXQ844Pf3xWoxFsGIJ5HfTG?= =?us-ascii?Q?6PAALgMUNtFd7iKdnaJjSUL+lV8BFqZPdiofAiFpzIkf/kU+WLiykAIFUuU/?= =?us-ascii?Q?4uiUIzixwQxEn34cTamzpHn3TjWQX5zBtnVGx4IytgwDpKzgGEGA8hx9PeWR?= =?us-ascii?Q?wqnQGspYSQo9TfJIzgQB9TgBpwMML2W5JuZFb/N6UZbbY+eN?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 39950318-3796-4cda-ca33-08deb760bf15 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 May 2026 17:45:28.6474 (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: f2MHvPE9AwYYfKQSKuZ47TKmZNcVwM3edeCfQi4gad+KVgadyqJdcji0LvMUTOhuBMUq5t2Taa6HzGqvg71BlQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8792 Currently, a fixed bandwidth is reserved at boot for both the fair and ext deadline servers, and this reservation remains unchanged unless explicitly modified via debugfs. As a result, both reservations stay accounted in the root domain's deadline bandwidth pool, regardless of whether a BPF scheduler is active. While unused bandwidth can still be reclaimed at runtime by other classes, this static reservation prevents RT from fully utilizing available headroom in situations where either the sched_ext or fair class is guaranteed to be inactive (for example, when no BPF scheduler is loaded, or when sched_ext runs in full mode and replaces fair). As discussed at the VIII OSPM summit in Cambridge [1], a better solution would be to dynamically register and unregister deadline server bandwidth based on the active sched_ext state. This allows the kernel to automatically enable bandwidth accounting only for the scheduling class that is currently active, while disabling it for inactive ones. This patch series implements this automatic register/unregister logic. Moreover, the sched_ext total_bw kselftest is also modified to validate the correct behavior across the different scheduling configurations and ensure that bandwidth accounting follows the expected state transitions. [1] https://retis.santannapisa.it/ospm-summit/ Git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arighi/linux.git dl-server-bw Andrea Righi (2): sched_ext: Auto-register/unregister dl_server reservations selftests/sched_ext: Validate dl_server attach/detach in total_bw test include/linux/sched.h | 6 + kernel/sched/deadline.c | 109 +++++++++++++++-- kernel/sched/ext.c | 43 +++++++ kernel/sched/sched.h | 2 + tools/testing/selftests/sched_ext/total_bw.c | 171 ++++++++++++++++++++++++++- 5 files changed, 323 insertions(+), 8 deletions(-)