From nobody Fri Oct 10 20:08:34 2025 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (mail-dm6nam11on2088.outbound.protection.outlook.com [40.107.223.88]) (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 C69B525BEFB for ; Fri, 13 Jun 2025 05:18:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.223.88 ARC-Seal: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749791902; cv=fail; b=dGOmzueR22eblsf+CBoYfncoGXT40bYnCHcNiSLXH67EhBxdUA3kqoeRx/4vBQbWf391iy8Fpf9AXu5EnU+iWgCLDkBgfxsLPlStTH3KMyxQ0UftwHRcQq/XBTyn7VYSf+CpXS14bZvM7HQsKwMzXGWArmd3UqL6Ie29sBC77kI= ARC-Message-Signature: i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749791902; c=relaxed/simple; bh=5FX59P+hGvhtviF5FyYCMB91LDG1SdZn1pGieiCxSu0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=YBF+gkjBOU8iLzR04f2p9L5SLxA4ss3KN2qA5Hc7Yh0qvbZ61L3Mg5Jqd47isfA1zFva29kDTrefmnHnyh6iuxY4Inh8/0/1Yano9mxFo5xwXZGRV/GU47DzffY9WicOJZKta9oEuEO3Bo0G9RuzRD/npamBHN1uYKvQxbrTfu4= 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=POHYk/C0; arc=fail smtp.client-ip=40.107.223.88 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="POHYk/C0" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=UnICLM8pbIKkQsTun4r61c5AKZEVLBhZP+toVSo1Y4V00J04iW5URg8vDN9nQscb5PDpmj9MAAqZRDWMoNnDthiKR18WBjgXGm+z12fDz3lygvf3fd9id2UCEwYEN06urhHRZ/DqEjAtp3bh8/IVlLyZuikMd9EdFHZfWnEfQOvYDCRQgx9uOso9LKpemxatrt1Q+YqUZD4zM+uZDxBLfkFlMY6WE/3eZtKJi683z5V4RCcsnO+yXE7ncyHs2qO7ifZ5GdvYRccNbEwk2XGBCxzvPoc3V/SGhEa5/OizxgYlnUap+X2jgGTIn0Zk5GoZeHGlMBPa/Cm4/Wz3MW+G1Q== 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=VblxxYelK6gtjDCRANGjDtmDB34FDt9Lv48gOEPXVjY=; b=EDOBPYPw4oPdJxgAQEsn9V0kBDdtv0C/RvjtN3B+GzbbalVUy0bKhKWEpwtMt4JNje8VPWbHI1gD+FGKSCE+4AuaYOngh+UYMNnI0Yd53vqZHl0bEkp69J1CFoA5ohHwuPIrR8KDIMV9IwjKIuRYBlkHX+IH0ZNJfgfSHdFoLWyqdinoWX8ugk9AWXojDfKvb+r/ABN8s191/V+xoXUPAf+IBf58m2iNftkqUyd9/3BvWBahJ2lI8RmDOl30RnMfcGykFsKTewRdld+88y7mKHHRINqhoJ+KWTQEYZXvkpPki4p7vdvjeI6cGd/aJqpcvX3X/CEQTH2XzYWRmBhqBw== 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=VblxxYelK6gtjDCRANGjDtmDB34FDt9Lv48gOEPXVjY=; b=POHYk/C0ZMr+c5dSJ29brsFrkEVOM5VpuyHi+UAF/TxeJ7W8TMyhwQaqPefyZg30FTcOghJA2XmeooQxw7Jfz8/JXouhZWUH3iRhgz1Cfxwlhn3PS1GlDNRIy1aVskodRZpU4rI8RE1Sio8jAcmerX3vdNEiIYouvd4c2ykZYtEO5zkAClWp+aSRJOqMT8rRfwl+7ZhD2MSnnb7b2A66Auovl+o1abpGIeP1fv9/esI7vxLbTM4nONKmvMlO5OieNFQhAhb/dIjChIXQiU9FfYbfFXfK0mF7S35m2zJCN3zjd8sOEVVSL7T/bBhPxx7sIDnKTijBgG4UlzD2KJWogw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from SN7PR12MB8059.namprd12.prod.outlook.com (2603:10b6:806:32b::7) by DM4PR12MB9071.namprd12.prod.outlook.com (2603:10b6:8:bd::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8835.19; Fri, 13 Jun 2025 05:18:16 +0000 Received: from SN7PR12MB8059.namprd12.prod.outlook.com ([fe80::4ee2:654e:1fe8:4b91]) by SN7PR12MB8059.namprd12.prod.outlook.com ([fe80::4ee2:654e:1fe8:4b91%3]) with mapi id 15.20.8792.034; Fri, 13 Jun 2025 05:18:14 +0000 From: Joel Fernandes To: linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Tejun Heo , David Vernet , Andrea Righi , Changwoo Min Cc: Joel Fernandes Subject: [PATCH v3 09/10] sched/ext: Relinquish DL server reservations when not needed Date: Fri, 13 Jun 2025 01:17:29 -0400 Message-ID: <20250613051734.4023260-10-joelagnelf@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250613051734.4023260-1-joelagnelf@nvidia.com> References: <20250613051734.4023260-1-joelagnelf@nvidia.com> Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BN0PR08CA0029.namprd08.prod.outlook.com (2603:10b6:408:142::15) To SN7PR12MB8059.namprd12.prod.outlook.com (2603:10b6:806:32b::7) 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: SN7PR12MB8059:EE_|DM4PR12MB9071:EE_ X-MS-Office365-Filtering-Correlation-Id: 0cf65943-7a98-4504-f2e2-08ddaa39b287 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|7416014|376014|1800799024|921020; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?04p0ho9eA9I21lAtTFCO12qaADPbrIoRY7BNW1vTh1bKeSNOBpBdMHpuS/Q8?= =?us-ascii?Q?XgkYeyDm/ecIZ58+3ok7X/XchOeiLdDUWTC8rm5I97tw/YQ1V6ssjenmgL4T?= =?us-ascii?Q?clo28KFBVoBpjLviQJFbHLQGvOUYrMrJ3zXzuSUWfLhg0/VEzBeya7c+ngCb?= =?us-ascii?Q?63NorY/eoaT6rLMDjq6zdAvBa27QuN9Ds8xHGBC965klmEZ8Ekwx1QbQfCqr?= =?us-ascii?Q?k7MTPq3cF7fS17nm9PM2+eSnIFjTl48AxpSzZZjHs0/pnufeAnrHGWMeMyZS?= =?us-ascii?Q?vJzuqFB2YRJ8PBiGr98JuA6+sl8yl99gorDzcXGgYXGA4+zfLXox4W6cE8ML?= =?us-ascii?Q?zaZIPqmcQwjo6VmHd3vsOfd3oo+jLVB2wnEWEgugJZaH1CXayMv2uuhbhRh4?= =?us-ascii?Q?2JUwYrONq0Zx5cmPg3Eh6Pog+j09b7helrAo3ZqEihdtYvQ5KsFK3NHmAcnN?= =?us-ascii?Q?bD6cqWJGnGtJ0SWbHsMuSUwvnczLbywyLwChCwZzepyVqoY142AVqAVx6mqc?= =?us-ascii?Q?O+aMQTxc2Z4TqMqKuUkY5h5GwUpSN7ut3fkzPyCQrkoyqSXqBb5w0lLO3Tms?= =?us-ascii?Q?cWBhKV8Ntc4r5AdD4iUodd01qN622EAjU5P0xGO5b0o6LDkEFO2F1yF0cSGd?= =?us-ascii?Q?w5mICVZTf/lBWrTBIt33dXjjH8T5IAf+mXfYtlfkirnFAIKIlFLvDqSY89pa?= =?us-ascii?Q?ZiGobzn8kx3mYo+zV+CdZ2CpMGsFvwNVpjJgjsmpakvf70YlLd6tKS3lRv5I?= =?us-ascii?Q?hzvRBL7PTuxum5cEuL3APLLb6D5EEdnr+x2V+2LJYewBT6JFtRUbcn+vcBeE?= =?us-ascii?Q?v394hEGkMPayyoRc0BBjWREKzwyPnZZ2XK+j7Hp2OuUhk1TGZlEQDrHAN/0I?= =?us-ascii?Q?MJpbBSxw5J9Ws34qW3TNZD9GS7SdyPN7aTAgf93tP6dH/dO48icVX2ZJoSgJ?= =?us-ascii?Q?2ZA9yU8pP4q8gycugpzbbIC2WaCaP2PCSi8A2YyOWSU6vOWjiTjDGK9z6slK?= =?us-ascii?Q?euCAlWjSzNSKuB8cUxFQN3BqNGI2Zr9VIlzM8NVZKQYCvvQPdHDJMEwgvfYS?= =?us-ascii?Q?MqmPHMbxLcxHwjdksCXq68OkmZMo9FBMH5R3ZiWYF3srvc0xK/EkrRkgdzds?= =?us-ascii?Q?SbvFMnDJO+/KPXGfC1krUeCEzjKBpkbbHp4+VAgKlIWvPaJTw+jCT2QUy+Qa?= =?us-ascii?Q?OafOWRJKOzumeNPBnTbnMNYlfEmimAOYWHwMJlts89n9D8jAe+EeTgshJ6L2?= =?us-ascii?Q?8XAN0UKtbdYW+ggecsrm17IaAH7qIcswS9liklpWIWHfN4oJ/hv3VcR3PfCk?= =?us-ascii?Q?qIOqRSFyyfGWUdD20ro8Vz2B1l/M3geUCDeEjVTScdGAeBy8+rV7s5JvdyVY?= =?us-ascii?Q?nZnPh+faBEzi/kHLZMO3ypqi5GFeKrW84l5eX+2YQeTlH4TAeJg4zDgdTBM0?= =?us-ascii?Q?cA1gYhKzAe5XpBXCJJxTKESjPQDMsQlByftW8hmVfUVI2DAOv2ZUSQ=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN7PR12MB8059.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(7416014)(376014)(1800799024)(921020);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?fHIXe7AaUeaukfUUiOJ37slBOYSFR9xTFjXl9i6sjtADaN0p92J0SYT6xhZz?= =?us-ascii?Q?Bnyoc3pSTj+VQw1hLSYxRi3zxeux2OuxGsvmz8cO1pvMe1+4JLRLBcEVCWDk?= =?us-ascii?Q?Pvt/rNHA5mlXDgNLw4xooWBOYRdXtLPkrmQ+bQm+UJO0sb0iM2MNuFsTHxSL?= =?us-ascii?Q?bDx1Z8CLhqfwLylc/ArREIM4OPbWz1OM1NNAMdmtpLbV1FkTLFQmft6omxTG?= =?us-ascii?Q?H/Kv5md9AZvNh2F0Kh2raGkdiLqqzTliyHCwbpVIJZjbG6tOrXa2xX10/EkD?= =?us-ascii?Q?oR5mhqh6ecxUquV61YM3W8tE3yz2FqujrwMqWzwCKDhLTYWwGZsD7BS7lXed?= =?us-ascii?Q?R6B49o/GK/i/3KFIYMHhMVnTQq8+GCkATPUlm/efYb5GkaL07eiV68/RwkGh?= =?us-ascii?Q?ntf1c1JO5UDZcI78WtD6lUaP/CaL5zEhOiF/xaEgjxCPvpvnDuIaI10d9frR?= =?us-ascii?Q?wZQ/iQi2RW/4SshcRQZuq/W4JGdI9UDbbHpJ5sf9BCQex0R4r7V2ba8iB8fu?= =?us-ascii?Q?/Vjb/tTKo+ZPd7CzopaxOMOlojccanHpFbLXFeVuUBhc0iSExedCbDn+HR53?= =?us-ascii?Q?zkG47pP0p0cCHVvk0tgTFm+yXZMa+ZvDTIeZpGA9PA5QnMXRwy15xjvE3zRx?= =?us-ascii?Q?iJILXrF5Xe8lMD0P5nx56ita5Lxt84nUnl92XdKVSAqtyy/FKi3xU1I/XQE9?= =?us-ascii?Q?7NEhiP2QWR0Yl+I3zWM1K9Q5Z34+B8CmAKr5A8yglHU7nbEvhoJ+rEDSXc3D?= =?us-ascii?Q?6cvAKG9kexUxnkRlJuXts9K5rTgDslC/AEmtBCb/Wcd2zf95C3Fnji1veVUp?= =?us-ascii?Q?EFp7wwQKyYECpPosyIedw3eEvYvcsE6VW/wejodO0rLBKIVEpY+ZJ8GtnBW+?= =?us-ascii?Q?Alfx2ufpj/sCWNeCGUnxIkv5KxoBfUD6cT06kEZYOeK7MgUZRtUs+xbTUTQo?= =?us-ascii?Q?BaEYbSpT/bM7YJayNgmDAvcTxHpxWAnzPhIREAc4kEk0hSjMwG3rv52Eb1qx?= =?us-ascii?Q?5ffiSEnJkRuftHjacg8VoZpBSEei+wMY4akuRERwHWXHa9UHB5xMvAaMYugA?= =?us-ascii?Q?Jgpd/J0QhxBQoCL/uX4vov55PrS2tqTGNlVnPXIgl/mF01Acopog46LFOhik?= =?us-ascii?Q?hztcc1cvCzokYpMfAeDrE7eRS/YGIfJSVyXQnThtKELblpPdwtCRKmWHmwuj?= =?us-ascii?Q?U/kgjmM4vA2tKOlr4AwS2gKB8Jjxqvselt1ogITJKIp5XwPu8tlYeeAmWnwc?= =?us-ascii?Q?mN+GIMhQRKyA1+zRUWDPKOZiEG3fJ9ocZJwdYObbPmaslPU1jFKDldrtQjTV?= =?us-ascii?Q?Kbc9q7m2RezV5Ce6lpSFvdzlMZQyAoLUmMFV1asWdvfGeUbbmNuhstqzMqim?= =?us-ascii?Q?gGZ6MiD434xiU5WMlyk5ouceoiFhsOjtinhNE4sZNOfZQ4/ks/8YaBMvqIEy?= =?us-ascii?Q?cH+IwqP5hSUgXy6W+UljwYS7hGL19F9WOBCAU7MmjqD9mzEy0CSe5I6ns2rJ?= =?us-ascii?Q?hD0enlmYgqnLdE4bD5gvs/0QFXd9r6FccSkEYmdXVje/Cf9Hyk5yXIlHE/A8?= =?us-ascii?Q?et+WmeTcyKhMLezp/Ch7o9cW85F6CwV5XJ8/c/H3?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0cf65943-7a98-4504-f2e2-08ddaa39b287 X-MS-Exchange-CrossTenant-AuthSource: SN7PR12MB8059.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2025 05:18:14.2535 (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: toTfhQFxrimg0Ow4LdLJFuefMr17+zEAuk06KvzJUCFJXpV5wHjZfm0/nRnnuLJfPZ8lAiCY2esNFaY6aRUoow== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB9071 Content-Type: text/plain; charset="utf-8" I tested loading a test SCX program and verifying the bandwidth both before and after applying the patch: Without patch: Before loading scx: .dl_bw->total_bw : 1887408 After unloading scx: .dl_bw->total_bw : 3774816 After patch: Before loading scx: .dl_bw->total_bw : 1887408 After unloading scx: .dl_bw->total_bw : 1887408 Signed-off-by: Joel Fernandes --- kernel/sched/deadline.c | 11 ++--------- kernel/sched/ext.c | 44 +++++++++++++++++++++++++++++++++++++---- 2 files changed, 42 insertions(+), 13 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 0e73274d8c31..924dbbfb4b40 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1786,18 +1786,11 @@ int dl_server_remove_params(struct sched_dl_entity = *dl_se) dl_b =3D dl_bw_of(cpu); guard(raw_spinlock)(&dl_b->lock); cpus =3D dl_bw_cpus(cpu); - + if (dl_se->dl_non_contending) + sub_running_bw(dl_se, &rq->dl); sub_rq_bw(dl_se, &rq->dl); __dl_sub(dl_b, dl_se->dl_bw, cpus); =20 - /* - * If server was active and consuming bandwidth, remove it from - * running bandwidth accounting. This should not happen because - * we call this only after the last dl_server_stop(). - */ - if (WARN_ON_ONCE(!dl_se->dl_non_contending)) - sub_running_bw(dl_se, &rq->dl); - /* * Clear all server parameters. This will also clear ->dl_server so * the next dl_server_apply_params() will reconfigure the server. diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 52f98c3944ed..2e77d9971c22 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -4784,13 +4784,28 @@ static void scx_ops_disable_workfn(struct kthread_w= ork *work) scx_task_iter_stop(&sti); percpu_up_write(&scx_fork_rwsem); =20 - /* - * Invalidate all the rq clocks to prevent getting outdated - * rq clocks from a previous scx scheduler. - */ for_each_possible_cpu(cpu) { struct rq *rq =3D cpu_rq(cpu); + struct rq_flags rf; + + /* + * Invalidate all the rq clocks to prevent getting outdated + * rq clocks from a previous scx scheduler. + */ scx_rq_clock_invalidate(rq); + + /* + * We are unloading the sched_ext scheduler, we do not need its + * DL server bandwidth anymore, remove it for all CPUs. Whenever + * the first SCX task is enqueued (when scx is re-loaded), its DL + * server bandwidth will be re-initialized. + */ + rq_lock_irqsave(rq, &rf); + if (dl_server_active(&rq->ext_server)) { + dl_server_stop(&rq->ext_server); + } + dl_server_remove_params(&rq->ext_server); + rq_unlock_irqrestore(rq, &rf); } =20 /* no task is on scx, turn off all the switches and flush in-progress cal= ls */ @@ -5547,6 +5562,27 @@ static int scx_ops_enable(struct sched_ext_ops *ops,= struct bpf_link *link) check_class_changed(task_rq(p), p, old_class, p->prio); } scx_task_iter_stop(&sti); + + if (scx_switching_all) { + for_each_possible_cpu(cpu) { + struct rq *rq =3D cpu_rq(cpu); + struct rq_flags rf; + + /* + * We are switching all fair tasks to the sched_ext scheduler, + * we do not need fair server's DL bandwidth anymore, remove it + * for all CPUs. Whenever the first CFS task is enqueued (when + * scx is unloaded), the fair server's DL bandwidth will be + * re-initialized. + */ + rq_lock_irqsave(rq, &rf); + if (dl_server_active(&rq->fair_server)) + dl_server_stop(&rq->fair_server); + dl_server_remove_params(&rq->fair_server); + rq_unlock_irqrestore(rq, &rf); + } + } + percpu_up_write(&scx_fork_rwsem); =20 scx_ops_bypass(false); --=20 2.34.1