From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BN8PR05CU002.outbound.protection.outlook.com (mail-eastus2azon11011058.outbound.protection.outlook.com [52.101.57.58]) (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 8CF8640BCB3 for ; Mon, 13 Jul 2026 16:21:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.57.58 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783959714; cv=fail; b=YcsJNZyJglLM1OjxONhVd4iEJ542wsQcMTJWzWKXNqqbE5kB1i7+5uevprue5MRAHnIvAek2WP5OcDe+pmovpMftFa3Z4K5e7sM+x6hzFSQx5fHMXmRQudyNcvM+mGAGixDbSWxlKr/RAI8HF5+Sd9DLQ4CcILSrH37u+HdFSoc= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783959714; c=relaxed/simple; bh=IsEcQutnXAw+GrQAHzaWdLRO1Gvq1HCd/CHmfp6E5iU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=nooBPwYF2DD/gf4pp6Qs/HVAoeKseZtJRgLS3gZD5fC0AvS1hWGfg2Vjr90rfUULiLP98bB1vaZdZJkWc38NOCyHllcO/bBa3TuQ+eS8fHrDZV2eKt4bK1HAhGjCuUP2WmYzGsblr2euvTiBIFciFTJYm/l+WzwkiYAA9XqTA2k= 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=tQdWzXNs; arc=fail smtp.client-ip=52.101.57.58 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="tQdWzXNs" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=f/YmEi0OLS6pVyUnqERxE0RqiG+Wh2jGBcwu3ToBxUoGPV2AErH1Ybn32skn/w7FzKneAQMxZbVxL8AC543Gwna3kHQ+OCHutSa8Fx69VjtG5M/o7zQB/fCf0Xj71MXVeW43n4C6kqs6YrjWNOFbopj0jUrZiW1UfJcgN6Xq8g79BwOUjEHmw+ujvycKWBVoeeOulcacMCfNp5GYTGIOrW7mourCevGPpvjQawq1F964Fuu5pF13OchfPLPTH4LHxsuKWSLdhNI+eWY1omQOUlorQXTtQTNKKCkogg42TBNkTQUol9dSGKHOKsLTnUgAhdO+v9p9v+VuUdE0gZza/A== 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=f/uxrNPVQfo17Ms/itS2Ocq638YFe66+fPUAZgTAfN0=; b=k2tbCwy0epH6eB0SCtZkGKe9bGb40GeLucGRU/RFVs//lw9eeWhFIhtYbgtYDxqd0Z3iDzjXeeJ4Yrvoh+gDD5S8d16el8fvznWBIZDxRbr40z7KbuomYZmSDbeIOBbtR3KVUw99ru/eZ4eaSAEnas0COdGGrzhnxvOu7ioeUCUr2brw3puvrVBsXPg2QfXerR8sBJ+fgFQQ6t8wO8JedF2/GVbv7CZKomE5Lw3ihWu5RLAwkx4fyMD4a+QKQ7YOxeB0BWjn0Zy+RzeAOEb483U5zlupT4kPHgUGbgA/5AkCVUEbvmzQw4v34e69Z+ddhxZglqW/W7J6kAs8oVR9FQ== 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=f/uxrNPVQfo17Ms/itS2Ocq638YFe66+fPUAZgTAfN0=; b=tQdWzXNsqbcz3H3XqZk5BSKe58NOUhWNmIcVBGe1sWInV19dbaRIcVZ18WVh/isJKtb1/XNN9gHItov8S/f+4GRDvXsk0rjhbxcW3R2UlqjAH586qm9ou+I07Yjh0/HGY9JKAK+/JO3gIjYQABVlSmW5Ktd5u8S78fGYXgNQt4fM8ym6GppGFNhq4Qt2Xs4CYTJkjXZK/EE3yMqhZwGHpW6cEjSGrKLR5XnMgqBBuy2yIM38wwiP0vYRHTaAixdpumBqtE8HUkGMNv6b7lTRcPz5SxUDGy3MIl6zUWwuDMAcv6XNjOtSe3ppiXdbveG2hiH6Gpq1iZbedN6eXdRk+Q== 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 BL1PR12MB5755.namprd12.prod.outlook.com (2603:10b6:208:392::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.181.11; Mon, 13 Jul 2026 16:21:46 +0000 Received: from DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c]) by DM6PR12MB4827.namprd12.prod.outlook.com ([fe80::6261:3040:864b:159c%5]) with mapi id 15.21.0202.014; Mon, 13 Jul 2026 16:21:46 +0000 From: Andrea Righi To: Tejun Heo , David Vernet , Changwoo Min , John Stultz Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Christian Loehle , David Dai , Koba Ko , Aiqun Yu , Shuah Khan , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 03/10] sched_ext: Fix ops.running/stopping() pairing for proxy-exec donors Date: Mon, 13 Jul 2026 18:17:03 +0200 Message-ID: <20260713162112.26785-4-arighi@nvidia.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260713162112.26785-1-arighi@nvidia.com> References: <20260713162112.26785-1-arighi@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MI1P293CA0004.ITAP293.PROD.OUTLOOK.COM (2603:10a6:290:2::13) 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_|BL1PR12MB5755:EE_ X-MS-Office365-Filtering-Correlation-Id: dbcad0e5-a745-4291-c4ce-08dee0fad566 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|23010399003|366016|1800799024|22082099003|18002099003|11063799006|5023799004|56012099006|6133799003; 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)(376014)(7416014)(23010399003)(366016)(1800799024)(22082099003)(18002099003)(11063799006)(5023799004)(56012099006)(6133799003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?HBuYzA1oLrYdMI/gPtznuGAL8O8CG8MkrYWxt1a/qHTVLQgP0S/SaHdXUZXj?= =?us-ascii?Q?Y77+YGwDb8vPuNTkyyCuibBtqzeX6A2NsmtTuYl49ZOh9OQ57FONC8HShpg1?= =?us-ascii?Q?691CZv8BKMEXlK1VUOneHm+AQYdtMFTS/UyU37gRR8ggyVEdMnm3q7AmyfiS?= =?us-ascii?Q?fHvLTlEDpltqkcUobOci9XmZkyfecQ8FfuBHHPQrhl8oU+uPS8Lim4fu/T/R?= =?us-ascii?Q?btfiKRdw0DCSnxqno1mKfdQyw4OC8TclDhBMlSeXTAkoAFF5MBXRN/jKqj06?= =?us-ascii?Q?drYOAIg11nrpNBBQ1YNF1nvteXXwWa40W9Lw8zRnw9ns8gF/SaVYXSdlk65j?= =?us-ascii?Q?4LZJg6hbaQmoqkDUv4SzboUbAEq/9MGn8Q7sWq5P/J21eQMTJSq1XkUd7fbW?= =?us-ascii?Q?NEej+2UFfzL51tYozpoX3vMl9b9anAdjoRCxac9+vfV4hY0Y1bBqTLyL+oNA?= =?us-ascii?Q?sAILh5MxPI5pkP5cce0bN2PGEBQ7V42SiIbgwu/W/kCKIwPEkXzJ5vGPVhRk?= =?us-ascii?Q?e09r5OkmQqcHKr3lJBAcb7lwIJK4hiuc9nhIyWqGgVC7jDikWrW1lWHN9YlE?= =?us-ascii?Q?bejJenhz0wPe0PLfmW66MnalCxYBgJewxRzElCGBhWuCNwbR+eXP/La/5yyS?= =?us-ascii?Q?xwTs255mpKXPYHmYjR81J498TPRxRkEzCcCkgq6TayOd7k+tI1hCViqrbeKa?= =?us-ascii?Q?YIZGjcuWwJlOiI0gDCzHER3JKjlHZd35abKdNRcGqr40lc2aD86I5vql4G79?= =?us-ascii?Q?8WqHjiEHBbCZb7XXsumQGIc10UTXz4CRfL6nFGrO9UxRSNVSSDIGiJ9IZweQ?= =?us-ascii?Q?3w1mAm+TsZuOM4h9fMY8z7515Wz+m5zomdgoCLlRon6VcWFnRoTDT2tJW76t?= =?us-ascii?Q?qw2K5pBtcQ56XWceCse/FdrSagtGFwsCxD38r9LI2A7awzd8pDDmNtQedBeI?= =?us-ascii?Q?jLP+RfoG2SH9z9FyK1i5Gkj0ikOoR50kSRyyNJVYFs4/K8B+bklbb7aspmoC?= =?us-ascii?Q?LDKtDBQuWSDdquLWo9VJO3o1LYNO9+abLAWKNRaTEyBWwrWXlu/LhcFnNa43?= =?us-ascii?Q?LXpNGUrjt3HQ33XtSUuRt8PAQq74HvZbUtwitZbFkzcQ8xmj9j7yjBaWfXCL?= =?us-ascii?Q?hjeyjd64t+IxS+JuQpW58M4tX9kmUjx6rQr4xyKRvn9Uf0++34TVn2FxSeEn?= =?us-ascii?Q?FrgmJryoIWTr5FQdG1PfenPQWr6JW5tuJC/BOV1a5FQCvMP1WTVXY9T7f1+H?= =?us-ascii?Q?ELQwWCVppROrWcVEWAdlTMjQMWjI2caUvfnO4z4Cj/OgnheVxUVH7IrTHkNI?= =?us-ascii?Q?mOl0f93XOFxilXGSaV2SV40Sb0mkF70gF5yqhR1u5bkwhKBtRQ/hmvMM+iGq?= =?us-ascii?Q?hwC2tr0I6GAqfiIW0njKThZ2HrjJzoeY5157tHQP0vSNFODoaDrOsR6wBodN?= =?us-ascii?Q?cZva0/QSvPaxcGnqoGqU6x6MVdCVXyjpDSqlGIzi19aRH+mapV5fjY+VN+Le?= =?us-ascii?Q?zkglIOd6wuExM1q5o3nQDsnmZPBtha3g2oY3gxsEQEQlzkvUpfKOqN8w9tiQ?= =?us-ascii?Q?3vlshROH/cHMm5wZv1V9QPYXMs12yvxHCXKwwvQ/+UqOEIGLCqSbFXrMxI2i?= =?us-ascii?Q?rkASS1QzzrdIaDOX2s6f7OVZ7UpEwBdEQIQ7p4peftWFG74OXuaRk0otGjfG?= =?us-ascii?Q?1q3ycpx3RL+Os0pySA4QZToCIhqZfKqK8jvvpVQKObLduqMsimy+FkUdTfGy?= =?us-ascii?Q?OAPkv4wydg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: dbcad0e5-a745-4291-c4ce-08dee0fad566 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jul 2026 16:21:46.1617 (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: i9crngDuCrB87B9UDDIo4Or/BiiHTGCMf5YemHwcIvfar5CMyTXpMnw93tXHPAt8medkGffEZ0EO6MqYnwYySg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5755 With proxy-exec, pick_next_task() can return a task with p->is_blocked set (a proxy donor). put_prev_set_next_task() then calls set_next_task_scx() on this "ghost" task even though the task only provides scheduling context and never actually runs. Calling ops.running() for such a donor produces a spurious running event. Simply suppressing ops.running() is not sufficient because the following put_prev_task_scx() would still invoke ops.stopping(), resulting in an unpaired stopping event. Introduce SCX_TASK_RUN_TRACKED to track whether a task entered an ops.running()/stopping() session. Set and clear the flag independently of ops.running() and ops.stopping(), as the callbacks are independently optional. Invoke ops.running() only for non-blocked tasks and invoke ops.stopping() only after entering a tracked session. This keeps the callbacks paired for proxy donors while preserving stopping notifications for schedulers which only implement ops.stopping(). This is a preparatory change for enabling proxy execution together with sched_ext. The explicit running-state tracking is also required by later donor-based accounting: it prevents an EXT owner executing for a non-EXT donor from being treated as the active EXT scheduling context when it is dequeued. Signed-off-by: Andrea Righi --- include/linux/sched/ext.h | 2 ++ kernel/sched/ext/ext.c | 33 +++++++++++++++++++++++++-------- 2 files changed, 27 insertions(+), 8 deletions(-) diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index 75cb8b119fb79..eebb7e10086a3 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -102,6 +102,8 @@ enum scx_ent_flags { SCX_TASK_SUB_INIT = 1 << 4, /* task being initialized for a sub sched */ SCX_TASK_IMMED = 1 << 5, /* task is on local DSQ with %SCX_ENQ_IMMED */ + SCX_TASK_RUN_TRACKED = 1 << 6, /* task is in an ops.running()/stopping() session */ + /* * Bits 8 to 10 are used to carry task state: * diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 8c527fa14a15f..2bd7d6efa1f2f 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -2010,9 +2010,13 @@ static bool dequeue_task_scx(struct rq *rq, struct task_struct *p, int core_deq_ * information meaningful to the BPF scheduler and can be suppressed by * skipping the callbacks if the task is !QUEUED. */ - if (SCX_HAS_OP(sch, stopping) && task_current(rq, p)) { - update_curr_scx(rq); - SCX_CALL_OP_TASK(sch, stopping, rq, p, false); + if (task_current(rq, p) && + (p->scx.flags & SCX_TASK_RUN_TRACKED)) { + if (SCX_HAS_OP(sch, stopping)) { + update_curr_scx(rq); + SCX_CALL_OP_TASK(sch, stopping, rq, p, false); + } + p->scx.flags &= ~SCX_TASK_RUN_TRACKED; } if (SCX_HAS_OP(sch, quiescent) && !task_on_rq_migrating(p)) @@ -2707,9 +2711,17 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first) p->se.exec_start = rq_clock_task(rq); - /* see dequeue_task_scx() on why we skip when !QUEUED */ - if (SCX_HAS_OP(sch, running) && (p->scx.flags & SCX_TASK_QUEUED)) - SCX_CALL_OP_TASK(sch, running, rq, p); + /* + * See dequeue_task_scx() for why we skip when !QUEUED. A blocked proxy + * donor is also skipped because it provides scheduling context but never + * runs itself. + */ + if ((p->scx.flags & SCX_TASK_QUEUED) && !p->is_blocked) { + if (SCX_HAS_OP(sch, running)) + SCX_CALL_OP_TASK(sch, running, rq, p); + + p->scx.flags |= SCX_TASK_RUN_TRACKED; + } clr_task_runnable(p, true); @@ -2812,8 +2824,13 @@ static void put_prev_task_scx(struct rq *rq, struct task_struct *p, update_curr_scx(rq); /* see dequeue_task_scx() on why we skip when !QUEUED */ - if (SCX_HAS_OP(sch, stopping) && (p->scx.flags & SCX_TASK_QUEUED)) - SCX_CALL_OP_TASK(sch, stopping, rq, p, true); + if ((p->scx.flags & SCX_TASK_QUEUED) && + (p->scx.flags & SCX_TASK_RUN_TRACKED)) { + if (SCX_HAS_OP(sch, stopping)) + SCX_CALL_OP_TASK(sch, stopping, rq, p, true); + + p->scx.flags &= ~SCX_TASK_RUN_TRACKED; + } if (p->scx.flags & SCX_TASK_QUEUED) { set_task_runnable(rq, p); -- 2.55.0