From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BN8PR05CU002.outbound.protection.outlook.com (mail-eastus2azon11011040.outbound.protection.outlook.com [52.101.57.40]) (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 1DADE3B101C for ; Sun, 16 Aug 2026 17:38:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.57.40 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786901891; cv=fail; b=YBNPsaHnwRAR4Q1qFcRyq7SR+TNtcCGSMsgDqUUg/wnmoIvFtb/KEDWGJimPt9bomr9qleYUIET7mRlaCsiRFgaQLUbKy7XJ9AhT31HvOCxsdqYuagr1fAf/ms+j9IvgW3mmNJ4+Wd80PNoPxzsko2w5vQ4DjXBL1uKcKI/PehQ= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786901891; c=relaxed/simple; bh=WYIM1Aqx0ZLCkuYhr+VKeo2BvR0k0kjJ2LWsewBh9bM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=KP9gyYa7mYp1dHnO9tvfpzDCqz/9RNpxgWYfd7bM2Q+qr+FKG6E6zOCmCwtEgxHYviwNnTsdYP39Y+XhuJQQk5WakBT4BM1vSrwcu47yXVbf99Dm3fCSBItonh5D7rT49n2Q+9e2y7UoifIBVcbJlPjlqxdcQ/ZJkko3SqWbly4= 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=TWRo8Pq4; arc=fail smtp.client-ip=52.101.57.40 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="TWRo8Pq4" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=AH3Dv0FxKrVPaoYmgNTtIL+8dZ96ylnVoNSJb8lhSvCajNsYH7uLLl3nhOBg/13hB0yyWb88MejoPDhdtbJPqMJo5Z4Fa+0s4obn6yeghOT+WzDH7tkT3GIh7cNnE/+HNoLim5b8zWNFw6LE5p4XyBojtaLoiiABeXHClAxKznRJJc7oUmovBgwnbcfI9uNwLbhdR7dlxqvIGQy+w9NS+nlNCgfOZHnHDNuwK4AyhXnN087C+/wHSomMXe0R9OF9o+95vXGLp6GOeAhfGIPp/bt69v+DL/vPLUcNQBLbalAg1i40IL48a3Gs/xD7cTcp/iumKgakYu8gMczubIg1AA== 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=/OTcA6XGSbU1zKxGskg/jXcV77dDLe3ZiRIA5y2cGtE=; b=aiGELvql18frdy1CcXW1xAlLlA9RHVgkYa1F3PsS01kAHtu1TPOmzPVyPSo0Sz9+85T9MwssJ5brKoL+ErChFy/Mf9SHC8ZpXX0AQwvdLl+qV690gjGKwl9dUTZ4e4nLBllqmnXY14lw1SrGdIhElxTxiy0nL1HcIUl8SjRObq49OTHAA+0Lmz5aQhGNHK7+UDNCMpQ4OKR/hMFhNyPnE7+sa9wTNYpv5DT1jdPtfBnCc/AdEq3jbVpWdCZYCuE8/Bhf1cYLOS3GyiOI6P6o9v1ZMdtMxrIAe7Lvkds55M2LkprZLJak5AA5L4BbR7fNHh10Z2ITFyrxpGSF8e/+SA== 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=/OTcA6XGSbU1zKxGskg/jXcV77dDLe3ZiRIA5y2cGtE=; b=TWRo8Pq4kC021Iu5vZIhR3BdCbZBEYKRfcT8ZwIXroEG4dUcOwQ1vLYXKBwrwQBazZRwFpU9uNwVAmZ8KV58A8pH01SgGdvppwgTQ4TKmXZ40vFmNGBnmO3XY08hjy9M5iIphiGC6ghdbplARqaUIeIWDXgDwor5iscUC61SSEs5yzELpAB7lLw8GXm/XtK1CwAUOhAkwP/CupUUrbnb8CRUhbZj0yJXEEFlUvl4C8kHKf/eSPsPo+irwx+pYnOpJ7e/DwOILQH/Df+Or3MKAaOxZLYAVYluE1+ouXr8O3/uBgigke7bG01Y9so8Gu3jBQHbnFaGOAbFkaqeM4XGug== 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 LV0PR12MB999092.namprd12.prod.outlook.com (2603:10b6:408:32e::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.315.16; Sun, 16 Aug 2026 17:38:06 +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 15.21.0315.016; Sun, 16 Aug 2026 17:38:06 +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 , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 07/17] sched: Add sched_ext hooks for proxy execution Date: Sun, 16 Aug 2026 19:35:05 +0200 Message-ID: <20260816173732.17162-8-arighi@nvidia.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260816173732.17162-1-arighi@nvidia.com> References: <20260816173732.17162-1-arighi@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MI3PEPF00004E97.ITAP293.PROD.OUTLOOK.COM (2603:10a6:298:1::447) 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_|LV0PR12MB999092:EE_ X-MS-Office365-Filtering-Correlation-Id: ab078725-66fd-4912-c695-08defbbd21a1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|7416014|366016|376014|1800799024|22082099003|18002099003|10067099003|56012099006|11063799006; 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)(23010399003)(7416014)(366016)(376014)(1800799024)(22082099003)(18002099003)(10067099003)(56012099006)(11063799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JV2UKrsMuDuv3hdBJzKubUojQswjDOcAue5W8+0KzL5sloYvMlbdwve+4jhk?= =?us-ascii?Q?32eKEJ5KVs9c+UU4y0le3exPK4elnEwkcbTjFhrwiMILGnqfGQJHk0czckqB?= =?us-ascii?Q?dcG2pwkxStTsLEdbMDWQZeeypBDoObw9yCYNE+zfOmagfsBB6HMrSrQ77Y7Q?= =?us-ascii?Q?g0GUAR/PDnADhc6QywVD14edBg3o6frZLZ8kCT0Ztm2TeuMkI8JMEZ9bQPTT?= =?us-ascii?Q?U3uB4PKMhq2CIZFZF1MLpfkTbhHtZrXWzKXetVqXWpGvewMcGmr7g3fZNwef?= =?us-ascii?Q?HnkEGoUbKjM4ID+eBODY+itVftIrxAPYlDZlfo/rhszjgr9l6IxcAp6dXpYo?= =?us-ascii?Q?fJMKJ82ni3uZDsWdtkd+ChQTy1G7SCbnYFJhaDLsQqsg0flqFYEiTQV3PpT/?= =?us-ascii?Q?wVuYdNreqdjfAC1QjDMGaikFtQBGlPZ+0TTJN537z96rTbQY36OiLuAPy9SC?= =?us-ascii?Q?Qv/Sz/tB46aU9Y8OpNmfcGnHn7drBj4pRRvX1iIYZgIXaoR2/dq7j81eto98?= =?us-ascii?Q?O9Kd1gL3kx+9ztmUsfzVdiFqfVd6F4fxCITUjolAHdtbWmhFbDNkYuirqCum?= =?us-ascii?Q?f7KzKwZzfwHvc9ljpJosMuz5AfzWvtgo+GsX0URFXz7+nJXU5grUFVT1O47u?= =?us-ascii?Q?YGQUWsRcQthq2NZ2CdyUv/51HuRpF7RBNvHFQKN/bUuqxRbojZJo0JGqQRfp?= =?us-ascii?Q?epgau9pc7OcMkpZSP7IyY4BWEFx2zKWCJCIFuFsLoGdn2pg2mk6K0jpfdVpx?= =?us-ascii?Q?rof4u/bfuhR1w07FVjgIorCVEBJbMT4w7GezzP4Sotqve2AqfwKhbKEGEu0A?= =?us-ascii?Q?cVBwCSMHqF8oy479PHQzqZa4sWPM5+3bx7f2cTmW1t+HRliGOxMdNUbgqk5d?= =?us-ascii?Q?ye3snkYiV35yqYXzd77vJYyv3dWSvtaZZeRJ0LS+I38pcFME3h01WwJ765dC?= =?us-ascii?Q?Mde1fOSaz+wgpV520rgAQUS3HQzLdHBJpwkYMqvUCWDnmxIOv8jif1xO6Qka?= =?us-ascii?Q?3WSa32NYjKi7ACwuFFsCWahsKeINyUoHGxJSAlFP41aeCHax/ygsG+LzI6Eh?= =?us-ascii?Q?OzLKrA2lhr0PnHfBGeqWBjeq1LZ2T13x8A9K49nKtwy7ob4fY26PZYBG9l7Y?= =?us-ascii?Q?WgyGhhDJS1oIjKRh9CAheB0AiMGTX/usHu3yfB8HI1bFH10CPRhjiGeUsrSq?= =?us-ascii?Q?t0f92M4GjEMXT2OyCbrlumYw3sRVsrmRfcRnc24+XJKWRi9lI9xyehPtHAMZ?= =?us-ascii?Q?yCI7th5zRXzRuk1cA8fyYOFxiIIxRAovISjZnIaoKCtZnbi1KnGNpjvnGtbA?= =?us-ascii?Q?LEn2cmBElC3NpIf24eNTTodgy/ErD26PLtEfiggzcvVl8HOUNFxedUli/fq0?= =?us-ascii?Q?oycfoNpzG1xt+gUNxNXlA1WNh3C/A0oGVuys4MtiH+2S/333ORaPE/jTBbP/?= =?us-ascii?Q?CshJdOPtJlgxqBOdcJbUVOsn/qbklKL5nqLaUEef00uLJRS44n+ljDiO1Kwx?= =?us-ascii?Q?GaJxErLYQZyId040ZED561/o6zyibsioG5Q2otYwdCcwAkDx8gv3jJZQoPN/?= =?us-ascii?Q?oWLJaLo4d5H575oeX7EqpD61U+B+WTCAUKpmTh/7AOc4L2QHGd4v3/q/J9T5?= =?us-ascii?Q?gVC9NhGxYlkqH8+kR2ofP9jQeY0OWQnnW86GG1qzwdhVt0yLELR+zFNelyII?= =?us-ascii?Q?Mwrc/aVVqP1pvfnWYKJFGO852abFbZUgHC+zPveqPldjtNkho3vxFWsHDTNT?= =?us-ascii?Q?ZPsh4KdHIA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ab078725-66fd-4912-c695-08defbbd21a1 X-MS-Exchange-CrossTenant-AuthSource: DM6PR12MB4827.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Aug 2026 17:38:06.6358 (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: uctdspZcGX+8l+gIliJMXaneUOQs6MNF+7cR5IoxC8B9trD61+QK5uW2AdplqwSu0OxSCqC4j8NwjbVX3ttr1g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV0PR12MB999092 Proxy execution splits the scheduling context (the donor) from the execution context (the lock owner). sched_ext needs to observe that split at three points in __schedule(): - whether a blocked EXT task can be retained on the runqueue as a donor, - when a donor's scheduling context starts driving a lock owner, - once proxy resolution has settled for the current pick. Introduce scx_allow_proxy_exec(), scx_proxy_donor_start() and scx_proxy_resolved(), and add their call sites in __schedule(). The implementations are empty here and are filled in by the sched_ext changes that follow, so that all the sched core changes needed by proxy execution stay together in the preparatory patches. SCHED_PROXY_EXEC still depends on !SCHED_CLASS_EXT, so the new hooks are inert: they are compiled out with CONFIG_SCHED_CLASS_EXT=n and unreachable otherwise. This is a preparatory change to support proxy execution with sched_ext. No functional change. Signed-off-by: Andrea Righi --- kernel/sched/core.c | 12 +++++++----- kernel/sched/ext/ext.c | 13 +++++++++++++ kernel/sched/ext/ext.h | 6 ++++++ 3 files changed, 26 insertions(+), 5 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index bb2b7faefcdeb..ea432bf307c1d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7208,13 +7208,12 @@ static void __sched notrace __schedule(int sched_mode) } } else if (!preempt && prev_state) { /* - * We pass task_is_blocked() as the should_block arg - * in order to keep mutex-blocked tasks on the runqueue - * for slection with proxy-exec (without proxy-exec - * task_is_blocked() will always be false). + * Keep mutex-blocked tasks on the runqueue for proxy execution + * only when their scheduling class allows it. Without proxy + * execution, task_is_blocked() always returns false. */ try_to_block_task(rq, prev, &prev_state, - !task_is_blocked(prev)); + !task_is_blocked(prev) || !scx_allow_proxy_exec(prev)); switch_count = &prev->nvcsw; } @@ -7235,6 +7234,7 @@ static void __sched notrace __schedule(int sched_mode) } if (next == rq->idle) { zap_balance_callbacks(rq); + scx_proxy_resolved(rq); goto keep_resched; } } @@ -7255,6 +7255,8 @@ static void __sched notrace __schedule(int sched_mode) donor->sched_class->put_prev_task(rq, donor, donor); donor->sched_class->set_next_task(rq, donor, true); } + scx_proxy_donor_start(rq); + scx_proxy_resolved(rq); } else { rq_set_donor(rq, next); } diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 186a3f4e1a92f..6b1d9c98b8efa 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -24,6 +24,11 @@ DEFINE_RAW_SPINLOCK(scx_sched_lock); +bool scx_allow_proxy_exec(const struct task_struct *p) +{ + return true; +} + /* * NOTE: sched_ext is in the process of growing multiple scheduler support and * scx_root usage is in a transitional state. Naked dereferences are safe if the @@ -1078,6 +1083,10 @@ static void schedule_deferred_locked(struct rq *rq) schedule_deferred(rq); } +void scx_proxy_resolved(struct rq *rq) +{ +} + void schedule_dsq_reenq(struct scx_sched *sch, struct scx_dispatch_q *dsq, u64 reenq_flags, struct rq *locked_rq) { @@ -3061,6 +3070,10 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first) } } +void scx_proxy_donor_start(struct rq *rq) +{ +} + static enum scx_cpu_preempt_reason preempt_reason_from_class(const struct sched_class *class) { diff --git a/kernel/sched/ext/ext.h b/kernel/sched/ext/ext.h index 0b7fc46aee08c..859b9261a8a6b 100644 --- a/kernel/sched/ext/ext.h +++ b/kernel/sched/ext/ext.h @@ -20,6 +20,9 @@ void scx_rq_deactivate(struct rq *rq); int scx_check_setscheduler(struct task_struct *p, int policy); bool task_should_scx(int policy); bool scx_allow_ttwu_queue(const struct task_struct *p); +bool scx_allow_proxy_exec(const struct task_struct *p); +void scx_proxy_donor_start(struct rq *rq); +void scx_proxy_resolved(struct rq *rq); void init_sched_ext_class(void); static inline u32 scx_cpuperf_target(s32 cpu) @@ -54,6 +57,9 @@ static inline void scx_rq_deactivate(struct rq *rq) {} static inline int scx_check_setscheduler(struct task_struct *p, int policy) { return 0; } static inline bool task_on_scx(const struct task_struct *p) { return false; } static inline bool scx_allow_ttwu_queue(const struct task_struct *p) { return true; } +static inline bool scx_allow_proxy_exec(const struct task_struct *p) { return true; } +static inline void scx_proxy_donor_start(struct rq *rq) {} +static inline void scx_proxy_resolved(struct rq *rq) {} static inline void init_sched_ext_class(void) {} #endif /* CONFIG_SCHED_CLASS_EXT */ -- 2.55.0