From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011022.outbound.protection.outlook.com [40.107.208.22]) (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 A72FF3603C9 for ; Wed, 18 Mar 2026 17:55:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.208.22 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773856553; cv=fail; b=GYNZit5Kkajvu6aWRB3oX7j4zftV3CMSkQ8s6ihc/eAgiGyTJv1PLYnsatVOuEmrOPk4dZEV0Qo6SjJCJ+Qt4o3xA/aunzlWtpe3/HbBzU3SpXBDH4Gb2OxCZ8rl8hTXuZQYQqsYJYg4rAi8Bwu8dVFF7GPjFilzFHlDsjo/gKs= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773856553; c=relaxed/simple; bh=MsbVeA0yM+1aZXr/Kw8QeMuwgs1Z0kzomdQVBvZ/MgQ=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=m++4d+mhWE+4aj7p3204IZjEpZ9R/kXWq1fCyJ7SF4lFnUqoSgM+4Hum2SiUvnr+6F6Mq9oqx83FHnxooNfjl9txerywwm5qKmVCs9XwDELMJniDEMqAInyLDby0ay4448oTZligVb8VNk+57eP7w6HKSMRUvELoWkN3+ES8Htg= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=v/AsF2Fy; arc=fail smtp.client-ip=40.107.208.22 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="v/AsF2Fy" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=x6clwPF1yX8jHrZMmQHtaG4930gcR2iOXAQlohG8J6a4vVZPTDxVCMIPlVMsnRGoqxkR5O5rzVuaesINXFy87M13sDTK0x+4W6olwPjyIW+/6DY7Q5r8EcWnWdYghLi3cqt89BZA4CcIUZRE9j6FCygpe/U3yQ6SYAfaBV2KZEuJQJ2OO246M+WPB7VvpUo7N98WyjMVmtCW77BAyVlb5M+fFYe9v1mbL2AZNoIVRvCEndw5vFxYaNfa9QGKp1T4NvrNcx0CGvTq2fhKzVL9/GK8aV+ENY2C5IfAqoBeFCdkUEkPQEp6xGZDnq2EvB6kAB8d6qoCqwpj4ieIZvgGuw== 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=UPjJfTStTZZgT09EAucH4JxOtjV9ctTmEDcSAGC4SAI=; b=MkrzhTYkBudp9AvUd8wftnc0TALx6s6FtFnZ9oxkU+4PZlWx32lS2xoSfLzr8kcGrVkKxqOMewet7dd1EgmWe2QksHykHJRgCwSux/3aQIMCFFl/IPhvijpKVs6dnraN/y9lZ2U3YepWBQA85NCcXr4FbuJ/Wiakid6KAMTYjJf250fyWL+qKiHMe2Nw0lXqJ8JgDLkCqH5TZC/I0IbtCdk3XIui/1VpEBNJ2+tNkAgiuazA3HtTjTU5LaA5/iHPWw+AilL8pl3aFsP4nqfXcHl41xfsofEMwgnFb68RmNXNagFPyNNQEAsTcffmjkbWdG9sL4X5N5vcQs5G1p3EEQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=infradead.org smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=UPjJfTStTZZgT09EAucH4JxOtjV9ctTmEDcSAGC4SAI=; b=v/AsF2FyImMjUF/+s7ALl66hRQSn0m4fAvOfYvzhlA0pKtDkOew2nyyjZldiagC5vXyta3Nd/4V6M3c6RNVGr+PhITK/mdm2XeLpVH5aMpjStTTrhqgTC2m5eUVhtuXtIws81yVwDCfz5uI9MYKOJE4884/S6pD3yxG0uawOROk= Received: from DS0PR17CA0014.namprd17.prod.outlook.com (2603:10b6:8:191::10) by MW4PR12MB6825.namprd12.prod.outlook.com (2603:10b6:303:20d::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19; Wed, 18 Mar 2026 17:55:43 +0000 Received: from DS2PEPF00003446.namprd04.prod.outlook.com (2603:10b6:8:191:cafe::e6) by DS0PR17CA0014.outlook.office365.com (2603:10b6:8:191::10) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9700.27 via Frontend Transport; Wed, 18 Mar 2026 17:55:39 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by DS2PEPF00003446.mail.protection.outlook.com (10.167.17.73) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.19 via Frontend Transport; Wed, 18 Mar 2026 17:55:43 +0000 Received: from satlexmb10.amd.com (10.181.42.219) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Wed, 18 Mar 2026 12:55:34 -0500 Received: from satlexmb08.amd.com (10.181.42.217) by satlexmb10.amd.com (10.181.42.219) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Wed, 18 Mar 2026 12:55:34 -0500 Received: from [172.31.184.125] (10.180.168.240) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Wed, 18 Mar 2026 12:55:26 -0500 Message-ID: Date: Wed, 18 Mar 2026 23:25:25 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v25 1/9] sched: Make class_schedulers avoid pushing current, and get rid of proxy_tag_curr() To: Peter Zijlstra , John Stultz CC: LKML , Joel Fernandes , Qais Yousef , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Ben Segall , Zimuzo Ezeozue , Mel Gorman , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , Thomas Gleixner , Daniel Lezcano , "Suleiman Souhlal" , kuyo chang , hupu , References: <20260313023022.2902479-1-jstultz@google.com> <20260313023022.2902479-2-jstultz@google.com> <20ea3670-c30a-433b-a07f-c4ff98ae2379@amd.com> <20260318133640.GJ3738010@noisy.programming.kicks-ass.net> <20260318135202.GA3739106@noisy.programming.kicks-ass.net> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260318135202.GA3739106@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS2PEPF00003446:EE_|MW4PR12MB6825:EE_ X-MS-Office365-Filtering-Correlation-Id: 550b2e96-6e94-4c68-b27c-08de85179360 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|82310400026|36860700016|18002099003|56012099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(82310400026)(36860700016)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 9l3bnccsI60p+rFQHqSppRQhMi8O2Eb5taw78biLGdisdE2RooLNkRzc/5JqOwabod/EN0SXYdKMk0wI+ey0H96JMYnKmGIMY2IWVLaMLUPJs0OXKwK2VL01jedxcjQi3XJ9qSc46Ke7pKZ2SNnkQfg+Jw0s4opQVuIV+I9eRflRjNRn5gmRqxJeHOzjA1QZF6tE283eU1Ebb77wVhxWLYwGWZUElFwHPkSbOZwmd+6YsyyvbX9PuIHZUTFrcdreVI7xPy3tMXr4OMnPGeBy74ZRl0MrJcoIbkL6/LY+f3MWa9zXEriCbw6Ylv+DvZUR2Pk3Q1b0XwRfctGjD2U0AWn50McR6CzAzO90ycZYrooa96XXclVpVfsJLjp/D86JWmf2+I/HdrosYrPaLdA0ynepQa2qwekKeCuxt/nFCHgSRvEsmMVZttjZ1HA0G21A X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Mar 2026 17:55:43.5937 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 550b2e96-6e94-4c68-b27c-08de85179360 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS2PEPF00003446.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB6825 Hello Peter, On 3/18/2026 7:22 PM, Peter Zijlstra wrote: >> @@ -7114,6 +7119,24 @@ static void __sched notrace __schedule(i >> goto keep_resched; >> } >> } >> + >> + /* >> + * When transitioning like: >> + * >> + * prev next >> + * donor: B B >> + * curr: A B Even for curr going A -> C, we should do this. Consider B is blocked on C which is in turn blocked on A. B gets picked and proxies A first as a result of the wait chain (B -> C -> A) A runs and does an unlock with a handoff to C clearing its blocked_on. In schedule B is picked again but this time it proxies C. A might be on the push list and was skipped last time around since A->on_cpu = 1 but now that is gone and we should still do put_prev_task() + set_next_task(). >> + * >> + * then put_prev_set_next_task() will not have done anything, >> + * since B == B. However, A might have missed a RT/DL balance >> + * opportunity due to being on_cpu. >> + */ >> + if (next == rq->donor && next == prev_donor) { > > && next != prev > >> + next->sched_class->put_prev_task(rq, next, next); >> + next->sched_class->set_next_task(rq, next, true); >> + } >> + } else { >> + rq_set_donor(rq, next); >> } >> picked: >> clear_tsk_need_resched(prev); -- Thanks and Regards, Prateek