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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 MWH0EPF000C6191.mail.protection.outlook.com (10.167.249.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.569.4 via Frontend Transport; Mon, 26 Oct 2026 04:32:43 +0000 Received: from satlexmb07.amd.com (10.181.42.216) 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 15.2.2562.53; Sun, 25 Oct 2026 23:32:42 -0500 Received: from [10.136.43.232] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.53 via Frontend Transport; Sun, 25 Oct 2026 23:32:34 -0500 Message-ID: <327337ed-6a9b-4ec5-ad5e-bacaaccb1553@amd.com> Date: Mon, 26 Oct 2026 10:02:28 +0530 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v33 1/7] sched/psi: Preserve sleep-persistent PSI flags on off-CPU sleeping dequeues To: John Stultz , LKML CC: David Stevens , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Juri Lelli , Vincent Guittot , Valentin Schneider , Suleiman Souhlal , Andrea Righi , Metin Kaya , Dietmar Eggemann , Steven Rostedt , Zimuzo Ezeozue , Waiman Long , Boqun Feng , "Paul E. McKenney" , Joel Fernandes , Qais Yousef , Xuewen Yan , kuyo chang , hupu , Zhan Xusheng , "zhidao su (Xiaomi)" , Hui Su , "Shubhang Kaushik (Ampere)" , References: <20261023220431.1106611-1-jstultz@google.com> <20261023220431.1106611-2-jstultz@google.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20261023220431.1106611-2-jstultz@google.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000C6191:EE_|CH3PR12MB9100:EE_ X-MS-Office365-Filtering-Correlation-Id: eb06453f-a67e-46e3-065c-08df331a2dc0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|23010399003|376014|7416014|1800799024|82310400026|4143699003|11063799006|5023799004|56012099006|261021121427099003|261021123027099003|261022105027099003|10067099003|18002099003|22082099003|3023799007; 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)(36860700016)(23010399003)(376014)(7416014)(1800799024)(82310400026)(4143699003)(11063799006)(5023799004)(56012099006)(261021121427099003)(261021123027099003)(261022105027099003)(10067099003)(18002099003)(22082099003)(3023799007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: sxGE4HSS8xZktM08/c6gGAlLqxqKN5xGV/iLpv5tWHk/9IcVJ79n0iOmXGNX5Bp+N87ADJyGAgBrTF9S5Z1/wHEhydg4vxIGl48YolIMwwc0F51PQ2m9O/fBJzwwoO24WGRT+fV+VERhvNSVmsc4oaI/+SMPdNVrpftcFqoI293zdI66wWD2MBhtheU8l7N5yscHCyXFjmea23WXMmGpCNOC6DAiLRDzuBwhd9KlXevjEzyjn0uDscY11PabDb9EQ3BQXwUOv6mOYMjqI3b5s1zhOBmkoDifLHuYHP0B6QlHo9SsIghuDJb33KdTivhVzEyKeIq+r1LaYEheP19xGLN52vs74mmOATnwM61WYNWfhZRriu2EN+YvD6R62JPldensD+A8oom0ZD8JzJZB7bU8P1PBAbr2QbrSPKmc5nIV+wW9BdhD2hAs8aKlP9g3 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Oct 2026 04:32:43.8317 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: eb06453f-a67e-46e3-065c-08df331a2dc0 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: MWH0EPF000C6191.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB9100 Hello John, On 10/24/2026 3:34 AM, John Stultz wrote: > diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h > index ebe0a7765f98e..20820fe1021a1 100644 > --- a/kernel/sched/stats.h > +++ b/kernel/sched/stats.h > @@ -175,12 +175,28 @@ static inline void psi_dequeue(struct task_struct *p, int flags) > * Do nothing here. > * > * In the SCHED_PROXY_EXECUTION case we may do sleeping > - * dequeues that are not followed by a task switch, so check > - * TSK_ONCPU is set to ensure the task switch is imminent. > - * Otherwise clear the flags as usual. > + * dequeues that are not followed by a task switch. If TSK_ONCPU > + * is not set (meaning we already switched away while the task > + * stayed on the rq as a blocked donor), handle the sleeping > + * state transition here so sleep-persistent states (TSK_MEMSTALL, > + * TSK_IOWAIT) are preserved. > */ > - if ((flags & DEQUEUE_SLEEP) && (p->psi_flags & TSK_ONCPU)) > + if (flags & DEQUEUE_SLEEP) { > + int clear = TSK_RUNNING, set = 0; nit. You can declare these on top with clear set to p->psi_flags and override them accordingly here ... > + > + if (p->psi_flags & TSK_ONCPU) > + return; > + if (p->se.sched_delayed) > + return; > + > + if (p->in_memstall) > + clear |= TSK_MEMSTALL_RUNNING; > + if (p->in_iowait) > + set |= TSK_IOWAIT; > + > + psi_task_change(p, clear, set); That way, we can have a single psi_task_change(p, clear, set) at the end instead of calling it here and doing an early return. > return; > + } > > /* > * When migrating a task to another CPU, clear all psi -- Thanks and Regards, Prateek