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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by SA2PEPF00001506.mail.protection.outlook.com (10.167.242.38) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8655.12 via Frontend Transport; Fri, 25 Apr 2025 03:48:55 +0000 Received: from [10.136.38.60] (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Thu, 24 Apr 2025 22:48:52 -0500 Message-ID: <3fb752bb-793d-4c0b-bf7f-12d04a4e7cc0@amd.com> Date: Fri, 25 Apr 2025 09:18:14 +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 V2 1/3] Sched: Scheduler time slice extension To: Prakash Sangappa , Sebastian Andrzej Siewior CC: "linux-kernel@vger.kernel.org" , "peterz@infradead.org" , "rostedt@goodmis.org" , "mathieu.desnoyers@efficios.com" , "tglx@linutronix.de" References: <20250418193410.2010058-1-prakash.sangappa@oracle.com> <20250418193410.2010058-2-prakash.sangappa@oracle.com> <20250424141345.7F42GFmZ@linutronix.de> Content-Language: en-US From: K Prateek Nayak In-Reply-To: Content-Type: text/plain; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Apr 2025 03:48:55.2634 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: da0593e2-5dd1-47df-2834-08dd83ac1a2d 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=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SA2PEPF00001506.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB7560 Hello Prakash, On 4/25/2025 6:49 AM, Prakash Sangappa wrote: >>> static void hrtick_clear(struct rq *rq) >>> { >>> + rseq_delay_resched_tick(); >> This is called from __schedule(). If you set the need-resched flag here, >> it gets removed shortly after. Do I miss something? > hrtick_clear() is also called when the cpu is being removed in sched_cpu_dying(). > We need to set resched there? sched_cpu_dying() is called from the cpuhp thread which will go away once the hotplug is done and shouldn't need this. Furthermore, cpuhp thread will not use the "rseq_sched_delay" API so removing this should be fine. -- Thanks and Regards, Prateek