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client-ip=165.204.84.17; helo=satlexmb08.amd.com; pr=C Received: from satlexmb08.amd.com (165.204.84.17) by BY1PEPF0001AE18.mail.protection.outlook.com (10.167.242.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.181.6 via Frontend Transport; Thu, 25 Jun 2026 06:24:11 +0000 Received: from satlexmb10.amd.com (10.181.42.219) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.41; Thu, 25 Jun 2026 01:24:11 -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 15.2.2562.41; Thu, 25 Jun 2026 01:24:11 -0500 Received: from [10.136.35.225] (10.180.168.240) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server id 15.2.2562.41 via Frontend Transport; Thu, 25 Jun 2026 01:24:08 -0500 Message-ID: <07c84814-bbca-4c94-aebb-5ac0858efcfc@amd.com> Date: Thu, 25 Jun 2026 11:54:02 +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 1/6 v3] sched/fair: Set next buddy for preempt short To: Vincent Guittot , , , , , , , , , , References: <20260624151229.1710703-1-vincent.guittot@linaro.org> <20260624151229.1710703-2-vincent.guittot@linaro.org> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260624151229.1710703-2-vincent.guittot@linaro.org> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: +4Zy6PCqSpdOmWbX4pX7Hf970GM27yg0KMo60MspukJQbUy65BBrlRJYnftG1RB+WvnXdFfw1oo36GTVAFfh8spOXXtTbtUwOUGuZgH/b3glzHsDV6XnuODJiJM3aKy75GzbJr6dBprczmH9kZMODlZwCsPYOyCYGQRCJVAILELUtXrCSOLzxh220tb7pTG8tewlGqqGMbIIGtZmuAV29WG9Yru4vLXD93ZJ92OE6WSQ0UKn6fgvOl4//mDjP61bJHXepqb7UtuDLsjX6Io5KD3J3twtw3L3w1iFKX4ifPDVVzKSQEU929hL4c3B5HXxs/CIMEYGyZ1+C2lae8qftmqG6P8nOfRUheYVMQt91j5cjsXHmQutpa/6MtBmk3L9v9AkvNO0c29D7LvmqBxLli3gYdWwSeG+jKEAk6esqm5tkKqZ5szkBeVyqqumpgKu X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Jun 2026 06:24:11.9891 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 41b20043-1f6a-4104-ec49-08ded2825f63 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=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BY1PEPF0001AE18.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DSWPR12MB999154 Hello Vincent, On 6/24/2026 8:42 PM, Vincent Guittot wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index d78467ec6ee1..83bce5a04f3d 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -9903,7 +9903,7 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f > preempt: > if (preempt_action == PREEMPT_WAKEUP_SHORT) { > cancel_protect_slice(se); > - clear_buddies(cfs_rq, se); > + set_next_buddy(&p->se); > } On a tangential note, I just noticed set_preempt_buddy() has two unused parameters. Seems to have been like that since it was introduced in commit e837456fdca8 ("sched/fair: Reimplement NEXT_BUDDY to align with EEVDF goals"). Perhaps this can be included in the series too as a cleanup: diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7c541f27a1ed..34b3888c4ccf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9755,9 +9755,7 @@ enum preempt_wakeup_action { PREEMPT_WAKEUP_RESCHED, /* Force reschedule. */ }; -static inline bool -set_preempt_buddy(struct cfs_rq *cfs_rq, int wake_flags, - struct sched_entity *pse, struct sched_entity *se) +static inline bool set_preempt_buddy(struct cfs_rq *cfs_rq, struct sched_entity *pse) { /* * Keep existing buddy if the deadline is sooner than pse. @@ -9903,9 +9901,7 @@ static void wakeup_preempt_fair(struct rq *rq, struct task_struct *p, int wake_f goto update; /* Prefer picking wakee soon if appropriate. */ - if (sched_feat(NEXT_BUDDY) && - set_preempt_buddy(cfs_rq, wake_flags, pse, se)) { - + if (sched_feat(NEXT_BUDDY) && set_preempt_buddy(cfs_rq, pse)) { /* * Decide whether to obey WF_SYNC hint for a new buddy. Old * buddies are ignored as they may not be relevant to the -- Thanks and Regards, Prateek