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From: Peter Zijlstra <peterz@infradead.org>
To: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: mingo@kernel.org, longman@redhat.com, chenridong@huaweicloud.com,
	juri.lelli@redhat.com, vincent.guittot@linaro.org,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	jstultz@google.com, qyousef@layalina.io
Subject: Re: [PATCH v2 10/10] sched/eevdf: Move to a single runqueue
Date: Wed, 13 May 2026 09:25:59 +0200	[thread overview]
Message-ID: <20260513072559.GF1889694@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <dc4df15c-2f21-4141-ba7c-b2d8afbcd0c3@amd.com>

On Wed, May 13, 2026 at 12:31:05PM +0530, K Prateek Nayak wrote:
> Hello Peter,
> 
> On 5/12/2026 4:39 PM, Peter Zijlstra wrote:
> >> @@ -13819,6 +13831,12 @@ static void set_next_task_fair(struct rq *rq, struct task_struct *p, bool first)
> >>  		if (on_rq)
> >>  			weight = __calc_prop_weight(cfs_rq, se, weight);
> >>  	}
> >> +	/*
> >> +	 * Add throttle work if the bandwidth allocation above failed
> >> +	 * to grab any runtime and throttled the task's hierarchy.
> >> +	 */
> >> +	if (throttled_hierarchy(task_cfs_rq(p)))
> >> +		task_throttle_setup_work(p);
> > 
> > We already call into account_cfs_rq_runtime(); which basically does all
> > we need.
> > 
> > I think the distinction between account_cfs_rq_runtime() and
> > check_cfs_rq_runtime() no longer makes sense. We can throttle a cfs_rq
> > at any point now, since we no longer remove the cfs_rq, but rather we
> > make the tasks suspend themselves until the cfs_rq naturally dequeues
> > for being empty.
> > 
> > Something like so perhaps?
> 
> That makes sense! The task should naturally execute the task work when
> exiting out of the kernel / IRQ handler into the userspace so we should
> be good.
> 
> I'll rebase the below diff on tip, test it a bit, add a commit log, and
> send it your way if you don't mind or would you like to keep it with the
> flat_cg bits?

Nah, this seems like something that can be done independent. And thus is
should be. That flat patch is big enough as is.

  reply	other threads:[~2026-05-13  7:28 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-11 11:31 [PATCH v2 00/10] sched: Flatten the pick Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 01/10] sched/debug: Use char * instead of char (*)[] Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 02/10] sched: Use {READ,WRITE}_ONCE() for preempt_dynamic_mode Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 03/10] sched/debug: Collapse subsequent CONFIG_SCHED_CLASS_EXT sections Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 04/10] sched/fair: Add cgroup_mode switch Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 05/10] sched/fair: Add cgroup_mode: UP Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 06/10] sched/fair: Add cgroup_mode: MAX Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 07/10] sched/fair: Add cgroup_mode: CONCUR Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 08/10] sched/fair: Add newidle balance to pick_task_fair() Peter Zijlstra
2026-05-12  5:37   ` K Prateek Nayak
2026-05-12  9:45     ` Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 09/10] sched: Remove sched_class::pick_next_task() Peter Zijlstra
2026-05-11 11:31 ` [PATCH v2 10/10] sched/eevdf: Move to a single runqueue Peter Zijlstra
2026-05-11 16:21   ` K Prateek Nayak
2026-05-12 11:09     ` Peter Zijlstra
2026-05-13  7:01       ` K Prateek Nayak
2026-05-13  7:25         ` Peter Zijlstra [this message]
2026-05-13  4:51   ` John Stultz
2026-05-13  5:00     ` John Stultz
2026-05-11 19:23 ` [PATCH v2 00/10] sched: Flatten the pick Tejun Heo
2026-05-12  8:10   ` Peter Zijlstra
2026-05-12 18:45     ` Tejun Heo
2026-05-12  8:42 ` Vincent Guittot
2026-05-12  9:20   ` Peter Zijlstra
2026-05-12 18:24     ` Peter Zijlstra
2026-05-12 18:25       ` Peter Zijlstra
2026-05-12 18:32         ` Vincent Guittot
2026-05-13  7:25           ` Peter Zijlstra

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