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Date: Fri, 12 Jul 2024 19:10:46 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Valentin Schneider <vschneid@redhat.com>
Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>, Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Phil Auld <pauld@redhat.com>, Clark Williams <williams@redhat.com>,
	Tomas Glozar <tglozar@redhat.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
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	Catalin Marinas <catalin.marinas@arm.com>,
	Arnd Bergmann <arnd@arndb.de>, Guo Ren <guoren@kernel.org>,
	Palmer Dabbelt <palmer@rivosinc.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Jens Axboe <axboe@kernel.dk>
Subject: Re: [RFC PATCH v3 10/10] sched/fair: Throttle CFS tasks on return to
 userspace
Message-ID: <20240712171046.GV27299@noisy.programming.kicks-ass.net>
References: <20240711130004.2157737-1-vschneid@redhat.com>
 <20240711130004.2157737-11-vschneid@redhat.com>
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In-Reply-To: <20240711130004.2157737-11-vschneid@redhat.com>

On Thu, Jul 11, 2024 at 03:00:04PM +0200, Valentin Schneider wrote:
> +static void task_throttle_cancel_irq_work_fn(struct irq_work *work)
> +{
> +	struct task_struct *p = container_of(work, struct task_struct, unthrottle_irq_work);
> +	int cpu = raw_smp_processor_id();
> +
> +	CLASS(task_rq_lock, rq_guard)(p);

	guard(task_rq_lock)(p);

> +	WARN_ON_ONCE(task_cpu(p) != cpu);
> +
> +	if (task_has_throttle_work(p) && !task_needs_throttling(p))
> +		task_throttle_do_cancel_work(p);
> +}