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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org,
	juri.lelli@redhat.com, vincent.guittot@linaro.org,
	dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
	mgorman@suse.de, vschneid@redhat.com, ankur.a.arora@oracle.com,
	efault@gmx.de
Subject: Re: [PATCH 1/5] sched: Add TIF_NEED_RESCHED_LAZY infrastructure
Message-ID: <20241009121859.C2-B8P4L@linutronix.de>
References: <20241007074609.447006177@infradead.org>
 <20241007075055.219540785@infradead.org>
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In-Reply-To: <20241007075055.219540785@infradead.org>

On 2024-10-07 09:46:10 [+0200], Peter Zijlstra wrote:
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -964,9 +963,9 @@ static bool set_nr_if_polling(struct tas
>  }
>  
>  #else
> -static inline bool set_nr_and_not_polling(struct task_struct *p)
> +static inline bool set_nr_and_not_polling(struct thread_info *ti, int tif)
>  {
> -	set_tsk_need_resched(p);
> +	atomic_long_or(1 << tif, (atomic_long_t *)&ti->flags);

	set_ti_thread_flag(ti, tif);
?
Not sure if there is a benefit over atomic_long_or() but you could avoid
the left shift. I know. Performance critical.

>  	return true;
>  }
>  

Sebastian