Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 7 Dec 2020 16:48:38 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Aubrey Li <aubrey.li@linux.intel.com>
Cc:     mingo@redhat.com, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, mgorman@techsingularity.net,
        valentin.schneider@arm.com, qais.yousef@arm.com,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org,
        Mel Gorman <mgorman@suse.de>, Jiang Biao <benbjiang@gmail.com>
Subject: Re: [RFC PATCH v5] sched/fair: select idle cpu from idle cpumask for
 task wakeup
Message-ID: <20201207154838.GP3040@hirez.programming.kicks-ass.net>
References: <20201118043113.53128-1-aubrey.li@linux.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201118043113.53128-1-aubrey.li@linux.intel.com>
Precedence: bulk

On Wed, Nov 18, 2020 at 12:31:13PM +0800, Aubrey Li wrote:
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> index f324dc36fc43..6f5947673e66 100644
> --- a/kernel/sched/idle.c
> +++ b/kernel/sched/idle.c
> @@ -163,6 +163,7 @@ static void cpuidle_idle_call(void)
>  	 */
>  
>  	if (cpuidle_not_available(drv, dev)) {
> +		update_idle_cpumask(this_rq(), true);
>  		tick_nohz_idle_stop_tick();
>  
>  		default_idle_call();
> @@ -193,6 +194,7 @@ static void cpuidle_idle_call(void)
>  			max_latency_ns = dev->forced_idle_latency_limit_ns;
>  		}
>  
> +		update_idle_cpumask(this_rq(), true);
>  		tick_nohz_idle_stop_tick();
>  
>  		next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns);
> @@ -205,10 +207,12 @@ static void cpuidle_idle_call(void)
>  		 */
>  		next_state = cpuidle_select(drv, dev, &stop_tick);
>  
> -		if (stop_tick || tick_nohz_tick_stopped())
> +		if (stop_tick || tick_nohz_tick_stopped()) {
> +			update_idle_cpumask(this_rq(), true);
>  			tick_nohz_idle_stop_tick();

We already have a callback in tick_nohz_idle_stop_tick(), namely
nohz_balance_enter_idle().