linux-kernel - Re: [RFC PATCH v5] sched/fair: select idle cpu from idle cpumask for task wakeup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 7 Dec 2020 16:48:38 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Aubrey Li <aubrey.li@...ux.intel.com>
Cc:     mingo@...hat.com, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, mgorman@...hsingularity.net,
        valentin.schneider@....com, qais.yousef@....com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        tim.c.chen@...ux.intel.com, linux-kernel@...r.kernel.org,
        Mel Gorman <mgorman@...e.de>, Jiang Biao <benbjiang@...il.com>
Subject: Re: [RFC PATCH v5] sched/fair: select idle cpu from idle cpumask for
 task wakeup

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().