From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1751616AbcFXUp0 (ORCPT <rfc822;w@1wt.eu>);
	Fri, 24 Jun 2016 16:45:26 -0400
Received: from mail-wm0-f68.google.com ([74.125.82.68]:34258 "EHLO
	mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751197AbcFXUpZ (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 24 Jun 2016 16:45:25 -0400
Date: Fri, 24 Jun 2016 22:45:20 +0200
From: Richard Cochran <richardcochran@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Eric Dumazet <edumazet@google.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Chris Mason <clm@fb.com>,
        Arjan van de Ven <arjan@infradead.org>, rt@linutronix.de,
        Rik van Riel <riel@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        George Spelvin <linux@sciencehorizons.net>,
        Len Brown <lenb@kernel.org>, Josh Triplett <josh@joshtriplett.org>
Subject: Re: [patch V3 19/22] timer: Forward wheel clock whenever possible
Message-ID: <20160624204519.GA13368@netboy>
References: <20160624140325.554996200@linutronix.de>
 <20160624141723.016280325@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20160624141723.016280325@linutronix.de>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Jun 24, 2016 at 02:32:19PM -0000, Thomas Gleixner wrote:
> @@ -809,6 +815,12 @@ static void tick_nohz_restart_sched_tick
>  	tick_do_update_jiffies64(now);
>  	cpu_load_update_nohz_stop();
>  
> +	/*
> +	 * Clear the timer idle flag, so we avoid IPIs on remote queueing and
> +	 * the clock forward checks in the enqueue path.
> +	 */
> +	timer_clear_idle();

Since function calls timer_clear_idle() already ...

>  	calc_load_exit_idle();
>  	touch_softlockup_watchdog_sched();
>  	/*
> @@ -1025,6 +1037,7 @@ void tick_nohz_idle_exit(void)
>  		tick_nohz_stop_idle(ts, now);
>  
>  	if (ts->tick_stopped) {
> +		timer_clear_idle();
>  		tick_nohz_restart_sched_tick(ts, now);
>  		tick_nohz_account_idle_ticks(ts);
>  	}

... there is no need to call timer_clear_idle() here.

Thanks,
Richard