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Commit ff006732 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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timers/nohz: Remove pointless tick_nohz_kick_tick() function 



This was a failed attempt to optimize the timer expiry in idle, which was
disabled and never revisited. Remove the cruft.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160704094342.431073782@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 23696838

kernel/time/tick-sched.c

+1 −32
Original line number Diff line number Diff line
@@ -1092,35 +1092,6 @@ static void tick_nohz_switch_to_nohz(void) 
	tick_nohz_activate(ts, NOHZ_MODE_LOWRES);

}



/*

 * When NOHZ is enabled and the tick is stopped, we need to kick the

 * tick timer from irq_enter() so that the jiffies update is kept

 * alive during long running softirqs. That's ugly as hell, but

 * correctness is key even if we need to fix the offending softirq in

 * the first place.

 *

 * Note, this is different to tick_nohz_restart. We just kick the

 * timer and do not touch the other magic bits which need to be done

 * when idle is left.

 */

static void tick_nohz_kick_tick(struct tick_sched *ts, ktime_t now)

{

#if 0

	/* Switch back to 2.6.27 behaviour */

	ktime_t delta;



	/*

	 * Do not touch the tick device, when the next expiry is either

	 * already reached or less/equal than the tick period.

	 */

	delta =	ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);

	if (delta.tv64 <= tick_period.tv64)

		return;



	tick_nohz_restart(ts, now);

#endif

}



static inline void tick_nohz_irq_enter(void)

{

	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
@@ -1131,10 +1102,8 @@ static inline void tick_nohz_irq_enter(void) 
	now = ktime_get();

	if (ts->idle_active)

		tick_nohz_stop_idle(ts, now);

	if (ts->tick_stopped) {

	if (ts->tick_stopped)

		tick_nohz_update_jiffies(now);

		tick_nohz_kick_tick(ts, now);

	}

}



#else