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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: 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
Subject: [patch 17/20] tick/sched: Remove pointless empty function
Date: Mon, 13 Jun 2016 08:41:03 -0000	[thread overview]
Message-ID: <20160613075929.606720592@linutronix.de> (raw)
In-Reply-To: 20160613070440.950649741@linutronix.de

[-- Attachment #1: tick-sched--Remove-pointless-empty-function.patch --]
[-- Type: text/plain, Size: 1851 bytes --]

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

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/tick-sched.c |   33 +--------------------------------
 1 file changed, 1 insertion(+), 32 deletions(-)

Index: b/kernel/time/tick-sched.c
===================================================================
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1092,35 +1092,6 @@ static void tick_nohz_switch_to_nohz(voi
 	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(v
 	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

  parent reply	other threads:[~2016-06-13  8:44 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-13  8:40 [patch 00/20] timer: Refactor the timer wheel Thomas Gleixner
2016-06-13  8:40 ` [patch 01/20] timer: Make pinned a timer property Thomas Gleixner
2016-06-13  8:40 ` [patch 02/20] x86/apic/uv: Initialize timer as pinned Thomas Gleixner
2016-06-13  8:40 ` [patch 03/20] x86/mce: " Thomas Gleixner
2016-06-13  8:40 ` [patch 04/20] cpufreq/powernv: " Thomas Gleixner
2016-06-13 13:18   ` Arjan van de Ven
2016-06-13  8:40 ` [patch 05/20] driver/net/ethernet/tile: " Thomas Gleixner
2016-06-13  8:40 ` [patch 06/20] drivers/tty/metag_da: " Thomas Gleixner
2016-06-13 13:13   ` Arjan van de Ven
2016-06-13  8:40 ` [patch 07/20] drivers/tty/mips_ejtag: " Thomas Gleixner
2016-06-13  8:40 ` [patch 08/20] net/ipv4/inet: Initialize timers " Thomas Gleixner
2016-06-13  8:40 ` [patch 09/20] timer: Remove mod_timer_pinned Thomas Gleixner
2016-06-13  8:40 ` [patch 10/20] timer: Add a cascading tracepoint Thomas Gleixner
2016-06-13  8:40 ` [patch 11/20] hlist: Add hlist_is_last_node() helper Thomas Gleixner
2016-06-13 10:27   ` Paolo Bonzini
2016-06-13  8:40 ` [patch 12/20] timer: Give a few structs and members proper names Thomas Gleixner
2016-06-13  8:41 ` [patch 13/20] timer: Switch to a non cascading wheel Thomas Gleixner
2016-06-13 11:40   ` Peter Zijlstra
2016-06-13 12:30     ` Thomas Gleixner
2016-06-13 12:46       ` Eric Dumazet
2016-06-13 14:30         ` Thomas Gleixner
2016-06-14 10:11       ` Ingo Molnar
2016-06-14 16:28         ` Thomas Gleixner
2016-06-14 17:14           ` Arjan van de Ven
2016-06-14 18:05             ` Thomas Gleixner
2016-06-14 20:34               ` Peter Zijlstra
2016-06-14 20:42               ` Peter Zijlstra
2016-06-14 21:17                 ` Eric Dumazet
2016-06-15 14:53                   ` Thomas Gleixner
2016-06-15 14:55                     ` Arjan van de Ven
2016-06-15 16:43                       ` Thomas Gleixner
2016-06-16 15:43                         ` Thomas Gleixner
2016-06-16 16:02                           ` Paul E. McKenney
2016-06-16 18:14                             ` Peter Zijlstra
2016-06-17  0:40                               ` Paul E. McKenney
2016-06-17  4:04                                 ` Paul E. McKenney
2016-06-16 16:04                           ` Arjan van de Ven
2016-06-16 16:09                             ` Thomas Gleixner
2016-06-15 15:05                     ` Eric Dumazet
2016-06-13 14:36   ` Richard Cochran
2016-06-13 14:39     ` Thomas Gleixner
2016-06-13  8:41 ` [patch 15/20] timer: Move __run_timers() function Thomas Gleixner
2016-06-13  8:41 ` [patch 14/20] timer: Remove slack leftovers Thomas Gleixner
2016-06-13  8:41 ` [patch 16/20] timer: Optimize collect timers for NOHZ Thomas Gleixner
2016-06-13  8:41 ` Thomas Gleixner [this message]
2016-06-13  8:41 ` [patch 18/20] timer: Forward wheel clock whenever possible Thomas Gleixner
2016-06-13 15:14   ` Richard Cochran
2016-06-13 15:18     ` Thomas Gleixner
2016-06-13  8:41 ` [patch 19/20] timer: Split out index calculation Thomas Gleixner
2016-06-13  8:41 ` [patch 20/20] timer: Optimization for same expiry time in mod_timer() Thomas Gleixner
2016-06-13 14:10 ` [patch 00/20] timer: Refactor the timer wheel Eric Dumazet
2016-06-13 16:15 ` Paul E. McKenney
2016-06-15 15:15   ` Paul E. McKenney
2016-06-15 17:02     ` Thomas Gleixner
2016-06-15 20:26       ` Paul E. McKenney

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