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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 McKenney <paulmck@linux.vnet.ibm.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>,
	George Spelvin <linux@sciencehorizons.net>,
	Len Brown <lenb@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Eric Dumazet <edumazet@google.com>
Subject: [patch 4 18/22] tick/sched: Remove pointless empty function
Date: Mon, 04 Jul 2016 09:50:35 -0000
Message-ID: <20160704094342.431073782@linutronix.de> (raw)
In-Reply-To: <20160704093956.299369787@linutronix.de>


[-- Attachment #0: ticksched_Remove_pointless_empty_function.patch --]
[-- Type: text/plain, Size: 2021 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>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Mason <clm@fb.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: rt@linutronix.de
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>

---
 kernel/time/tick-sched.c |   33 +--------------------------------
 1 file changed, 1 insertion(+), 32 deletions(-)

--- 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 index

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-04  9:50 [patch 4 00/22] timer: Refactor the timer wheel Thomas Gleixner
2016-07-04  9:50 ` [patch 4 01/22] timer: Make pinned a timer property Thomas Gleixner
2016-07-07  8:39   ` [tip:timers/core] timers: Make 'pinned' " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 02/22] x86/apic/uv: Initialize timer as pinned Thomas Gleixner
2016-07-07  8:40   ` [tip:timers/core] timers, x86/apic/uv: Initialize the UV heartbeat " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 03/22] x86/mce: Initialize " Thomas Gleixner
2016-07-07  8:40   ` [tip:timers/core] timers, x86/mce: Initialize MCE restart " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 04/22] cpufreq/powernv: Initialize " Thomas Gleixner
2016-07-07  8:41   ` [tip:timers/core] timers, cpufreq/powernv: Initialize the gpstate " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 05/22] driver/net/ethernet/tile: Initialize " Thomas Gleixner
2016-07-07  8:41   ` [tip:timers/core] timers, driver/net/ethernet/tile: Initialize the egress " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 06/22] drivers/tty/metag_da: Initialize " Thomas Gleixner
2016-07-07  8:42   ` [tip:timers/core] timers, drivers/tty/metag_da: Initialize the poll " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 07/22] drivers/tty/mips_ejtag: Initialize " Thomas Gleixner
2016-07-07  8:42   ` [tip:timers/core] timers, drivers/tty/mips_ejtag: Initialize the poll " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 08/22] net/ipv4/inet: Initialize timers " Thomas Gleixner
2016-07-07  8:43   ` [tip:timers/core] timers, net/ipv4/inet: Initialize connection request " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 09/22] timer: Remove mod_timer_pinned Thomas Gleixner
2016-07-07  8:43   ` [tip:timers/core] timers: Remove the deprecated mod_timer_pinned() API tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 10/22] signal: Use hrtimer for sigtimedwait Thomas Gleixner
2016-07-07  8:43   ` [tip:timers/core] signals: Use hrtimer for sigtimedwait() tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 11/22] hlist: Add hlist_is_singular_node() helper Thomas Gleixner
2016-07-07  8:44   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 12/22] timer: Give a few structs and members proper names Thomas Gleixner
2016-07-07  8:44   ` [tip:timers/core] timers: " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 13/22] timer: Reduce the CPU index space to 256k Thomas Gleixner
2016-07-07  8:45   ` [tip:timers/core] timers: " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 14/22] timer: Switch to a non cascading wheel Thomas Gleixner
2016-07-07  8:45   ` [tip:timers/core] timers: Switch to a non-cascading wheel tip-bot for Thomas Gleixner
2016-08-11 15:21   ` [patch 4 14/22] timer: Switch to a non cascading wheel Jouni Malinen
2016-08-11 20:25     ` [PREEMPT-RT] " rcochran
2016-08-13  9:12       ` Jouni Malinen
2016-08-16  9:46         ` Richard Cochran
2016-08-16 14:35           ` Eric Dumazet
2016-08-17  9:05           ` Jouni Malinen
2016-08-17  9:23             ` rcochran
2016-08-12 17:50     ` Rik van Riel
2016-08-12 19:14       ` Paul E. McKenney
2016-08-16  8:55         ` Richard Cochran
2016-08-16  7:57       ` Richard Cochran
2016-07-04  9:50 ` [patch 4 15/22] timer: Remove slack leftovers Thomas Gleixner
2016-07-07  8:46   ` [tip:timers/core] timers: Remove set_timer_slack() leftovers tip-bot for Thomas Gleixner
2016-07-22 11:31   ` [patch 4 15/22] timer: Remove slack leftovers Jason A. Donenfeld
2016-07-22 13:04     ` Thomas Gleixner
2016-07-22 15:18       ` Jason A. Donenfeld
2016-07-22 22:54         ` Jason A. Donenfeld
2016-07-04  9:50 ` [patch 4 16/22] timer: Move __run_timers() function Thomas Gleixner
2016-07-07  8:46   ` [tip:timers/core] timers: " tip-bot for Anna-Maria Gleixner
2016-07-04  9:50 ` [patch 4 17/22] timer: Optimize collect timers for NOHZ Thomas Gleixner
2016-07-07  8:47   ` [tip:timers/core] timers: Optimize collect_expired_timers() " tip-bot for Anna-Maria Gleixner
2016-07-04  9:50 ` Thomas Gleixner [this message]
2016-07-07  8:47   ` [tip:timers/core] timers/nohz: Remove pointless tick_nohz_kick_tick() function tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 19/22] timer: Forward wheel clock whenever possible Thomas Gleixner
2016-07-07  8:48   ` [tip:timers/core] timers: Forward the " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 20/22] timer: Only wake softirq if necessary Thomas Gleixner
2016-07-07  8:48   ` [tip:timers/core] timers: " tip-bot for Thomas Gleixner
2016-07-04  9:50 ` [patch 4 21/22] timer: Split out index calculation Thomas Gleixner
2016-07-07  8:48   ` [tip:timers/core] timers: " tip-bot for Anna-Maria Gleixner
2016-07-04  9:50 ` [patch 4 22/22] timer: Optimization for same expiry time in mod_timer() Thomas Gleixner
2016-07-07  8:49   ` [tip:timers/core] timers: Implement optimization " tip-bot for Anna-Maria Gleixner

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