linux-kernel - [PATCH 10/32] nohz: Move next idle expiring time record into idle logic area

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Date:	Mon, 15 Aug 2011 17:52:07 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Anton Blanchard <anton@....ibm.com>,
	Avi Kivity <avi@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
	Paul Menage <menage@...gle.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Stephen Hemminger <shemminger@...tta.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Tim Pepper <lnxninja@...ux.vnet.ibm.com>
Subject: [PATCH 10/32] nohz: Move next idle expiring time record into idle logic area

Move next idle expiry time record and idle sleeps tracking into
idle entry functions as they are not generic nohz stats.

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Anton Blanchard <anton@....ibm.com>
Cc: Avi Kivity <avi@...hat.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Lai Jiangshan <laijs@...fujitsu.com>
Cc: Paul E . McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Paul Menage <menage@...gle.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Stephen Hemminger <shemminger@...tta.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tim Pepper <lnxninja@...ux.vnet.ibm.com>
---
 kernel/time/tick-sched.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2794150..f5e12da 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -249,10 +249,10 @@ EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
  * Called either from the idle loop or from irq_exit() when an idle period was
  * just interrupted by an interrupt which did not cause a reschedule.
  */
-static void tick_nohz_stop_sched_tick(ktime_t now, int cpu, struct tick_sched *ts)
+static ktime_t tick_nohz_stop_sched_tick(ktime_t now, int cpu, struct tick_sched *ts)
 {
 	unsigned long seq, last_jiffies, next_jiffies, delta_jiffies;
-	ktime_t last_update, expires;
+	ktime_t last_update, expires, ret = { .tv64 = 0 };
 	struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
 	u64 time_delta;
 
@@ -338,6 +338,8 @@ static void tick_nohz_stop_sched_tick(ktime_t now, int cpu, struct tick_sched *t
 		if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
 			goto out;
 
+		ret = expires;
+
 		/*
 		 * nohz_stop_sched_tick can be called several times before
 		 * the nohz_restart_sched_tick is called. This happens when
@@ -350,11 +352,6 @@ static void tick_nohz_stop_sched_tick(ktime_t now, int cpu, struct tick_sched *t
 			ts->tick_stopped = 1;
 		}
 
-		ts->idle_sleeps++;
-
-		/* Mark expires */
-		ts->idle_expires = expires;
-
 		/*
 		 * If the expiration time == KTIME_MAX, then
 		 * in this case we simply stop the tick timer.
@@ -386,6 +383,8 @@ out:
 	ts->next_jiffies = next_jiffies;
 	ts->last_jiffies = last_jiffies;
 	ts->sleep_length = ktime_sub(dev->next_event, now);
+
+	return ret;
 }
 
 static bool tick_nohz_can_stop_tick(int cpu, struct tick_sched *ts)
@@ -424,7 +423,7 @@ static bool tick_nohz_can_stop_tick(int cpu, struct tick_sched *ts)
 
 static void __tick_nohz_enter_idle(struct tick_sched *ts, int cpu)
 {
-	ktime_t now;
+	ktime_t now, expires;
 
 	now = tick_nohz_start_idle(cpu, ts);
 
@@ -432,7 +431,11 @@ static void __tick_nohz_enter_idle(struct tick_sched *ts, int cpu)
 		int was_stopped = ts->tick_stopped;
 
 		ts->idle_calls++;
-		tick_nohz_stop_sched_tick(now, cpu, ts);
+		expires = tick_nohz_stop_sched_tick(now, cpu, ts);
+		if (expires.tv64 > 0LL) {
+			ts->idle_sleeps++;
+			ts->idle_expires = expires;
+		}
 
 		if (!was_stopped && ts->tick_stopped) {
 			ts->idle_jiffies = ts->last_jiffies;
-- 
1.7.5.4

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