linux-kernel - [PATCH 2/7] sched: introduce a function to update the idle statistics

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Date:	Sun, 18 Apr 2010 12:01:22 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	linux-kernel@...r.kernel.org
Cc:	Arjan van de Ven <arjan@...radead.org>, akpm@...ux-foundation.org,
	mingo@...e.hu, peterz@...radead.org, tglx@...utronix.de,
	davej@...hat.com, cpufreq@...r.kernel.org
Subject: [PATCH 2/7] sched: introduce a function to update the idle
 statistics

>From 166b7526ccfea8b44626b6023ff5b0a8eb869bb3 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@...ux.intel.com>
Date: Sun, 18 Apr 2010 10:33:02 -0700
Subject: [PATCH 2/7] sched: introduce a function to update the idle statistics

Currently, two places update the idle statistics (and more to
come later in this series).

This patch creates a helper function for updating these statistics.

Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>
---
 kernel/time/tick-sched.c |   29 +++++++++++++++++++----------
 1 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 54dc155..ca2211d 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -150,14 +150,25 @@ static void tick_nohz_update_jiffies(ktime_t now)
 	touch_softlockup_watchdog();
 }
 
-static void tick_nohz_stop_idle(int cpu, ktime_t now)
+/*
+ * Updates the per cpu time idle statistics counters
+ */
+static void update_ts_time_stats(struct tick_sched *ts, ktime_t now)
 {
-	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
 	ktime_t delta;
 
-	delta = ktime_sub(now, ts->idle_entrytime);
 	ts->idle_lastupdate = now;
-	ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+	if (ts->idle_active) {
+		delta = ktime_sub(now, ts->idle_entrytime);
+		ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+	}
+}
+
+static void tick_nohz_stop_idle(int cpu, ktime_t now)
+{
+	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+	update_ts_time_stats(ts, now);
 	ts->idle_active = 0;
 
 	sched_clock_idle_wakeup_event(0);
@@ -165,14 +176,12 @@ static void tick_nohz_stop_idle(int cpu, ktime_t now)
 
 static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
 {
-	ktime_t now, delta;
+	ktime_t now;
 
 	now = ktime_get();
-	if (ts->idle_active) {
-		delta = ktime_sub(now, ts->idle_entrytime);
-		ts->idle_lastupdate = now;
-		ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-	}
+
+	update_ts_time_stats(ts, now);
+
 	ts->idle_entrytime = now;
 	ts->idle_active = 1;
 	sched_clock_idle_sleep_event();
-- 
1.6.2.5

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