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@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082245.163e67ed@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 358822e..59d8762 100644 (file)
--- 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();