sched: Eliminate the ts->idle_lastupdate field

[pandora-kernel.git] / kernel / time / tick-sched.c

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f25735a..50953f4 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -150,14 +150,30 @@ static void tick_nohz_update_jiffies(ktime_t now)
        touch_softlockup_watchdog();
 }
 
+/*
+ * Updates the per cpu time idle statistics counters
+ */
+static void
+update_ts_time_stats(struct tick_sched *ts, ktime_t now, u64 *last_update_time)
+{
+       ktime_t delta;
+
+       if (ts->idle_active) {
+               delta = ktime_sub(now, ts->idle_entrytime);
+               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+               ts->idle_entrytime = now;
+       }
+
+       if (last_update_time)
+               *last_update_time = ktime_to_us(now);
+
+}
+
 static void tick_nohz_stop_idle(int cpu, 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);
+       update_ts_time_stats(ts, now, NULL);
        ts->idle_active = 0;
 
        sched_clock_idle_wakeup_event(0);
@@ -165,20 +181,32 @@ 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, NULL);
+
        ts->idle_entrytime = now;
        ts->idle_active = 1;
        sched_clock_idle_sleep_event();
        return now;
 }
 
+/**
+ * get_cpu_idle_time_us - get the total idle time of a cpu
+ * @cpu: CPU number to query
+ * @last_update_time: variable to store update time in
+ *
+ * Return the cummulative idle time (since boot) for a given
+ * CPU, in microseconds. The idle time returned includes
+ * the iowait time (unlike what "top" and co report).
+ *
+ * This time is measured via accounting rather than sampling,
+ * and is as accurate as ktime_get() is.
+ *
+ * This function returns -1 if NOHZ is not enabled.
+ */
 u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
        struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
@@ -186,10 +214,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
        if (!tick_nohz_enabled)
                return -1;
 
-       if (ts->idle_active)
-               *last_update_time = ktime_to_us(ts->idle_lastupdate);
-       else
-               *last_update_time = ktime_to_us(ktime_get());
+       update_ts_time_stats(ts, ktime_get(), last_update_time);
 
        return ktime_to_us(ts->idle_sleeptime);
 }