sched: Eliminate the ts->idle_lastupdate field

Now that the only user of ts->idle_lastupdate is
update_ts_time_stats(), the entire field can be eliminated.

In update_ts_time_stats(), idle_lastupdate is first set to
"now", and a few lines later, the only user is an if() statement
that assigns a variable either to "now" or to
ts->idle_lastupdate, which has the value of "now" at that point.

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: <20100509082439.2fab0b4f@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 1 insertions, 5 deletions

diff --git a/include/linux/tick.h b/include/linux/tick.h
index d2ae79e21be3..0343eed40619 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -60,7 +60,6 @@ struct tick_sched {
         ktime_t                         idle_waketime;
         ktime_t                         idle_exittime;
         ktime_t                         idle_sleeptime;
-        ktime_t                         idle_lastupdate;
         ktime_t                         sleep_length;
         unsigned long                   last_jiffies;
         unsigned long                   next_jiffies;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index e86e1c6674d1..50953f4c42b2 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -158,16 +158,13 @@ update_ts_time_stats(struct tick_sched *ts, ktime_t now, u64 *last_update_time)
 {
         ktime_t delta;
 
-        ts->idle_lastupdate = now;
         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 (ts->idle_active && last_update_time)
-                *last_update_time = ktime_to_us(ts->idle_lastupdate);
-        else
+        if (last_update_time)
                 *last_update_time = ktime_to_us(now);
 
 }