[PATCH v2 5/8] sched: Eliminate the ts->idle_lastupdate field

From: Arjan van de Ven
Date: Sun May 09 2010 - 11:25:32 EST


From: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
---

include/linux/tick.h | 1 -
kernel/time/tick-sched.c | 5 +----
2 files changed, 1 insertion(+), 5 deletions(-)

diff -puN include/linux/tick.h~sched-eliminate-the-ts-idle_lastupdate-field include/linux/tick.h
--- a/include/linux/tick.h~sched-eliminate-the-ts-idle_lastupdate-field
+++ a/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 -puN kernel/time/tick-sched.c~sched-eliminate-the-ts-idle_lastupdate-field kernel/time/tick-sched.c
--- a/kernel/time/tick-sched.c~sched-eliminate-the-ts-idle_lastupdate-field
+++ a/kernel/time/tick-sched.c
@@ -158,16 +158,13 @@ update_ts_time_stats(struct tick_sched *
{
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);

}
_
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