sched: eliminate scd->prev_raw

eliminate prev_raw and use tick_raw instead.

It's enough to base the current time on the scheduler tick timestamp
alone - the monotonicity and maximum checks will prevent any damage.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>

1 files changed, 1 insertions, 5 deletions

diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index b96559cb96a..4b8474c966d 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -53,7 +53,6 @@ struct sched_clock_data {
         raw_spinlock_t          lock;
 
         unsigned long           tick_jiffies;
-        u64                     prev_raw;
         u64                     tick_raw;
         u64                     tick_gtod;
         u64                     clock;
@@ -84,7 +83,6 @@ void sched_clock_init(void)
 
                 scd->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
                 scd->tick_jiffies = now_jiffies;
-                scd->prev_raw = 0;
                 scd->tick_raw = 0;
                 scd->tick_gtod = ktime_now;
                 scd->clock = ktime_now;
@@ -105,7 +103,7 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now)
         long delta_jiffies = now_jiffies - scd->tick_jiffies;
         u64 clock = scd->clock;
         u64 min_clock, max_clock;
-        s64 delta = now - scd->prev_raw;
+        s64 delta = now - scd->tick_raw;
 
         WARN_ON_ONCE(!irqs_disabled());
         min_clock = scd->tick_gtod + delta_jiffies * TICK_NSEC;
@@ -130,7 +128,6 @@ static void __update_sched_clock(struct sched_clock_data *scd, u64 now)
         if (unlikely(clock < min_clock))
                 clock = min_clock;
 
-        scd->prev_raw = now;
         scd->tick_jiffies = now_jiffies;
         scd->clock = clock;
 }
@@ -234,7 +231,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
          * rq clock:
          */
         __raw_spin_lock(&scd->lock);
-        scd->prev_raw = now;
         scd->clock += delta_ns;
         __raw_spin_unlock(&scd->lock);