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>

diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index b96559c..4b8474c 100644 (file)
--- 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);