sched_clock: cleanups

- remove superfluous checks in __update_sched_clock()
- skip sched_clock_tick() for sched_clock_stable
- reinstate the simple !HAVE_UNSTABLE_SCHED_CLOCK code to please the bloatwatch

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 20 insertions, 11 deletions

diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index a755d023805a..390f33234bd0 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -44,9 +44,6 @@ static __read_mostly int sched_clock_running;
 
 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
 __read_mostly int sched_clock_stable;
-#else
-static const int sched_clock_stable = 1;
-#endif
 
 struct sched_clock_data {
         /*
@@ -115,14 +112,9 @@ static u64 __update_sched_clock(struct sched_clock_data *scd, u64 now)
         s64 delta = now - scd->tick_raw;
         u64 clock, min_clock, max_clock;
 
-        WARN_ON_ONCE(!irqs_disabled());
-
         if (unlikely(delta < 0))
                 delta = 0;
 
-        if (unlikely(!sched_clock_running))
-                return 0ull;
-
         /*
          * scd->clock = clamp(scd->tick_gtod + delta,
          *                    max(scd->tick_gtod, scd->clock),
@@ -201,18 +193,20 @@ u64 sched_clock_cpu(int cpu)
         return clock;
 }
 
-#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-
 void sched_clock_tick(void)
 {
-        struct sched_clock_data *scd = this_scd();
+        struct sched_clock_data *scd;
         u64 now, now_gtod;
 
+        if (sched_clock_stable)
+                return;
+
         if (unlikely(!sched_clock_running))
                 return;
 
         WARN_ON_ONCE(!irqs_disabled());
 
+        scd = this_scd();
         now_gtod = ktime_to_ns(ktime_get());
         now = sched_clock();
 
@@ -245,6 +239,21 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
 }
 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
 
+#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
+
+void sched_clock_init(void)
+{
+        sched_clock_running = 1;
+}
+
+u64 sched_clock_cpu(int cpu)
+{
+        if (unlikely(!sched_clock_running))
+                return 0;
+
+        return sched_clock();
+}
+
 #endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
 
 unsigned long long cpu_clock(int cpu)