sched/clock: Make local_clock()/cpu_clock() inline

The local_clock/cpu_clock functions were changed to prevent a double
identical test with sched_clock_cpu() when HAVE_UNSTABLE_SCHED_CLOCK
is set. That resulted in one line functions.

As these functions are in all the cases one line functions and in the
hot path, it is useful to specify them as static inline in order to
give a strong hint to the compiler.

After verification, it appears the compiler does not inline them
without this hint. Change those functions to static inline.

sched_clock_cpu() is called via the inlined local_clock()/cpu_clock()
functions from sched.h. So any module code including sched.h will
reference sched_clock_cpu(). Thus it must be exported with the
EXPORT_SYMBOL_GPL macro.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1460385514-14700-2-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 41 deletions

diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 30c4b202f0ba..e85a725e5c34 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -318,6 +318,7 @@ u64 sched_clock_cpu(int cpu)
 
 	return clock;
 }
+EXPORT_SYMBOL_GPL(sched_clock_cpu);
 
 void sched_clock_tick(void)
 {
@@ -363,33 +364,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
 }
 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
 
-/*
- * As outlined at the top, provides a fast, high resolution, nanosecond
- * time source that is monotonic per cpu argument and has bounded drift
- * between cpus.
- *
- * ######################### BIG FAT WARNING ##########################
- * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
- * # go backwards !!                                                  #
- * ####################################################################
- */
-u64 cpu_clock(int cpu)
-{
-	return sched_clock_cpu(cpu);
-}
-
-/*
- * Similar to cpu_clock() for the current cpu. Time will only be observed
- * to be monotonic if care is taken to only compare timestampt taken on the
- * same CPU.
- *
- * See cpu_clock().
- */
-u64 local_clock(void)
-{
-	return sched_clock_cpu(raw_smp_processor_id());
-}
-
 #else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
 
 void sched_clock_init(void)
@@ -404,22 +378,8 @@ u64 sched_clock_cpu(int cpu)
 
 	return sched_clock();
 }
-
-u64 cpu_clock(int cpu)
-{
-	return sched_clock();
-}
-
-u64 local_clock(void)
-{
-	return sched_clock();
-}
-
 #endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
 
-EXPORT_SYMBOL_GPL(cpu_clock);
-EXPORT_SYMBOL_GPL(local_clock);
-
 /*
  * Running clock - returns the time that has elapsed while a guest has been
  * running.