sched_clock: Add local_clock() API and improve documentation

For people who otherwise get to write: cpu_clock(smp_processor_id()),
there is now: local_clock().

Also, as per suggestion from Andrew, provide some documentation on
the various clock interfaces, and minimize the unsigned long long vs
u64 mess.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jens Axboe <jaxboe@fusionio.com>
LKML-Reference: <1275052414.1645.52.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 2 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 6535ac8bc6a5..2e2726d790b9 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -239,8 +239,7 @@ static unsigned long
 rcu_random(struct rcu_random_state *rrsp)
 {
         if (--rrsp->rrs_count < 0) {
-                rrsp->rrs_state +=
-                        (unsigned long)cpu_clock(raw_smp_processor_id());
+                rrsp->rrs_state += (unsigned long)local_clock();
                 rrsp->rrs_count = RCU_RANDOM_REFRESH;
         }
         rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;