[PATCH tip/core/rcu 0/3] Documentation and rcutorture changes for 3.9

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

Hello!

The following are changes to documentation and rcutorture:

1.	Export trace_clock_local() in order to allow rcutorture event
	tracing to emit the time of the beginning of the RCU read-side
	critical section at the point where a failure is detected.
2.	Reduce rcutorture's read-side tracing to include only failures,
	thus cutting the number of events down to something reasonable
	(normally zero, in fact!).
3.	Add atomic_xchg() to the list of atomic operations and memory
	barriers, courtesy of Richard Braun.

							Thanx, Paul


 Documentation/atomic_ops.txt      |    2 ++
 Documentation/memory-barriers.txt |    1 +
 include/linux/rcupdate.h          |   13 ++++++++++---
 include/trace/events/rcu.h        |   19 ++++++++++++++-----
 kernel/rcupdate.c                 |    9 ++++++---
 kernel/rcutorture.c               |   31 ++++++++++++++++++++++++-------
 kernel/trace/trace_clock.c        |    1 +
 7 files changed, 58 insertions(+), 18 deletions(-)