[PATCH tip/core/rcu 0/6] rcu: fix synchronize_rcu_expedited(), update docs, improve perf

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

This patchset contains a bug fix, a performance improvement, and
documentation updates:

o	Update Documentation/RCU/trace.txt to reflect recent changes
	(including the removal of rcupreempt.c).

o	Fix to the severe performance problem with excessive IPIs and
	lock contention in presence of very large (but legal) numbers
	of RCU callbacks (reported by Nick Piggin).

o	Stopgap fix for a bug in TREE_PREEMPT_RCU's implementation of
	synchronize_rcu_expedited().  This fix is correct, but no faster
	than synchronize_rcu().

o	Add exports for the updated synchronize_rcu_expedited()
	implementation, which moved from a static inline in
	include/linux/rcupdate.h to a separately compiled function
	in kernel/rcutree_plugin.h.

o	Add the new rnp->blocked_tasks field to the rcuhier trace file
	in debugfs.

o	Update the Documentation/RCU/trace.txt documentation to include
	the rnp->blocked_tasks tracing.

I believe that this is 2.6.32 material.

 Documentation/RCU/trace.txt   |   22 ++-
 b/Documentation/RCU/trace.txt |  232 +++++-------------------------------------
 b/include/linux/rcutree.h     |    6 -
 b/kernel/rcutree.c            |   29 ++++-
 b/kernel/rcutree.h            |    5 
 b/kernel/rcutree_plugin.h     |   20 +++
 b/kernel/rcutree_trace.c      |    8 -
 kernel/rcutree_plugin.h       |    3 
 8 files changed, 103 insertions(+), 222 deletions(-)