commit cf3a9c4842b1e097dbe0854933c471d43dd24f69
author Paul E. McKenney <paul.mckenney@linaro.org> Tue May 29 14:56:46 2012 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> Mon Jul 02 12:33:23 2012 -0700
tree 5b2737cade79c491ba46cd642c01cc165118d723
parent cfed0a85dad921c683e9c0d25b072bcc5745ede0

rcu: Increase rcu_barrier() concurrency

The traditional rcu_barrier() implementation has serialized all requests,
regardless of RCU flavor, and also does not coalesce concurrent requests.
In the past, this has been good and sufficient.

However, systems are getting larger and use of rcu_barrier() has been
increasing.  This commit therefore introduces a counter-based scheme
that allows _rcu_barrier() calls for the same flavor of RCU to take
advantage of each others' work.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>