doc: Use rcu_barrier() to rate-limit RCU callbacks

The checklist.rst document advises periodic synchronize_rcu() invocations
to prevent callback flooding.  However, rcu_barrier() is often a better
choice.  This commit therefore adds words to this effect.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst
index 2db206f..178ca75 100644 (file)
--- a/Documentation/RCU/checklist.rst
+++ b/Documentation/RCU/checklist.rst
@@ -305,7 +305,8 @@ over a rather long period of time, but improvements are always welcome!
                the machine.
 
        d.      Periodically invoke synchronize_rcu(), permitting a limited
-               number of updates per grace period.
+               number of updates per grace period.  Better yet, periodically
+               invoke rcu_barrier() to wait for all outstanding callbacks.
 
        The same cautions apply to call_srcu() and kfree_rcu().