Document Linux's circular buffering capabilities

Document the circular buffering capabilities available in Linux.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Randy Dunlap <rdunlap@xenotime.net>
Reviewed-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt
index 7f5809e..631ad2f 100644
--- a/Documentation/memory-barriers.txt
+++ b/Documentation/memory-barriers.txt
@@ -3,6 +3,7 @@
 			 ============================
 
 By: David Howells <dhowells@redhat.com>
+    Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 
 Contents:
 
@@ -60,6 +61,10 @@
 
      - And then there's the Alpha.
 
+ (*) Example uses.
+
+     - Circular buffers.
+
  (*) References.
 
 
@@ -2226,6 +2231,21 @@
 See the subsection on "Cache Coherency" above.
 
 
+============
+EXAMPLE USES
+============
+
+CIRCULAR BUFFERS
+----------------
+
+Memory barriers can be used to implement circular buffering without the need
+of a lock to serialise the producer with the consumer.  See:
+
+	Documentation/circular-buffers.txt
+
+for details.
+
+
 ==========
 REFERENCES
 ==========