[PATCH] rcu: keep rcu callback event counter

This makes call_rcu() keep track of how many events there are on the RCU
list, and cause a reschedule event when the list gets too long.

This helps keep RCU event lists down.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 4e65eb4..70191a5 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -94,6 +94,7 @@
 	long  	       	batch;           /* Batch # for current RCU batch */
 	struct rcu_head *nxtlist;
 	struct rcu_head **nxttail;
+	long            count; /* # of queued items */
 	struct rcu_head *curlist;
 	struct rcu_head **curtail;
 	struct rcu_head *donelist;