rcu: Augment rcu_batch_end tracing for idle and callback state

The current rcu_batch_end event trace records only the name of the RCU
flavor and the total number of callbacks that remain queued on the
current CPU.  This is insufficient for testing and tuning the new
dyntick-idle RCU_FAST_NO_HZ code, so this commit adds idle state along
with whether or not any of the callbacks that were ready to invoke
at the beginning of rcu_do_batch() are still queued.

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

1 files changed, 6 insertions, 2 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 2b2e1a996a65..6c4a6722abfd 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1373,7 +1373,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
 	/* If no callbacks are ready, just return.*/
 	if (!cpu_has_callbacks_ready_to_invoke(rdp)) {
 		trace_rcu_batch_start(rsp->name, 0, 0);
-		trace_rcu_batch_end(rsp->name, 0);
+		trace_rcu_batch_end(rsp->name, 0, !!ACCESS_ONCE(rdp->nxtlist),
+				    need_resched(), is_idle_task(current),
+				    rcu_is_callbacks_kthread());
 		return;
 	}
 
@@ -1409,7 +1411,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
 	}
 
 	local_irq_save(flags);
-	trace_rcu_batch_end(rsp->name, count);
+	trace_rcu_batch_end(rsp->name, count, !!list, need_resched(),
+			    is_idle_task(current),
+			    rcu_is_callbacks_kthread());
 
 	/* Update count, and requeue any remaining callbacks. */
 	rdp->qlen -= count;