rcu: Trace expedited GP delays due to transitioning CPUs

If a CPU is transitioning to or from offline state, an expedited
grace period may undergo a timed wait.  This timed wait can unduly
delay grace periods, so this commit adds a trace statement to make
it visible.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index e56a618f2a59..d8c33298c153 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -181,6 +181,7 @@ TRACE_EVENT(rcu_grace_period_init,
  *      "start": Started a real expedited grace period.
  *      "reset": Started resetting the tree
  *      "select": Started selecting the CPUs to wait on.
+ *      "selectofl": Selected CPU partially offline.
  *      "startwait": Started waiting on selected CPUs.
  *      "end": Ended a real expedited grace period.
  *      "endwake": Woke piggybackers up.