[PATCH tip/core/rcu 12/20] rcu: Remove event tracing from rcu_cpu_notify(), used by offline CPUs

Paul E. McKenney
2015-03-03T17:52:31Z

Offline CPUs cannot safely invoke trace events, but such CPUs do execute
within rcu_cpu_notify(). Therefore, this commit removes the trace events
from rcu_cpu_notify(). These trace events are for utilization, against
which rcu_cpu_notify() execution time should be negligible.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/tree.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index b42001fd55fb..a7151d26b940 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3629,7 +3629,6 @@ static int rcu_cpu_notify(struct notifier_block *self,
struct rcu_node *rnp = rdp->mynode;
struct rcu_state *rsp;

- trace_rcu_utilization(TPS("Start CPU hotplug"));
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
@@ -3661,7 +3660,6 @@ static int rcu_cpu_notify(struct notifier_block *self,
default:
break;
}
- trace_rcu_utilization(TPS("End CPU hotplug"));
return NOTIFY_OK;
}

--
1.8.1.5