Commit 999c2863 authored Jan 31, 2015 by Paul E. McKenney

rcu: Remove event tracing from rcu_cpu_notify(), used by offline CPUs

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>

parent b6505dea

kernel/rcu/tree.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}