rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible

Those tracing calls don't need to be under ->nocb_lock.  This commit
therefore moves them outside of that lock.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index b08564b..9846c8a 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1703,9 +1703,9 @@ static bool wake_nocb_gp(struct rcu_data *rdp, bool force,
 
        lockdep_assert_held(&rdp->nocb_lock);
        if (!READ_ONCE(rdp_gp->nocb_gp_kthread)) {
+               rcu_nocb_unlock_irqrestore(rdp, flags);
                trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
                                    TPS("AlreadyAwake"));
-               rcu_nocb_unlock_irqrestore(rdp, flags);
                return false;
        }
 
@@ -1955,9 +1955,9 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
        // If we are being polled or there is no kthread, just leave.
        t = READ_ONCE(rdp->nocb_gp_kthread);
        if (rcu_nocb_poll || !t) {
+               rcu_nocb_unlock_irqrestore(rdp, flags);
                trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
                                    TPS("WakeNotPoll"));
-               rcu_nocb_unlock_irqrestore(rdp, flags);
                return;
        }
        // Need to actually to a wakeup.
@@ -1992,8 +1992,8 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
                                           TPS("WakeOvfIsDeferred"));
                rcu_nocb_unlock_irqrestore(rdp, flags);
        } else {
-               trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
                rcu_nocb_unlock_irqrestore(rdp, flags);
+               trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
        }
        return;
 }