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From: Frederic Weisbecker <frederic@kernel.org>
To: "Paul E . McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Neeraj Upadhyay <neeraju@codeaurora.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Stable <stable@vger.kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>
Subject: [PATCH 08/16] rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible
Date: Thu, 28 Jan 2021 18:12:14 +0100	[thread overview]
Message-ID: <20210128171222.131380-9-frederic@kernel.org> (raw)
In-Reply-To: <20210128171222.131380-1-frederic@kernel.org>

Those tracing calls don't need to be under the nocb lock. Move them
outside.

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>
---
 kernel/rcu/tree_plugin.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 86c3bcceede6..8c5fea58ee80 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1700,9 +1700,9 @@ 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;
 	}
 
@@ -1950,9 +1950,9 @@ 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.
@@ -1987,8 +1987,8 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 					   TPS("WakeOvfIsDeferred"));
 		rcu_nocb_unlock_irqrestore(rdp, flags);
 	} else {
+		rcu_nocb_unlock_irqrestore(rdp, flags);
 		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
-		rcu_nocb_unlock_irqrestore(rdp, flags);
 	}
 	return;
 }
-- 
2.25.1


  parent reply	other threads:[~2021-01-28 17:42 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-28 17:12 [PATCH 00/16] rcu/nocb updates Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 01/16] rcu/nocb: Fix potential missed nocb_timer rearm Frederic Weisbecker
     [not found]   ` <20210128184834.GP2743@paulmck-ThinkPad-P72>
2021-01-28 21:23     ` Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 02/16] rcu/nocb: Comment the reason behind BH disablement on batch processing Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 03/16] rcu/nocb: Forbid NOCB toggling on offline CPUs Frederic Weisbecker
2021-01-28 19:52   ` Paul E. McKenney
2021-01-28 17:12 ` [PATCH 04/16] rcu/nocb: Only (re-)initialize segcblist when needed on CPU up Frederic Weisbecker
     [not found]   ` <20210128191228.GQ2743@paulmck-ThinkPad-P72>
2021-01-28 21:34     ` Frederic Weisbecker
2021-01-28 21:45       ` Paul E. McKenney
2021-01-29  0:26         ` Paul E. McKenney
2021-01-28 17:12 ` [PATCH 05/16] rcu/nocb: Disable bypass when CPU isn't completely offloaded Frederic Weisbecker
2021-01-28 21:31   ` Paul E. McKenney
2021-01-28 22:25     ` Frederic Weisbecker
2021-01-29  0:19       ` Paul E. McKenney
2021-01-28 17:12 ` [PATCH 06/16] rcu/nocb: Avoid confusing double write of rdp->nocb_cb_sleep Frederic Weisbecker
2021-01-28 21:42   ` Paul E. McKenney
2021-01-28 17:12 ` [PATCH 07/16] rcu/nocb: Rename nocb_gp_update_state to nocb_gp_update_state_deoffloading Frederic Weisbecker
2021-01-29  0:49   ` Paul E. McKenney
2021-01-28 17:12 ` Frederic Weisbecker [this message]
2021-01-29  0:51   ` [PATCH 08/16] rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible Paul E. McKenney
2021-01-28 17:12 ` [PATCH 09/16] rcu/nocb: Merge nocb_timer to the rdp leader Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 10/16] rcu/nocb: Directly call __wake_nocb_gp() from bypass timer Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 11/16] rcu/nocb: Allow de-offloading rdp leader Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 12/16] rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 13/16] rcu/nocb: Delete bypass_timer " Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 14/16] rcu/nocb: Only cancel nocb timer if not polling Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 15/16] rcu/nocb: Prepare for finegrained deferred wakeup Frederic Weisbecker
2021-01-28 17:12 ` [PATCH 16/16] rcu/nocb: Unify timers Frederic Weisbecker

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