From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 4/6] rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load
Date: Mon, 17 Jul 2023 11:03:15 -0700 [thread overview]
Message-ID: <20230717180317.1097590-4-paulmck@kernel.org> (raw)
In-Reply-To: <6127192c-da9b-4599-9738-6e8f92e6c75c@paulmck-laptop>
The rcu_request_urgent_qs_task() function does a cross-CPU store
to ->rcu_urgent_qs, so this commit therefore marks the load in
__rcu_irq_enter_check_tick() with READ_ONCE().
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index fae9b4e29c93..aec07f2ec638 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -632,7 +632,7 @@ void __rcu_irq_enter_check_tick(void)
// prevents self-deadlock. So we can safely recheck under the lock.
// Note that the nohz_full state currently cannot change.
raw_spin_lock_rcu_node(rdp->mynode);
- if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {
+ if (READ_ONCE(rdp->rcu_urgent_qs) && !rdp->rcu_forced_tick) {
// A nohz_full CPU is in the kernel and RCU needs a
// quiescent state. Turn on the tick!
WRITE_ONCE(rdp->rcu_forced_tick, true);
--
2.40.1
next prev parent reply other threads:[~2023-07-17 18:03 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 18:03 [PATCH rcu 0/6] Miscellaneous fixes for v6.6 Paul E. McKenney
2023-07-17 18:03 ` [PATCH rcu 1/6] rcu: Update synchronize_rcu_mult() comment for call_rcu_hurry() Paul E. McKenney
2023-07-18 12:59 ` Joel Fernandes
2023-07-17 18:03 ` [PATCH rcu 2/6] rcu: Clarify rcu_is_watching() kernel-doc comment Paul E. McKenney
2023-07-18 12:52 ` Joel Fernandes
2023-07-18 18:12 ` Paul E. McKenney
2023-07-19 1:56 ` Joel Fernandes
2023-07-19 20:38 ` Paul E. McKenney
2023-07-17 18:03 ` [PATCH rcu 3/6] srcu,notifier: Remove #ifdefs in favor of SRCU Tiny srcu_usage Paul E. McKenney
2023-07-17 18:09 ` Linus Torvalds
2023-07-17 18:16 ` Paul E. McKenney
2023-07-17 18:03 ` Paul E. McKenney [this message]
2023-07-18 12:58 ` [PATCH rcu 4/6] rcu: Mark __rcu_irq_enter_check_tick() ->rcu_urgent_qs load Joel Fernandes
2023-07-17 18:03 ` [PATCH rcu 5/6] rcu: Make the rcu_nocb_poll boot parameter usable via boot config Paul E. McKenney
2023-07-18 13:46 ` Joel Fernandes
2023-07-17 18:03 ` [PATCH rcu 6/6] rcu: Use WRITE_ONCE() for assignments to ->next for rculist_nulls Paul E. McKenney
2023-07-18 13:49 ` Joel Fernandes
2023-07-18 14:48 ` Alan Huang
2023-07-18 18:32 ` Paul E. McKenney
2023-07-19 1:48 ` Joel Fernandes
2023-07-19 18:20 ` Paul E. McKenney
2023-07-19 19:17 ` Alan Huang
2023-07-19 20:02 ` Paul E. McKenney
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