[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-Id: <20220418225642.3945539-3-paulmck@kernel.org>
Date: Mon, 18 Apr 2022 15:56:40 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, kernel-team@...com,
rostedt@...dmis.org, Frederic Weisbecker <frederic@...nel.org>,
Neeraj Upadhyay <quic_neeraju@...cinc.com>,
Uladzislau Rezki <uladzislau.rezki@...y.com>,
Joel Fernandes <joel@...lfernandes.org>,
Boqun Feng <boqun.feng@...il.com>,
"Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH rcu 3/5] rcu: Assume rcu_init() is called before smp
From: Frederic Weisbecker <frederic@...nel.org>
The rcu_init() function is called way before SMP is initialized and
therefore only the boot CPU should be online at this stage.
Simplify the boot per-cpu initialization accordingly.
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Neeraj Upadhyay <quic_neeraju@...cinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@...y.com>
Cc: Joel Fernandes <joel@...lfernandes.org>
Cc: Boqun Feng <boqun.feng@...il.com>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
kernel/rcu/tree.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a4b8189455d5..e6a9e5744e45 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4782,7 +4782,7 @@ static void __init kfree_rcu_batch_init(void)
void __init rcu_init(void)
{
- int cpu;
+ int cpu = smp_processor_id();
rcu_early_boot_tests();
@@ -4802,11 +4802,10 @@ void __init rcu_init(void)
* or the scheduler are operational.
*/
pm_notifier(rcu_pm_notify, 0);
- for_each_online_cpu(cpu) {
- rcutree_prepare_cpu(cpu);
- rcu_cpu_starting(cpu);
- rcutree_online_cpu(cpu);
- }
+ WARN_ON(num_online_cpus() > 1); // Only one CPU this early in boot.
+ rcutree_prepare_cpu(cpu);
+ rcu_cpu_starting(cpu);
+ rcutree_online_cpu(cpu);
/* Create workqueue for Tree SRCU and for expedited GPs. */
rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_MEM_RECLAIM, 0);
--
2.31.1.189.g2e36527f23
Powered by blists - more mailing lists