diff mbox series

[4/6] rcu: Remove full memory barrier on boot time eqs sanity check

Message ID 20240604222652.2370998-4-paulmck@kernel.org (mailing list archive)
State Accepted
Commit d43a302fc08a598a164614fe42bea065dba9b648
Headers show
Series Grace-period memory-barrier adjustments for v6.11 | expand

Commit Message

Paul E. McKenney June 4, 2024, 10:26 p.m. UTC 
From: Frederic Weisbecker <frederic@kernel.org>

When the boot CPU initializes the per-CPU data on behalf of all possible
CPUs, a sanity check is performed on each of them to make sure none is
initialized in an extended quiescent state.

This check involves a full memory barrier which is useless at this early
boot stage.

Do a plain access instead.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1a6ef9c5c949e..9fa6d2b557d6c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4772,7 +4772,7 @@  rcu_boot_init_percpu_data(int cpu)
 	rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
 	INIT_WORK(&rdp->strict_work, strict_work_handler);
 	WARN_ON_ONCE(ct->dynticks_nesting != 1);
-	WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu)));
+	WARN_ON_ONCE(rcu_dynticks_in_eqs(ct_dynticks_cpu(cpu)));
 	rdp->barrier_seq_snap = rcu_state.barrier_sequence;
 	rdp->rcu_ofl_gp_seq = rcu_state.gp_seq;
 	rdp->rcu_ofl_gp_state = RCU_GP_CLEANED;