[PATCH tip/core/rcu 05/17] rcu: remove redundant ACCESS_ONCE() from tick_do_timer_cpu

From: Paul E. McKenney
Date: Mon Jul 07 2014 - 18:39:31 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

In kernels built with CONFIG_NO_HZ_FULL, tick_do_timer_cpu is constant
once boot completes. Thus, there is no need to wrap it in ACCESS_ONCE()
in code that is built only when CONFIG_NO_HZ_FULL. This commit therefore
removes the redundant ACCESS_ONCE().

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree_plugin.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 02ac0fb186b8..5da9f9b3abc9 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2844,7 +2844,7 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
static void rcu_bind_gp_kthread(void)
{
#ifdef CONFIG_NO_HZ_FULL
- int cpu = ACCESS_ONCE(tick_do_timer_cpu);
+ int cpu = tick_do_timer_cpu;

if (cpu < 0 || cpu >= nr_cpu_ids)
return;
--
1.8.1.5

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