Commit-ID: 11bbb235c26f93b7c69e441452e44adbf6ed6996
Gitweb: http://git.kernel.org/tip/11bbb235c26f93b7c69e441452e44adbf6ed6996
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 4 Sep 2014 12:21:41 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 3 Nov 2014 19:20:03 -0800
rcu: Use DEFINE_PER_CPU_SHARED_ALIGNED for rcu_data
The rcu_data per-CPU variable has a number of fields that are atomically
manipulated, potentially by any CPU. This situation can result in false
sharing with per-CPU variables that have the misfortune of being allocated
adjacent to rcu_data in memory. This commit therefore changes the
DEFINE_PER_CPU() to DEFINE_PER_CPU_SHARED_ALIGNED() in order to avoid
this false sharing.
Reported-by: Christoph Lameter <cl@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Christoph Lameter <cl@xxxxxxxxx>
Reviewed-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
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 c0673c5..ab6fcfb 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -105,7 +105,7 @@ struct rcu_state sname##_state = { \
.name = RCU_STATE_NAME(sname), \
.abbr = sabbr, \
}; \
-DEFINE_PER_CPU(struct rcu_data, sname##_data)
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, sname##_data)
RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched);
RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh);
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|