this_cpu: Use this_cpu operations in RCU

RCU does not do dynamic allocations but it increments per cpu variables
a lot. These instructions results in a move to a register and then back
to memory. This patch will make it use the inc/dec instructions on x86
that do not need a register.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 233768f21f97..178967b6434e 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -731,13 +731,13 @@ static void rcu_torture_timer(unsigned long unused)
                 /* Should not happen, but... */
                 pipe_count = RCU_TORTURE_PIPE_LEN;
         }
-        ++__get_cpu_var(rcu_torture_count)[pipe_count];
+        __this_cpu_inc(per_cpu_var(rcu_torture_count)[pipe_count]);
         completed = cur_ops->completed() - completed;
         if (completed > RCU_TORTURE_PIPE_LEN) {
                 /* Should not happen, but... */
                 completed = RCU_TORTURE_PIPE_LEN;
         }
-        ++__get_cpu_var(rcu_torture_batch)[completed];
+        __this_cpu_inc(per_cpu_var(rcu_torture_batch)[completed]);
         preempt_enable();
         cur_ops->readunlock(idx);
 }
@@ -786,13 +786,13 @@ rcu_torture_reader(void *arg)
                         /* Should not happen, but... */
                         pipe_count = RCU_TORTURE_PIPE_LEN;
                 }
-                ++__get_cpu_var(rcu_torture_count)[pipe_count];
+                __this_cpu_inc(per_cpu_var(rcu_torture_count)[pipe_count]);
                 completed = cur_ops->completed() - completed;
                 if (completed > RCU_TORTURE_PIPE_LEN) {
                         /* Should not happen, but... */
                         completed = RCU_TORTURE_PIPE_LEN;
                 }
-                ++__get_cpu_var(rcu_torture_batch)[completed];
+                __this_cpu_inc(per_cpu_var(rcu_torture_batch)[completed]);
                 preempt_enable();
                 cur_ops->readunlock(idx);
                 schedule();