sched/cputime: Use this_cpu_add() in task_group_account_field()
authorChristoph Lameter <cl@gentwo.org>
Wed, 7 Aug 2013 15:38:24 +0000 (15:38 +0000)
committerIngo Molnar <mingo@kernel.org>
Fri, 16 Aug 2013 15:44:29 +0000 (17:44 +0200)
Use of a this_cpu() operation reduces the number of instructions used
for accounting (account_user_time()) and frees up some registers. This is in
the scheduler tick hotpath.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/00000140596dd165-338ff7f5-893b-4fec-b251-aaac5557239e-000000@email.amazonses.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/sched/cputime.c

index a7959e0..e89ccef 100644 (file)
@@ -121,7 +121,7 @@ static inline void task_group_account_field(struct task_struct *p, int index,
         * is the only cgroup, then nothing else should be necessary.
         *
         */
-       __get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
+       __this_cpu_add(kernel_cpustat.cpustat[index], tmp);
 
        cpuacct_account_field(p, index, tmp);
 }