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authorLi Zefan <lizefan@huawei.com>2013-03-29 14:37:43 +0800
committerIngo Molnar <mingo@kernel.org>2013-04-10 13:54:18 +0200
commit5f40d804325e925409907e29f46ecb012090b6c2 (patch)
tree28cd9dd3f0a7ed059d1167ba8c77e725445e9986 /kernel/sched
parent543bc0e76e6bb84300eaf9833edc5a481f788678 (diff)
sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field()
This is a micro optimazation for a hot path. - We don't need to check if @ca returned from task_ca() is NULL. - We don't need to check if @ca returned from parent_ca() is NULL. Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/515536B7.6060602@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/cpuacct.c4
-rw-r--r--kernel/sched/cpuacct.h5
2 files changed, 7 insertions, 2 deletions
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index b2aaaba16d46..071ae8d08181 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -237,10 +237,10 @@ void cpuacct_account_field(struct task_struct *p, int index, u64 val)
rcu_read_lock();
ca = task_ca(p);
- while (ca && (ca != &root_cpuacct)) {
+ while (ca != &root_cpuacct) {
kcpustat = this_cpu_ptr(ca->cpustat);
kcpustat->cpustat[index] += val;
- ca = parent_ca(ca);
+ ca = __parent_ca(ca);
}
rcu_read_unlock();
}
diff --git a/kernel/sched/cpuacct.h b/kernel/sched/cpuacct.h
index 45c168207fcc..b2f79ad1e524 100644
--- a/kernel/sched/cpuacct.h
+++ b/kernel/sched/cpuacct.h
@@ -34,6 +34,11 @@ static inline struct cpuacct *task_ca(struct task_struct *tsk)
struct cpuacct, css);
}
+static inline struct cpuacct *__parent_ca(struct cpuacct *ca)
+{
+ return cgroup_ca(ca->css.cgroup->parent);
+}
+
static inline struct cpuacct *parent_ca(struct cpuacct *ca)
{
if (!ca->css.cgroup->parent)