The whole of ttwu_stat() is guarded by a single schedstat_enabled(), there is absolutely no point in then issuing another static_branch for every single schedstat_inc() in there. Signed-off-by: Peter Zijlstra (Intel) --- kernel/sched/core.c | 16 ++++++++-------- kernel/sched/stats.h | 2 ++ 2 files changed, 10 insertions(+), 8 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1630,16 +1630,16 @@ ttwu_stat(struct task_struct *p, int cpu #ifdef CONFIG_SMP if (cpu == rq->cpu) { - schedstat_inc(rq->ttwu_local); - schedstat_inc(p->se.statistics.nr_wakeups_local); + __schedstat_inc(rq->ttwu_local); + __schedstat_inc(p->se.statistics.nr_wakeups_local); } else { struct sched_domain *sd; - schedstat_inc(p->se.statistics.nr_wakeups_remote); + __schedstat_inc(p->se.statistics.nr_wakeups_remote); rcu_read_lock(); for_each_domain(rq->cpu, sd) { if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { - schedstat_inc(sd->ttwu_wake_remote); + __schedstat_inc(sd->ttwu_wake_remote); break; } } @@ -1647,14 +1647,14 @@ ttwu_stat(struct task_struct *p, int cpu } if (wake_flags & WF_MIGRATED) - schedstat_inc(p->se.statistics.nr_wakeups_migrate); + __schedstat_inc(p->se.statistics.nr_wakeups_migrate); #endif /* CONFIG_SMP */ - schedstat_inc(rq->ttwu_count); - schedstat_inc(p->se.statistics.nr_wakeups); + __schedstat_inc(rq->ttwu_count); + __schedstat_inc(p->se.statistics.nr_wakeups); if (wake_flags & WF_SYNC) - schedstat_inc(p->se.statistics.nr_wakeups_sync); + __schedstat_inc(p->se.statistics.nr_wakeups_sync); } static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -31,6 +31,7 @@ rq_sched_info_dequeued(struct rq *rq, un rq->rq_sched_info.run_delay += delta; } #define schedstat_enabled() static_branch_unlikely(&sched_schedstats) +#define __schedstat_inc(var) do { var++; } while (0) #define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0) #define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0) #define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0) @@ -48,6 +49,7 @@ static inline void rq_sched_info_depart(struct rq *rq, unsigned long long delta) {} #define schedstat_enabled() 0 +#define __schedstat_inc(var) do { } while (0) #define schedstat_inc(var) do { } while (0) #define schedstat_add(var, amt) do { } while (0) #define schedstat_set(var, val) do { } while (0)