Move the update of idle_stamp from idle_balance to the call site in pick_next_task_fair, to prepare for a future patch that adds work to pick_next_task_fair which must be included in the idle_stamp interval. No functional change.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com> --- kernel/sched/fair.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c623338..305edf8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3724,6 +3724,8 @@ static inline bool within_margin(int value, int margin) WRITE_ONCE(p->se.avg.util_est, ue); } +#define IF_SMP(statement) statement + static void overload_clear(struct rq *rq) { struct sparsemask *overload_cpus; @@ -3769,6 +3771,8 @@ static inline int idle_balance(struct rq *rq, struct rq_flags *rf) return 0; } +#define IF_SMP(statement) /* empty */ + static inline void overload_clear(struct rq *rq) {} static inline void overload_set(struct rq *rq) {} @@ -6740,8 +6744,17 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ return p; idle: + /* + * We must set idle_stamp _before_ calling idle_balance(), such that we + * measure the duration of idle_balance() as idle time. + */ + IF_SMP(rq->idle_stamp = rq_clock(rq);) + new_tasks = idle_balance(rq, rf); + if (new_tasks) + IF_SMP(rq->idle_stamp = 0;) + /* * Because idle_balance() releases (and re-acquires) rq->lock, it is * possible for any higher priority task to appear. In that case we @@ -9504,12 +9517,6 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) u64 curr_cost = 0; /* - * We must set idle_stamp _before_ calling idle_balance(), such that we - * measure the duration of idle_balance() as idle time. - */ - this_rq->idle_stamp = rq_clock(this_rq); - - /* * Do not pull tasks towards !active CPUs... */ if (!cpu_active(this_cpu)) @@ -9600,9 +9607,6 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) if (this_rq->nr_running != this_rq->cfs.h_nr_running) pulled_task = -1; - if (pulled_task) - this_rq->idle_stamp = 0; - rq_repin_lock(this_rq, rf); return pulled_task; -- 1.8.3.1