From 840c5abca499a858619954dbcffc82110bb6e076 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 6 May 2017 16:11:34 +0200 Subject: sched/fair: More accurate reweight_entity() When a (group) entity changes it's weight we should instantly change its load_avg and propagate that change into the sums it is part of. Because we use these values to predict future behaviour and are not interested in its historical value. Without this change, the change in load would need to propagate through the average, by which time it could again have changed etc.. always chasing itself. With this change, the cfs_rq load_avg sum will more accurately reflect the current runnable and expected return of blocked load. Reported-by: Paul Turner [josef: compile fix !SMP || !FAIR_GROUP] Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel/sched') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 654d8e3d6047..750ae4dbf812 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2886,12 +2886,22 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, if (cfs_rq->curr == se) update_curr(cfs_rq); account_entity_dequeue(cfs_rq, se); + dequeue_runnable_load_avg(cfs_rq, se); } + dequeue_load_avg(cfs_rq, se); update_load_set(&se->load, weight); - if (se->on_rq) +#ifdef CONFIG_SMP + se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, + LOAD_AVG_MAX - 1024 + se->avg.period_contrib); +#endif + + enqueue_load_avg(cfs_rq, se); + if (se->on_rq) { account_entity_enqueue(cfs_rq, se); + enqueue_runnable_load_avg(cfs_rq, se); + } } static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); -- cgit