Since task utilization is accrued only on the root cfs_rq, there are a couple of places where the se has to be synced with the root cfs_rq:
(1) The root cfs_rq has to be updated in attach_entity_load_avg() for an se representing a task in a tg other than the root tg before the se utilization can be added to it. (2) The last_update_time value of the root cfs_rq can be higher than the one of the cfs_rq the se is enqueued in. Call __update_load_avg() on the se with the last_update_time value of the root cfs_rq before removing se's utilization from the root cfs_rq in [remove|detach]_entity_load_avg(). In case the difference between the last_update_time value of the cfs_rq and the root cfs_rq is smaller than 1024ns, the additional calls to __update_load_avg() will bail early. Signed-off-by: Dietmar Eggemann <dietmar.eggem...@arm.com> --- kernel/sched/fair.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 212becd3708f..3ae8e79fb687 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2970,6 +2970,8 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { + struct cfs_rq* root_cfs_rq; + if (!sched_feat(ATTACH_AGE_LOAD)) goto skip_aging; @@ -2995,8 +2997,16 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s if (!entity_is_task(se)) return; - rq_of(cfs_rq)->cfs.avg.util_avg += se->avg.util_avg; - rq_of(cfs_rq)->cfs.avg.util_sum += se->avg.util_sum; + root_cfs_rq = &rq_of(cfs_rq)->cfs; + + if (parent_entity(se)) + __update_load_avg(cfs_rq_clock_task(root_cfs_rq), + cpu_of(rq_of(root_cfs_rq)), &root_cfs_rq->avg, + scale_load_down(root_cfs_rq->load.weight), + upd_util_cfs_rq(root_cfs_rq), root_cfs_rq); + + root_cfs_rq->avg.util_avg += se->avg.util_avg; + root_cfs_rq->avg.util_sum += se->avg.util_sum; cfs_rq_util_change(cfs_rq); } @@ -3013,6 +3023,10 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s if (!entity_is_task(se)) return; + __update_load_avg(rq_of(cfs_rq)->cfs.avg.last_update_time, cpu_of(rq_of(cfs_rq)), + &se->avg, se->on_rq * scale_load_down(se->load.weight), + cfs_rq->curr == se, NULL); + rq_of(cfs_rq)->cfs.avg.util_avg = max_t(long, rq_of(cfs_rq)->cfs.avg.util_avg - se->avg.util_avg, 0); rq_of(cfs_rq)->cfs.avg.util_sum = @@ -3105,6 +3119,9 @@ void remove_entity_load_avg(struct sched_entity *se) if (!entity_is_task(se)) return; + last_update_time = cfs_rq_last_update_time(&rq_of(cfs_rq)->cfs); + + __update_load_avg(last_update_time, cpu_of(rq_of(cfs_rq)), &se->avg, 0, 0, NULL); atomic_long_add(se->avg.util_avg, &rq_of(cfs_rq)->cfs.removed_util_avg); } -- 1.9.1