Rounding in PELT calculation happening when entities are attached/detached of a cfs_rq can result into situations where util/runnable_avg is not null but util/runnable_sum is. This is normally not possible so we need to ensure that util/runnable_sum stays synced with util/runnable_avg. detach_entity_load_avg() is the last place where we don't sync util/runnable_sum with util/runnbale_avg when moving some sched_entities
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| @@ -3765,11 +3765,17 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s · 3764 unmodified lines | ||
| 3765 | 3765 | */ |
| 3766 | 3766 | static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) |
| 3767 | 3767 | { |
| 3768 | + /* | |
| 3769 | + * cfs_rq->avg.period_contrib can be used for both cfs_rq and se. | |
| 3770 | + * See ___update_load_avg() for details. | |
| 3771 | + */ | |
| 3772 | + u32 divider = get_pelt_divider(&cfs_rq->avg); | |
| 3773 | + | |
| 3768 | 3774 | dequeue_load_avg(cfs_rq, se); |
| 3769 | 3775 | sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg); |
| 3770 | − sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum); | |
| 3776 | + cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * divider; | |
| 3771 | 3777 | sub_positive(&cfs_rq->avg.runnable_avg, se->avg.runnable_avg); |
| 3772 | − sub_positive(&cfs_rq->avg.runnable_sum, se->avg.runnable_sum); | |
| 3778 | + cfs_rq->avg.runnable_sum = cfs_rq->avg.runnable_avg * divider; | |
| 3773 | 3779 | |
| 3774 | 3780 | add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum); |
| 3775 | 3781 | |