Messages in this thread | | | Date | Thu, 16 Nov 2023 19:16:29 +0800 | Subject | Re: [PATCH 1/1] sched/fair: Update min_vruntime in more relaxed way | From | Abel Wu <> |
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On 11/16/23 6:54 PM, Yiwei Lin Wrote: > As EEVDF adopts lag-based solution which is irrespective of > min_vruntime like CFS before, min_vruntime is only used as > an offset to avoid overflow on evaluation of avg_vruntime now. > Rely on the fact we will always update_curr() before change > to cfs_rq, it seems to make sense if we just > update_min_vruntime() with update_curr() to reduce the cost. > > Signed-off-by: Yiwei Lin <s921975628@gmail.com> > --- > kernel/sched/fair.c | 20 +------------------- > 1 file changed, 1 insertion(+), 19 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 07f555857..5c40adfae 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3815,17 +3815,8 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, > enqueue_load_avg(cfs_rq, se); > if (se->on_rq) { > update_load_add(&cfs_rq->load, se->load.weight); > - if (!curr) { > - /* > - * The entity's vruntime has been adjusted, so let's check > - * whether the rq-wide min_vruntime needs updated too. Since > - * the calculations above require stable min_vruntime rather > - * than up-to-date one, we do the update at the end of the > - * reweight process. > - */ > + if (!curr) > __enqueue_entity(cfs_rq, se); > - update_min_vruntime(cfs_rq); > - } > } > } > > @@ -5347,15 +5338,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > > update_cfs_group(se); > > - /* > - * Now advance min_vruntime if @se was the entity holding it back, > - * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be > - * put back on, and if we advance min_vruntime, we'll be placed back > - * further than we started -- ie. we'll be penalized. > - */ > - if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) > - update_min_vruntime(cfs_rq); > - > if (cfs_rq->nr_running == 0) > update_idle_cfs_rq_clock_pelt(cfs_rq); > }
For now, core pick of core scheduling relies on min_vruntime to be fresh, so please just fix commit eab03c23c2a1 to preserve its original behavior by moving update_min_vruntime() to proper position. And behavior change can be posted separated.
BTW it seems unnecessary to include a cover-letter for a single patch.
Thanks, Abel
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