Messages in this thread | | | Date | Wed, 1 Jun 2016 02:37:49 +0800 | From | Yuyang Du <> | Subject | Re: [PATCH v2 1/3] sched/fair: Clean up attach_entity_load_avg() |
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On Tue, May 31, 2016 at 10:34:02AM +0200, Peter Zijlstra wrote: > On Tue, May 31, 2016 at 06:32:54AM +0800, Yuyang Du wrote: > > +++ b/kernel/sched/fair.c > > @@ -2961,24 +2961,6 @@ 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) > > { > > - if (!sched_feat(ATTACH_AGE_LOAD)) > > - goto skip_aging; > > - > > - /* > > - * If we got migrated (either between CPUs or between cgroups) we'll > > - * have aged the average right before clearing @last_update_time. > > - */ > > - if (se->avg.last_update_time) { > > - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), > > - &se->avg, 0, 0, NULL); > > - > > - /* > > - * XXX: we could have just aged the entire load away if we've been > > - * absent from the fair class for too long. > > - */ > > - } > > - > > -skip_aging: > > se->avg.last_update_time = cfs_rq->avg.last_update_time; > > cfs_rq->avg.load_avg += se->avg.load_avg; > > cfs_rq->avg.load_sum += se->avg.load_sum; > > So I'm not a big fan of this patch; the aging is a conceptual part of > attaching the load, the fact that it only happens in one callsite is a > mere 'accident'.
Yes, and we have to put the following to make it an "accident".
static void task_move_group_fair(struct task_struct *p) { detach_task_cfs_rq(p); set_task_rq(p, task_cpu(p));
#ifdef CONFIG_SMP /* Tell se's cfs_rq has been changed -- migrated */ p->se.avg.last_update_time = 0; ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #endif attach_task_cfs_rq(p); }
So let me give it another try to keep this cleanup. Will send another version.
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