Messages in this thread | | | Date | Mon, 20 Jun 2016 16:27:34 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 4/4] sched,fair: Fix PELT integrity for new tasks |
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On Mon, Jun 20, 2016 at 12:35:59PM +0100, Dietmar Eggemann wrote: > > > On 17/06/16 17:18, Peter Zijlstra wrote: > > On Fri, Jun 17, 2016 at 06:02:39PM +0200, Peter Zijlstra wrote: > >> So yes, ho-humm, how to go about doing that bestest. Lemme have a play. > > > > This is what I came up with, not entirely pretty, but I suppose it'll > > have to do. > > > > --- > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -724,6 +724,7 @@ void post_init_entity_util_avg(struct sc > > struct cfs_rq *cfs_rq = cfs_rq_of(se); > > struct sched_avg *sa = &se->avg; > > long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2; > > + u64 now = cfs_rq_clock_task(cfs_rq); > > > > if (cap > 0) { > > if (cfs_rq->avg.util_avg != 0) { > > @@ -738,7 +739,20 @@ void post_init_entity_util_avg(struct sc > > sa->util_sum = sa->util_avg * LOAD_AVG_MAX; > > } > > > > - update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, false); > > + if (entity_is_task(se)) { > > + struct task_struct *p = task_of(se); > > + if (p->sched_class != &fair_sched_class) { > > + /* > > + * For !fair tasks do attach_entity_load_avg() > > + * followed by detach_entity_load_avg() as per > > + * switched_from_fair(). > > + */ > > + se->avg.last_update_time = now; > > + return; > > + } > > + } > > + > > + update_cfs_rq_load_avg(now, cfs_rq, false); > > attach_entity_load_avg(cfs_rq, se); > > } > > > > > > Doesn't a sleeping !fair_sched_class task which switches to fair uses > try_to_wake_up() rather than wake_up_new_task() so it won't go through > post_init_entity_util_avg()?
Its switched_to_fair() that'll fix that up.
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