Messages in this thread | | | Date | Mon, 22 Jul 2019 14:28:28 +0200 | From | Juri Lelli <> | Subject | Re: [PATCH v9 4/8] sched/deadline: Fix bandwidth accounting at all levels after offline migration |
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On 22/07/19 13:07, Dietmar Eggemann wrote: > On 7/19/19 3:59 PM, Juri Lelli wrote: > > [...] > > > @@ -557,6 +558,38 @@ static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p > > double_lock_balance(rq, later_rq); > > } > > > > + if (p->dl.dl_non_contending || p->dl.dl_throttled) { > > + /* > > + * Inactive timer is armed (or callback is running, but > > + * waiting for us to release rq locks). In any case, when it > > + * will file (or continue), it will see running_bw of this > > s/file/fire ?
Yep.
> > + * task migrated to later_rq (and correctly handle it). > > Is this because of dl_task_timer()->enqueue_task_dl()->task_contending() > setting dl_se->dl_non_contending = 0 ?
No, this is related to inactive_task_timer() callback. Since the task is migrated (by this function calling set_task_cpu()) because a CPU hotplug operation happened, we need to reflect this w.r.t. running_bw, or inactive_task_timer() might sub from the new CPU and cause running_bw to underflow.
Thanks,
Juri
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