Messages in this thread | | | Date | Tue, 11 Nov 2014 19:55:19 +0800 | From | Wanpeng Li <> | Subject | Re: [RFC PATCH v3] sched/deadline: support dl task migration during cpu hotplug |
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Hi Peter, On 14/11/11 下午7:33, Peter Zijlstra wrote: > On Thu, Nov 06, 2014 at 10:40:49AM +0800, Wanpeng Li wrote: >> @@ -538,6 +539,46 @@ again: >> update_rq_clock(rq); >> dl_se->dl_throttled = 0; >> dl_se->dl_yielded = 0; >> + >> + /* >> + * So if we find that the rq the task was on is no longer >> + * available, we need to select a new rq. >> + */ >> + if (!rq->online) { >> + struct rq *later_rq = NULL; >> + >> + raw_spin_unlock(&rq->lock); >> + >> + later_rq = find_lock_later_rq(p, rq); >> + >> + if (!later_rq) { >> + int cpu; >> + >> + /* >> + * If cannot preempt any rq, fallback to pick any >> + * online cpu. >> + */ >> + for_each_cpu(cpu, &p->cpus_allowed) >> + if (cpu_online(cpu)) >> + later_rq = cpu_rq(cpu); > cpu = cpumask_any_and(cpu_active_mask, tsk_cpus_allowed(p)); > if (cpu >= nr_cpu_ids) > /* fail */ > > later_rq = cpu_rq(cpu);
Ok.
>> + if (!later_rq) { >> + pr_warn("fail to find any online and task >> + will never come back to us\n"); >> + goto out; >> + } >> + } >> + >> + deactivate_task(rq, p, 0); >> + set_task_cpu(p, later_rq->cpu); >> + activate_task(later_rq, p, 0); >> + >> + resched_curr(later_rq); >> + >> + double_unlock_balance(rq, later_rq); >> + >> + goto out; >> + } >> + >> if (task_on_rq_queued(p)) { >> enqueue_task_dl(rq, p, ENQUEUE_REPLENISH); >> if (dl_task(rq->curr)) >> @@ -555,7 +596,7 @@ again: >> } >> unlock: >> raw_spin_unlock(&rq->lock); >> - >> +out: >> return HRTIMER_NORESTART; >> } >> >> @@ -1185,8 +1226,12 @@ static int find_later_rq(struct task_struct *task) >> * We have to consider system topology and task affinity >> * first, then we can look for a suitable cpu. >> */ >> - cpumask_copy(later_mask, task_rq(task)->rd->span); >> - cpumask_and(later_mask, later_mask, cpu_active_mask); >> + if (likely(task_rq(task)->online)) { >> + cpumask_copy(later_mask, task_rq(task)->rd->span); >> + cpumask_and(later_mask, later_mask, cpu_active_mask); >> + } else >> + /* for offline cpus we have a singleton rd */ >> + cpumask_copy(later_mask, cpu_active_mask); >> cpumask_and(later_mask, later_mask, &task->cpus_allowed); >> best_cpu = cpudl_find(&task_rq(task)->rd->cpudl, >> task, later_mask); > cpumask_copy(later_mask, cpu_active_mask); > if (likely(task_rq(task)->online)) > cpumask_and(later_mask, later_mask, task_rq(task)->rd->span); > > Is the same, right and less lines.
Thanks for your great help! I will fold these to my patch and send out a newer version tomorrow. ;-)
Regards, Wanpeng Li
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