Re: [PATCH RFC] sched/deadline: support dl task migrate during cpu hotplug

[Wanpeng Li <kernellwp@gmail.com>]

Hi Juri,
On 14/11/4 下午11:50, Juri Lelli wrote:
> Hi,
>
> On 04/11/14 15:46, Peter Zijlstra wrote:
>> On Tue, Nov 04, 2014 at 09:30:46PM +0800, Wanpeng Li wrote:
>>
>>
>>> + if (!rq->online) {
>>> + struct rq *latest_rq = NULL;
>>> + int cpu;
>>> + u64 dmin = LONG_MAX;
>>> +
>>> + for_each_cpu(cpu, &p->cpus_allowed)
>>> + if (cpu_online(cpu) &&
>>> + cpu_rq(cpu)->dl.earliest_dl.curr < dmin) {
>>> + latest_rq = cpu_rq(cpu);
>>> + dmin = latest_rq->dl.earliest_dl.curr;
>>> + }
>> I would have expected something using find_later_rq(), but I might be
>> mistaken, I'll let Juri suggest something.
>>
> Yeah, we should be able to reuse something that we already have. I'm
> actually sorry that I'm not responsive on this, but I'm really busy on
> other things this week. I hope to be able to find some time soon to test
> this all.

I have time to do it, your proposal is a great welcome. ;-)

Regards,
Wanpeng Li

>
> Thanks,
>
> - Juri
>
>>> +
>>> + if (!latest_rq)
>>> + goto unlock;
>>> +
>>> + raw_spin_lock(&latest_rq->lock);
>>> +
>>> + deactivate_task(rq, p, 0);
>>> + set_task_cpu(p, latest_rq->cpu);
>>> + activate_task(latest_rq, p, 0);
>>> +
>>> + raw_spin_unlock(&latest_rq->lock);
>>> + }
>>> +
>>> unlock:
>>> raw_spin_unlock(&rq->lock);