Re: [RFC PATCH v2] sched/deadline: support dl task migration during cpu hotplug

[Wanpeng Li <kernellwp@gmail.com>]

Hi Peter,
On 14/11/5 下午6:50, Peter Zijlstra wrote:
> On Wed, Nov 05, 2014 at 04:51:57PM +0800, Wanpeng Li wrote:
>> Note: dl task can be migrated successfully if rq is offline currently, however,
>> I'm still not sure why task_rq(task)->rd->span just include the cpu which the dl
>> task previous running on, so cpu_active_mask is used in the patch.
>>
>> Peterz, Juri?
> So the root domain span is for exclusive cpusets
> (Documentation/cgroups/cpusets.txt) where we fully separate sets of CPUs
> and have no load-balancing between the sets.
>
> For 'normal' setups the rd->span is the entire machine, but using
> cpusets you can create more (smaller) domains.

I don't setup any cpusets related stuff, however, 
task_rq(task)->rd->span just include the cpu which the dl task previous 
running on instead of the entire machine in find_later_rq().

Regards,
Wanpeng Li

>
> Is this what you were asking?
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