Re: [PATCH v3] sched/deadline: do not try to push tasks if pinned task switches to dl

From: Peter Zijlstra
Date: Wed Mar 30 2016 - 02:45:08 EST


On Tue, Mar 29, 2016 at 06:47:22PM -0400, Steven Rostedt wrote:
> I'm looking at some old changes for sched-deadline, and I stumbled
> across this. As I'm working on sched deadline tests, I've discovered
> that they can't have cpu affinity. They are limited to their sched
> domains. That is, sched deadline tasks have whatever affinity that the
> domain they happen to be in has.
>
> Is there a condition where rq != task_rq(p) and p->nr_cpus_allowed > 1
> isn't true?

When holding rq->lock, no. I suppose the patch was just to mirror rt and
someone 'forgot' about the extra constraints on dl tasks.