Re: [PATCH] sched/rt: Rework for_each_process_thread() iterations in tg_has_rt_tasks()

From: Juri Lelli
Date: Fri Apr 20 2018 - 06:59:02 EST


On 20/04/18 12:43, Kirill Tkhai wrote:
> On 20.04.2018 12:25, Juri Lelli wrote:

[...]

> > Isn't this however checking against the current (dynamic) number of
> > runnable tasks/groups instead of the "static" group membership (which
> > shouldn't be affected by a task running state)?
>
> Ah, you are sure. I forgot that rt_nr_running does not contain sleeping tasks.
> We need to check something else here. I'll try to find another way.

n/p. Maybe a per rt_rq flag linked to "static" membership (I didn't
really thought this through though :).

BTW, since you faced this problem, I guess this is on RT_GROUP_SCHED
enabled boxes, so I'd have a couple of questions (not strictly related
to the problem at hand):

- do such boxes rely on RT throttling being performed at root level?
- is RT_RUNTIME_SHARE enabled?

Thanks,

- Juri