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Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted bandwidth

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On 10/02/16 16:27, Juri Lelli wrote:
> On 10/02/16 09:37, Steven Rostedt wrote:
> > On Wed, 10 Feb 2016 11:32:58 +0000
> > Juri Lelli <juri.lelli@arm.com> wrote:
> > 

[...]

> > 
> > I applied this patch and patch 2 and hit this:
> > 

[...]

> > 
> > It's the warning you added in __dl_sub_ac().
> > 
> 
> OK. There are still holes where we fail to properly update per-rq bw. It
> seems (by running you test) that we fail to move the per-rq bw when we
> move the root_domain bw due css_set_move_task(). So, the final
> task_dead_dl() tries to remove bw from where there isn't.
> 
> I'm trying to see how we can close this hole.
> 

So, just to give an update from yesterday (kind of tricky this one :/).

I think we still have (at least) two problems:

 - select_task_rq_dl, if we select a different target
 - select_task_rq might make use of select_fallback_rq, if cpus_allowed
   changed after the task went to sleep

Second case is what creates the problem here, as we don't update
task_rq(p) and fallback_cpu ac_bw. I was thinking we might do so, maybe
adding fallback_cpu in task_struct, from migrate_task_rq_dl() (it has to
be added yes), but I fear that we should hold both rq locks :/.

Luca, did you already face this problem (if I got it right) and thought
of a way to fix it? I'll go back and stare a bit more at those paths.

Best,

- Juri

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Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-10 12:40 +0100
  Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-10 12:50 +0100
    Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-10 13:00 +0100
      Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-19 14:50 +0100
        Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Steven Rostedt <rostedt@goodmis.org> - 2016-02-19 15:30 +0100
          Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Steven Rostedt <rostedt@goodmis.org> - 2016-02-19 16:00 +0100
          Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-19 16:00 +0100
            Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-22 12:10 +0100
      [PATCH 0/3] cleanup per rq tracking of admitted bandwidth  Luca Abeni <luca.abeni@unitn.it> - 2016-02-22 12:00 +0100
        [PATCH 2/4] Move the remaining __dl_{sub,add}_ac() calls from core.c to deadline.c Luca Abeni <luca.abeni@unitn.it> - 2016-02-22 12:00 +0100
        [PATCH 1/4] Move some calls to __dl_{sub,add}_ac() from core.c to deadline.c Luca Abeni <luca.abeni@unitn.it> - 2016-02-22 12:00 +0100
        [PATCH 3/4] Remove dl_new Luca Abeni <luca.abeni@unitn.it> - 2016-02-22 12:00 +0100
  Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-10 13:50 +0100
    Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-10 14:50 +0100
  Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Steven Rostedt <rostedt@goodmis.org> - 2016-02-10 15:40 +0100
    Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-10 17:30 +0100
      Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-11 13:20 +0100
        Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-11 13:30 +0100
          Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-11 13:30 +0100
            Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-11 13:50 +0100
              Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-11 14:10 +0100
                Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Steven Rostedt <rostedt@goodmis.org> - 2016-02-11 15:30 +0100
                Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-11 18:10 +0100
                Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Peter Zijlstra <peterz@infradead.org> - 2016-02-12 18:10 +0100
                Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Juri Lelli <juri.lelli@arm.com> - 2016-02-12 18:20 +0100
                Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth Luca Abeni <luca.abeni@unitn.it> - 2016-02-11 22:50 +0100
            Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted  bandwidth luca abeni <luca.abeni@unitn.it> - 2016-02-11 13:50 +0100

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