Messages in this thread | | | Date | Thu, 11 Feb 2016 12:27:54 +0000 | From | Juri Lelli <> | Subject | Re: [PATCH 1/2] sched/deadline: add per rq tracking of admitted bandwidth |
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On 11/02/16 13:22, Luca Abeni wrote: > Hi Juri, > > On Thu, 11 Feb 2016 12:12:57 +0000 > Juri Lelli <juri.lelli@arm.com> wrote: > [...] > > 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. > In my patch I took care of the first case (modifying > select_task_rq_dl() to move the utilization from the "old rq" to the > "new rq"), but I never managed to trigger select_fallback_rq() in my > tests, so I overlooked that case. >
Right, I was thinking to do the same. And you did that after grabbing both locks, right?
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