Messages in this thread | | | Date | Fri, 19 Oct 2018 22:50:05 +0200 | From | luca abeni <> | Subject | Re: INFO: rcu detected stall in do_idle |
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On Fri, 19 Oct 2018 13:39:42 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Oct 18, 2018 at 01:08:11PM +0200, luca abeni wrote: > > Ok, I see the issue now: the problem is that the "while > > (dl_se->runtime <= 0)" loop is executed at replenishment time, but > > the deadline should be postponed at enforcement time. > > > > I mean: in update_curr_dl() we do: > > dl_se->runtime -= scaled_delta_exec; > > if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) { > > ... > > enqueue replenishment timer at dl_next_period(dl_se) > > But dl_next_period() is based on a "wrong" deadline! > > > > > > I think that inserting a > > while (dl_se->runtime <= -pi_se->dl_runtime) { > > dl_se->deadline += pi_se->dl_period; > > dl_se->runtime += pi_se->dl_runtime; > > } > > immediately after "dl_se->runtime -= scaled_delta_exec;" would fix > > the problem, no? > > That certainly makes sense to me.
Good; I'll try to work on this idea in the weekend.
Thanks, Luca
> The only remaining issue would then > be placing a limit on the amount of times we can take that loop; > which, as you propose in a later email; can be done separately as a > limit on runtime.
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