Messages in this thread Patch in this message | | | From | Kirill Tkhai <> | Subject | Re: [RFC] sched/deadline: Prevent rt_time growth to infinity | Date | Fri, 21 Feb 2014 15:33:38 +0400 |
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21.02.2014, 14:37, "Peter Zijlstra" <peterz@infradead.org>: > On Thu, Feb 20, 2014 at 02:16:00AM +0400, Kirill Tkhai wrote: > >> Since deadline tasks share rt bandwidth, we must care about >> bandwidth timer set. Otherwise rt_time may grow up to infinity >> in update_curr_dl(), if there are no other available RT tasks >> on top level bandwidth. >> >> I'm going to decide the problem the way below. Almost untested >> because of I skipped almost all of recent patches which haveto be applied from lkml. >> >> Please say, if I skipped anything in idea. Maybe better put >> start_top_rt_bandwidth() into set_curr_task_dl()? > > How about we only increment rt_time when there's an RT bandwidth timer > active?
This case RT and DL may eat all the time:
-------------- time ------------------> |RT's working |DL's working| ---------------------------- |rt_runtime | | ---------------------------- | rt_period |
Or at least more, than it's allowed.
It looks like, if we want to limit time of high priority classes execution, we have to set the timer anyway.
> --- > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -568,6 +568,12 @@ static inline struct rt_bandwidth *sched
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