Bug#631945: HFSC warning issue

[François Delawarde <fdelawarde@wirelessmundi.com>]

On Wed, 2011-07-13 at 01:28 +0200, Michal Soltys wrote: 
> That warning that gets triggered when next_time == 0 in
> hfsc_schedule_watchdog() implies, that hfsc_dequeue() tried to dequeue a
> packet, but no leaf had anything eligible for scheduling (realtime
> criterion) and linksharing was upperlimited.
> 
> Now if there IS something to dequeue, then I don't see how next_time
> could possibly be zero - that would mean there's no packet to schedule
> at all. But if that happened, then hfsc_dequeue() would simply exit at
> the very beginning due to: if (sch->q.qlen == 0) .
> 
> So it does look weird (like if something external messed with hfsc's
> qlen) ...

Could it be related with setting a custom device qlen with iproute (wild
guess)? 

> Also note - the changes to sch_hfsc.c were pretty minimal since the last
> kernel that worked for you. You might be searching for something else ...

Any idea where we could start searching?

Is there any configuration we could try (with upperlimits maybe?) that
could help identify or workaround this problem?

Thanks,
François.