Re: [Xen-devel] BUG: sched=credit2 crashes system when using cpupools

[Steven Haigh <netwiz@xxxxxxxxx>]

On 2018-08-30 18:33, Jan Beulich wrote:
> > > > On 30.08.18 at 06:01, <netwiz@xxxxxxxxx> wrote:
> > Managed to get the same crash log when adding CPUs to Pool-1 as 
> > follows:
> > Create the pool:
> > (XEN) Initializing Credit2 scheduler
> > (XEN)  load_precision_shift: 18
> > (XEN)  load_window_shift: 30
> > (XEN)  underload_balance_tolerance: 0
> > (XEN)  overload_balance_tolerance: -3
> > (XEN)  runqueues arrangement: socket
> > (XEN)  cap enforcement granularity: 10ms
> > (XEN) load tracking window length 1073741824 ns
> >
> > Add the CPUs:
> > (XEN) Adding cpu 12 to runqueue 0
> > (XEN)  First cpu on runqueue, activating
> > (XEN) Removing cpu 12 from runqueue 0
> > (XEN) Adding cpu 13 to runqueue 0
> > (XEN) Removing cpu 13 from runqueue 0
> > (XEN) Adding cpu 14 to runqueue 0
> > (XEN) Removing cpu 14 from runqueue 0
> > (XEN) Xen BUG at sched_credit2.c:3452
> credit2 still not being the default - do things work if you don't 
> override
> the default (of using credit1)? I guess the problem is connected to the
> "Removing cpu <N> from runqueue 0", considering this
>
>     BUG_ON(!cpumask_test_cpu(cpu, &rqd->active));
>
> is what triggers. Anyway - as Jürgen says, something for the scheduler
> maintainers to look into.
Yep - I just want to confirm that we tested this in BOTH NUMA 
configurations - and credit2 crashed on both.
I switched back to sched=credit, and it seems to work as expected:
# xl cpupool-list
Name               CPUs   Sched     Active   Domain count
Pool-node0          12    credit       y          3
Pool-node1          12    credit       y          0

I've updated the subject - as this isn't a NUMA issue at all.

--
Steven Haigh

? netwiz@xxxxxxxxx     ? http://www.crc.id.au
? +61 (3) 9001 6090    ? 0412 935 897

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel