On Wed, Jan 17, 2018 at 10:32:12AM +0100, Thomas Gleixner wrote:
> On Wed, 17 Jan 2018, Thomas Gleixner wrote:
> > That doesn't sound right. The vectors should be spread evenly accross the
> > CPUs. So ENOSPC should never happen.
> > 
> > Can you please take snapshots of /sys/kernel/debug/irq/ between the
> > modprobe and modprobe -r steps?
> 
> The allocation fails because CPU1 has exhausted it's vector space here:
> 
> [002] d...   333.028216: irq_matrix_alloc_managed: bit=34 cpu=1 online=1 avl=0 alloc=202 managed=2 online_maps=112 global_avl=22085, global_rsvd=158, total_alloc=460
> 
> Now the interesting question is how that happens.

The trace with "trace_events=irq_matrix" kernel parameter is attached,
ended shortly after an allocation failure.

I'll have to get back to you on the debug/irq snapshots.