Re: [RFC PATCH v2 7/7] sched/fair: alternative way of accounting throttle time

Florian Bezdeka
2025-04-23T12:16:03Z

On Wed, 2025-04-23 at 19:26 +0800, Aaron Lu wrote:
> On Tue, Apr 22, 2025 at 05:03:19PM +0200, Florian Bezdeka wrote:
> ... ...
>
> > Right, I should have mentioned that crucial detail. Sorry.
> >
> > I ported your series to 6.14.2 because we did/do not trust anything
> > newer yet for testing. The problematic workload was not available in
> > our lab at that time, so we had to be very carefully about deployed
> > kernel versions.
> >
> > I'm attaching the backported patches now, so you can compare / review
> > if you like. Spoiler: The only differences are line numbers ;-)
>
> I didn't notice any problem regarding backport after a quick look.
>
> May I know what kind of workload triggered this warning? I haven't been
> able to trigger it, I'll have to stare harder at the code.

There are a couple of containers running. Nothing special as far as I
can tell. Network, IO, at least one container heavily using the epoll
interface.

The system is still operating fine though...

Once again: PREEMPT_RT enabled, so maybe handling an IRQ over the
accounting code could happen? Looking at the warning again it looks
like unthrottle_cfs_rq() is called from IRQ context. Is that expected?

Best regards,
Florian