Re: [PATCH 6/6] sched: disabled rt-bandwidth by default

[Max Krasnyansky]

Andi Kleen wrote:
> On Thu, Aug 28, 2008 at 01:19:13PM +0200, Peter Zijlstra wrote:
> > On Thu, 2008-08-28 at 13:09 +0200, Andi Kleen wrote:
> > > > Even if the system has multiple CPUs, and even if just a single CPU is
> > > > fully utilized by an RT task, without the rt-limit the system will still
> > > > lock up in practice due to various other factors: workqueues and tasks
> > > > being 'stuck' on CPUs that host an RT hog.
> > > The load balancer will not notice that a particular CPU is busy
> > > with real time tasks?
> > Not currently, working on that though.
>
> I wonder if it would make sense to break affinities in extreme case?
> With that even the workqueues would work again.

Please lets not break affinity :).

I'm going to submit patches (soonish) that convert drivers/etc to use 
cancel_work_sync()/flush_work() instead of flush_scheduled_work().
That takes care of the
    "machine getting stuck because workqueue thread is starved"
case.

Max
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/