RE: [Xen-devel] unfair servicing of DomU vbd requests

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

> > > It appears that Dom0 is not servicing vbd requests from DomU's fairly so
> > > one or two end up getting stalled while the others are mostly okay. How
> > > are vbd requests supposed to be serviced? Is there potential for one to
> > > be overlooked for a long period of time? Is there some settings that
> > > could be changed to avoid this happening?
> >
> > Dom0 does round-robin scanning of pending event channels these days, which
> > helps fairness a fair bit.
> 
> I have a feeling this isn't true of pvops kernels...
> 
> looks like we need to pull 324:7fe1c6d02a2b (and subsequent fixes) out
> of 2.6.18-xen.hg into the pvops world.
> 

I hope that's true and easy to fix. It would certainly explain why one DomU can 
starve enough to the point where it's IO doesn't get serviced for >70 seconds.

Thanks for looking at this.

James

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