[dm-devel] Re: IO scheduler based IO controller V10

[Mike Galbraith <efault gmx de>]

On Fri, 2009-10-02 at 20:08 +0200, Jens Axboe wrote:
> On Thu, Oct 01 2009, Mike Galbraith wrote:
> >  	max_dispatch = cfqd->cfq_quantum;
> >  	if (cfq_class_idle(cfqq))
> >  		max_dispatch = 1;
> >  
> > +	if (cfqd->busy_queues > 1)
> > +		cfqd->od_stamp = jiffies;
> > +
> 
> ->busy_queues > 1 just means that they have requests ready for dispatch,
> not that they are dispatched.

But we're not alone, somebody else is using disk.  I'm trying to make
sure we don't have someone _about_ to come back.. like a reader, so when
there's another player, stamp to give him some time to wake up/submit
before putting the pedal to the metal.

	-Mike