Re: [PATCH] cfq-prio #2

[Nick Piggin]

Jens Axboe wrote:

> On Tue, Nov 11 2003, Nick Piggin wrote:
>
> > Jens Axboe wrote:
> >
> >
> > > On Tue, Nov 11 2003, Nick Piggin wrote:
> > >
> > >
> > > > >
> > > > Its quite important. If the queue is full, and AS is waiting for a process
> > > > to submit a request, its got a long wait.
> > > >
> > > > Maybe a lower limit for per process nr_requests. Ie. you may queue if this
> > > > queue has less than 128 requests _or_ you have less than 8 requests
> > > > outstanding. This would solve my problem. It would also give you a much 
> > > > more
> > > > appropriate scaling for server workloads, I think. Still, thats quite a
> > > > change in behaviour (simple to code though).
> > > That basically belongs inside your may_queue for the io scheduler, imo.
> > You can force it to disallow the request, but you can't force it to allow
> > one (depending on a successful memory allocation, of course).
>
> Well that's back two mails then, make may_queue return whether you must
> queue, may queue, or can't queue.

Yep, sounds good. I'll make a patch for it for 2.6.x > 0 sometime unless
you beat me to it.


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