Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 10 Nov 2003 15:44:12 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH] cfq-prio #2 |
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On Tue, Nov 11 2003, Nick Piggin wrote: > > > Jens Axboe wrote: > > >On Tue, Nov 11 2003, Nick Piggin wrote: > > > >> > >>You acked the change actually :P > >>I guess it was done in mainline when AS was merged. > >> > > > >Probably missed the semantic change of may_queue. > > > > Anyway I won't bother digging up the email, its been done now.
Yeah too late to change now...
> >>>>Maybe my version should be called elv_force_queue? > >>>> > >>>> > >>>I just hate to see more of these, really. The original idea for > >>>may_queue was just that, may this process queue io or not. We can make > >>>it return something else, though, to indicate whether the process must > >>>be able to queue. Is it really needed? > >>> > >>> > >>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.
-- Jens Axboe
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