On Tue, Nov 27 2001, Andrew Morton wrote:
> Jens Axboe wrote:
> >
> > I agree that the current i/o scheduler has really bad interactive
> > performance -- at first sight your changes looks mostly like add-on
> > hacks though.
>
> Good hacks, or bad ones?
>
> It keeps things localised. It works. It's tunable. It's the best
> IO scheduler presently available.
Hacks look ok on cursory glances :-)
> > Arjan's priority based scheme is more promising.
>
> If the IO priority becomes an attribute of the calling process
> then an approach like that has value. For writes, the priority
> should be driven by VM pressure and it's probably simpler just
> to stick the priority into struct buffer_head -> struct request.
> For reads, the priority could just be scooped out of *current.
>
> If we're not going to push the IO priority all the way down from
> userspace then you may as well keep the logic inside the elevator
> and just say reads-go-here and writes-go-there.
Priority will be passed down for reads as you suggest, at least that is
the intention I had as well. I've only worked on 2.5 with this, but I
guess we can find some space in the buffer_head to squeeze in some
priority bits.
> But this has potential to turn into a great designfest. Are
Oh yeah
> we going to leave 2.4 as-is? Please say no.
I'd be happy to review anything you come up with -- or in other works,
feel free to knock yourself out, I'm busy with other stuff currently :)
-- Jens Axboe- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Nov 30 2001 - 21:00:26 EST