Re: elevator algorithm bug in ll_rw_blk.c
kwrohrer@ce.mediaone.net
Sun, 15 Nov 1998 11:17:19 -0600 (EST)
And lo, Chip Salzenberg saith unto me:
>
> But that's a *one-way* elevator. Ideal elevators are two-way, aren't they?
Depends on what you call "ideal". Bottom-up elevators are fairer to the
first and last parts of the disk than back-and-forth elevators are. But I
haven't seen any papers on how fair is "fair enough" in the general case.
I'd think not allowing processes to add more requests to the current pass
would be more important, and more likely necessary, than choosing one-way
over back-and-forth, for "typical" tasks. But I freely admit that my sense
of "typical" is intuitive, not concrete or even anecdotal...
Keith
--
"The avalanche has already started; |Linux: http://www.linuxhq.com |"Zooty,
it is too late for the pebbles to |KDE: http://www.kde.org | zoot
vote." Kosh, "Believers", Babylon 5 |Keith: kwrohrer@enteract.com | zoot!"
www.midwinter.com/lurk/lurker.html |http://www.enteract.com/~kwrohrer | --Rebo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/