Re: [patch] dynamic char and block devices
Martin Dalecki (dalecki@cs.net.pl)
Wed, 13 Oct 1999 20:08:39 +0200
Richard Gooch wrote:
>
> Jeff Garzik writes:
> > The attached patch against 2.3.21 updates fs/devices.c to be dynamic,
> > instead of using two static arrays indexed by major number.
>
> Oh, my! So now we have a list search on every device open. This is
> *exactly* one of the things I predicted 2 years ago in the devfs FAQ,
> once people started to fix the 16bit device size limitation.
>
> This just highlights one of my points that device numbers are
> fundamentally unscalable. With devfs you avoid this major index/list
> search/hash lookup entirely.
>
> Well, fine, if that's how you want to run your system. But at least
> let those of us who want to avoid this extra cost have the option.
>
> Regards,
>
> Richard....
What's yours problem anyway????????????
Or are you just always doing
for (i = 0; i < 10000000; ++i) {
open()
read()
close()
}
The lookup is neccesary only *ONCE*. The list order can be made
adaptable.
And the speed penalty should be lost in the noise of all the other
operations anyway.
--Marcin
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