Re: [patch 2.6.25-rc5 1/2] gpiolib: dynamic gpio number allocation

[Anton Vorontsov <cbouatmailru@gmail.com>]

On Thu, Mar 13, 2008 at 04:28:03PM -0700, Andrew Morton wrote:
> On Thu, 13 Mar 2008 15:18:58 -0800
> David Brownell <david-b@pacbell.net> wrote:
> 
> > On Thursday 13 March 2008, Andrew Morton wrote:
> > 
> > > hm.  I suppose that if someone want a huge number of GPIOs then we can
> > > convert this to a bitmap or an IDR tree easily enough.
> > 
> > Actually, I tried IDRs for a while and they broke platforms
> > which needed to initialize and use GPIOs early: before kmalloc
> > would work.  A real PITA that was -- and slow too.
> 
> If IDRs were slow, that linear search will be glacial.

Heh.. FWIW, I didn't notice any slowness of that linear search.

I didn't bother to try anything more complicated than linear search
for mere 256 GPIOs. I doubt that IDRs will pour out into any
measurable win even for something like 1024 GPIOs.

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2