The following patches properly intergrate sched domains and cpu hotplug (using
Nathan's code), by having sched-domains *always* only represent online CPUs,
and having hotplug notifier to keep them up to date.

Then tackle Jesse's domain setup problem: the disjoint top-level domains were
completely broken.  The group-list builder thingy simply can't handle distinct
sets of groups containing the same CPUs.  The code is ugly and specific enough
that I'm re-introducing the arch overridable domains.

I doubt we'll get a proliferation of implementations, because the current
generic code can do the job for everyone but SGI.  I'd rather take a look at
it again down the track if we need to rather than try to shoehorn this into
the generic code.

Nathan and I have tested the hotplug work. He's happy with it.

I've tested the disjoint domain stuff (copied it to i386 for the test), and it
does the right thing on the NUMAQ.  I've asked Jesse to test it as well, but
it should be fine - maybe just help me out and run a test compile on ia64 ;)

This really gets sched domains into much better shape.  Without further ado,
the patches.



This patch:

Make a definition static and slightly sanitize ifdefs.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>