General scheduling domains take 2

[Nick Piggin <piggin@cyberone.com.au>]

Hi,

http://www.kerneltrap.org/~npiggin/w24/

I have progressed a bit further, and the data structure is slightly
changed.

I have done code to build the scheduling description for SMT P4s. It
can be enabled with a new config option although don't try this with
NUMA yet (easy to fix). Note this is quite unlikely to actually do
any good on a pentium 4 because I haven't been able to test it!

The generic scheduling description works nicely on the 16 way NUMAQ
at OSDL and gives results very close to those I was getting before,
so I think I have done a good job at recreating that scheduling policy,
and the scheduling domains doesn't appear to have too much overhead.

The data structure is a bit difficult to understand. I have the start
of a paper here http://www.kerneltrap.org/~npiggin/paper.ps.gz but its
only really worth looking at for the pictures at the end for now.

Questions, comments welcome.

Nick