Rotating Staircase DeadLine scheduler for -mm

What follows this email is a series of patches for the RSDL cpu scheduler as found in 2.6.21-rc3-mm1. This series is for 2.6.21-rc3-mm2 and has some bugfixes for the issues found so far. While it is not clear that I've attended to all the bugs, it is worth noting that a complete rewrite is a teensy bit more than a trivial change shall we say ;)

akpm it still has trouble on that monster config of yours but there's so much else going on in this -mm I don't know what to make of it. getting ppc to work on qemu was more work than I thought and I haven't succeeded there yet either :|

A rolled up patch can be found here:
http://ck.kolivas.org/patches/staircase-deadline/2.6.21-rc3-mm2-rsdl.patch

Patch series here:
http://ck.kolivas.org/patches/staircase-deadline/2.6.21-rc3-mm2/

and the patch series will follow. If time permits I will make available a newer version for the older kernels soon.

Changelog:
- Made it possible for the idle task to schedule on cpu_hotplug.
- Fixed the accounting across fork()
- Recalculation of priority for tasks that have already run this major rotation and are now on the expired array was wrong. It has been corrected.
- The bitmap error that has been hit on some architectures was made more verbose to make it clear that something has gone wrong, and will keep going off if the problem persists.

-ck

Oh and if it wasn't clear from this message. It still needs work to be bug free and probably shouldn't be part of -mm till I've ironed out all the oopsen. Thanks.

-ck