[patch] O(1) scheduler, -H6

[Ingo Molnar]

the -H6 patch is available:

    http://redhat.com/~mingo/O(1)-scheduler/sched-O1-2.5.2-pre11-H6.patch
    http://redhat.com/~mingo/O(1)-scheduler/sched-O1-2.4.17-H6.patch

the most important fix is from DaveM, we should not send an IPI to
ourselves. That fix was the last bug on Sparc boxes it appears.

overall stability status: all the previous bug reports about runtime
lockups (which happen in -pre11 as well) are fixed in this patchset. The
only open issue is the boot-time lockup some people are seeing with the
2.4 patch only (not the 2.5 patch), there is a chance that it's fixed in
this patch too.

Changes:

 - DaveM's the man: check for p->cpu != smp_processor_id() before doing a
   smp_send_reschedule(p->cpu). Doh!

 - task_interactive() test is done properly now - the H5 would mis-detect
   every nice +19 task as interactive. I'd like to ask everyone who had
   interactivity problems to re-test under -H6. It's all very smooth on my
   systems.

 - Rusty Russell: add comment to expire_task.

 - fix main.c in the 2.4.17 patch. (this should fix the bootup-lockups.)

Bug reports, comments, suggestions welcome. (any patch/fix that is not in
-H6 has gone lost in my mailqueue. The influx is rather high.)

	Ingo