2.6.0-test3-mm1 interactivity scheduling mistakes (smp)

[Helge Hafting <helgehaf@aitel.hist.no>]

I ran a "nice make -j3 bzImage" on 2.6.9-test3-mm1 in order
to compile 2.6.0-test3-mm2 on my dual celeron.

While waiting I played cuyo, a lightweight game similiar to tetris.

This mostly behaved as expected, with a responsive game.
But mozilla (on some other virtual desktop) occationally
refreshed its page, causing several seconds with jerky response
in the game.

This is wrong for two reasons:
1. There should be enough cpu with two processors,
   one running the game and another the heavy mozilla stuff.
   The make was niced after all.  No guessing, I told it explicitly.

2. The game has very interactive behaviour, it uses  4-10% cpu
   and cause X to use about 20%.  Mozilla may have been idle for a 
   while, getting "interactive".  But it shouldn't remain
   interactive  for so long,  it sat at 100% till it went
   idle again.   

X runs with elevated priority, (std. debian testing setup)
but that shouldn't matter - X only used 20% and that was
for the game and two xterms.  Mozilla wasn't visible
at all.

Helge Hafting