Timeslice proportion has been increased substantially for -niced tasks.  As
a result of this kernel threads have much larger timeslices than they
previously had.

Change kernel threads' nice value to -5 to bring their timeslice back in
line with previous behaviour.  This means kernel threads will be less
likely to cause large latencies under periods of system stress for normal
nice 0 tasks.

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>