[o(1) sched J0] higher priority smaller timeslices, in fact

[Alexei Podtelezhnikov]

The comment and the actual macros are inconsistent.
positive number * (19-n) is a decreasing function of n!

+ * The higher a process's priority, the bigger timeslices
+ * it gets during one round of execution. But even the lowest
+ * priority process gets MIN_TIMESLICE worth of execution time.
+ */

-#define NICE_TO_TIMESLICE(n)   (MIN_TIMESLICE + \
-	((MAX_TIMESLICE - MIN_TIMESLICE) * (19 - (n))) / 39)
+#define NICE_TO_TIMESLICE(n) (MIN_TIMESLICE + \
+	((MAX_TIMESLICE - MIN_TIMESLICE) * (19-(n))) / 39)

I still suggest a different set as faster and more readable at least to 
me. Just two operations instead of 4!

#define NICE_TO_TIMESLICE(n) (((n)+21)*(HZ/10))  // should be positive!
#define MAX_TIMESLICE  NICE_TO_TIMESLICE(19)
#define MIN_TIMESLICE  NICE_TO_TIMESLICE(-20)

with later tweaking done in the function, like (((n)+22)*(HZ/25)) instead.

Alexei