Hi Asok,
I went and grepped the kernel and had a look in
arch/ia64/kernel/sys_ia64.c to see how the return value is used.
Interestingly the function is used on the alpha, ia64 and mips but not on
a standard i386! :) and it turns the return value back into the nice value
correctly.
asmlinkage long
ia64_getpriority (int which, int who, long arg2, long arg3, long arg4,
long arg5, long arg6,
long arg7, long stack)
{
struct pt_regs *regs = (struct pt_regs *) &stack;
extern long sys_getpriority (int, int);
long prio;
prio = sys_getpriority(which, who);
if (prio >= 0) {
regs->r8 = 0; /* ensure negative priority is not
mistaken as error code */
prio = 20 - prio;
}
return prio;
}
I guess it's a matter of as long as both party's are talking the same
protocol.
mick
On Wed, 12 Dec 2001, Asok Tiyyagura wrote:
> Michael,
>
> I beleive -20 is the highest priority process while 19
> is the lowest priority process i.e, priority rule is
> "smaller the number higher the priority"
>
> i.e, in my case
> -20 ==> -20 + 20 = 0
> -19 ==> -19 + 20 = 1
> .....
> ..
> 18 ==> 18 + 20 = 38
> 19 ==> 19 + 20 = 39
>
> We "prevent" the priority rule in this mapping. In the
> current code...
>
> -20 ===> 20 - (-20) = 40
> -19 ===> 20 - (-19) = 39
> -18 ===> 20 - (-18) = 38
> ....
>
> 19 ===> 20 - 19 = 1
>
> This mapping violates the "priority rule". While I
> correct my earlier statement from
>
> niceval = 20 + p->nice to
> niceval = 21 + p->niceval (Just to make sure it indeed
> ranges from 1-40 )I still beleive it should be "+"
> instead of "-".
>
> --Asok
>
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