cvs commit: src/sys/alpha/alpha mp_machdep.c

[John Baldwin]

On 01-Dec-2003 Jeff Roberson wrote:
> On Mon, 1 Dec 2003, John Baldwin wrote:
> 
>>
>> On 30-Nov-2003 Jeff Roberson wrote:
>> > jeff        2003/11/30 14:08:24 PST
>> >
>> >   FreeBSD src repository
>> >
>> >   Modified files:
>> >     sys/alpha/alpha      mp_machdep.c
>> >   Log:
>> >    - Set mp_maxid in a way that is consistent with every other arch.  It is
>> >      one more than the last valid 'cpuid'.
>> >
>> >   Approved by:    re (rwatson)
>>
>> Eh?  No it's not.  All that needs to be true is that for every processor,
>> PCPU_GET(cpuid) <= mp_maxid.
>>
>> It can be equal to the highest ID and should be so for most cases.
> 
> From x86's mp_machdep:
>         mp_maxid = MAXCPU;

That's a bug.

> ia64
> mp_maxid = min(mp_ncpus, MAXCPU) - 1;

This is correct.  Note - 1.

> sparc64
>         cpus = 0;
>         root = OF_peer(0);
>         for (child = OF_child(root); child != 0; child = OF_peer(child)) {
>                 if (OF_getprop(child, "device_type", buf, sizeof(buf)) > 0
> &&
>                     strcmp(buf, "cpu") == 0)
>                         cpus++;
>         }
>         mp_maxid = cpus;

This should be cpus - 1.

> And I just changed amd64 and alpha to mean maxid + 1.  Damn. it looks like
> just sparc64 and x86 were wrong.  Maybe I should change those to mean the
> right thing, and backout the changes to uma.  yack.

Heh.  I am already waiting for approval from re@ to fix x86.  That was
definitely my bug.

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/