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 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.
> 
> Well, since ULE and UMA are the only two subsystems which make use of
> mp_maxid, can I request that it be one over the maximum id so that I can
> use it in loops like:
> for (i = 0; i < mp_maxid; i++) {
> 
> Otherwise I guess I can do <=.  If you fix x86, can you fix alpha and
> amd64, and uma and ule? :-)

I'll fix all of them and work up a patch tomorrow, sure. :)

-- 

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