Re: [PATCH] [20/82] i386: Panic the system when a NUMA kernel doesn't run on IBM NUMA

["Keith Mannthey" <kmannth@gmail.com>]

On 6/23/06, Andi Kleen <ak@suse.de> wrote:
> On Saturday 24 June 2006 02:38, Dave Jones wrote:
> > On Sat, Jun 24, 2006 at 02:19:28AM +0200, Andi Kleen wrote:
> >
> >
> >  > +  extern int use_cyclone;
> >  > +  if (use_cyclone == 0) {
> >  > +          /* Make sure user sees something */
> >  > +          static const char s[] __initdata = "Not an IBM x440/NUMAQ. Don't use i386 CONFIG_NUMA anywhere else.";
> >  > +          early_printk(s);
> >  > +          panic(s);
> >  > +  }
> >
> > non-IBM Machines do still boot with that enabled though don't they?
>
>
> No they don't - as they likely didn't do before. e.g. Opterons generally
> break and that brings the point across clearer.
>
> The rationale is that CONFIG_NUMA is very rarely used on i386 (even on summit)
> and always does bitrot quickly. It also doesn't work at all on a wide
> range of machines.

I agree that i386 CONFIG_NUMA is only ment to boot on small subset of
hw but there is litte motivation to boot a numa kernel on a non-numa
box.  I am supprised that no one has enabled i386 AMD NUMA (the one
numa box that regular people have access to).

> I'm sure someone will bring up now an example where their non Summit
> machine booted with CONFIG_NUMA, but they were just extremly lucky
> and unlikely to be for very long.

Current Summit HW  (x460) dosen't use/have a cyclone.  There are
patches submitted to this list to support it's i386 NUMA boot.

Thanks,
  Keith