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

From: Keith Mannthey
Date: Fri Jun 23 2006 - 21:02:48 EST


On 6/23/06, Andi Kleen <ak@xxxxxxx> 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
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