Re: Commit cb83b62 fails to boot with a divide by zero error.

[Robin Holt <holt@sgi.com>]

On Fri, May 11, 2012 at 04:33:10PM +0200, Peter Zijlstra wrote:
> On Fri, 2012-05-11 at 08:39 -0500, Robin Holt wrote:
> 
> > We found that reverting the commit:
> > cb83b62 (x86/sched/core) sched/numa: Rewrite the CONFIG_NUMA sched domain support
> > 
> > also got things working.
> 
> there's a particularly stupid bug in that code

Even with that applied, I still get the divide by zero.

Robin

> 
> 
> 
> ---
> Subject: sched, numa: Fix the new NUMA topology bits
> From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date: Fri May 11 00:56:20 CEST 2012
> 
> There's no need to convert a node number to a node number by
> pretending its a cpu number..
> 
> Reported-by: Yinghai Lu <yinghai@kernel.org>
> Reported-and-Tested-by: Greg Pearson <greg.pearson@hp.com>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
>  kernel/sched/core.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -6378,8 +6378,7 @@ static void sched_init_numa(void)
>  			sched_domains_numa_masks[i][j] = mask;
>  
>  			for (k = 0; k < nr_node_ids; k++) {
> -				if (node_distance(cpu_to_node(j), k) >
> -						sched_domains_numa_distance[i])
> +				if (node_distance(j, k) > sched_domains_numa_distance[i])
>  					continue;
>  
>  				cpumask_or(mask, mask, cpumask_of_node(k));