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

[Peter Zijlstra]

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



---
Subject: sched, numa: Fix the new NUMA topology bits
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
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@xxxxxxxxxx>
Reported-and-Tested-by: Greg Pearson <greg.pearson@xxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
 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));

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