path: root/arch
diff options
authorVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>2013-03-22 05:49:35 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-11 07:18:17 -0700
commitf63a3b86960177bca59f29eb5c71e3c2fb3e91aa (patch)
tree99284e700ba909fc24576bf23bd10f2c5dd25421 /arch
parent4a32fbd0b67057a94dbd173ed85114aa46e32dfb (diff)
powerpc: fix numa distance for form0 device tree
commit 7122beeee7bc1757682049780179d7c216dd1c83 upstream. The following commit breaks numa distance setup for old powerpc systems that use form0 encoding in device tree. commit 41eab6f88f24124df89e38067b3766b7bef06ddb powerpc/numa: Use form 1 affinity to setup node distance Device tree node /rtas/ibm,associativity-reference-points would index into /cpus/PowerPCxxxx/ibm,associativity based on form0 or form1 encoding detected by ibm,architecture-vec-5 property. All modern systems use form1 and current kernel code is correct. However, on older systems with form0 encoding, the numa distance will get hard coded as LOCAL_DISTANCE for all nodes. This causes task scheduling anomaly since scheduler will skip building numa level domain (topmost domain with all cpus) if all numa distances are same. (value of 'level' in sched_init_numa() will remain 0) Prior to the above commit: ((from) == (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE) Restoring compatible behavior with this patch for old powerpc systems with device tree where numa distance are encoded as form0. Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index bba87ca2b4d..6a252c468d6 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -201,7 +201,7 @@ int __node_distance(int a, int b)
int distance = LOCAL_DISTANCE;
if (!form1_affinity)
- return distance;
+ return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);
for (i = 0; i < distance_ref_points_depth; i++) {
if (distance_lookup_table[a][i] == distance_lookup_table[b][i])