[PATCH] pci: derive nearby CPUs from device's instead of bus' NUMA information

Andreas Herrmann
2009-04-17T10:02:40Z

In case of AMD CPU northbridge functions this NUMA information might
differ.

Here is an example from a 4-socket system.

Currently Linux shows

root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
0
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat local_cpu*
0-3
00000000,0000000f

which is not correct for northbridge functions as the local CPUs
are those of the same socket.

With this patch and a quirk for AMD CPU NB functions Linux can
do better and correctly show

root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
2
root@hagen:/sys/devices/pci0000:00/0000:00:1a.4# cat local_cpu*
8-11
00000000,00000f00

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
drivers/pci/pci-sysfs.c | 8 ++++++++
1 files changed, 8 insertions(+), 0 deletions(-)

The quirk for AMD CPU NB functions is contained in another patch
that I'll send to x86-maintainers for inclusion into tip tree.

Please apply.

Thanks,
Andreas

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index a7eb1b4..9360f3d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -74,7 +74,11 @@ static ssize_t local_cpus_show(struct device *dev,
const struct cpumask *mask;
int len;

+#ifdef CONFIG_NUMA
+ mask = cpumask_of_node(dev_to_node(dev));
+#else
mask = cpumask_of_pcibus(to_pci_dev(dev)->bus);
+#endif
len = cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
buf[len++] = '\n';
buf[len] = '\0';
@@ -88,7 +92,11 @@ static ssize_t local_cpulist_show(struct device *dev,
const struct cpumask *mask;
int len;

+#ifdef CONFIG_NUMA
+ mask = cpumask_of_node(dev_to_node(dev));
+#else
mask = cpumask_of_pcibus(to_pci_dev(dev)->bus);
+#endif
len = cpulist_scnprintf(buf, PAGE_SIZE-2, mask);
buf[len++] = '\n';
buf[len] = '\0';
--
1.6.2