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

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Date:	Fri, 17 Apr 2009 12:01:55 +0200
From:	Andreas Herrmann <andreas.herrmann3@....com>
To:	jbarnes@...tuousgeek.org
CC:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH]  pci: derive nearby CPUs from device's instead of bus'
	NUMA information

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@...en:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
  0
  root@...en:/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@...en:/sys/devices/pci0000:00/0000:00:1a.4# cat numa_node
  2
  root@...en:/sys/devices/pci0000:00/0000:00:1a.4# cat local_cpu*
  8-11
  00000000,00000f00

Signed-off-by: Andreas Herrmann <andreas.herrmann3@....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



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