https://bugzilla.kernel.org/show_bug.cgi?id=72051

            Bug ID: 72051
           Summary: Failed to correctly detect device numa_node
                    information on AMD systems
           Product: ACPI
           Version: 2.5
    Kernel Version: 3.14-rc4
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
          Assignee: acpi_ot...@kernel-bugs.osdl.org
          Reporter: suravee.suthikulpa...@amd.com
        Regression: No

This bug affects AMD family 12h and newer.

The device numa_node information in the sysfs for each PCI device (e.g.
/devices/pci0000:50/0000:50:00.2/numa_node) is showing value -1.

In file arch/x86/pci/acpi.c, in function pci_acpi_scan_root(), it is
queries the node information as following:

#ifdef CONFIG_ACPI_NUMA
      pxm = acpi_get_pxm(device->handle);
      if (pxm >= 0)
          node = pxm_to_node(pxm);
      if (node != -1)
          set_mp_bus_to_node(busnum, node);
      else
#endif
          node = get_mp_bus_to_node(busnum);

In this case, I see that the acpi_get_pxm() returns -1.  Therefore, it
falls back to using the node information in mp_bus_to_node[].  For AMD systems,
the arch/x86/pci/amd_bus.c only probe the hostbridge for family10h and 11h, and
showing the correct numa_node information.  For the newer systems, it does not
fill the mp_bus_to_node[], and result in the value -1.

Please refer to the following email thread for more information:
http://marc.info/?l=linux-kernel&m=139405365524526&w=2

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