x86: get mp_bus_to_node early

Currently, on an amd k8 system with multi ht chains, the numa_node of
pci devices under /sys/devices/pci0000:80/* is always 0, even if that
chain is on node 1 or 2 or 3.

Workaround: pcibus_to_node(bus) is used when we want to get the node that
pci_device is on.

In struct device, we already have numa_node member, and we could use
dev_to_node()/set_dev_node() to get and set numa_node in the device.
set_dev_node is called in pci_device_add() with pcibus_to_node(bus),
and pcibus_to_node uses bus->sysdata for nodeid.

The problem is when pci_add_device is called, bus->sysdata is not assigned
correct nodeid yet. The result is that numa_node will always be 0.

pcibios_scan_root and pci_scan_root could take sysdata. So we need to get
mp_bus_to_node mapping before these two are called, and thus
get_mp_bus_to_node could get correct node for sysdata in root bus.

In scanning of the root bus, all child busses will take parent bus sysdata.
So all pci_device->dev.numa_node will be assigned correctly and automatically.

Later we could use dev_to_node(&pci_dev->dev) to get numa_node, and we
could also could make other bus specific device get the correct numa_node
too.

This is an updated version of pci_sysdata and Jeff's pci_domain patch.

[ mingo@elte.hu: build fix ]

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h
index 2207326..4793ae7 100644
--- a/include/asm-x86/topology.h
+++ b/include/asm-x86/topology.h
@@ -198,4 +198,17 @@ extern cpumask_t cpu_coregroup_map(int cpu);
 #define smt_capable()			(smp_num_siblings > 1)
 #endif
 
+#ifdef CONFIG_NUMA
+extern int get_mp_bus_to_node(int busnum);
+extern void set_mp_bus_to_node(int busnum, int node);
+#else
+static inline int get_mp_bus_to_node(int busnum)
+{
+	return 0;
+}
+static inline void set_mp_bus_to_node(int busnum, int node)
+{
+}
+#endif
+
 #endif