[Patch v1] ACPI, x86: fix bug in associating hot-added CPUs with corresponding NUMA node

From: Jiang Liu
Date: Sun Jan 19 2014 - 21:31:13 EST

Current ACPI cpu hotplug driver fails to associate hot-added CPUs with
corresponding NUMA node when doing socket online. The code path to
associate CPU with NUMA node is as below:

When doing socket online, a new NUMA node is introduced in addition to
hot-added CPU and memory device. And the new NUMA node is marked as
online when onlining hot-added CPUs through sysfs interface

On the other hand, acpi_map_cpu2node() will only build the CPU to node
map if corresponding NUMA node is already online, so it always fails
to associate hot-added CPUs with corresponding NUMA node because the
NUMA node is still in offline state.

For the fix, we could safely remove the "node_online(node)" check in
function acpi_map_cpu2node() because it's only called for hot-added CPUs
by acpi_processor_hotadd_init().

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
arch/x86/kernel/acpi/boot.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 6c0b43b..7625de9 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -614,10 +614,10 @@ static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
int nid;

nid = acpi_get_node(handle);
- if (nid == -1 || !node_online(nid))
- return;
- set_apicid_to_node(physid, nid);
- numa_set_node(cpu, nid);
+ if (nid != -1) {
+ set_apicid_to_node(physid, nid);
+ numa_set_node(cpu, nid);
+ }


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