x86, acpi: Fix bug in associating hot-added CPUs with corresponding NUMA node

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:
acpi_processor_add()
    ->acpi_processor_get_info()
	->acpi_processor_hotadd_init()
	    ->acpi_map_lsapic()
		->_acpi_map_lsapic()
		    ->acpi_map_cpu2node()
cpu_subsys_online()
    ->try_online_node()
	->node_set_online()

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
/sys/devices/system/cpu/cpuxx/online.

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@linux.intel.com>
Link: http://lkml.kernel.org/r/1390185115-26850-1-git-send-email-jiang.liu@linux.intel.com
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 1dac94265b5978282262b77d4f496ae512701eb8..9f46f2b1cfc2d528507dbb2986a30aacf44e2c8e 100644 (file)
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -613,10 +613,10 @@ 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);
+       }
 #endif
 }