On Monday, January 20, 2014 10:31:54 AM Jiang Liu wrote:
> 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@xxxxxxxxxxxxxxx>
I wonder what the status here is? Did this patch go anywhere?
> ---
> 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);
> + }
> #endif
> }
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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