Re: [Bug fix PATCH] numa, cpu hotplug: Change links of CPU and node when changing node number by onlining CPU

Yasuaki Ishimatsu
2013-04-19T01:17:46Z

2013/04/19 1:32, KOSAKI Motohiro wrote:
>> #ifdef CONFIG_HOTPLUG_CPU
>> +static void change_cpu_under_node(struct cpu *cpu,
>> + unsigned int from_nid, unsigned int to_nid)
>> +{
>> + int cpuid = cpu->dev.id;
>> + unregister_cpu_under_node(cpuid, from_nid);
>> + register_cpu_under_node(cpuid, to_nid);
>> + cpu->node_id = to_nid;
>> +}
>> +
>

> Where is stub for !CONFIG_HOTPLUG_CPU?

This function is called by only store_online(). And the store_online() is
defined only when CONFIG_HOTPLUG_CPU enables. Thus change_cpu_under_node()
is not necessary for !CONFIG_HOTPLUG_CPU.

>
>
>> static ssize_t show_online(struct device *dev,
>> struct device_attribute *attr,
>> char *buf)
>> @@ -39,17 +48,23 @@ static ssize_t __ref store_online(struct device *dev,
>> const char *buf, size_t count)
>> {
>> struct cpu *cpu = container_of(dev, struct cpu, dev);
>> + int num = cpu->dev.id;
>

> "num" is wrong name. cpuid may be better.

I'll update it.

>
>
>> + int from_nid, to_nid;
>> ssize_t ret;
>>
>> cpu_hotplug_driver_lock();
>> switch (buf[0]) {
>> case '0':
>> - ret = cpu_down(cpu->dev.id);
>> + ret = cpu_down(num);
>> if (!ret)
>> kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
>> break;
>> case '1':
>> - ret = cpu_up(cpu->dev.id);
>> + from_nid = cpu_to_node(num);
>> + ret = cpu_up(num);
>> + to_nid = cpu_to_node(num);
>> + if (from_nid != to_nid)
>> + change_cpu_under_node(cpu, from_nid, to_nid);
>
> You need to add several comments. this code is not straightforward.

O.K. I'll update it.

Thanks,
Yasuaki Ishimatsu