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

KOSAKI Motohiro
2013-04-18T16:33:20Z

> #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?

> 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.

> + 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.