> #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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>