diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 143 |
1 files changed, 72 insertions, 71 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index a59cc980adad..4dc279ed3b2d 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1909,6 +1909,78 @@ void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) } EXPORT_SYMBOL(__cpuhp_remove_state); +#ifdef CONFIG_HOTPLUG_SMT +static void cpuhp_offline_cpu_device(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + + dev->offline = true; + /* Tell user space about the state change */ + kobject_uevent(&dev->kobj, KOBJ_OFFLINE); +} + +static void cpuhp_online_cpu_device(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + + dev->offline = false; + /* Tell user space about the state change */ + kobject_uevent(&dev->kobj, KOBJ_ONLINE); +} + +int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) +{ + int cpu, ret = 0; + + cpu_maps_update_begin(); + for_each_online_cpu(cpu) { + if (topology_is_primary_thread(cpu)) + continue; + ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); + if (ret) + break; + /* + * As this needs to hold the cpu maps lock it's impossible + * to call device_offline() because that ends up calling + * cpu_down() which takes cpu maps lock. cpu maps lock + * needs to be held as this might race against in kernel + * abusers of the hotplug machinery (thermal management). + * + * So nothing would update device:offline state. That would + * leave the sysfs entry stale and prevent onlining after + * smt control has been changed to 'off' again. This is + * called under the sysfs hotplug lock, so it is properly + * serialized against the regular offline usage. + */ + cpuhp_offline_cpu_device(cpu); + } + if (!ret) + cpu_smt_control = ctrlval; + cpu_maps_update_done(); + return ret; +} + +int cpuhp_smt_enable(void) +{ + int cpu, ret = 0; + + cpu_maps_update_begin(); + cpu_smt_control = CPU_SMT_ENABLED; + for_each_present_cpu(cpu) { + /* Skip online CPUs and CPUs on offline nodes */ + if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) + continue; + ret = _cpu_up(cpu, 0, CPUHP_ONLINE); + if (ret) + break; + /* See comment in cpuhp_smt_disable() */ + cpuhp_online_cpu_device(cpu); + } + cpu_maps_update_done(); + return ret; +} +#endif + #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) static ssize_t show_cpuhp_state(struct device *dev, struct device_attribute *attr, char *buf) @@ -2063,77 +2135,6 @@ static const struct attribute_group cpuhp_cpu_root_attr_group = { #ifdef CONFIG_HOTPLUG_SMT -static void cpuhp_offline_cpu_device(unsigned int cpu) -{ - struct device *dev = get_cpu_device(cpu); - - dev->offline = true; - /* Tell user space about the state change */ - kobject_uevent(&dev->kobj, KOBJ_OFFLINE); -} - -static void cpuhp_online_cpu_device(unsigned int cpu) -{ - struct device *dev = get_cpu_device(cpu); - - dev->offline = false; - /* Tell user space about the state change */ - kobject_uevent(&dev->kobj, KOBJ_ONLINE); -} - -int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) -{ - int cpu, ret = 0; - - cpu_maps_update_begin(); - for_each_online_cpu(cpu) { - if (topology_is_primary_thread(cpu)) - continue; - ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); - if (ret) - break; - /* - * As this needs to hold the cpu maps lock it's impossible - * to call device_offline() because that ends up calling - * cpu_down() which takes cpu maps lock. cpu maps lock - * needs to be held as this might race against in kernel - * abusers of the hotplug machinery (thermal management). - * - * So nothing would update device:offline state. That would - * leave the sysfs entry stale and prevent onlining after - * smt control has been changed to 'off' again. This is - * called under the sysfs hotplug lock, so it is properly - * serialized against the regular offline usage. - */ - cpuhp_offline_cpu_device(cpu); - } - if (!ret) - cpu_smt_control = ctrlval; - cpu_maps_update_done(); - return ret; -} - -int cpuhp_smt_enable(void) -{ - int cpu, ret = 0; - - cpu_maps_update_begin(); - cpu_smt_control = CPU_SMT_ENABLED; - for_each_present_cpu(cpu) { - /* Skip online CPUs and CPUs on offline nodes */ - if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) - continue; - ret = _cpu_up(cpu, 0, CPUHP_ONLINE); - if (ret) - break; - /* See comment in cpuhp_smt_disable() */ - cpuhp_online_cpu_device(cpu); - } - cpu_maps_update_done(); - return ret; -} - - static ssize_t __store_smt_control(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) |