diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 40 |
1 files changed, 34 insertions, 6 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index d26d0b095b3b..2cc409ce0a8f 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -64,6 +64,8 @@ void __init cpu_hotplug_init(void) cpu_hotplug.refcount = 0; } +cpumask_t cpu_active_map; + #ifdef CONFIG_HOTPLUG_CPU void get_online_cpus(void) @@ -291,11 +293,30 @@ int __ref cpu_down(unsigned int cpu) int err = 0; cpu_maps_update_begin(); - if (cpu_hotplug_disabled) + + if (cpu_hotplug_disabled) { err = -EBUSY; - else - err = _cpu_down(cpu, 0); + goto out; + } + + cpu_clear(cpu, cpu_active_map); + + /* + * Make sure the all cpus did the reschedule and are not + * using stale version of the cpu_active_map. + * This is not strictly necessary becuase stop_machine() + * that we run down the line already provides the required + * synchronization. But it's really a side effect and we do not + * want to depend on the innards of the stop_machine here. + */ + synchronize_sched(); + + err = _cpu_down(cpu, 0); + if (cpu_online(cpu)) + cpu_set(cpu, cpu_active_map); + +out: cpu_maps_update_done(); return err; } @@ -355,11 +376,18 @@ int __cpuinit cpu_up(unsigned int cpu) } cpu_maps_update_begin(); - if (cpu_hotplug_disabled) + + if (cpu_hotplug_disabled) { err = -EBUSY; - else - err = _cpu_up(cpu, 0); + goto out; + } + + err = _cpu_up(cpu, 0); + if (cpu_online(cpu)) + cpu_set(cpu, cpu_active_map); + +out: cpu_maps_update_done(); return err; } |