diff options
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r-- | kernel/cpu.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 0a004131..f43c8f3 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -84,6 +84,14 @@ struct hotplug_pcp { int grab_lock; struct completion synced; #ifdef CONFIG_PREEMPT_RT_FULL + /* + * Note, on PREEMPT_RT, the hotplug lock must save the state of + * the task, otherwise the mutex will cause the task to fail + * to sleep when required. (Because it's called from migrate_disable()) + * + * The spinlock_t on PREEMPT_RT is a mutex that saves the task's + * state. + */ spinlock_t lock; #else struct mutex mutex; |