On Thu, 2013-06-27 at 05:52 +0200, Mike Galbraith wrote: > On Wed, 2013-06-26 at 15:28 -0400, Steven Rostedt wrote: > > > @@ -2491,6 +2491,31 @@ static inline int rcu_blocking_is_gp(voi > > return ret; > > } > > > > +#ifdef CONFIG_PREEMPT_RT_FULL > > +DEFINE_LOCAL_IRQ_LOCK(rcu_sched_lock); > > +/* > > + * Real-time allows for synchronize sched to sleep but not migrate. > > + * This is done via the local locks. When calling synchronize_sched(), > > + * all the local locks need to be taken and released. This will ensure > > + * that all users of rcu_read_lock_sched() will be out of their critical > > + * sections at the completion of this function. synchronize_sched() will > > + * still perform the normal RCU sched operations to synchronize with > > + * locations that use disabling preemption or interrupts. > > + */ > > +static void rcu_synchronize_sched_rt(void) > > +{ > > + int cpu; > > + > > + for_each_possible_cpu(cpu) { > > + spin_lock(&per_cpu(rcu_sched_lock, cpu).lock); > > + spin_unlock(&per_cpu(rcu_sched_lock, cpu).lock); > > + } > > +} > > Does that have to be possible vs online? No, I was doing the "paranoid" approach, as I didn't know how much hotplug may be using synchronize_sched() and wanted to make sure I hit all CPUs. But I think online would be sufficient. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html