On Sat, Apr 27, 2013 at 02:32:48PM +0300, Julian Anastasov wrote: > > Hello, > > On Fri, 26 Apr 2013, Eric Dumazet wrote: > > > On Fri, 2013-04-26 at 10:48 -0700, Paul E. McKenney wrote: > > > > > Don't get me wrong, I am not opposing cond_resched_rcu_lock() because it > > > will be difficult to validate. For one thing, until there are a lot of > > > them, manual inspection is quite possible. So feel free to apply my > > > Acked-by to the patch. > > > > One question : If some thread(s) is(are) calling rcu_barrier() and > > waiting we exit from rcu_read_lock() section, is need_resched() enough > > for allowing to break the section ? > > > > If not, maybe we should not test need_resched() at all. > > > > rcu_read_unlock(); > > cond_resched(); > > rcu_read_lock(); > > So, I assume, to help realtime kernels and rcu_barrier > it is not a good idea to guard rcu_read_unlock with checks. > I see that rcu_read_unlock will try to reschedule in the > !CONFIG_PREEMPT_RCU case (via preempt_enable), can we > use ifdefs to avoid double TIF_NEED_RESCHED check?: > > rcu_read_unlock(); > #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_RCU) I would instead suggest something like: #ifndef CONFIG_PREEMPT_RCU But yes, in the CONFIG_PREEMPT_RCU case, the cond_resched() is not needed. Thanx, Paul > cond_resched(); > #endif > rcu_read_lock(); > > Regards > > -- > Julian Anastasov <ja@xxxxxx> > -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
