On Tue, Jun 16, 2015 at 02:57:44PM -0400, Steven Rostedt wrote: > On Tue, 16 Jun 2015 10:39:42 -0700 > "Paul E. McKenney" <[email protected]> wrote: > > > > >>If rcu_is_watching() and __rcu_is_watching() are both marked as > > > >>notrace, it makes sense to use preempt_disable/enable_notrace() as it > > > >>otherwise defeats the purpose of the notrace markers on rcu_is_watching. > > > > And __rcu_is_watching() is marked notrace as well. > > Isn't that what I said?
You did say "if", so I checked. ;-) > > > >>That is regardless of what the rest of this thread is about. > > > > > > > >Good enough! Alexei, are you OK with my adding your Signed-off-by > > > >to the above patch? > > > > > > sure. > > > Signed-off-by: Alexei Starovoitov <[email protected]> > > > > > > >(Still not sold on reentrant call_rcu() and > > > >kfree_rcu(), but getting notrace set up correctly is worthwhile.) > > > > > > I'm not sold on it either. So far trying to understand > > > all consequences. > > > > Here is the updated patch. Steven, I added your "Acked-by" based > > on your positive comments above, please let me know if you would > > like me to remove it. > > I'm fine with it. But doesn't Acked-by go above Signed-off-by? I have done it both ways, usually in time order. Thanx, Paul > -- Steve > > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 9611f225d383a2edbdf74ca7f00c8d0b1e56dc45 > > Author: Alexei Starovoitov <[email protected]> > > Date: Tue Jun 16 10:35:18 2015 -0700 > > > > rcu: Make rcu_is_watching() really notrace > > > > Although rcu_is_watching() is marked notrace, it invokes > > preempt_disable() > > and preempt_enable(), both of which can be traced. This defeats the > > purpose of the notrace on rcu_is_watching(), so this commit substitutes > > preempt_disable_notrace() and preempt_enable_notrace(). > > > > Signed-off-by: Alexei Starovoitov <[email protected]> > > Signed-off-by: Paul E. McKenney <[email protected]> > > Acked-by: Steven Rostedt <[email protected]> > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index fc0385380e97..c844ef3c2fae 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -973,9 +973,9 @@ bool notrace rcu_is_watching(void) > > { > > bool ret; > > > > - preempt_disable(); > > + preempt_disable_notrace(); > > ret = __rcu_is_watching(); > > - preempt_enable(); > > + preempt_enable_notrace(); > > return ret; > > } > > EXPORT_SYMBOL_GPL(rcu_is_watching); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
