On Mon, 2013-06-10 at 15:10 -0700, Paul E. McKenney wrote: > > So maybe that patch was a winner after all and got dropped ? > > Please see below for the patch that I was thinking of. > > It has not been dropped, I was on travel and a bit slow about pushing > things. > > Thanx, Paul > > ------------------------------------------------------------------------ > > trace: Allow idle-safe tracepoints to be called from irq > > __DECLARE_TRACE_RCU() currently creates an _rcuidle() tracepoint which > may safely be invoked from what RCU considers to be an idle CPU. > However, these _rcuidle() tracepoints may -not- be invoked from the > handler of an irq taken from idle, because rcu_idle_enter() zeroes > RCU's nesting-level counter, so that the rcu_irq_exit() returning to > idle will trigger a WARN_ON_ONCE(). > > This commit therefore substitutes rcu_irq_enter() for rcu_idle_exit() > and rcu_irq_exit() for rcu_idle_enter() in order to make the _rcuidle() > tracepoints usable from irq handlers as well as from process context. > > Reported-by: Dave Jones <[email protected]> > Signed-off-by: Paul E. McKenney <[email protected]> > Cc: Steven Rostedt <[email protected]> > > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h > index 2f322c3..f8e084d 100644 > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -145,8 +145,8 @@ static inline void tracepoint_synchronize_unregister(void) > TP_PROTO(data_proto), \ > TP_ARGS(data_args), \ > TP_CONDITION(cond), \ > - rcu_idle_exit(), \ > - rcu_idle_enter()); \ > + rcu_irq_enter(), \ > + rcu_irq_exit()); \
Still wont fix the splat that Dave saw. As the splat has nothing to do with tracepoints, but has to do with function tracing, which is a whole 'nother beast. -- Steve > } > #else > #define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) -- 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/
