Messages in this thread | | | Date | Tue, 3 Sep 2013 22:01:15 -0400 | From | Steven Rostedt <> | Subject | Re: [RFC][PATCH 01/18 v2] ftrace: Add hash list to save RCU unsafe functions |
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On Tue, 3 Sep 2013 18:24:04 -0700 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> > static DEFINE_PER_CPU(unsigned long, ftrace_rcu_func); > > @@ -588,15 +593,14 @@ static void > > ftrace_unsafe_callback(unsigned long ip, unsigned long parent_ip, > > struct ftrace_ops *op, struct pt_regs *pt_regs) > > { > > - int bit; > > - > > + /* Make sure we see disabled or not first */ > > + smp_rmb(); > > smp_mb__before_atomic_inc()? >
Ah, but this is before an atomic_read(), and not an atomic_inc(), thus the normal smp_rmb() is still required.
-- Steve
> > if (atomic_read(&ftrace_unsafe_rcu_disabled)) > > return; > > > > preempt_disable_notrace(); > >
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