Re: [RFC][PATCH 03/18 v2] ftrace: Set ftrace internal functiontracing RCU safe

From: Paul E. McKenney
Date: Tue Sep 03 2013 - 10:38:19 EST


On Tue, Sep 03, 2013 at 09:22:24AM -0400, Steven Rostedt wrote:
> On Sat, 31 Aug 2013 12:44:31 -0700
> "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
>
> > On Sat, Aug 31, 2013 at 01:11:20AM -0400, Steven Rostedt wrote:
> > > From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
> > >
> > > Since none of the internal ftrace function tracing uses RCU in
> > > their callbacks, it is OK to set the global_ops (the one that
> > > they all use) to RCU safe.
> > >
> > > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> >
> > Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
>
> You must have liked this patch so much... that you acked it twice ;-)

Better safe than sorry? No, that doesn't sound quite right...

Thanx, Paul

> -- Steve
>
> >
> > > ---
> > > kernel/trace/ftrace.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> > > index d61f431..a45deaa 100644
> > > --- a/kernel/trace/ftrace.c
> > > +++ b/kernel/trace/ftrace.c
> > > @@ -1146,7 +1146,9 @@ static struct ftrace_ops global_ops = {
> > > .func = ftrace_stub,
> > > .notrace_hash = EMPTY_HASH,
> > > .filter_hash = EMPTY_HASH,
> > > - .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
> > > + .flags = FTRACE_OPS_FL_RECURSION_SAFE |
> > > + FTRACE_OPS_FL_INITIALIZED |
> > > + FTRACE_OPS_FL_RCU_SAFE,
> > > INIT_REGEX_LOCK(global_ops)
> > > };
> > >
> > > --
> > > 1.7.10.4
> > >
> > >
>

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