Messages in this thread | | | Date | Fri, 11 Jul 2014 11:30:10 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] rcu: define tracepoint strings only if CONFIG_TRACING is set |
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On Fri, 11 Jul 2014 08:12:40 -0700 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> On Fri, Jul 11, 2014 at 01:38:12PM +0200, Ard Biesheuvel wrote: > > Commit f7f7bac9cb1c ("rcu: Have the RCU tracepoints use the tracepoint_string > > infrastructure") unconditionally populates the __tracepoint_str input section, > > but this section is not assigned an output section if CONFIG_TRACING is not set. > > This results in the __tracepoint_str turning up in unexpected places, i.e., > > after _edata. > > > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > Cc: rostedt@goodmis.org > > Cc: dipankar@in.ibm.com > > Cc: paulmck@linux.vnet.ibm.com > > If you get a Reviewed-by from Steven Rostedt, I will be happy to queue > this one.
I'm fine with it, but it should add a comment.
> > Thanx, Paul > > > --- > > kernel/rcu/tree.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > index f1ba77363fbb..ac1984149eb5 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -79,9 +79,16 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS]; > > * the tracing userspace tools to be able to decipher the string > > * address to the matching string. > > */ > > +#ifdef CONFIG_TRACING
/* * When tracing is enabled, DEFINE_TPS() will export the string to * userspace via the tracing debugfs directory. This allows userspace * tools to read the binary tracepoints that reference the pointer * to the string and not the string itself. */
> > +#define DEFINE_TPS(sname) \ > > +static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; > > +#else > > +#define DEFINE_TPS(sname) > > +#endif
Also, perhaps we should call it:
DEFINE_RCU_TPS()
Other than that, I'm fine with the patch.
I'll review v2 ;-)
-- Steve
> > + > > #define RCU_STATE_INITIALIZER(sname, sabbr, cr) \ > > static char sname##_varname[] = #sname; \ > > -static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname; \ > > +DEFINE_TPS(sname) \ > > struct rcu_state sname##_state = { \ > > .level = { &sname##_state.node[0] }, \ > > .call = cr, \ > > -- > > 1.8.3.2 > >
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