Messages in this thread | | | Date | Wed, 3 Jun 2009 23:48:17 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v2][GIT PULL] tracing: add trace_stack interface |
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On Tue, May 19, 2009 at 09:09:40PM -0400, Steven Rostedt wrote: > > Ingo, > > I rebased because I forgot to add EXPORT_SYMBOL_GPL. > > -- Steve > > Please pull the latest tip/tracing/ftrace tree, which can be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git > tip/tracing/ftrace > > > Steven Rostedt (1): > tracing: add trace_stack interface > > ---- > include/linux/kernel.h | 2 ++ > kernel/trace/trace.c | 16 ++++++++++++++++ > 2 files changed, 18 insertions(+), 0 deletions(-) > --------------------------- > commit 9f6b28655254b91c48f684b367ac14bfec0e180a > Author: Steven Rostedt <srostedt@redhat.com> > Date: Tue May 19 18:54:16 2009 -0400 > > tracing: add trace_stack interface > > This patch adds the global function > > void trace_stack(void) > > This allows a developer to find where a function is called. For example, > if you want to know who calls __netif_reschedule, you can add > > static inline void __netif_reschedule(struct Qdisc *q) > { > struct softnet_data *sd; > unsigned long flags; > > + trace_stack(); > local_irq_save(flags); > sd = &__get_cpu_var(softnet_data); > q->next_sched = sd->output_queue; > > And see the following in the trace output: > > <= __ftrace_trace_stack > <= trace_stack > <= __netif_schedule > <= dev_watchdog > <= run_timer_softirq > <= __do_softirq > <= call_softirq > <= do_softirq > <= irq_exit > > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I wanted to use it to get the recursive locking points in reiserfs but I can't find it.
Has it been merged in -tip ?
Thanks.
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index 883cd44..347a0f1 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -511,6 +511,7 @@ extern int > __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap); > > extern void ftrace_dump(void); > +extern void trace_stack(void); > #else > static inline void > ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { } > @@ -531,6 +532,7 @@ ftrace_vprintk(const char *fmt, va_list ap) > return 0; > } > static inline void ftrace_dump(void) { } > +static inline void trace_stack(void) { } > #endif /* CONFIG_TRACING */ > > /* > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index dd40d23..7bfd4f2 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -1046,6 +1046,22 @@ void __trace_stack(struct trace_array *tr, > __ftrace_trace_stack(tr, flags, skip, pc); > } > > +/** > + * trace_stack - dump the stack into the trace buffer > + * > + * Use this to record the stack trace into the ring buffer. If you > + * want to know a caller of a function, place a call to trace_stack > + * and the ftrace trace file will display who the callers were. > + */ > +void trace_stack(void) > +{ > + unsigned long flags; > + > + local_save_flags(flags); > + __trace_stack(&global_trace, flags, 0, preempt_count()); > +} > +EXPORT_SYMBOL_GPL(trace_stack); > + > static void ftrace_trace_userstack(struct trace_array *tr, > unsigned long flags, int pc) > { > >
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