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SubjectRe: [PATCH] tracing/kprobes: Add trace event trigger invocations
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On Mon, 2014-01-06 at 11:10 -0500, Steven Rostedt wrote:
> On Sat, 28 Dec 2013 20:24:08 -0600
> Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
>
> > Add code to the kprobe/kretprobe event functions that will invoke any
> > event triggers associated with a probe's ftrace_event_file.
> >
> > The code to do this is very similar to the invocation code already
> > used to invoke the triggers associated with static events and
> > essentially replaces the existing soft-disable checks with a superset
> > that preserves the original behavior but adds the bits needed to
> > support event triggers.
> >
> > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> > ---
> > kernel/trace/trace_kprobe.c | 42 ++++++++++++++++++++++++++++++++++++------
> > 1 file changed, 36 insertions(+), 6 deletions(-)
> >
> > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> > index dae9541..1ee13eb 100644
> > --- a/kernel/trace/trace_kprobe.c
> > +++ b/kernel/trace/trace_kprobe.c
> > @@ -812,12 +812,20 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
> > struct ring_buffer *buffer;
> > int size, dsize, pc;
> > unsigned long irq_flags;
> > + unsigned long eflags;
> > + enum event_trigger_type __tt = ETT_NONE;
>
> What's the significance of the "__" in the variable?
>
> Looks as if you copied it from the ftrace_raw_event_* macro. The "__"
> there is usually recommended because it is a macro and we try to avoid
> namespace collisions by adding the "__".
>
> This is a proper function, please remove the "__" from it.
>

Right, it was just for consistency with the other invocations. Updates
to this and the syscall invocations which also do the same thing, coming
up...

Tom

> Thanks,
>
> -- Steve
>
>
> > struct ftrace_event_call *call = &tp->call;
> >
> > WARN_ON(call != ftrace_file->event_call);
> >
> > - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
> > - return;
> > + eflags = ftrace_file->flags;
> > +
> > + if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
> > + if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
> > + event_triggers_call(ftrace_file, NULL);
> > + if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
> > + return;
> > + }
> >
> > local_save_flags(irq_flags);
> > pc = preempt_count();




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