tracing/kprobes: Add a helper method to return number of probe hits

The number of probe hits is stored in a percpu variable and therefore
can't be read directly. Add a helper method trace_kprobe_nhit() that
performs the required calculation.

It will be used in a follow-up commit that changes kprobe selftests to
verify the number of probe hits.

Link: http://lkml.kernel.org/r/1481293178-3128-1-git-send-email-marcin.nowakowski@imgtec.com

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Marcin Nowakowski 2016-12-09 15:19:37 +01:00 committed by Steven Rostedt
parent 99e6f6e813
commit f18f97ac43

View File

@ -73,6 +73,17 @@ static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
return !!strchr(trace_kprobe_symbol(tk), ':');
}
static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
{
unsigned long nhit = 0;
int cpu;
for_each_possible_cpu(cpu)
nhit += *per_cpu_ptr(tk->nhit, cpu);
return nhit;
}
static int register_kprobe_event(struct trace_kprobe *tk);
static int unregister_kprobe_event(struct trace_kprobe *tk);
@ -882,14 +893,10 @@ static const struct file_operations kprobe_events_ops = {
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
struct trace_kprobe *tk = v;
unsigned long nhit = 0;
int cpu;
for_each_possible_cpu(cpu)
nhit += *per_cpu_ptr(tk->nhit, cpu);
seq_printf(m, " %-44s %15lu %15lu\n",
trace_event_name(&tk->tp.call), nhit,
trace_event_name(&tk->tp.call),
trace_kprobe_nhit(tk),
tk->rp.kp.nmissed);
return 0;