tracing: add support for userspace stacktraces in tracing/iter_ctrl
Impact: add new (default-off) tracing visualization feature
Usage example:
mount -t debugfs nodev /sys/kernel/debug
cd /sys/kernel/debug/tracing
echo userstacktrace >iter_ctrl
echo sched_switch >current_tracer
echo 1 >tracing_enabled
.... run application ...
echo 0 >tracing_enabled
Then read one of 'trace','latency_trace','trace_pipe'.
To get the best output you can compile your userspace programs with
frame pointers (at least glibc + the app you are tracing).
Signed-off-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index b106fd8..68de514 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -15,9 +15,17 @@
struct stack_trace *trace);
extern void print_stack_trace(struct stack_trace *trace, int spaces);
+
+#ifdef CONFIG_X86
+extern void save_stack_trace_user(struct stack_trace *trace);
+#else
+# define save_stack_trace_user(trace) do { } while (0)
+#endif
+
#else
# define save_stack_trace(trace) do { } while (0)
# define save_stack_trace_tsk(tsk, trace) do { } while (0)
+# define save_stack_trace_user(trace) do { } while (0)
# define print_stack_trace(trace, spaces) do { } while (0)
#endif