tracing: let user specify tracing_thresh after selecting function_graph
Currently, tracing_thresh works only if we specify it before selecting
function_graph tracer. If we do the opposite, tracing_thresh will change
it's value, but it will not be applied.
To fix it, we add update_thresh callback which is called whenever
tracing_thresh is updated and for function_graph tracer we register
handler which reinitializes tracer depending on tracing_thresh.
Link: http://lkml.kernel.org/p/20140718111727.GA3206@stfomichev-desktop.yandex.net
Signed-off-by: Stanislav Fomichev <stfomichev@yandex-team.ru>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 2c944e6..74d9882 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -475,6 +475,12 @@
unregister_ftrace_graph();
}
+int graph_trace_update_thresh(struct trace_array *tr)
+{
+ graph_trace_reset(tr);
+ return graph_trace_init(tr);
+}
+
static int max_bytes_for_cpu;
static enum print_line_t
@@ -1525,6 +1531,7 @@
static struct tracer graph_trace __tracer_data = {
.name = "function_graph",
+ .update_thresh = graph_trace_update_thresh,
.open = graph_trace_open,
.pipe_open = graph_trace_open,
.close = graph_trace_close,