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Diffstat (limited to 'kernel/trace/trace_sched_wakeup.c')
-rw-r--r--kernel/trace/trace_sched_wakeup.c63
1 files changed, 53 insertions, 10 deletions
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index c16f8cd63c3c..fee77e15d815 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -37,6 +37,7 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
static void wakeup_graph_return(struct ftrace_graph_ret *trace);
static int save_flags;
+static bool function_enabled;
#define TRACE_DISPLAY_GRAPH 1
@@ -134,15 +135,60 @@ static struct ftrace_ops trace_ops __read_mostly =
};
#endif /* CONFIG_FUNCTION_TRACER */
-static int start_func_tracer(int graph)
+static int register_wakeup_function(int graph, int set)
{
int ret;
- if (!graph)
- ret = register_ftrace_function(&trace_ops);
- else
+ /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
+ if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION)))
+ return 0;
+
+ if (graph)
ret = register_ftrace_graph(&wakeup_graph_return,
&wakeup_graph_entry);
+ else
+ ret = register_ftrace_function(&trace_ops);
+
+ if (!ret)
+ function_enabled = true;
+
+ return ret;
+}
+
+static void unregister_wakeup_function(int graph)
+{
+ if (!function_enabled)
+ return;
+
+ if (graph)
+ unregister_ftrace_graph();
+ else
+ unregister_ftrace_function(&trace_ops);
+
+ function_enabled = false;
+}
+
+static void wakeup_function_set(int set)
+{
+ if (set)
+ register_wakeup_function(is_graph(), 1);
+ else
+ unregister_wakeup_function(is_graph());
+}
+
+static int wakeup_flag_changed(struct tracer *tracer, u32 mask, int set)
+{
+ if (mask & TRACE_ITER_FUNCTION)
+ wakeup_function_set(set);
+
+ return trace_keep_overwrite(tracer, mask, set);
+}
+
+static int start_func_tracer(int graph)
+{
+ int ret;
+
+ ret = register_wakeup_function(graph, 0);
if (!ret && tracing_is_enabled())
tracer_enabled = 1;
@@ -156,10 +202,7 @@ static void stop_func_tracer(int graph)
{
tracer_enabled = 0;
- if (!graph)
- unregister_ftrace_function(&trace_ops);
- else
- unregister_ftrace_graph();
+ unregister_wakeup_function(graph);
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -600,7 +643,7 @@ static struct tracer wakeup_tracer __read_mostly =
.print_line = wakeup_print_line,
.flags = &tracer_flags,
.set_flag = wakeup_set_flag,
- .flag_changed = trace_keep_overwrite,
+ .flag_changed = wakeup_flag_changed,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_wakeup,
#endif
@@ -622,7 +665,7 @@ static struct tracer wakeup_rt_tracer __read_mostly =
.print_line = wakeup_print_line,
.flags = &tracer_flags,
.set_flag = wakeup_set_flag,
- .flag_changed = trace_keep_overwrite,
+ .flag_changed = wakeup_flag_changed,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_wakeup,
#endif
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