We already have tested it before. The second one should be removed.
With this change, the performance should have little improvement.
Fixes: 9cd2992f2d6c ("fgraph: Have set_graph_notrace only affect function_graph
tracer")
Signed-off-by: Changbin Du <[email protected]>
---
kernel/trace/trace_functions_graph.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace_functions_graph.c
b/kernel/trace/trace_functions_graph.c
index 69ebf3c2f1b5..78af97163147 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -137,6 +137,13 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
return 0;
+ /*
+ * Do not trace a function if it's filtered by set_graph_notrace.
+ * Make the index of ret stack negative to indicate that it should
+ * ignore further functions. But it needs its own ret stack entry
+ * to recover the original index in order to continue tracing after
+ * returning from the function.
+ */
if (ftrace_graph_notrace_addr(trace->func)) {
trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
/*
@@ -155,16 +162,6 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
if (ftrace_graph_ignore_irqs())
return 0;
- /*
- * Do not trace a function if it's filtered by set_graph_notrace.
- * Make the index of ret stack negative to indicate that it should
- * ignore further functions. But it needs its own ret stack entry
- * to recover the original index in order to continue tracing after
- * returning from the function.
- */
- if (ftrace_graph_notrace_addr(trace->func))
- return 1;
-
/*
* Stop here if tracing_threshold is set. We only write function return
* events to the ring buffer.
--
2.20.1
