[PATCH] fgraph: Remove redundant ftrace_graph_notrace_addr() test

* [PATCH] fgraph: Remove redundant ftrace_graph_notrace_addr() test
@ 2019-07-30 14:08 Changbin Du
  2019-07-30 16:15 ` Steven Rostedt
  0 siblings, 1 reply; 4+ messages in thread
From: Changbin Du @ 2019-07-30 14:08 UTC (permalink / raw)
  To: Steven Rostedt; +Cc: Ingo Molnar, linux-kernel, Changbin Du

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 <changbin.du@gmail.com>
---
 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


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