From: Changbin Du changbin.du@gmail.com
commit 6c77221df96177da0520847ce91e33f539fb8b2d upstream.
We already have tested it before. The second one should be removed. With this change, the performance should have little improvement.
Link: http://lkml.kernel.org/r/20190730140850.7927-1-changbin.du@gmail.com
Cc: stable@vger.kernel.org Fixes: 9cd2992f2d6c ("fgraph: Have set_graph_notrace only affect function_graph tracer") Signed-off-by: Changbin Du changbin.du@gmail.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/trace/trace_functions_graph.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)
--- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -137,6 +137,13 @@ int trace_graph_entry(struct ftrace_grap 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); /* @@ -156,16 +163,6 @@ int trace_graph_entry(struct ftrace_grap 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. */