ring-buffer: Add recording of ring buffer recursion into recursed_functions

Add a new config RING_BUFFER_RECORD_RECURSION that will place functions that
recurse from the ring buffer into the ftrace recused_functions file.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 9b11c096d139..6aa36ec73ccb 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -752,6 +752,20 @@ config FTRACE_RECORD_RECURSION_SIZE
 	  This file can be reset, but the limit can not change in
 	  size at runtime.
 
+config RING_BUFFER_RECORD_RECURSION
+	bool "Record functions that recurse in the ring buffer"
+	depends on FTRACE_RECORD_RECURSION
+	# default y, because it is coupled with FTRACE_RECORD_RECURSION
+	default y
+	help
+	  The ring buffer has its own internal recursion. Although when
+	  recursion happens it wont cause harm because of the protection,
+	  but it does cause an unwanted overhead. Enabling this option will
+	  place where recursion was detected into the ftrace "recursed_functions"
+	  file.
+
+	  This will add more overhead to cases that have recursion.
+
 config GCOV_PROFILE_FTRACE
 	bool "Enable GCOV profiling on ftrace subsystem"
 	depends on GCOV_KERNEL