1 files changed, 17 insertions, 0 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 6430016b98e8..cad9db1dee02 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -88,3 +88,20 @@ config CONTEXT_SWITCH_TRACER
           This tracer gets called from the context switch and records
           all switching of tasks.
 
+config DYNAMIC_FTRACE
+        bool "enable/disable ftrace tracepoints dynamically"
+        depends on FTRACE
+        default y
+        help
+         This option will modify all the calls to ftrace dynamically
+         (will patch them out of the binary image and replaces them
+         with a No-Op instruction) as they are called. A table is
+         created to dynamically enable them again.
+
+         This way a CONFIG_FTRACE kernel is slightly larger, but otherwise
+         has native performance as long as no tracing is active.
+
+         The changes to the code are done by a kernel thread that
+         wakes up once a second and checks to see if any ftrace calls
+         were made. If so, it runs stop_machine (stops all CPUS)
+         and modifies the code to jump over the call to ftrace.