tracing: Deprecate tracing_enabled for tracing_on
tracing_enabled should not be used, it is heavy weight and does not
do much in helping lower the overhead.
tracing_on should be used instead. Warn users to use tracing_on
when tracing_enabled is used as it will soon be removed from the
tracing directory.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 65eddb7..67f1cc4 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -80,11 +80,11 @@
tracers listed here can be configured by
echoing their name into current_tracer.
- tracing_enabled:
+ tracing_on:
- This sets or displays whether the current_tracer
- is activated and tracing or not. Echo 0 into this
- file to disable the tracer or 1 to enable it.
+ This sets or displays whether writing to the trace
+ ring buffer is enabled. Echo 0 into this file to disable
+ the tracer or 1 to enable it.
trace:
@@ -497,10 +497,10 @@
# echo irqsoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: irqsoff
#
@@ -605,10 +605,10 @@
# echo preemptoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: preemptoff
#
@@ -753,10 +753,10 @@
# echo preemptirqsoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: preemptirqsoff
#
@@ -916,9 +916,9 @@
# echo wakeup > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# chrt -f 5 sleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: wakeup
#
@@ -1030,9 +1030,9 @@
# sysctl kernel.ftrace_enabled=1
# echo function > current_tracer
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: function
#
@@ -1070,7 +1070,7 @@
[...]
int main(int argc, char *argv[]) {
[...]
- trace_fd = open(tracing_file("tracing_enabled"), O_WRONLY);
+ trace_fd = open(tracing_file("tracing_on"), O_WRONLY);
[...]
if (condition_hit()) {
write(trace_fd, "0", 1);
@@ -1521,9 +1521,9 @@
# echo sys_nanosleep hrtimer_interrupt \
> set_ftrace_filter
# echo function > current_tracer
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: ftrace
#
@@ -1769,9 +1769,9 @@
# echo function > current_tracer
# cat trace_pipe > /tmp/trace.out &
[1] 4153
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: function
#
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dc53ecb..8dc8da6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2710,6 +2710,10 @@
mutex_lock(&trace_types_lock);
if (tracer_enabled ^ val) {
+
+ /* Only need to warn if this is used to change the state */
+ WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
+
if (val) {
tracer_enabled = 1;
if (current_trace->start)