diff options
| -rw-r--r-- | Documentation/trace/ftrace.txt | 38 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 4 |
2 files changed, 23 insertions, 19 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index 65eddb7cfa02..67f1cc473257 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -80,11 +80,11 @@ of ftrace. Here is a list of some of the key files: 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 @@ an example: # 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 @@ is much like the irqsoff tracer. # 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 @@ tracers. # 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 @@ Instead of performing an 'ls', we will run 'sleep 1' under # 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 @@ ftrace_enabled is set; otherwise this tracer is a nop. # 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 trace_fd; [...] 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 @@ If I am only interested in sys_nanosleep and hrtimer_interrupt: # 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 @@ different. The trace is live. # 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 dc53ecb80589..8dc8da6733f9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2710,6 +2710,10 @@ tracing_ctrl_write(struct file *filp, const char __user *ubuf, 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) |