Re: [PATCH] ftrace: trigger: Call traceoff trigger after event recorded

[Masami Hiramatsu <mhiramat@kernel.org>]

Ping?

On Fri,  9 Sep 2016 01:05:45 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Call traceoff trigger after the event is recorded.
> Since current traceoff trigger is called before recording
> the event, we can not know when the trace is off by what event.
> 
> Typical usecase of traceoff/traceon trigger is tracing
> function calls and trace events between a pair of events.
> For example, trace function calls between syscall entry/exit.
> In that case, it is useful if we can see the return code
> of the target syscall.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
>  kernel/trace/trace_events_trigger.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
> index a975571..6721a1e8 100644
> --- a/kernel/trace/trace_events_trigger.c
> +++ b/kernel/trace/trace_events_trigger.c
> @@ -1028,6 +1028,7 @@ static struct event_command trigger_traceon_cmd = {
>  static struct event_command trigger_traceoff_cmd = {
>  	.name			= "traceoff",
>  	.trigger_type		= ETT_TRACE_ONOFF,
> +	.flags			= EVENT_CMD_FL_POST_TRIGGER,
>  	.func			= event_trigger_callback,
>  	.reg			= register_trigger,
>  	.unreg			= unregister_trigger,
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>