Re: [RFC PATCH v3 2/4] trace: Add an entry for printing trace log to STM

[Steven Rostedt <rostedt@goodmis.org>]

On Tue,  7 Jul 2015 18:10:41 +0800
Chunyan Zhang <zhang.chunyan@linaro.org> wrote:

> output_stm is a link which is used to connect trace event
> logging with STMs, will be used in the upcoming patches.
> 
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> ---
>  include/linux/trace_events.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
> index 1063c85..28dcdff 100644
> --- a/include/linux/trace_events.h
> +++ b/include/linux/trace_events.h
> @@ -14,6 +14,7 @@ struct trace_buffer;
>  struct tracer;
>  struct dentry;
>  struct bpf_prog;
> +struct trace_buffer_stm;
>  
>  struct trace_print_flags {
>  	unsigned long		mask;
> @@ -293,6 +294,9 @@ struct trace_event_call {
>  	 */
>  	int			flags; /* static flags of different events */
>  
> +	void (*output_stm)(struct trace_seq *tmp_seq, void *entry,
> +			   struct trace_buffer_stm *tb);
> +

Shouldn't the above also have a #ifdef CONFIG_STM_TRACE_EVENT
encompassing it? Otherwise we are adding 8 bytes to every trace event.

-- Steve

>  #ifdef CONFIG_PERF_EVENTS
>  	int				perf_refcount;
>  	struct hlist_head __percpu	*perf_events;
> @@ -412,6 +416,10 @@ enum event_trigger_type {
>  	ETT_EVENT_ENABLE	= (1 << 3),
>  };
>  
> +#ifdef CONFIG_STM_TRACE_EVENT
> +extern void stm_trace_event_write(const char *buf, unsigned len);
> +#endif
> +
>  extern int filter_match_preds(struct event_filter *filter, void *rec);
>  
>  extern int filter_check_discard(struct trace_event_file *file, void *rec,