On Mon, 6 Dec 2021 17:13:52 +0200
"Yordan Karadzhov (VMware)" <y.karadz@xxxxxxxxx> wrote:
> The new APIs can be useful in the case whene the user wants to
> check what exactly gets passed to the kernel as definition of
> a synth event.
Please list the APIs.
>
> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx>
> ---
> include/tracefs.h | 4 ++
> src/tracefs-hist.c | 102 +++++++++++++++++++++++++++++++++++++--------
> 2 files changed, 88 insertions(+), 18 deletions(-)
>
> diff --git a/include/tracefs.h b/include/tracefs.h
> index 804d738..9ad036c 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -250,6 +250,7 @@ enum tracefs_dynevent_type {
> TRACEFS_DYNEVENT_SYNTH = 1 << 5,
> TRACEFS_DYNEVENT_MAX = 1 << 6,
> };
> +
> int tracefs_dynevent_create(struct tracefs_dynevent *devent);
> int tracefs_dynevent_destroy(struct tracefs_dynevent *devent, bool force);
> int tracefs_dynevent_destroy_all(unsigned int types, bool force);
> @@ -553,6 +554,9 @@ int tracefs_synth_create(struct tracefs_synth *synth);
> int tracefs_synth_destroy(struct tracefs_synth *synth);
> void tracefs_synth_free(struct tracefs_synth *synth);
> int tracefs_synth_echo_cmd(struct trace_seq *seq, struct tracefs_synth *synth);
> +const char *tracefs_synth_show_event_row(struct tracefs_synth *synth);
> +const char *tracefs_synth_show_start_hist_row(struct tracefs_synth *synth);
> +const char *tracefs_synth_show_end_hist_row(struct tracefs_synth *synth);
>
> struct tracefs_synth *tracefs_sql(struct tep_handle *tep, const char *name,
> const char *sql_buffer, char **err);
> diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
> index 41c88d1..338249d 100644
> --- a/src/tracefs-hist.c
> +++ b/src/tracefs-hist.c
> @@ -717,6 +717,8 @@ struct tracefs_synth {
> struct action *actions;
> struct action **next_action;
> struct tracefs_dynevent *dyn_event;
> + char *start_hist;
> + char *end_hist;
> char *name;
> char **synthetic_fields;
> char **synthetic_args;
> @@ -771,6 +773,8 @@ void tracefs_synth_free(struct tracefs_synth *synth)
> return;
>
> free(synth->name);
> + free(synth->start_hist);
> + free(synth->end_hist);
> tracefs_list_free(synth->synthetic_fields);
> tracefs_list_free(synth->synthetic_args);
> tracefs_list_free(synth->start_keys);
> @@ -1067,6 +1071,9 @@ struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
> synth = NULL;
> }
>
> + synth->start_hist = NULL;
> + synth->end_hist = NULL;
> +
> return synth;
> }
>
> @@ -1836,6 +1843,72 @@ static char *create_end_hist(struct tracefs_synth *synth)
> return create_actions(end_hist, synth);
> }
>
> +/*
> + * tracefs_synth_echo_fmt - show the raw format of a synthetic event
> + * @seq: A trace_seq to store the format string
> + * @synth: The synthetic event to read format from
> + *
> + * This shows the raw format that describes the synthetic event, including
> + * the format of the dynamic event and the start / end histograms.
> + *
> + * Returns 0 on succes -1 on error.
> + */
> +int tracefs_synth_echo_fmt(struct trace_seq *seq,
> + struct tracefs_instance *instance,
> + struct tracefs_synth *synth)
> +{
> + if (!synth->dyn_event)
> + return -1;
> +
> + trace_seq_printf(seq, "%s\n", synth->dyn_event->format);
> + trace_seq_printf(seq, "%s\n", synth->start_hist);
> + trace_seq_printf(seq, "%s\n", synth->end_hist);
> +
> + return 0;
> +}
> +
> +/*
> + * tracefs_synth_show_event_row - show the dynamic event used by a synthetic
> + * event
> + * @synth: The synthetic event to read format from
> + *
> + * This shows the raw format of the dynamic event used by the synthetic event.
> + *
> + * Returns format string on succes or NULL on error.
Should probably state that the string returned belongs to the synth
descriptor.
> + */
> +const char *tracefs_synth_show_event_row(struct tracefs_synth *synth)
> +{
> + return synth->dyn_event ? synth->dyn_event->format : NULL;
> +}
> +
> +/*
> + * tracefs_synth_show_start_hist_row - show the start histogram used by a
> + * synthetic event
> + * @synth: The synthetic event to read format from
> + *
> + * This shows the raw format of the start histogram used by the synthetic event.
> + *
> + * Returns format string on succes or NULL on error.
Here too. And typo in all the comments. "success"
> + */
> +const char *tracefs_synth_show_start_hist_row(struct tracefs_synth *synth)
> +{
> + return synth->start_hist;
> +}
> +
> +/*
> + * tracefs_synth_show_end_hist_row - show the end histogram used by a
> + * synthetic event
> + * @synth: The synthetic event to read format from
> + *
> + * This shows the raw format of the end histogram used by the synthetic event.
> + *
> + * Returns format string on succes or NULL on error.
Same here.
> + */
> +const char *tracefs_synth_show_end_hist_row(struct tracefs_synth *synth)
> +{
> + return synth->end_hist;
> +}
> +
> static char *append_filter(char *hist, char *filter, unsigned int parens)
> {
> int i;
> @@ -1974,8 +2047,6 @@ tracefs_synth_get_start_hist(struct tracefs_synth *synth)
> */
> int tracefs_synth_create(struct tracefs_synth *synth)
> {
> - char *start_hist = NULL;
> - char *end_hist = NULL;
> int ret;
>
> if (!synth) {
> @@ -1996,40 +2067,35 @@ int tracefs_synth_create(struct tracefs_synth *synth)
> if (tracefs_dynevent_create(synth->dyn_event))
> return -1;
>
> - start_hist = create_hist(synth->start_keys, synth->start_vars);
> - start_hist = append_filter(start_hist, synth->start_filter,
> - synth->start_parens);
> - if (!start_hist)
> + synth->start_hist = create_hist(synth->start_keys, synth->start_vars);
> + synth->start_hist = append_filter(synth->start_hist, synth->start_filter,
> + synth->start_parens);
> + if (!synth->start_hist)
> goto remove_synthetic;
>
> - end_hist = create_end_hist(synth);
> - end_hist = append_filter(end_hist, synth->end_filter,
> - synth->end_parens);
> - if (!end_hist)
> + synth->end_hist = create_end_hist(synth);
> + synth->end_hist = append_filter(synth->end_hist, synth->end_filter,
> + synth->end_parens);
> + if (!synth->end_hist)
> goto remove_synthetic;
>
> ret = tracefs_event_file_append(synth->instance, synth->start_event->system,
> synth->start_event->name,
> - "trigger", start_hist);
> + "trigger", synth->start_hist);
> if (ret < 0)
> goto remove_synthetic;
>
> ret = tracefs_event_file_append(synth->instance, synth->end_event->system,
> synth->end_event->name,
> - "trigger", end_hist);
> + "trigger", synth->end_hist);
> if (ret < 0)
> goto remove_start_hist;
>
> - free(start_hist);
> - free(end_hist);
> -
> return 0;
>
> remove_start_hist:
> - remove_hist(synth->instance, synth->start_event, start_hist);
> + remove_hist(synth->instance, synth->start_event, synth->start_hist);
> remove_synthetic:
> - free(end_hist);
> - free(start_hist);
> tracefs_dynevent_destroy(synth->dyn_event, false);
I just realized that on error, we do not free the synthetic event
descriptor. So there is a memory leak.
Also, I'm thinking that the specific functions for destroying the synthetic
events and such, should live here, and trace-dynevents.c should call them.
Because all the management for synthetic events should live in this file
(or go to its own file).
-- Steve
> return -1;
> }
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