Re: [PATCH v10 18/29] perf timechart: Don't pass evsel with sample

[Namhyung Kim]

On Sat, Apr 11, 2026 at 07:08:21PM -0700, Ian Rogers wrote:
> The sample contains the evsel and so it is unnecessary to pass the
> evsel as well. Add missing backtrace argument to tracepoint_handler
> functions and mark them unused. Fix missing free from cat_backtrace,
> which requires copies of the backtrace being made in functions that
> save it.

I've splitted the backtrace handling part into a new commit.

Thanks,
Namhyung

> 
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
>  tools/perf/builtin-timechart.c | 81 ++++++++++++++++------------------
>  1 file changed, 39 insertions(+), 42 deletions(-)
> 
> diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
> index 034e0ba3f9cb..64f69bd67c6b 100644
> --- a/tools/perf/builtin-timechart.c
> +++ b/tools/perf/builtin-timechart.c
> @@ -299,7 +299,7 @@ static void pid_put_sample(struct timechart *tchart, int pid, int type,
>  	sample->type = type;
>  	sample->next = c->samples;
>  	sample->cpu = cpu;
> -	sample->backtrace = backtrace;
> +	sample->backtrace = backtrace ? strdup(backtrace) : NULL;
>  	c->samples = sample;
>  
>  	if (sample->type == TYPE_RUNNING && end > start && start > 0) {
> @@ -433,7 +433,7 @@ static void sched_wakeup(struct timechart *tchart, int cpu, u64 timestamp,
>  
>  	we->time = timestamp;
>  	we->waker = waker;
> -	we->backtrace = backtrace;
> +	we->backtrace = backtrace ? strdup(backtrace) : NULL;
>  
>  	if ((flags & TRACE_FLAG_HARDIRQ) || (flags & TRACE_FLAG_SOFTIRQ))
>  		we->waker = -1;
> @@ -489,9 +489,9 @@ static void sched_switch(struct timechart *tchart, int cpu, u64 timestamp,
>  	}
>  }
>  
> -static const char *cat_backtrace(union perf_event *event,
> -				 struct perf_sample *sample,
> -				 struct machine *machine)
> +static char *cat_backtrace(union perf_event *event,
> +			   struct perf_sample *sample,
> +			   struct machine *machine)
>  {
>  	struct addr_location al;
>  	unsigned int i;
> @@ -544,8 +544,10 @@ static const char *cat_backtrace(union perf_event *event,
>  				 * It seems the callchain is corrupted.
>  				 * Discard all.
>  				 */
> -				zfree(&p);
> -				goto exit;
> +				addr_location__exit(&al);
> +				fclose(f);
> +				free(p);
> +				return NULL;
>  			}
>  			continue;
>  		}
> @@ -567,7 +569,6 @@ static const char *cat_backtrace(union perf_event *event,
>  }
>  
>  typedef int (*tracepoint_handler)(struct timechart *tchart,
> -				  struct evsel *evsel,
>  				  struct perf_sample *sample,
>  				  const char *backtrace);
>  
> @@ -578,6 +579,7 @@ static int process_sample_event(const struct perf_tool *tool,
>  {
>  	struct timechart *tchart = container_of(tool, struct timechart, tool);
>  	struct evsel *evsel = sample->evsel;
> +	int ret = 0;
>  
>  	if (evsel->core.attr.sample_type & PERF_SAMPLE_TIME) {
>  		if (!tchart->first_time || tchart->first_time > sample->time)
> @@ -588,16 +590,17 @@ static int process_sample_event(const struct perf_tool *tool,
>  
>  	if (evsel->handler != NULL) {
>  		tracepoint_handler f = evsel->handler;
> -		return f(tchart, evsel, sample,
> -			 cat_backtrace(event, sample, machine));
> +		char *backtrace = cat_backtrace(event, sample, machine);
> +
> +		ret = f(tchart, sample, backtrace);
> +		free(backtrace);
>  	}
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static int
>  process_sample_cpu_idle(struct timechart *tchart __maybe_unused,
> -			struct evsel *evsel __maybe_unused,
>  			struct perf_sample *sample,
>  			const char *backtrace __maybe_unused)
>  {
> @@ -613,7 +616,6 @@ process_sample_cpu_idle(struct timechart *tchart __maybe_unused,
>  
>  static int
>  process_sample_cpu_frequency(struct timechart *tchart,
> -			     struct evsel *evsel __maybe_unused,
>  			     struct perf_sample *sample,
>  			     const char *backtrace __maybe_unused)
>  {
> @@ -626,7 +628,6 @@ process_sample_cpu_frequency(struct timechart *tchart,
>  
>  static int
>  process_sample_sched_wakeup(struct timechart *tchart,
> -			    struct evsel *evsel __maybe_unused,
>  			    struct perf_sample *sample,
>  			    const char *backtrace)
>  {
> @@ -640,7 +641,6 @@ process_sample_sched_wakeup(struct timechart *tchart,
>  
>  static int
>  process_sample_sched_switch(struct timechart *tchart,
> -			    struct evsel *evsel __maybe_unused,
>  			    struct perf_sample *sample,
>  			    const char *backtrace)
>  {
> @@ -656,7 +656,6 @@ process_sample_sched_switch(struct timechart *tchart,
>  #ifdef SUPPORT_OLD_POWER_EVENTS
>  static int
>  process_sample_power_start(struct timechart *tchart __maybe_unused,
> -			   struct evsel *evsel __maybe_unused,
>  			   struct perf_sample *sample,
>  			   const char *backtrace __maybe_unused)
>  {
> @@ -669,7 +668,6 @@ process_sample_power_start(struct timechart *tchart __maybe_unused,
>  
>  static int
>  process_sample_power_end(struct timechart *tchart,
> -			 struct evsel *evsel __maybe_unused,
>  			 struct perf_sample *sample,
>  			 const char *backtrace __maybe_unused)
>  {
> @@ -679,7 +677,6 @@ process_sample_power_end(struct timechart *tchart,
>  
>  static int
>  process_sample_power_frequency(struct timechart *tchart,
> -			       struct evsel *evsel __maybe_unused,
>  			       struct perf_sample *sample,
>  			       const char *backtrace __maybe_unused)
>  {
> @@ -849,8 +846,8 @@ static int pid_end_io_sample(struct timechart *tchart, int pid, int type,
>  
>  static int
>  process_enter_read(struct timechart *tchart,
> -		   struct evsel *evsel __maybe_unused,
> -		   struct perf_sample *sample)
> +		   struct perf_sample *sample,
> +		   const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_READ,
> @@ -859,8 +856,8 @@ process_enter_read(struct timechart *tchart,
>  
>  static int
>  process_exit_read(struct timechart *tchart,
> -		  struct evsel *evsel __maybe_unused,
> -		  struct perf_sample *sample)
> +		  struct perf_sample *sample,
> +		  const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_READ,
> @@ -869,8 +866,8 @@ process_exit_read(struct timechart *tchart,
>  
>  static int
>  process_enter_write(struct timechart *tchart,
> -		    struct evsel *evsel __maybe_unused,
> -		    struct perf_sample *sample)
> +		    struct perf_sample *sample,
> +		    const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_WRITE,
> @@ -879,8 +876,8 @@ process_enter_write(struct timechart *tchart,
>  
>  static int
>  process_exit_write(struct timechart *tchart,
> -		   struct evsel *evsel __maybe_unused,
> -		   struct perf_sample *sample)
> +		   struct perf_sample *sample,
> +		   const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_WRITE,
> @@ -889,8 +886,8 @@ process_exit_write(struct timechart *tchart,
>  
>  static int
>  process_enter_sync(struct timechart *tchart,
> -		   struct evsel *evsel __maybe_unused,
> -		   struct perf_sample *sample)
> +		   struct perf_sample *sample,
> +		   const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_SYNC,
> @@ -899,8 +896,8 @@ process_enter_sync(struct timechart *tchart,
>  
>  static int
>  process_exit_sync(struct timechart *tchart,
> -		  struct evsel *evsel __maybe_unused,
> -		  struct perf_sample *sample)
> +		  struct perf_sample *sample,
> +		  const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_SYNC,
> @@ -909,8 +906,8 @@ process_exit_sync(struct timechart *tchart,
>  
>  static int
>  process_enter_tx(struct timechart *tchart,
> -		 struct evsel *evsel __maybe_unused,
> -		 struct perf_sample *sample)
> +		 struct perf_sample *sample,
> +		 const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_TX,
> @@ -919,8 +916,8 @@ process_enter_tx(struct timechart *tchart,
>  
>  static int
>  process_exit_tx(struct timechart *tchart,
> -		struct evsel *evsel __maybe_unused,
> -		struct perf_sample *sample)
> +		struct perf_sample *sample,
> +		const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_TX,
> @@ -929,8 +926,8 @@ process_exit_tx(struct timechart *tchart,
>  
>  static int
>  process_enter_rx(struct timechart *tchart,
> -		 struct evsel *evsel __maybe_unused,
> -		 struct perf_sample *sample)
> +		 struct perf_sample *sample,
> +		 const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_RX,
> @@ -939,8 +936,8 @@ process_enter_rx(struct timechart *tchart,
>  
>  static int
>  process_exit_rx(struct timechart *tchart,
> -		struct evsel *evsel __maybe_unused,
> -		struct perf_sample *sample)
> +		struct perf_sample *sample,
> +		const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_RX,
> @@ -949,8 +946,8 @@ process_exit_rx(struct timechart *tchart,
>  
>  static int
>  process_enter_poll(struct timechart *tchart,
> -		   struct evsel *evsel __maybe_unused,
> -		   struct perf_sample *sample)
> +		   struct perf_sample *sample,
> +		   const char *backtrace __maybe_unused)
>  {
>  	long fd = perf_sample__intval(sample, "fd");
>  	return pid_begin_io_sample(tchart, sample->tid, IOTYPE_POLL,
> @@ -959,8 +956,8 @@ process_enter_poll(struct timechart *tchart,
>  
>  static int
>  process_exit_poll(struct timechart *tchart,
> -		  struct evsel *evsel __maybe_unused,
> -		  struct perf_sample *sample)
> +		  struct perf_sample *sample,
> +		  const char *backtrace __maybe_unused)
>  {
>  	long ret = perf_sample__intval(sample, "ret");
>  	return pid_end_io_sample(tchart, sample->tid, IOTYPE_POLL,
> -- 
> 2.53.0.1213.gd9a14994de-goog
>