[44/54] tracing: Fix display of hist trigger expressions containing timestamps

Commit Message

[e-mail] Aug. 29, 2018, 12:17 p.m. UTC

When displaying hist triggers, variable references that have the
timestamp field flag set are erroneously displayed as common_timestamp
rather than the variable reference.  Additionally, timestamp
expressions are displayed in the same way.  Fix this by forcing the
timestamp flag handling to follow variable reference and expression
handling.

Before:

  # cat /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
  hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs:...

After:

  # cat /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
  hist:keys=next_pid:vals=hitcount:wakeup_lat=common_timestamp.usecs-$ts0.usecs:...

Link: http://lkml.kernel.org/r/927[e-mail]

Signed-off-by: Tom Zanussi <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>
(cherry picked from commit 0ae7961e75c3fe3383796323d5342cbda8f82536)
Signed-off-by: Hirotaka MOTAI <[e-mail]>
---
 kernel/trace/trace_events_hist.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

Patch

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index a02bc09d..4f4792f4 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1681,34 +1681,33 @@  static const char *hist_field_name(struct hist_field *field,
 	if (level > 1)
 		return field_name;
 
 	if (field->field)
 		field_name = field->field->name;
 	else if (field->flags & HIST_FIELD_FL_LOG2 ||
 		 field->flags & HIST_FIELD_FL_ALIAS)
 		field_name = hist_field_name(field->operands[0], ++level);
-	else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
-		field_name = "common_timestamp";
 	else if (field->flags & HIST_FIELD_FL_CPU)
 		field_name = "cpu";
 	else if (field->flags & HIST_FIELD_FL_EXPR ||
 		 field->flags & HIST_FIELD_FL_VAR_REF) {
 		if (field->system) {
 			static char full_name[MAX_FILTER_STR_VAL];
 
 			strcat(full_name, field->system);
 			strcat(full_name, ".");
 			strcat(full_name, field->event_name);
 			strcat(full_name, ".");
 			strcat(full_name, field->name);
 			field_name = full_name;
 		} else
 			field_name = field->name;
-	}
+	} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
+		field_name = "common_timestamp";
 
 	if (field_name == NULL)
 		field_name = "";
 
 	return field_name;
 }
 
 static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
@@ -4853,33 +4852,25 @@  const struct file_operations event_hist_fops = {
 
 static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
 {
 	const char *field_name = hist_field_name(hist_field, 0);
 
 	if (hist_field->var.name)
 		seq_printf(m, "%s=", hist_field->var.name);
 
-	if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
-		seq_puts(m, "common_timestamp");
-	else if (hist_field->flags & HIST_FIELD_FL_CPU)
+	if (hist_field->flags & HIST_FIELD_FL_CPU)
 		seq_puts(m, "cpu");
 	else if (field_name) {
 		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||
 		    hist_field->flags & HIST_FIELD_FL_ALIAS)
 			seq_putc(m, '$');
 		seq_printf(m, "%s", field_name);
-	}
-
-	if (hist_field->flags) {
-		const char *flags_str = get_hist_field_flags(hist_field);
-
-		if (flags_str)
-			seq_printf(m, ".%s", flags_str);
-	}
+	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
+		seq_puts(m, "common_timestamp");
 }
 
 static int event_hist_trigger_print(struct seq_file *m,
 				    struct event_trigger_ops *ops,
 				    struct event_trigger_data *data)
 {
 	struct hist_trigger_data *hist_data = data->private_data;
 	struct hist_field *field;