[PATCH 2/4] tracing/histogram: Fix a few problems with stacktrace variable printing
From: Tom Zanussi
Date: Fri Feb 10 2023 - 16:33:26 EST
Currently, there are a few problems when printing hist triggers and
trace output when using stacktrace variables. This fixes the problems
seen below:
# echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger
# cat /sys/kernel/debug/tracing/events/synthetic/block_lat/trigger
hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
# echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
hist:keys=next_pid:vals=hitcount:ts=common_timestamp.usecs,st=stacktrace.stacktrace:sort=hitcount:size=2048:clock=global if prev_state == 2 [active]
and also in the trace output (should be stack.stacktrace):
{ delta: ~ 100-199, stacktrace __schedule+0xa19/0x1520
Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx>
---
kernel/trace/trace_events_hist.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 76bd105988c6..a58380702491 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1356,9 +1356,12 @@ static const char *hist_field_name(struct hist_field *field,
field_name = field->name;
} else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
field_name = "common_timestamp";
- else if (field->flags & HIST_FIELD_FL_STACKTRACE)
- field_name = "stacktrace";
- else if (field->flags & HIST_FIELD_FL_HITCOUNT)
+ else if (field->flags & HIST_FIELD_FL_STACKTRACE) {
+ if (field->field)
+ field_name = field->field->name;
+ else
+ field_name = "stacktrace";
+ } else if (field->flags & HIST_FIELD_FL_HITCOUNT)
field_name = "hitcount";
if (field_name == NULL)
@@ -5334,7 +5337,10 @@ static void hist_trigger_print_key(struct seq_file *m,
seq_printf(m, "%s: %-30s[%3llu]", field_name,
syscall_name, uval);
} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
- seq_puts(m, "stacktrace:\n");
+ if (key_field->field)
+ seq_printf(m, "%s.stacktrace", key_field->field->name);
+ else
+ seq_puts(m, "stacktrace:\n");
hist_trigger_stacktrace_print(m,
key + key_field->offset,
HIST_STACKTRACE_DEPTH);
@@ -5879,7 +5885,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
if (hist_field->flags) {
if (!(hist_field->flags & HIST_FIELD_FL_VAR_REF) &&
- !(hist_field->flags & HIST_FIELD_FL_EXPR)) {
+ !(hist_field->flags & HIST_FIELD_FL_EXPR) &&
+ !(hist_field->flags & HIST_FIELD_FL_STACKTRACE)) {
const char *flags = get_hist_field_flags(hist_field);
if (flags)
@@ -5912,9 +5919,12 @@ static int event_hist_trigger_print(struct seq_file *m,
if (i > hist_data->n_vals)
seq_puts(m, ",");
- if (field->flags & HIST_FIELD_FL_STACKTRACE)
- seq_puts(m, "stacktrace");
- else
+ if (field->flags & HIST_FIELD_FL_STACKTRACE) {
+ if (field->field)
+ seq_printf(m, "%s.stacktrace", field->field->name);
+ else
+ seq_puts(m, "stacktrace");
+ } else
hist_field_print(m, field);
}
--
2.34.1