[patch V2 20/29] tracing: Simplify stacktrace retrieval in histograms

Thomas Gleixner
2019-04-18T09:33:44Z

The indirection through struct stack_trace is not necessary at all. Use the
storage array based interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_events_hist.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5186,7 +5186,6 @@ static void event_hist_trigger(struct ev
u64 var_ref_vals[TRACING_MAP_VARS_MAX];
char compound_key[HIST_KEY_SIZE_MAX];
struct tracing_map_elt *elt = NULL;
- struct stack_trace stacktrace;
struct hist_field *key_field;
u64 field_contents;
void *key = NULL;
@@ -5198,14 +5197,9 @@ static void event_hist_trigger(struct ev
key_field = hist_data->fields[i];

if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
- stacktrace.max_entries = HIST_STACKTRACE_DEPTH;
- stacktrace.entries = entries;
- stacktrace.nr_entries = 0;
- stacktrace.skip = HIST_STACKTRACE_SKIP;
-
- memset(stacktrace.entries, 0, HIST_STACKTRACE_SIZE);
- save_stack_trace(&stacktrace);
-
+ memset(entries, 0, HIST_STACKTRACE_SIZE);
+ stack_trace_save(entries, HIST_STACKTRACE_DEPTH,
+ HIST_STACKTRACE_SKIP);
key = entries;
} else {
field_contents = key_field->fn(key_field, elt, rbe, rec);