perf tools: Flush remaining samples w/o deferred callchains

It's possible that some kernel samples don't have matching deferred
callchain records when the profiling session was ended before the
threads came back to userspace. Let's flush the samples before
finish the session.

Reviewed-by: Ian Rogers <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/util/session.c

···
 	union perf_event *event;
 };
 
+/*
+ * This is called when a deferred callchain record comes up.  Find all matching
+ * samples, merge the callchains and process them.
+ */
 static int evlist__deliver_deferred_callchain(struct evlist *evlist,
 					      const struct perf_tool *tool,
 					      union  perf_event *event,
···
 
 		if (orig_sample.deferred_callchain)
 			free(orig_sample.callchain);
+
+		list_del(&de->list);
+		free(de->event);
+		free(de);
+
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+/*
+ * This is called at the end of the data processing for the session.  Flush the
+ * remaining samples as there's no hope for matching deferred callchains.
+ */
+static int session__flush_deferred_samples(struct perf_session *session,
+					   const struct perf_tool *tool)
+{
+	struct evlist *evlist = session->evlist;
+	struct machine *machine = &session->machines.host;
+	struct deferred_event *de, *tmp;
+	struct evsel *evsel;
+	int ret = 0;
+
+	list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) {
+		struct perf_sample sample;
+
+		ret = evlist__parse_sample(evlist, de->event, &sample);
+		if (ret < 0) {
+			pr_err("failed to parse original sample\n");
+			break;
+		}
+
+		evsel = evlist__id2evsel(evlist, sample.id);
+		ret = evlist__deliver_sample(evlist, tool, de->event,
+					     &sample, evsel, machine);
 
 		list_del(&de->list);
 		free(de->event);
···
 	err = ordered_events__flush(oe, OE_FLUSH__FINAL);
 	if (err)
 		goto out_err;
+	err = session__flush_deferred_samples(session, tool);
+	if (err)
+		goto out_err;
 	err = auxtrace__flush_events(session, tool);
 	if (err)
 		goto out_err;
···
 	err = auxtrace__flush_events(session, tool);
 	if (err)
 		goto out_err;
+	err = session__flush_deferred_samples(session, tool);
+	if (err)
+		goto out_err;
 	err = perf_session__flush_thread_stacks(session);
 out_err:
 	ui_progress__finish();
···
 	}
 
 	ret = ordered_events__flush(&session->ordered_events, OE_FLUSH__FINAL);
+	if (ret)
+		goto out_err;
+
+	ret = session__flush_deferred_samples(session, tool);
 	if (ret)
 		goto out_err;