perf sched: No need to keep the session around

We were keeping the session around just because we kept pointers to
struct thread instances, but now we reference count them, so no need
for deferring the perf_session__delete call to after we traverse the
work_list entries.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-9agtck6jdr3rebdp39z1lo0e@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-sched.c

@@ -1439,8 +1439,7 @@ static int perf_sched__process_tracepoint_sample(struct perf_tool *tool __maybe_
 	return err;
 }
 
-static int perf_sched__read_events(struct perf_sched *sched,
-				   struct perf_session **psession)
+static int perf_sched__read_events(struct perf_sched *sched)
 {
 	const struct perf_evsel_str_handler handlers[] = {
 		{ "sched:sched_switch",	      process_sched_switch_event, },
@@ -1454,6 +1453,7 @@ static int perf_sched__read_events(struct perf_sched *sched,
 		.path = input_name,
 		.mode = PERF_DATA_MODE_READ,
 	};
+	int rc = -1;
 
 	session = perf_session__new(&file, false, &sched->tool);
 	if (session == NULL) {
@@ -1478,16 +1478,10 @@ static int perf_sched__read_events(struct perf_sched *sched,
 		sched->nr_lost_chunks = session->evlist->stats.nr_events[PERF_RECORD_LOST];
 	}
 
-	if (psession)
-		*psession = session;
-	else
-		perf_session__delete(session);
-
-	return 0;
-
+	rc = 0;
 out_delete:
 	perf_session__delete(session);
-	return -1;
+	return rc;
 }
 
 static void print_bad_events(struct perf_sched *sched)
@@ -1515,12 +1509,10 @@ static void print_bad_events(struct perf_sched *sched)
 static int perf_sched__lat(struct perf_sched *sched)
 {
 	struct rb_node *next;
-	struct perf_session *session;
 
 	setup_pager();
 
-	/* save session -- references to threads are held in work_list */
-	if (perf_sched__read_events(sched, &session))
+	if (perf_sched__read_events(sched))
 		return -1;
 
 	perf_sched__sort_lat(sched);
@@ -1537,6 +1529,7 @@ static int perf_sched__lat(struct perf_sched *sched)
 		work_list = rb_entry(next, struct work_atoms, node);
 		output_lat_thread(sched, work_list);
 		next = rb_next(next);
+		thread__zput(work_list->thread);
 	}
 
 	printf(" -----------------------------------------------------------------------------------------------------------------\n");
@@ -1548,7 +1541,6 @@ static int perf_sched__lat(struct perf_sched *sched)
 	print_bad_events(sched);
 	printf("\n");
 
-	perf_session__delete(session);
 	return 0;
 }
 
@@ -1557,7 +1549,7 @@ static int perf_sched__map(struct perf_sched *sched)
 	sched->max_cpu = sysconf(_SC_NPROCESSORS_CONF);
 
 	setup_pager();
-	if (perf_sched__read_events(sched, NULL))
+	if (perf_sched__read_events(sched))
 		return -1;
 	print_bad_events(sched);
 	return 0;
@@ -1572,7 +1564,7 @@ static int perf_sched__replay(struct perf_sched *sched)
 
 	test_calibrations(sched);
 
-	if (perf_sched__read_events(sched, NULL))
+	if (perf_sched__read_events(sched))
 		return -1;
 
 	printf("nr_run_events:        %ld\n", sched->nr_run_events);