diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index 7f618f4..225e963 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -305,6 +305,7 @@
 
 static int process_sample_event(union perf_event *event,
 				struct perf_sample *sample,
+				struct perf_evsel *evsel __used,
 				struct perf_session *session)
 {
 	struct thread *thread = perf_session__findnew(session, event->ip.pid);