diff -r 76751d3faf7b -r 39ba09047e19 src/hotspot/share/gc/z/zCollectedHeap.cpp
--- a/src/hotspot/share/gc/z/zCollectedHeap.cpp	Tue May 14 09:12:06 2019 +0200
+++ b/src/hotspot/share/gc/z/zCollectedHeap.cpp	Tue May 14 09:55:02 2019 +0200
@@ -48,6 +48,7 @@
     _heap(),
     _director(new ZDirector()),
     _driver(new ZDriver()),
+    _uncommitter(new ZUncommitter()),
     _stat(new ZStat()),
     _runtime_workers() {}
 
@@ -77,6 +78,7 @@
 void ZCollectedHeap::stop() {
   _director->stop();
   _driver->stop();
+  _uncommitter->stop();
   _stat->stop();
 }
 
@@ -272,6 +274,7 @@
 void ZCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
   tc->do_thread(_director);
   tc->do_thread(_driver);
+  tc->do_thread(_uncommitter);
   tc->do_thread(_stat);
   _heap.worker_threads_do(tc);
   _runtime_workers.threads_do(tc);
@@ -331,6 +334,8 @@
   st->cr();
   _driver->print_on(st);
   st->cr();
+  _uncommitter->print_on(st);
+  st->cr();
   _stat->print_on(st);
   st->cr();
   _heap.print_worker_threads_on(st);