--- old/src/hotspot/share/gc/z/zHeap.cpp	2019-05-02 09:57:45.274909157 +0200
+++ new/src/hotspot/share/gc/z/zHeap.cpp	2019-05-02 09:57:45.051901792 +0200
@@ -45,6 +45,7 @@
 #include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/oop.inline.hpp"
+#include "runtime/arguments.hpp"
 #include "runtime/safepoint.hpp"
 #include "runtime/thread.hpp"
 #include "utilities/align.hpp"
@@ -62,7 +63,7 @@
 ZHeap::ZHeap() :
     _workers(),
     _object_allocator(_workers.nworkers()),
-    _page_allocator(heap_min_size(), heap_max_size(), heap_max_reserve_size()),
+    _page_allocator(heap_min_size(), heap_initial_size(), heap_max_size(), heap_max_reserve_size()),
     _page_table(),
     _forwarding_table(),
     _mark(&_workers, &_page_table),
@@ -81,8 +82,13 @@
 }
 
 size_t ZHeap::heap_min_size() const {
-  const size_t aligned_min_size = align_up(InitialHeapSize, ZGranuleSize);
-  return MIN2(aligned_min_size, heap_max_size());
+  const size_t aligned_min_size = align_up(Arguments::min_heap_size(), ZGranuleSize);
+  return MAX2(MIN2(aligned_min_size, heap_max_size()), heap_max_reserve_size());
+}
+
+size_t ZHeap::heap_initial_size() const {
+  const size_t aligned_initial_size = align_up(InitialHeapSize, ZGranuleSize);
+  return MAX2(MIN2(aligned_initial_size, heap_max_size()), heap_min_size());
 }
 
 size_t ZHeap::heap_max_size() const {
@@ -102,7 +108,7 @@
 }
 
 size_t ZHeap::min_capacity() const {
-  return heap_min_size();
+  return _page_allocator.min_capacity();
 }
 
 size_t ZHeap::max_capacity() const {
@@ -250,6 +256,10 @@
   _page_allocator.free_page(page, reclaimed);
 }
 
+uint64_t ZHeap::uncommit(uint64_t delay) {
+  return _page_allocator.uncommit(delay);
+}
+
 void ZHeap::before_flip() {
   if (ZVerifyViews) {
     // Unmap all pages