--- a/src/hotspot/share/gc/z/zHeap.cpp	Mon Mar 18 11:50:39 2019 +0100
+++ b/src/hotspot/share/gc/z/zHeap.cpp	Mon Mar 18 11:50:40 2019 +0100
@@ -404,17 +404,6 @@
   _reference_processor.enqueue_references();
 }
 
-void ZHeap::destroy_detached_pages() {
-  ZList<ZPage> list;
-
-  _page_allocator.flush_detached_pages(&list);
-
-  for (ZPage* page = list.remove_first(); page != NULL; page = list.remove_first()) {
-    // Delete the page
-    _page_allocator.destroy_page(page);
-  }
-}
-
 void ZHeap::select_relocation_set() {
   // Register relocatable pages with selector
   ZRelocationSetSelector selector;
@@ -464,6 +453,10 @@
   _relocation_set.reset();
 }
 
+void ZHeap::destroy_detached_pages() {
+  _page_allocator.destroy_detached_pages();
+}
+
 void ZHeap::relocate_start() {
   assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint");
 

--- a/src/hotspot/share/gc/z/zPageAllocator.cpp	Mon Mar 18 11:50:39 2019 +0100
+++ b/src/hotspot/share/gc/z/zPageAllocator.cpp	Mon Mar 18 11:50:40 2019 +0100
@@ -250,10 +250,19 @@
   _detached.insert_last(page);
 }
 
-void ZPageAllocator::destroy_page(ZPage* page) {
-  assert(page->is_detached(), "Invalid page state");
+void ZPageAllocator::destroy_detached_pages() {
+  ZList<ZPage> list;
 
-  delete page;
+  // Get and reset list of detached pages
+  {
+    ZLocker<ZLock> locker(&_lock);
+    list.transfer(&_detached);
+  }
+
+  // Destroy pages
+  for (ZPage* page = list.remove_first(); page != NULL; page = list.remove_first()) {
+    delete page;
+  }
 }
 
 void ZPageAllocator::map_page(ZPage* page) {
@@ -271,11 +280,6 @@
   pmem.clear();
 }
 
-void ZPageAllocator::flush_detached_pages(ZList<ZPage>* list) {
-  ZLocker<ZLock> locker(&_lock);
-  list->transfer(&_detached);
-}
-
 void ZPageAllocator::flush_cache(size_t size) {
   ZList<ZPage> list;
 

--- a/src/hotspot/share/gc/z/zPageAllocator.hpp	Mon Mar 18 11:50:39 2019 +0100
+++ b/src/hotspot/share/gc/z/zPageAllocator.hpp	Mon Mar 18 11:50:40 2019 +0100
@@ -97,13 +97,11 @@
 
   ZPage* alloc_page(uint8_t type, size_t size, ZAllocationFlags flags);
   void free_page(ZPage* page, bool reclaimed);
-  void destroy_page(ZPage* page);
+  void destroy_detached_pages();
 
   void map_page(ZPage* page);
   void unmap_all_pages();
 
-  void flush_detached_pages(ZList<ZPage>* list);
-
   bool is_alloc_stalled() const;
   void check_out_of_memory();
 };