--- old/src/hotspot/share/gc/z/zPage.inline.hpp	2019-07-08 17:19:18.778725731 +0000
+++ new/src/hotspot/share/gc/z/zPage.inline.hpp	2019-07-08 17:19:18.506725449 +0000
@@ -146,7 +146,15 @@
 }
 
 inline bool ZPage::is_allocating() const {
-  return _seqnum == ZGlobalSeqNum;
+  return _seqnum >= ZGlobalSeqNum;
+}
+
+inline void ZPage::pin_allocating() {
+  _seqnum = (uint32_t)-1;
+}
+
+inline void ZPage::unpin_allocating() {
+  _seqnum = ZGlobalSeqNum;
 }
 
 inline bool ZPage::is_relocatable() const {