--- old/src/hotspot/share/gc/z/zRootsIterator.cpp	2020-06-24 11:28:31.073112762 +0200
+++ new/src/hotspot/share/gc/z/zRootsIterator.cpp	2020-06-24 11:28:30.905109461 +0200
@@ -30,7 +30,7 @@
 #include "gc/shared/barrierSetNMethod.hpp"
 #include "gc/shared/oopStorageSet.hpp"
 #include "gc/shared/oopStorageParState.inline.hpp"
-#include "gc/shared/oopStorageSet.hpp"
+#include "gc/shared/oopStorageSetParState.inline.hpp"
 #include "gc/shared/suspendibleThreadSet.hpp"
 #include "gc/z/zBarrierSetNMethod.hpp"
 #include "gc/z/zGlobals.hpp"
@@ -70,8 +70,7 @@
 static const ZStatSubPhase ZSubPhaseConcurrentRootsSetup("Concurrent Roots Setup");
 static const ZStatSubPhase ZSubPhaseConcurrentRoots("Concurrent Roots");
 static const ZStatSubPhase ZSubPhaseConcurrentRootsTeardown("Concurrent Roots Teardown");
-static const ZStatSubPhase ZSubPhaseConcurrentRootsJNIHandles("Concurrent Roots JNIHandles");
-static const ZStatSubPhase ZSubPhaseConcurrentRootsVMHandles("Concurrent Roots VMHandles");
+static const ZStatSubPhase ZSubPhaseConcurrentRootsOopStorageSet("Concurrent Roots OopStorageSet");
 static const ZStatSubPhase ZSubPhaseConcurrentRootsClassLoaderDataGraph("Concurrent Roots ClassLoaderDataGraph");
 
 static const ZStatSubPhase ZSubPhasePauseWeakRootsSetup("Pause Weak Roots Setup");
@@ -286,11 +285,9 @@
 }
 
 ZConcurrentRootsIterator::ZConcurrentRootsIterator(int cld_claim) :
-    _jni_handles_iter(OopStorageSet::jni_global()),
-    _vm_handles_iter(OopStorageSet::vm_global()),
+    _oop_storage_set_iter(),
     _cld_claim(cld_claim),
-    _jni_handles(this),
-    _vm_handles(this),
+    _oop_storage_set(this),
     _class_loader_data_graph(this) {
   ZStatTimer timer(ZSubPhaseConcurrentRootsSetup);
   ClassLoaderDataGraph::clear_claimed_marks(cld_claim);
@@ -300,14 +297,9 @@
   ZStatTimer timer(ZSubPhaseConcurrentRootsTeardown);
 }
 
-void ZConcurrentRootsIterator::do_jni_handles(ZRootsIteratorClosure* cl) {
-  ZStatTimer timer(ZSubPhaseConcurrentRootsJNIHandles);
-  _jni_handles_iter.oops_do(cl);
-}
-
-void ZConcurrentRootsIterator::do_vm_handles(ZRootsIteratorClosure* cl) {
-  ZStatTimer timer(ZSubPhaseConcurrentRootsVMHandles);
-  _vm_handles_iter.oops_do(cl);
+void ZConcurrentRootsIterator::do_oop_storage_set(ZRootsIteratorClosure* cl) {
+  ZStatTimer timer(ZSubPhaseConcurrentRootsOopStorageSet);
+  _oop_storage_set_iter.oops_do(cl);
 }
 
 void ZConcurrentRootsIterator::do_class_loader_data_graph(ZRootsIteratorClosure* cl) {
@@ -318,8 +310,7 @@
 
 void ZConcurrentRootsIterator::oops_do(ZRootsIteratorClosure* cl) {
   ZStatTimer timer(ZSubPhaseConcurrentRoots);
-  _jni_handles.oops_do(cl);
-  _vm_handles.oops_do(cl),
+  _oop_storage_set.oops_do(cl);
   _class_loader_data_graph.oops_do(cl);
 }
 
--- old/src/hotspot/share/gc/z/zRootsIterator.hpp	2020-06-24 11:28:31.385118894 +0200
+++ new/src/hotspot/share/gc/z/zRootsIterator.hpp	2020-06-24 11:28:31.229115828 +0200
@@ -25,6 +25,7 @@
 #define SHARE_GC_Z_ZROOTSITERATOR_HPP
 
 #include "gc/shared/oopStorageParState.hpp"
+#include "gc/shared/oopStorageSetParState.hpp"
 #include "gc/shared/suspendibleThreadSet.hpp"
 #include "memory/allocation.hpp"
 #include "memory/iterator.hpp"
@@ -35,6 +36,7 @@
 class ZRootsIteratorClosure;
 
 typedef OopStorage::ParState<true /* concurrent */, false /* is_const */> ZOopStorageIterator;
+typedef OopStorageSetStrongParState<true /* concurrent */, false /* is_const */> ZOopStorageSetIterator;
 
 template <typename T, void (T::*F)(ZRootsIteratorClosure*)>
 class ZSerialOopsDo {
@@ -134,16 +136,13 @@
 
 class ZConcurrentRootsIterator {
 private:
-  ZOopStorageIterator _jni_handles_iter;
-  ZOopStorageIterator _vm_handles_iter;
-  const int           _cld_claim;
+  ZOopStorageSetIterator _oop_storage_set_iter;
+  const int              _cld_claim;
 
-  void do_jni_handles(ZRootsIteratorClosure* cl);
-  void do_vm_handles(ZRootsIteratorClosure* cl);
+  void do_oop_storage_set(ZRootsIteratorClosure* cl);
   void do_class_loader_data_graph(ZRootsIteratorClosure* cl);
 
-  ZParallelOopsDo<ZConcurrentRootsIterator, &ZConcurrentRootsIterator::do_jni_handles>             _jni_handles;
-  ZParallelOopsDo<ZConcurrentRootsIterator, &ZConcurrentRootsIterator::do_vm_handles>              _vm_handles;
+  ZParallelOopsDo<ZConcurrentRootsIterator, &ZConcurrentRootsIterator::do_oop_storage_set>         _oop_storage_set;
   ZParallelOopsDo<ZConcurrentRootsIterator, &ZConcurrentRootsIterator::do_class_loader_data_graph> _class_loader_data_graph;
 
 public:
--- /dev/null	2020-06-11 14:40:13.671999880 +0200
+++ new/src/hotspot/share/gc/shared/oopStorageSetParState.hpp	2020-06-24 11:28:31.541121958 +0200
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_HPP
+#define SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_HPP
+
+#include "gc/shared/oopStorageParState.hpp"
+#include "gc/shared/oopStorageSet.hpp"
+#include "utilities/valueObjArray.hpp"
+
+template <bool concurrent, bool is_const>
+class OopStorageSetStrongParState {
+  typedef OopStorage::ParState<concurrent, is_const> ParStateType;
+  typedef ValueObjArray<ParStateType, OopStorageSet::strong_count> ParStateArray;
+
+  ParStateArray _par_states;
+
+public:
+  OopStorageSetStrongParState();
+
+  template <typename Closure>
+  void oops_do(Closure* cl);
+};
+
+#endif // SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_HPP
--- /dev/null	2020-06-11 14:40:13.671999880 +0200
+++ new/src/hotspot/share/gc/shared/oopStorageSetParState.inline.hpp	2020-06-24 11:28:31.865128326 +0200
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_INLINE_HPP
+#define SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_INLINE_HPP
+
+#include "gc/shared/oopStorageParState.inline.hpp"
+#include "gc/shared/oopStorageSet.hpp"
+#include "gc/shared/oopStorageSetParState.hpp"
+
+template <bool concurrent, bool is_const>
+OopStorageSetStrongParState<concurrent, is_const>::OopStorageSetStrongParState() :
+    _par_states(OopStorageSet::strong_iterator()) {
+}
+
+template <bool concurrent, bool is_const>
+template <typename Closure>
+void OopStorageSetStrongParState<concurrent, is_const>::oops_do(Closure* cl) {
+  for (int i = 0; i < _par_states.count(); i++) {
+    _par_states.at(i)->oops_do(cl);
+  }
+}
+
+
+#endif // SHARE_GC_SHARED_OOPSTORAGESETPARSTATE_INLINE_HPP
--- /dev/null	2020-06-11 14:40:13.671999880 +0200
+++ new/src/hotspot/share/utilities/valueObjArray.hpp	2020-06-24 11:28:32.197134850 +0200
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_UTILITIES_VALUEOBJARRAY_HPP
+#define SHARE_UTILITIES_VALUEOBJARRAY_HPP
+
+#include "utilities/debug.hpp"
+
+// Stamps out Count instances of Type using a recursive template.
+template <typename Type, int Count>
+class ValueObjBlock {
+  typedef ValueObjBlock<Type, Count - 1> Next;
+
+  Type _instance;
+  Next _next;
+
+public:
+  template <typename Generator>
+  ValueObjBlock(Generator g, Type** save_to) :
+      _instance(*g),
+      _next(++g, save_to + 1) {
+    *save_to = &_instance;
+  }
+};
+
+// Specialization for the recursion base case.
+template <typename Type>
+class ValueObjBlock<Type, 0> {
+public:
+  template <typename Generator>
+  ValueObjBlock(Generator, Type**) {}
+};
+
+// Maps an array of size Count over stamped-out instances of Type.
+template <typename Type, int Count>
+struct ValueObjArray {
+  Type*                      _ptrs[Count];
+  ValueObjBlock<Type, Count> _block;
+
+  template <typename Generator>
+  ValueObjArray(Generator g) : _ptrs(), _block(g, _ptrs) {}
+
+  Type* at(int index) const {
+    assert(0 <= index && index < Count, "index out-of-bounds: %d", index);
+    return _ptrs[index];
+  }
+
+  static int count() {
+    return Count;
+  }
+};
+
+#endif // SHARE_UTILITIES_VALUEOBJARRAY_HPP
--- /dev/null	2020-06-11 14:40:13.671999880 +0200
+++ new/test/hotspot/gtest/utilities/test_valueObjArray.cpp	2020-06-24 11:28:32.481140430 +0200
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "utilities/valueObjArray.hpp"
+#include "unittest.hpp"
+
+class ValueObjArrayTest : public ::testing::Test {
+protected:
+  class IntGenerator {
+    int _current;
+
+  public:
+    IntGenerator() : _current(0) {}
+    int operator*() const {
+      return _current;
+    }
+    IntGenerator operator++() {
+      ++_current;
+      return *this;
+    }
+  };
+
+  struct Struct {
+    int _value;
+    const char* _string;
+  };
+
+  class StructGenerator {
+    int _current;
+
+    static const char* str(int i) {
+      const char* array[] = {
+        "0",
+        "1",
+        "2",
+        "3"};
+      return array[i];
+    }
+
+  public:
+    StructGenerator() : _current(0) {}
+    Struct operator*() const {
+      assert(_current < 4, "precondition");
+      Struct s = { _current, str(_current)};
+      return s;
+    }
+    StructGenerator operator++() {
+      ++_current;
+      return *this;
+    }
+  };
+};
+
+TEST_F(ValueObjArrayTest, primitive) {
+  ValueObjArrayTest::IntGenerator g;
+  ValueObjArray<int, 4> array(g);
+  ASSERT_EQ(array.count(), 4);
+  ASSERT_EQ(*array.at(0), 0);
+  ASSERT_EQ(*array.at(1), 1);
+  ASSERT_EQ(*array.at(2), 2);
+  ASSERT_EQ(*array.at(3), 3);
+}
+
+TEST_F(ValueObjArrayTest, struct) {
+  ValueObjArrayTest::StructGenerator g;
+  ValueObjArray<Struct, 4> array(g);
+  ASSERT_EQ(array.count(), 4);
+  ASSERT_EQ(array.at(0)->_value, 0);
+  ASSERT_EQ(array.at(1)->_value, 1);
+  ASSERT_EQ(array.at(2)->_value, 2);
+  ASSERT_EQ(array.at(3)->_value, 3);
+  ASSERT_EQ(array.at(0)->_string[0], '0');
+  ASSERT_EQ(array.at(1)->_string[0], '1');
+  ASSERT_EQ(array.at(2)->_string[0], '2');
+  ASSERT_EQ(array.at(3)->_string[0], '3');
+}