--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zMemory.cpp	2018-06-06 00:42:03.232106342 +0200
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2015, 2017, 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 "gc/z/zList.inline.hpp"
+#include "gc/z/zMemory.inline.hpp"
+#include "memory/allocation.inline.hpp"
+
+uintptr_t ZMemoryManager::alloc_from_front(size_t size) {
+  ZListIterator<ZMemory> iter(&_freelist);
+  for (ZMemory* area; iter.next(&area);) {
+    if (area->size() >= size) {
+      if (area->size() == size) {
+        // Exact match, remove area
+        const uintptr_t start = area->start();
+        _freelist.remove(area);
+        delete area;
+        return start;
+      } else {
+        // Larger than requested, shrink area
+        const uintptr_t start = area->start();
+        area->shrink_from_front(size);
+        return start;
+      }
+    }
+  }
+
+  // Out of memory
+  return UINTPTR_MAX;
+}
+
+uintptr_t ZMemoryManager::alloc_from_back(size_t size) {
+  ZListReverseIterator<ZMemory> iter(&_freelist);
+  for (ZMemory* area; iter.next(&area);) {
+    if (area->size() >= size) {
+      if (area->size() == size) {
+        // Exact match, remove area
+        const uintptr_t start = area->start();
+        _freelist.remove(area);
+        delete area;
+        return start;
+      } else {
+        // Larger than requested, shrink area
+        area->shrink_from_back(size);
+        return area->end();
+      }
+    }
+  }
+
+  // Out of memory
+  return UINTPTR_MAX;
+}
+
+void ZMemoryManager::free(uintptr_t start, size_t size) {
+  assert(start != UINTPTR_MAX, "Invalid address");
+  const uintptr_t end = start + size;
+
+  ZListIterator<ZMemory> iter(&_freelist);
+  for (ZMemory* area; iter.next(&area);) {
+    if (start < area->start()) {
+      ZMemory* const prev = _freelist.prev(area);
+      if (prev != NULL && start == prev->end()) {
+        if (end == area->start()) {
+          // Merge with prev and current area
+          prev->grow_from_back(size + area->size());
+          _freelist.remove(area);
+          delete area;
+        } else {
+          // Merge with prev area
+          prev->grow_from_back(size);
+        }
+      } else if (end == area->start()) {
+        // Merge with current area
+        area->grow_from_front(size);
+      } else {
+        // Insert new area before current area
+        assert(end < area->start(), "Areas must not overlap");
+        ZMemory* new_area = new ZMemory(start, size);
+        _freelist.insert_before(area, new_area);
+      }
+
+      // Done
+      return;
+    }
+  }
+
+  // Insert last
+  ZMemory* const last = _freelist.last();
+  if (last != NULL && start == last->end()) {
+    // Merge with last area
+    last->grow_from_back(size);
+  } else {
+    // Insert new area last
+    ZMemory* new_area = new ZMemory(start, size);
+    _freelist.insert_last(new_area);
+  }
+}