--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/posix/gc/z/zVirtualMemory_posix.cpp	Thu Oct 17 20:53:35 2019 +0100
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2015, 2019, 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/zAddress.inline.hpp"
+#include "gc/z/zVirtualMemory.hpp"
+#include "logging/log.hpp"
+
+#include <sys/mman.h>
+#include <sys/types.h>
+
+static void unmap(uintptr_t start, size_t size) {
+  const int res = munmap((void*)start, size);
+  assert(res == 0, "Failed to unmap memory");
+}
+
+static bool map(uintptr_t start, size_t size) {
+  const void* const res = mmap((void*)start, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
+  if (res == MAP_FAILED) {
+    // Failed to reserve memory
+    return false;
+  }
+
+  if ((uintptr_t)res != start) {
+    // Failed to reserve memory at the requested address
+    unmap((uintptr_t)res, size);
+    return false;
+  }
+
+  // Success
+  return true;
+}
+
+bool ZVirtualMemoryManager::reserve_platform(uintptr_t start, size_t size) {
+  // Reserve address views
+  const uintptr_t marked0 = ZAddress::marked0(start);
+  const uintptr_t marked1 = ZAddress::marked1(start);
+  const uintptr_t remapped = ZAddress::remapped(start);
+
+  if (!map(marked0, size)) {
+    return false;
+  }
+
+  if (!map(marked1, size)) {
+    unmap(marked0, size);
+    return false;
+  }
+
+  if (!map(remapped, size)) {
+    unmap(marked0, size);
+    unmap(marked1, size);
+    return false;
+  }
+
+  // Register address views with native memory tracker
+  nmt_reserve(marked0, size);
+  nmt_reserve(marked1, size);
+  nmt_reserve(remapped, size);
+
+  return true;
+}