--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/src/hotspot/share/gc/z/zCPU.cpp	2018-06-08 19:45:59.796835599 +0200
@@ -0,0 +1,74 @@
+/*
+ * 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/zCPU.hpp"
+#include "logging/log.hpp"
+#include "memory/padded.inline.hpp"
+#include "runtime/os.hpp"
+#include "runtime/thread.inline.hpp"
+#include "utilities/debug.hpp"
+
+#define ZCPU_UNKNOWN_AFFINITY (Thread*)-1;
+#define ZCPU_UNKNOWN_SELF     (Thread*)-2;
+
+PaddedEnd<ZCPU::ZCPUAffinity>* ZCPU::_affinity = NULL;
+__thread Thread*  ZCPU::_self                  = ZCPU_UNKNOWN_SELF;
+__thread uint32_t ZCPU::_cpu                   = 0;
+
+void ZCPU::initialize() {
+  assert(_affinity == NULL, "Already initialized");
+  const uint32_t ncpus = count();
+
+  _affinity = PaddedArray<ZCPUAffinity, mtGC>::create_unfreeable(ncpus);
+
+  for (uint32_t i = 0; i < ncpus; i++) {
+    _affinity[i]._thread = ZCPU_UNKNOWN_AFFINITY;
+  }
+
+  log_info(gc, init)("CPUs: %u total, %u available",
+                     os::processor_count(),
+                     os::initial_active_processor_count());
+}
+
+uint32_t ZCPU::count() {
+  return os::processor_count();
+}
+
+uint32_t ZCPU::id() {
+  assert(_affinity != NULL, "Not initialized");
+
+  // Fast path
+  if (_affinity[_cpu]._thread == _self) {
+    return _cpu;
+  }
+
+  // Slow path
+  _self = Thread::current();
+  _cpu = os::processor_id();
+
+  // Update affinity table
+  _affinity[_cpu]._thread = _self;
+
+  return _cpu;
+}