--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/waitBarrier_linux.cpp	Fri Jan 11 10:58:46 2019 +0100
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 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/precompiled.hpp"
+#include "runtime/orderAccess.hpp"
+#include "runtime/os.hpp"
+#include "waitBarrier_linux.hpp"
+#include <sys/syscall.h>
+#include <linux/futex.h>
+
+#define check_with_errno(check_type, cond, msg)                             \
+  do {                                                                      \
+    int err = errno;                                                        \
+    check_type(cond, "%s: error='%s' (errno=%s)", msg, os::strerror(err),   \
+               os::errno_name(err));                                        \
+} while (false)
+
+#define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
+
+static int futex(volatile int *addr, int futex_op, int op_arg) {
+  return syscall(SYS_futex, addr, futex_op, op_arg, NULL, NULL, 0);
+}
+
+void LinuxWaitBarrier::arm(int barrier_tag) {
+  assert(_futex_barrier == 0, "Should not be already armed: "
+         "_futex_barrier=%d", _futex_barrier);
+  _futex_barrier = barrier_tag;
+  OrderAccess::fence();
+}
+
+void LinuxWaitBarrier::disarm() {
+  assert(_futex_barrier != 0, "Should be armed/non-zero.");
+  _futex_barrier = 0;
+  int s = futex(&_futex_barrier,
+                FUTEX_WAKE_PRIVATE,
+                INT_MAX /* wake a max of this many threads */);
+  guarantee_with_errno(s > -1, "futex FUTEX_WAKE failed");
+}
+
+void LinuxWaitBarrier::wait(int barrier_tag) {
+  assert(barrier_tag != 0, "Trying to wait on disarmed value");
+  if (barrier_tag == 0 ||
+      barrier_tag != _futex_barrier) {
+    OrderAccess::fence();
+    return;
+  }
+  do {
+    int s = futex(&_futex_barrier,
+                  FUTEX_WAIT_PRIVATE,
+                  barrier_tag /* should be this tag */);
+    guarantee_with_errno((s == 0) ||
+                         (s == -1 && errno == EAGAIN) ||
+                         (s == -1 && errno == EINTR),
+                         "futex FUTEX_WAIT failed");
+    // Return value 0: woken up, but re-check in case of spurious wakeup.
+    // Error EINTR: woken by signal, so re-check and re-wait if necessary.
+    // Error EAGAIN: we are already disarmed and so will pass the check.
+  } while (barrier_tag == _futex_barrier);
+}