--- a/src/os/windows/vm/os_windows.cpp	Wed Sep 11 08:57:02 2013 +0200
+++ b/src/os/windows/vm/os_windows.cpp	Wed Sep 11 12:03:41 2013 +0200
@@ -3189,9 +3189,12 @@
     return p_buf;
 
   } else {
+    if (TracePageSizes && Verbose) {
+       tty->print_cr("Reserving large pages in a single large chunk.");
+    }
     // normal policy just allocate it all at once
     DWORD flag = MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES;
-    char * res = (char *)VirtualAlloc(NULL, bytes, flag, prot);
+    char * res = (char *)VirtualAlloc(addr, bytes, flag, prot);
     if (res != NULL) {
       address pc = CALLER_PC;
       MemTracker::record_virtual_memory_reserve_and_commit((address)res, bytes, mtNone, pc);
@@ -5714,7 +5717,66 @@
 #endif
 
 #ifndef PRODUCT
+
+// test the code path in reserve_memory_special() that tries to allocate memory in a single
+// contiguous memory block at a particular address.
+// The test first tries to find a good approximate address to allocate at by using the same
+// method to allocate some memory at any address. The test then tries to allocate memory in
+// the vicinity (not directly after it to avoid possible by-chance use of that location)
+// This is of course only some dodgy assumption, there is no guarantee that the vicinity of
+// the previously allocated memory is available for allocation. The only actual failure
+// that is reported is when the test tries to allocate at a particular location but gets a
+// different valid one. A NULL return value at this point is not considered an error but may
+// be legitimate.
+// If -XX:+VerboseInternalVMTests is enabled, print some explanatory messages.
 void TestReserveMemorySpecial_test() {
-  // No tests available for this platform
-}
-#endif
+  if (!UseLargePages) {
+    if (VerboseInternalVMTests) {
+      gclog_or_tty->print("Skipping test because large pages are disabled");
+    }
+    return;
+  }
+  // save current value of globals
+  bool old_use_large_pages_individual_allocation = UseLargePagesIndividualAllocation;
+  bool old_use_numa_interleaving = UseNUMAInterleaving;
+
+  // set globals to make sure we hit the correct code path
+  UseLargePagesIndividualAllocation = UseNUMAInterleaving = false;
+
+  // do an allocation at an address selected by the OS to get a good one.
+  const size_t large_allocation_size = os::large_page_size() * 4;
+  char* result = os::reserve_memory_special(large_allocation_size, os::large_page_size(), NULL, false);
+  if (result == NULL) {
+    if (VerboseInternalVMTests) {
+      gclog_or_tty->print("Failed to allocate control block with size "SIZE_FORMAT". Skipping remainder of test.",
+        large_allocation_size);
+    }
+  } else {
+    os::release_memory_special(result, large_allocation_size);
+
+    // allocate another page within the recently allocated memory area which seems to be a good location. At least
+    // we managed to get it once.
+    const size_t expected_allocation_size = os::large_page_size();
+    char* expected_location = result + os::large_page_size();
+    char* actual_location = os::reserve_memory_special(expected_allocation_size, os::large_page_size(), expected_location, false);
+    if (actual_location == NULL) {
+      if (VerboseInternalVMTests) {
+        gclog_or_tty->print("Failed to allocate any memory at "PTR_FORMAT" size "SIZE_FORMAT". Skipping remainder of test.",
+          expected_location, large_allocation_size);
+      }
+    } else {
+      // release memory
+      os::release_memory_special(actual_location, expected_allocation_size);
+      // only now check, after releasing any memory to avoid any leaks.
+      assert(actual_location == expected_location,
+        err_msg("Failed to allocate memory at requested location "PTR_FORMAT" of size "SIZE_FORMAT", is "PTR_FORMAT" instead",
+          expected_location, expected_allocation_size, actual_location));
+    }
+  }
+
+  // restore globals
+  UseLargePagesIndividualAllocation = old_use_large_pages_individual_allocation;
+  UseNUMAInterleaving = old_use_numa_interleaving;
+}
+#endif // PRODUCT
+

--- a/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Wed Sep 11 08:57:02 2013 +0200
+++ b/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Wed Sep 11 12:03:41 2013 +0200
@@ -481,9 +481,8 @@
 
 ConcurrentMark::ConcurrentMark(G1CollectedHeap* g1h, ReservedSpace heap_rs) :
   _g1h(g1h),
-  _markBitMap1(MinObjAlignment - 1),
-  _markBitMap2(MinObjAlignment - 1),
-
+  _markBitMap1(log2_intptr(MinObjAlignment)),
+  _markBitMap2(log2_intptr(MinObjAlignment)),
   _parallel_marking_threads(0),
   _max_parallel_marking_threads(0),
   _sleep_factor(0.0),

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/gc/TestObjectAlignment.java	Wed Sep 11 12:03:41 2013 +0200
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2013, 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.
+ */
+
+/**
+ * @test TestObjectAlignment
+ * @key gc
+ * @bug 8021823
+ * @summary G1: Concurrent marking crashes with -XX:ObjectAlignmentInBytes>=32 in 64bit VMs
+ * @library /testlibrary
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=8
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=16
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=32
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=64
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=128
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=256
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=8
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=16
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=32
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=64
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=128
+ * @run main/othervm TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=256
+ */
+
+import com.oracle.java.testlibrary.ProcessTools;
+import com.oracle.java.testlibrary.OutputAnalyzer;
+
+public class TestObjectAlignment {
+
+  public static byte[] garbage;
+
+  private static boolean runsOn32bit() {
+    return System.getProperty("sun.arch.data.model").equals("32");
+  }
+
+  public static void main(String[] args) throws Exception {
+    if (runsOn32bit()) {
+      // 32 bit VMs do not allow setting ObjectAlignmentInBytes, so there is nothing to test. We still get called.
+      return;
+    }
+    for (int i = 0; i < 10; i++) {
+      garbage = new byte[1000];
+      System.gc();
+    }
+  }
+}