diff --git a/make/excludeSrc.make b/make/excludeSrc.make
index c3a9b4dea0ee2a7ceb7fbb6f5fc7ad9d8362031f..a95dc1b114cf5d47adb77dafdbac9c66cb2969d9 100644
--- a/make/excludeSrc.make
+++ b/make/excludeSrc.make
@@ -88,7 +88,7 @@ ifeq ($(INCLUDE_ALL_GCS), false)
 	g1ErgoVerbose.cpp g1GCPhaseTimes.cpp g1HRPrinter.cpp g1HotCardCache.cpp g1Log.cpp \
 	g1MMUTracker.cpp g1MarkSweep.cpp g1MemoryPool.cpp g1MonitoringSupport.cpp \
 	g1RemSet.cpp g1RemSetSummary.cpp g1SATBCardTableModRefBS.cpp g1_globals.cpp heapRegion.cpp \
-	heapRegionRemSet.cpp heapRegionSeq.cpp heapRegionSet.cpp heapRegionSets.cpp \
+	g1BiasedArray.cpp heapRegionRemSet.cpp heapRegionSeq.cpp heapRegionSet.cpp heapRegionSets.cpp \
 	ptrQueue.cpp satbQueue.cpp sparsePRT.cpp survRateGroup.cpp vm_operations_g1.cpp \
 	adjoiningGenerations.cpp adjoiningVirtualSpaces.cpp asPSOldGen.cpp asPSYoungGen.cpp \
 	cardTableExtension.cpp gcTaskManager.cpp gcTaskThread.cpp objectStartArray.cpp \
diff --git a/src/share/vm/classfile/symbolTable.cpp b/src/share/vm/classfile/symbolTable.cpp
index 747ca870c2b5f863f567a1a1d40da40545b57612..62988c7bf4a925354ccd92c1182bafabc5a24797 100644
--- a/src/share/vm/classfile/symbolTable.cpp
+++ b/src/share/vm/classfile/symbolTable.cpp
@@ -341,7 +341,7 @@ Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) {
 
 Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len,
                                unsigned int hashValue_arg, bool c_heap, TRAPS) {
-  assert(!Universe::heap()->is_in_reserved(name) || GC_locker::is_active(),
+  assert(!Universe::heap()->is_in_reserved(name),
          "proposed name of symbol must be stable");
 
   // Don't allow symbols to be created which cannot fit in a Symbol*.
@@ -685,7 +685,7 @@ oop StringTable::intern(Handle string_or_null, jchar* name,
   if (found_string != NULL) return found_string;
 
   debug_only(StableMemoryChecker smc(name, len * sizeof(name[0])));
-  assert(!Universe::heap()->is_in_reserved(name) || GC_locker::is_active(),
+  assert(!Universe::heap()->is_in_reserved(name),
          "proposed name of symbol must be stable");
 
   Handle string;
diff --git a/src/share/vm/gc_implementation/g1/g1BiasedArray.cpp b/src/share/vm/gc_implementation/g1/g1BiasedArray.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7f5023b422bf893f156f9d52e563350f158dbc6c
--- /dev/null
+++ b/src/share/vm/gc_implementation/g1/g1BiasedArray.cpp
@@ -0,0 +1,141 @@
+/*
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/g1/g1BiasedArray.hpp"
+
+#ifndef PRODUCT
+void G1BiasedMappedArrayBase::verify_index(idx_t index) const {
+  guarantee(_base != NULL, "Array not initialized");
+  guarantee(index < length(), err_msg("Index out of bounds index: "SIZE_FORMAT" length: "SIZE_FORMAT, index, length()));
+}
+
+void G1BiasedMappedArrayBase::verify_biased_index(idx_t biased_index) const {
+  guarantee(_biased_base != NULL, "Array not initialized");
+  guarantee(biased_index >= bias() && biased_index < (bias() + length()),
+    err_msg("Biased index out of bounds, index: "SIZE_FORMAT" bias: "SIZE_FORMAT" length: "SIZE_FORMAT, biased_index, bias(), length()));
+}
+
+void G1BiasedMappedArrayBase::verify_biased_index_inclusive_end(idx_t biased_index) const {
+  guarantee(_biased_base != NULL, "Array not initialized");
+  guarantee(biased_index >= bias() && biased_index <= (bias() + length()),
+    err_msg("Biased index out of inclusive bounds, index: "SIZE_FORMAT" bias: "SIZE_FORMAT" length: "SIZE_FORMAT, biased_index, bias(), length()));
+}
+
+class TestMappedArray : public G1BiasedMappedArray<int> {
+protected:
+  virtual int default_value() const { return 0xBAADBABE; }
+public:
+  static void test_biasedarray() {
+    const size_t REGION_SIZE_IN_WORDS = 512;
+    const size_t NUM_REGIONS = 20;
+    HeapWord* fake_heap = (HeapWord*)LP64_ONLY(0xBAAA00000) NOT_LP64(0xBA000000); // Any value that is non-zero
+
+    TestMappedArray array;
+    array.initialize(fake_heap, fake_heap + REGION_SIZE_IN_WORDS * NUM_REGIONS,
+            REGION_SIZE_IN_WORDS * HeapWordSize);
+    // Check address calculation (bounds)
+    assert(array.bottom_address_mapped() == fake_heap,
+      err_msg("bottom mapped address should be "PTR_FORMAT", but is "PTR_FORMAT, fake_heap, array.bottom_address_mapped()));
+    assert(array.end_address_mapped() == (fake_heap + REGION_SIZE_IN_WORDS * NUM_REGIONS), "must be");
+
+    int* bottom = array.address_mapped_to(fake_heap);
+    assert((void*)bottom == (void*) array.base(), "must be");
+    int* end = array.address_mapped_to(fake_heap + REGION_SIZE_IN_WORDS * NUM_REGIONS);
+    assert((void*)end == (void*)(array.base() + array.length()), "must be");
+    // The entire array should contain default value elements
+    for (int* current = bottom; current < end; current++) {
+      assert(*current == array.default_value(), "must be");
+    }
+
+    // Test setting values in the table
+
+    HeapWord* region_start_address = fake_heap + REGION_SIZE_IN_WORDS * (NUM_REGIONS / 2);
+    HeapWord* region_end_address = fake_heap + (REGION_SIZE_IN_WORDS * (NUM_REGIONS / 2) + REGION_SIZE_IN_WORDS - 1);
+
+    // Set/get by address tests: invert some value; first retrieve one
+    int actual_value = array.get_by_index(NUM_REGIONS / 2);
+    array.set_by_index(NUM_REGIONS / 2, ~actual_value);
+    // Get the same value by address, should correspond to the start of the "region"
+    int value = array.get_by_address(region_start_address);
+    assert(value == ~actual_value, "must be");
+    // Get the same value by address, at one HeapWord before the start
+    value = array.get_by_address(region_start_address - 1);
+    assert(value == array.default_value(), "must be");
+    // Get the same value by address, at the end of the "region"
+    value = array.get_by_address(region_end_address);
+    assert(value == ~actual_value, "must be");
+    // Make sure the next value maps to another index
+    value = array.get_by_address(region_end_address + 1);
+    assert(value == array.default_value(), "must be");
+
+    // Reset the value in the array
+    array.set_by_address(region_start_address + (region_end_address - region_start_address) / 2, actual_value);
+
+    // The entire array should have the default value again
+    for (int* current = bottom; current < end; current++) {
+      assert(*current == array.default_value(), "must be");
+    }
+
+    // Set/get by index tests: invert some value
+    idx_t index = NUM_REGIONS / 2;
+    actual_value = array.get_by_index(index);
+    array.set_by_index(index, ~actual_value);
+
+    value = array.get_by_index(index);
+    assert(value == ~actual_value, "must be");
+
+    value = array.get_by_index(index - 1);
+    assert(value == array.default_value(), "must be");
+
+    value = array.get_by_index(index + 1);
+    assert(value == array.default_value(), "must be");
+
+    array.set_by_index(0, 0);
+    value = array.get_by_index(0);
+    assert(value == 0, "must be");
+
+    array.set_by_index(array.length() - 1, 0);
+    value = array.get_by_index(array.length() - 1);
+    assert(value == 0, "must be");
+
+    array.set_by_index(index, 0);
+
+    // The array should have three zeros, and default values otherwise
+    size_t num_zeros = 0;
+    for (int* current = bottom; current < end; current++) {
+      assert(*current == array.default_value() || *current == 0, "must be");
+      if (*current == 0) {
+        num_zeros++;
+      }
+    }
+    assert(num_zeros == 3, "must be");
+  }
+};
+
+void TestG1BiasedArray_test() {
+  TestMappedArray::test_biasedarray();
+}
+
+#endif
diff --git a/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp b/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..f80c70b4e36935db709bf68d9f2138fb9be7dbe9
--- /dev/null
+++ b/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp
@@ -0,0 +1,181 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
+
+#include "utilities/debug.hpp"
+#include "memory/allocation.inline.hpp"
+
+// Implements the common base functionality for arrays that contain provisions
+// for accessing its elements using a biased index.
+// The element type is defined by the instantiating the template.
+class G1BiasedMappedArrayBase VALUE_OBJ_CLASS_SPEC {
+  friend class VMStructs;
+public:
+  typedef size_t idx_t;
+protected:
+  address _base;          // the real base address
+  size_t _length;         // the length of the array
+  address _biased_base;   // base address biased by "bias" elements
+  size_t _bias;           // the bias, i.e. the offset biased_base is located to the right in elements
+  uint _shift_by;         // the amount of bits to shift right when mapping to an index of the array.
+
+protected:
+
+  G1BiasedMappedArrayBase() : _base(NULL), _length(0), _biased_base(NULL),
+    _bias(0), _shift_by(0) { }
+
+  // Allocate a new array, generic version.
+  static address create_new_base_array(size_t length, size_t elem_size) {
+    assert(length > 0, "just checking");
+    assert(elem_size > 0, "just checking");
+    return NEW_C_HEAP_ARRAY(u_char, length * elem_size, mtGC);
+  }
+
+  // Initialize the members of this class. The biased start address of this array
+  // is the bias (in elements) multiplied by the element size.
+  void initialize_base(address base, size_t length, size_t bias, size_t elem_size, uint shift_by) {
+    assert(base != NULL, "just checking");
+    assert(length > 0, "just checking");
+    assert(shift_by < sizeof(uintptr_t) * 8, err_msg("Shifting by %zd, larger than word size?", shift_by));
+    _base = base;
+    _length = length;
+    _biased_base = base - (bias * elem_size);
+    _bias = bias;
+    _shift_by = shift_by;
+  }
+
+  // Allocate and initialize this array to cover the heap addresses in the range
+  // of [bottom, end).
+  void initialize(HeapWord* bottom, HeapWord* end, size_t target_elem_size_in_bytes, size_t mapping_granularity_in_bytes) {
+    assert(mapping_granularity_in_bytes > 0, "just checking");
+    assert(is_power_of_2(mapping_granularity_in_bytes),
+      err_msg("mapping granularity must be power of 2, is %zd", mapping_granularity_in_bytes));
+    assert((uintptr_t)bottom % mapping_granularity_in_bytes == 0,
+      err_msg("bottom mapping area address must be a multiple of mapping granularity %zd, is "PTR_FORMAT,
+        mapping_granularity_in_bytes, bottom));
+    assert((uintptr_t)end % mapping_granularity_in_bytes == 0,
+      err_msg("end mapping area address must be a multiple of mapping granularity %zd, is "PTR_FORMAT,
+        mapping_granularity_in_bytes, end));
+    size_t num_target_elems = (end - bottom) / (mapping_granularity_in_bytes / HeapWordSize);
+    idx_t bias = (uintptr_t)bottom / mapping_granularity_in_bytes;
+    address base = create_new_base_array(num_target_elems, target_elem_size_in_bytes);
+    initialize_base(base, num_target_elems, bias, target_elem_size_in_bytes, log2_intptr(mapping_granularity_in_bytes));
+  }
+
+  size_t bias() const { return _bias; }
+  uint shift_by() const { return _shift_by; }
+
+  void verify_index(idx_t index) const PRODUCT_RETURN;
+  void verify_biased_index(idx_t biased_index) const PRODUCT_RETURN;
+  void verify_biased_index_inclusive_end(idx_t biased_index) const PRODUCT_RETURN;
+
+public:
+   // Return the length of the array in elements.
+   size_t length() const { return _length; }
+};
+
+// Array that provides biased access and mapping from (valid) addresses in the
+// heap into this array.
+template<class T>
+class G1BiasedMappedArray : public G1BiasedMappedArrayBase {
+public:
+  typedef G1BiasedMappedArrayBase::idx_t idx_t;
+
+  T* base() const { return (T*)G1BiasedMappedArrayBase::_base; }
+  // Return the element of the given array at the given index. Assume
+  // the index is valid. This is a convenience method that does sanity
+  // checking on the index.
+  T get_by_index(idx_t index) const {
+    verify_index(index);
+    return this->base()[index];
+  }
+
+  // Set the element of the given array at the given index to the
+  // given value. Assume the index is valid. This is a convenience
+  // method that does sanity checking on the index.
+  void set_by_index(idx_t index, T value) {
+    verify_index(index);
+    this->base()[index] = value;
+  }
+
+  // The raw biased base pointer.
+  T* biased_base() const { return (T*)G1BiasedMappedArrayBase::_biased_base; }
+
+  // Return the element of the given array that covers the given word in the
+  // heap. Assumes the index is valid.
+  T get_by_address(HeapWord* value) const {
+    idx_t biased_index = ((uintptr_t)value) >> this->shift_by();
+    this->verify_biased_index(biased_index);
+    return biased_base()[biased_index];
+  }
+
+  // Set the value of the array entry that corresponds to the given array.
+  void set_by_address(HeapWord * address, T value) {
+    idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
+    this->verify_biased_index(biased_index);
+    biased_base()[biased_index] = value;
+  }
+
+protected:
+  // Returns the address of the element the given address maps to
+  T* address_mapped_to(HeapWord* address) {
+    idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
+    this->verify_biased_index_inclusive_end(biased_index);
+    return biased_base() + biased_index;
+  }
+
+public:
+  // Return the smallest address (inclusive) in the heap that this array covers.
+  HeapWord* bottom_address_mapped() const {
+    return (HeapWord*) ((uintptr_t)this->bias() << this->shift_by());
+  }
+
+  // Return the highest address (exclusive) in the heap that this array covers.
+  HeapWord* end_address_mapped() const {
+    return (HeapWord*) ((uintptr_t)(this->bias() + this->length()) << this->shift_by());
+  }
+
+protected:
+  virtual T default_value() const = 0;
+  // Set all elements of the given array to the given value.
+  void clear() {
+    T value = default_value();
+    for (idx_t i = 0; i < length(); i++) {
+      set_by_index(i, value);
+    }
+  }
+public:
+  G1BiasedMappedArray() {}
+
+  // Allocate and initialize this array to cover the heap addresses in the range
+  // of [bottom, end).
+  void initialize(HeapWord* bottom, HeapWord* end, size_t mapping_granularity) {
+    G1BiasedMappedArrayBase::initialize(bottom, end, sizeof(T), mapping_granularity);
+    this->clear();
+  }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
diff --git a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
index 1d8ff8a26dc959ba1eec0121841dc77c91d493a2..0ecfd3ab3bb9bbcf314464b650295f2b24ecb9f8 100644
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
@@ -2069,8 +2069,10 @@ jint G1CollectedHeap::initialize() {
   _g1_storage.initialize(g1_rs, 0);
   _g1_committed = MemRegion((HeapWord*)_g1_storage.low(), (size_t) 0);
   _hrs.initialize((HeapWord*) _g1_reserved.start(),
-                  (HeapWord*) _g1_reserved.end(),
-                  _expansion_regions);
+                  (HeapWord*) _g1_reserved.end());
+  assert(_hrs.max_length() == _expansion_regions,
+         err_msg("max length: %u expansion regions: %u",
+                 _hrs.max_length(), _expansion_regions));
 
   // Do later initialization work for concurrent refinement.
   _cg1r->init();
diff --git a/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp b/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
index dade3dfdfcf79a88a47b45c7055f298662bf41e2..eaa8e10f38d41d42ed208216ef92a708fd8dd733 100644
--- a/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
+++ b/src/share/vm/gc_implementation/g1/heapRegionSeq.cpp
@@ -71,27 +71,16 @@ uint HeapRegionSeq::find_contiguous_from(uint from, uint num) {
 
 // Public
 
-void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end,
-                               uint max_length) {
+void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end) {
   assert((uintptr_t) bottom % HeapRegion::GrainBytes == 0,
          "bottom should be heap region aligned");
   assert((uintptr_t) end % HeapRegion::GrainBytes == 0,
          "end should be heap region aligned");
 
-  _length = 0;
-  _heap_bottom = bottom;
-  _heap_end = end;
-  _region_shift = HeapRegion::LogOfHRGrainBytes;
   _next_search_index = 0;
   _allocated_length = 0;
-  _max_length = max_length;
 
-  _regions = NEW_C_HEAP_ARRAY(HeapRegion*, max_length, mtGC);
-  memset(_regions, 0, (size_t) max_length * sizeof(HeapRegion*));
-  _regions_biased = _regions - ((uintx) bottom >> _region_shift);
-
-  assert(&_regions[0] == &_regions_biased[addr_to_index_biased(bottom)],
-         "bottom should be included in the region with index 0");
+  _regions.initialize(bottom, end, HeapRegion::GrainBytes);
 }
 
 MemRegion HeapRegionSeq::expand_by(HeapWord* old_end,
@@ -101,15 +90,15 @@ MemRegion HeapRegionSeq::expand_by(HeapWord* old_end,
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 
   HeapWord* next_bottom = old_end;
-  assert(_heap_bottom <= next_bottom, "invariant");
+  assert(heap_bottom() <= next_bottom, "invariant");
   while (next_bottom < new_end) {
-    assert(next_bottom < _heap_end, "invariant");
+    assert(next_bottom < heap_end(), "invariant");
     uint index = length();
 
-    assert(index < _max_length, "otherwise we cannot expand further");
+    assert(index < max_length(), "otherwise we cannot expand further");
     if (index == 0) {
       // We have not allocated any regions so far
-      assert(next_bottom == _heap_bottom, "invariant");
+      assert(next_bottom == heap_bottom(), "invariant");
     } else {
       // next_bottom should match the end of the last/previous region
       assert(next_bottom == at(index - 1)->end(), "invariant");
@@ -122,8 +111,8 @@ MemRegion HeapRegionSeq::expand_by(HeapWord* old_end,
         // allocation failed, we bail out and return what we have done so far
         return MemRegion(old_end, next_bottom);
       }
-      assert(_regions[index] == NULL, "invariant");
-      _regions[index] = new_hr;
+      assert(_regions.get_by_index(index) == NULL, "invariant");
+      _regions.set_by_index(index, new_hr);
       increment_allocated_length();
     }
     // Have to increment the length first, otherwise we will get an
@@ -228,26 +217,26 @@ uint HeapRegionSeq::shrink_by(uint num_regions_to_remove) {
 
 #ifndef PRODUCT
 void HeapRegionSeq::verify_optional() {
-  guarantee(_length <= _allocated_length,
+  guarantee(length() <= _allocated_length,
             err_msg("invariant: _length: %u _allocated_length: %u",
-                    _length, _allocated_length));
-  guarantee(_allocated_length <= _max_length,
+                    length(), _allocated_length));
+  guarantee(_allocated_length <= max_length(),
             err_msg("invariant: _allocated_length: %u _max_length: %u",
-                    _allocated_length, _max_length));
-  guarantee(_next_search_index <= _length,
+                    _allocated_length, max_length()));
+  guarantee(_next_search_index <= length(),
             err_msg("invariant: _next_search_index: %u _length: %u",
-                    _next_search_index, _length));
+                    _next_search_index, length()));
 
-  HeapWord* prev_end = _heap_bottom;
+  HeapWord* prev_end = heap_bottom();
   for (uint i = 0; i < _allocated_length; i += 1) {
-    HeapRegion* hr = _regions[i];
+    HeapRegion* hr = _regions.get_by_index(i);
     guarantee(hr != NULL, err_msg("invariant: i: %u", i));
     guarantee(hr->bottom() == prev_end,
               err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT,
                       i, HR_FORMAT_PARAMS(hr), prev_end));
     guarantee(hr->hrs_index() == i,
               err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index()));
-    if (i < _length) {
+    if (i < length()) {
       // Asserts will fire if i is >= _length
       HeapWord* addr = hr->bottom();
       guarantee(addr_to_region(addr) == hr, "sanity");
@@ -265,8 +254,8 @@ void HeapRegionSeq::verify_optional() {
       prev_end = hr->end();
     }
   }
-  for (uint i = _allocated_length; i < _max_length; i += 1) {
-    guarantee(_regions[i] == NULL, err_msg("invariant i: %u", i));
+  for (uint i = _allocated_length; i < max_length(); i += 1) {
+    guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i));
   }
 }
 #endif // PRODUCT
diff --git a/src/share/vm/gc_implementation/g1/heapRegionSeq.hpp b/src/share/vm/gc_implementation/g1/heapRegionSeq.hpp
index b7a58f76a7ff76d90ed822cd19b77c78f290e80d..b0c3eb48a0b3e465d05038547846010c440f7b6a 100644
--- a/src/share/vm/gc_implementation/g1/heapRegionSeq.hpp
+++ b/src/share/vm/gc_implementation/g1/heapRegionSeq.hpp
@@ -25,10 +25,17 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP
 
+#include "gc_implementation/g1/g1BiasedArray.hpp"
+
 class HeapRegion;
 class HeapRegionClosure;
 class FreeRegionList;
 
+class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
+ protected:
+   virtual HeapRegion* default_value() const { return NULL; }
+};
+
 // This class keeps track of the region metadata (i.e., HeapRegion
 // instances). They are kept in the _regions array in address
 // order. A region's index in the array corresponds to its index in
@@ -44,35 +51,21 @@ class FreeRegionList;
 //
 // We keep track of three lengths:
 //
-// * _length (returned by length()) is the number of currently
+// * _committed_length (returned by length()) is the number of currently
 //   committed regions.
 // * _allocated_length (not exposed outside this class) is the
 //   number of regions for which we have HeapRegions.
-// * _max_length (returned by max_length()) is the maximum number of
-//   regions the heap can have.
+// * max_length() returns the maximum number of regions the heap can have.
 //
-// and maintain that: _length <= _allocated_length <= _max_length
+// and maintain that: _committed_length <= _allocated_length <= max_length()
 
 class HeapRegionSeq: public CHeapObj<mtGC> {
   friend class VMStructs;
 
-  // The array that holds the HeapRegions.
-  HeapRegion** _regions;
-
-  // Version of _regions biased to address 0
-  HeapRegion** _regions_biased;
+  G1HeapRegionTable _regions;
 
   // The number of regions committed in the heap.
-  uint _length;
-
-  // The address of the first reserved word in the heap.
-  HeapWord* _heap_bottom;
-
-  // The address of the last reserved word in the heap - 1.
-  HeapWord* _heap_end;
-
-  // The log of the region byte size.
-  uint _region_shift;
+  uint _committed_length;
 
   // A hint for which index to start searching from for humongous
   // allocations.
@@ -81,37 +74,33 @@ class HeapRegionSeq: public CHeapObj<mtGC> {
   // The number of regions for which we have allocated HeapRegions for.
   uint _allocated_length;
 
-  // The maximum number of regions in the heap.
-  uint _max_length;
-
   // Find a contiguous set of empty regions of length num, starting
   // from the given index.
   uint find_contiguous_from(uint from, uint num);
 
-  // Map a heap address to a biased region index. Assume that the
-  // address is valid.
-  inline uintx addr_to_index_biased(HeapWord* addr) const;
-
   void increment_allocated_length() {
-    assert(_allocated_length < _max_length, "pre-condition");
+    assert(_allocated_length < max_length(), "pre-condition");
     _allocated_length++;
   }
 
   void increment_length() {
-    assert(_length < _max_length, "pre-condition");
-    _length++;
+    assert(length() < max_length(), "pre-condition");
+    _committed_length++;
   }
 
   void decrement_length() {
-    assert(_length > 0, "pre-condition");
-    _length--;
+    assert(length() > 0, "pre-condition");
+    _committed_length--;
   }
 
+  HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }
+  HeapWord* heap_end() const {return _regions.end_address_mapped(); }
+
  public:
   // Empty contructor, we'll initialize it with the initialize() method.
-  HeapRegionSeq() { }
+  HeapRegionSeq() : _regions(), _committed_length(0), _next_search_index(0), _allocated_length(0) { }
 
-  void initialize(HeapWord* bottom, HeapWord* end, uint max_length);
+  void initialize(HeapWord* bottom, HeapWord* end);
 
   // Return the HeapRegion at the given index. Assume that the index
   // is valid.
@@ -126,10 +115,10 @@ class HeapRegionSeq: public CHeapObj<mtGC> {
   inline HeapRegion* addr_to_region_unsafe(HeapWord* addr) const;
 
   // Return the number of regions that have been committed in the heap.
-  uint length() const { return _length; }
+  uint length() const { return _committed_length; }
 
   // Return the maximum number of regions in the heap.
-  uint max_length() const { return _max_length; }
+  uint max_length() const { return (uint)_regions.length(); }
 
   // Expand the sequence to reflect that the heap has grown from
   // old_end to new_end. Either create new HeapRegions, or re-use
diff --git a/src/share/vm/gc_implementation/g1/heapRegionSeq.inline.hpp b/src/share/vm/gc_implementation/g1/heapRegionSeq.inline.hpp
index e840287edc7b62781608d0fbd1b2e2346ebc8576..96588dea042992d286121770690aedd6b5b9fdbb 100644
--- a/src/share/vm/gc_implementation/g1/heapRegionSeq.inline.hpp
+++ b/src/share/vm/gc_implementation/g1/heapRegionSeq.inline.hpp
@@ -28,28 +28,16 @@
 #include "gc_implementation/g1/heapRegion.hpp"
 #include "gc_implementation/g1/heapRegionSeq.hpp"
 
-inline uintx HeapRegionSeq::addr_to_index_biased(HeapWord* addr) const {
-  assert(_heap_bottom <= addr && addr < _heap_end,
-         err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT" end: "PTR_FORMAT,
-                 addr, _heap_bottom, _heap_end));
-  uintx index = (uintx) addr >> _region_shift;
-  return index;
-}
-
 inline HeapRegion* HeapRegionSeq::addr_to_region_unsafe(HeapWord* addr) const {
-  assert(_heap_bottom <= addr && addr < _heap_end,
-         err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT" end: "PTR_FORMAT,
-                 addr, _heap_bottom, _heap_end));
-  uintx index_biased = addr_to_index_biased(addr);
-  HeapRegion* hr = _regions_biased[index_biased];
+  HeapRegion* hr = _regions.get_by_address(addr);
   assert(hr != NULL, "invariant");
   return hr;
 }
 
 inline HeapRegion* HeapRegionSeq::addr_to_region(HeapWord* addr) const {
-  if (addr != NULL && addr < _heap_end) {
-    assert(addr >= _heap_bottom,
-          err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT, addr, _heap_bottom));
+  if (addr != NULL && addr < heap_end()) {
+    assert(addr >= heap_bottom(),
+          err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT, addr, heap_bottom()));
     return addr_to_region_unsafe(addr);
   }
   return NULL;
@@ -57,7 +45,7 @@ inline HeapRegion* HeapRegionSeq::addr_to_region(HeapWord* addr) const {
 
 inline HeapRegion* HeapRegionSeq::at(uint index) const {
   assert(index < length(), "pre-condition");
-  HeapRegion* hr = _regions[index];
+  HeapRegion* hr = _regions.get_by_index(index);
   assert(hr != NULL, "sanity");
   assert(hr->hrs_index() == index, "sanity");
   return hr;
diff --git a/src/share/vm/gc_implementation/g1/vmStructs_g1.hpp b/src/share/vm/gc_implementation/g1/vmStructs_g1.hpp
index 736c2d7509655ba68822870b94783208f6aba654..9268eb78ef4a973085d334fe390d40374de7d4f5 100644
--- a/src/share/vm/gc_implementation/g1/vmStructs_g1.hpp
+++ b/src/share/vm/gc_implementation/g1/vmStructs_g1.hpp
@@ -34,8 +34,14 @@
   static_field(HeapRegion, GrainBytes,        size_t)                         \
   static_field(HeapRegion, LogOfHRGrainBytes, int)                            \
                                                                               \
-  nonstatic_field(HeapRegionSeq,   _regions, HeapRegion**)                    \
-  nonstatic_field(HeapRegionSeq,   _length,  uint)                            \
+  nonstatic_field(G1HeapRegionTable, _base,             address)              \
+  nonstatic_field(G1HeapRegionTable, _length,           size_t)               \
+  nonstatic_field(G1HeapRegionTable, _biased_base,      address)              \
+  nonstatic_field(G1HeapRegionTable, _bias,             size_t)               \
+  nonstatic_field(G1HeapRegionTable, _shift_by,         uint)                 \
+                                                                              \
+  nonstatic_field(HeapRegionSeq,   _regions,            G1HeapRegionTable)    \
+  nonstatic_field(HeapRegionSeq,   _committed_length,   uint)                 \
                                                                               \
   nonstatic_field(G1CollectedHeap, _hrs,                HeapRegionSeq)        \
   nonstatic_field(G1CollectedHeap, _g1_committed,       MemRegion)            \
@@ -58,6 +64,8 @@
 
 #define VM_TYPES_G1(declare_type, declare_toplevel_type)                      \
                                                                               \
+  declare_toplevel_type(G1HeapRegionTable)                                    \
+                                                                              \
   declare_type(G1CollectedHeap, SharedHeap)                                   \
                                                                               \
   declare_type(HeapRegion, ContiguousSpace)                                   \
diff --git a/src/share/vm/memory/gcLocker.cpp b/src/share/vm/memory/gcLocker.cpp
index eda728b7047ffd37389b54d455c683b62229cb15..1b0c94ee171736fe5e7af41240ef21b97aa1dafe 100644
--- a/src/share/vm/memory/gcLocker.cpp
+++ b/src/share/vm/memory/gcLocker.cpp
@@ -122,7 +122,7 @@ void GC_locker::jni_unlock(JavaThread* thread) {
     // strictly needed. It's added here to make it clear that
     // the GC will NOT be performed if any other caller
     // of GC_locker::lock() still needs GC locked.
-    if (!is_active()) {
+    if (!is_active_internal()) {
       _doing_gc = true;
       {
         // Must give up the lock while at a safepoint
diff --git a/src/share/vm/memory/gcLocker.hpp b/src/share/vm/memory/gcLocker.hpp
index 8ede8fb275b886afe5511bfb5be93fea359908ef..45b8a8f89e718bab6154883edcb534f5a984fabe 100644
--- a/src/share/vm/memory/gcLocker.hpp
+++ b/src/share/vm/memory/gcLocker.hpp
@@ -88,7 +88,7 @@ class GC_locker: public AllStatic {
  public:
   // Accessors
   static bool is_active() {
-    assert(_needs_gc || SafepointSynchronize::is_at_safepoint(), "only read at safepoint");
+    assert(SafepointSynchronize::is_at_safepoint(), "only read at safepoint");
     return is_active_internal();
   }
   static bool needs_gc()       { return _needs_gc;                        }
diff --git a/src/share/vm/memory/metaspace.cpp b/src/share/vm/memory/metaspace.cpp
index c12c0b8637ba3a95b8af3611991e89024b768e23..06f3d09378a24edfc08759d4907ae187bba964f9 100644
--- a/src/share/vm/memory/metaspace.cpp
+++ b/src/share/vm/memory/metaspace.cpp
@@ -23,6 +23,7 @@
  */
 #include "precompiled.hpp"
 #include "gc_interface/collectedHeap.hpp"
+#include "memory/allocation.hpp"
 #include "memory/binaryTreeDictionary.hpp"
 #include "memory/freeList.hpp"
 #include "memory/collectorPolicy.hpp"
@@ -111,7 +112,7 @@ typedef class FreeList<Metachunk> ChunkList;
 // Has three lists of free chunks, and a total size and
 // count that includes all three
 
-class ChunkManager VALUE_OBJ_CLASS_SPEC {
+class ChunkManager : public CHeapObj<mtInternal> {
 
   // Free list of chunks of different sizes.
   //   SpecializedChunk
@@ -158,7 +159,12 @@ class ChunkManager VALUE_OBJ_CLASS_SPEC {
 
  public:
 
-  ChunkManager() : _free_chunks_total(0), _free_chunks_count(0) {}
+  ChunkManager(size_t specialized_size, size_t small_size, size_t medium_size)
+      : _free_chunks_total(0), _free_chunks_count(0) {
+    _free_chunks[SpecializedIndex].set_size(specialized_size);
+    _free_chunks[SmallIndex].set_size(small_size);
+    _free_chunks[MediumIndex].set_size(medium_size);
+  }
 
   // add or delete (return) a chunk to the global freelist.
   Metachunk* chunk_freelist_allocate(size_t word_size);
@@ -219,7 +225,7 @@ class ChunkManager VALUE_OBJ_CLASS_SPEC {
   void locked_print_free_chunks(outputStream* st);
   void locked_print_sum_free_chunks(outputStream* st);
 
-  void print_on(outputStream* st);
+  void print_on(outputStream* st) const;
 };
 
 // Used to manage the free list of Metablocks (a block corresponds
@@ -276,11 +282,6 @@ class VirtualSpaceNode : public CHeapObj<mtClass> {
   // VirtualSpace
   Metachunk* first_chunk() { return (Metachunk*) bottom(); }
 
-  void inc_container_count();
-#ifdef ASSERT
-  uint container_count_slow();
-#endif
-
  public:
 
   VirtualSpaceNode(size_t byte_size);
@@ -314,8 +315,10 @@ class VirtualSpaceNode : public CHeapObj<mtClass> {
   void inc_top(size_t word_size) { _top += word_size; }
 
   uintx container_count() { return _container_count; }
+  void inc_container_count();
   void dec_container_count();
 #ifdef ASSERT
+  uint container_count_slow();
   void verify_container_count();
 #endif
 
@@ -421,8 +424,6 @@ class VirtualSpaceList : public CHeapObj<mtClass> {
   VirtualSpaceNode* _virtual_space_list;
   // virtual space currently being used for allocations
   VirtualSpaceNode* _current_virtual_space;
-  // Free chunk list for all other metadata
-  ChunkManager      _chunk_manager;
 
   // Can this virtual list allocate >1 spaces?  Also, used to determine
   // whether to allocate unlimited small chunks in this virtual space
@@ -475,7 +476,6 @@ class VirtualSpaceList : public CHeapObj<mtClass> {
     return _current_virtual_space;
   }
 
-  ChunkManager* chunk_manager() { return &_chunk_manager; }
   bool is_class() const { return _is_class; }
 
   // Allocate the first virtualspace.
@@ -494,14 +494,7 @@ class VirtualSpaceList : public CHeapObj<mtClass> {
   void dec_virtual_space_count();
 
   // Unlink empty VirtualSpaceNodes and free it.
-  void purge();
-
-  // Used and capacity in the entire list of virtual spaces.
-  // These are global values shared by all Metaspaces
-  size_t capacity_words_sum();
-  size_t capacity_bytes_sum() { return capacity_words_sum() * BytesPerWord; }
-  size_t used_words_sum();
-  size_t used_bytes_sum() { return used_words_sum() * BytesPerWord; }
+  void purge(ChunkManager* chunk_manager);
 
   bool contains(const void *ptr);
 
@@ -582,18 +575,12 @@ class SpaceManager : public CHeapObj<mtClass> {
   // Type of metadata allocated.
   Metaspace::MetadataType _mdtype;
 
-  // Chunk related size
-  size_t _medium_chunk_bunch;
-
   // List of chunks in use by this SpaceManager.  Allocations
   // are done from the current chunk.  The list is used for deallocating
   // chunks when the SpaceManager is freed.
   Metachunk* _chunks_in_use[NumberOfInUseLists];
   Metachunk* _current_chunk;
 
-  // Virtual space where allocation comes from.
-  VirtualSpaceList* _vs_list;
-
   // Number of small chunks to allocate to a manager
   // If class space manager, small chunks are unlimited
   static uint const _small_chunk_limit;
@@ -626,7 +613,9 @@ class SpaceManager : public CHeapObj<mtClass> {
   }
 
   Metaspace::MetadataType mdtype() { return _mdtype; }
-  VirtualSpaceList* vs_list() const    { return _vs_list; }
+
+  VirtualSpaceList* vs_list()   const { return Metaspace::get_space_list(_mdtype); }
+  ChunkManager* chunk_manager() const { return Metaspace::get_chunk_manager(_mdtype); }
 
   Metachunk* current_chunk() const { return _current_chunk; }
   void set_current_chunk(Metachunk* v) {
@@ -648,18 +637,19 @@ class SpaceManager : public CHeapObj<mtClass> {
 
  public:
   SpaceManager(Metaspace::MetadataType mdtype,
-               Mutex* lock,
-               VirtualSpaceList* vs_list);
+               Mutex* lock);
   ~SpaceManager();
 
   enum ChunkMultiples {
     MediumChunkMultiple = 4
   };
 
+  bool is_class() { return _mdtype == Metaspace::ClassType; }
+
   // Accessors
   size_t specialized_chunk_size() { return SpecializedChunk; }
-  size_t small_chunk_size() { return (size_t) vs_list()->is_class() ? ClassSmallChunk : SmallChunk; }
-  size_t medium_chunk_size() { return (size_t) vs_list()->is_class() ? ClassMediumChunk : MediumChunk; }
+  size_t small_chunk_size() { return (size_t) is_class() ? ClassSmallChunk : SmallChunk; }
+  size_t medium_chunk_size() { return (size_t) is_class() ? ClassMediumChunk : MediumChunk; }
   size_t medium_chunk_bunch() { return medium_chunk_size() * MediumChunkMultiple; }
 
   size_t allocated_blocks_words() const { return _allocated_blocks_words; }
@@ -762,7 +752,7 @@ void VirtualSpaceNode::inc_container_count() {
   _container_count++;
   assert(_container_count == container_count_slow(),
          err_msg("Inconsistency in countainer_count _container_count " SIZE_FORMAT
-                 "container_count_slow() " SIZE_FORMAT,
+                 " container_count_slow() " SIZE_FORMAT,
                  _container_count, container_count_slow()));
 }
 
@@ -775,7 +765,7 @@ void VirtualSpaceNode::dec_container_count() {
 void VirtualSpaceNode::verify_container_count() {
   assert(_container_count == container_count_slow(),
     err_msg("Inconsistency in countainer_count _container_count " SIZE_FORMAT
-            "container_count_slow() " SIZE_FORMAT, _container_count, container_count_slow()));
+            " container_count_slow() " SIZE_FORMAT, _container_count, container_count_slow()));
 }
 #endif
 
@@ -1020,7 +1010,7 @@ void ChunkManager::remove_chunk(Metachunk* chunk) {
 // Walk the list of VirtualSpaceNodes and delete
 // nodes with a 0 container_count.  Remove Metachunks in
 // the node from their respective freelists.
-void VirtualSpaceList::purge() {
+void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
   assert_lock_strong(SpaceManager::expand_lock());
   // Don't use a VirtualSpaceListIterator because this
   // list is being changed and a straightforward use of an iterator is not safe.
@@ -1042,7 +1032,7 @@ void VirtualSpaceList::purge() {
         prev_vsl->set_next(vsl->next());
       }
 
-      vsl->purge(chunk_manager());
+      vsl->purge(chunk_manager);
       dec_reserved_words(vsl->reserved_words());
       dec_committed_words(vsl->committed_words());
       dec_virtual_space_count();
@@ -1064,36 +1054,6 @@ void VirtualSpaceList::purge() {
 #endif
 }
 
-size_t VirtualSpaceList::used_words_sum() {
-  size_t allocated_by_vs = 0;
-  VirtualSpaceListIterator iter(virtual_space_list());
-  while (iter.repeat()) {
-    VirtualSpaceNode* vsl = iter.get_next();
-    // Sum used region [bottom, top) in each virtualspace
-    allocated_by_vs += vsl->used_words_in_vs();
-  }
-  assert(allocated_by_vs >= chunk_manager()->free_chunks_total_words(),
-    err_msg("Total in free chunks " SIZE_FORMAT
-            " greater than total from virtual_spaces " SIZE_FORMAT,
-            allocated_by_vs, chunk_manager()->free_chunks_total_words()));
-  size_t used =
-    allocated_by_vs - chunk_manager()->free_chunks_total_words();
-  return used;
-}
-
-// Space available in all MetadataVirtualspaces allocated
-// for metadata.  This is the upper limit on the capacity
-// of chunks allocated out of all the MetadataVirtualspaces.
-size_t VirtualSpaceList::capacity_words_sum() {
-  size_t capacity = 0;
-  VirtualSpaceListIterator iter(virtual_space_list());
-  while (iter.repeat()) {
-    VirtualSpaceNode* vsl = iter.get_next();
-    capacity += vsl->capacity_words_in_vs();
-  }
-  return capacity;
-}
-
 VirtualSpaceList::VirtualSpaceList(size_t word_size ) :
                                    _is_class(false),
                                    _virtual_space_list(NULL),
@@ -1104,10 +1064,6 @@ VirtualSpaceList::VirtualSpaceList(size_t word_size ) :
   MutexLockerEx cl(SpaceManager::expand_lock(),
                    Mutex::_no_safepoint_check_flag);
   bool initialization_succeeded = grow_vs(word_size);
-
-  _chunk_manager.free_chunks(SpecializedIndex)->set_size(SpecializedChunk);
-  _chunk_manager.free_chunks(SmallIndex)->set_size(SmallChunk);
-  _chunk_manager.free_chunks(MediumIndex)->set_size(MediumChunk);
   assert(initialization_succeeded,
     " VirtualSpaceList initialization should not fail");
 }
@@ -1123,9 +1079,6 @@ VirtualSpaceList::VirtualSpaceList(ReservedSpace rs) :
                    Mutex::_no_safepoint_check_flag);
   VirtualSpaceNode* class_entry = new VirtualSpaceNode(rs);
   bool succeeded = class_entry->initialize();
-  _chunk_manager.free_chunks(SpecializedIndex)->set_size(SpecializedChunk);
-  _chunk_manager.free_chunks(SmallIndex)->set_size(ClassSmallChunk);
-  _chunk_manager.free_chunks(MediumIndex)->set_size(ClassMediumChunk);
   assert(succeeded, " VirtualSpaceList initialization should not fail");
   link_vs(class_entry);
 }
@@ -1142,7 +1095,7 @@ bool VirtualSpaceList::grow_vs(size_t vs_word_size) {
   }
   // Reserve the space
   size_t vs_byte_size = vs_word_size * BytesPerWord;
-  assert(vs_byte_size % os::vm_page_size() == 0, "Not aligned");
+  assert(vs_byte_size % os::vm_allocation_granularity() == 0, "Not aligned");
 
   // Allocate the meta virtual space and initialize it.
   VirtualSpaceNode* new_entry = new VirtualSpaceNode(vs_byte_size);
@@ -1195,15 +1148,8 @@ Metachunk* VirtualSpaceList::get_new_chunk(size_t word_size,
                                            size_t grow_chunks_by_words,
                                            size_t medium_chunk_bunch) {
 
-  // Get a chunk from the chunk freelist
-  Metachunk* next = chunk_manager()->chunk_freelist_allocate(grow_chunks_by_words);
-
-  if (next != NULL) {
-    next->container()->inc_container_count();
-  } else {
-    // Allocate a chunk out of the current virtual space.
-    next = current_virtual_space()->get_chunk_vs(grow_chunks_by_words);
-  }
+  // Allocate a chunk out of the current virtual space.
+  Metachunk* next = current_virtual_space()->get_chunk_vs(grow_chunks_by_words);
 
   if (next == NULL) {
     // Not enough room in current virtual space.  Try to commit
@@ -1221,12 +1167,14 @@ Metachunk* VirtualSpaceList::get_new_chunk(size_t word_size,
       // being used for CompressedHeaders, don't allocate a new virtualspace.
       if (can_grow() && MetaspaceGC::should_expand(this, word_size)) {
         // Get another virtual space.
-          size_t grow_vs_words =
-            MAX2((size_t)VirtualSpaceSize, aligned_expand_vs_by_words);
+        size_t allocation_aligned_expand_words =
+            align_size_up(aligned_expand_vs_by_words, os::vm_allocation_granularity() / BytesPerWord);
+        size_t grow_vs_words =
+            MAX2((size_t)VirtualSpaceSize, allocation_aligned_expand_words);
         if (grow_vs(grow_vs_words)) {
           // Got it.  It's on the list now.  Get a chunk from it.
           assert(current_virtual_space()->expanded_words() == 0,
-              "New virtuals space nodes should not have expanded");
+              "New virtual space nodes should not have expanded");
 
           size_t grow_chunks_by_words_aligned = align_size_up(grow_chunks_by_words,
                                                               page_size_words);
@@ -1342,8 +1290,9 @@ bool MetaspaceGC::should_expand(VirtualSpaceList* vsl, size_t word_size) {
   // reserved space, because this is a larger space prereserved for compressed
   // class pointers.
   if (!FLAG_IS_DEFAULT(MaxMetaspaceSize)) {
-    size_t real_allocated = Metaspace::space_list()->reserved_words() +
-              MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
+    size_t nonclass_allocated = MetaspaceAux::reserved_bytes(Metaspace::NonClassType);
+    size_t class_allocated    = MetaspaceAux::allocated_capacity_bytes(Metaspace::ClassType);
+    size_t real_allocated     = nonclass_allocated + class_allocated;
     if (real_allocated >= MaxMetaspaceSize) {
       return false;
     }
@@ -1536,15 +1485,15 @@ void Metadebug::deallocate_chunk_a_lot(SpaceManager* sm,
       if (dummy_chunk == NULL) {
         break;
       }
-      vsl->chunk_manager()->chunk_freelist_deallocate(dummy_chunk);
+      sm->chunk_manager()->chunk_freelist_deallocate(dummy_chunk);
 
       if (TraceMetadataChunkAllocation && Verbose) {
         gclog_or_tty->print("Metadebug::deallocate_chunk_a_lot: %d) ",
                                sm->sum_count_in_chunks_in_use());
         dummy_chunk->print_on(gclog_or_tty);
         gclog_or_tty->print_cr("  Free chunks total %d  count %d",
-                               vsl->chunk_manager()->free_chunks_total_words(),
-                               vsl->chunk_manager()->free_chunks_count());
+                               sm->chunk_manager()->free_chunks_total_words(),
+                               sm->chunk_manager()->free_chunks_count());
       }
     }
   } else {
@@ -1796,6 +1745,8 @@ Metachunk* ChunkManager::free_chunks_get(size_t word_size) {
   // work.
   chunk->set_is_free(false);
 #endif
+  chunk->container()->inc_container_count();
+
   slow_locked_verify();
   return chunk;
 }
@@ -1830,9 +1781,9 @@ Metachunk* ChunkManager::chunk_freelist_allocate(size_t word_size) {
   return chunk;
 }
 
-void ChunkManager::print_on(outputStream* out) {
+void ChunkManager::print_on(outputStream* out) const {
   if (PrintFLSStatistics != 0) {
-    humongous_dictionary()->report_statistics();
+    const_cast<ChunkManager *>(this)->humongous_dictionary()->report_statistics();
   }
 }
 
@@ -1979,8 +1930,8 @@ void SpaceManager::locked_print_chunks_in_use_on(outputStream* st) const {
     }
   }
 
-  vs_list()->chunk_manager()->locked_print_free_chunks(st);
-  vs_list()->chunk_manager()->locked_print_sum_free_chunks(st);
+  chunk_manager()->locked_print_free_chunks(st);
+  chunk_manager()->locked_print_sum_free_chunks(st);
 }
 
 size_t SpaceManager::calc_chunk_size(size_t word_size) {
@@ -2084,9 +2035,7 @@ void SpaceManager::print_on(outputStream* st) const {
 }
 
 SpaceManager::SpaceManager(Metaspace::MetadataType mdtype,
-                           Mutex* lock,
-                           VirtualSpaceList* vs_list) :
-  _vs_list(vs_list),
+                           Mutex* lock) :
   _mdtype(mdtype),
   _allocated_blocks_words(0),
   _allocated_chunks_words(0),
@@ -2172,9 +2121,7 @@ SpaceManager::~SpaceManager() {
   MutexLockerEx fcl(SpaceManager::expand_lock(),
                     Mutex::_no_safepoint_check_flag);
 
-  ChunkManager* chunk_manager = vs_list()->chunk_manager();
-
-  chunk_manager->slow_locked_verify();
+  chunk_manager()->slow_locked_verify();
 
   dec_total_from_size_metrics();
 
@@ -2188,8 +2135,8 @@ SpaceManager::~SpaceManager() {
 
   // Have to update before the chunks_in_use lists are emptied
   // below.
-  chunk_manager->inc_free_chunks_total(allocated_chunks_words(),
-                                       sum_count_in_chunks_in_use());
+  chunk_manager()->inc_free_chunks_total(allocated_chunks_words(),
+                                         sum_count_in_chunks_in_use());
 
   // Add all the chunks in use by this space manager
   // to the global list of free chunks.
@@ -2204,11 +2151,11 @@ SpaceManager::~SpaceManager() {
                              chunk_size_name(i));
     }
     Metachunk* chunks = chunks_in_use(i);
-    chunk_manager->return_chunks(i, chunks);
+    chunk_manager()->return_chunks(i, chunks);
     set_chunks_in_use(i, NULL);
     if (TraceMetadataChunkAllocation && Verbose) {
       gclog_or_tty->print_cr("updated freelist count %d %s",
-                             chunk_manager->free_chunks(i)->count(),
+                             chunk_manager()->free_chunks(i)->count(),
                              chunk_size_name(i));
     }
     assert(i != HumongousIndex, "Humongous chunks are handled explicitly later");
@@ -2245,16 +2192,16 @@ SpaceManager::~SpaceManager() {
                    humongous_chunks->word_size(), HumongousChunkGranularity));
     Metachunk* next_humongous_chunks = humongous_chunks->next();
     humongous_chunks->container()->dec_container_count();
-    chunk_manager->humongous_dictionary()->return_chunk(humongous_chunks);
+    chunk_manager()->humongous_dictionary()->return_chunk(humongous_chunks);
     humongous_chunks = next_humongous_chunks;
   }
   if (TraceMetadataChunkAllocation && Verbose) {
     gclog_or_tty->print_cr("");
     gclog_or_tty->print_cr("updated dictionary count %d %s",
-                     chunk_manager->humongous_dictionary()->total_count(),
+                     chunk_manager()->humongous_dictionary()->total_count(),
                      chunk_size_name(HumongousIndex));
   }
-  chunk_manager->slow_locked_verify();
+  chunk_manager()->slow_locked_verify();
 }
 
 const char* SpaceManager::chunk_size_name(ChunkIndex index) const {
@@ -2343,9 +2290,7 @@ void SpaceManager::add_chunk(Metachunk* new_chunk, bool make_current) {
     gclog_or_tty->print("SpaceManager::add_chunk: %d) ",
                         sum_count_in_chunks_in_use());
     new_chunk->print_on(gclog_or_tty);
-    if (vs_list() != NULL) {
-      vs_list()->chunk_manager()->locked_print_free_chunks(gclog_or_tty);
-    }
+    chunk_manager()->locked_print_free_chunks(gclog_or_tty);
   }
 }
 
@@ -2361,10 +2306,14 @@ void SpaceManager::retire_current_chunk() {
 
 Metachunk* SpaceManager::get_new_chunk(size_t word_size,
                                        size_t grow_chunks_by_words) {
+  // Get a chunk from the chunk freelist
+  Metachunk* next = chunk_manager()->chunk_freelist_allocate(grow_chunks_by_words);
 
-  Metachunk* next = vs_list()->get_new_chunk(word_size,
-                                             grow_chunks_by_words,
-                                             medium_chunk_bunch());
+  if (next == NULL) {
+    next = vs_list()->get_new_chunk(word_size,
+                                    grow_chunks_by_words,
+                                    medium_chunk_bunch());
+  }
 
   if (TraceMetadataHumongousAllocation && next != NULL &&
       SpaceManager::is_humongous(next->word_size())) {
@@ -2644,13 +2593,12 @@ size_t MetaspaceAux::committed_bytes(Metaspace::MetadataType mdtype) {
 size_t MetaspaceAux::min_chunk_size_words() { return Metaspace::first_chunk_word_size(); }
 
 size_t MetaspaceAux::free_chunks_total_words(Metaspace::MetadataType mdtype) {
-  VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
-  if (list == NULL) {
+  ChunkManager* chunk_manager = Metaspace::get_chunk_manager(mdtype);
+  if (chunk_manager == NULL) {
     return 0;
   }
-  ChunkManager* chunk = list->chunk_manager();
-  chunk->slow_verify();
-  return chunk->free_chunks_total_words();
+  chunk_manager->slow_verify();
+  return chunk_manager->free_chunks_total_words();
 }
 
 size_t MetaspaceAux::free_chunks_total_bytes(Metaspace::MetadataType mdtype) {
@@ -2801,9 +2749,9 @@ void MetaspaceAux::dump(outputStream* out) {
 }
 
 void MetaspaceAux::verify_free_chunks() {
-  Metaspace::space_list()->chunk_manager()->verify();
+  Metaspace::chunk_manager_metadata()->verify();
   if (Metaspace::using_class_space()) {
-    Metaspace::class_space_list()->chunk_manager()->verify();
+    Metaspace::chunk_manager_class()->verify();
   }
 }
 
@@ -2874,6 +2822,9 @@ Metaspace::~Metaspace() {
 VirtualSpaceList* Metaspace::_space_list = NULL;
 VirtualSpaceList* Metaspace::_class_space_list = NULL;
 
+ChunkManager* Metaspace::_chunk_manager_metadata = NULL;
+ChunkManager* Metaspace::_chunk_manager_class = NULL;
+
 #define VIRTUALSPACEMULTIPLIER 2
 
 #ifdef _LP64
@@ -2981,6 +2932,7 @@ void Metaspace::initialize_class_space(ReservedSpace rs) {
          err_msg(SIZE_FORMAT " != " UINTX_FORMAT, rs.size(), CompressedClassSpaceSize));
   assert(using_class_space(), "Must be using class space");
   _class_space_list = new VirtualSpaceList(rs);
+  _chunk_manager_class = new ChunkManager(SpecializedChunk, ClassSmallChunk, ClassMediumChunk);
 }
 
 #endif
@@ -3006,6 +2958,7 @@ void Metaspace::global_initialize() {
     // remainder is the misc code and data chunks.
     cds_total = FileMapInfo::shared_spaces_size();
     _space_list = new VirtualSpaceList(cds_total/wordSize);
+    _chunk_manager_metadata = new ChunkManager(SpecializedChunk, SmallChunk, MediumChunk);
 
 #ifdef _LP64
     // Set the compressed klass pointer base so that decoding of these pointers works
@@ -3073,15 +3026,30 @@ void Metaspace::global_initialize() {
     size_t word_size = VIRTUALSPACEMULTIPLIER * first_chunk_word_size();
     // Initialize the list of virtual spaces.
     _space_list = new VirtualSpaceList(word_size);
+    _chunk_manager_metadata = new ChunkManager(SpecializedChunk, SmallChunk, MediumChunk);
   }
 }
 
+Metachunk* Metaspace::get_initialization_chunk(MetadataType mdtype,
+                                               size_t chunk_word_size,
+                                               size_t chunk_bunch) {
+  // Get a chunk from the chunk freelist
+  Metachunk* chunk = get_chunk_manager(mdtype)->chunk_freelist_allocate(chunk_word_size);
+  if (chunk != NULL) {
+    return chunk;
+  }
+
+  return get_space_list(mdtype)->get_initialization_chunk(chunk_word_size, chunk_bunch);
+}
+
 void Metaspace::initialize(Mutex* lock, MetaspaceType type) {
 
   assert(space_list() != NULL,
     "Metadata VirtualSpaceList has not been initialized");
+  assert(chunk_manager_metadata() != NULL,
+    "Metadata ChunkManager has not been initialized");
 
-  _vsm = new SpaceManager(NonClassType, lock, space_list());
+  _vsm = new SpaceManager(NonClassType, lock);
   if (_vsm == NULL) {
     return;
   }
@@ -3090,11 +3058,13 @@ void Metaspace::initialize(Mutex* lock, MetaspaceType type) {
   vsm()->get_initial_chunk_sizes(type, &word_size, &class_word_size);
 
   if (using_class_space()) {
-    assert(class_space_list() != NULL,
-      "Class VirtualSpaceList has not been initialized");
+  assert(class_space_list() != NULL,
+    "Class VirtualSpaceList has not been initialized");
+  assert(chunk_manager_class() != NULL,
+    "Class ChunkManager has not been initialized");
 
     // Allocate SpaceManager for classes.
-    _class_vsm = new SpaceManager(ClassType, lock, class_space_list());
+    _class_vsm = new SpaceManager(ClassType, lock);
     if (_class_vsm == NULL) {
       return;
     }
@@ -3103,9 +3073,9 @@ void Metaspace::initialize(Mutex* lock, MetaspaceType type) {
   MutexLockerEx cl(SpaceManager::expand_lock(), Mutex::_no_safepoint_check_flag);
 
   // Allocate chunk for metadata objects
-  Metachunk* new_chunk =
-     space_list()->get_initialization_chunk(word_size,
-                                            vsm()->medium_chunk_bunch());
+  Metachunk* new_chunk = get_initialization_chunk(NonClassType,
+                                                  word_size,
+                                                  vsm()->medium_chunk_bunch());
   assert(!DumpSharedSpaces || new_chunk != NULL, "should have enough space for both chunks");
   if (new_chunk != NULL) {
     // Add to this manager's list of chunks in use and current_chunk().
@@ -3114,9 +3084,9 @@ void Metaspace::initialize(Mutex* lock, MetaspaceType type) {
 
   // Allocate chunk for class metadata objects
   if (using_class_space()) {
-    Metachunk* class_chunk =
-       class_space_list()->get_initialization_chunk(class_word_size,
-                                                    class_vsm()->medium_chunk_bunch());
+    Metachunk* class_chunk = get_initialization_chunk(ClassType,
+                                                      class_word_size,
+                                                      class_vsm()->medium_chunk_bunch());
     if (class_chunk != NULL) {
       class_vsm()->add_chunk(class_chunk, true);
     }
@@ -3333,12 +3303,16 @@ void Metaspace::iterate(Metaspace::AllocRecordClosure *closure) {
   }
 }
 
+void Metaspace::purge(MetadataType mdtype) {
+  get_space_list(mdtype)->purge(get_chunk_manager(mdtype));
+}
+
 void Metaspace::purge() {
   MutexLockerEx cl(SpaceManager::expand_lock(),
                    Mutex::_no_safepoint_check_flag);
-  space_list()->purge();
+  purge(NonClassType);
   if (using_class_space()) {
-    class_space_list()->purge();
+    purge(ClassType);
   }
 }
 
@@ -3385,7 +3359,7 @@ void Metaspace::dump(outputStream* const out) const {
 
 #ifndef PRODUCT
 
-class MetaspaceAuxTest : AllStatic {
+class TestMetaspaceAuxTest : AllStatic {
  public:
   static void test_reserved() {
     size_t reserved = MetaspaceAux::reserved_bytes();
@@ -3425,14 +3399,25 @@ class MetaspaceAuxTest : AllStatic {
     }
   }
 
+  static void test_virtual_space_list_large_chunk() {
+    VirtualSpaceList* vs_list = new VirtualSpaceList(os::vm_allocation_granularity());
+    MutexLockerEx cl(SpaceManager::expand_lock(), Mutex::_no_safepoint_check_flag);
+    // A size larger than VirtualSpaceSize (256k) and add one page to make it _not_ be
+    // vm_allocation_granularity aligned on Windows.
+    size_t large_size = (size_t)(2*256*K + (os::vm_page_size()/BytesPerWord));
+    large_size += (os::vm_page_size()/BytesPerWord);
+    vs_list->get_new_chunk(large_size, large_size, 0);
+  }
+
   static void test() {
     test_reserved();
     test_committed();
+    test_virtual_space_list_large_chunk();
   }
 };
 
-void MetaspaceAux_test() {
-  MetaspaceAuxTest::test();
+void TestMetaspaceAux_test() {
+  TestMetaspaceAuxTest::test();
 }
 
 #endif
diff --git a/src/share/vm/memory/metaspace.hpp b/src/share/vm/memory/metaspace.hpp
index 242fa61b1cc8dba319cf26874694ae63d8d82939..29c07e1517939ef2e78aac690641ceb9d1e04d01 100644
--- a/src/share/vm/memory/metaspace.hpp
+++ b/src/share/vm/memory/metaspace.hpp
@@ -56,12 +56,15 @@
 //                       +-------------------+
 //
 
+class ChunkManager;
 class ClassLoaderData;
 class Metablock;
+class Metachunk;
 class MetaWord;
 class Mutex;
 class outputStream;
 class SpaceManager;
+class VirtualSpaceList;
 
 // Metaspaces each have a  SpaceManager and allocations
 // are done by the SpaceManager.  Allocations are done
@@ -76,8 +79,6 @@ class SpaceManager;
 // allocate() method returns a block for use as a
 // quantum of metadata.
 
-class VirtualSpaceList;
-
 class Metaspace : public CHeapObj<mtClass> {
   friend class VMStructs;
   friend class SpaceManager;
@@ -102,6 +103,10 @@ class Metaspace : public CHeapObj<mtClass> {
  private:
   void initialize(Mutex* lock, MetaspaceType type);
 
+  Metachunk* get_initialization_chunk(MetadataType mdtype,
+                                      size_t chunk_word_size,
+                                      size_t chunk_bunch);
+
   // Align up the word size to the allocation word size
   static size_t align_word_size_up(size_t);
 
@@ -134,6 +139,10 @@ class Metaspace : public CHeapObj<mtClass> {
   static VirtualSpaceList* _space_list;
   static VirtualSpaceList* _class_space_list;
 
+  static ChunkManager* _chunk_manager_metadata;
+  static ChunkManager* _chunk_manager_class;
+
+ public:
   static VirtualSpaceList* space_list()       { return _space_list; }
   static VirtualSpaceList* class_space_list() { return _class_space_list; }
   static VirtualSpaceList* get_space_list(MetadataType mdtype) {
@@ -141,6 +150,14 @@ class Metaspace : public CHeapObj<mtClass> {
     return mdtype == ClassType ? class_space_list() : space_list();
   }
 
+  static ChunkManager* chunk_manager_metadata() { return _chunk_manager_metadata; }
+  static ChunkManager* chunk_manager_class()    { return _chunk_manager_class; }
+  static ChunkManager* get_chunk_manager(MetadataType mdtype) {
+    assert(mdtype != MetadataTypeCount, "MetadaTypeCount can't be used as mdtype");
+    return mdtype == ClassType ? chunk_manager_class() : chunk_manager_metadata();
+  }
+
+ private:
   // This is used by DumpSharedSpaces only, where only _vsm is used. So we will
   // maintain a single list for now.
   void record_allocation(void* ptr, MetaspaceObj::Type type, size_t word_size);
@@ -199,6 +216,7 @@ class Metaspace : public CHeapObj<mtClass> {
   void dump(outputStream* const out) const;
 
   // Free empty virtualspaces
+  static void purge(MetadataType mdtype);
   static void purge();
 
   void print_on(outputStream* st) const;
diff --git a/src/share/vm/prims/jni.cpp b/src/share/vm/prims/jni.cpp
index c7886920b3e329977d5148c3a3f61ce2b8a4637e..cbd7860a092921f968af6d78b5c79471834c7303 100644
--- a/src/share/vm/prims/jni.cpp
+++ b/src/share/vm/prims/jni.cpp
@@ -5046,7 +5046,10 @@ _JNI_IMPORT_OR_EXPORT_ jint JNICALL JNI_GetDefaultJavaVMInitArgs(void *args_) {
 void TestReservedSpace_test();
 void TestReserveMemorySpecial_test();
 void TestVirtualSpace_test();
-void MetaspaceAux_test();
+void TestMetaspaceAux_test();
+#if INCLUDE_ALL_GCS
+void TestG1BiasedArray_test();
+#endif
 
 void execute_internal_vm_tests() {
   if (ExecuteInternalVMTests) {
@@ -5054,7 +5057,7 @@ void execute_internal_vm_tests() {
     run_unit_test(TestReservedSpace_test());
     run_unit_test(TestReserveMemorySpecial_test());
     run_unit_test(TestVirtualSpace_test());
-    run_unit_test(MetaspaceAux_test());
+    run_unit_test(TestMetaspaceAux_test());
     run_unit_test(GlobalDefinitions::test_globals());
     run_unit_test(GCTimerAllTest::all());
     run_unit_test(arrayOopDesc::test_max_array_length());
@@ -5066,6 +5069,7 @@ void execute_internal_vm_tests() {
     run_unit_test(VMStructs::test());
 #endif
 #if INCLUDE_ALL_GCS
+    run_unit_test(TestG1BiasedArray_test());
     run_unit_test(HeapRegionRemSet::test_prt());
 #endif
     tty->print_cr("All internal VM tests passed");