--- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -50,6 +50,7 @@
 #include "memory/genMarkSweep.hpp"
 #include "memory/genOopClosures.inline.hpp"
 #include "memory/iterator.hpp"
+#include "memory/padded.hpp"
 #include "memory/referencePolicy.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/tenuredGeneration.hpp"

--- a/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -927,11 +927,9 @@
                                    workers->active_workers(),
                                    Threads::number_of_non_daemon_threads());
   workers->set_active_workers(active_workers);
-  _next_gen = gch->next_gen(this);
-  assert(_next_gen != NULL,
-    "This must be the youngest gen, and not the only gen");
   assert(gch->n_gens() == 2,
          "Par collection currently only works with single older gen.");
+  _next_gen = gch->next_gen(this);
   // Do we have to avoid promotion_undo?
   if (gch->collector_policy()->is_concurrent_mark_sweep_policy()) {
     set_avoid_promotion_undo(true);

--- a/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 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
@@ -29,6 +29,7 @@
 #include "gc_implementation/shared/parGCAllocBuffer.hpp"
 #include "gc_implementation/shared/copyFailedInfo.hpp"
 #include "memory/defNewGeneration.hpp"
+#include "memory/padded.hpp"
 #include "utilities/taskqueue.hpp"
 
 class ChunkArray;

--- a/src/share/vm/gc_implementation/parNew/parOopClosures.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parNew/parOopClosures.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 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
@@ -26,6 +26,7 @@
 #define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PAROOPCLOSURES_HPP
 
 #include "memory/genOopClosures.hpp"
+#include "memory/padded.hpp"
 
 // Closures for ParNewGeneration
 

--- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -29,14 +29,16 @@
 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"
 #include "gc_implementation/shared/gcTrace.hpp"
 #include "gc_implementation/shared/mutableSpace.hpp"
+#include "memory/allocation.inline.hpp"
 #include "memory/memRegion.hpp"
+#include "memory/padded.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "oops/oop.psgc.inline.hpp"
 
-PSPromotionManager**         PSPromotionManager::_manager_array = NULL;
-OopStarTaskQueueSet*         PSPromotionManager::_stack_array_depth = NULL;
-PSOldGen*                    PSPromotionManager::_old_gen = NULL;
-MutableSpace*                PSPromotionManager::_young_space = NULL;
+PaddedEnd<PSPromotionManager>* PSPromotionManager::_manager_array = NULL;
+OopStarTaskQueueSet*           PSPromotionManager::_stack_array_depth = NULL;
+PSOldGen*                      PSPromotionManager::_old_gen = NULL;
+MutableSpace*                  PSPromotionManager::_young_space = NULL;
 
 void PSPromotionManager::initialize() {
   ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
@@ -45,8 +47,10 @@
   _old_gen = heap->old_gen();
   _young_space = heap->young_gen()->to_space();
 
+  // To prevent false sharing, we pad the PSPromotionManagers
+  // and make sure that the first instance starts at a cache line.
   assert(_manager_array == NULL, "Attempt to initialize twice");
-  _manager_array = NEW_C_HEAP_ARRAY(PSPromotionManager*, ParallelGCThreads+1, mtGC);
+  _manager_array = PaddedArray<PSPromotionManager, mtGC>::create_unfreeable(ParallelGCThreads + 1);
   guarantee(_manager_array != NULL, "Could not initialize promotion manager");
 
   _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);
@@ -54,26 +58,21 @@
 
   // Create and register the PSPromotionManager(s) for the worker threads.
   for(uint i=0; i<ParallelGCThreads; i++) {
-    _manager_array[i] = new PSPromotionManager();
-    guarantee(_manager_array[i] != NULL, "Could not create PSPromotionManager");
-    stack_array_depth()->register_queue(i, _manager_array[i]->claimed_stack_depth());
+    stack_array_depth()->register_queue(i, _manager_array[i].claimed_stack_depth());
   }
-
   // The VMThread gets its own PSPromotionManager, which is not available
   // for work stealing.
-  _manager_array[ParallelGCThreads] = new PSPromotionManager();
-  guarantee(_manager_array[ParallelGCThreads] != NULL, "Could not create PSPromotionManager");
 }
 
 PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(int index) {
   assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");
   assert(_manager_array != NULL, "Sanity");
-  return _manager_array[index];
+  return &_manager_array[index];
 }
 
 PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {
   assert(_manager_array != NULL, "Sanity");
-  return _manager_array[ParallelGCThreads];
+  return &_manager_array[ParallelGCThreads];
 }
 
 void PSPromotionManager::pre_scavenge() {

--- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -29,6 +29,8 @@
 #include "gc_implementation/shared/gcTrace.hpp"
 #include "gc_implementation/shared/copyFailedInfo.hpp"
 #include "memory/allocation.hpp"
+#include "memory/padded.hpp"
+#include "utilities/globalDefinitions.hpp"
 #include "utilities/taskqueue.hpp"
 
 //
@@ -51,14 +53,14 @@
 class PSOldGen;
 class ParCompactionManager;
 
-class PSPromotionManager : public CHeapObj<mtGC> {
+class PSPromotionManager VALUE_OBJ_CLASS_SPEC {
   friend class PSScavenge;
   friend class PSRefProcTaskExecutor;
  private:
-  static PSPromotionManager**         _manager_array;
-  static OopStarTaskQueueSet*         _stack_array_depth;
-  static PSOldGen*                    _old_gen;
-  static MutableSpace*                _young_space;
+  static PaddedEnd<PSPromotionManager>* _manager_array;
+  static OopStarTaskQueueSet*           _stack_array_depth;
+  static PSOldGen*                      _old_gen;
+  static MutableSpace*                  _young_space;
 
 #if TASKQUEUE_STATS
   size_t                              _masked_pushes;

--- a/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -32,7 +32,7 @@
 inline PSPromotionManager* PSPromotionManager::manager_array(int index) {
   assert(_manager_array != NULL, "access of NULL manager_array");
   assert(index >= 0 && index <= (int)ParallelGCThreads, "out of range manager_array access");
-  return _manager_array[index];
+  return &_manager_array[index];
 }
 
 template <class T>

--- a/src/share/vm/gc_implementation/shared/objectCountEventSender.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/gc_implementation/shared/objectCountEventSender.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -32,6 +32,7 @@
 #if INCLUDE_SERVICES
 
 void ObjectCountEventSender::send(const KlassInfoEntry* entry, GCId gc_id, jlong timestamp) {
+#if INCLUDE_TRACE
   assert(Tracing::is_event_enabled(EventObjectCountAfterGC::eventId),
          "Only call this method if the event is enabled");
 
@@ -42,6 +43,7 @@
   event.set_totalSize(entry->words() * BytesPerWord);
   event.set_endtime(timestamp);
   event.commit();
+#endif // INCLUDE_TRACE
 }
 
 bool ObjectCountEventSender::should_send_event() {

--- a/src/share/vm/memory/cardTableRS.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/cardTableRS.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -310,46 +310,31 @@
   _ct_bs->non_clean_card_iterate_possibly_parallel(sp, urasm, cl, this);
 }
 
-void CardTableRS::clear_into_younger(Generation* gen) {
-  GenCollectedHeap* gch = GenCollectedHeap::heap();
-  // Generations younger than gen have been evacuated. We can clear
-  // card table entries for gen (we know that it has no pointers
-  // to younger gens) and for those below. The card tables for
-  // the youngest gen need never be cleared.
+void CardTableRS::clear_into_younger(Generation* old_gen) {
+  assert(old_gen->level() == 1, "Should only be called for the old generation");
+  // The card tables for the youngest gen need never be cleared.
   // There's a bit of subtlety in the clear() and invalidate()
   // methods that we exploit here and in invalidate_or_clear()
   // below to avoid missing cards at the fringes. If clear() or
   // invalidate() are changed in the future, this code should
   // be revisited. 20040107.ysr
-  Generation* g = gen;
-  for(Generation* prev_gen = gch->prev_gen(g);
-      prev_gen != NULL;
-      g = prev_gen, prev_gen = gch->prev_gen(g)) {
-    MemRegion to_be_cleared_mr = g->prev_used_region();
-    clear(to_be_cleared_mr);
-  }
+  clear(old_gen->prev_used_region());
 }
 
-void CardTableRS::invalidate_or_clear(Generation* gen, bool younger) {
-  GenCollectedHeap* gch = GenCollectedHeap::heap();
-  // For each generation gen (and younger)
-  // invalidate the cards for the currently occupied part
-  // of that generation and clear the cards for the
+void CardTableRS::invalidate_or_clear(Generation* old_gen) {
+  assert(old_gen->level() == 1, "Should only be called for the old generation");
+  // Invalidate the cards for the currently occupied part of
+  // the old generation and clear the cards for the
   // unoccupied part of the generation (if any, making use
   // of that generation's prev_used_region to determine that
   // region). No need to do anything for the youngest
   // generation. Also see note#20040107.ysr above.
-  Generation* g = gen;
-  for(Generation* prev_gen = gch->prev_gen(g); prev_gen != NULL;
-      g = prev_gen, prev_gen = gch->prev_gen(g))  {
-    MemRegion used_mr = g->used_region();
-    MemRegion to_be_cleared_mr = g->prev_used_region().minus(used_mr);
-    if (!to_be_cleared_mr.is_empty()) {
-      clear(to_be_cleared_mr);
-    }
-    invalidate(used_mr);
-    if (!younger) break;
+  MemRegion used_mr = old_gen->used_region();
+  MemRegion to_be_cleared_mr = old_gen->prev_used_region().minus(used_mr);
+  if (!to_be_cleared_mr.is_empty()) {
+    clear(to_be_cleared_mr);
   }
+  invalidate(used_mr);
 }
 
 

--- a/src/share/vm/memory/cardTableRS.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/cardTableRS.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -142,12 +142,12 @@
   void verify_aligned_region_empty(MemRegion mr);
 
   void clear(MemRegion mr) { _ct_bs->clear(mr); }
-  void clear_into_younger(Generation* gen);
+  void clear_into_younger(Generation* old_gen);
 
   void invalidate(MemRegion mr, bool whole_heap = false) {
     _ct_bs->invalidate(mr, whole_heap);
   }
-  void invalidate_or_clear(Generation* gen, bool younger);
+  void invalidate_or_clear(Generation* old_gen);
 
   static uintx ct_max_alignment_constraint() {
     return CardTableModRefBS::ct_max_alignment_constraint();

--- a/src/share/vm/memory/defNewGeneration.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/defNewGeneration.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -567,8 +567,6 @@
   gc_tracer.report_gc_start(gch->gc_cause(), _gc_timer->gc_start());
 
   _next_gen = gch->next_gen(this);
-  assert(_next_gen != NULL,
-    "This must be the youngest gen, and not the only gen");
 
   // If the next generation is too full to accommodate promotion
   // from this generation, pass on collection; let the next generation
@@ -901,8 +899,6 @@
   if (_next_gen == NULL) {
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     _next_gen = gch->next_gen(this);
-    assert(_next_gen != NULL,
-           "This must be the youngest gen, and not the only gen");
   }
   return _next_gen->promotion_attempt_is_safe(used());
 }

--- a/src/share/vm/memory/genCollectedHeap.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/genCollectedHeap.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -1070,13 +1070,13 @@
 
 
 void GenCollectedHeap::prepare_for_compaction() {
-  Generation* scanning_gen = _gens[_n_gens-1];
+  guarantee(_n_gens = 2, "Wrong number of generations");
+  Generation* old_gen = _gens[1];
   // Start by compacting into same gen.
-  CompactPoint cp(scanning_gen, NULL, NULL);
-  while (scanning_gen != NULL) {
-    scanning_gen->prepare_for_compaction(&cp);
-    scanning_gen = prev_gen(scanning_gen);
-  }
+  CompactPoint cp(old_gen, NULL, NULL);
+  old_gen->prepare_for_compaction(&cp);
+  Generation* young_gen = _gens[0];
+  young_gen->prepare_for_compaction(&cp);
 }
 
 GCStats* GenCollectedHeap::gc_stats(int level) const {
@@ -1245,27 +1245,14 @@
   generation_iterate(&ep_cl, false);
 }
 
-oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
+oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen,
                                               oop obj,
                                               size_t obj_size) {
+  guarantee(old_gen->level() == 1, "We only get here with an old generation");
   assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
   HeapWord* result = NULL;
 
-  // First give each higher generation a chance to allocate the promoted object.
-  Generation* allocator = next_gen(gen);
-  if (allocator != NULL) {
-    do {
-      result = allocator->allocate(obj_size, false);
-    } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
-  }
-
-  if (result == NULL) {
-    // Then give gen and higher generations a chance to expand and allocate the
-    // object.
-    do {
-      result = gen->expand_and_allocate(obj_size, false);
-    } while (result == NULL && (gen = next_gen(gen)) != NULL);
-  }
+  result = old_gen->expand_and_allocate(obj_size, false);
 
   if (result != NULL) {
     Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);

--- a/src/share/vm/memory/genCollectedHeap.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/genCollectedHeap.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -368,25 +368,23 @@
   // collection.
   virtual bool is_maximal_no_gc() const;
 
-  // Return the generation before "gen", or else NULL.
+  // Return the generation before "gen".
   Generation* prev_gen(Generation* gen) const {
     int l = gen->level();
-    if (l == 0) return NULL;
-    else return _gens[l-1];
+    guarantee(l > 0, "Out of bounds");
+    return _gens[l-1];
   }
 
-  // Return the generation after "gen", or else NULL.
+  // Return the generation after "gen".
   Generation* next_gen(Generation* gen) const {
     int l = gen->level() + 1;
-    if (l == _n_gens) return NULL;
-    else return _gens[l];
+    guarantee(l < _n_gens, "Out of bounds");
+    return _gens[l];
   }
 
   Generation* get_gen(int i) const {
-    if (i >= 0 && i < _n_gens)
-      return _gens[i];
-    else
-      return NULL;
+    guarantee(i >= 0 && i < _n_gens, "Out of bounds");
+    return _gens[i];
   }
 
   int n_gens() const {
@@ -485,9 +483,9 @@
 
   // Promotion of obj into gen failed.  Try to promote obj to higher
   // gens in ascending order; return the new location of obj if successful.
-  // Otherwise, try expand-and-allocate for obj in each generation starting at
-  // gen; return the new location of obj if successful.  Otherwise, return NULL.
-  oop handle_failed_promotion(Generation* gen,
+  // Otherwise, try expand-and-allocate for obj in both the young and old
+  // generation; return the new location of obj if successful.  Otherwise, return NULL.
+  oop handle_failed_promotion(Generation* old_gen,
                               oop obj,
                               size_t obj_size);
 

--- a/src/share/vm/memory/genMarkSweep.cpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/genMarkSweep.cpp	Fri Aug 16 09:02:36 2013 +0200
@@ -52,8 +52,8 @@
 #include "utilities/copy.hpp"
 #include "utilities/events.hpp"
 
-void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp,
-  bool clear_all_softrefs) {
+void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, bool clear_all_softrefs) {
+  guarantee(level == 1, "We always collect both old and young.");
   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
 
   GenCollectedHeap* gch = GenCollectedHeap::heap();
@@ -84,11 +84,6 @@
   // Capture heap size before collection for printing.
   size_t gch_prev_used = gch->used();
 
-  // Some of the card table updates below assume that the perm gen is
-  // also being collected.
-  assert(level == gch->n_gens() - 1,
-         "All generations are being collected, ergo perm gen too.");
-
   // Capture used regions for each generation that will be
   // subject to collection, so that card table adjustments can
   // be made intelligently (see clear / invalidate further below).
@@ -126,17 +121,15 @@
     all_empty = all_empty && gch->get_gen(i)->used() == 0;
   }
   GenRemSet* rs = gch->rem_set();
+  Generation* old_gen = gch->get_gen(level);
   // Clear/invalidate below make use of the "prev_used_regions" saved earlier.
   if (all_empty) {
     // We've evacuated all generations below us.
-    Generation* g = gch->get_gen(level);
-    rs->clear_into_younger(g);
+    rs->clear_into_younger(old_gen);
   } else {
     // Invalidate the cards corresponding to the currently used
-    // region and clear those corresponding to the evacuated region
-    // of all generations just collected (i.e. level and younger).
-    rs->invalidate_or_clear(gch->get_gen(level),
-                            true /* younger */);
+    // region and clear those corresponding to the evacuated region.
+    rs->invalidate_or_clear(old_gen);
   }
 
   Threads::gc_epilogue();

--- a/src/share/vm/memory/genRemSet.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/memory/genRemSet.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -135,7 +135,7 @@
   // younger than gen from generations gen and older.
   // The parameter clear_perm indicates if the perm_gen's
   // remembered set should also be processed/cleared.
-  virtual void clear_into_younger(Generation* gen) = 0;
+  virtual void clear_into_younger(Generation* old_gen) = 0;
 
   // Informs the RS that refs in the given "mr" may have changed
   // arbitrarily, and therefore may contain old-to-young pointers.
@@ -146,11 +146,8 @@
 
   // Informs the RS that refs in this generation
   // may have changed arbitrarily, and therefore may contain
-  // old-to-young pointers in arbitrary locations. The parameter
-  // younger indicates if the same should be done for younger generations
-  // as well. The parameter perm indicates if the same should be done for
-  // perm gen as well.
-  virtual void invalidate_or_clear(Generation* gen, bool younger) = 0;
+  // old-to-young pointers in arbitrary locations.
+  virtual void invalidate_or_clear(Generation* old_gen) = 0;
 };
 
 #endif // SHARE_VM_MEMORY_GENREMSET_HPP

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/memory/padded.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -0,0 +1,93 @@
+/*
+ * 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_MEMORY_PADDED_HPP
+#define SHARE_VM_MEMORY_PADDED_HPP
+
+#include "memory/allocation.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// Bytes needed to pad type to avoid cache-line sharing; alignment should be the
+// expected cache line size (a power of two).  The first addend avoids sharing
+// when the start address is not a multiple of alignment; the second maintains
+// alignment of starting addresses that happen to be a multiple.
+#define PADDING_SIZE(type, alignment)                           \
+  ((alignment) + align_size_up_(sizeof(type), alignment))
+
+// Templates to create a subclass padded to avoid cache line sharing.  These are
+// effective only when applied to derived-most (leaf) classes.
+
+// When no args are passed to the base ctor.
+template <class T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
+class Padded : public T {
+ private:
+  char _pad_buf_[PADDING_SIZE(T, alignment)];
+};
+
+// When either 0 or 1 args may be passed to the base ctor.
+template <class T, typename Arg1T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
+class Padded01 : public T {
+ public:
+  Padded01(): T() { }
+  Padded01(Arg1T arg1): T(arg1) { }
+ private:
+  char _pad_buf_[PADDING_SIZE(T, alignment)];
+};
+
+// Super class of PaddedEnd when pad_size != 0.
+template <class T, size_t pad_size>
+class PaddedEndImpl : public T {
+ private:
+  char _pad_buf[pad_size];
+};
+
+// Super class of PaddedEnd when pad_size == 0.
+template <class T>
+class PaddedEndImpl<T, /*pad_size*/ 0> : public T {
+  // No padding.
+};
+
+#define PADDED_END_SIZE(type, alignment) (align_size_up_(sizeof(type), alignment) - sizeof(type))
+
+// More memory conservative implementation of Padded. The subclass adds the
+// minimal amount of padding needed to make the size of the objects be aligned.
+// This will help reducing false sharing,
+// if the start address is a multiple of alignment.
+template <class T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
+class PaddedEnd : public PaddedEndImpl<T, PADDED_END_SIZE(T, alignment)> {
+  // C++ don't allow zero-length arrays. The padding is put in a
+  // super class that is specialized for the pad_size == 0 case.
+};
+
+// Helper class to create an array of PaddedEnd<T> objects. All elements will
+// start at a multiple of alignment and the size will be aligned to alignment.
+template <class T, MEMFLAGS flags, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
+class PaddedArray {
+ public:
+  // Creates an aligned padded array.
+  // The memory can't be deleted since the raw memory chunk is not returned.
+  static PaddedEnd<T>* create_unfreeable(uint length);
+};
+
+#endif // SHARE_VM_MEMORY_PADDED_HPP

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/memory/padded.inline.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -0,0 +1,49 @@
+/*
+ * 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 "memory/allocation.inline.hpp"
+#include "memory/padded.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// Creates an aligned padded array.
+// The memory can't be deleted since the raw memory chunk is not returned.
+template <class T, MEMFLAGS flags, size_t alignment>
+PaddedEnd<T>* PaddedArray<T, flags, alignment>::create_unfreeable(uint length) {
+  // Check that the PaddedEnd class works as intended.
+  STATIC_ASSERT(is_size_aligned_(sizeof(PaddedEnd<T>), alignment));
+
+  // Allocate a chunk of memory large enough to allow for some alignment.
+  void* chunk = AllocateHeap(length * sizeof(PaddedEnd<T, alignment>) + alignment, flags);
+
+  // Make the initial alignment.
+  PaddedEnd<T>* aligned_padded_array = (PaddedEnd<T>*)align_pointer_up(chunk, alignment);
+
+  // Call the default constructor for each element.
+  for (uint i = 0; i < length; i++) {
+    ::new (&aligned_padded_array[i]) T();
+  }
+
+  return aligned_padded_array;
+}

--- a/src/share/vm/utilities/debug.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/utilities/debug.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -225,6 +225,22 @@
 
 void warning(const char* format, ...);
 
+#ifdef ASSERT
+// Compile-time asserts.
+template <bool> struct StaticAssert;
+template <> struct StaticAssert<true> {};
+
+// Only StaticAssert<true> is defined, so if cond evaluates to false we get
+// a compile time exception when trying to use StaticAssert<false>.
+#define STATIC_ASSERT(cond)                   \
+  do {                                        \
+    StaticAssert<(cond)> DUMMY_STATIC_ASSERT; \
+    (void)DUMMY_STATIC_ASSERT; /* ignore */   \
+  } while (false)
+#else
+#define STATIC_ASSERT(cond)
+#endif
+
 // out of shared space reporting
 enum SharedSpaceType {
   SharedPermGen,

--- a/src/share/vm/utilities/exceptions.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/utilities/exceptions.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -306,6 +306,6 @@
 // which preserves pre-existing exceptions and does not allow new
 // exceptions.
 
-#define EXCEPTION_MARK                           Thread* THREAD; ExceptionMark __em(THREAD);
+#define EXCEPTION_MARK                           Thread* THREAD = NULL; ExceptionMark __em(THREAD);
 
 #endif // SHARE_VM_UTILITIES_EXCEPTIONS_HPP

--- a/src/share/vm/utilities/globalDefinitions.hpp	Thu Aug 15 15:26:16 2013 +0200
+++ b/src/share/vm/utilities/globalDefinitions.hpp	Fri Aug 16 09:02:36 2013 +0200
@@ -410,6 +410,8 @@
   return align_size_down_(size, alignment);
 }
 
+#define is_size_aligned_(size, alignment) ((size) == (align_size_up_(size, alignment)))
+
 // Align objects by rounding up their size, in HeapWord units.
 
 #define align_object_size_(size) align_size_up_(size, MinObjAlignment)
@@ -428,6 +430,10 @@
   return align_size_up(offset, HeapWordsPerLong);
 }
 
+inline void* align_pointer_up(const void* addr, size_t size) {
+  return (void*) align_size_up_((uintptr_t)addr, size);
+}
+
 // Clamp an address to be within a specific page
 // 1. If addr is on the page it is returned as is
 // 2. If addr is above the page_address the start of the *next* page will be returned
@@ -449,32 +455,6 @@
 // The expected size in bytes of a cache line, used to pad data structures.
 #define DEFAULT_CACHE_LINE_SIZE 64
 
-// Bytes needed to pad type to avoid cache-line sharing; alignment should be the
-// expected cache line size (a power of two).  The first addend avoids sharing
-// when the start address is not a multiple of alignment; the second maintains
-// alignment of starting addresses that happen to be a multiple.
-#define PADDING_SIZE(type, alignment)                           \
-  ((alignment) + align_size_up_(sizeof(type), alignment))
-
-// Templates to create a subclass padded to avoid cache line sharing.  These are
-// effective only when applied to derived-most (leaf) classes.
-
-// When no args are passed to the base ctor.
-template <class T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
-class Padded: public T {
-private:
-  char _pad_buf_[PADDING_SIZE(T, alignment)];
-};
-
-// When either 0 or 1 args may be passed to the base ctor.
-template <class T, typename Arg1T, size_t alignment = DEFAULT_CACHE_LINE_SIZE>
-class Padded01: public T {
-public:
-  Padded01(): T() { }
-  Padded01(Arg1T arg1): T(arg1) { }
-private:
-  char _pad_buf_[PADDING_SIZE(T, alignment)];
-};
 
 //----------------------------------------------------------------------------------------------------
 // Utility macros for compilers