--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,2845 @@
+/*
+ * Copyright 2001-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_compactibleFreeListSpace.cpp.incl"
+
+/////////////////////////////////////////////////////////////////////////
+//// CompactibleFreeListSpace
+/////////////////////////////////////////////////////////////////////////
+
+// highest ranked  free list lock rank
+int CompactibleFreeListSpace::_lockRank = Mutex::leaf + 3;
+
+// Constructor
+CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs,
+  MemRegion mr, bool use_adaptive_freelists,
+  FreeBlockDictionary::DictionaryChoice dictionaryChoice) :
+  _dictionaryChoice(dictionaryChoice),
+  _adaptive_freelists(use_adaptive_freelists),
+  _bt(bs, mr),
+  // free list locks are in the range of values taken by _lockRank
+  // This range currently is [_leaf+2, _leaf+3]
+  // Note: this requires that CFLspace c'tors
+  // are called serially in the order in which the locks are
+  // are acquired in the program text. This is true today.
+  _freelistLock(_lockRank--, "CompactibleFreeListSpace._lock", true),
+  _parDictionaryAllocLock(Mutex::leaf - 1,  // == rank(ExpandHeap_lock) - 1
+                          "CompactibleFreeListSpace._dict_par_lock", true),
+  _rescan_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord *
+                    CMSRescanMultiple),
+  _marking_task_size(CardTableModRefBS::card_size_in_words * BitsPerWord *
+                    CMSConcMarkMultiple),
+  _collector(NULL)
+{
+  _bt.set_space(this);
+  initialize(mr, true);
+  // We have all of "mr", all of which we place in the dictionary
+  // as one big chunk. We'll need to decide here which of several
+  // possible alternative dictionary implementations to use. For
+  // now the choice is easy, since we have only one working
+  // implementation, namely, the simple binary tree (splaying
+  // temporarily disabled).
+  switch (dictionaryChoice) {
+    case FreeBlockDictionary::dictionaryBinaryTree:
+      _dictionary = new BinaryTreeDictionary(mr);
+      break;
+    case FreeBlockDictionary::dictionarySplayTree:
+    case FreeBlockDictionary::dictionarySkipList:
+    default:
+      warning("dictionaryChoice: selected option not understood; using"
+              " default BinaryTreeDictionary implementation instead.");
+      _dictionary = new BinaryTreeDictionary(mr);
+      break;
+  }
+  splitBirth(mr.word_size());
+  assert(_dictionary != NULL, "CMS dictionary initialization");
+  // The indexed free lists are initially all empty and are lazily
+  // filled in on demand. Initialize the array elements to NULL.
+  initializeIndexedFreeListArray();
+
+  // Not using adaptive free lists assumes that allocation is first
+  // from the linAB's.  Also a cms perm gen which can be compacted
+  // has to have the klass's klassKlass allocated at a lower
+  // address in the heap than the klass so that the klassKlass is
+  // moved to its new location before the klass is moved.
+  // Set the _refillSize for the linear allocation blocks
+  if (!use_adaptive_freelists) {
+    FreeChunk* fc = _dictionary->getChunk(mr.word_size());
+    // The small linAB initially has all the space and will allocate
+    // a chunk of any size.
+    HeapWord* addr = (HeapWord*) fc;
+    _smallLinearAllocBlock.set(addr, fc->size() ,
+      1024*SmallForLinearAlloc, fc->size());
+    // Note that _unallocated_block is not updated here.
+    // Allocations from the linear allocation block should
+    // update it.
+  } else {
+    _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc,
+                               SmallForLinearAlloc);
+  }
+  // CMSIndexedFreeListReplenish should be at least 1
+  CMSIndexedFreeListReplenish = MAX2((uintx)1, CMSIndexedFreeListReplenish);
+  _promoInfo.setSpace(this);
+  if (UseCMSBestFit) {
+    _fitStrategy = FreeBlockBestFitFirst;
+  } else {
+    _fitStrategy = FreeBlockStrategyNone;
+  }
+  checkFreeListConsistency();
+
+  // Initialize locks for parallel case.
+  if (ParallelGCThreads > 0) {
+    for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+      _indexedFreeListParLocks[i] = new Mutex(Mutex::leaf - 1, // == ExpandHeap_lock - 1
+                                              "a freelist par lock",
+                                              true);
+      if (_indexedFreeListParLocks[i] == NULL)
+        vm_exit_during_initialization("Could not allocate a par lock");
+      DEBUG_ONLY(
+        _indexedFreeList[i].set_protecting_lock(_indexedFreeListParLocks[i]);
+      )
+    }
+    _dictionary->set_par_lock(&_parDictionaryAllocLock);
+  }
+}
+
+// Like CompactibleSpace forward() but always calls cross_threshold() to
+// update the block offset table.  Removed initialize_threshold call because
+// CFLS does not use a block offset array for contiguous spaces.
+HeapWord* CompactibleFreeListSpace::forward(oop q, size_t size,
+                                    CompactPoint* cp, HeapWord* compact_top) {
+  // q is alive
+  // First check if we should switch compaction space
+  assert(this == cp->space, "'this' should be current compaction space.");
+  size_t compaction_max_size = pointer_delta(end(), compact_top);
+  assert(adjustObjectSize(size) == cp->space->adjust_object_size_v(size),
+    "virtual adjustObjectSize_v() method is not correct");
+  size_t adjusted_size = adjustObjectSize(size);
+  assert(compaction_max_size >= MinChunkSize || compaction_max_size == 0,
+         "no small fragments allowed");
+  assert(minimum_free_block_size() == MinChunkSize,
+         "for de-virtualized reference below");
+  // Can't leave a nonzero size, residual fragment smaller than MinChunkSize
+  if (adjusted_size + MinChunkSize > compaction_max_size &&
+      adjusted_size != compaction_max_size) {
+    do {
+      // switch to next compaction space
+      cp->space->set_compaction_top(compact_top);
+      cp->space = cp->space->next_compaction_space();
+      if (cp->space == NULL) {
+        cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen);
+        assert(cp->gen != NULL, "compaction must succeed");
+        cp->space = cp->gen->first_compaction_space();
+        assert(cp->space != NULL, "generation must have a first compaction space");
+      }
+      compact_top = cp->space->bottom();
+      cp->space->set_compaction_top(compact_top);
+      // The correct adjusted_size may not be the same as that for this method
+      // (i.e., cp->space may no longer be "this" so adjust the size again.
+      // Use the virtual method which is not used above to save the virtual
+      // dispatch.
+      adjusted_size = cp->space->adjust_object_size_v(size);
+      compaction_max_size = pointer_delta(cp->space->end(), compact_top);
+      assert(cp->space->minimum_free_block_size() == 0, "just checking");
+    } while (adjusted_size > compaction_max_size);
+  }
+
+  // store the forwarding pointer into the mark word
+  if ((HeapWord*)q != compact_top) {
+    q->forward_to(oop(compact_top));
+    assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
+  } else {
+    // if the object isn't moving we can just set the mark to the default
+    // mark and handle it specially later on.
+    q->init_mark();
+    assert(q->forwardee() == NULL, "should be forwarded to NULL");
+  }
+
+  debug_only(MarkSweep::register_live_oop(q, adjusted_size));
+  compact_top += adjusted_size;
+
+  // we need to update the offset table so that the beginnings of objects can be
+  // found during scavenge.  Note that we are updating the offset table based on
+  // where the object will be once the compaction phase finishes.
+
+  // Always call cross_threshold().  A contiguous space can only call it when
+  // the compaction_top exceeds the current threshold but not for an
+  // non-contiguous space.
+  cp->threshold =
+    cp->space->cross_threshold(compact_top - adjusted_size, compact_top);
+  return compact_top;
+}
+
+// A modified copy of OffsetTableContigSpace::cross_threshold() with _offsets -> _bt
+// and use of single_block instead of alloc_block.  The name here is not really
+// appropriate - maybe a more general name could be invented for both the
+// contiguous and noncontiguous spaces.
+
+HeapWord* CompactibleFreeListSpace::cross_threshold(HeapWord* start, HeapWord* the_end) {
+  _bt.single_block(start, the_end);
+  return end();
+}
+
+// Initialize them to NULL.
+void CompactibleFreeListSpace::initializeIndexedFreeListArray() {
+  for (size_t i = 0; i < IndexSetSize; i++) {
+    // Note that on platforms where objects are double word aligned,
+    // the odd array elements are not used.  It is convenient, however,
+    // to map directly from the object size to the array element.
+    _indexedFreeList[i].reset(IndexSetSize);
+    _indexedFreeList[i].set_size(i);
+    assert(_indexedFreeList[i].count() == 0, "reset check failed");
+    assert(_indexedFreeList[i].head() == NULL, "reset check failed");
+    assert(_indexedFreeList[i].tail() == NULL, "reset check failed");
+    assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed");
+  }
+}
+
+void CompactibleFreeListSpace::resetIndexedFreeListArray() {
+  for (int i = 1; i < IndexSetSize; i++) {
+    assert(_indexedFreeList[i].size() == (size_t) i,
+      "Indexed free list sizes are incorrect");
+    _indexedFreeList[i].reset(IndexSetSize);
+    assert(_indexedFreeList[i].count() == 0, "reset check failed");
+    assert(_indexedFreeList[i].head() == NULL, "reset check failed");
+    assert(_indexedFreeList[i].tail() == NULL, "reset check failed");
+    assert(_indexedFreeList[i].hint() == IndexSetSize, "reset check failed");
+  }
+}
+
+void CompactibleFreeListSpace::reset(MemRegion mr) {
+  resetIndexedFreeListArray();
+  dictionary()->reset();
+  if (BlockOffsetArrayUseUnallocatedBlock) {
+    assert(end() == mr.end(), "We are compacting to the bottom of CMS gen");
+    // Everything's allocated until proven otherwise.
+    _bt.set_unallocated_block(end());
+  }
+  if (!mr.is_empty()) {
+    assert(mr.word_size() >= MinChunkSize, "Chunk size is too small");
+    _bt.single_block(mr.start(), mr.word_size());
+    FreeChunk* fc = (FreeChunk*) mr.start();
+    fc->setSize(mr.word_size());
+    if (mr.word_size() >= IndexSetSize ) {
+      returnChunkToDictionary(fc);
+    } else {
+      _bt.verify_not_unallocated((HeapWord*)fc, fc->size());
+      _indexedFreeList[mr.word_size()].returnChunkAtHead(fc);
+    }
+  }
+  _promoInfo.reset();
+  _smallLinearAllocBlock._ptr = NULL;
+  _smallLinearAllocBlock._word_size = 0;
+}
+
+void CompactibleFreeListSpace::reset_after_compaction() {
+  // Reset the space to the new reality - one free chunk.
+  MemRegion mr(compaction_top(), end());
+  reset(mr);
+  // Now refill the linear allocation block(s) if possible.
+  if (_adaptive_freelists) {
+    refillLinearAllocBlocksIfNeeded();
+  } else {
+    // Place as much of mr in the linAB as we can get,
+    // provided it was big enough to go into the dictionary.
+    FreeChunk* fc = dictionary()->findLargestDict();
+    if (fc != NULL) {
+      assert(fc->size() == mr.word_size(),
+             "Why was the chunk broken up?");
+      removeChunkFromDictionary(fc);
+      HeapWord* addr = (HeapWord*) fc;
+      _smallLinearAllocBlock.set(addr, fc->size() ,
+        1024*SmallForLinearAlloc, fc->size());
+      // Note that _unallocated_block is not updated here.
+    }
+  }
+}
+
+// Walks the entire dictionary, returning a coterminal
+// chunk, if it exists. Use with caution since it involves
+// a potentially complete walk of a potentially large tree.
+FreeChunk* CompactibleFreeListSpace::find_chunk_at_end() {
+
+  assert_lock_strong(&_freelistLock);
+
+  return dictionary()->find_chunk_ends_at(end());
+}
+
+
+#ifndef PRODUCT
+void CompactibleFreeListSpace::initializeIndexedFreeListArrayReturnedBytes() {
+  for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    _indexedFreeList[i].allocation_stats()->set_returnedBytes(0);
+  }
+}
+
+size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() {
+  size_t sum = 0;
+  for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    sum += _indexedFreeList[i].allocation_stats()->returnedBytes();
+  }
+  return sum;
+}
+
+size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const {
+  size_t count = 0;
+  for (int i = MinChunkSize; i < IndexSetSize; i++) {
+    debug_only(
+      ssize_t total_list_count = 0;
+      for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;
+         fc = fc->next()) {
+        total_list_count++;
+      }
+      assert(total_list_count ==  _indexedFreeList[i].count(),
+        "Count in list is incorrect");
+    )
+    count += _indexedFreeList[i].count();
+  }
+  return count;
+}
+
+size_t CompactibleFreeListSpace::totalCount() {
+  size_t num = totalCountInIndexedFreeLists();
+  num +=  dictionary()->totalCount();
+  if (_smallLinearAllocBlock._word_size != 0) {
+    num++;
+  }
+  return num;
+}
+#endif
+
+bool CompactibleFreeListSpace::is_free_block(const HeapWord* p) const {
+  FreeChunk* fc = (FreeChunk*) p;
+  return fc->isFree();
+}
+
+size_t CompactibleFreeListSpace::used() const {
+  return capacity() - free();
+}
+
+size_t CompactibleFreeListSpace::free() const {
+  // "MT-safe, but not MT-precise"(TM), if you will: i.e.
+  // if you do this while the structures are in flux you
+  // may get an approximate answer only; for instance
+  // because there is concurrent allocation either
+  // directly by mutators or for promotion during a GC.
+  // It's "MT-safe", however, in the sense that you are guaranteed
+  // not to crash and burn, for instance, because of walking
+  // pointers that could disappear as you were walking them.
+  // The approximation is because the various components
+  // that are read below are not read atomically (and
+  // further the computation of totalSizeInIndexedFreeLists()
+  // is itself a non-atomic computation. The normal use of
+  // this is during a resize operation at the end of GC
+  // and at that time you are guaranteed to get the
+  // correct actual value. However, for instance, this is
+  // also read completely asynchronously by the "perf-sampler"
+  // that supports jvmstat, and you are apt to see the values
+  // flicker in such cases.
+  assert(_dictionary != NULL, "No _dictionary?");
+  return (_dictionary->totalChunkSize(DEBUG_ONLY(freelistLock())) +
+          totalSizeInIndexedFreeLists() +
+          _smallLinearAllocBlock._word_size) * HeapWordSize;
+}
+
+size_t CompactibleFreeListSpace::max_alloc_in_words() const {
+  assert(_dictionary != NULL, "No _dictionary?");
+  assert_locked();
+  size_t res = _dictionary->maxChunkSize();
+  res = MAX2(res, MIN2(_smallLinearAllocBlock._word_size,
+                       (size_t) SmallForLinearAlloc - 1));
+  // XXX the following could potentially be pretty slow;
+  // should one, pesimally for the rare cases when res
+  // caclulated above is less than IndexSetSize,
+  // just return res calculated above? My reasoning was that
+  // those cases will be so rare that the extra time spent doesn't
+  // really matter....
+  // Note: do not change the loop test i >= res + IndexSetStride
+  // to i > res below, because i is unsigned and res may be zero.
+  for (size_t i = IndexSetSize - 1; i >= res + IndexSetStride;
+       i -= IndexSetStride) {
+    if (_indexedFreeList[i].head() != NULL) {
+      assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList");
+      return i;
+    }
+  }
+  return res;
+}
+
+void CompactibleFreeListSpace::reportFreeListStatistics() const {
+  assert_lock_strong(&_freelistLock);
+  assert(PrintFLSStatistics != 0, "Reporting error");
+  _dictionary->reportStatistics();
+  if (PrintFLSStatistics > 1) {
+    reportIndexedFreeListStatistics();
+    size_t totalSize = totalSizeInIndexedFreeLists() +
+                       _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock()));
+    gclog_or_tty->print(" free=%ld frag=%1.4f\n", totalSize, flsFrag());
+  }
+}
+
+void CompactibleFreeListSpace::reportIndexedFreeListStatistics() const {
+  assert_lock_strong(&_freelistLock);
+  gclog_or_tty->print("Statistics for IndexedFreeLists:\n"
+                      "--------------------------------\n");
+  size_t totalSize = totalSizeInIndexedFreeLists();
+  size_t   freeBlocks = numFreeBlocksInIndexedFreeLists();
+  gclog_or_tty->print("Total Free Space: %d\n", totalSize);
+  gclog_or_tty->print("Max   Chunk Size: %d\n", maxChunkSizeInIndexedFreeLists());
+  gclog_or_tty->print("Number of Blocks: %d\n", freeBlocks);
+  if (freeBlocks != 0) {
+    gclog_or_tty->print("Av.  Block  Size: %d\n", totalSize/freeBlocks);
+  }
+}
+
+size_t CompactibleFreeListSpace::numFreeBlocksInIndexedFreeLists() const {
+  size_t res = 0;
+  for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    debug_only(
+      ssize_t recount = 0;
+      for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;
+         fc = fc->next()) {
+        recount += 1;
+      }
+      assert(recount == _indexedFreeList[i].count(),
+        "Incorrect count in list");
+    )
+    res += _indexedFreeList[i].count();
+  }
+  return res;
+}
+
+size_t CompactibleFreeListSpace::maxChunkSizeInIndexedFreeLists() const {
+  for (size_t i = IndexSetSize - 1; i != 0; i -= IndexSetStride) {
+    if (_indexedFreeList[i].head() != NULL) {
+      assert(_indexedFreeList[i].count() != 0, "Inconsistent FreeList");
+      return (size_t)i;
+    }
+  }
+  return 0;
+}
+
+void CompactibleFreeListSpace::set_end(HeapWord* value) {
+  HeapWord* prevEnd = end();
+  assert(prevEnd != value, "unnecessary set_end call");
+  assert(prevEnd == NULL || value >= unallocated_block(), "New end is below unallocated block");
+  _end = value;
+  if (prevEnd != NULL) {
+    // Resize the underlying block offset table.
+    _bt.resize(pointer_delta(value, bottom()));
+  if (value <= prevEnd) {
+    assert(value >= unallocated_block(), "New end is below unallocated block");
+  } else {
+    // Now, take this new chunk and add it to the free blocks.
+    // Note that the BOT has not yet been updated for this block.
+    size_t newFcSize = pointer_delta(value, prevEnd);
+    // XXX This is REALLY UGLY and should be fixed up. XXX
+    if (!_adaptive_freelists && _smallLinearAllocBlock._ptr == NULL) {
+      // Mark the boundary of the new block in BOT
+      _bt.mark_block(prevEnd, value);
+      // put it all in the linAB
+      if (ParallelGCThreads == 0) {
+        _smallLinearAllocBlock._ptr = prevEnd;
+        _smallLinearAllocBlock._word_size = newFcSize;
+        repairLinearAllocBlock(&_smallLinearAllocBlock);
+      } else { // ParallelGCThreads > 0
+        MutexLockerEx x(parDictionaryAllocLock(),
+                        Mutex::_no_safepoint_check_flag);
+        _smallLinearAllocBlock._ptr = prevEnd;
+        _smallLinearAllocBlock._word_size = newFcSize;
+        repairLinearAllocBlock(&_smallLinearAllocBlock);
+      }
+      // Births of chunks put into a LinAB are not recorded.  Births
+      // of chunks as they are allocated out of a LinAB are.
+    } else {
+      // Add the block to the free lists, if possible coalescing it
+      // with the last free block, and update the BOT and census data.
+      addChunkToFreeListsAtEndRecordingStats(prevEnd, newFcSize);
+    }
+  }
+  }
+}
+
+class FreeListSpace_DCTOC : public Filtering_DCTOC {
+  CompactibleFreeListSpace* _cfls;
+  CMSCollector* _collector;
+protected:
+  // Override.
+#define walk_mem_region_with_cl_DECL(ClosureType)                       \
+  virtual void walk_mem_region_with_cl(MemRegion mr,                    \
+                                       HeapWord* bottom, HeapWord* top, \
+                                       ClosureType* cl);                \
+      void walk_mem_region_with_cl_par(MemRegion mr,                    \
+                                       HeapWord* bottom, HeapWord* top, \
+                                       ClosureType* cl);                \
+    void walk_mem_region_with_cl_nopar(MemRegion mr,                    \
+                                       HeapWord* bottom, HeapWord* top, \
+                                       ClosureType* cl)
+  walk_mem_region_with_cl_DECL(OopClosure);
+  walk_mem_region_with_cl_DECL(FilteringClosure);
+
+public:
+  FreeListSpace_DCTOC(CompactibleFreeListSpace* sp,
+                      CMSCollector* collector,
+                      OopClosure* cl,
+                      CardTableModRefBS::PrecisionStyle precision,
+                      HeapWord* boundary) :
+    Filtering_DCTOC(sp, cl, precision, boundary),
+    _cfls(sp), _collector(collector) {}
+};
+
+// We de-virtualize the block-related calls below, since we know that our
+// space is a CompactibleFreeListSpace.
+#define FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(ClosureType)          \
+void FreeListSpace_DCTOC::walk_mem_region_with_cl(MemRegion mr,                 \
+                                                 HeapWord* bottom,              \
+                                                 HeapWord* top,                 \
+                                                 ClosureType* cl) {             \
+   if (SharedHeap::heap()->n_par_threads() > 0) {                               \
+     walk_mem_region_with_cl_par(mr, bottom, top, cl);                          \
+   } else {                                                                     \
+     walk_mem_region_with_cl_nopar(mr, bottom, top, cl);                        \
+   }                                                                            \
+}                                                                               \
+void FreeListSpace_DCTOC::walk_mem_region_with_cl_par(MemRegion mr,             \
+                                                      HeapWord* bottom,         \
+                                                      HeapWord* top,            \
+                                                      ClosureType* cl) {        \
+  /* Skip parts that are before "mr", in case "block_start" sent us             \
+     back too far. */                                                           \
+  HeapWord* mr_start = mr.start();                                              \
+  size_t bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom);        \
+  HeapWord* next = bottom + bot_size;                                           \
+  while (next < mr_start) {                                                     \
+    bottom = next;                                                              \
+    bot_size = _cfls->CompactibleFreeListSpace::block_size(bottom);             \
+    next = bottom + bot_size;                                                   \
+  }                                                                             \
+                                                                                \
+  while (bottom < top) {                                                        \
+    if (_cfls->CompactibleFreeListSpace::block_is_obj(bottom) &&                \
+        !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks(       \
+                    oop(bottom)) &&                                             \
+        !_collector->CMSCollector::is_dead_obj(oop(bottom))) {                  \
+      size_t word_sz = oop(bottom)->oop_iterate(cl, mr);                        \
+      bottom += _cfls->adjustObjectSize(word_sz);                               \
+    } else {                                                                    \
+      bottom += _cfls->CompactibleFreeListSpace::block_size(bottom);            \
+    }                                                                           \
+  }                                                                             \
+}                                                                               \
+void FreeListSpace_DCTOC::walk_mem_region_with_cl_nopar(MemRegion mr,           \
+                                                        HeapWord* bottom,       \
+                                                        HeapWord* top,          \
+                                                        ClosureType* cl) {      \
+  /* Skip parts that are before "mr", in case "block_start" sent us             \
+     back too far. */                                                           \
+  HeapWord* mr_start = mr.start();                                              \
+  size_t bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom);  \
+  HeapWord* next = bottom + bot_size;                                           \
+  while (next < mr_start) {                                                     \
+    bottom = next;                                                              \
+    bot_size = _cfls->CompactibleFreeListSpace::block_size_nopar(bottom);       \
+    next = bottom + bot_size;                                                   \
+  }                                                                             \
+                                                                                \
+  while (bottom < top) {                                                        \
+    if (_cfls->CompactibleFreeListSpace::block_is_obj_nopar(bottom) &&          \
+        !_cfls->CompactibleFreeListSpace::obj_allocated_since_save_marks(       \
+                    oop(bottom)) &&                                             \
+        !_collector->CMSCollector::is_dead_obj(oop(bottom))) {                  \
+      size_t word_sz = oop(bottom)->oop_iterate(cl, mr);                        \
+      bottom += _cfls->adjustObjectSize(word_sz);                               \
+    } else {                                                                    \
+      bottom += _cfls->CompactibleFreeListSpace::block_size_nopar(bottom);      \
+    }                                                                           \
+  }                                                                             \
+}
+
+// (There are only two of these, rather than N, because the split is due
+// only to the introduction of the FilteringClosure, a local part of the
+// impl of this abstraction.)
+FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(OopClosure)
+FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure)
+
+DirtyCardToOopClosure*
+CompactibleFreeListSpace::new_dcto_cl(OopClosure* cl,
+                                      CardTableModRefBS::PrecisionStyle precision,
+                                      HeapWord* boundary) {
+  return new FreeListSpace_DCTOC(this, _collector, cl, precision, boundary);
+}
+
+
+// Note on locking for the space iteration functions:
+// since the collector's iteration activities are concurrent with
+// allocation activities by mutators, absent a suitable mutual exclusion
+// mechanism the iterators may go awry. For instace a block being iterated
+// may suddenly be allocated or divided up and part of it allocated and
+// so on.
+
+// Apply the given closure to each block in the space.
+void CompactibleFreeListSpace::blk_iterate_careful(BlkClosureCareful* cl) {
+  assert_lock_strong(freelistLock());
+  HeapWord *cur, *limit;
+  for (cur = bottom(), limit = end(); cur < limit;
+       cur += cl->do_blk_careful(cur));
+}
+
+// Apply the given closure to each block in the space.
+void CompactibleFreeListSpace::blk_iterate(BlkClosure* cl) {
+  assert_lock_strong(freelistLock());
+  HeapWord *cur, *limit;
+  for (cur = bottom(), limit = end(); cur < limit;
+       cur += cl->do_blk(cur));
+}
+
+// Apply the given closure to each oop in the space.
+void CompactibleFreeListSpace::oop_iterate(OopClosure* cl) {
+  assert_lock_strong(freelistLock());
+  HeapWord *cur, *limit;
+  size_t curSize;
+  for (cur = bottom(), limit = end(); cur < limit;
+       cur += curSize) {
+    curSize = block_size(cur);
+    if (block_is_obj(cur)) {
+      oop(cur)->oop_iterate(cl);
+    }
+  }
+}
+
+// Apply the given closure to each oop in the space \intersect memory region.
+void CompactibleFreeListSpace::oop_iterate(MemRegion mr, OopClosure* cl) {
+  assert_lock_strong(freelistLock());
+  if (is_empty()) {
+    return;
+  }
+  MemRegion cur = MemRegion(bottom(), end());
+  mr = mr.intersection(cur);
+  if (mr.is_empty()) {
+    return;
+  }
+  if (mr.equals(cur)) {
+    oop_iterate(cl);
+    return;
+  }
+  assert(mr.end() <= end(), "just took an intersection above");
+  HeapWord* obj_addr = block_start(mr.start());
+  HeapWord* t = mr.end();
+
+  SpaceMemRegionOopsIterClosure smr_blk(cl, mr);
+  if (block_is_obj(obj_addr)) {
+    // Handle first object specially.
+    oop obj = oop(obj_addr);
+    obj_addr += adjustObjectSize(obj->oop_iterate(&smr_blk));
+  } else {
+    FreeChunk* fc = (FreeChunk*)obj_addr;
+    obj_addr += fc->size();
+  }
+  while (obj_addr < t) {
+    HeapWord* obj = obj_addr;
+    obj_addr += block_size(obj_addr);
+    // If "obj_addr" is not greater than top, then the
+    // entire object "obj" is within the region.
+    if (obj_addr <= t) {
+      if (block_is_obj(obj)) {
+        oop(obj)->oop_iterate(cl);
+      }
+    } else {
+      // "obj" extends beyond end of region
+      if (block_is_obj(obj)) {
+        oop(obj)->oop_iterate(&smr_blk);
+      }
+      break;
+    }
+  }
+}
+
+// NOTE: In the following methods, in order to safely be able to
+// apply the closure to an object, we need to be sure that the
+// object has been initialized. We are guaranteed that an object
+// is initialized if we are holding the Heap_lock with the
+// world stopped.
+void CompactibleFreeListSpace::verify_objects_initialized() const {
+  if (is_init_completed()) {
+    assert_locked_or_safepoint(Heap_lock);
+    if (Universe::is_fully_initialized()) {
+      guarantee(SafepointSynchronize::is_at_safepoint(),
+                "Required for objects to be initialized");
+    }
+  } // else make a concession at vm start-up
+}
+
+// Apply the given closure to each object in the space
+void CompactibleFreeListSpace::object_iterate(ObjectClosure* blk) {
+  assert_lock_strong(freelistLock());
+  NOT_PRODUCT(verify_objects_initialized());
+  HeapWord *cur, *limit;
+  size_t curSize;
+  for (cur = bottom(), limit = end(); cur < limit;
+       cur += curSize) {
+    curSize = block_size(cur);
+    if (block_is_obj(cur)) {
+      blk->do_object(oop(cur));
+    }
+  }
+}
+
+void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr,
+                                                  UpwardsObjectClosure* cl) {
+  assert_locked();
+  NOT_PRODUCT(verify_objects_initialized());
+  Space::object_iterate_mem(mr, cl);
+}
+
+// Callers of this iterator beware: The closure application should
+// be robust in the face of uninitialized objects and should (always)
+// return a correct size so that the next addr + size below gives us a
+// valid block boundary. [See for instance,
+// ScanMarkedObjectsAgainCarefullyClosure::do_object_careful()
+// in ConcurrentMarkSweepGeneration.cpp.]
+HeapWord*
+CompactibleFreeListSpace::object_iterate_careful(ObjectClosureCareful* cl) {
+  assert_lock_strong(freelistLock());
+  HeapWord *addr, *last;
+  size_t size;
+  for (addr = bottom(), last  = end();
+       addr < last; addr += size) {
+    FreeChunk* fc = (FreeChunk*)addr;
+    if (fc->isFree()) {
+      // Since we hold the free list lock, which protects direct
+      // allocation in this generation by mutators, a free object
+      // will remain free throughout this iteration code.
+      size = fc->size();
+    } else {
+      // Note that the object need not necessarily be initialized,
+      // because (for instance) the free list lock does NOT protect
+      // object initialization. The closure application below must
+      // therefore be correct in the face of uninitialized objects.
+      size = cl->do_object_careful(oop(addr));
+      if (size == 0) {
+        // An unparsable object found. Signal early termination.
+        return addr;
+      }
+    }
+  }
+  return NULL;
+}
+
+// Callers of this iterator beware: The closure application should
+// be robust in the face of uninitialized objects and should (always)
+// return a correct size so that the next addr + size below gives us a
+// valid block boundary. [See for instance,
+// ScanMarkedObjectsAgainCarefullyClosure::do_object_careful()
+// in ConcurrentMarkSweepGeneration.cpp.]
+HeapWord*
+CompactibleFreeListSpace::object_iterate_careful_m(MemRegion mr,
+  ObjectClosureCareful* cl) {
+  assert_lock_strong(freelistLock());
+  // Can't use used_region() below because it may not necessarily
+  // be the same as [bottom(),end()); although we could
+  // use [used_region().start(),round_to(used_region().end(),CardSize)),
+  // that appears too cumbersome, so we just do the simpler check
+  // in the assertion below.
+  assert(!mr.is_empty() && MemRegion(bottom(),end()).contains(mr),
+         "mr should be non-empty and within used space");
+  HeapWord *addr, *end;
+  size_t size;
+  for (addr = block_start_careful(mr.start()), end  = mr.end();
+       addr < end; addr += size) {
+    FreeChunk* fc = (FreeChunk*)addr;
+    if (fc->isFree()) {
+      // Since we hold the free list lock, which protects direct
+      // allocation in this generation by mutators, a free object
+      // will remain free throughout this iteration code.
+      size = fc->size();
+    } else {
+      // Note that the object need not necessarily be initialized,
+      // because (for instance) the free list lock does NOT protect
+      // object initialization. The closure application below must
+      // therefore be correct in the face of uninitialized objects.
+      size = cl->do_object_careful_m(oop(addr), mr);
+      if (size == 0) {
+        // An unparsable object found. Signal early termination.
+        return addr;
+      }
+    }
+  }
+  return NULL;
+}
+
+
+HeapWord* CompactibleFreeListSpace::block_start(const void* p) const {
+  NOT_PRODUCT(verify_objects_initialized());
+  return _bt.block_start(p);
+}
+
+HeapWord* CompactibleFreeListSpace::block_start_careful(const void* p) const {
+  return _bt.block_start_careful(p);
+}
+
+size_t CompactibleFreeListSpace::block_size(const HeapWord* p) const {
+  NOT_PRODUCT(verify_objects_initialized());
+  assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+  // This must be volatile, or else there is a danger that the compiler
+  // will compile the code below into a sometimes-infinite loop, by keeping
+  // the value read the first time in a register.
+  oop o = (oop)p;
+  volatile oop* second_word_addr = o->klass_addr();
+  while (true) {
+    klassOop k = (klassOop)(*second_word_addr);
+    // We must do this until we get a consistent view of the object.
+    if (FreeChunk::secondWordIndicatesFreeChunk((intptr_t)k)) {
+      FreeChunk* fc = (FreeChunk*)p;
+      volatile size_t* sz_addr = (volatile size_t*)(fc->size_addr());
+      size_t res = (*sz_addr);
+      klassOop k2 = (klassOop)(*second_word_addr);  // Read to confirm.
+      if (k == k2) {
+        assert(res != 0, "Block size should not be 0");
+        return res;
+      }
+    } else if (k != NULL) {
+      assert(k->is_oop(true /* ignore mark word */), "Should really be klass oop.");
+      assert(o->is_parsable(), "Should be parsable");
+      assert(o->is_oop(true /* ignore mark word */), "Should be an oop.");
+      size_t res = o->size_given_klass(k->klass_part());
+      res = adjustObjectSize(res);
+      assert(res != 0, "Block size should not be 0");
+      return res;
+    }
+  }
+}
+
+// A variant of the above that uses the Printezis bits for
+// unparsable but allocated objects. This avoids any possible
+// stalls waiting for mutators to initialize objects, and is
+// thus potentially faster than the variant above. However,
+// this variant may return a zero size for a block that is
+// under mutation and for which a consistent size cannot be
+// inferred without stalling; see CMSCollector::block_size_if_printezis_bits().
+size_t CompactibleFreeListSpace::block_size_no_stall(HeapWord* p,
+                                                     const CMSCollector* c)
+const {
+  assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+  // This must be volatile, or else there is a danger that the compiler
+  // will compile the code below into a sometimes-infinite loop, by keeping
+  // the value read the first time in a register.
+  oop o = (oop)p;
+  volatile oop* second_word_addr = o->klass_addr();
+  DEBUG_ONLY(uint loops = 0;)
+  while (true) {
+    klassOop k = (klassOop)(*second_word_addr);
+    // We must do this until we get a consistent view of the object.
+    if (FreeChunk::secondWordIndicatesFreeChunk((intptr_t)k)) {
+      FreeChunk* fc = (FreeChunk*)p;
+      volatile size_t* sz_addr = (volatile size_t*)(fc->size_addr());
+      size_t res = (*sz_addr);
+      klassOop k2 = (klassOop)(*second_word_addr);  // Read to confirm.
+      if (k == k2) {
+        assert(res != 0, "Block size should not be 0");
+        assert(loops == 0, "Should be 0");
+        return res;
+      }
+    } else if (k != NULL && o->is_parsable()) {
+      assert(k->is_oop(), "Should really be klass oop.");
+      assert(o->is_oop(), "Should be an oop");
+      size_t res = o->size_given_klass(k->klass_part());
+      res = adjustObjectSize(res);
+      assert(res != 0, "Block size should not be 0");
+      return res;
+    } else {
+      return c->block_size_if_printezis_bits(p);
+    }
+    assert(loops == 0, "Can loop at most once");
+    DEBUG_ONLY(loops++;)
+  }
+}
+
+size_t CompactibleFreeListSpace::block_size_nopar(const HeapWord* p) const {
+  NOT_PRODUCT(verify_objects_initialized());
+  assert(MemRegion(bottom(), end()).contains(p), "p not in space");
+  FreeChunk* fc = (FreeChunk*)p;
+  if (fc->isFree()) {
+    return fc->size();
+  } else {
+    // Ignore mark word because this may be a recently promoted
+    // object whose mark word is used to chain together grey
+    // objects (the last one would have a null value).
+    assert(oop(p)->is_oop(true), "Should be an oop");
+    return adjustObjectSize(oop(p)->size());
+  }
+}
+
+// This implementation assumes that the property of "being an object" is
+// stable.  But being a free chunk may not be (because of parallel
+// promotion.)
+bool CompactibleFreeListSpace::block_is_obj(const HeapWord* p) const {
+  FreeChunk* fc = (FreeChunk*)p;
+  assert(is_in_reserved(p), "Should be in space");
+  // When doing a mark-sweep-compact of the CMS generation, this
+  // assertion may fail because prepare_for_compaction() uses
+  // space that is garbage to maintain information on ranges of
+  // live objects so that these live ranges can be moved as a whole.
+  // Comment out this assertion until that problem can be solved
+  // (i.e., that the block start calculation may look at objects
+  // at address below "p" in finding the object that contains "p"
+  // and those objects (if garbage) may have been modified to hold
+  // live range information.
+  // assert(ParallelGCThreads > 0 || _bt.block_start(p) == p, "Should be a block boundary");
+  klassOop k = oop(p)->klass();
+  intptr_t ki = (intptr_t)k;
+  if (FreeChunk::secondWordIndicatesFreeChunk(ki)) return false;
+  if (k != NULL) {
+    // Ignore mark word because it may have been used to
+    // chain together promoted objects (the last one
+    // would have a null value).
+    assert(oop(p)->is_oop(true), "Should be an oop");
+    return true;
+  } else {
+    return false;  // Was not an object at the start of collection.
+  }
+}
+
+// Check if the object is alive. This fact is checked either by consulting
+// the main marking bitmap in the sweeping phase or, if it's a permanent
+// generation and we're not in the sweeping phase, by checking the
+// perm_gen_verify_bit_map where we store the "deadness" information if
+// we did not sweep the perm gen in the most recent previous GC cycle.
+bool CompactibleFreeListSpace::obj_is_alive(const HeapWord* p) const {
+  assert (block_is_obj(p), "The address should point to an object");
+
+  // If we're sweeping, we use object liveness information from the main bit map
+  // for both perm gen and old gen.
+  // We don't need to lock the bitmap (live_map or dead_map below), because
+  // EITHER we are in the middle of the sweeping phase, and the
+  // main marking bit map (live_map below) is locked,
+  // OR we're in other phases and perm_gen_verify_bit_map (dead_map below)
+  // is stable, because it's mutated only in the sweeping phase.
+  if (_collector->abstract_state() == CMSCollector::Sweeping) {
+    CMSBitMap* live_map = _collector->markBitMap();
+    return live_map->isMarked((HeapWord*) p);
+  } else {
+    // If we're not currently sweeping and we haven't swept the perm gen in
+    // the previous concurrent cycle then we may have dead but unswept objects
+    // in the perm gen. In this case, we use the "deadness" information
+    // that we had saved in perm_gen_verify_bit_map at the last sweep.
+    if (!CMSClassUnloadingEnabled && _collector->_permGen->reserved().contains(p)) {
+      if (_collector->verifying()) {
+        CMSBitMap* dead_map = _collector->perm_gen_verify_bit_map();
+        // Object is marked in the dead_map bitmap at the previous sweep
+        // when we know that it's dead; if the bitmap is not allocated then
+        // the object is alive.
+        return (dead_map->sizeInBits() == 0) // bit_map has been allocated
+               || !dead_map->par_isMarked((HeapWord*) p);
+      } else {
+        return false; // We can't say for sure if it's live, so we say that it's dead.
+      }
+    }
+  }
+  return true;
+}
+
+bool CompactibleFreeListSpace::block_is_obj_nopar(const HeapWord* p) const {
+  FreeChunk* fc = (FreeChunk*)p;
+  assert(is_in_reserved(p), "Should be in space");
+  assert(_bt.block_start(p) == p, "Should be a block boundary");
+  if (!fc->isFree()) {
+    // Ignore mark word because it may have been used to
+    // chain together promoted objects (the last one
+    // would have a null value).
+    assert(oop(p)->is_oop(true), "Should be an oop");
+    return true;
+  }
+  return false;
+}
+
+// "MT-safe but not guaranteed MT-precise" (TM); you may get an
+// approximate answer if you don't hold the freelistlock when you call this.
+size_t CompactibleFreeListSpace::totalSizeInIndexedFreeLists() const {
+  size_t size = 0;
+  for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    debug_only(
+      // We may be calling here without the lock in which case we
+      // won't do this modest sanity check.
+      if (freelistLock()->owned_by_self()) {
+        size_t total_list_size = 0;
+        for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;
+          fc = fc->next()) {
+          total_list_size += i;
+        }
+        assert(total_list_size == i * _indexedFreeList[i].count(),
+               "Count in list is incorrect");
+      }
+    )
+    size += i * _indexedFreeList[i].count();
+  }
+  return size;
+}
+
+HeapWord* CompactibleFreeListSpace::par_allocate(size_t size) {
+  MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag);
+  return allocate(size);
+}
+
+HeapWord*
+CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlockRemainder(size_t size) {
+  return getChunkFromLinearAllocBlockRemainder(&_smallLinearAllocBlock, size);
+}
+
+HeapWord* CompactibleFreeListSpace::allocate(size_t size) {
+  assert_lock_strong(freelistLock());
+  HeapWord* res = NULL;
+  assert(size == adjustObjectSize(size),
+         "use adjustObjectSize() before calling into allocate()");
+
+  if (_adaptive_freelists) {
+    res = allocate_adaptive_freelists(size);
+  } else {  // non-adaptive free lists
+    res = allocate_non_adaptive_freelists(size);
+  }
+
+  if (res != NULL) {
+    // check that res does lie in this space!
+    assert(is_in_reserved(res), "Not in this space!");
+    assert(is_aligned((void*)res), "alignment check");
+
+    FreeChunk* fc = (FreeChunk*)res;
+    fc->markNotFree();
+    assert(!fc->isFree(), "shouldn't be marked free");
+    assert(oop(fc)->klass() == NULL, "should look uninitialized");
+    // Verify that the block offset table shows this to
+    // be a single block, but not one which is unallocated.
+    _bt.verify_single_block(res, size);
+    _bt.verify_not_unallocated(res, size);
+    // mangle a just allocated object with a distinct pattern.
+    debug_only(fc->mangleAllocated(size));
+  }
+
+  return res;
+}
+
+HeapWord* CompactibleFreeListSpace::allocate_non_adaptive_freelists(size_t size) {
+  HeapWord* res = NULL;
+  // try and use linear allocation for smaller blocks
+  if (size < _smallLinearAllocBlock._allocation_size_limit) {
+    // if successful, the following also adjusts block offset table
+    res = getChunkFromSmallLinearAllocBlock(size);
+  }
+  // Else triage to indexed lists for smaller sizes
+  if (res == NULL) {
+    if (size < SmallForDictionary) {
+      res = (HeapWord*) getChunkFromIndexedFreeList(size);
+    } else {
+      // else get it from the big dictionary; if even this doesn't
+      // work we are out of luck.
+      res = (HeapWord*)getChunkFromDictionaryExact(size);
+    }
+  }
+
+  return res;
+}
+
+HeapWord* CompactibleFreeListSpace::allocate_adaptive_freelists(size_t size) {
+  assert_lock_strong(freelistLock());
+  HeapWord* res = NULL;
+  assert(size == adjustObjectSize(size),
+         "use adjustObjectSize() before calling into allocate()");
+
+  // Strategy
+  //   if small
+  //     exact size from small object indexed list if small
+  //     small or large linear allocation block (linAB) as appropriate
+  //     take from lists of greater sized chunks
+  //   else
+  //     dictionary
+  //     small or large linear allocation block if it has the space
+  // Try allocating exact size from indexTable first
+  if (size < IndexSetSize) {
+    res = (HeapWord*) getChunkFromIndexedFreeList(size);
+    if(res != NULL) {
+      assert(res != (HeapWord*)_indexedFreeList[size].head(),
+        "Not removed from free list");
+      // no block offset table adjustment is necessary on blocks in
+      // the indexed lists.
+
+    // Try allocating from the small LinAB
+    } else if (size < _smallLinearAllocBlock._allocation_size_limit &&
+        (res = getChunkFromSmallLinearAllocBlock(size)) != NULL) {
+        // if successful, the above also adjusts block offset table
+        // Note that this call will refill the LinAB to
+        // satisfy the request.  This is different that
+        // evm.
+        // Don't record chunk off a LinAB?  smallSplitBirth(size);
+
+    } else {
+      // Raid the exact free lists larger than size, even if they are not
+      // overpopulated.
+      res = (HeapWord*) getChunkFromGreater(size);
+    }
+  } else {
+    // Big objects get allocated directly from the dictionary.
+    res = (HeapWord*) getChunkFromDictionaryExact(size);
+    if (res == NULL) {
+      // Try hard not to fail since an allocation failure will likely
+      // trigger a synchronous GC.  Try to get the space from the
+      // allocation blocks.
+      res = getChunkFromSmallLinearAllocBlockRemainder(size);
+    }
+  }
+
+  return res;
+}
+
+// A worst-case estimate of the space required (in HeapWords) to expand the heap
+// when promoting obj.
+size_t CompactibleFreeListSpace::expansionSpaceRequired(size_t obj_size) const {
+  // Depending on the object size, expansion may require refilling either a
+  // bigLAB or a smallLAB plus refilling a PromotionInfo object.  MinChunkSize
+  // is added because the dictionary may over-allocate to avoid fragmentation.
+  size_t space = obj_size;
+  if (!_adaptive_freelists) {
+    space = MAX2(space, _smallLinearAllocBlock._refillSize);
+  }
+  space += _promoInfo.refillSize() + 2 * MinChunkSize;
+  return space;
+}
+
+FreeChunk* CompactibleFreeListSpace::getChunkFromGreater(size_t numWords) {
+  FreeChunk* ret;
+
+  assert(numWords >= MinChunkSize, "Size is less than minimum");
+  assert(linearAllocationWouldFail() || bestFitFirst(),
+    "Should not be here");
+
+  size_t i;
+  size_t currSize = numWords + MinChunkSize;
+  assert(currSize % MinObjAlignment == 0, "currSize should be aligned");
+  for (i = currSize; i < IndexSetSize; i += IndexSetStride) {
+    FreeList* fl = &_indexedFreeList[i];
+    if (fl->head()) {
+      ret = getFromListGreater(fl, numWords);
+      assert(ret == NULL || ret->isFree(), "Should be returning a free chunk");
+      return ret;
+    }
+  }
+
+  currSize = MAX2((size_t)SmallForDictionary,
+                  (size_t)(numWords + MinChunkSize));
+
+  /* Try to get a chunk that satisfies request, while avoiding
+     fragmentation that can't be handled. */
+  {
+    ret =  dictionary()->getChunk(currSize);
+    if (ret != NULL) {
+      assert(ret->size() - numWords >= MinChunkSize,
+             "Chunk is too small");
+      _bt.allocated((HeapWord*)ret, ret->size());
+      /* Carve returned chunk. */
+      (void) splitChunkAndReturnRemainder(ret, numWords);
+      /* Label this as no longer a free chunk. */
+      assert(ret->isFree(), "This chunk should be free");
+      ret->linkPrev(NULL);
+    }
+    assert(ret == NULL || ret->isFree(), "Should be returning a free chunk");
+    return ret;
+  }
+  ShouldNotReachHere();
+}
+
+bool CompactibleFreeListSpace::verifyChunkInIndexedFreeLists(FreeChunk* fc)
+  const {
+  assert(fc->size() < IndexSetSize, "Size of chunk is too large");
+  return _indexedFreeList[fc->size()].verifyChunkInFreeLists(fc);
+}
+
+bool CompactibleFreeListSpace::verifyChunkInFreeLists(FreeChunk* fc) const {
+  if (fc->size() >= IndexSetSize) {
+    return dictionary()->verifyChunkInFreeLists(fc);
+  } else {
+    return verifyChunkInIndexedFreeLists(fc);
+  }
+}
+
+#ifndef PRODUCT
+void CompactibleFreeListSpace::assert_locked() const {
+  CMSLockVerifier::assert_locked(freelistLock(), parDictionaryAllocLock());
+}
+#endif
+
+FreeChunk* CompactibleFreeListSpace::allocateScratch(size_t size) {
+  // In the parallel case, the main thread holds the free list lock
+  // on behalf the parallel threads.
+  assert_locked();
+  FreeChunk* fc;
+  {
+    // If GC is parallel, this might be called by several threads.
+    // This should be rare enough that the locking overhead won't affect
+    // the sequential code.
+    MutexLockerEx x(parDictionaryAllocLock(),
+                    Mutex::_no_safepoint_check_flag);
+    fc = getChunkFromDictionary(size);
+  }
+  if (fc != NULL) {
+    fc->dontCoalesce();
+    assert(fc->isFree(), "Should be free, but not coalescable");
+    // Verify that the block offset table shows this to
+    // be a single block, but not one which is unallocated.
+    _bt.verify_single_block((HeapWord*)fc, fc->size());
+    _bt.verify_not_unallocated((HeapWord*)fc, fc->size());
+  }
+  return fc;
+}
+
+oop CompactibleFreeListSpace::promote(oop obj, size_t obj_size, oop* ref) {
+  assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
+  assert_locked();
+
+  // if we are tracking promotions, then first ensure space for
+  // promotion (including spooling space for saving header if necessary).
+  // then allocate and copy, then track promoted info if needed.
+  // When tracking (see PromotionInfo::track()), the mark word may
+  // be displaced and in this case restoration of the mark word
+  // occurs in the (oop_since_save_marks_)iterate phase.
+  if (_promoInfo.tracking() && !_promoInfo.ensure_spooling_space()) {
+    return NULL;
+  }
+  // Call the allocate(size_t, bool) form directly to avoid the
+  // additional call through the allocate(size_t) form.  Having
+  // the compile inline the call is problematic because allocate(size_t)
+  // is a virtual method.
+  HeapWord* res = allocate(adjustObjectSize(obj_size));
+  if (res != NULL) {
+    Copy::aligned_disjoint_words((HeapWord*)obj, res, obj_size);
+    // if we should be tracking promotions, do so.
+    if (_promoInfo.tracking()) {
+        _promoInfo.track((PromotedObject*)res);
+    }
+  }
+  return oop(res);
+}
+
+HeapWord*
+CompactibleFreeListSpace::getChunkFromSmallLinearAllocBlock(size_t size) {
+  assert_locked();
+  assert(size >= MinChunkSize, "minimum chunk size");
+  assert(size <  _smallLinearAllocBlock._allocation_size_limit,
+    "maximum from smallLinearAllocBlock");
+  return getChunkFromLinearAllocBlock(&_smallLinearAllocBlock, size);
+}
+
+HeapWord*
+CompactibleFreeListSpace::getChunkFromLinearAllocBlock(LinearAllocBlock *blk,
+                                                       size_t size) {
+  assert_locked();
+  assert(size >= MinChunkSize, "too small");
+  HeapWord* res = NULL;
+  // Try to do linear allocation from blk, making sure that
+  if (blk->_word_size == 0) {
+    // We have probably been unable to fill this either in the prologue or
+    // when it was exhausted at the last linear allocation. Bail out until
+    // next time.
+    assert(blk->_ptr == NULL, "consistency check");
+    return NULL;
+  }
+  assert(blk->_word_size != 0 && blk->_ptr != NULL, "consistency check");
+  res = getChunkFromLinearAllocBlockRemainder(blk, size);
+  if (res != NULL) return res;
+
+  // about to exhaust this linear allocation block
+  if (blk->_word_size == size) { // exactly satisfied
+    res = blk->_ptr;
+    _bt.allocated(res, blk->_word_size);
+  } else if (size + MinChunkSize <= blk->_refillSize) {
+    // Update _unallocated_block if the size is such that chunk would be
+    // returned to the indexed free list.  All other chunks in the indexed
+    // free lists are allocated from the dictionary so that _unallocated_block
+    // has already been adjusted for them.  Do it here so that the cost
+    // for all chunks added back to the indexed free lists.
+    if (blk->_word_size < SmallForDictionary) {
+      _bt.allocated(blk->_ptr, blk->_word_size);
+    }
+    // Return the chunk that isn't big enough, and then refill below.
+    addChunkToFreeLists(blk->_ptr, blk->_word_size);
+    _bt.verify_single_block(blk->_ptr, (blk->_ptr + blk->_word_size));
+    // Don't keep statistics on adding back chunk from a LinAB.
+  } else {
+    // A refilled block would not satisfy the request.
+    return NULL;
+  }
+
+  blk->_ptr = NULL; blk->_word_size = 0;
+  refillLinearAllocBlock(blk);
+  assert(blk->_ptr == NULL || blk->_word_size >= size + MinChunkSize,
+         "block was replenished");
+  if (res != NULL) {
+    splitBirth(size);
+    repairLinearAllocBlock(blk);
+  } else if (blk->_ptr != NULL) {
+    res = blk->_ptr;
+    size_t blk_size = blk->_word_size;
+    blk->_word_size -= size;
+    blk->_ptr  += size;
+    splitBirth(size);
+    repairLinearAllocBlock(blk);
+    // Update BOT last so that other (parallel) GC threads see a consistent
+    // view of the BOT and free blocks.
+    // Above must occur before BOT is updated below.
+    _bt.split_block(res, blk_size, size);  // adjust block offset table
+  }
+  return res;
+}
+
+HeapWord*  CompactibleFreeListSpace::getChunkFromLinearAllocBlockRemainder(
+                                        LinearAllocBlock* blk,
+                                        size_t size) {
+  assert_locked();
+  assert(size >= MinChunkSize, "too small");
+
+  HeapWord* res = NULL;
+  // This is the common case.  Keep it simple.
+  if (blk->_word_size >= size + MinChunkSize) {
+    assert(blk->_ptr != NULL, "consistency check");
+    res = blk->_ptr;
+    // Note that the BOT is up-to-date for the linAB before allocation.  It
+    // indicates the start of the linAB.  The split_block() updates the
+    // BOT for the linAB after the allocation (indicates the start of the
+    // next chunk to be allocated).
+    size_t blk_size = blk->_word_size;
+    blk->_word_size -= size;
+    blk->_ptr  += size;
+    splitBirth(size);
+    repairLinearAllocBlock(blk);
+    // Update BOT last so that other (parallel) GC threads see a consistent
+    // view of the BOT and free blocks.
+    // Above must occur before BOT is updated below.
+    _bt.split_block(res, blk_size, size);  // adjust block offset table
+    _bt.allocated(res, size);
+  }
+  return res;
+}
+
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromIndexedFreeList(size_t size) {
+  assert_locked();
+  assert(size < SmallForDictionary, "just checking");
+  FreeChunk* res;
+  res = _indexedFreeList[size].getChunkAtHead();
+  if (res == NULL) {
+    res = getChunkFromIndexedFreeListHelper(size);
+  }
+  _bt.verify_not_unallocated((HeapWord*) res, size);
+  return res;
+}
+
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromIndexedFreeListHelper(size_t size) {
+  assert_locked();
+  FreeChunk* fc = NULL;
+  if (size < SmallForDictionary) {
+    assert(_indexedFreeList[size].head() == NULL ||
+      _indexedFreeList[size].surplus() <= 0,
+      "List for this size should be empty or under populated");
+    // Try best fit in exact lists before replenishing the list
+    if (!bestFitFirst() || (fc = bestFitSmall(size)) == NULL) {
+      // Replenish list.
+      //
+      // Things tried that failed.
+      //   Tried allocating out of the two LinAB's first before
+      // replenishing lists.
+      //   Tried small linAB of size 256 (size in indexed list)
+      // and replenishing indexed lists from the small linAB.
+      //
+      FreeChunk* newFc = NULL;
+      size_t replenish_size = CMSIndexedFreeListReplenish * size;
+      if (replenish_size < SmallForDictionary) {
+        // Do not replenish from an underpopulated size.
+        if (_indexedFreeList[replenish_size].surplus() > 0 &&
+            _indexedFreeList[replenish_size].head() != NULL) {
+          newFc =
+            _indexedFreeList[replenish_size].getChunkAtHead();
+        } else {
+          newFc = bestFitSmall(replenish_size);
+        }
+      }
+      if (newFc != NULL) {
+        splitDeath(replenish_size);
+      } else if (replenish_size > size) {
+        assert(CMSIndexedFreeListReplenish > 1, "ctl pt invariant");
+        newFc =
+          getChunkFromIndexedFreeListHelper(replenish_size);
+      }
+      if (newFc != NULL) {
+        assert(newFc->size() == replenish_size, "Got wrong size");
+        size_t i;
+        FreeChunk *curFc, *nextFc;
+        // carve up and link blocks 0, ..., CMSIndexedFreeListReplenish - 2
+        // The last chunk is not added to the lists but is returned as the
+        // free chunk.
+        for (curFc = newFc, nextFc = (FreeChunk*)((HeapWord*)curFc + size),
+             i = 0;
+             i < (CMSIndexedFreeListReplenish - 1);
+             curFc = nextFc, nextFc = (FreeChunk*)((HeapWord*)nextFc + size),
+             i++) {
+          curFc->setSize(size);
+          // Don't record this as a return in order to try and
+          // determine the "returns" from a GC.
+          _bt.verify_not_unallocated((HeapWord*) fc, size);
+          _indexedFreeList[size].returnChunkAtTail(curFc, false);
+          _bt.mark_block((HeapWord*)curFc, size);
+          splitBirth(size);
+          // Don't record the initial population of the indexed list
+          // as a split birth.
+        }
+
+        // check that the arithmetic was OK above
+        assert((HeapWord*)nextFc == (HeapWord*)newFc + replenish_size,
+          "inconsistency in carving newFc");
+        curFc->setSize(size);
+        _bt.mark_block((HeapWord*)curFc, size);
+        splitBirth(size);
+        return curFc;
+      }
+    }
+  } else {
+    // Get a free chunk from the free chunk dictionary to be returned to
+    // replenish the indexed free list.
+    fc = getChunkFromDictionaryExact(size);
+  }
+  assert(fc == NULL || fc->isFree(), "Should be returning a free chunk");
+  return fc;
+}
+
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromDictionary(size_t size) {
+  assert_locked();
+  FreeChunk* fc = _dictionary->getChunk(size);
+  if (fc == NULL) {
+    return NULL;
+  }
+  _bt.allocated((HeapWord*)fc, fc->size());
+  if (fc->size() >= size + MinChunkSize) {
+    fc = splitChunkAndReturnRemainder(fc, size);
+  }
+  assert(fc->size() >= size, "chunk too small");
+  assert(fc->size() < size + MinChunkSize, "chunk too big");
+  _bt.verify_single_block((HeapWord*)fc, fc->size());
+  return fc;
+}
+
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromDictionaryExact(size_t size) {
+  assert_locked();
+  FreeChunk* fc = _dictionary->getChunk(size);
+  if (fc == NULL) {
+    return fc;
+  }
+  _bt.allocated((HeapWord*)fc, fc->size());
+  if (fc->size() == size) {
+    _bt.verify_single_block((HeapWord*)fc, size);
+    return fc;
+  }
+  assert(fc->size() > size, "getChunk() guarantee");
+  if (fc->size() < size + MinChunkSize) {
+    // Return the chunk to the dictionary and go get a bigger one.
+    returnChunkToDictionary(fc);
+    fc = _dictionary->getChunk(size + MinChunkSize);
+    if (fc == NULL) {
+      return NULL;
+    }
+    _bt.allocated((HeapWord*)fc, fc->size());
+  }
+  assert(fc->size() >= size + MinChunkSize, "tautology");
+  fc = splitChunkAndReturnRemainder(fc, size);
+  assert(fc->size() == size, "chunk is wrong size");
+  _bt.verify_single_block((HeapWord*)fc, size);
+  return fc;
+}
+
+void
+CompactibleFreeListSpace::returnChunkToDictionary(FreeChunk* chunk) {
+  assert_locked();
+
+  size_t size = chunk->size();
+  _bt.verify_single_block((HeapWord*)chunk, size);
+  // adjust _unallocated_block downward, as necessary
+  _bt.freed((HeapWord*)chunk, size);
+  _dictionary->returnChunk(chunk);
+}
+
+void
+CompactibleFreeListSpace::returnChunkToFreeList(FreeChunk* fc) {
+  assert_locked();
+  size_t size = fc->size();
+  _bt.verify_single_block((HeapWord*) fc, size);
+  _bt.verify_not_unallocated((HeapWord*) fc, size);
+  if (_adaptive_freelists) {
+    _indexedFreeList[size].returnChunkAtTail(fc);
+  } else {
+    _indexedFreeList[size].returnChunkAtHead(fc);
+  }
+}
+
+// Add chunk to end of last block -- if it's the largest
+// block -- and update BOT and census data. We would
+// of course have preferred to coalesce it with the
+// last block, but it's currently less expensive to find the
+// largest block than it is to find the last.
+void
+CompactibleFreeListSpace::addChunkToFreeListsAtEndRecordingStats(
+  HeapWord* chunk, size_t     size) {
+  // check that the chunk does lie in this space!
+  assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!");
+  assert_locked();
+  // One of the parallel gc task threads may be here
+  // whilst others are allocating.
+  Mutex* lock = NULL;
+  if (ParallelGCThreads != 0) {
+    lock = &_parDictionaryAllocLock;
+  }
+  FreeChunk* ec;
+  {
+    MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag);
+    ec = dictionary()->findLargestDict();  // get largest block
+    if (ec != NULL && ec->end() == chunk) {
+      // It's a coterminal block - we can coalesce.
+      size_t old_size = ec->size();
+      coalDeath(old_size);
+      removeChunkFromDictionary(ec);
+      size += old_size;
+    } else {
+      ec = (FreeChunk*)chunk;
+    }
+  }
+  ec->setSize(size);
+  debug_only(ec->mangleFreed(size));
+  if (size < SmallForDictionary) {
+    lock = _indexedFreeListParLocks[size];
+  }
+  MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag);
+  addChunkAndRepairOffsetTable((HeapWord*)ec, size, true);
+  // record the birth under the lock since the recording involves
+  // manipulation of the list on which the chunk lives and
+  // if the chunk is allocated and is the last on the list,
+  // the list can go away.
+  coalBirth(size);
+}
+
+void
+CompactibleFreeListSpace::addChunkToFreeLists(HeapWord* chunk,
+                                              size_t     size) {
+  // check that the chunk does lie in this space!
+  assert(chunk != NULL && is_in_reserved(chunk), "Not in this space!");
+  assert_locked();
+  _bt.verify_single_block(chunk, size);
+
+  FreeChunk* fc = (FreeChunk*) chunk;
+  fc->setSize(size);
+  debug_only(fc->mangleFreed(size));
+  if (size < SmallForDictionary) {
+    returnChunkToFreeList(fc);
+  } else {
+    returnChunkToDictionary(fc);
+  }
+}
+
+void
+CompactibleFreeListSpace::addChunkAndRepairOffsetTable(HeapWord* chunk,
+  size_t size, bool coalesced) {
+  assert_locked();
+  assert(chunk != NULL, "null chunk");
+  if (coalesced) {
+    // repair BOT
+    _bt.single_block(chunk, size);
+  }
+  addChunkToFreeLists(chunk, size);
+}
+
+// We _must_ find the purported chunk on our free lists;
+// we assert if we don't.
+void
+CompactibleFreeListSpace::removeFreeChunkFromFreeLists(FreeChunk* fc) {
+  size_t size = fc->size();
+  assert_locked();
+  debug_only(verifyFreeLists());
+  if (size < SmallForDictionary) {
+    removeChunkFromIndexedFreeList(fc);
+  } else {
+    removeChunkFromDictionary(fc);
+  }
+  _bt.verify_single_block((HeapWord*)fc, size);
+  debug_only(verifyFreeLists());
+}
+
+void
+CompactibleFreeListSpace::removeChunkFromDictionary(FreeChunk* fc) {
+  size_t size = fc->size();
+  assert_locked();
+  assert(fc != NULL, "null chunk");
+  _bt.verify_single_block((HeapWord*)fc, size);
+  _dictionary->removeChunk(fc);
+  // adjust _unallocated_block upward, as necessary
+  _bt.allocated((HeapWord*)fc, size);
+}
+
+void
+CompactibleFreeListSpace::removeChunkFromIndexedFreeList(FreeChunk* fc) {
+  assert_locked();
+  size_t size = fc->size();
+  _bt.verify_single_block((HeapWord*)fc, size);
+  NOT_PRODUCT(
+    if (FLSVerifyIndexTable) {
+      verifyIndexedFreeList(size);
+    }
+  )
+  _indexedFreeList[size].removeChunk(fc);
+  debug_only(fc->clearNext());
+  debug_only(fc->clearPrev());
+  NOT_PRODUCT(
+    if (FLSVerifyIndexTable) {
+      verifyIndexedFreeList(size);
+    }
+  )
+}
+
+FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) {
+  /* A hint is the next larger size that has a surplus.
+     Start search at a size large enough to guarantee that
+     the excess is >= MIN_CHUNK. */
+  size_t start = align_object_size(numWords + MinChunkSize);
+  if (start < IndexSetSize) {
+    FreeList* it   = _indexedFreeList;
+    size_t    hint = _indexedFreeList[start].hint();
+    while (hint < IndexSetSize) {
+      assert(hint % MinObjAlignment == 0, "hint should be aligned");
+      FreeList *fl = &_indexedFreeList[hint];
+      if (fl->surplus() > 0 && fl->head() != NULL) {
+        // Found a list with surplus, reset original hint
+        // and split out a free chunk which is returned.
+        _indexedFreeList[start].set_hint(hint);
+        FreeChunk* res = getFromListGreater(fl, numWords);
+        assert(res == NULL || res->isFree(),
+          "Should be returning a free chunk");
+        return res;
+      }
+      hint = fl->hint(); /* keep looking */
+    }
+    /* None found. */
+    it[start].set_hint(IndexSetSize);
+  }
+  return NULL;
+}
+
+/* Requires fl->size >= numWords + MinChunkSize */
+FreeChunk* CompactibleFreeListSpace::getFromListGreater(FreeList* fl,
+  size_t numWords) {
+  FreeChunk *curr = fl->head();
+  size_t oldNumWords = curr->size();
+  assert(numWords >= MinChunkSize, "Word size is too small");
+  assert(curr != NULL, "List is empty");
+  assert(oldNumWords >= numWords + MinChunkSize,
+        "Size of chunks in the list is too small");
+
+  fl->removeChunk(curr);
+  // recorded indirectly by splitChunkAndReturnRemainder -
+  // smallSplit(oldNumWords, numWords);
+  FreeChunk* new_chunk = splitChunkAndReturnRemainder(curr, numWords);
+  // Does anything have to be done for the remainder in terms of
+  // fixing the card table?
+  assert(new_chunk == NULL || new_chunk->isFree(),
+    "Should be returning a free chunk");
+  return new_chunk;
+}
+
+FreeChunk*
+CompactibleFreeListSpace::splitChunkAndReturnRemainder(FreeChunk* chunk,
+  size_t new_size) {
+  assert_locked();
+  size_t size = chunk->size();
+  assert(size > new_size, "Split from a smaller block?");
+  assert(is_aligned(chunk), "alignment problem");
+  assert(size == adjustObjectSize(size), "alignment problem");
+  size_t rem_size = size - new_size;
+  assert(rem_size == adjustObjectSize(rem_size), "alignment problem");
+  assert(rem_size >= MinChunkSize, "Free chunk smaller than minimum");
+  FreeChunk* ffc = (FreeChunk*)((HeapWord*)chunk + new_size);
+  assert(is_aligned(ffc), "alignment problem");
+  ffc->setSize(rem_size);
+  ffc->linkNext(NULL);
+  ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads.
+  // Above must occur before BOT is updated below.
+  // adjust block offset table
+  _bt.split_block((HeapWord*)chunk, chunk->size(), new_size);
+  if (rem_size < SmallForDictionary) {
+    bool is_par = (SharedHeap::heap()->n_par_threads() > 0);
+    if (is_par) _indexedFreeListParLocks[rem_size]->lock();
+    returnChunkToFreeList(ffc);
+    split(size, rem_size);
+    if (is_par) _indexedFreeListParLocks[rem_size]->unlock();
+  } else {
+    returnChunkToDictionary(ffc);
+    split(size ,rem_size);
+  }
+  chunk->setSize(new_size);
+  return chunk;
+}
+
+void
+CompactibleFreeListSpace::sweep_completed() {
+  // Now that space is probably plentiful, refill linear
+  // allocation blocks as needed.
+  refillLinearAllocBlocksIfNeeded();
+}
+
+void
+CompactibleFreeListSpace::gc_prologue() {
+  assert_locked();
+  if (PrintFLSStatistics != 0) {
+    gclog_or_tty->print("Before GC:\n");
+    reportFreeListStatistics();
+  }
+  refillLinearAllocBlocksIfNeeded();
+}
+
+void
+CompactibleFreeListSpace::gc_epilogue() {
+  assert_locked();
+  if (PrintGCDetails && Verbose && !_adaptive_freelists) {
+    if (_smallLinearAllocBlock._word_size == 0)
+      warning("CompactibleFreeListSpace(epilogue):: Linear allocation failure");
+  }
+  assert(_promoInfo.noPromotions(), "_promoInfo inconsistency");
+  _promoInfo.stopTrackingPromotions();
+  repairLinearAllocationBlocks();
+  // Print Space's stats
+  if (PrintFLSStatistics != 0) {
+    gclog_or_tty->print("After GC:\n");
+    reportFreeListStatistics();
+  }
+}
+
+// Iteration support, mostly delegated from a CMS generation
+
+void CompactibleFreeListSpace::save_marks() {
+  // mark the "end" of the used space at the time of this call;
+  // note, however, that promoted objects from this point
+  // on are tracked in the _promoInfo below.
+  set_saved_mark_word(BlockOffsetArrayUseUnallocatedBlock ?
+                      unallocated_block() : end());
+  // inform allocator that promotions should be tracked.
+  assert(_promoInfo.noPromotions(), "_promoInfo inconsistency");
+  _promoInfo.startTrackingPromotions();
+}
+
+bool CompactibleFreeListSpace::no_allocs_since_save_marks() {
+  assert(_promoInfo.tracking(), "No preceding save_marks?");
+  guarantee(SharedHeap::heap()->n_par_threads() == 0,
+            "Shouldn't be called (yet) during parallel part of gc.");
+  return _promoInfo.noPromotions();
+}
+
+#define CFLS_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix)           \
+                                                                            \
+void CompactibleFreeListSpace::                                             \
+oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) {              \
+  assert(SharedHeap::heap()->n_par_threads() == 0,                          \
+         "Shouldn't be called (yet) during parallel part of gc.");          \
+  _promoInfo.promoted_oops_iterate##nv_suffix(blk);                         \
+  /*                                                                        \
+   * This also restores any displaced headers and removes the elements from \
+   * the iteration set as they are processed, so that we have a clean slate \
+   * at the end of the iteration. Note, thus, that if new objects are       \
+   * promoted as a result of the iteration they are iterated over as well.  \
+   */                                                                       \
+  assert(_promoInfo.noPromotions(), "_promoInfo inconsistency");            \
+}
+
+ALL_SINCE_SAVE_MARKS_CLOSURES(CFLS_OOP_SINCE_SAVE_MARKS_DEFN)
+
+//////////////////////////////////////////////////////////////////////////////
+// We go over the list of promoted objects, removing each from the list,
+// and applying the closure (this may, in turn, add more elements to
+// the tail of the promoted list, and these newly added objects will
+// also be processed) until the list is empty.
+// To aid verification and debugging, in the non-product builds
+// we actually forward _promoHead each time we process a promoted oop.
+// Note that this is not necessary in general (i.e. when we don't need to
+// call PromotionInfo::verify()) because oop_iterate can only add to the
+// end of _promoTail, and never needs to look at _promoHead.
+
+#define PROMOTED_OOPS_ITERATE_DEFN(OopClosureType, nv_suffix)               \
+                                                                            \
+void PromotionInfo::promoted_oops_iterate##nv_suffix(OopClosureType* cl) {  \
+  NOT_PRODUCT(verify());                                                    \
+  PromotedObject *curObj, *nextObj;                                         \
+  for (curObj = _promoHead; curObj != NULL; curObj = nextObj) {             \
+    if ((nextObj = curObj->next()) == NULL) {                               \
+      /* protect ourselves against additions due to closure application     \
+         below by resetting the list.  */                                   \
+      assert(_promoTail == curObj, "Should have been the tail");            \
+      _promoHead = _promoTail = NULL;                                       \
+    }                                                                       \
+    if (curObj->hasDisplacedMark()) {                                       \
+      /* restore displaced header */                                        \
+      oop(curObj)->set_mark(nextDisplacedHeader());                         \
+    } else {                                                                \
+      /* restore prototypical header */                                     \
+      oop(curObj)->init_mark();                                             \
+    }                                                                       \
+    /* The "promoted_mark" should now not be set */                         \
+    assert(!curObj->hasPromotedMark(),                                      \
+           "Should have been cleared by restoring displaced mark-word");    \
+    NOT_PRODUCT(_promoHead = nextObj);                                      \
+    if (cl != NULL) oop(curObj)->oop_iterate(cl);                           \
+    if (nextObj == NULL) { /* start at head of list reset above */          \
+      nextObj = _promoHead;                                                 \
+    }                                                                       \
+  }                                                                         \
+  assert(noPromotions(), "post-condition violation");                       \
+  assert(_promoHead == NULL && _promoTail == NULL, "emptied promoted list");\
+  assert(_spoolHead == _spoolTail, "emptied spooling buffers");             \
+  assert(_firstIndex == _nextIndex, "empty buffer");                        \
+}
+
+// This should have been ALL_SINCE_...() just like the others,
+// but, because the body of the method above is somehwat longer,
+// the MSVC compiler cannot cope; as a workaround, we split the
+// macro into its 3 constituent parts below (see original macro
+// definition in specializedOopClosures.hpp).
+SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES_YOUNG(PROMOTED_OOPS_ITERATE_DEFN)
+PROMOTED_OOPS_ITERATE_DEFN(OopsInGenClosure,_v)
+
+
+void CompactibleFreeListSpace::object_iterate_since_last_GC(ObjectClosure* cl) {
+  // ugghh... how would one do this efficiently for a non-contiguous space?
+  guarantee(false, "NYI");
+}
+
+bool CompactibleFreeListSpace::linearAllocationWouldFail() {
+  return _smallLinearAllocBlock._word_size == 0;
+}
+
+void CompactibleFreeListSpace::repairLinearAllocationBlocks() {
+  // Fix up linear allocation blocks to look like free blocks
+  repairLinearAllocBlock(&_smallLinearAllocBlock);
+}
+
+void CompactibleFreeListSpace::repairLinearAllocBlock(LinearAllocBlock* blk) {
+  assert_locked();
+  if (blk->_ptr != NULL) {
+    assert(blk->_word_size != 0 && blk->_word_size >= MinChunkSize,
+           "Minimum block size requirement");
+    FreeChunk* fc = (FreeChunk*)(blk->_ptr);
+    fc->setSize(blk->_word_size);
+    fc->linkPrev(NULL);   // mark as free
+    fc->dontCoalesce();
+    assert(fc->isFree(), "just marked it free");
+    assert(fc->cantCoalesce(), "just marked it uncoalescable");
+  }
+}
+
+void CompactibleFreeListSpace::refillLinearAllocBlocksIfNeeded() {
+  assert_locked();
+  if (_smallLinearAllocBlock._ptr == NULL) {
+    assert(_smallLinearAllocBlock._word_size == 0,
+      "Size of linAB should be zero if the ptr is NULL");
+    // Reset the linAB refill and allocation size limit.
+    _smallLinearAllocBlock.set(0, 0, 1024*SmallForLinearAlloc, SmallForLinearAlloc);
+  }
+  refillLinearAllocBlockIfNeeded(&_smallLinearAllocBlock);
+}
+
+void
+CompactibleFreeListSpace::refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk) {
+  assert_locked();
+  assert((blk->_ptr == NULL && blk->_word_size == 0) ||
+         (blk->_ptr != NULL && blk->_word_size >= MinChunkSize),
+         "blk invariant");
+  if (blk->_ptr == NULL) {
+    refillLinearAllocBlock(blk);
+  }
+  if (PrintMiscellaneous && Verbose) {
+    if (blk->_word_size == 0) {
+      warning("CompactibleFreeListSpace(prologue):: Linear allocation failure");
+    }
+  }
+}
+
+void
+CompactibleFreeListSpace::refillLinearAllocBlock(LinearAllocBlock* blk) {
+  assert_locked();
+  assert(blk->_word_size == 0 && blk->_ptr == NULL,
+         "linear allocation block should be empty");
+  FreeChunk* fc;
+  if (blk->_refillSize < SmallForDictionary &&
+      (fc = getChunkFromIndexedFreeList(blk->_refillSize)) != NULL) {
+    // A linAB's strategy might be to use small sizes to reduce
+    // fragmentation but still get the benefits of allocation from a
+    // linAB.
+  } else {
+    fc = getChunkFromDictionary(blk->_refillSize);
+  }
+  if (fc != NULL) {
+    blk->_ptr  = (HeapWord*)fc;
+    blk->_word_size = fc->size();
+    fc->dontCoalesce();   // to prevent sweeper from sweeping us up
+  }
+}
+
+// Support for compaction
+
+void CompactibleFreeListSpace::prepare_for_compaction(CompactPoint* cp) {
+  SCAN_AND_FORWARD(cp,end,block_is_obj,block_size);
+  // prepare_for_compaction() uses the space between live objects
+  // so that later phase can skip dead space quickly.  So verification
+  // of the free lists doesn't work after.
+}
+
+#define obj_size(q) adjustObjectSize(oop(q)->size())
+#define adjust_obj_size(s) adjustObjectSize(s)
+
+void CompactibleFreeListSpace::adjust_pointers() {
+  // In other versions of adjust_pointers(), a bail out
+  // based on the amount of live data in the generation
+  // (i.e., if 0, bail out) may be used.
+  // Cannot test used() == 0 here because the free lists have already
+  // been mangled by the compaction.
+
+  SCAN_AND_ADJUST_POINTERS(adjust_obj_size);
+  // See note about verification in prepare_for_compaction().
+}
+
+void CompactibleFreeListSpace::compact() {
+  SCAN_AND_COMPACT(obj_size);
+}
+
+// fragmentation_metric = 1 - [sum of (fbs**2) / (sum of fbs)**2]
+// where fbs is free block sizes
+double CompactibleFreeListSpace::flsFrag() const {
+  size_t itabFree = totalSizeInIndexedFreeLists();
+  double frag = 0.0;
+  size_t i;
+
+  for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    double sz  = i;
+    frag      += _indexedFreeList[i].count() * (sz * sz);
+  }
+
+  double totFree = itabFree +
+                   _dictionary->totalChunkSize(DEBUG_ONLY(freelistLock()));
+  if (totFree > 0) {
+    frag = ((frag + _dictionary->sum_of_squared_block_sizes()) /
+            (totFree * totFree));
+    frag = (double)1.0  - frag;
+  } else {
+    assert(frag == 0.0, "Follows from totFree == 0");
+  }
+  return frag;
+}
+
+#define CoalSurplusPercent 1.05
+#define SplitSurplusPercent 1.10
+
+void CompactibleFreeListSpace::beginSweepFLCensus(
+  float inter_sweep_current,
+  float inter_sweep_estimate) {
+  assert_locked();
+  size_t i;
+  for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    FreeList* fl    = &_indexedFreeList[i];
+    fl->compute_desired(inter_sweep_current, inter_sweep_estimate);
+    fl->set_coalDesired((ssize_t)((double)fl->desired() * CoalSurplusPercent));
+    fl->set_beforeSweep(fl->count());
+    fl->set_bfrSurp(fl->surplus());
+  }
+  _dictionary->beginSweepDictCensus(CoalSurplusPercent,
+                                    inter_sweep_current,
+                                    inter_sweep_estimate);
+}
+
+void CompactibleFreeListSpace::setFLSurplus() {
+  assert_locked();
+  size_t i;
+  for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    FreeList *fl = &_indexedFreeList[i];
+    fl->set_surplus(fl->count() -
+                    (ssize_t)((double)fl->desired() * SplitSurplusPercent));
+  }
+}
+
+void CompactibleFreeListSpace::setFLHints() {
+  assert_locked();
+  size_t i;
+  size_t h = IndexSetSize;
+  for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) {
+    FreeList *fl = &_indexedFreeList[i];
+    fl->set_hint(h);
+    if (fl->surplus() > 0) {
+      h = i;
+    }
+  }
+}
+
+void CompactibleFreeListSpace::clearFLCensus() {
+  assert_locked();
+  int i;
+  for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    FreeList *fl = &_indexedFreeList[i];
+    fl->set_prevSweep(fl->count());
+    fl->set_coalBirths(0);
+    fl->set_coalDeaths(0);
+    fl->set_splitBirths(0);
+    fl->set_splitDeaths(0);
+  }
+}
+
+void CompactibleFreeListSpace::endSweepFLCensus(int sweepCt) {
+  setFLSurplus();
+  setFLHints();
+  if (PrintGC && PrintFLSCensus > 0) {
+    printFLCensus(sweepCt);
+  }
+  clearFLCensus();
+  assert_locked();
+  _dictionary->endSweepDictCensus(SplitSurplusPercent);
+}
+
+bool CompactibleFreeListSpace::coalOverPopulated(size_t size) {
+  if (size < SmallForDictionary) {
+    FreeList *fl = &_indexedFreeList[size];
+    return (fl->coalDesired() < 0) ||
+           ((int)fl->count() > fl->coalDesired());
+  } else {
+    return dictionary()->coalDictOverPopulated(size);
+  }
+}
+
+void CompactibleFreeListSpace::smallCoalBirth(size_t size) {
+  assert(size < SmallForDictionary, "Size too large for indexed list");
+  FreeList *fl = &_indexedFreeList[size];
+  fl->increment_coalBirths();
+  fl->increment_surplus();
+}
+
+void CompactibleFreeListSpace::smallCoalDeath(size_t size) {
+  assert(size < SmallForDictionary, "Size too large for indexed list");
+  FreeList *fl = &_indexedFreeList[size];
+  fl->increment_coalDeaths();
+  fl->decrement_surplus();
+}
+
+void CompactibleFreeListSpace::coalBirth(size_t size) {
+  if (size  < SmallForDictionary) {
+    smallCoalBirth(size);
+  } else {
+    dictionary()->dictCensusUpdate(size,
+                                   false /* split */,
+                                   true /* birth */);
+  }
+}
+
+void CompactibleFreeListSpace::coalDeath(size_t size) {
+  if(size  < SmallForDictionary) {
+    smallCoalDeath(size);
+  } else {
+    dictionary()->dictCensusUpdate(size,
+                                   false /* split */,
+                                   false /* birth */);
+  }
+}
+
+void CompactibleFreeListSpace::smallSplitBirth(size_t size) {
+  assert(size < SmallForDictionary, "Size too large for indexed list");
+  FreeList *fl = &_indexedFreeList[size];
+  fl->increment_splitBirths();
+  fl->increment_surplus();
+}
+
+void CompactibleFreeListSpace::smallSplitDeath(size_t size) {
+  assert(size < SmallForDictionary, "Size too large for indexed list");
+  FreeList *fl = &_indexedFreeList[size];
+  fl->increment_splitDeaths();
+  fl->decrement_surplus();
+}
+
+void CompactibleFreeListSpace::splitBirth(size_t size) {
+  if (size  < SmallForDictionary) {
+    smallSplitBirth(size);
+  } else {
+    dictionary()->dictCensusUpdate(size,
+                                   true /* split */,
+                                   true /* birth */);
+  }
+}
+
+void CompactibleFreeListSpace::splitDeath(size_t size) {
+  if (size  < SmallForDictionary) {
+    smallSplitDeath(size);
+  } else {
+    dictionary()->dictCensusUpdate(size,
+                                   true /* split */,
+                                   false /* birth */);
+  }
+}
+
+void CompactibleFreeListSpace::split(size_t from, size_t to1) {
+  size_t to2 = from - to1;
+  splitDeath(from);
+  splitBirth(to1);
+  splitBirth(to2);
+}
+
+
+void CompactibleFreeListSpace::print() const {
+  tty->print(" CompactibleFreeListSpace");
+  Space::print();
+}
+
+void CompactibleFreeListSpace::prepare_for_verify() {
+  assert_locked();
+  repairLinearAllocationBlocks();
+  // Verify that the SpoolBlocks look like free blocks of
+  // appropriate sizes... To be done ...
+}
+
+class VerifyAllBlksClosure: public BlkClosure {
+  const CompactibleFreeListSpace* _sp;
+  const MemRegion                 _span;
+
+ public:
+  VerifyAllBlksClosure(const CompactibleFreeListSpace* sp,
+    MemRegion span) :  _sp(sp), _span(span) { }
+
+  size_t do_blk(HeapWord* addr) {
+    size_t res;
+    if (_sp->block_is_obj(addr)) {
+      oop p = oop(addr);
+      guarantee(p->is_oop(), "Should be an oop");
+      res = _sp->adjustObjectSize(p->size());
+      if (_sp->obj_is_alive(addr)) {
+        p->verify();
+      }
+    } else {
+      FreeChunk* fc = (FreeChunk*)addr;
+      res = fc->size();
+      if (FLSVerifyLists && !fc->cantCoalesce()) {
+        guarantee(_sp->verifyChunkInFreeLists(fc),
+                  "Chunk should be on a free list");
+      }
+    }
+    guarantee(res != 0, "Livelock: no rank reduction!");
+    return res;
+  }
+};
+
+class VerifyAllOopsClosure: public OopClosure {
+  const CMSCollector*             _collector;
+  const CompactibleFreeListSpace* _sp;
+  const MemRegion                 _span;
+  const bool                      _past_remark;
+  const CMSBitMap*                _bit_map;
+
+ public:
+  VerifyAllOopsClosure(const CMSCollector* collector,
+    const CompactibleFreeListSpace* sp, MemRegion span,
+    bool past_remark, CMSBitMap* bit_map) :
+    OopClosure(), _collector(collector), _sp(sp), _span(span),
+    _past_remark(past_remark), _bit_map(bit_map) { }
+
+  void do_oop(oop* ptr) {
+    oop p = *ptr;
+    if (p != NULL) {
+      if (_span.contains(p)) { // the interior oop points into CMS heap
+        if (!_span.contains(ptr)) { // reference from outside CMS heap
+          // Should be a valid object; the first disjunct below allows
+          // us to sidestep an assertion in block_is_obj() that insists
+          // that p be in _sp. Note that several generations (and spaces)
+          // are spanned by _span (CMS heap) above.
+          guarantee(!_sp->is_in_reserved(p) || _sp->block_is_obj((HeapWord*)p),
+                    "Should be an object");
+          guarantee(p->is_oop(), "Should be an oop");
+          p->verify();
+          if (_past_remark) {
+            // Remark has been completed, the object should be marked
+            _bit_map->isMarked((HeapWord*)p);
+          }
+        }
+        else { // reference within CMS heap
+          if (_past_remark) {
+            // Remark has been completed -- so the referent should have
+            // been marked, if referring object is.
+            if (_bit_map->isMarked(_collector->block_start(ptr))) {
+              guarantee(_bit_map->isMarked((HeapWord*)p), "Marking error?");
+            }
+          }
+        }
+      } else if (_sp->is_in_reserved(ptr)) {
+        // the reference is from FLS, and points out of FLS
+        guarantee(p->is_oop(), "Should be an oop");
+        p->verify();
+      }
+    }
+  }
+};
+
+void CompactibleFreeListSpace::verify(bool ignored) const {
+  assert_lock_strong(&_freelistLock);
+  verify_objects_initialized();
+  MemRegion span = _collector->_span;
+  bool past_remark = (_collector->abstract_state() ==
+                      CMSCollector::Sweeping);
+
+  ResourceMark rm;
+  HandleMark  hm;
+
+  // Check integrity of CFL data structures
+  _promoInfo.verify();
+  _dictionary->verify();
+  if (FLSVerifyIndexTable) {
+    verifyIndexedFreeLists();
+  }
+  // Check integrity of all objects and free blocks in space
+  {
+    VerifyAllBlksClosure cl(this, span);
+    ((CompactibleFreeListSpace*)this)->blk_iterate(&cl);  // cast off const
+  }
+  // Check that all references in the heap to FLS
+  // are to valid objects in FLS or that references in
+  // FLS are to valid objects elsewhere in the heap
+  if (FLSVerifyAllHeapReferences)
+  {
+    VerifyAllOopsClosure cl(_collector, this, span, past_remark,
+      _collector->markBitMap());
+    CollectedHeap* ch = Universe::heap();
+    ch->oop_iterate(&cl);              // all oops in generations
+    ch->permanent_oop_iterate(&cl);    // all oops in perm gen
+  }
+
+  if (VerifyObjectStartArray) {
+    // Verify the block offset table
+    _bt.verify();
+  }
+}
+
+#ifndef PRODUCT
+void CompactibleFreeListSpace::verifyFreeLists() const {
+  if (FLSVerifyLists) {
+    _dictionary->verify();
+    verifyIndexedFreeLists();
+  } else {
+    if (FLSVerifyDictionary) {
+      _dictionary->verify();
+    }
+    if (FLSVerifyIndexTable) {
+      verifyIndexedFreeLists();
+    }
+  }
+}
+#endif
+
+void CompactibleFreeListSpace::verifyIndexedFreeLists() const {
+  size_t i = 0;
+  for (; i < MinChunkSize; i++) {
+    guarantee(_indexedFreeList[i].head() == NULL, "should be NULL");
+  }
+  for (; i < IndexSetSize; i++) {
+    verifyIndexedFreeList(i);
+  }
+}
+
+void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const {
+  guarantee(size % 2 == 0, "Odd slots should be empty");
+  for (FreeChunk* fc = _indexedFreeList[size].head(); fc != NULL;
+    fc = fc->next()) {
+    guarantee(fc->size() == size, "Size inconsistency");
+    guarantee(fc->isFree(), "!free?");
+    guarantee(fc->next() == NULL || fc->next()->prev() == fc, "Broken list");
+  }
+}
+
+#ifndef PRODUCT
+void CompactibleFreeListSpace::checkFreeListConsistency() const {
+  assert(_dictionary->minSize() <= IndexSetSize,
+    "Some sizes can't be allocated without recourse to"
+    " linear allocation buffers");
+  assert(MIN_TREE_CHUNK_SIZE*HeapWordSize == sizeof(TreeChunk),
+    "else MIN_TREE_CHUNK_SIZE is wrong");
+  assert((IndexSetStride == 2 && IndexSetStart == 2) ||
+         (IndexSetStride == 1 && IndexSetStart == 1), "just checking");
+  assert((IndexSetStride != 2) || (MinChunkSize % 2 == 0),
+      "Some for-loops may be incorrectly initialized");
+  assert((IndexSetStride != 2) || (IndexSetSize % 2 == 1),
+      "For-loops that iterate over IndexSet with stride 2 may be wrong");
+}
+#endif
+
+void CompactibleFreeListSpace::printFLCensus(int sweepCt) const {
+  assert_lock_strong(&_freelistLock);
+  ssize_t bfrSurp     = 0;
+  ssize_t surplus     = 0;
+  ssize_t desired     = 0;
+  ssize_t prevSweep   = 0;
+  ssize_t beforeSweep = 0;
+  ssize_t count       = 0;
+  ssize_t coalBirths  = 0;
+  ssize_t coalDeaths  = 0;
+  ssize_t splitBirths = 0;
+  ssize_t splitDeaths = 0;
+  gclog_or_tty->print("end sweep# %d\n", sweepCt);
+  gclog_or_tty->print("%4s\t"    "%7s\t"      "%7s\t"      "%7s\t"      "%7s\t"
+             "%7s\t"    "%7s\t"      "%7s\t"      "%7s\t"      "%7s\t"
+             "%7s\t"    "\n",
+             "size",    "bfrsurp",   "surplus",   "desired",   "prvSwep",
+             "bfrSwep", "count",     "cBirths",   "cDeaths",   "sBirths",
+             "sDeaths");
+
+  size_t totalFree = 0;
+  for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+    const FreeList *fl = &_indexedFreeList[i];
+        totalFree += fl->count() * fl->size();
+
+    gclog_or_tty->print("%4d\t"          "%7d\t"             "%7d\t"        "%7d\t"
+               "%7d\t"          "%7d\t"             "%7d\t"        "%7d\t"
+               "%7d\t"          "%7d\t"             "%7d\t"        "\n",
+               fl->size(),       fl->bfrSurp(),     fl->surplus(), fl->desired(),
+               fl->prevSweep(),  fl->beforeSweep(), fl->count(),   fl->coalBirths(),
+               fl->coalDeaths(), fl->splitBirths(), fl->splitDeaths());
+    bfrSurp     += fl->bfrSurp();
+    surplus     += fl->surplus();
+    desired     += fl->desired();
+    prevSweep   += fl->prevSweep();
+    beforeSweep += fl->beforeSweep();
+    count       += fl->count();
+    coalBirths  += fl->coalBirths();
+    coalDeaths  += fl->coalDeaths();
+    splitBirths += fl->splitBirths();
+    splitDeaths += fl->splitDeaths();
+  }
+  gclog_or_tty->print("%4s\t"
+            "%7d\t"      "%7d\t"     "%7d\t"        "%7d\t"       "%7d\t"
+            "%7d\t"      "%7d\t"     "%7d\t"        "%7d\t"       "%7d\t" "\n",
+            "totl",
+            bfrSurp,     surplus,     desired,     prevSweep,     beforeSweep,
+            count,       coalBirths,  coalDeaths,  splitBirths,   splitDeaths);
+  gclog_or_tty->print_cr("Total free in indexed lists %d words", totalFree);
+  gclog_or_tty->print("growth: %8.5f  deficit: %8.5f\n",
+    (double)(splitBirths+coalBirths-splitDeaths-coalDeaths)/
+            (prevSweep != 0 ? (double)prevSweep : 1.0),
+    (double)(desired - count)/(desired != 0 ? (double)desired : 1.0));
+  _dictionary->printDictCensus();
+}
+
+// Return the next displaced header, incrementing the pointer and
+// recycling spool area as necessary.
+markOop PromotionInfo::nextDisplacedHeader() {
+  assert(_spoolHead != NULL, "promotionInfo inconsistency");
+  assert(_spoolHead != _spoolTail || _firstIndex < _nextIndex,
+         "Empty spool space: no displaced header can be fetched");
+  assert(_spoolHead->bufferSize > _firstIndex, "Off by one error at head?");
+  markOop hdr = _spoolHead->displacedHdr[_firstIndex];
+  // Spool forward
+  if (++_firstIndex == _spoolHead->bufferSize) { // last location in this block
+    // forward to next block, recycling this block into spare spool buffer
+    SpoolBlock* tmp = _spoolHead->nextSpoolBlock;
+    assert(_spoolHead != _spoolTail, "Spooling storage mix-up");
+    _spoolHead->nextSpoolBlock = _spareSpool;
+    _spareSpool = _spoolHead;
+    _spoolHead = tmp;
+    _firstIndex = 1;
+    NOT_PRODUCT(
+      if (_spoolHead == NULL) {  // all buffers fully consumed
+        assert(_spoolTail == NULL && _nextIndex == 1,
+               "spool buffers processing inconsistency");
+      }
+    )
+  }
+  return hdr;
+}
+
+void PromotionInfo::track(PromotedObject* trackOop) {
+  track(trackOop, oop(trackOop)->klass());
+}
+
+void PromotionInfo::track(PromotedObject* trackOop, klassOop klassOfOop) {
+  // make a copy of header as it may need to be spooled
+  markOop mark = oop(trackOop)->mark();
+  trackOop->clearNext();
+  if (mark->must_be_preserved_for_cms_scavenge(klassOfOop)) {
+    // save non-prototypical header, and mark oop
+    saveDisplacedHeader(mark);
+    trackOop->setDisplacedMark();
+  } else {
+    // we'd like to assert something like the following:
+    // assert(mark == markOopDesc::prototype(), "consistency check");
+    // ... but the above won't work because the age bits have not (yet) been
+    // cleared. The remainder of the check would be identical to the
+    // condition checked in must_be_preserved() above, so we don't really
+    // have anything useful to check here!
+  }
+  if (_promoTail != NULL) {
+    assert(_promoHead != NULL, "List consistency");
+    _promoTail->setNext(trackOop);
+    _promoTail = trackOop;
+  } else {
+    assert(_promoHead == NULL, "List consistency");
+    _promoHead = _promoTail = trackOop;
+  }
+  // Mask as newly promoted, so we can skip over such objects
+  // when scanning dirty cards
+  assert(!trackOop->hasPromotedMark(), "Should not have been marked");
+  trackOop->setPromotedMark();
+}
+
+// Save the given displaced header, incrementing the pointer and
+// obtaining more spool area as necessary.
+void PromotionInfo::saveDisplacedHeader(markOop hdr) {
+  assert(_spoolHead != NULL && _spoolTail != NULL,
+         "promotionInfo inconsistency");
+  assert(_spoolTail->bufferSize > _nextIndex, "Off by one error at tail?");
+  _spoolTail->displacedHdr[_nextIndex] = hdr;
+  // Spool forward
+  if (++_nextIndex == _spoolTail->bufferSize) { // last location in this block
+    // get a new spooling block
+    assert(_spoolTail->nextSpoolBlock == NULL, "tail should terminate spool list");
+    _splice_point = _spoolTail;                   // save for splicing
+    _spoolTail->nextSpoolBlock = getSpoolBlock(); // might fail
+    _spoolTail = _spoolTail->nextSpoolBlock;      // might become NULL ...
+    // ... but will attempt filling before next promotion attempt
+    _nextIndex = 1;
+  }
+}
+
+// Ensure that spooling space exists. Return false if spooling space
+// could not be obtained.
+bool PromotionInfo::ensure_spooling_space_work() {
+  assert(!has_spooling_space(), "Only call when there is no spooling space");
+  // Try and obtain more spooling space
+  SpoolBlock* newSpool = getSpoolBlock();
+  assert(newSpool == NULL ||
+         (newSpool->bufferSize != 0 && newSpool->nextSpoolBlock == NULL),
+        "getSpoolBlock() sanity check");
+  if (newSpool == NULL) {
+    return false;
+  }
+  _nextIndex = 1;
+  if (_spoolTail == NULL) {
+    _spoolTail = newSpool;
+    if (_spoolHead == NULL) {
+      _spoolHead = newSpool;
+      _firstIndex = 1;
+    } else {
+      assert(_splice_point != NULL && _splice_point->nextSpoolBlock == NULL,
+             "Splice point invariant");
+      // Extra check that _splice_point is connected to list
+      #ifdef ASSERT
+      {
+        SpoolBlock* blk = _spoolHead;
+        for (; blk->nextSpoolBlock != NULL;
+             blk = blk->nextSpoolBlock);
+        assert(blk != NULL && blk == _splice_point,
+               "Splice point incorrect");
+      }
+      #endif // ASSERT
+      _splice_point->nextSpoolBlock = newSpool;
+    }
+  } else {
+    assert(_spoolHead != NULL, "spool list consistency");
+    _spoolTail->nextSpoolBlock = newSpool;
+    _spoolTail = newSpool;
+  }
+  return true;
+}
+
+// Get a free spool buffer from the free pool, getting a new block
+// from the heap if necessary.
+SpoolBlock* PromotionInfo::getSpoolBlock() {
+  SpoolBlock* res;
+  if ((res = _spareSpool) != NULL) {
+    _spareSpool = _spareSpool->nextSpoolBlock;
+    res->nextSpoolBlock = NULL;
+  } else {  // spare spool exhausted, get some from heap
+    res = (SpoolBlock*)(space()->allocateScratch(refillSize()));
+    if (res != NULL) {
+      res->init();
+    }
+  }
+  assert(res == NULL || res->nextSpoolBlock == NULL, "postcondition");
+  return res;
+}
+
+void PromotionInfo::startTrackingPromotions() {
+  assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex,
+         "spooling inconsistency?");
+  _firstIndex = _nextIndex = 1;
+  _tracking = true;
+}
+
+void PromotionInfo::stopTrackingPromotions() {
+  assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex,
+         "spooling inconsistency?");
+  _firstIndex = _nextIndex = 1;
+  _tracking = false;
+}
+
+// When _spoolTail is not NULL, then the slot <_spoolTail, _nextIndex>
+// points to the next slot available for filling.
+// The set of slots holding displaced headers are then all those in the
+// right-open interval denoted by:
+//
+//    [ <_spoolHead, _firstIndex>, <_spoolTail, _nextIndex> )
+//
+// When _spoolTail is NULL, then the set of slots with displaced headers
+// is all those starting at the slot <_spoolHead, _firstIndex> and
+// going up to the last slot of last block in the linked list.
+// In this lartter case, _splice_point points to the tail block of
+// this linked list of blocks holding displaced headers.
+void PromotionInfo::verify() const {
+  // Verify the following:
+  // 1. the number of displaced headers matches the number of promoted
+  //    objects that have displaced headers
+  // 2. each promoted object lies in this space
+  debug_only(
+    PromotedObject* junk = NULL;
+    assert(junk->next_addr() == (void*)(oop(junk)->mark_addr()),
+           "Offset of PromotedObject::_next is expected to align with "
+           "  the OopDesc::_mark within OopDesc");
+  )
+  // FIXME: guarantee????
+  guarantee(_spoolHead == NULL || _spoolTail != NULL ||
+            _splice_point != NULL, "list consistency");
+  guarantee(_promoHead == NULL || _promoTail != NULL, "list consistency");
+  // count the number of objects with displaced headers
+  size_t numObjsWithDisplacedHdrs = 0;
+  for (PromotedObject* curObj = _promoHead; curObj != NULL; curObj = curObj->next()) {
+    guarantee(space()->is_in_reserved((HeapWord*)curObj), "Containment");
+    // the last promoted object may fail the mark() != NULL test of is_oop().
+    guarantee(curObj->next() == NULL || oop(curObj)->is_oop(), "must be an oop");
+    if (curObj->hasDisplacedMark()) {
+      numObjsWithDisplacedHdrs++;
+    }
+  }
+  // Count the number of displaced headers
+  size_t numDisplacedHdrs = 0;
+  for (SpoolBlock* curSpool = _spoolHead;
+       curSpool != _spoolTail && curSpool != NULL;
+       curSpool = curSpool->nextSpoolBlock) {
+    // the first entry is just a self-pointer; indices 1 through
+    // bufferSize - 1 are occupied (thus, bufferSize - 1 slots).
+    guarantee((void*)curSpool->displacedHdr == (void*)&curSpool->displacedHdr,
+              "first entry of displacedHdr should be self-referential");
+    numDisplacedHdrs += curSpool->bufferSize - 1;
+  }
+  guarantee((_spoolHead == _spoolTail) == (numDisplacedHdrs == 0),
+            "internal consistency");
+  guarantee(_spoolTail != NULL || _nextIndex == 1,
+            "Inconsistency between _spoolTail and _nextIndex");
+  // We overcounted (_firstIndex-1) worth of slots in block
+  // _spoolHead and we undercounted (_nextIndex-1) worth of
+  // slots in block _spoolTail. We make an appropriate
+  // adjustment by subtracting the first and adding the
+  // second:  - (_firstIndex - 1) + (_nextIndex - 1)
+  numDisplacedHdrs += (_nextIndex - _firstIndex);
+  guarantee(numDisplacedHdrs == numObjsWithDisplacedHdrs, "Displaced hdr count");
+}
+
+
+CFLS_LAB::CFLS_LAB(CompactibleFreeListSpace* cfls) :
+  _cfls(cfls)
+{
+  _blocks_to_claim = CMSParPromoteBlocksToClaim;
+  for (size_t i = CompactibleFreeListSpace::IndexSetStart;
+       i < CompactibleFreeListSpace::IndexSetSize;
+       i += CompactibleFreeListSpace::IndexSetStride) {
+    _indexedFreeList[i].set_size(i);
+  }
+}
+
+HeapWord* CFLS_LAB::alloc(size_t word_sz) {
+  FreeChunk* res;
+  word_sz = _cfls->adjustObjectSize(word_sz);
+  if (word_sz >=  CompactibleFreeListSpace::IndexSetSize) {
+    // This locking manages sync with other large object allocations.
+    MutexLockerEx x(_cfls->parDictionaryAllocLock(),
+                    Mutex::_no_safepoint_check_flag);
+    res = _cfls->getChunkFromDictionaryExact(word_sz);
+    if (res == NULL) return NULL;
+  } else {
+    FreeList* fl = &_indexedFreeList[word_sz];
+    bool filled = false; //TRAP
+    if (fl->count() == 0) {
+      bool filled = true; //TRAP
+      // Attempt to refill this local free list.
+      _cfls->par_get_chunk_of_blocks(word_sz, _blocks_to_claim, fl);
+      // If it didn't work, give up.
+      if (fl->count() == 0) return NULL;
+    }
+    res = fl->getChunkAtHead();
+    assert(res != NULL, "Why was count non-zero?");
+  }
+  res->markNotFree();
+  assert(!res->isFree(), "shouldn't be marked free");
+  assert(oop(res)->klass() == NULL, "should look uninitialized");
+  // mangle a just allocated object with a distinct pattern.
+  debug_only(res->mangleAllocated(word_sz));
+  return (HeapWord*)res;
+}
+
+void CFLS_LAB::retire() {
+  for (size_t i = CompactibleFreeListSpace::IndexSetStart;
+       i < CompactibleFreeListSpace::IndexSetSize;
+       i += CompactibleFreeListSpace::IndexSetStride) {
+    if (_indexedFreeList[i].count() > 0) {
+      MutexLockerEx x(_cfls->_indexedFreeListParLocks[i],
+                      Mutex::_no_safepoint_check_flag);
+      _cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]);
+      // Reset this list.
+      _indexedFreeList[i] = FreeList();
+      _indexedFreeList[i].set_size(i);
+    }
+  }
+}
+
+void
+CompactibleFreeListSpace::
+par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList* fl) {
+  assert(fl->count() == 0, "Precondition.");
+  assert(word_sz < CompactibleFreeListSpace::IndexSetSize,
+         "Precondition");
+
+  // We'll try all multiples of word_sz in the indexed set (starting with
+  // word_sz itself), then try getting a big chunk and splitting it.
+  int k = 1;
+  size_t cur_sz = k * word_sz;
+  bool found = false;
+  while (cur_sz < CompactibleFreeListSpace::IndexSetSize && k == 1) {
+    FreeList* gfl = &_indexedFreeList[cur_sz];
+    FreeList fl_for_cur_sz;  // Empty.
+    fl_for_cur_sz.set_size(cur_sz);
+    {
+      MutexLockerEx x(_indexedFreeListParLocks[cur_sz],
+                      Mutex::_no_safepoint_check_flag);
+      if (gfl->count() != 0) {
+        size_t nn = MAX2(n/k, (size_t)1);
+        gfl->getFirstNChunksFromList(nn, &fl_for_cur_sz);
+        found = true;
+      }
+    }
+    // Now transfer fl_for_cur_sz to fl.  Common case, we hope, is k = 1.
+    if (found) {
+      if (k == 1) {
+        fl->prepend(&fl_for_cur_sz);
+      } else {
+        // Divide each block on fl_for_cur_sz up k ways.
+        FreeChunk* fc;
+        while ((fc = fl_for_cur_sz.getChunkAtHead()) != NULL) {
+          // Must do this in reverse order, so that anybody attempting to
+          // access the main chunk sees it as a single free block until we
+          // change it.
+          size_t fc_size = fc->size();
+          for (int i = k-1; i >= 0; i--) {
+            FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz);
+            ffc->setSize(word_sz);
+            ffc->linkNext(NULL);
+            ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads.
+            // Above must occur before BOT is updated below.
+            // splitting from the right, fc_size == (k - i + 1) * wordsize
+            _bt.mark_block((HeapWord*)ffc, word_sz);
+            fc_size -= word_sz;
+            _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size());
+            _bt.verify_single_block((HeapWord*)fc, fc_size);
+            _bt.verify_single_block((HeapWord*)ffc, ffc->size());
+            // Push this on "fl".
+            fl->returnChunkAtHead(ffc);
+          }
+          // TRAP
+          assert(fl->tail()->next() == NULL, "List invariant.");
+        }
+      }
+      return;
+    }
+    k++; cur_sz = k * word_sz;
+  }
+  // Otherwise, we'll split a block from the dictionary.
+  FreeChunk* fc = NULL;
+  FreeChunk* rem_fc = NULL;
+  size_t rem;
+  {
+    MutexLockerEx x(parDictionaryAllocLock(),
+                    Mutex::_no_safepoint_check_flag);
+    while (n > 0) {
+      fc = dictionary()->getChunk(MAX2(n * word_sz,
+                                  _dictionary->minSize()),
+                                  FreeBlockDictionary::atLeast);
+      if (fc != NULL) {
+        _bt.allocated((HeapWord*)fc, fc->size());  // update _unallocated_blk
+        dictionary()->dictCensusUpdate(fc->size(),
+                                       true /*split*/,
+                                       false /*birth*/);
+        break;
+      } else {
+        n--;
+      }
+    }
+    if (fc == NULL) return;
+    // Otherwise, split up that block.
+    size_t nn = fc->size() / word_sz;
+    n = MIN2(nn, n);
+    rem = fc->size() - n * word_sz;
+    // If there is a remainder, and it's too small, allocate one fewer.
+    if (rem > 0 && rem < MinChunkSize) {
+      n--; rem += word_sz;
+    }
+    // First return the remainder, if any.
+    // Note that we hold the lock until we decide if we're going to give
+    // back the remainder to the dictionary, since a contending allocator
+    // may otherwise see the heap as empty.  (We're willing to take that
+    // hit if the block is a small block.)
+    if (rem > 0) {
+      size_t prefix_size = n * word_sz;
+      rem_fc = (FreeChunk*)((HeapWord*)fc + prefix_size);
+      rem_fc->setSize(rem);
+      rem_fc->linkNext(NULL);
+      rem_fc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads.
+      // Above must occur before BOT is updated below.
+      _bt.split_block((HeapWord*)fc, fc->size(), prefix_size);
+      if (rem >= IndexSetSize) {
+        returnChunkToDictionary(rem_fc);
+        dictionary()->dictCensusUpdate(fc->size(),
+                                       true /*split*/,
+                                       true /*birth*/);
+        rem_fc = NULL;
+      }
+      // Otherwise, return it to the small list below.
+    }
+  }
+  //
+  if (rem_fc != NULL) {
+    MutexLockerEx x(_indexedFreeListParLocks[rem],
+                    Mutex::_no_safepoint_check_flag);
+    _bt.verify_not_unallocated((HeapWord*)rem_fc, rem_fc->size());
+    _indexedFreeList[rem].returnChunkAtHead(rem_fc);
+    smallSplitBirth(rem);
+  }
+
+  // Now do the splitting up.
+  // Must do this in reverse order, so that anybody attempting to
+  // access the main chunk sees it as a single free block until we
+  // change it.
+  size_t fc_size = n * word_sz;
+  // All but first chunk in this loop
+  for (ssize_t i = n-1; i > 0; i--) {
+    FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz);
+    ffc->setSize(word_sz);
+    ffc->linkNext(NULL);
+    ffc->linkPrev(NULL); // Mark as a free block for other (parallel) GC threads.
+    // Above must occur before BOT is updated below.
+    // splitting from the right, fc_size == (n - i + 1) * wordsize
+    _bt.mark_block((HeapWord*)ffc, word_sz);
+    fc_size -= word_sz;
+    _bt.verify_not_unallocated((HeapWord*)ffc, ffc->size());
+    _bt.verify_single_block((HeapWord*)ffc, ffc->size());
+    _bt.verify_single_block((HeapWord*)fc, fc_size);
+    // Push this on "fl".
+    fl->returnChunkAtHead(ffc);
+  }
+  // First chunk
+  fc->setSize(word_sz);
+  fc->linkNext(NULL);
+  fc->linkPrev(NULL);
+  _bt.verify_not_unallocated((HeapWord*)fc, fc->size());
+  _bt.verify_single_block((HeapWord*)fc, fc->size());
+  fl->returnChunkAtHead(fc);
+
+  {
+    MutexLockerEx x(_indexedFreeListParLocks[word_sz],
+                    Mutex::_no_safepoint_check_flag);
+    ssize_t new_births = _indexedFreeList[word_sz].splitBirths() + n;
+    _indexedFreeList[word_sz].set_splitBirths(new_births);
+    ssize_t new_surplus = _indexedFreeList[word_sz].surplus() + n;
+    _indexedFreeList[word_sz].set_surplus(new_surplus);
+  }
+
+  // TRAP
+  assert(fl->tail()->next() == NULL, "List invariant.");
+}
+
+// Set up the space's par_seq_tasks structure for work claiming
+// for parallel rescan. See CMSParRemarkTask where this is currently used.
+// XXX Need to suitably abstract and generalize this and the next
+// method into one.
+void
+CompactibleFreeListSpace::
+initialize_sequential_subtasks_for_rescan(int n_threads) {
+  // The "size" of each task is fixed according to rescan_task_size.
+  assert(n_threads > 0, "Unexpected n_threads argument");
+  const size_t task_size = rescan_task_size();
+  size_t n_tasks = (used_region().word_size() + task_size - 1)/task_size;
+  assert((used_region().start() + (n_tasks - 1)*task_size <
+          used_region().end()) &&
+         (used_region().start() + n_tasks*task_size >=
+          used_region().end()), "n_task calculation incorrect");
+  SequentialSubTasksDone* pst = conc_par_seq_tasks();
+  assert(!pst->valid(), "Clobbering existing data?");
+  pst->set_par_threads(n_threads);
+  pst->set_n_tasks((int)n_tasks);
+}
+
+// Set up the space's par_seq_tasks structure for work claiming
+// for parallel concurrent marking. See CMSConcMarkTask where this is currently used.
+void
+CompactibleFreeListSpace::
+initialize_sequential_subtasks_for_marking(int n_threads,
+                                           HeapWord* low) {
+  // The "size" of each task is fixed according to rescan_task_size.
+  assert(n_threads > 0, "Unexpected n_threads argument");
+  const size_t task_size = marking_task_size();
+  assert(task_size > CardTableModRefBS::card_size_in_words &&
+         (task_size %  CardTableModRefBS::card_size_in_words == 0),
+         "Otherwise arithmetic below would be incorrect");
+  MemRegion span = _gen->reserved();
+  if (low != NULL) {
+    if (span.contains(low)) {
+      // Align low down to  a card boundary so that
+      // we can use block_offset_careful() on span boundaries.
+      HeapWord* aligned_low = (HeapWord*)align_size_down((uintptr_t)low,
+                                 CardTableModRefBS::card_size);
+      // Clip span prefix at aligned_low
+      span = span.intersection(MemRegion(aligned_low, span.end()));
+    } else if (low > span.end()) {
+      span = MemRegion(low, low);  // Null region
+    } // else use entire span
+  }
+  assert(span.is_empty() ||
+         ((uintptr_t)span.start() %  CardTableModRefBS::card_size == 0),
+        "span should start at a card boundary");
+  size_t n_tasks = (span.word_size() + task_size - 1)/task_size;
+  assert((n_tasks == 0) == span.is_empty(), "Inconsistency");
+  assert(n_tasks == 0 ||
+         ((span.start() + (n_tasks - 1)*task_size < span.end()) &&
+          (span.start() + n_tasks*task_size >= span.end())),
+         "n_task calculation incorrect");
+  SequentialSubTasksDone* pst = conc_par_seq_tasks();
+  assert(!pst->valid(), "Clobbering existing data?");
+  pst->set_par_threads(n_threads);
+  pst->set_n_tasks((int)n_tasks);
+}