7045397: NPG: Add freelists to class loader arenas.

Reviewed-by: coleenp, stefank, jprovino, ohair

make/excludeSrc.make

@@ -79,10 +79,10 @@ ifeq ($(INCLUDE_ALTERNATE_GCS), false)
       CXXFLAGS += -DSERIALGC
       CFLAGS += -DSERIALGC
       Src_Files_EXCLUDE += \
-	binaryTreeDictionary.cpp cmsAdaptiveSizePolicy.cpp cmsCollectorPolicy.cpp \
+	cmsAdaptiveSizePolicy.cpp cmsCollectorPolicy.cpp \
 	cmsGCAdaptivePolicyCounters.cpp cmsLockVerifier.cpp cmsPermGen.cpp compactibleFreeListSpace.cpp \
-	concurrentMarkSweepGeneration.cpp concurrentMarkSweepThread.cpp freeBlockDictionary.cpp \
-	freeChunk.cpp freeList.cpp promotionInfo.cpp vmCMSOperations.cpp collectionSetChooser.cpp \
+	concurrentMarkSweepGeneration.cpp concurrentMarkSweepThread.cpp \
+	freeChunk.cpp adaptiveFreeList.cpp promotionInfo.cpp vmCMSOperations.cpp collectionSetChooser.cpp \
 	concurrentG1Refine.cpp concurrentG1RefineThread.cpp concurrentMark.cpp concurrentMarkThread.cpp \
 	dirtyCardQueue.cpp g1AllocRegion.cpp g1BlockOffsetTable.cpp g1CollectedHeap.cpp g1GCPhaseTimes.cpp \
 	g1CollectorPolicy.cpp g1ErgoVerbose.cpp g1_globals.cpp g1HRPrinter.cpp g1MarkSweep.cpp \

src/share/vm/gc_implementation/concurrentMarkSweep/adaptiveFreeList.cpp

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc_implementation/concurrentMarkSweep/adaptiveFreeList.hpp"
+#include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
+#include "memory/freeBlockDictionary.hpp"
+#include "memory/sharedHeap.hpp"
+#include "runtime/globals.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/vmThread.hpp"
+
+template <>
+void AdaptiveFreeList<FreeChunk>::print_on(outputStream* st, const char* c) const {
+  if (c != NULL) {
+    st->print("%16s", c);
+  } else {
+    st->print(SIZE_FORMAT_W(16), size());
+  }
+  st->print("\t"
+           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t"
+           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\n",
+           bfr_surp(),             surplus(),             desired(),             prev_sweep(),           before_sweep(),
+           count(),               coal_births(),          coal_deaths(),          split_births(),         split_deaths());
+}
+
+template <class Chunk>
+AdaptiveFreeList<Chunk>::AdaptiveFreeList() : FreeList<Chunk>(), _hint(0) {
+  init_statistics();
+}
+
+template <class Chunk>
+AdaptiveFreeList<Chunk>::AdaptiveFreeList(Chunk* fc) : FreeList<Chunk>(fc), _hint(0) {
+  init_statistics();
+#ifndef PRODUCT
+  _allocation_stats.set_returned_bytes(size() * HeapWordSize);
+#endif
+}
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::initialize() {
+  FreeList<Chunk>::initialize();
+  set_hint(0);
+  init_statistics(true /* split_birth */);
+}
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::reset(size_t hint) {
+  FreeList<Chunk>::reset();
+  set_hint(hint);
+}
+
+#ifndef PRODUCT
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::assert_proper_lock_protection_work() const {
+  assert(protecting_lock() != NULL, "Don't call this directly");
+  assert(ParallelGCThreads > 0, "Don't call this directly");
+  Thread* thr = Thread::current();
+  if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) {
+    // assert that we are holding the freelist lock
+  } else if (thr->is_GC_task_thread()) {
+    assert(protecting_lock()->owned_by_self(), "FreeList RACE DETECTED");
+  } else if (thr->is_Java_thread()) {
+    assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing");
+  } else {
+    ShouldNotReachHere();  // unaccounted thread type?
+  }
+}
+#endif
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::init_statistics(bool split_birth) {
+  _allocation_stats.initialize(split_birth);
+}
+
+template <class Chunk>
+size_t AdaptiveFreeList<Chunk>::get_better_size() {
+
+  // A candidate chunk has been found.  If it is already under
+  // populated and there is a hinT, REturn the hint().  Else
+  // return the size of this chunk.
+  if (surplus() <= 0) {
+    if (hint() != 0) {
+      return hint();
+    } else {
+      return size();
+    }
+  } else {
+    // This list has a surplus so use it.
+    return size();
+  }
+}
+
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::return_chunk_at_head(Chunk* chunk) {
+  assert_proper_lock_protection();
+  return_chunk_at_head(chunk, true);
+}
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::return_chunk_at_head(Chunk* chunk, bool record_return) {
+  FreeList<Chunk>::return_chunk_at_head(chunk, record_return);
+#ifdef ASSERT
+  if (record_return) {
+    increment_returned_bytes_by(size()*HeapWordSize);
+  }
+#endif
+}
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::return_chunk_at_tail(Chunk* chunk) {
+  return_chunk_at_tail(chunk, true);
+}
+
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::return_chunk_at_tail(Chunk* chunk, bool record_return) {
+  FreeList<Chunk>::return_chunk_at_tail(chunk, record_return);
+#ifdef ASSERT
+  if (record_return) {
+    increment_returned_bytes_by(size()*HeapWordSize);
+  }
+#endif
+}
+
+#ifndef PRODUCT
+template <class Chunk>
+void AdaptiveFreeList<Chunk>::verify_stats() const {
+  // The +1 of the LH comparand is to allow some "looseness" in
+  // checking: we usually call this interface when adding a block
+  // and we'll subsequently update the stats; we cannot update the
+  // stats beforehand because in the case of the large-block BT
+  // dictionary for example, this might be the first block and
+  // in that case there would be no place that we could record
+  // the stats (which are kept in the block itself).
+  assert((_allocation_stats.prev_sweep() + _allocation_stats.split_births()
+          + _allocation_stats.coal_births() + 1)   // Total Production Stock + 1
+         >= (_allocation_stats.split_deaths() + _allocation_stats.coal_deaths()
+             + (ssize_t)count()),                // Total Current Stock + depletion
+         err_msg("FreeList " PTR_FORMAT " of size " SIZE_FORMAT
+                 " violates Conservation Principle: "
+                 "prev_sweep(" SIZE_FORMAT ")"
+                 " + split_births(" SIZE_FORMAT ")"
+                 " + coal_births(" SIZE_FORMAT ") + 1 >= "
+                 " split_deaths(" SIZE_FORMAT ")"
+                 " coal_deaths(" SIZE_FORMAT ")"
+                 " + count(" SSIZE_FORMAT ")",
+                 this, size(), _allocation_stats.prev_sweep(), _allocation_stats.split_births(),
+                 _allocation_stats.split_births(), _allocation_stats.split_deaths(),
+                 _allocation_stats.coal_deaths(), count()));
+}
+#endif
+
+// Needs to be after the definitions have been seen.
+template class AdaptiveFreeList<FreeChunk>;

src/share/vm/gc_implementation/concurrentMarkSweep/adaptiveFreeList.hpp

+/*
+ * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_MEMORY_ADAPTIVEFREELIST_HPP
+#define SHARE_VM_MEMORY_ADAPTIVEFREELIST_HPP
+
+#include "memory/freeList.hpp"
+#include "gc_implementation/shared/allocationStats.hpp"
+
+class CompactibleFreeListSpace;
+
+// A class for maintaining a free list of Chunk's.  The FreeList
+// maintains a the structure of the list (head, tail, etc.) plus
+// statistics for allocations from the list.  The links between items
+// are not part of FreeList.  The statistics are
+// used to make decisions about coalescing Chunk's when they
+// are swept during collection.
+//
+// See the corresponding .cpp file for a description of the specifics
+// for that implementation.
+
+class Mutex;
+
+template <class Chunk>
+class AdaptiveFreeList : public FreeList<Chunk> {
+  friend class CompactibleFreeListSpace;
+  friend class VMStructs;
+  // friend class PrintTreeCensusClosure<Chunk, FreeList_t>;
+
+  size_t        _hint;          // next larger size list with a positive surplus
+
+  AllocationStats _allocation_stats; // allocation-related statistics
+
+ public:
+
+  AdaptiveFreeList();
+  AdaptiveFreeList(Chunk* fc);
+
+  using FreeList<Chunk>::assert_proper_lock_protection;
+#ifdef ASSERT
+  using FreeList<Chunk>::protecting_lock;
+#endif
+  using FreeList<Chunk>::count;
+  using FreeList<Chunk>::size;
+  using FreeList<Chunk>::verify_chunk_in_free_list;
+  using FreeList<Chunk>::getFirstNChunksFromList;
+  using FreeList<Chunk>::print_on;
+  void return_chunk_at_head(Chunk* fc, bool record_return);
+  void return_chunk_at_head(Chunk* fc);
+  void return_chunk_at_tail(Chunk* fc, bool record_return);
+  void return_chunk_at_tail(Chunk* fc);
+  using FreeList<Chunk>::return_chunk_at_tail;
+  using FreeList<Chunk>::remove_chunk;
+  using FreeList<Chunk>::prepend;
+  using FreeList<Chunk>::print_labels_on;
+  using FreeList<Chunk>::get_chunk_at_head;
+
+  // Initialize.
+  void initialize();
+
+  // Reset the head, tail, hint, and count of a free list.
+  void reset(size_t hint);
+
+  void assert_proper_lock_protection_work() const PRODUCT_RETURN;
+
+  void print_on(outputStream* st, const char* c = NULL) const;
+
+  size_t hint() const {
+    return _hint;
+  }
+  void set_hint(size_t v) {
+    assert_proper_lock_protection();
+    assert(v == 0 || size() < v, "Bad hint");
+    _hint = v;
+  }
+
+  size_t get_better_size();
+
+  // Accessors for statistics
+  void init_statistics(bool split_birth = false);
+
+  AllocationStats* allocation_stats() {
+    assert_proper_lock_protection();
+    return &_allocation_stats;
+  }
+
+  ssize_t desired() const {
+    return _allocation_stats.desired();
+  }
+  void set_desired(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_desired(v);
+  }
+  void compute_desired(float inter_sweep_current,
+                       float inter_sweep_estimate,
+                       float intra_sweep_estimate) {
+    assert_proper_lock_protection();
+    _allocation_stats.compute_desired(count(),
+                                      inter_sweep_current,
+                                      inter_sweep_estimate,
+                                      intra_sweep_estimate);
+  }
+  ssize_t coal_desired() const {
+    return _allocation_stats.coal_desired();
+  }
+  void set_coal_desired(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_coal_desired(v);
+  }
+
+  ssize_t surplus() const {
+    return _allocation_stats.surplus();
+  }
+  void set_surplus(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_surplus(v);
+  }
+  void increment_surplus() {
+    assert_proper_lock_protection();
+    _allocation_stats.increment_surplus();
+  }
+  void decrement_surplus() {
+    assert_proper_lock_protection();
+    _allocation_stats.decrement_surplus();
+  }
+
+  ssize_t bfr_surp() const {
+    return _allocation_stats.bfr_surp();
+  }
+  void set_bfr_surp(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_bfr_surp(v);
+  }
+  ssize_t prev_sweep() const {
+    return _allocation_stats.prev_sweep();
+  }
+  void set_prev_sweep(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_prev_sweep(v);
+  }
+  ssize_t before_sweep() const {
+    return _allocation_stats.before_sweep();
+  }
+  void set_before_sweep(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_before_sweep(v);
+  }
+
+  ssize_t coal_births() const {
+    return _allocation_stats.coal_births();
+  }
+  void set_coal_births(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_coal_births(v);
+  }
+  void increment_coal_births() {
+    assert_proper_lock_protection();
+    _allocation_stats.increment_coal_births();
+  }
+
+  ssize_t coal_deaths() const {
+    return _allocation_stats.coal_deaths();
+  }
+  void set_coal_deaths(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_coal_deaths(v);
+  }
+  void increment_coal_deaths() {
+    assert_proper_lock_protection();
+    _allocation_stats.increment_coal_deaths();
+  }
+
+  ssize_t split_births() const {
+    return _allocation_stats.split_births();
+  }
+  void set_split_births(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_split_births(v);
+  }
+  void increment_split_births() {
+    assert_proper_lock_protection();
+    _allocation_stats.increment_split_births();
+  }
+
+  ssize_t split_deaths() const {
+    return _allocation_stats.split_deaths();
+  }
+  void set_split_deaths(ssize_t v) {
+    assert_proper_lock_protection();
+    _allocation_stats.set_split_deaths(v);
+  }
+  void increment_split_deaths() {
+    assert_proper_lock_protection();
+    _allocation_stats.increment_split_deaths();
+  }
+
+#ifndef PRODUCT
+  // For debugging.  The "_returned_bytes" in all the lists are summed
+  // and compared with the total number of bytes swept during a
+  // collection.
+  size_t returned_bytes() const { return _allocation_stats.returned_bytes(); }
+  void set_returned_bytes(size_t v) { _allocation_stats.set_returned_bytes(v); }
+  void increment_returned_bytes_by(size_t v) {
+    _allocation_stats.set_returned_bytes(_allocation_stats.returned_bytes() + v);
+  }
+  // Stats verification
+  void verify_stats() const;
+#endif  // NOT PRODUCT
+};
+
+#endif // SHARE_VM_MEMORY_ADAPTIVEFREELIST_HPP

src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp

@@ -91,7 +91,7 @@ CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs,
   _collector(NULL)
 {
   assert(sizeof(FreeChunk) / BytesPerWord <= MinChunkSize,
-    "FreeChunk is larger than expected");
+         "FreeChunk is larger than expected");
   _bt.set_space(this);
   initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle);
   // We have all of "mr", all of which we place in the dictionary
@@ -101,14 +101,14 @@ CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs,
   // implementation, namely, the simple binary tree (splaying
   // temporarily disabled).
   switch (dictionaryChoice) {
+    case FreeBlockDictionary<FreeChunk>::dictionaryBinaryTree:
+      _dictionary = new BinaryTreeDictionary<FreeChunk, AdaptiveFreeList>(mr);
+      break;
     case FreeBlockDictionary<FreeChunk>::dictionarySplayTree:
     case FreeBlockDictionary<FreeChunk>::dictionarySkipList:
     default:
       warning("dictionaryChoice: selected option not understood; using"
               " default BinaryTreeDictionary implementation instead.");
-    case FreeBlockDictionary<FreeChunk>::dictionaryBinaryTree:
-      _dictionary = new BinaryTreeDictionary<FreeChunk>(mr, use_adaptive_freelists);
-      break;
   }
   assert(_dictionary != NULL, "CMS dictionary initialization");
   // The indexed free lists are initially all empty and are lazily
@@ -453,7 +453,7 @@ const {
   reportIndexedFreeListStatistics();
   gclog_or_tty->print_cr("Layout of Indexed Freelists");
   gclog_or_tty->print_cr("---------------------------");
-  FreeList<FreeChunk>::print_labels_on(st, "size");
+  AdaptiveFreeList<FreeChunk>::print_labels_on(st, "size");
   for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
     _indexedFreeList[i].print_on(gclog_or_tty);
     for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;
@@ -1319,7 +1319,7 @@ FreeChunk* CompactibleFreeListSpace::getChunkFromGreater(size_t numWords) {
   size_t currSize = numWords + MinChunkSize;
   assert(currSize % MinObjAlignment == 0, "currSize should be aligned");
   for (i = currSize; i < IndexSetSize; i += IndexSetStride) {
-    FreeList<FreeChunk>* fl = &_indexedFreeList[i];
+    AdaptiveFreeList<FreeChunk>* fl = &_indexedFreeList[i];
     if (fl->head()) {
       ret = getFromListGreater(fl, numWords);
       assert(ret == NULL || ret->is_free(), "Should be returning a free chunk");
@@ -1702,7 +1702,9 @@ CompactibleFreeListSpace::returnChunkToDictionary(FreeChunk* chunk) {
   _dictionary->return_chunk(chunk);
 #ifndef PRODUCT
   if (CMSCollector::abstract_state() != CMSCollector::Sweeping) {
-    TreeChunk<FreeChunk>::as_TreeChunk(chunk)->list()->verify_stats();
+    TreeChunk<FreeChunk, AdaptiveFreeList>* tc = TreeChunk<FreeChunk, AdaptiveFreeList>::as_TreeChunk(chunk);
+    TreeList<FreeChunk, AdaptiveFreeList>* tl = tc->list();
+    tl->verify_stats();
   }
 #endif // PRODUCT
 }
@@ -1745,7 +1747,7 @@ CompactibleFreeListSpace::addChunkToFreeListsAtEndRecordingStats(
   {
     MutexLockerEx x(lock, Mutex::_no_safepoint_check_flag);
     ec = dictionary()->find_largest_dict();  // get largest block
-    if (ec != NULL && ec->end() == chunk) {
+    if (ec != NULL && ec->end() == (uintptr_t*) chunk) {
       // It's a coterminal block - we can coalesce.
       size_t old_size = ec->size();
       coalDeath(old_size);
@@ -1850,11 +1852,11 @@ FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) {
      the excess is >= MIN_CHUNK. */
   size_t start = align_object_size(numWords + MinChunkSize);
   if (start < IndexSetSize) {
-    FreeList<FreeChunk>* it   = _indexedFreeList;
+    AdaptiveFreeList<FreeChunk>* it   = _indexedFreeList;
     size_t    hint = _indexedFreeList[start].hint();
     while (hint < IndexSetSize) {
       assert(hint % MinObjAlignment == 0, "hint should be aligned");
-      FreeList<FreeChunk> *fl = &_indexedFreeList[hint];
+      AdaptiveFreeList<FreeChunk> *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.
@@ -1873,7 +1875,7 @@ FreeChunk* CompactibleFreeListSpace::bestFitSmall(size_t numWords) {
 }
 
 /* Requires fl->size >= numWords + MinChunkSize */
-FreeChunk* CompactibleFreeListSpace::getFromListGreater(FreeList<FreeChunk>* fl,
+FreeChunk* CompactibleFreeListSpace::getFromListGreater(AdaptiveFreeList<FreeChunk>* fl,
   size_t numWords) {
   FreeChunk *curr = fl->head();
   size_t oldNumWords = curr->size();
@@ -2155,7 +2157,7 @@ void CompactibleFreeListSpace::beginSweepFLCensus(
   assert_locked();
   size_t i;
   for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
-    FreeList<FreeChunk>* fl = &_indexedFreeList[i];
+    AdaptiveFreeList<FreeChunk>* fl    = &_indexedFreeList[i];
     if (PrintFLSStatistics > 1) {
       gclog_or_tty->print("size[%d] : ", i);
     }
@@ -2174,7 +2176,7 @@ void CompactibleFreeListSpace::setFLSurplus() {
   assert_locked();
   size_t i;
   for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
-    FreeList<FreeChunk> *fl = &_indexedFreeList[i];
+    AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
     fl->set_surplus(fl->count() -
                     (ssize_t)((double)fl->desired() * CMSSmallSplitSurplusPercent));
   }
@@ -2185,7 +2187,7 @@ void CompactibleFreeListSpace::setFLHints() {
   size_t i;
   size_t h = IndexSetSize;
   for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) {
-    FreeList<FreeChunk> *fl = &_indexedFreeList[i];
+    AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
     fl->set_hint(h);
     if (fl->surplus() > 0) {
       h = i;
@@ -2197,7 +2199,7 @@ void CompactibleFreeListSpace::clearFLCensus() {
   assert_locked();
   size_t i;
   for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
-    FreeList<FreeChunk> *fl = &_indexedFreeList[i];
+    AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
     fl->set_prev_sweep(fl->count());
     fl->set_coal_births(0);
     fl->set_coal_deaths(0);
@@ -2224,7 +2226,7 @@ void CompactibleFreeListSpace::endSweepFLCensus(size_t sweep_count) {
 
 bool CompactibleFreeListSpace::coalOverPopulated(size_t size) {
   if (size < SmallForDictionary) {
-    FreeList<FreeChunk> *fl = &_indexedFreeList[size];
+    AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
     return (fl->coal_desired() < 0) ||
            ((int)fl->count() > fl->coal_desired());
   } else {
@@ -2234,14 +2236,14 @@ bool CompactibleFreeListSpace::coalOverPopulated(size_t size) {
 
 void CompactibleFreeListSpace::smallCoalBirth(size_t size) {
   assert(size < SmallForDictionary, "Size too large for indexed list");
-  FreeList<FreeChunk> *fl = &_indexedFreeList[size];
+  AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
   fl->increment_coal_births();
   fl->increment_surplus();
 }
 
 void CompactibleFreeListSpace::smallCoalDeath(size_t size) {
   assert(size < SmallForDictionary, "Size too large for indexed list");
-  FreeList<FreeChunk> *fl = &_indexedFreeList[size];
+  AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
   fl->increment_coal_deaths();
   fl->decrement_surplus();
 }
@@ -2250,7 +2252,7 @@ void CompactibleFreeListSpace::coalBirth(size_t size) {
   if (size  < SmallForDictionary) {
     smallCoalBirth(size);
   } else {
-    dictionary()->dict_census_udpate(size,
+    dictionary()->dict_census_update(size,
                                    false /* split */,
                                    true /* birth */);
   }
@@ -2260,7 +2262,7 @@ void CompactibleFreeListSpace::coalDeath(size_t size) {
   if(size  < SmallForDictionary) {
     smallCoalDeath(size);
   } else {
-    dictionary()->dict_census_udpate(size,
+    dictionary()->dict_census_update(size,
                                    false /* split */,
                                    false /* birth */);
   }
@@ -2268,14 +2270,14 @@ void CompactibleFreeListSpace::coalDeath(size_t size) {
 
 void CompactibleFreeListSpace::smallSplitBirth(size_t size) {
   assert(size < SmallForDictionary, "Size too large for indexed list");
-  FreeList<FreeChunk> *fl = &_indexedFreeList[size];
+  AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
   fl->increment_split_births();
   fl->increment_surplus();
 }
 
 void CompactibleFreeListSpace::smallSplitDeath(size_t size) {
   assert(size < SmallForDictionary, "Size too large for indexed list");
-  FreeList<FreeChunk> *fl = &_indexedFreeList[size];
+  AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
   fl->increment_split_deaths();
   fl->decrement_surplus();
 }
@@ -2284,7 +2286,7 @@ void CompactibleFreeListSpace::split_birth(size_t size) {
   if (size  < SmallForDictionary) {
     smallSplitBirth(size);
   } else {
-    dictionary()->dict_census_udpate(size,
+    dictionary()->dict_census_update(size,
                                    true /* split */,
                                    true /* birth */);
   }
@@ -2294,7 +2296,7 @@ void CompactibleFreeListSpace::splitDeath(size_t size) {
   if (size  < SmallForDictionary) {
     smallSplitDeath(size);
   } else {
-    dictionary()->dict_census_udpate(size,
+    dictionary()->dict_census_update(size,
                                    true /* split */,
                                    false /* birth */);
   }
@@ -2517,10 +2519,10 @@ void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const {
 
 #ifndef PRODUCT
 void CompactibleFreeListSpace::check_free_list_consistency() const {
-  assert(_dictionary->min_size() <= IndexSetSize,
+  assert((TreeChunk<FreeChunk, AdaptiveFreeList>::min_size() <= IndexSetSize),
     "Some sizes can't be allocated without recourse to"
     " linear allocation buffers");
-  assert(BinaryTreeDictionary<FreeChunk>::min_tree_chunk_size*HeapWordSize == sizeof(TreeChunk<FreeChunk>),
+  assert((TreeChunk<FreeChunk, AdaptiveFreeList>::min_size()*HeapWordSize == sizeof(TreeChunk<FreeChunk, AdaptiveFreeList>)),
     "else MIN_TREE_CHUNK_SIZE is wrong");
   assert(IndexSetStart != 0, "IndexSetStart not initialized");
   assert(IndexSetStride != 0, "IndexSetStride not initialized");
@@ -2529,15 +2531,15 @@ void CompactibleFreeListSpace::check_free_list_consistency() const {
 
 void CompactibleFreeListSpace::printFLCensus(size_t sweep_count) const {
   assert_lock_strong(&_freelistLock);
-  FreeList<FreeChunk> total;
+  AdaptiveFreeList<FreeChunk> total;
   gclog_or_tty->print("end sweep# " SIZE_FORMAT "\n", sweep_count);
-  FreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
+  AdaptiveFreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
   size_t total_free = 0;
   for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
-    const FreeList<FreeChunk> *fl = &_indexedFreeList[i];
+    const AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
     total_free += fl->count() * fl->size();
     if (i % (40*IndexSetStride) == 0) {
-      FreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
+      AdaptiveFreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
     }
     fl->print_on(gclog_or_tty);
     total.set_bfr_surp(    total.bfr_surp()     + fl->bfr_surp()    );
@@ -2620,7 +2622,7 @@ HeapWord* CFLS_LAB::alloc(size_t word_sz) {
     res = _cfls->getChunkFromDictionaryExact(word_sz);
     if (res == NULL) return NULL;
   } else {
-    FreeList<FreeChunk>* fl = &_indexedFreeList[word_sz];
+    AdaptiveFreeList<FreeChunk>* fl = &_indexedFreeList[word_sz];
     if (fl->count() == 0) {
       // Attempt to refill this local free list.
       get_from_global_pool(word_sz, fl);
@@ -2640,7 +2642,7 @@ HeapWord* CFLS_LAB::alloc(size_t word_sz) {
 
 // Get a chunk of blocks of the right size and update related
 // book-keeping stats
-void CFLS_LAB::get_from_global_pool(size_t word_sz, FreeList<FreeChunk>* fl) {
+void CFLS_LAB::get_from_global_pool(size_t word_sz, AdaptiveFreeList<FreeChunk>* fl) {
   // Get the #blocks we want to claim
   size_t n_blks = (size_t)_blocks_to_claim[word_sz].average();
   assert(n_blks > 0, "Error");
@@ -2722,7 +2724,7 @@ void CFLS_LAB::retire(int tid) {
         if (num_retire > 0) {
           _cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]);
           // Reset this list.
-          _indexedFreeList[i] = FreeList<FreeChunk>();
+          _indexedFreeList[i] = AdaptiveFreeList<FreeChunk>();
           _indexedFreeList[i].set_size(i);
         }
       }
@@ -2736,7 +2738,7 @@ void CFLS_LAB::retire(int tid) {
   }
 }
 
-void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList<FreeChunk>* fl) {
+void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl) {
   assert(fl->count() == 0, "Precondition.");
   assert(word_sz < CompactibleFreeListSpace::IndexSetSize,
          "Precondition");
@@ -2752,12 +2754,12 @@ void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n
          (cur_sz < CompactibleFreeListSpace::IndexSetSize) &&
          (CMSSplitIndexedFreeListBlocks || k <= 1);
          k++, cur_sz = k * word_sz) {
-      FreeList<FreeChunk> fl_for_cur_sz;  // Empty.
+      AdaptiveFreeList<FreeChunk> fl_for_cur_sz;  // Empty.
       fl_for_cur_sz.set_size(cur_sz);
       {
         MutexLockerEx x(_indexedFreeListParLocks[cur_sz],
                         Mutex::_no_safepoint_check_flag);
-        FreeList<FreeChunk>* gfl = &_indexedFreeList[cur_sz];
+        AdaptiveFreeList<FreeChunk>* gfl = &_indexedFreeList[cur_sz];
         if (gfl->count() != 0) {
           // nn is the number of chunks of size cur_sz that
           // we'd need to split k-ways each, in order to create
@@ -2832,12 +2834,11 @@ void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n
     MutexLockerEx x(parDictionaryAllocLock(),
                     Mutex::_no_safepoint_check_flag);
     while (n > 0) {
-      fc = dictionary()->get_chunk(MAX2(n * word_sz,
-                                  _dictionary->min_size()),
+      fc = dictionary()->get_chunk(MAX2(n * word_sz, _dictionary->min_size()),
                                   FreeBlockDictionary<FreeChunk>::atLeast);
       if (fc != NULL) {
         _bt.allocated((HeapWord*)fc, fc->size(), true /* reducing */);  // update _unallocated_blk
-        dictionary()->dict_census_udpate(fc->size(),
+        dictionary()->dict_census_update(fc->size(),
                                        true /*split*/,
                                        false /*birth*/);
         break;
@@ -2890,7 +2891,7 @@ void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n
       fc->set_size(prefix_size);
       if (rem >= IndexSetSize) {
         returnChunkToDictionary(rem_fc);
-        dictionary()->dict_census_udpate(rem, true /*split*/, true /*birth*/);
+        dictionary()->dict_census_update(rem, true /*split*/, true /*birth*/);
         rem_fc = NULL;
       }
       // Otherwise, return it to the small list below.

src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp

@@ -25,6 +25,7 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_COMPACTIBLEFREELISTSPACE_HPP
 
+#include "gc_implementation/concurrentMarkSweep/adaptiveFreeList.hpp"
 #include "gc_implementation/concurrentMarkSweep/promotionInfo.hpp"
 #include "memory/binaryTreeDictionary.hpp"
 #include "memory/blockOffsetTable.inline.hpp"
@@ -38,6 +39,7 @@
 class CompactibleFreeListSpace;
 class BlkClosure;
 class BlkClosureCareful;
+class FreeChunk;
 class UpwardsObjectClosure;
 class ObjectClosureCareful;
 class Klass;
@@ -131,7 +133,7 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   FreeBlockDictionary<FreeChunk>::DictionaryChoice _dictionaryChoice;
   FreeBlockDictionary<FreeChunk>* _dictionary;    // ptr to dictionary for large size blocks
 
-  FreeList<FreeChunk> _indexedFreeList[IndexSetSize];
+  AdaptiveFreeList<FreeChunk> _indexedFreeList[IndexSetSize];
                                        // indexed array for small size blocks
   // allocation stategy
   bool       _fitStrategy;      // Use best fit strategy.
@@ -168,7 +170,7 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   // If the count of "fl" is negative, it's absolute value indicates a
   // number of free chunks that had been previously "borrowed" from global
   // list of size "word_sz", and must now be decremented.
-  void par_get_chunk_of_blocks(size_t word_sz, size_t n, FreeList<FreeChunk>* fl);
+  void par_get_chunk_of_blocks(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl);
 
   // Allocation helper functions
   // Allocate using a strategy that takes from the indexed free lists
@@ -214,7 +216,7 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   // and return it.  The split off remainder is returned to
   // the free lists.  The old name for getFromListGreater
   // was lookInListGreater.
-  FreeChunk* getFromListGreater(FreeList<FreeChunk>* fl, size_t numWords);
+  FreeChunk* getFromListGreater(AdaptiveFreeList<FreeChunk>* fl, size_t numWords);
   // Get a chunk in the indexed free list or dictionary,
   // by considering a larger chunk and splitting it.
   FreeChunk* getChunkFromGreater(size_t numWords);
@@ -621,7 +623,7 @@ class CFLS_LAB : public CHeapObj<mtGC> {
   CompactibleFreeListSpace* _cfls;
 
   // Our local free lists.
-  FreeList<FreeChunk> _indexedFreeList[CompactibleFreeListSpace::IndexSetSize];
+  AdaptiveFreeList<FreeChunk> _indexedFreeList[CompactibleFreeListSpace::IndexSetSize];
 
   // Initialized from a command-line arg.
 
@@ -634,7 +636,7 @@ class CFLS_LAB : public CHeapObj<mtGC> {
   size_t        _num_blocks        [CompactibleFreeListSpace::IndexSetSize];
 
   // Internal work method
-  void get_from_global_pool(size_t word_sz, FreeList<FreeChunk>* fl);
+  void get_from_global_pool(size_t word_sz, AdaptiveFreeList<FreeChunk>* fl);
 
 public:
   CFLS_LAB(CompactibleFreeListSpace* cfls);

src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp

@@ -9143,7 +9143,7 @@ void ASConcurrentMarkSweepGeneration::shrink_by(size_t desired_bytes) {
     size_t shrinkable_size_in_bytes = chunk_at_end->size();
     size_t aligned_shrinkable_size_in_bytes =
       align_size_down(shrinkable_size_in_bytes, os::vm_page_size());
-    assert(unallocated_start <= chunk_at_end->end(),
+    assert(unallocated_start <= (HeapWord*) chunk_at_end->end(),
       "Inconsistent chunk at end of space");
     size_t bytes = MIN2(desired_bytes, aligned_shrinkable_size_in_bytes);
     size_t word_size_before = heap_word_size(_virtual_space.committed_size());
@@ -9210,7 +9210,7 @@ void ASConcurrentMarkSweepGeneration::shrink_by(size_t desired_bytes) {
 
     assert(_cmsSpace->unallocated_block() <= _cmsSpace->end(),
       "Inconsistency at end of space");
-    assert(chunk_at_end->end() == _cmsSpace->end(),
+    assert(chunk_at_end->end() == (uintptr_t*) _cmsSpace->end(),
       "Shrinking is inconsistent");
     return;
   }

src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.hpp

@@ -133,7 +133,7 @@ class FreeChunk VALUE_OBJ_CLASS_SPEC {
   }
 
   // Return the address past the end of this chunk
-  HeapWord* end() const { return ((HeapWord*) this) + size(); }
+  uintptr_t* end() const { return ((uintptr_t*) this) + size(); }
 
   // debugging
   void verify()             const PRODUCT_RETURN;

src/share/vm/gc_implementation/concurrentMarkSweep/vmStructs_cms.hpp

@@ -25,6 +25,8 @@
 #ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_VMSTRUCTS_CMS_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_VMSTRUCTS_CMS_HPP
 
+typedef BinaryTreeDictionary<FreeChunk, AdaptiveFreeList> AFLBinaryTreeDictionary;
+
 #define VM_STRUCTS_CMS(nonstatic_field, \
                    volatile_nonstatic_field, \
                    static_field) \
@@ -38,14 +40,8 @@
   nonstatic_field(CMSCollector,                _markBitMap,                                   CMSBitMap)                             \
   nonstatic_field(ConcurrentMarkSweepGeneration, _cmsSpace,                                   CompactibleFreeListSpace*)             \
      static_field(ConcurrentMarkSweepThread,   _collector,                                    CMSCollector*)                         \
-  volatile_nonstatic_field(FreeChunk,          _size,                                         size_t)                                \
-  nonstatic_field(FreeChunk,                   _next,                                         FreeChunk*)                            \
-  nonstatic_field(FreeChunk,                   _prev,                                         FreeChunk*)                            \
   nonstatic_field(LinearAllocBlock,            _word_size,                                    size_t)                                \
-  nonstatic_field(FreeList<FreeChunk>,         _size,                                         size_t)                                \
-  nonstatic_field(FreeList<FreeChunk>,         _count,                                        ssize_t)                               \
-  nonstatic_field(BinaryTreeDictionary<FreeChunk>,_total_size,                                 size_t)                                \
-  nonstatic_field(CompactibleFreeListSpace,    _dictionary,                                   FreeBlockDictionary<FreeChunk>*)       \
+  nonstatic_field(AFLBinaryTreeDictionary,     _total_size,                                   size_t)                                \
   nonstatic_field(CompactibleFreeListSpace,    _indexedFreeList[0],                           FreeList<FreeChunk>)                   \
   nonstatic_field(CompactibleFreeListSpace,    _smallLinearAllocBlock,                        LinearAllocBlock)
 
@@ -60,19 +56,17 @@
   declare_toplevel_type(CMSCollector)                                     \
   declare_toplevel_type(CMSBitMap)                                        \
   declare_toplevel_type(FreeChunk)                                        \
+  declare_toplevel_type(Metablock)                                        \
   declare_toplevel_type(ConcurrentMarkSweepThread*)                       \
   declare_toplevel_type(ConcurrentMarkSweepGeneration*)                   \
   declare_toplevel_type(SurrogateLockerThread*)                           \
   declare_toplevel_type(CompactibleFreeListSpace*)                        \
   declare_toplevel_type(CMSCollector*)                                    \
-  declare_toplevel_type(FreeChunk*)                                       \
-  declare_toplevel_type(BinaryTreeDictionary<FreeChunk>*)                 \
-  declare_toplevel_type(FreeBlockDictionary<FreeChunk>*)                  \
-  declare_toplevel_type(FreeList<FreeChunk>*)                             \
-  declare_toplevel_type(FreeList<FreeChunk>)                              \
+  declare_toplevel_type(AFLBinaryTreeDictionary*)                         \
   declare_toplevel_type(LinearAllocBlock)                                 \
   declare_toplevel_type(FreeBlockDictionary<FreeChunk>)                   \
-            declare_type(BinaryTreeDictionary<FreeChunk>, FreeBlockDictionary<FreeChunk>)
+  declare_type(AFLBinaryTreeDictionary, FreeBlockDictionary<FreeChunk>)   \
+            declare_type(AFLBinaryTreeDictionary, FreeBlockDictionary<FreeChunk>) \
 
 #define VM_INT_CONSTANTS_CMS(declare_constant)                            \
   declare_constant(Generation::ConcurrentMarkSweep)                       \

src/share/vm/gc_implementation/shared/vmGCOperations.hpp

@@ -191,7 +191,7 @@ class VM_GenCollectFull: public VM_GC_Operation {
 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
  private:
   MetaWord*                _result;
-  size_t      _size;                       // size of object to be allocated
+  size_t                   _size;     // size of object to be allocated
   Metaspace::MetadataType  _mdtype;
   ClassLoaderData*         _loader_data;
  public:

src/share/vm/memory/binaryTreeDictionary.hpp

@@ -37,77 +37,78 @@
 // A TreeList is a FreeList which can be used to maintain a
 // binary tree of free lists.
 
-template <class Chunk> class TreeChunk;
-template <class Chunk> class BinaryTreeDictionary;
-template <class Chunk> class AscendTreeCensusClosure;
-template <class Chunk> class DescendTreeCensusClosure;
-template <class Chunk> class DescendTreeSearchClosure;
-
-template <class Chunk>
-class TreeList: public FreeList<Chunk> {
-  friend class TreeChunk<Chunk>;
-  friend class BinaryTreeDictionary<Chunk>;
-  friend class AscendTreeCensusClosure<Chunk>;
-  friend class DescendTreeCensusClosure<Chunk>;
-  friend class DescendTreeSearchClosure<Chunk>;
-
-  TreeList<Chunk>* _parent;
-  TreeList<Chunk>* _left;
-  TreeList<Chunk>* _right;
+template <class Chunk_t, template <class> class FreeList_t> class TreeChunk;
+template <class Chunk_t, template <class> class FreeList_t> class BinaryTreeDictionary;
+template <class Chunk_t, template <class> class FreeList_t> class AscendTreeCensusClosure;
+template <class Chunk_t, template <class> class FreeList_t> class DescendTreeCensusClosure;
+template <class Chunk_t, template <class> class FreeList_t> class DescendTreeSearchClosure;
+
+template <class Chunk_t, template <class> class FreeList_t>
+class TreeList : public FreeList_t<Chunk_t> {
+  friend class TreeChunk<Chunk_t, FreeList_t>;
+  friend class BinaryTreeDictionary<Chunk_t, FreeList_t>;
+  friend class AscendTreeCensusClosure<Chunk_t, FreeList_t>;
+  friend class DescendTreeCensusClosure<Chunk_t, FreeList_t>;
+  friend class DescendTreeSearchClosure<Chunk_t, FreeList_t>;
+
+  TreeList<Chunk_t, FreeList_t>* _parent;
+  TreeList<Chunk_t, FreeList_t>* _left;
+  TreeList<Chunk_t, FreeList_t>* _right;
 
  protected:
-  TreeList<Chunk>* parent() const { return _parent; }
-  TreeList<Chunk>* left()   const { return _left;   }
-  TreeList<Chunk>* right()  const { return _right;  }
 
-  // Explicitly import these names into our namespace to fix name lookup with templates
-  using FreeList<Chunk>::head;
-  using FreeList<Chunk>::set_head;
+  TreeList<Chunk_t, FreeList_t>* parent() const { return _parent; }
+  TreeList<Chunk_t, FreeList_t>* left()   const { return _left;   }
+  TreeList<Chunk_t, FreeList_t>* right()  const { return _right;  }
 
-  using FreeList<Chunk>::tail;
-  using FreeList<Chunk>::set_tail;
-  using FreeList<Chunk>::link_tail;
+  // Wrapper on call to base class, to get the template to compile.
+  Chunk_t* head() const { return FreeList_t<Chunk_t>::head(); }
+  Chunk_t* tail() const { return FreeList_t<Chunk_t>::tail(); }
+  void set_head(Chunk_t* head) { FreeList_t<Chunk_t>::set_head(head); }
+  void set_tail(Chunk_t* tail) { FreeList_t<Chunk_t>::set_tail(tail); }
 
-  using FreeList<Chunk>::increment_count;
-  NOT_PRODUCT(using FreeList<Chunk>::increment_returned_bytes_by;)
-  using FreeList<Chunk>::verify_chunk_in_free_list;
-  using FreeList<Chunk>::size;
+  size_t size() const { return FreeList_t<Chunk_t>::size(); }
 
   // Accessors for links in tree.
 
-  void set_left(TreeList<Chunk>* tl) {
+  void set_left(TreeList<Chunk_t, FreeList_t>* tl) {
     _left   = tl;
     if (tl != NULL)
       tl->set_parent(this);
   }
-  void set_right(TreeList<Chunk>* tl) {
+  void set_right(TreeList<Chunk_t, FreeList_t>* tl) {
     _right  = tl;
     if (tl != NULL)
       tl->set_parent(this);
   }
-  void set_parent(TreeList<Chunk>* tl)  { _parent = tl;   }
+  void set_parent(TreeList<Chunk_t, FreeList_t>* tl)  { _parent = tl;   }
 
-  void clearLeft()               { _left = NULL;   }
+  void clear_left()               { _left = NULL;   }
   void clear_right()              { _right = NULL;  }
   void clear_parent()             { _parent = NULL; }
-  void initialize()              { clearLeft(); clear_right(), clear_parent(); }
+  void initialize()               { clear_left(); clear_right(), clear_parent(); FreeList_t<Chunk_t>::initialize(); }
 
   // For constructing a TreeList from a Tree chunk or
   // address and size.
-  static TreeList<Chunk>* as_TreeList(TreeChunk<Chunk>* tc);
-  static TreeList<Chunk>* as_TreeList(HeapWord* addr, size_t size);
+  TreeList();
+  static TreeList<Chunk_t, FreeList_t>*
+          as_TreeList(TreeChunk<Chunk_t, FreeList_t>* tc);
+  static TreeList<Chunk_t, FreeList_t>* as_TreeList(HeapWord* addr, size_t size);
 
   // Returns the head of the free list as a pointer to a TreeChunk.
-  TreeChunk<Chunk>* head_as_TreeChunk();
+  TreeChunk<Chunk_t, FreeList_t>* head_as_TreeChunk();
 
   // Returns the first available chunk in the free list as a pointer
   // to a TreeChunk.
-  TreeChunk<Chunk>* first_available();
+  TreeChunk<Chunk_t, FreeList_t>* first_available();
 
   // Returns the block with the largest heap address amongst
   // those in the list for this size; potentially slow and expensive,
   // use with caution!
-  TreeChunk<Chunk>* largest_address();
+  TreeChunk<Chunk_t, FreeList_t>* largest_address();
+
+  TreeList<Chunk_t, FreeList_t>* get_better_list(
+    BinaryTreeDictionary<Chunk_t, FreeList_t>* dictionary);
 
   // remove_chunk_replace_if_needed() removes the given "tc" from the TreeList.
   // If "tc" is the first chunk in the list, it is also the
@@ -115,10 +116,10 @@ class TreeList: public FreeList<Chunk> {
   // returns the possibly replaced TreeList* for the node in
   // the tree.  It also updates the parent of the original
   // node to point to the new node.
-  TreeList<Chunk>* remove_chunk_replace_if_needed(TreeChunk<Chunk>* tc);
+  TreeList<Chunk_t, FreeList_t>* remove_chunk_replace_if_needed(TreeChunk<Chunk_t, FreeList_t>* tc);
   // See FreeList.
-  void return_chunk_at_head(TreeChunk<Chunk>* tc);
-  void return_chunk_at_tail(TreeChunk<Chunk>* tc);
+  void return_chunk_at_head(TreeChunk<Chunk_t, FreeList_t>* tc);
+  void return_chunk_at_tail(TreeChunk<Chunk_t, FreeList_t>* tc);
 };
 
 // A TreeChunk is a subclass of a Chunk that additionally
@@ -134,52 +135,54 @@ class TreeList: public FreeList<Chunk> {
 // on the free list for a node in the tree and is only removed if
 // it is the last chunk on the free list.
 
-template <class Chunk>
-class TreeChunk : public Chunk {
-  friend class TreeList<Chunk>;
-  TreeList<Chunk>* _list;
-  TreeList<Chunk> _embedded_list;  // if non-null, this chunk is on _list
+template <class Chunk_t, template <class> class FreeList_t>
+class TreeChunk : public Chunk_t {
+  friend class TreeList<Chunk_t, FreeList_t>;
+  TreeList<Chunk_t, FreeList_t>* _list;
+  TreeList<Chunk_t, FreeList_t> _embedded_list;  // if non-null, this chunk is on _list
+
+  static size_t _min_tree_chunk_size;
+
  protected:
-  TreeList<Chunk>* embedded_list() const { return (TreeList<Chunk>*) &_embedded_list; }
-  void set_embedded_list(TreeList<Chunk>* v) { _embedded_list = *v; }
+  TreeList<Chunk_t, FreeList_t>* embedded_list() const { return (TreeList<Chunk_t, FreeList_t>*) &_embedded_list; }
+  void set_embedded_list(TreeList<Chunk_t, FreeList_t>* v) { _embedded_list = *v; }
  public:
-  TreeList<Chunk>* list() { return _list; }
-  void set_list(TreeList<Chunk>* v) { _list = v; }
-  static TreeChunk<Chunk>* as_TreeChunk(Chunk* fc);
+  TreeList<Chunk_t, FreeList_t>* list() { return _list; }
+  void set_list(TreeList<Chunk_t, FreeList_t>* v) { _list = v; }
+  static TreeChunk<Chunk_t, FreeList_t>* as_TreeChunk(Chunk_t* fc);
   // Initialize fields in a TreeChunk that should be
   // initialized when the TreeChunk is being added to
   // a free list in the tree.
   void initialize() { embedded_list()->initialize(); }
 
-  Chunk* next() const { return Chunk::next(); }
-  Chunk* prev() const { return Chunk::prev(); }
-  size_t size() const volatile { return Chunk::size(); }
+  Chunk_t* next() const { return Chunk_t::next(); }
+  Chunk_t* prev() const { return Chunk_t::prev(); }
+  size_t size() const volatile { return Chunk_t::size(); }
+
+  static size_t min_size() {
+    return _min_tree_chunk_size;
+  }
 
   // debugging
   void verify_tree_chunk_list() const;
+  void assert_is_mangled() const;
 };
 
 
-template <class Chunk>
-class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
+template <class Chunk_t, template <class> class FreeList_t>
+class BinaryTreeDictionary: public FreeBlockDictionary<Chunk_t> {
   friend class VMStructs;
-  bool       _splay;
-  bool       _adaptive_freelists;
   size_t     _total_size;
   size_t     _total_free_blocks;
-  TreeList<Chunk>* _root;
+  TreeList<Chunk_t, FreeList_t>* _root;
 
   // private accessors
-  bool splay() const { return _splay; }
-  void set_splay(bool v) { _splay = v; }
   void set_total_size(size_t v) { _total_size = v; }
   virtual void inc_total_size(size_t v);
   virtual void dec_total_size(size_t v);
-  size_t total_free_blocks() const { return _total_free_blocks; }
   void set_total_free_blocks(size_t v) { _total_free_blocks = v; }
-  TreeList<Chunk>* root() const { return _root; }
-  void set_root(TreeList<Chunk>* v) { _root = v; }
-  bool adaptive_freelists() { return _adaptive_freelists; }
+  TreeList<Chunk_t, FreeList_t>* root() const { return _root; }
+  void set_root(TreeList<Chunk_t, FreeList_t>* v) { _root = v; }
 
   // This field is added and can be set to point to the
   // the Mutex used to synchronize access to the
@@ -191,54 +194,55 @@ class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
   // return it.  If the chunk
   // is the last chunk of that size, remove the node for that size
   // from the tree.
-  TreeChunk<Chunk>* get_chunk_from_tree(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither, bool splay);
-  // Return a list of the specified size or NULL from the tree.
-  // The list is not removed from the tree.
-  TreeList<Chunk>* find_list (size_t size) const;
+  TreeChunk<Chunk_t, FreeList_t>* get_chunk_from_tree(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither);
   // Remove this chunk from the tree.  If the removal results
   // in an empty list in the tree, remove the empty list.
-  TreeChunk<Chunk>* remove_chunk_from_tree(TreeChunk<Chunk>* tc);
+  TreeChunk<Chunk_t, FreeList_t>* remove_chunk_from_tree(TreeChunk<Chunk_t, FreeList_t>* tc);
   // Remove the node in the trees starting at tl that has the
   // minimum value and return it.  Repair the tree as needed.
-  TreeList<Chunk>* remove_tree_minimum(TreeList<Chunk>* tl);
-  void       semi_splay_step(TreeList<Chunk>* tl);
+  TreeList<Chunk_t, FreeList_t>* remove_tree_minimum(TreeList<Chunk_t, FreeList_t>* tl);
   // Add this free chunk to the tree.
-  void       insert_chunk_in_tree(Chunk* freeChunk);
+  void       insert_chunk_in_tree(Chunk_t* freeChunk);
  public:
 
-  static const size_t min_tree_chunk_size  = sizeof(TreeChunk<Chunk>)/HeapWordSize;
+  // Return a list of the specified size or NULL from the tree.
+  // The list is not removed from the tree.
+  TreeList<Chunk_t, FreeList_t>* find_list (size_t size) const;
 
   void       verify_tree() const;
   // verify that the given chunk is in the tree.
-  bool       verify_chunk_in_free_list(Chunk* tc) const;
+  bool       verify_chunk_in_free_list(Chunk_t* tc) const;
  private:
-  void          verify_tree_helper(TreeList<Chunk>* tl) const;
-  static size_t verify_prev_free_ptrs(TreeList<Chunk>* tl);
+  void          verify_tree_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
+  static size_t verify_prev_free_ptrs(TreeList<Chunk_t, FreeList_t>* tl);
 
   // Returns the total number of chunks in the list.
-  size_t     total_list_length(TreeList<Chunk>* tl) const;
+  size_t     total_list_length(TreeList<Chunk_t, FreeList_t>* tl) const;
   // Returns the total number of words in the chunks in the tree
   // starting at "tl".
-  size_t     total_size_in_tree(TreeList<Chunk>* tl) const;
+  size_t     total_size_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
   // Returns the sum of the square of the size of each block
   // in the tree starting at "tl".
-  double     sum_of_squared_block_sizes(TreeList<Chunk>* const tl) const;
+  double     sum_of_squared_block_sizes(TreeList<Chunk_t, FreeList_t>* const tl) const;
   // Returns the total number of free blocks in the tree starting
   // at "tl".
-  size_t     total_free_blocks_in_tree(TreeList<Chunk>* tl) const;
-  size_t     num_free_blocks() const;
-  size_t     treeHeight() const;
-  size_t     tree_height_helper(TreeList<Chunk>* tl) const;
-  size_t     total_nodes_in_tree(TreeList<Chunk>* tl) const;
-  size_t     total_nodes_helper(TreeList<Chunk>* tl) const;
+  size_t     total_free_blocks_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
+  size_t     num_free_blocks()  const;
+  size_t     tree_height() const;
+  size_t     tree_height_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
+  size_t     total_nodes_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const;
+  size_t     total_nodes_helper(TreeList<Chunk_t, FreeList_t>* tl) const;
 
  public:
   // Constructor
-  BinaryTreeDictionary(bool adaptive_freelists, bool splay = false);
-  BinaryTreeDictionary(MemRegion mr, bool adaptive_freelists, bool splay = false);
+  BinaryTreeDictionary() :
+    _total_size(0), _total_free_blocks(0), _root(0) {}
+
+  BinaryTreeDictionary(MemRegion mr);
 
   // Public accessors
   size_t total_size() const { return _total_size; }
+  size_t total_free_blocks() const { return _total_free_blocks; }
 
   // Reset the dictionary to the initial conditions with
   // a single free chunk.
@@ -249,23 +253,24 @@ class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
 
   // Return a chunk of size "size" or greater from
   // the tree.
-  // want a better dynamic splay strategy for the future.
-  Chunk* get_chunk(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither) {
-    FreeBlockDictionary<Chunk>::verify_par_locked();
-    Chunk* res = get_chunk_from_tree(size, dither, splay());
+  Chunk_t* get_chunk(size_t size, enum FreeBlockDictionary<Chunk_t>::Dither dither) {
+    FreeBlockDictionary<Chunk_t>::verify_par_locked();
+    Chunk_t* res = get_chunk_from_tree(size, dither);
     assert(res == NULL || res->is_free(),
            "Should be returning a free chunk");
+    assert(dither != FreeBlockDictionary<Chunk_t>::exactly ||
+           res->size() == size, "Not correct size");
     return res;
   }
 
-  void return_chunk(Chunk* chunk) {
-    FreeBlockDictionary<Chunk>::verify_par_locked();
+  void return_chunk(Chunk_t* chunk) {
+    FreeBlockDictionary<Chunk_t>::verify_par_locked();
     insert_chunk_in_tree(chunk);
   }
 
-  void remove_chunk(Chunk* chunk) {
-    FreeBlockDictionary<Chunk>::verify_par_locked();
-    remove_chunk_from_tree((TreeChunk<Chunk>*)chunk);
+  void remove_chunk(Chunk_t* chunk) {
+    FreeBlockDictionary<Chunk_t>::verify_par_locked();
+    remove_chunk_from_tree((TreeChunk<Chunk_t, FreeList_t>*)chunk);
     assert(chunk->is_free(), "Should still be a free chunk");
   }
 
@@ -281,19 +286,19 @@ class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
   }
 
   size_t     min_size() const {
-    return min_tree_chunk_size;
+    return TreeChunk<Chunk_t, FreeList_t>::min_size();
   }
 
   double     sum_of_squared_block_sizes() const {
     return sum_of_squared_block_sizes(root());
   }
 
-  Chunk* find_chunk_ends_at(HeapWord* target) const;
+  Chunk_t* find_chunk_ends_at(HeapWord* target) const;
 
   // Find the list with size "size" in the binary tree and update
   // the statistics in the list according to "split" (chunk was
   // split or coalesce) and "birth" (chunk was added or removed).
-  void       dict_census_udpate(size_t size, bool split, bool birth);
+  void       dict_census_update(size_t size, bool split, bool birth);
   // Return true if the dictionary is overpopulated (more chunks of
   // this size than desired) for size "size".
   bool       coal_dict_over_populated(size_t size);
@@ -307,7 +312,7 @@ class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> {
   // statistics for the sweep.
   void       end_sweep_dict_census(double splitSurplusPercent);
   // Return the largest free chunk in the tree.
-  Chunk* find_largest_dict() const;
+  Chunk_t* find_largest_dict() const;
   // Accessors for statistics
   void       set_tree_surplus(double splitSurplusPercent);
   void       set_tree_hints(void);

src/share/vm/memory/freeBlockDictionary.cpp

@@ -27,6 +27,8 @@
 #include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
 #endif // SERIALGC
 #include "memory/freeBlockDictionary.hpp"
+#include "memory/metablock.hpp"
+#include "memory/metachunk.hpp"
 #ifdef TARGET_OS_FAMILY_linux
 # include "thread_linux.inline.hpp"
 #endif
@@ -62,6 +64,9 @@ template <class Chunk> void FreeBlockDictionary<Chunk>::verify_par_locked() cons
 }
 #endif
 
+template class FreeBlockDictionary<Metablock>;
+template class FreeBlockDictionary<Metachunk>;
+
 #ifndef SERIALGC
 // Explicitly instantiate for FreeChunk
 template class FreeBlockDictionary<FreeChunk>;

src/share/vm/memory/freeBlockDictionary.hpp

@@ -66,7 +66,7 @@ class FreeBlockDictionary: public CHeapObj<mtGC> {
   virtual void       reset(HeapWord* addr, size_t size) = 0;
   virtual void       reset() = 0;
 
-  virtual void       dict_census_udpate(size_t size, bool split, bool birth) = 0;
+  virtual void       dict_census_update(size_t size, bool split, bool birth) = 0;
   virtual bool       coal_dict_over_populated(size_t size) = 0;
   virtual void       begin_sweep_dict_census(double coalSurplusPercent,
                        float inter_sweep_current, float inter_sweep_estimate,

src/share/vm/memory/freeList.cpp

@@ -25,6 +25,8 @@
 #include "precompiled.hpp"
 #include "memory/freeBlockDictionary.hpp"
 #include "memory/freeList.hpp"
+#include "memory/metablock.hpp"
+#include "memory/metachunk.hpp"
 #include "memory/sharedHeap.hpp"
 #include "runtime/globals.hpp"
 #include "runtime/mutex.hpp"
@@ -49,8 +51,6 @@ FreeList<Chunk>::FreeList() :
 {
   _size         = 0;
   _count        = 0;
-  _hint         = 0;
-  init_statistics();
 }
 
 template <class Chunk>
@@ -62,34 +62,50 @@ FreeList<Chunk>::FreeList(Chunk* fc) :
 {
   _size         = fc->size();
   _count        = 1;
-  _hint         = 0;
-  init_statistics();
-#ifndef PRODUCT
-  _allocation_stats.set_returned_bytes(size() * HeapWordSize);
-#endif
 }
 
 template <class Chunk>
-void FreeList<Chunk>::reset(size_t hint) {
+void FreeList<Chunk>::link_head(Chunk* v) {
+  assert_proper_lock_protection();
+  set_head(v);
+  // If this method is not used (just set the head instead),
+  // this check can be avoided.
+  if (v != NULL) {
+    v->link_prev(NULL);
+  }
+}
+
+
+
+template <class Chunk>
+void FreeList<Chunk>::reset() {
+  // Don't set the _size to 0 because this method is
+  // used with a existing list that has a size but which has
+  // been emptied.
+  // Don't clear the _protecting_lock of an existing list.
   set_count(0);
   set_head(NULL);
   set_tail(NULL);
-  set_hint(hint);
 }
 
 template <class Chunk>
-void FreeList<Chunk>::init_statistics(bool split_birth) {
-  _allocation_stats.initialize(split_birth);
+void FreeList<Chunk>::initialize() {
+#ifdef ASSERT
+  // Needed early because it might be checked in other initializing code.
+  set_protecting_lock(NULL);
+#endif
+  reset();
+  set_size(0);
 }
 
-template <class Chunk>
-Chunk* FreeList<Chunk>::get_chunk_at_head() {
+template <class Chunk_t>
+Chunk_t* FreeList<Chunk_t>::get_chunk_at_head() {
   assert_proper_lock_protection();
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
-  Chunk* fc = head();
+  Chunk_t* fc = head();
   if (fc != NULL) {
-    Chunk* nextFC = fc->next();
+    Chunk_t* nextFC = fc->next();
     if (nextFC != NULL) {
       // The chunk fc being removed has a "next".  Set the "next" to the
       // "prev" of fc.
@@ -197,11 +213,6 @@ void FreeList<Chunk>::return_chunk_at_head(Chunk* chunk, bool record_return) {
     link_tail(chunk);
   }
   increment_count(); // of # of chunks in list
-  DEBUG_ONLY(
-    if (record_return) {
-      increment_returned_bytes_by(size()*HeapWordSize);
-    }
-  )
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   assert(head() == NULL || head()->size() == size(), "wrong item on list");
@@ -233,11 +244,6 @@ void FreeList<Chunk>::return_chunk_at_tail(Chunk* chunk, bool record_return) {
   }
   link_tail(chunk);
   increment_count();  // of # of chunks in list
-  DEBUG_ONLY(
-    if (record_return) {
-      increment_returned_bytes_by(size()*HeapWordSize);
-    }
-  )
   assert(head() == NULL || head()->prev() == NULL, "list invariant");
   assert(tail() == NULL || tail()->next() == NULL, "list invariant");
   assert(head() == NULL || head()->size() == size(), "wrong item on list");
@@ -273,7 +279,7 @@ void FreeList<Chunk>::prepend(FreeList<Chunk>* fl) {
   }
 }
 
-// verify_chunk_in_free_list() is used to verify that an item is in this free list.
+// verify_chunk_in_free_lists() is used to verify that an item is in this free list.
 // It is used as a debugging aid.
 template <class Chunk>
 bool FreeList<Chunk>::verify_chunk_in_free_list(Chunk* fc) const {
@@ -293,41 +299,15 @@ bool FreeList<Chunk>::verify_chunk_in_free_list(Chunk* fc) const {
 }
 
 #ifndef PRODUCT
-template <class Chunk>
-void FreeList<Chunk>::verify_stats() const {
-  // The +1 of the LH comparand is to allow some "looseness" in
-  // checking: we usually call this interface when adding a block
-  // and we'll subsequently update the stats; we cannot update the
-  // stats beforehand because in the case of the large-block BT
-  // dictionary for example, this might be the first block and
-  // in that case there would be no place that we could record
-  // the stats (which are kept in the block itself).
-  assert((_allocation_stats.prev_sweep() + _allocation_stats.split_births()
-          + _allocation_stats.coal_births() + 1)   // Total Production Stock + 1
-         >= (_allocation_stats.split_deaths() + _allocation_stats.coal_deaths()
-             + (ssize_t)count()),                // Total Current Stock + depletion
-         err_msg("FreeList " PTR_FORMAT " of size " SIZE_FORMAT
-                 " violates Conservation Principle: "
-                 "prev_sweep(" SIZE_FORMAT ")"
-                 " + split_births(" SIZE_FORMAT ")"
-                 " + coal_births(" SIZE_FORMAT ") + 1 >= "
-                 " split_deaths(" SIZE_FORMAT ")"
-                 " coal_deaths(" SIZE_FORMAT ")"
-                 " + count(" SSIZE_FORMAT ")",
-                 this, _size, _allocation_stats.prev_sweep(), _allocation_stats.split_births(),
-                 _allocation_stats.split_births(), _allocation_stats.split_deaths(),
-                 _allocation_stats.coal_deaths(), count()));
-}
-
 template <class Chunk>
 void FreeList<Chunk>::assert_proper_lock_protection_work() const {
-  assert(_protecting_lock != NULL, "Don't call this directly");
+  assert(protecting_lock() != NULL, "Don't call this directly");
   assert(ParallelGCThreads > 0, "Don't call this directly");
   Thread* thr = Thread::current();
   if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) {
     // assert that we are holding the freelist lock
   } else if (thr->is_GC_task_thread()) {
-    assert(_protecting_lock->owned_by_self(), "FreeList RACE DETECTED");
+    assert(protecting_lock()->owned_by_self(), "FreeList RACE DETECTED");
   } else if (thr->is_Java_thread()) {
     assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing");
   } else {
@@ -350,21 +330,17 @@ void FreeList<Chunk>::print_labels_on(outputStream* st, const char* c) {
 // to the call is a non-null string, it is printed in the first column;
 // otherwise, if the argument is null (the default), then the size of the
 // (free list) block is printed in the first column.
-template <class Chunk>
-void FreeList<Chunk>::print_on(outputStream* st, const char* c) const {
+template <class Chunk_t>
+void FreeList<Chunk_t>::print_on(outputStream* st, const char* c) const {
   if (c != NULL) {
     st->print("%16s", c);
   } else {
     st->print(SIZE_FORMAT_W(16), size());
   }
-  st->print("\t"
-           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t"
-           SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\t" SSIZE_FORMAT_W(14) "\n",
-           bfr_surp(),             surplus(),             desired(),             prev_sweep(),           before_sweep(),
-           count(),               coal_births(),          coal_deaths(),          split_births(),         split_deaths());
 }
 
+template class FreeList<Metablock>;
+template class FreeList<Metachunk>;
 #ifndef SERIALGC
-// Needs to be after the definitions have been seen.
 template class FreeList<FreeChunk>;
 #endif // SERIALGC

src/share/vm/memory/freeList.hpp

@@ -40,23 +40,19 @@ class CompactibleFreeListSpace;
 // for that implementation.
 
 class Mutex;
-template <class Chunk> class TreeList;
-template <class Chunk> class PrintTreeCensusClosure;
 
-template <class Chunk>
+template <class Chunk_t>
 class FreeList VALUE_OBJ_CLASS_SPEC {
   friend class CompactibleFreeListSpace;
   friend class VMStructs;
-  friend class PrintTreeCensusClosure<Chunk>;
 
  private:
-  Chunk*        _head;          // Head of list of free chunks
-  Chunk*        _tail;          // Tail of list of free chunks
+  Chunk_t*      _head;          // Head of list of free chunks
+  Chunk_t*      _tail;          // Tail of list of free chunks
   size_t        _size;          // Size in Heap words of each chunk
   ssize_t       _count;         // Number of entries in list
-  size_t        _hint;          // next larger size list with a positive surplus
 
-  AllocationStats _allocation_stats; // allocation-related statistics
+ protected:
 
 #ifdef ASSERT
   Mutex*        _protecting_lock;
@@ -71,10 +67,6 @@ class FreeList VALUE_OBJ_CLASS_SPEC {
 #endif
   }
 
-  // Initialize the allocation statistics.
- protected:
-  void init_statistics(bool split_birth = false);
-  void set_count(ssize_t v) { _count = v;}
   void increment_count()    {
     _count++;
   }
@@ -89,52 +81,48 @@ class FreeList VALUE_OBJ_CLASS_SPEC {
   // Construct a list without any entries.
   FreeList();
   // Construct a list with "fc" as the first (and lone) entry in the list.
-  FreeList(Chunk* fc);
+  FreeList(Chunk_t* fc);
 
-  // Reset the head, tail, hint, and count of a free list.
-  void reset(size_t hint);
+  // Do initialization
+  void initialize();
+
+  // Reset the head, tail, and count of a free list.
+  void reset();
 
   // Declare the current free list to be protected by the given lock.
 #ifdef ASSERT
-  void set_protecting_lock(Mutex* protecting_lock) {
-    _protecting_lock = protecting_lock;
+  Mutex* protecting_lock() const { return _protecting_lock; }
+  void set_protecting_lock(Mutex* v) {
+    _protecting_lock = v;
   }
 #endif
 
   // Accessors.
-  Chunk* head() const {
+  Chunk_t* head() const {
     assert_proper_lock_protection();
     return _head;
   }
-  void set_head(Chunk* v) {
+  void set_head(Chunk_t* v) {
     assert_proper_lock_protection();
     _head = v;
     assert(!_head || _head->size() == _size, "bad chunk size");
   }
   // Set the head of the list and set the prev field of non-null
   // values to NULL.
-  void link_head(Chunk* v) {
-    assert_proper_lock_protection();
-    set_head(v);
-    // If this method is not used (just set the head instead),
-    // this check can be avoided.
-    if (v != NULL) {
-      v->link_prev(NULL);
-    }
-  }
+  void link_head(Chunk_t* v);
 
-  Chunk* tail() const {
+  Chunk_t* tail() const {
     assert_proper_lock_protection();
     return _tail;
   }
-  void set_tail(Chunk* v) {
+  void set_tail(Chunk_t* v) {
     assert_proper_lock_protection();
     _tail = v;
     assert(!_tail || _tail->size() == _size, "bad chunk size");
   }
   // Set the tail of the list and set the next field of non-null
   // values to NULL.
-  void link_tail(Chunk* v) {
+  void link_tail(Chunk_t* v) {
     assert_proper_lock_protection();
     set_tail(v);
     if (v != NULL) {
@@ -152,174 +140,45 @@ class FreeList VALUE_OBJ_CLASS_SPEC {
     assert_proper_lock_protection();
     _size = v;
   }
-  ssize_t count() const {
-    return _count;
-  }
-  size_t hint() const {
-    return _hint;
-  }
-  void set_hint(size_t v) {
-    assert_proper_lock_protection();
-    assert(v == 0 || _size < v, "Bad hint"); _hint = v;
-  }
-
-  // Accessors for statistics
-  AllocationStats* allocation_stats() {
-    assert_proper_lock_protection();
-    return &_allocation_stats;
-  }
-
-  ssize_t desired() const {
-    return _allocation_stats.desired();
-  }
-  void set_desired(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_desired(v);
-  }
-  void compute_desired(float inter_sweep_current,
-                       float inter_sweep_estimate,
-                       float intra_sweep_estimate) {
-    assert_proper_lock_protection();
-    _allocation_stats.compute_desired(_count,
-                                      inter_sweep_current,
-                                      inter_sweep_estimate,
-                                      intra_sweep_estimate);
-  }
-  ssize_t coal_desired() const {
-    return _allocation_stats.coal_desired();
-  }
-  void set_coal_desired(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_coal_desired(v);
-  }
-
-  ssize_t surplus() const {
-    return _allocation_stats.surplus();
-  }
-  void set_surplus(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_surplus(v);
-  }
-  void increment_surplus() {
-    assert_proper_lock_protection();
-    _allocation_stats.increment_surplus();
-  }
-  void decrement_surplus() {
-    assert_proper_lock_protection();
-    _allocation_stats.decrement_surplus();
-  }
-
-  ssize_t bfr_surp() const {
-    return _allocation_stats.bfr_surp();
-  }
-  void set_bfr_surp(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_bfr_surp(v);
-  }
-  ssize_t prev_sweep() const {
-    return _allocation_stats.prev_sweep();
-  }
-  void set_prev_sweep(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_prev_sweep(v);
-  }
-  ssize_t before_sweep() const {
-    return _allocation_stats.before_sweep();
-  }
-  void set_before_sweep(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_before_sweep(v);
-  }
-
-  ssize_t coal_births() const {
-    return _allocation_stats.coal_births();
-  }
-  void set_coal_births(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_coal_births(v);
-  }
-  void increment_coal_births() {
-    assert_proper_lock_protection();
-    _allocation_stats.increment_coal_births();
-  }
-
-  ssize_t coal_deaths() const {
-    return _allocation_stats.coal_deaths();
-  }
-  void set_coal_deaths(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_coal_deaths(v);
-  }
-  void increment_coal_deaths() {
-    assert_proper_lock_protection();
-    _allocation_stats.increment_coal_deaths();
-  }
-
-  ssize_t split_births() const {
-    return _allocation_stats.split_births();
-  }
-  void set_split_births(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_split_births(v);
-  }
-  void increment_split_births() {
-    assert_proper_lock_protection();
-    _allocation_stats.increment_split_births();
-  }
+  ssize_t count() const { return _count; }
+  void set_count(ssize_t v) { _count = v;}
 
-  ssize_t split_deaths() const {
-    return _allocation_stats.split_deaths();
-  }
-  void set_split_deaths(ssize_t v) {
-    assert_proper_lock_protection();
-    _allocation_stats.set_split_deaths(v);
-  }
-  void increment_split_deaths() {
-    assert_proper_lock_protection();
-    _allocation_stats.increment_split_deaths();
-  }
+  size_t get_better_size() { return size(); }
 
-  NOT_PRODUCT(
-    // For debugging.  The "_returned_bytes" in all the lists are summed
-    // and compared with the total number of bytes swept during a
-    // collection.
-    size_t returned_bytes() const { return _allocation_stats.returned_bytes(); }
-    void set_returned_bytes(size_t v) { _allocation_stats.set_returned_bytes(v); }
-    void increment_returned_bytes_by(size_t v) {
-      _allocation_stats.set_returned_bytes(_allocation_stats.returned_bytes() + v);
-    }
-  )
+  size_t returned_bytes() const { ShouldNotReachHere(); return 0; }
+  void set_returned_bytes(size_t v) {}
+  void increment_returned_bytes_by(size_t v) {}
 
   // Unlink head of list and return it.  Returns NULL if
   // the list is empty.
-  Chunk* get_chunk_at_head();
+  Chunk_t* get_chunk_at_head();
 
   // Remove the first "n" or "count", whichever is smaller, chunks from the
   // list, setting "fl", which is required to be empty, to point to them.
-  void getFirstNChunksFromList(size_t n, FreeList<Chunk>* fl);
+  void getFirstNChunksFromList(size_t n, FreeList<Chunk_t>* fl);
 
   // Unlink this chunk from it's free list
-  void remove_chunk(Chunk* fc);
+  void remove_chunk(Chunk_t* fc);
 
   // Add this chunk to this free list.
-  void return_chunk_at_head(Chunk* fc);
-  void return_chunk_at_tail(Chunk* fc);
+  void return_chunk_at_head(Chunk_t* fc);
+  void return_chunk_at_tail(Chunk_t* fc);
 
   // Similar to returnChunk* but also records some diagnostic
   // information.
-  void return_chunk_at_head(Chunk* fc, bool record_return);
-  void return_chunk_at_tail(Chunk* fc, bool record_return);
+  void return_chunk_at_head(Chunk_t* fc, bool record_return);
+  void return_chunk_at_tail(Chunk_t* fc, bool record_return);
 
   // Prepend "fl" (whose size is required to be the same as that of "this")
   // to the front of "this" list.
-  void prepend(FreeList<Chunk>* fl);
+  void prepend(FreeList<Chunk_t>* fl);
 
   // Verify that the chunk is in the list.
   // found.  Return NULL if "fc" is not found.
-  bool verify_chunk_in_free_list(Chunk* fc) const;
+  bool verify_chunk_in_free_list(Chunk_t* fc) const;
 
   // Stats verification
-  void verify_stats() const PRODUCT_RETURN;
+//  void verify_stats() const { ShouldNotReachHere(); };
 
   // Printing support
   static void print_labels_on(outputStream* st, const char* c);

src/share/vm/memory/metablock.hpp

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+#ifndef SHARE_VM_MEMORY_METABLOCK_HPP
+#define SHARE_VM_MEMORY_METABLOCK_HPP
+
+// Metablock are the unit of allocation from a Chunk.  It is initialized
+// with the size of the requested allocation.  That size is overwritten
+// once the allocation returns.
+//
+// A Metablock may be reused by its SpaceManager but are never moved between
+// SpaceManagers.  There is no explicit link to the Metachunk
+// from which it was allocated.  Metablock may be deallocated and
+// put on a freelist but the space is never freed, rather
+// the Metachunk it is a part of will be deallocated when it's
+// associated class loader is collected.
+
+class Metablock VALUE_OBJ_CLASS_SPEC {
+  friend class VMStructs;
+ private:
+  // Used to align the allocation (see below).
+  union block_t {
+    void* _data[3];
+    struct header_t {
+      size_t _word_size;
+      Metablock* _next;
+      Metablock* _prev;
+    } _header;
+  } _block;
+  static size_t _min_block_byte_size;
+  static size_t _overhead;
+
+  typedef union block_t Block;
+  typedef struct header_t Header;
+  const Block* block() const { return &_block; }
+  const Block::header_t* header() const { return &(block()->_header); }
+ public:
+
+  static Metablock* initialize(MetaWord* p, size_t word_size);
+
+  // This places the body of the block at a 2 word boundary
+  // because every block starts on a 2 word boundary.  Work out
+  // how to make the body on a 2 word boundary if the block
+  // starts on a arbitrary boundary.  JJJ
+
+  size_t word_size() const  { return header()->_word_size; }
+  void set_word_size(size_t v) { _block._header._word_size = v; }
+  size_t size() const volatile { return _block._header._word_size; }
+  void set_size(size_t v) { _block._header._word_size = v; }
+  Metablock* next() const { return header()->_next; }
+  void set_next(Metablock* v) { _block._header._next = v; }
+  Metablock* prev() const { return header()->_prev; }
+  void set_prev(Metablock* v) { _block._header._prev = v; }
+
+  static size_t min_block_byte_size() { return _min_block_byte_size; }
+  static size_t overhead() { return _overhead; }
+
+  bool is_free()                 { return header()->_word_size != 0; }
+  void clear_next()              { set_next(NULL); }
+  void link_prev(Metablock* ptr) { set_prev(ptr); }
+  uintptr_t* end()              { return ((uintptr_t*) this) + size(); }
+  bool cantCoalesce() const     { return false; }
+  void link_next(Metablock* ptr) { set_next(ptr); }
+  void link_after(Metablock* ptr){
+    link_next(ptr);
+    if (ptr != NULL) ptr->link_prev(this);
+  }
+
+  // Should not be needed in a free list of Metablocks
+  void markNotFree()            { ShouldNotReachHere(); }
+
+  // Debug support
+#ifdef ASSERT
+  void* prev_addr() const { return (void*)&_block._header._prev; }
+  void* next_addr() const { return (void*)&_block._header._next; }
+  void* size_addr() const { return (void*)&_block._header._word_size; }
+#endif
+  bool verify_chunk_in_free_list(Metablock* tc) const { return true; }
+  bool verify_par_locked() { return true; }
+
+  void assert_is_mangled() const {/* Don't check "\*/}
+};
+#endif // SHARE_VM_MEMORY_METABLOCK_HPP

src/share/vm/memory/metachunk.hpp

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+#ifndef SHARE_VM_MEMORY_METACHUNK_HPP
+#define SHARE_VM_MEMORY_METACHUNK_HPP
+
+//  Metachunk - Quantum of allocation from a Virtualspace
+//    Metachunks are reused (when freed are put on a global freelist) and
+//    have no permanent association to a SpaceManager.
+
+//            +--------------+ <- end
+//            |              |          --+       ---+
+//            |              |            | free     |
+//            |              |            |          |
+//            |              |            |          | capacity
+//            |              |            |          |
+//            |              | <- top   --+          |
+//            |              |           ---+        |
+//            |              |              | used   |
+//            |              |              |        |
+//            |              |              |        |
+//            +--------------+ <- bottom ---+     ---+
+
+class Metachunk VALUE_OBJ_CLASS_SPEC {
+  // link to support lists of chunks
+  Metachunk* _next;
+  Metachunk* _prev;
+
+  MetaWord* _bottom;
+  MetaWord* _end;
+  MetaWord* _top;
+  size_t _word_size;
+  // Used in a guarantee() so included in the Product builds
+  // even through it is only for debugging.
+  bool _is_free;
+
+  // Metachunks are allocated out of a MetadataVirtualSpace and
+  // and use some of its space to describe itself (plus alignment
+  // considerations).  Metadata is allocated in the rest of the chunk.
+  // This size is the overhead of maintaining the Metachunk within
+  // the space.
+  static size_t _overhead;
+
+  void set_bottom(MetaWord* v) { _bottom = v; }
+  void set_end(MetaWord* v) { _end = v; }
+  void set_top(MetaWord* v) { _top = v; }
+  void set_word_size(size_t v) { _word_size = v; }
+ public:
+#ifdef ASSERT
+  Metachunk() : _bottom(NULL), _end(NULL), _top(NULL), _is_free(false) {}
+#else
+  Metachunk() : _bottom(NULL), _end(NULL), _top(NULL) {}
+#endif
+
+  // Used to add a Metachunk to a list of Metachunks
+  void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");}
+  void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");}
+
+  MetaWord* allocate(size_t word_size);
+  static Metachunk* initialize(MetaWord* ptr, size_t word_size);
+
+  // Accessors
+  Metachunk* next() const { return _next; }
+  Metachunk* prev() const { return _prev; }
+  MetaWord* bottom() const { return _bottom; }
+  MetaWord* end() const { return _end; }
+  MetaWord* top() const { return _top; }
+  size_t word_size() const { return _word_size; }
+  size_t size() const volatile { return _word_size; }
+  void set_size(size_t v) { _word_size = v; }
+  bool is_free() { return _is_free; }
+  void set_is_free(bool v) { _is_free = v; }
+  static size_t overhead() { return _overhead; }
+  void clear_next()              { set_next(NULL); }
+  void link_prev(Metachunk* ptr) { set_prev(ptr); }
+  uintptr_t* end()              { return ((uintptr_t*) this) + size(); }
+  bool cantCoalesce() const     { return false; }
+  void link_next(Metachunk* ptr) { set_next(ptr); }
+  void link_after(Metachunk* ptr){
+    link_next(ptr);
+    if (ptr != NULL) ptr->link_prev(this);
+  }
+
+  // Reset top to bottom so chunk can be reused.
+  void reset_empty() { _top = (_bottom + _overhead); }
+  bool is_empty() { return _top == (_bottom + _overhead); }
+
+  // used (has been allocated)
+  // free (available for future allocations)
+  // capacity (total size of chunk)
+  size_t used_word_size();
+  size_t free_word_size();
+  size_t capacity_word_size();
+
+  // Debug support
+#ifdef ASSERT
+  void* prev_addr() const { return (void*)&_prev; }
+  void* next_addr() const { return (void*)&_next; }
+  void* size_addr() const { return (void*)&_word_size; }
+#endif
+  bool verify_chunk_in_free_list(Metachunk* tc) const { return true; }
+  bool verify_par_locked() { return true; }
+
+  void assert_is_mangled() const {/* Don't check "\*/}
+
+#ifdef ASSERT
+  void mangle();
+#endif // ASSERT
+
+  void print_on(outputStream* st) const;
+  void verify();
+};
+#endif  // SHARE_VM_MEMORY_METACHUNK_HPP

src/share/vm/memory/metaspace.hpp

@@ -57,12 +57,10 @@
 //
 
 class ClassLoaderData;
+class Metablock;
 class MetaWord;
 class Mutex;
 class outputStream;
-class FreeChunk;
-template <class Chunk_t> class FreeList;
-template <class Chunk_t> class BinaryTreeDictionary;
 class SpaceManager;
 
 // Metaspaces each have a  SpaceManager and allocations
@@ -128,7 +126,7 @@ class Metaspace : public CHeapObj<mtClass> {
   size_t capacity_words(MetadataType mdtype) const;
   size_t waste_words(MetadataType mdtype) const;
 
-  static MetaWord* allocate(ClassLoaderData* loader_data, size_t size,
+  static Metablock* allocate(ClassLoaderData* loader_data, size_t size,
                             bool read_only, MetadataType mdtype, TRAPS);
   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);
 

src/share/vm/runtime/vmStructs.cpp

@@ -59,6 +59,7 @@
 #include "memory/generation.hpp"
 #include "memory/generationSpec.hpp"
 #include "memory/heap.hpp"
+#include "memory/metablock.hpp"
 #include "memory/space.hpp"
 #include "memory/tenuredGeneration.hpp"
 #include "memory/universe.hpp"
@@ -249,6 +250,7 @@ typedef TwoOopHashtable<Klass*, mtClass>      KlassTwoOopHashtable;
 typedef Hashtable<Klass*, mtClass>            KlassHashtable;
 typedef HashtableEntry<Klass*, mtClass>       KlassHashtableEntry;
 typedef TwoOopHashtable<Symbol*, mtClass>     SymbolTwoOopHashtable;
+typedef BinaryTreeDictionary<Metablock, FreeList> MetablockTreeDictionary;
 
 //--------------------------------------------------------------------------------
 // VM_STRUCTS
@@ -1237,7 +1239,15 @@ typedef TwoOopHashtable<Symbol*, mtClass>     SymbolTwoOopHashtable;
   nonstatic_field(AccessFlags,                 _flags,                                       jint)                                   \
   nonstatic_field(elapsedTimer,                _counter,                                     jlong)                                  \
   nonstatic_field(elapsedTimer,                _active,                                      bool)                                   \
-  nonstatic_field(InvocationCounter,           _counter,                                     unsigned int)
+  nonstatic_field(InvocationCounter,           _counter,                                     unsigned int)                           \
+  volatile_nonstatic_field(FreeChunk,          _size,                                        size_t)                                 \
+  nonstatic_field(FreeChunk,                   _next,                                        FreeChunk*)                             \
+  nonstatic_field(FreeChunk,                   _prev,                                        FreeChunk*)                             \
+  nonstatic_field(FreeList<FreeChunk>,         _size,                                        size_t)                                 \
+  nonstatic_field(FreeList<Metablock>,         _size,                                        size_t)                                 \
+  nonstatic_field(FreeList<FreeChunk>,         _count,                                       ssize_t)                                \
+  nonstatic_field(FreeList<Metablock>,         _count,                                       ssize_t)                                \
+  nonstatic_field(MetablockTreeDictionary,     _total_size,                                  size_t)
 
   /* NOTE that we do not use the last_entry() macro here; it is used  */
   /* in vmStructs_<os>_<cpu>.hpp's VM_STRUCTS_OS_CPU macro (and must  */
@@ -2080,7 +2090,24 @@ typedef TwoOopHashtable<Symbol*, mtClass>     SymbolTwoOopHashtable;
   declare_toplevel_type(Universe)                                         \
   declare_toplevel_type(vframeArray)                                      \
   declare_toplevel_type(vframeArrayElement)                               \
-  declare_toplevel_type(Annotations*)
+  declare_toplevel_type(Annotations*)                                     \
+                                                                          \
+  /***************/                                                       \
+  /* Miscellaneous types */                                               \
+  /***************/                                                       \
+                                                                          \
+  /* freelist */                                                          \
+  declare_toplevel_type(FreeChunk*)                                       \
+  declare_toplevel_type(Metablock*)                                       \
+  declare_toplevel_type(FreeBlockDictionary<FreeChunk>*)                  \
+  declare_toplevel_type(FreeList<FreeChunk>*)                             \
+  declare_toplevel_type(FreeList<FreeChunk>)                              \
+  declare_toplevel_type(FreeBlockDictionary<Metablock>*)                  \
+  declare_toplevel_type(FreeList<Metablock>*)                             \
+  declare_toplevel_type(FreeList<Metablock>)                              \
+  declare_toplevel_type(MetablockTreeDictionary*)                         \
+  declare_type(MetablockTreeDictionary, FreeBlockDictionary<Metablock>)   \
+              declare_type(MetablockTreeDictionary, FreeBlockDictionary<Metablock>)
 
 
   /* NOTE that we do not use the last_entry() macro here; it is used  */