truffle: src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp comparison

comparison src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp @ 0:a61af66fc99e jdk7-b24

Initial load

author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	6432c3bb6240

comparison

equal deleted inserted replaced

--1:000000000000
+:a61af66fc99e
+/*
+* 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);
+}

Mercurial > hg > truffle

comparison src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp @ 0:a61af66fc99e jdk7-b24