jdk8-mips64-public/hotspot: comparison src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp

--1:000000000000
+:f90c822e73f8
+/*
+* Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*
+*/
+#include "precompiled.hpp"
+#include "gc_implementation/concurrentMarkSweep/cmsLockVerifier.hpp"
+#include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp"
+#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.inline.hpp"
+#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
+#include "gc_implementation/shared/liveRange.hpp"
+#include "gc_implementation/shared/spaceDecorator.hpp"
+#include "gc_interface/collectedHeap.inline.hpp"
+#include "memory/allocation.inline.hpp"
+#include "memory/blockOffsetTable.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "memory/universe.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/globals.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/init.hpp"
+#include "runtime/java.hpp"
+#include "runtime/vmThread.hpp"
+#include "utilities/copy.hpp"
+/////////////////////////////////////////////////////////////////////////
+//// CompactibleFreeListSpace
+/////////////////////////////////////////////////////////////////////////
+// highest ranked  free list lock rank
+int CompactibleFreeListSpace::_lockRank = Mutex::leaf + 3;
+// Defaults are 0 so things will break badly if incorrectly initialized.
+size_t CompactibleFreeListSpace::IndexSetStart  = 0;
+size_t CompactibleFreeListSpace::IndexSetStride = 0;
+size_t MinChunkSize = 0;
+void CompactibleFreeListSpace::set_cms_values() {
+// Set CMS global values
+assert(MinChunkSize == 0, "already set");
+// MinChunkSize should be a multiple of MinObjAlignment and be large enough
+// for chunks to contain a FreeChunk.
+size_t min_chunk_size_in_bytes = align_size_up(sizeof(FreeChunk), MinObjAlignmentInBytes);
+MinChunkSize = min_chunk_size_in_bytes / BytesPerWord;
+assert(IndexSetStart == 0 && IndexSetStride == 0, "already set");
+IndexSetStart  = MinChunkSize;
+IndexSetStride = MinObjAlignment;
+}
+// Constructor
+CompactibleFreeListSpace::CompactibleFreeListSpace(BlockOffsetSharedArray* bs,
+MemRegion mr, bool use_adaptive_freelists,
+FreeBlockDictionary<FreeChunk>::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)
+{
+assert(sizeof(FreeChunk) / BytesPerWord <= MinChunkSize,
+"FreeChunk is larger than expected");
+_bt.set_space(this);
+initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle);
+// We have all of "mr", all of which we place in the dictionary
+// 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<FreeChunk>::dictionaryBinaryTree:
+_dictionary = new AFLBinaryTreeDictionary(mr);
+break;
+case FreeBlockDictionary<FreeChunk>::dictionarySplayTree:
+case FreeBlockDictionary<FreeChunk>::dictionarySkipList:
+default:
+warning("dictionaryChoice: selected option not understood; using"
+" default BinaryTreeDictionary implementation instead.");
+}
+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->get_chunk(mr.word_size(),
+FreeBlockDictionary<FreeChunk>::atLeast);
+// 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;
+}
+check_free_list_consistency();
+// Initialize locks for parallel case.
+if (CollectedHeap::use_parallel_gc_threads()) {
+for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+_indexedFreeListParLocks[i] = new Mutex(Mutex::leaf - 1, // == ExpandHeap_lock - 1
+"a freelist par lock",
+true);
+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");
+}
+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 (size_t 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->set_size(mr.word_size());
+if (mr.word_size() >= IndexSetSize ) {
+returnChunkToDictionary(fc);
+} else {
+_bt.verify_not_unallocated((HeapWord*)fc, fc->size());
+_indexedFreeList[mr.word_size()].return_chunk_at_head(fc);
+}
+coalBirth(mr.word_size());
+}
+_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()->find_largest_dict();
+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_returned_bytes(0);
+}
+}
+size_t CompactibleFreeListSpace::sumIndexedFreeListArrayReturnedBytes() {
+size_t sum = 0;
+for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+sum += _indexedFreeList[i].allocation_stats()->returned_bytes();
+}
+return sum;
+}
+size_t CompactibleFreeListSpace::totalCountInIndexedFreeLists() const {
+size_t count = 0;
+for (size_t i = IndexSetStart; 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()->total_count();
+if (_smallLinearAllocBlock._word_size != 0) {
+num++;
+}
+return num;
+}
+#endif
+bool CompactibleFreeListSpace::is_free_block(const HeapWord* p) const {
+FreeChunk* fc = (FreeChunk*) p;
+return fc->is_free();
+}
+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->total_chunk_size(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->max_chunk_size();
+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 LinearAllocBlock::print_on(outputStream* st) const {
+st->print_cr(" LinearAllocBlock: ptr = " PTR_FORMAT ", word_size = " SIZE_FORMAT
+", refillsize = " SIZE_FORMAT ", allocation_size_limit = " SIZE_FORMAT,
+p2i(_ptr), _word_size, _refillSize, _allocation_size_limit);
+}
+void CompactibleFreeListSpace::print_on(outputStream* st) const {
+st->print_cr("COMPACTIBLE FREELIST SPACE");
+st->print_cr(" Space:");
+Space::print_on(st);
+st->print_cr("promoInfo:");
+_promoInfo.print_on(st);
+st->print_cr("_smallLinearAllocBlock");
+_smallLinearAllocBlock.print_on(st);
+// dump_memory_block(_smallLinearAllocBlock->_ptr, 128);
+st->print_cr(" _fitStrategy = %s, _adaptive_freelists = %s",
+_fitStrategy?"true":"false", _adaptive_freelists?"true":"false");
+}
+void CompactibleFreeListSpace::print_indexed_free_lists(outputStream* st)
+const {
+reportIndexedFreeListStatistics();
+gclog_or_tty->print_cr("Layout of Indexed Freelists");
+gclog_or_tty->print_cr("---------------------------");
+AdaptiveFreeList<FreeChunk>::print_labels_on(st, "size");
+for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+_indexedFreeList[i].print_on(gclog_or_tty);
+for (FreeChunk* fc = _indexedFreeList[i].head(); fc != NULL;
+fc = fc->next()) {
+gclog_or_tty->print_cr("\t[" PTR_FORMAT "," PTR_FORMAT ")  %s",
+p2i(fc), p2i((HeapWord*)fc + i),
+fc->cantCoalesce() ? "\t CC" : "");
+}
+}
+}
+void CompactibleFreeListSpace::print_promo_info_blocks(outputStream* st)
+const {
+_promoInfo.print_on(st);
+}
+void CompactibleFreeListSpace::print_dictionary_free_lists(outputStream* st)
+const {
+_dictionary->report_statistics();
+st->print_cr("Layout of Freelists in Tree");
+st->print_cr("---------------------------");
+_dictionary->print_free_lists(st);
+}
+class BlkPrintingClosure: public BlkClosure {
+const CMSCollector*             _collector;
+const CompactibleFreeListSpace* _sp;
+const CMSBitMap*                _live_bit_map;
+const bool                      _post_remark;
+outputStream*                   _st;
+public:
+BlkPrintingClosure(const CMSCollector* collector,
+const CompactibleFreeListSpace* sp,
+const CMSBitMap* live_bit_map,
+outputStream* st):
+_collector(collector),
+_sp(sp),
+_live_bit_map(live_bit_map),
+_post_remark(collector->abstract_state() > CMSCollector::FinalMarking),
+_st(st) { }
+size_t do_blk(HeapWord* addr);
+};
+size_t BlkPrintingClosure::do_blk(HeapWord* addr) {
+size_t sz = _sp->block_size_no_stall(addr, _collector);
+assert(sz != 0, "Should always be able to compute a size");
+if (_sp->block_is_obj(addr)) {
+const bool dead = _post_remark && !_live_bit_map->isMarked(addr);
+_st->print_cr(PTR_FORMAT ": %s object of size " SIZE_FORMAT "%s",
+p2i(addr),
+dead ? "dead" : "live",
+sz,
+(!dead && CMSPrintObjectsInDump) ? ":" : ".");
+if (CMSPrintObjectsInDump && !dead) {
+oop(addr)->print_on(_st);
+_st->print_cr("--------------------------------------");
+}
+} else { // free block
+_st->print_cr(PTR_FORMAT ": free block of size " SIZE_FORMAT "%s",
+p2i(addr), sz, CMSPrintChunksInDump ? ":" : ".");
+if (CMSPrintChunksInDump) {
+((FreeChunk*)addr)->print_on(_st);
+_st->print_cr("--------------------------------------");
+}
+}
+return sz;
+}
+void CompactibleFreeListSpace::dump_at_safepoint_with_locks(CMSCollector* c,
+outputStream* st) {
+st->print_cr("\n=========================");
+st->print_cr("Block layout in CMS Heap:");
+st->print_cr("=========================");
+BlkPrintingClosure  bpcl(c, this, c->markBitMap(), st);
+blk_iterate(&bpcl);
+st->print_cr("\n=======================================");
+st->print_cr("Order & Layout of Promotion Info Blocks");
+st->print_cr("=======================================");
+print_promo_info_blocks(st);
+st->print_cr("\n===========================");
+st->print_cr("Order of Indexed Free Lists");
+st->print_cr("=========================");
+print_indexed_free_lists(st);
+st->print_cr("\n=================================");
+st->print_cr("Order of Free Lists in Dictionary");
+st->print_cr("=================================");
+print_dictionary_free_lists(st);
+}
+void CompactibleFreeListSpace::reportFreeListStatistics() const {
+assert_lock_strong(&_freelistLock);
+assert(PrintFLSStatistics != 0, "Reporting error");
+_dictionary->report_statistics();
+if (PrintFLSStatistics > 1) {
+reportIndexedFreeListStatistics();
+size_t total_size = totalSizeInIndexedFreeLists() +
+_dictionary->total_chunk_size(DEBUG_ONLY(freelistLock()));
+gclog_or_tty->print(" free=" SIZE_FORMAT " frag=%1.4f\n", total_size, flsFrag());
+}
+}
+void CompactibleFreeListSpace::reportIndexedFreeListStatistics() const {
+assert_lock_strong(&_freelistLock);
+gclog_or_tty->print("Statistics for IndexedFreeLists:\n"
+"--------------------------------\n");
+size_t total_size = totalSizeInIndexedFreeLists();
+size_t   free_blocks = numFreeBlocksInIndexedFreeLists();
+gclog_or_tty->print("Total Free Space: " SIZE_FORMAT "\n", total_size);
+gclog_or_tty->print("Max   Chunk Size: " SIZE_FORMAT "\n", maxChunkSizeInIndexedFreeLists());
+gclog_or_tty->print("Number of Blocks: " SIZE_FORMAT "\n", free_blocks);
+if (free_blocks != 0) {
+gclog_or_tty->print("Av.  Block  Size: " SIZE_FORMAT "\n", total_size/free_blocks);
+}
+}
+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 || !BlockOffsetArrayUseUnallocatedBlock || 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(!BlockOffsetArrayUseUnallocatedBlock || 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(ExtendedOopClosure);
+walk_mem_region_with_cl_DECL(FilteringClosure);
+public:
+FreeListSpace_DCTOC(CompactibleFreeListSpace* sp,
+CMSCollector* collector,
+ExtendedOopClosure* 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) {             \
+bool is_par = SharedHeap::heap()->n_par_threads() > 0;                       \
+if (is_par) {                                                                \
+assert(SharedHeap::heap()->n_par_threads() ==                              \
+SharedHeap::heap()->workers()->active_workers(), "Mismatch");       \
+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(ExtendedOopClosure)
+FreeListSpace_DCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure)
+DirtyCardToOopClosure*
+CompactibleFreeListSpace::new_dcto_cl(ExtendedOopClosure* 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(ExtendedOopClosure* 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, ExtendedOopClosure* 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));
+}
+}
+}
+// Apply the given closure to each live object in the space
+//   The usage of CompactibleFreeListSpace
+// by the ConcurrentMarkSweepGeneration for concurrent GC's allows
+// objects in the space with references to objects that are no longer
+// valid.  For example, an object may reference another object
+// that has already been sweep up (collected).  This method uses
+// obj_is_alive() to determine whether it is safe to apply the closure to
+// an object.  See obj_is_alive() for details on how liveness of an
+// object is decided.
+void CompactibleFreeListSpace::safe_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) && obj_is_alive(cur)) {
+blk->do_object(oop(cur));
+}
+}
+}
+void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr,
+UpwardsObjectClosure* cl) {
+assert_locked(freelistLock());
+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->is_free()) {
+// 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->is_free()) {
+// 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(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());
+// 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.
+while (true) {
+// We must do this until we get a consistent view of the object.
+if (FreeChunk::indicatesFreeChunk(p)) {
+volatile FreeChunk* fc = (volatile FreeChunk*)p;
+size_t res = fc->size();
+// Bugfix for systems with weak memory model (PPC64/IA64). The
+// block's free bit was set and we have read the size of the
+// block. Acquire and check the free bit again. If the block is
+// still free, the read size is correct.
+OrderAccess::acquire();
+// If the object is still a free chunk, return the size, else it
+// has been allocated so try again.
+if (FreeChunk::indicatesFreeChunk(p)) {
+assert(res != 0, "Block size should not be 0");
+return res;
+}
+} else {
+// must read from what 'p' points to in each loop.
+Klass* k = ((volatile oopDesc*)p)->klass_or_null();
+if (k != NULL) {
+assert(k->is_klass(), "Should really be klass oop.");
+oop o = (oop)p;
+assert(o->is_oop(true /* ignore mark word */), "Should be an oop.");
+// Bugfix for systems with weak memory model (PPC64/IA64).
+// The object o may be an array. Acquire to make sure that the array
+// size (third word) is consistent.
+OrderAccess::acquire();
+size_t res = o->size_given_klass(k);
+res = adjustObjectSize(res);
+assert(res != 0, "Block size should not be 0");
+return res;
+}
+}
+}
+}
+// TODO: Now that is_parsable is gone, we should combine these two functions.
+// 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.
+DEBUG_ONLY(uint loops = 0;)
+while (true) {
+// We must do this until we get a consistent view of the object.
+if (FreeChunk::indicatesFreeChunk(p)) {
+volatile FreeChunk* fc = (volatile FreeChunk*)p;
+size_t res = fc->size();
+// Bugfix for systems with weak memory model (PPC64/IA64). The
+// free bit of the block was set and we have read the size of
+// the block. Acquire and check the free bit again. If the
+// block is still free, the read size is correct.
+OrderAccess::acquire();
+if (FreeChunk::indicatesFreeChunk(p)) {
+assert(res != 0, "Block size should not be 0");
+assert(loops == 0, "Should be 0");
+return res;
+}
+} else {
+// must read from what 'p' points to in each loop.
+Klass* k = ((volatile oopDesc*)p)->klass_or_null();
+// We trust the size of any object that has a non-NULL
+// klass and (for those in the perm gen) is parsable
+// -- irrespective of its conc_safe-ty.
+if (k != NULL) {
+assert(k->is_klass(), "Should really be klass oop.");
+oop o = (oop)p;
+assert(o->is_oop(), "Should be an oop");
+// Bugfix for systems with weak memory model (PPC64/IA64).
+// The object o may be an array. Acquire to make sure that the array
+// size (third word) is consistent.
+OrderAccess::acquire();
+size_t res = o->size_given_klass(k);
+res = adjustObjectSize(res);
+assert(res != 0, "Block size should not be 0");
+return res;
+} else {
+// May return 0 if P-bits not present.
+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->is_free()) {
+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(CollectedHeap::use_parallel_gc_threads() || _bt.block_start(p) == p,
+//        "Should be a block boundary");
+if (FreeChunk::indicatesFreeChunk(p)) return false;
+Klass* k = oop(p)->klass_or_null();
+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(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
+"Else races are possible");
+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.
+// NOTE: This method is also used by jmap where, if class unloading is
+// off, the results can return "false" for legitimate perm objects,
+// when we are not in the midst of a sweeping phase, which can result
+// in jmap not reporting certain perm gen objects. This will be moot
+// if/when the perm gen goes away in the future.
+if (_collector->abstract_state() == CMSCollector::Sweeping) {
+CMSBitMap* live_map = _collector->markBitMap();
+return live_map->par_isMarked((HeapWord*) p);
+}
+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->is_free()) {
+// 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->is_free(), "shouldn't be marked free");
+assert(oop(fc)->klass_or_null() == 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) {
+AdaptiveFreeList<FreeChunk>* fl = &_indexedFreeList[i];
+if (fl->head()) {
+ret = getFromListGreater(fl, numWords);
+assert(ret == NULL || ret->is_free(), "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()->get_chunk(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->is_free(), "This chunk should be free");
+ret->link_prev(NULL);
+}
+assert(ret == NULL || ret->is_free(), "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()].verify_chunk_in_free_list(fc);
+}
+bool CompactibleFreeListSpace::verify_chunk_is_linear_alloc_block(FreeChunk* fc) const {
+assert((_smallLinearAllocBlock._ptr != (HeapWord*)fc) ||
+(_smallLinearAllocBlock._word_size == fc->size()),
+"Linear allocation block shows incorrect size");
+return ((_smallLinearAllocBlock._ptr == (HeapWord*)fc) &&
+(_smallLinearAllocBlock._word_size == fc->size()));
+}
+// Check if the purported free chunk is present either as a linear
+// allocation block, the size-indexed table of (smaller) free blocks,
+// or the larger free blocks kept in the binary tree dictionary.
+bool CompactibleFreeListSpace::verify_chunk_in_free_list(FreeChunk* fc) const {
+if (verify_chunk_is_linear_alloc_block(fc)) {
+return true;
+} else if (fc->size() < IndexSetSize) {
+return verifyChunkInIndexedFreeLists(fc);
+} else {
+return dictionary()->verify_chunk_in_free_list(fc);
+}
+}
+#ifndef PRODUCT
+void CompactibleFreeListSpace::assert_locked() const {
+CMSLockVerifier::assert_locked(freelistLock(), parDictionaryAllocLock());
+}
+void CompactibleFreeListSpace::assert_locked(const Mutex* lock) const {
+CMSLockVerifier::assert_locked(lock);
+}
+#endif
+FreeChunk* CompactibleFreeListSpace::allocateScratch(size_t size) {
+// In the parallel case, the main thread holds the free list lock
+// on behalf the parallel threads.
+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->is_free(), "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) {
+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) {
+size_t sz = blk->_word_size;
+// 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 (sz < SmallForDictionary) {
+_bt.allocated(blk->_ptr, sz);
+}
+// Return the chunk that isn't big enough, and then refill below.
+addChunkToFreeLists(blk->_ptr, sz);
+split_birth(sz);
+// 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) {
+split_birth(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;
+split_birth(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.
+OrderAccess::storestore();
+_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;
+split_birth(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.
+OrderAccess::storestore();
+_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].get_chunk_at_head();
+if (res == NULL) {
+res = getChunkFromIndexedFreeListHelper(size);
+}
+_bt.verify_not_unallocated((HeapWord*) res, size);
+assert(res == NULL || res->size() == size, "Incorrect block size");
+return res;
+}
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromIndexedFreeListHelper(size_t size,
+bool replenish) {
+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;
+const 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].get_chunk_at_head();
+} else if (bestFitFirst()) {
+newFc = bestFitSmall(replenish_size);
+}
+}
+if (newFc == NULL && replenish_size > size) {
+assert(CMSIndexedFreeListReplenish > 1, "ctl pt invariant");
+newFc = getChunkFromIndexedFreeListHelper(replenish_size, false);
+}
+// Note: The stats update re split-death of block obtained above
+// will be recorded below precisely when we know we are going to
+// be actually splitting it into more than one pieces below.
+if (newFc != NULL) {
+if  (replenish || CMSReplenishIntermediate) {
+// Replenish this list and return one block to caller.
+size_t i;
+FreeChunk *curFc, *nextFc;
+size_t num_blk = newFc->size() / size;
+assert(num_blk >= 1, "Smaller than requested?");
+assert(newFc->size() % size == 0, "Should be integral multiple of request");
+if (num_blk > 1) {
+// we are sure we will be splitting the block just obtained
+// into multiple pieces; record the split-death of the original
+splitDeath(replenish_size);
+}
+// carve up and link blocks 0, ..., num_blk - 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 < (num_blk - 1);
+curFc = nextFc, nextFc = (FreeChunk*)((HeapWord*)nextFc + size),
+i++) {
+curFc->set_size(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].return_chunk_at_tail(curFc, false);
+_bt.mark_block((HeapWord*)curFc, size);
+split_birth(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 + num_blk*size,
+"inconsistency in carving newFc");
+curFc->set_size(size);
+_bt.mark_block((HeapWord*)curFc, size);
+split_birth(size);
+fc = curFc;
+} else {
+// Return entire block to caller
+fc = newFc;
+}
+}
+}
+} 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->is_free(), "Should be returning a free chunk");
+return fc;
+}
+FreeChunk*
+CompactibleFreeListSpace::getChunkFromDictionary(size_t size) {
+assert_locked();
+FreeChunk* fc = _dictionary->get_chunk(size,
+FreeBlockDictionary<FreeChunk>::atLeast);
+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->get_chunk(size,
+FreeBlockDictionary<FreeChunk>::atLeast);
+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, "get_chunk() guarantee");
+if (fc->size() < size + MinChunkSize) {
+// Return the chunk to the dictionary and go get a bigger one.
+returnChunkToDictionary(fc);
+fc = _dictionary->get_chunk(size + MinChunkSize,
+FreeBlockDictionary<FreeChunk>::atLeast);
+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->return_chunk(chunk);
+#ifndef PRODUCT
+if (CMSCollector::abstract_state() != CMSCollector::Sweeping) {
+TreeChunk<FreeChunk, AdaptiveFreeList<FreeChunk> >* tc = TreeChunk<FreeChunk, AdaptiveFreeList<FreeChunk> >::as_TreeChunk(chunk);
+TreeList<FreeChunk, AdaptiveFreeList<FreeChunk> >* tl = tc->list();
+tl->verify_stats();
+}
+#endif // PRODUCT
+}
+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].return_chunk_at_tail(fc);
+} else {
+_indexedFreeList[size].return_chunk_at_head(fc);
+}
+#ifndef PRODUCT
+if (CMSCollector::abstract_state() != CMSCollector::Sweeping) {
+_indexedFreeList[size].verify_stats();
+}
+#endif // PRODUCT
+}
+// 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!");
+// 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()->find_largest_dict();  // get largest block
+if (ec != NULL && ec->end() == (uintptr_t*) chunk) {
+// It's a coterminal block - we can coalesce.
+size_t old_size = ec->size();
+coalDeath(old_size);
+removeChunkFromDictionary(ec);
+size += old_size;
+} else {
+ec = (FreeChunk*)chunk;
+}
+}
+ec->set_size(size);
+debug_only(ec->mangleFreed(size));
+if (size < SmallForDictionary && ParallelGCThreads != 0) {
+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->set_size(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->remove_chunk(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].remove_chunk(fc);
+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) {
+AdaptiveFreeList<FreeChunk>* it   = _indexedFreeList;
+size_t    hint = _indexedFreeList[start].hint();
+while (hint < IndexSetSize) {
+assert(hint % MinObjAlignment == 0, "hint should be aligned");
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[hint];
+if (fl->surplus() > 0 && fl->head() != NULL) {
+// Found a list with surplus, reset original hint
+// and split out a free chunk which is returned.
+_indexedFreeList[start].set_hint(hint);
+FreeChunk* res = getFromListGreater(fl, numWords);
+assert(res == NULL || res->is_free(),
+"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(AdaptiveFreeList<FreeChunk>* 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->remove_chunk(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->is_free(),
+"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->set_size(rem_size);
+ffc->link_next(NULL);
+ffc->link_prev(NULL); // Mark as a free block for other (parallel) GC threads.
+// Above must occur before BOT is updated below.
+// adjust block offset table
+OrderAccess::storestore();
+assert(chunk->is_free() && ffc->is_free(), "Error");
+_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();
+assert(!is_par ||
+(SharedHeap::heap()->n_par_threads() ==
+SharedHeap::heap()->workers()->active_workers()), "Mismatch");
+returnChunkToFreeList(ffc);
+split(size, rem_size);
+if (is_par) _indexedFreeListParLocks[rem_size]->unlock();
+} else {
+returnChunkToDictionary(ffc);
+split(size ,rem_size);
+}
+chunk->set_size(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() {
+assert(Thread::current()->is_VM_thread(),
+"Global variable should only be set when single-threaded");
+// 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(unallocated_block());
+#ifdef ASSERT
+// Check the sanity of save_marks() etc.
+MemRegion ur    = used_region();
+MemRegion urasm = used_region_at_save_marks();
+assert(ur.contains(urasm),
+err_msg(" Error at save_marks(): [" PTR_FORMAT "," PTR_FORMAT ")"
+" should contain [" PTR_FORMAT "," PTR_FORMAT ")",
+p2i(ur.start()), p2i(ur.end()), p2i(urasm.start()), p2i(urasm.end())));
+#endif
+// 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?");
+assert(SharedHeap::heap()->n_par_threads() == 0,
+"Shouldn't be called if using parallel 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)
+bool CompactibleFreeListSpace::linearAllocationWouldFail() const {
+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->set_size(blk->_word_size);
+fc->link_prev(NULL);   // mark as free
+fc->dontCoalesce();
+assert(fc->is_free(), "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 concurrent collection policy decisions.
+bool CompactibleFreeListSpace::should_concurrent_collect() const {
+// In the future we might want to add in frgamentation stats --
+// including erosion of the "mountain" into this decision as well.
+return !adaptive_freelists() && linearAllocationWouldFail();
+}
+// 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->total_chunk_size(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;
+}
+void CompactibleFreeListSpace::beginSweepFLCensus(
+float inter_sweep_current,
+float inter_sweep_estimate,
+float intra_sweep_estimate) {
+assert_locked();
+size_t i;
+for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+AdaptiveFreeList<FreeChunk>* fl    = &_indexedFreeList[i];
+if (PrintFLSStatistics > 1) {
+gclog_or_tty->print("size[" SIZE_FORMAT "] : ", i);
+}
+fl->compute_desired(inter_sweep_current, inter_sweep_estimate, intra_sweep_estimate);
+fl->set_coal_desired((ssize_t)((double)fl->desired() * CMSSmallCoalSurplusPercent));
+fl->set_before_sweep(fl->count());
+fl->set_bfr_surp(fl->surplus());
+}
+_dictionary->begin_sweep_dict_census(CMSLargeCoalSurplusPercent,
+inter_sweep_current,
+inter_sweep_estimate,
+intra_sweep_estimate);
+}
+void CompactibleFreeListSpace::setFLSurplus() {
+assert_locked();
+size_t i;
+for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
+fl->set_surplus(fl->count() -
+(ssize_t)((double)fl->desired() * CMSSmallSplitSurplusPercent));
+}
+}
+void CompactibleFreeListSpace::setFLHints() {
+assert_locked();
+size_t i;
+size_t h = IndexSetSize;
+for (i = IndexSetSize - 1; i != 0; i -= IndexSetStride) {
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
+fl->set_hint(h);
+if (fl->surplus() > 0) {
+h = i;
+}
+}
+}
+void CompactibleFreeListSpace::clearFLCensus() {
+assert_locked();
+size_t i;
+for (i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
+fl->set_prev_sweep(fl->count());
+fl->set_coal_births(0);
+fl->set_coal_deaths(0);
+fl->set_split_births(0);
+fl->set_split_deaths(0);
+}
+}
+void CompactibleFreeListSpace::endSweepFLCensus(size_t sweep_count) {
+if (PrintFLSStatistics > 0) {
+HeapWord* largestAddr = (HeapWord*) dictionary()->find_largest_dict();
+gclog_or_tty->print_cr("CMS: Large block " PTR_FORMAT,
+p2i(largestAddr));
+}
+setFLSurplus();
+setFLHints();
+if (PrintGC && PrintFLSCensus > 0) {
+printFLCensus(sweep_count);
+}
+clearFLCensus();
+assert_locked();
+_dictionary->end_sweep_dict_census(CMSLargeSplitSurplusPercent);
+}
+bool CompactibleFreeListSpace::coalOverPopulated(size_t size) {
+if (size < SmallForDictionary) {
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
+return (fl->coal_desired() < 0) ||
+((int)fl->count() > fl->coal_desired());
+} else {
+return dictionary()->coal_dict_over_populated(size);
+}
+}
+void CompactibleFreeListSpace::smallCoalBirth(size_t size) {
+assert(size < SmallForDictionary, "Size too large for indexed list");
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
+fl->increment_coal_births();
+fl->increment_surplus();
+}
+void CompactibleFreeListSpace::smallCoalDeath(size_t size) {
+assert(size < SmallForDictionary, "Size too large for indexed list");
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
+fl->increment_coal_deaths();
+fl->decrement_surplus();
+}
+void CompactibleFreeListSpace::coalBirth(size_t size) {
+if (size  < SmallForDictionary) {
+smallCoalBirth(size);
+} else {
+dictionary()->dict_census_update(size,
+false /* split */,
+true /* birth */);
+}
+}
+void CompactibleFreeListSpace::coalDeath(size_t size) {
+if(size  < SmallForDictionary) {
+smallCoalDeath(size);
+} else {
+dictionary()->dict_census_update(size,
+false /* split */,
+false /* birth */);
+}
+}
+void CompactibleFreeListSpace::smallSplitBirth(size_t size) {
+assert(size < SmallForDictionary, "Size too large for indexed list");
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
+fl->increment_split_births();
+fl->increment_surplus();
+}
+void CompactibleFreeListSpace::smallSplitDeath(size_t size) {
+assert(size < SmallForDictionary, "Size too large for indexed list");
+AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[size];
+fl->increment_split_deaths();
+fl->decrement_surplus();
+}
+void CompactibleFreeListSpace::split_birth(size_t size) {
+if (size  < SmallForDictionary) {
+smallSplitBirth(size);
+} else {
+dictionary()->dict_census_update(size,
+true /* split */,
+true /* birth */);
+}
+}
+void CompactibleFreeListSpace::splitDeath(size_t size) {
+if (size  < SmallForDictionary) {
+smallSplitDeath(size);
+} else {
+dictionary()->dict_census_update(size,
+true /* split */,
+false /* birth */);
+}
+}
+void CompactibleFreeListSpace::split(size_t from, size_t to1) {
+size_t to2 = from - to1;
+splitDeath(from);
+split_birth(to1);
+split_birth(to2);
+}
+void CompactibleFreeListSpace::print() const {
+print_on(tty);
+}
+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 {
+private:
+const CompactibleFreeListSpace* _sp;
+const MemRegion                 _span;
+HeapWord*                       _last_addr;
+size_t                          _last_size;
+bool                            _last_was_obj;
+bool                            _last_was_live;
+public:
+VerifyAllBlksClosure(const CompactibleFreeListSpace* sp,
+MemRegion span) :  _sp(sp), _span(span),
+_last_addr(NULL), _last_size(0),
+_last_was_obj(false), _last_was_live(false) { }
+virtual size_t do_blk(HeapWord* addr) {
+size_t res;
+bool   was_obj  = false;
+bool   was_live = false;
+if (_sp->block_is_obj(addr)) {
+was_obj = true;
+oop p = oop(addr);
+guarantee(p->is_oop(), "Should be an oop");
+res = _sp->adjustObjectSize(p->size());
+if (_sp->obj_is_alive(addr)) {
+was_live = true;
+p->verify();
+}
+} else {
+FreeChunk* fc = (FreeChunk*)addr;
+res = fc->size();
+if (FLSVerifyLists && !fc->cantCoalesce()) {
+guarantee(_sp->verify_chunk_in_free_list(fc),
+"Chunk should be on a free list");
+}
+}
+if (res == 0) {
+gclog_or_tty->print_cr("Livelock: no rank reduction!");
+gclog_or_tty->print_cr(
+" Current:  addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n"
+" Previous: addr = " PTR_FORMAT ", size = " SIZE_FORMAT ", obj = %s, live = %s \n",
+p2i(addr),       res,        was_obj      ?"true":"false", was_live      ?"true":"false",
+p2i(_last_addr), _last_size, _last_was_obj?"true":"false", _last_was_live?"true":"false");
+_sp->print_on(gclog_or_tty);
+guarantee(false, "Seppuku!");
+}
+_last_addr = addr;
+_last_size = res;
+_last_was_obj  = was_obj;
+_last_was_live = was_live;
+return res;
+}
+};
+class VerifyAllOopsClosure: public OopClosure {
+private:
+const CMSCollector*             _collector;
+const CompactibleFreeListSpace* _sp;
+const MemRegion                 _span;
+const bool                      _past_remark;
+const CMSBitMap*                _bit_map;
+protected:
+void do_oop(void* p, oop obj) {
+if (_span.contains(obj)) { // the interior oop points into CMS heap
+if (!_span.contains(p)) { // 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(obj) ||
+_sp->block_is_obj((HeapWord*)obj),
+"Should be an object");
+guarantee(obj->is_oop(), "Should be an oop");
+obj->verify();
+if (_past_remark) {
+// Remark has been completed, the object should be marked
+_bit_map->isMarked((HeapWord*)obj);
+}
+} 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(p))) {
+guarantee(_bit_map->isMarked((HeapWord*)obj), "Marking error?");
+}
+}
+}
+} else if (_sp->is_in_reserved(p)) {
+// the reference is from FLS, and points out of FLS
+guarantee(obj->is_oop(), "Should be an oop");
+obj->verify();
+}
+}
+template <class T> void do_oop_work(T* p) {
+T heap_oop = oopDesc::load_heap_oop(p);
+if (!oopDesc::is_null(heap_oop)) {
+oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
+do_oop(p, obj);
+}
+}
+public:
+VerifyAllOopsClosure(const CMSCollector* collector,
+const CompactibleFreeListSpace* sp, MemRegion span,
+bool past_remark, CMSBitMap* bit_map) :
+_collector(collector), _sp(sp), _span(span),
+_past_remark(past_remark), _bit_map(bit_map) { }
+virtual void do_oop(oop* p)       { VerifyAllOopsClosure::do_oop_work(p); }
+virtual void do_oop(narrowOop* p) { VerifyAllOopsClosure::do_oop_work(p); }
+};
+void CompactibleFreeListSpace::verify() 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();
+// Iterate over all oops in the heap. Uses the _no_header version
+// since we are not interested in following the klass pointers.
+ch->oop_iterate_no_header(&cl);
+}
+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 < IndexSetStart; i++) {
+guarantee(_indexedFreeList[i].head() == NULL, "should be NULL");
+}
+for (; i < IndexSetSize; i++) {
+verifyIndexedFreeList(i);
+}
+}
+void CompactibleFreeListSpace::verifyIndexedFreeList(size_t size) const {
+FreeChunk* fc   =  _indexedFreeList[size].head();
+FreeChunk* tail =  _indexedFreeList[size].tail();
+size_t    num = _indexedFreeList[size].count();
+size_t      n = 0;
+guarantee(((size >= IndexSetStart) && (size % IndexSetStride == 0)) || fc == NULL,
+"Slot should have been empty");
+for (; fc != NULL; fc = fc->next(), n++) {
+guarantee(fc->size() == size, "Size inconsistency");
+guarantee(fc->is_free(), "!free?");
+guarantee(fc->next() == NULL || fc->next()->prev() == fc, "Broken list");
+guarantee((fc->next() == NULL) == (fc == tail), "Incorrect tail");
+}
+guarantee(n == num, "Incorrect count");
+}
+#ifndef PRODUCT
+void CompactibleFreeListSpace::check_free_list_consistency() const {
+assert((TreeChunk<FreeChunk, AdaptiveFreeList<FreeChunk> >::min_size() <= IndexSetSize),
+"Some sizes can't be allocated without recourse to"
+" linear allocation buffers");
+assert((TreeChunk<FreeChunk, AdaptiveFreeList<FreeChunk> >::min_size()*HeapWordSize == sizeof(TreeChunk<FreeChunk, AdaptiveFreeList<FreeChunk> >)),
+"else MIN_TREE_CHUNK_SIZE is wrong");
+assert(IndexSetStart != 0, "IndexSetStart not initialized");
+assert(IndexSetStride != 0, "IndexSetStride not initialized");
+}
+#endif
+void CompactibleFreeListSpace::printFLCensus(size_t sweep_count) const {
+assert_lock_strong(&_freelistLock);
+AdaptiveFreeList<FreeChunk> total;
+gclog_or_tty->print("end sweep# " SIZE_FORMAT "\n", sweep_count);
+AdaptiveFreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
+size_t total_free = 0;
+for (size_t i = IndexSetStart; i < IndexSetSize; i += IndexSetStride) {
+const AdaptiveFreeList<FreeChunk> *fl = &_indexedFreeList[i];
+total_free += fl->count() * fl->size();
+if (i % (40*IndexSetStride) == 0) {
+AdaptiveFreeList<FreeChunk>::print_labels_on(gclog_or_tty, "size");
+}
+fl->print_on(gclog_or_tty);
+total.set_bfr_surp(    total.bfr_surp()     + fl->bfr_surp()    );
+total.set_surplus(    total.surplus()     + fl->surplus()    );
+total.set_desired(    total.desired()     + fl->desired()    );
+total.set_prev_sweep(  total.prev_sweep()   + fl->prev_sweep()  );
+total.set_before_sweep(total.before_sweep() + fl->before_sweep());
+total.set_count(      total.count()       + fl->count()      );
+total.set_coal_births( total.coal_births()  + fl->coal_births() );
+total.set_coal_deaths( total.coal_deaths()  + fl->coal_deaths() );
+total.set_split_births(total.split_births() + fl->split_births());
+total.set_split_deaths(total.split_deaths() + fl->split_deaths());
+}
+total.print_on(gclog_or_tty, "TOTAL");
+gclog_or_tty->print_cr("Total free in indexed lists "
+SIZE_FORMAT " words", total_free);
+gclog_or_tty->print("growth: %8.5f  deficit: %8.5f\n",
+(double)(total.split_births()+total.coal_births()-total.split_deaths()-total.coal_deaths())/
+(total.prev_sweep() != 0 ? (double)total.prev_sweep() : 1.0),
+(double)(total.desired() - total.count())/(total.desired() != 0 ? (double)total.desired() : 1.0));
+_dictionary->print_dict_census();
+}
+///////////////////////////////////////////////////////////////////////////
+// CFLS_LAB
+///////////////////////////////////////////////////////////////////////////
+#define VECTOR_257(x)                                                                                  \
+/* 1  2  3  4  5  6  7  8  9 1x 11 12 13 14 15 16 17 18 19 2x 21 22 23 24 25 26 27 28 29 3x 31 32 */ \
+{  x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,   \
+x }
+// Initialize with default setting of CMSParPromoteBlocksToClaim, _not_
+// OldPLABSize, whose static default is different; if overridden at the
+// command-line, this will get reinitialized via a call to
+// modify_initialization() below.
+AdaptiveWeightedAverage CFLS_LAB::_blocks_to_claim[]    =
+VECTOR_257(AdaptiveWeightedAverage(OldPLABWeight, (float)CMSParPromoteBlocksToClaim));
+size_t CFLS_LAB::_global_num_blocks[]  = VECTOR_257(0);
+uint   CFLS_LAB::_global_num_workers[] = VECTOR_257(0);
+CFLS_LAB::CFLS_LAB(CompactibleFreeListSpace* cfls) :
+_cfls(cfls)
+{
+assert(CompactibleFreeListSpace::IndexSetSize == 257, "Modify VECTOR_257() macro above");
+for (size_t i = CompactibleFreeListSpace::IndexSetStart;
+i < CompactibleFreeListSpace::IndexSetSize;
+i += CompactibleFreeListSpace::IndexSetStride) {
+_indexedFreeList[i].set_size(i);
+_num_blocks[i] = 0;
+}
+}
+static bool _CFLS_LAB_modified = false;
+void CFLS_LAB::modify_initialization(size_t n, unsigned wt) {
+assert(!_CFLS_LAB_modified, "Call only once");
+_CFLS_LAB_modified = true;
+for (size_t i = CompactibleFreeListSpace::IndexSetStart;
+i < CompactibleFreeListSpace::IndexSetSize;
+i += CompactibleFreeListSpace::IndexSetStride) {
+_blocks_to_claim[i].modify(n, wt, true /* force */);
+}
+}
+HeapWord* CFLS_LAB::alloc(size_t word_sz) {
+FreeChunk* res;
+assert(word_sz == _cfls->adjustObjectSize(word_sz), "Error");
+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 {
+AdaptiveFreeList<FreeChunk>* fl = &_indexedFreeList[word_sz];
+if (fl->count() == 0) {
+// Attempt to refill this local free list.
+get_from_global_pool(word_sz, fl);
+// If it didn't work, give up.
+if (fl->count() == 0) return NULL;
+}
+res = fl->get_chunk_at_head();
+assert(res != NULL, "Why was count non-zero?");
+}
+res->markNotFree();
+assert(!res->is_free(), "shouldn't be marked free");
+assert(oop(res)->klass_or_null() == NULL, "should look uninitialized");
+// mangle a just allocated object with a distinct pattern.
+debug_only(res->mangleAllocated(word_sz));
+return (HeapWord*)res;
+}
+// Get a chunk of blocks of the right size and update related
+// book-keeping stats
+void CFLS_LAB::get_from_global_pool(size_t word_sz, AdaptiveFreeList<FreeChunk>* fl) {
+// Get the #blocks we want to claim
+size_t n_blks = (size_t)_blocks_to_claim[word_sz].average();
+assert(n_blks > 0, "Error");
+assert(ResizePLAB || n_blks == OldPLABSize, "Error");
+// In some cases, when the application has a phase change,
+// there may be a sudden and sharp shift in the object survival
+// profile, and updating the counts at the end of a scavenge
+// may not be quick enough, giving rise to large scavenge pauses
+// during these phase changes. It is beneficial to detect such
+// changes on-the-fly during a scavenge and avoid such a phase-change
+// pothole. The following code is a heuristic attempt to do that.
+// It is protected by a product flag until we have gained
+// enough experience with this heuristic and fine-tuned its behaviour.
+// WARNING: This might increase fragmentation if we overreact to
+// small spikes, so some kind of historical smoothing based on
+// previous experience with the greater reactivity might be useful.
+// Lacking sufficient experience, CMSOldPLABResizeQuicker is disabled by
+// default.
+if (ResizeOldPLAB && CMSOldPLABResizeQuicker) {
+size_t multiple = _num_blocks[word_sz]/(CMSOldPLABToleranceFactor*CMSOldPLABNumRefills*n_blks);
+n_blks +=  CMSOldPLABReactivityFactor*multiple*n_blks;
+n_blks = MIN2(n_blks, CMSOldPLABMax);
+}
+assert(n_blks > 0, "Error");
+_cfls->par_get_chunk_of_blocks(word_sz, n_blks, fl);
+// Update stats table entry for this block size
+_num_blocks[word_sz] += fl->count();
+}
+void CFLS_LAB::compute_desired_plab_size() {
+for (size_t i =  CompactibleFreeListSpace::IndexSetStart;
+i < CompactibleFreeListSpace::IndexSetSize;
+i += CompactibleFreeListSpace::IndexSetStride) {
+assert((_global_num_workers[i] == 0) == (_global_num_blocks[i] == 0),
+"Counter inconsistency");
+if (_global_num_workers[i] > 0) {
+// Need to smooth wrt historical average
+if (ResizeOldPLAB) {
+_blocks_to_claim[i].sample(
+MAX2((size_t)CMSOldPLABMin,
+MIN2((size_t)CMSOldPLABMax,
+_global_num_blocks[i]/(_global_num_workers[i]*CMSOldPLABNumRefills))));
+}
+// Reset counters for next round
+_global_num_workers[i] = 0;
+_global_num_blocks[i] = 0;
+if (PrintOldPLAB) {
+gclog_or_tty->print_cr("[" SIZE_FORMAT "]: " SIZE_FORMAT, i, (size_t)_blocks_to_claim[i].average());
+}
+}
+}
+}
+// If this is changed in the future to allow parallel
+// access, one would need to take the FL locks and,
+// depending on how it is used, stagger access from
+// parallel threads to reduce contention.
+void CFLS_LAB::retire(int tid) {
+// We run this single threaded with the world stopped;
+// so no need for locks and such.
+NOT_PRODUCT(Thread* t = Thread::current();)
+assert(Thread::current()->is_VM_thread(), "Error");
+for (size_t i =  CompactibleFreeListSpace::IndexSetStart;
+i < CompactibleFreeListSpace::IndexSetSize;
+i += CompactibleFreeListSpace::IndexSetStride) {
+assert(_num_blocks[i] >= (size_t)_indexedFreeList[i].count(),
+"Can't retire more than what we obtained");
+if (_num_blocks[i] > 0) {
+size_t num_retire =  _indexedFreeList[i].count();
+assert(_num_blocks[i] > num_retire, "Should have used at least one");
+{
+// MutexLockerEx x(_cfls->_indexedFreeListParLocks[i],
+//                Mutex::_no_safepoint_check_flag);
+// Update globals stats for num_blocks used
+_global_num_blocks[i] += (_num_blocks[i] - num_retire);
+_global_num_workers[i]++;
+assert(_global_num_workers[i] <= ParallelGCThreads, "Too big");
+if (num_retire > 0) {
+_cfls->_indexedFreeList[i].prepend(&_indexedFreeList[i]);
+// Reset this list.
+_indexedFreeList[i] = AdaptiveFreeList<FreeChunk>();
+_indexedFreeList[i].set_size(i);
+}
+}
+if (PrintOldPLAB) {
+gclog_or_tty->print_cr("%d[" SIZE_FORMAT "]: " SIZE_FORMAT "/" SIZE_FORMAT "/" SIZE_FORMAT,
+tid, i, num_retire, _num_blocks[i], (size_t)_blocks_to_claim[i].average());
+}
+// Reset stats for next round
+_num_blocks[i]         = 0;
+}
+}
+}
+void CompactibleFreeListSpace:: par_get_chunk_of_blocks(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl) {
+assert(fl->count() == 0, "Precondition.");
+assert(word_sz < CompactibleFreeListSpace::IndexSetSize,
+"Precondition");
+// We'll try all multiples of word_sz in the indexed set, starting with
+// word_sz itself and, if CMSSplitIndexedFreeListBlocks, try larger multiples,
+// then try getting a big chunk and splitting it.
+{
+bool found;
+int  k;
+size_t cur_sz;
+for (k = 1, cur_sz = k * word_sz, found = false;
+(cur_sz < CompactibleFreeListSpace::IndexSetSize) &&
+(CMSSplitIndexedFreeListBlocks || k <= 1);
+k++, cur_sz = k * word_sz) {
+AdaptiveFreeList<FreeChunk> fl_for_cur_sz;  // Empty.
+fl_for_cur_sz.set_size(cur_sz);
+{
+MutexLockerEx x(_indexedFreeListParLocks[cur_sz],
+Mutex::_no_safepoint_check_flag);
+AdaptiveFreeList<FreeChunk>* gfl = &_indexedFreeList[cur_sz];
+if (gfl->count() != 0) {
+// nn is the number of chunks of size cur_sz that
+// we'd need to split k-ways each, in order to create
+// "n" chunks of size word_sz each.
+const size_t nn = MAX2(n/k, (size_t)1);
+gfl->getFirstNChunksFromList(nn, &fl_for_cur_sz);
+found = true;
+if (k > 1) {
+// Update split death stats for the cur_sz-size blocks list:
+// we increment the split death count by the number of blocks
+// we just took from the cur_sz-size blocks list and which
+// we will be splitting below.
+ssize_t deaths = gfl->split_deaths() +
+fl_for_cur_sz.count();
+gfl->set_split_deaths(deaths);
+}
+}
+}
+// 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.get_chunk_at_head()) != 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();
+assert(fc->is_free(), "Error");
+for (int i = k-1; i >= 0; i--) {
+FreeChunk* ffc = (FreeChunk*)((HeapWord*)fc + i * word_sz);
+assert((i != 0) ||
+((fc == ffc) && ffc->is_free() &&
+(ffc->size() == k*word_sz) && (fc_size == word_sz)),
+"Counting error");
+ffc->set_size(word_sz);
+ffc->link_prev(NULL); // Mark as a free block for other (parallel) GC threads.
+ffc->link_next(NULL);
+// Above must occur before BOT is updated below.
+OrderAccess::storestore();
+// splitting from the right, fc_size == i * word_sz
+_bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */);
+fc_size -= word_sz;
+assert(fc_size == i*word_sz, "Error");
+_bt.verify_not_unallocated((HeapWord*)ffc, word_sz);
+_bt.verify_single_block((HeapWord*)fc, fc_size);
+_bt.verify_single_block((HeapWord*)ffc, word_sz);
+// Push this on "fl".
+fl->return_chunk_at_head(ffc);
+}
+// TRAP
+assert(fl->tail()->next() == NULL, "List invariant.");
+}
+}
+// Update birth stats for this block size.
+size_t num = fl->count();
+MutexLockerEx x(_indexedFreeListParLocks[word_sz],
+Mutex::_no_safepoint_check_flag);
+ssize_t births = _indexedFreeList[word_sz].split_births() + num;
+_indexedFreeList[word_sz].set_split_births(births);
+return;
+}
+}
+}
+// 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()->get_chunk(MAX2(n * word_sz, _dictionary->min_size()),
+FreeBlockDictionary<FreeChunk>::atLeast);
+if (fc != NULL) {
+_bt.allocated((HeapWord*)fc, fc->size(), true /* reducing */);  // update _unallocated_blk
+dictionary()->dict_census_update(fc->size(),
+true /*split*/,
+false /*birth*/);
+break;
+} else {
+n--;
+}
+}
+if (fc == NULL) return;
+// Otherwise, split up that block.
+assert((ssize_t)n >= 1, "Control point invariant");
+assert(fc->is_free(), "Error: should be a free block");
+_bt.verify_single_block((HeapWord*)fc, fc->size());
+const size_t nn = fc->size() / word_sz;
+n = MIN2(nn, n);
+assert((ssize_t)n >= 1, "Control point invariant");
+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;
+}
+// Note that at this point we may have n == 0.
+assert((ssize_t)n >= 0, "Control point invariant");
+// If n is 0, the chunk fc that was found is not large
+// enough to leave a viable remainder.  We are unable to
+// allocate even one block.  Return fc to the
+// dictionary and return, leaving "fl" empty.
+if (n == 0) {
+returnChunkToDictionary(fc);
+assert(fl->count() == 0, "We never allocated any blocks");
+return;
+}
+// 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 concurrent allocation
+// 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->set_size(rem);
+rem_fc->link_prev(NULL); // Mark as a free block for other (parallel) GC threads.
+rem_fc->link_next(NULL);
+// Above must occur before BOT is updated below.
+assert((ssize_t)n > 0 && prefix_size > 0 && rem_fc > fc, "Error");
+OrderAccess::storestore();
+_bt.split_block((HeapWord*)fc, fc->size(), prefix_size);
+assert(fc->is_free(), "Error");
+fc->set_size(prefix_size);
+if (rem >= IndexSetSize) {
+returnChunkToDictionary(rem_fc);
+dictionary()->dict_census_update(rem, 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].return_chunk_at_head(rem_fc);
+smallSplitBirth(rem);
+}
+assert((ssize_t)n > 0 && fc != NULL, "Consistency");
+// 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->set_size(word_sz);
+ffc->link_prev(NULL); // Mark as a free block for other (parallel) GC threads.
+ffc->link_next(NULL);
+// Above must occur before BOT is updated below.
+OrderAccess::storestore();
+// splitting from the right, fc_size == (n - i + 1) * wordsize
+_bt.mark_block((HeapWord*)ffc, word_sz, true /* reducing */);
+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->return_chunk_at_head(ffc);
+}
+// First chunk
+assert(fc->is_free() && fc->size() == n*word_sz, "Error: should still be a free block");
+// The blocks above should show their new sizes before the first block below
+fc->set_size(word_sz);
+fc->link_prev(NULL);    // idempotent wrt free-ness, see assert above
+fc->link_next(NULL);
+_bt.verify_not_unallocated((HeapWord*)fc, fc->size());
+_bt.verify_single_block((HeapWord*)fc, fc->size());
+fl->return_chunk_at_head(fc);
+assert((ssize_t)n > 0 && (ssize_t)n == fl->count(), "Incorrect number of blocks");
+{
+// Update the stats for this block size.
+MutexLockerEx x(_indexedFreeListParLocks[word_sz],
+Mutex::_no_safepoint_check_flag);
+const ssize_t births = _indexedFreeList[word_sz].split_births() + n;
+_indexedFreeList[word_sz].set_split_births(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((n_tasks == 0) == used_region().is_empty(), "n_tasks incorrect");
+assert(n_tasks == 0 ||
+((used_region().start() + (n_tasks - 1)*task_size < used_region().end()) &&
+(used_region().start() + n_tasks*task_size >= used_region().end())),
+"n_tasks calculation incorrect");
+SequentialSubTasksDone* pst = conc_par_seq_tasks();
+assert(!pst->valid(), "Clobbering existing data?");
+// Sets the condition for completion of the subtask (how many threads
+// need to finish in order to be done).
+pst->set_n_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_tasks calculation incorrect");
+SequentialSubTasksDone* pst = conc_par_seq_tasks();
+assert(!pst->valid(), "Clobbering existing data?");
+// Sets the condition for completion of the subtask (how many threads
+// need to finish in order to be done).
+pst->set_n_threads(n_threads);
+pst->set_n_tasks((int)n_tasks);
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

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

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