graal-jvmci-8: src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp comparison

comparison src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	ba764ed4b6f2

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+:a61af66fc99e
+/*
+* Copyright 2005-2007 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+class ParallelScavengeHeap;
+class PSAdaptiveSizePolicy;
+class PSYoungGen;
+class PSOldGen;
+class PSPermGen;
+class ParCompactionManager;
+class ParallelTaskTerminator;
+class PSParallelCompact;
+class GCTaskManager;
+class GCTaskQueue;
+class PreGCValues;
+class MoveAndUpdateClosure;
+class RefProcTaskExecutor;
+class SpaceInfo
+{
+public:
+MutableSpace* space() const { return _space; }
+// Where the free space will start after the collection.  Valid only after the
+// summary phase completes.
+HeapWord* new_top() const { return _new_top; }
+// Allows new_top to be set.
+HeapWord** new_top_addr() { return &_new_top; }
+// Where the smallest allowable dense prefix ends (used only for perm gen).
+HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
+// Where the dense prefix ends, or the compacted region begins.
+HeapWord* dense_prefix() const { return _dense_prefix; }
+// The start array for the (generation containing the) space, or NULL if there
+// is no start array.
+ObjectStartArray* start_array() const { return _start_array; }
+void set_space(MutableSpace* s)           { _space = s; }
+void set_new_top(HeapWord* addr)          { _new_top = addr; }
+void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
+void set_dense_prefix(HeapWord* addr)     { _dense_prefix = addr; }
+void set_start_array(ObjectStartArray* s) { _start_array = s; }
+private:
+MutableSpace*     _space;
+HeapWord*         _new_top;
+HeapWord*         _min_dense_prefix;
+HeapWord*         _dense_prefix;
+ObjectStartArray* _start_array;
+};
+class ParallelCompactData
+{
+public:
+// Sizes are in HeapWords, unless indicated otherwise.
+static const size_t Log2ChunkSize;
+static const size_t ChunkSize;
+static const size_t ChunkSizeBytes;
+// Mask for the bits in a size_t to get an offset within a chunk.
+static const size_t ChunkSizeOffsetMask;
+// Mask for the bits in a pointer to get an offset within a chunk.
+static const size_t ChunkAddrOffsetMask;
+// Mask for the bits in a pointer to get the address of the start of a chunk.
+static const size_t ChunkAddrMask;
+static const size_t Log2BlockSize;
+static const size_t BlockSize;
+static const size_t BlockOffsetMask;
+static const size_t BlockMask;
+static const size_t BlocksPerChunk;
+class ChunkData
+{
+public:
+// Destination address of the chunk.
+HeapWord* destination() const { return _destination; }
+// The first chunk containing data destined for this chunk.
+size_t source_chunk() const { return _source_chunk; }
+// The object (if any) starting in this chunk and ending in a different
+// chunk that could not be updated during the main (parallel) compaction
+// phase.  This is different from _partial_obj_addr, which is an object that
+// extends onto a source chunk.  However, the two uses do not overlap in
+// time, so the same field is used to save space.
+HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
+// The starting address of the partial object extending onto the chunk.
+HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
+// Size of the partial object extending onto the chunk (words).
+size_t partial_obj_size() const { return _partial_obj_size; }
+// Size of live data that lies within this chunk due to objects that start
+// in this chunk (words).  This does not include the partial object
+// extending onto the chunk (if any), or the part of an object that extends
+// onto the next chunk (if any).
+size_t live_obj_size() const { return _dc_and_los & los_mask; }
+// Total live data that lies within the chunk (words).
+size_t data_size() const { return partial_obj_size() + live_obj_size(); }
+// The destination_count is the number of other chunks to which data from
+// this chunk will be copied.  At the end of the summary phase, the valid
+// values of destination_count are
+//
+// 0 - data from the chunk will be compacted completely into itself, or the
+//     chunk is empty.  The chunk can be claimed and then filled.
+// 1 - data from the chunk will be compacted into 1 other chunk; some
+//     data from the chunk may also be compacted into the chunk itself.
+// 2 - data from the chunk will be copied to 2 other chunks.
+//
+// During compaction as chunks are emptied, the destination_count is
+// decremented (atomically) and when it reaches 0, it can be claimed and
+// then filled.
+//
+// A chunk is claimed for processing by atomically changing the
+// destination_count to the claimed value (dc_claimed).  After a chunk has
+// been filled, the destination_count should be set to the completed value
+// (dc_completed).
+inline uint destination_count() const;
+inline uint destination_count_raw() const;
+// The location of the java heap data that corresponds to this chunk.
+inline HeapWord* data_location() const;
+// The highest address referenced by objects in this chunk.
+inline HeapWord* highest_ref() const;
+// Whether this chunk is available to be claimed, has been claimed, or has
+// been completed.
+//
+// Minor subtlety:  claimed() returns true if the chunk is marked
+// completed(), which is desirable since a chunk must be claimed before it
+// can be completed.
+bool available() const { return _dc_and_los < dc_one; }
+bool claimed() const   { return _dc_and_los >= dc_claimed; }
+bool completed() const { return _dc_and_los >= dc_completed; }
+// These are not atomic.
+void set_destination(HeapWord* addr)       { _destination = addr; }
+void set_source_chunk(size_t chunk)        { _source_chunk = chunk; }
+void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
+void set_partial_obj_addr(HeapWord* addr)  { _partial_obj_addr = addr; }
+void set_partial_obj_size(size_t words)    {
+_partial_obj_size = (chunk_sz_t) words;
+}
+inline void set_destination_count(uint count);
+inline void set_live_obj_size(size_t words);
+inline void set_data_location(HeapWord* addr);
+inline void set_completed();
+inline bool claim_unsafe();
+// These are atomic.
+inline void add_live_obj(size_t words);
+inline void set_highest_ref(HeapWord* addr);
+inline void decrement_destination_count();
+inline bool claim();
+private:
+// The type used to represent object sizes within a chunk.
+typedef uint chunk_sz_t;
+// Constants for manipulating the _dc_and_los field, which holds both the
+// destination count and live obj size.  The live obj size lives at the
+// least significant end so no masking is necessary when adding.
+static const chunk_sz_t dc_shift;           // Shift amount.
+static const chunk_sz_t dc_mask;            // Mask for destination count.
+static const chunk_sz_t dc_one;             // 1, shifted appropriately.
+static const chunk_sz_t dc_claimed;         // Chunk has been claimed.
+static const chunk_sz_t dc_completed;       // Chunk has been completed.
+static const chunk_sz_t los_mask;           // Mask for live obj size.
+HeapWord*           _destination;
+size_t              _source_chunk;
+HeapWord*           _partial_obj_addr;
+chunk_sz_t          _partial_obj_size;
+chunk_sz_t volatile _dc_and_los;
+#ifdef ASSERT
+// These enable optimizations that are only partially implemented.  Use
+// debug builds to prevent the code fragments from breaking.
+HeapWord*           _data_location;
+HeapWord*           _highest_ref;
+#endif  // #ifdef ASSERT
+#ifdef ASSERT
+public:
+uint            _pushed;    // 0 until chunk is pushed onto a worker's stack
+private:
+#endif
+};
+// 'Blocks' allow shorter sections of the bitmap to be searched.  Each Block
+// holds an offset, which is the amount of live data in the Chunk to the left
+// of the first live object in the Block.  This amount of live data will
+// include any object extending into the block. The first block in
+// a chunk does not include any partial object extending into the
+// the chunk.
+//
+// The offset also encodes the
+// 'parity' of the first 1 bit in the Block:  a positive offset means the
+// first 1 bit marks the start of an object, a negative offset means the first
+// 1 bit marks the end of an object.
+class BlockData
+{
+public:
+typedef short int blk_ofs_t;
+blk_ofs_t offset() const { return _offset >= 0 ? _offset : -_offset; }
+blk_ofs_t raw_offset() const { return _offset; }
+void set_first_is_start_bit(bool v) { _first_is_start_bit = v; }
+#if 0
+// The need for this method was anticipated but it is
+// never actually used.  Do not include it for now.  If
+// it is needed, consider the problem of what is passed
+// as "v".  To avoid warning errors the method set_start_bit_offset()
+// was changed to take a size_t as the parameter and to do the
+// check for the possible overflow.  Doing the cast in these
+// methods better limits the potential problems because of
+// the size of the field to this class.
+void set_raw_offset(blk_ofs_t v) { _offset = v; }
+#endif
+void set_start_bit_offset(size_t val) {
+assert(val >= 0, "sanity");
+_offset = (blk_ofs_t) val;
+assert(val == (size_t) _offset, "Value is too large");
+_first_is_start_bit = true;
+}
+void set_end_bit_offset(size_t val) {
+assert(val >= 0, "sanity");
+_offset = (blk_ofs_t) val;
+assert(val == (size_t) _offset, "Value is too large");
+_offset = - _offset;
+_first_is_start_bit = false;
+}
+bool first_is_start_bit() {
+assert(_set_phase > 0, "Not initialized");
+return _first_is_start_bit;
+}
+bool first_is_end_bit() {
+assert(_set_phase > 0, "Not initialized");
+return !_first_is_start_bit;
+}
+private:
+blk_ofs_t _offset;
+// This is temporary until the mark_bitmap is separated into
+// a start bit array and an end bit array.
+bool      _first_is_start_bit;
+#ifdef ASSERT
+short     _set_phase;
+static short _cur_phase;
+public:
+static void set_cur_phase(short v) { _cur_phase = v; }
+#endif
+};
+public:
+ParallelCompactData();
+bool initialize(MemRegion covered_region);
+size_t chunk_count() const { return _chunk_count; }
+// Convert chunk indices to/from ChunkData pointers.
+inline ChunkData* chunk(size_t chunk_idx) const;
+inline size_t     chunk(const ChunkData* const chunk_ptr) const;
+// Returns true if the given address is contained within the chunk
+bool chunk_contains(size_t chunk_index, HeapWord* addr);
+size_t block_count() const { return _block_count; }
+inline BlockData* block(size_t n) const;
+// Returns true if the given block is in the given chunk.
+static bool chunk_contains_block(size_t chunk_index, size_t block_index);
+void add_obj(HeapWord* addr, size_t len);
+void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
+// Fill in the chunks covering [beg, end) so that no data moves; i.e., the
+// destination of chunk n is simply the start of chunk n.  The argument beg
+// must be chunk-aligned; end need not be.
+void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
+bool summarize(HeapWord* target_beg, HeapWord* target_end,
+HeapWord* source_beg, HeapWord* source_end,
+HeapWord** target_next, HeapWord** source_next = 0);
+void clear();
+void clear_range(size_t beg_chunk, size_t end_chunk);
+void clear_range(HeapWord* beg, HeapWord* end) {
+clear_range(addr_to_chunk_idx(beg), addr_to_chunk_idx(end));
+}
+// Return the number of words between addr and the start of the chunk
+// containing addr.
+inline size_t     chunk_offset(const HeapWord* addr) const;
+// Convert addresses to/from a chunk index or chunk pointer.
+inline size_t     addr_to_chunk_idx(const HeapWord* addr) const;
+inline ChunkData* addr_to_chunk_ptr(const HeapWord* addr) const;
+inline HeapWord*  chunk_to_addr(size_t chunk) const;
+inline HeapWord*  chunk_to_addr(size_t chunk, size_t offset) const;
+inline HeapWord*  chunk_to_addr(const ChunkData* chunk) const;
+inline HeapWord*  chunk_align_down(HeapWord* addr) const;
+inline HeapWord*  chunk_align_up(HeapWord* addr) const;
+inline bool       is_chunk_aligned(HeapWord* addr) const;
+// Analogous to chunk_offset() for blocks.
+size_t     block_offset(const HeapWord* addr) const;
+size_t     addr_to_block_idx(const HeapWord* addr) const;
+size_t     addr_to_block_idx(const oop obj) const {
+return addr_to_block_idx((HeapWord*) obj);
+}
+inline BlockData* addr_to_block_ptr(const HeapWord* addr) const;
+inline HeapWord*  block_to_addr(size_t block) const;
+// Return the address one past the end of the partial object.
+HeapWord* partial_obj_end(size_t chunk_idx) const;
+// Return the new location of the object p after the
+// the compaction.
+HeapWord* calc_new_pointer(HeapWord* addr);
+// Same as calc_new_pointer() using blocks.
+HeapWord* block_calc_new_pointer(HeapWord* addr);
+// Same as calc_new_pointer() using chunks.
+HeapWord* chunk_calc_new_pointer(HeapWord* addr);
+HeapWord* calc_new_pointer(oop p) {
+return calc_new_pointer((HeapWord*) p);
+}
+// Return the updated address for the given klass
+klassOop calc_new_klass(klassOop);
+// Given a block returns true if the partial object for the
+// corresponding chunk ends in the block.  Returns false, otherwise
+// If there is no partial object, returns false.
+bool partial_obj_ends_in_block(size_t block_index);
+// Returns the block index for the block
+static size_t block_idx(BlockData* block);
+#ifdef  ASSERT
+void verify_clear(const PSVirtualSpace* vspace);
+void verify_clear();
+#endif  // #ifdef ASSERT
+private:
+bool initialize_block_data(size_t region_size);
+bool initialize_chunk_data(size_t region_size);
+PSVirtualSpace* create_vspace(size_t count, size_t element_size);
+private:
+HeapWord*       _region_start;
+#ifdef  ASSERT
+HeapWord*       _region_end;
+#endif  // #ifdef ASSERT
+PSVirtualSpace* _chunk_vspace;
+ChunkData*      _chunk_data;
+size_t          _chunk_count;
+PSVirtualSpace* _block_vspace;
+BlockData*      _block_data;
+size_t          _block_count;
+};
+inline uint
+ParallelCompactData::ChunkData::destination_count_raw() const
+{
+return _dc_and_los & dc_mask;
+}
+inline uint
+ParallelCompactData::ChunkData::destination_count() const
+{
+return destination_count_raw() >> dc_shift;
+}
+inline void
+ParallelCompactData::ChunkData::set_destination_count(uint count)
+{
+assert(count <= (dc_completed >> dc_shift), "count too large");
+const chunk_sz_t live_sz = (chunk_sz_t) live_obj_size();
+_dc_and_los = (count << dc_shift) | live_sz;
+}
+inline void ParallelCompactData::ChunkData::set_live_obj_size(size_t words)
+{
+assert(words <= los_mask, "would overflow");
+_dc_and_los = destination_count_raw() | (chunk_sz_t)words;
+}
+inline void ParallelCompactData::ChunkData::decrement_destination_count()
+{
+assert(_dc_and_los < dc_claimed, "already claimed");
+assert(_dc_and_los >= dc_one, "count would go negative");
+Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
+}
+inline HeapWord* ParallelCompactData::ChunkData::data_location() const
+{
+DEBUG_ONLY(return _data_location;)
+NOT_DEBUG(return NULL;)
+}
+inline HeapWord* ParallelCompactData::ChunkData::highest_ref() const
+{
+DEBUG_ONLY(return _highest_ref;)
+NOT_DEBUG(return NULL;)
+}
+inline void ParallelCompactData::ChunkData::set_data_location(HeapWord* addr)
+{
+DEBUG_ONLY(_data_location = addr;)
+}
+inline void ParallelCompactData::ChunkData::set_completed()
+{
+assert(claimed(), "must be claimed first");
+_dc_and_los = dc_completed | (chunk_sz_t) live_obj_size();
+}
+// MT-unsafe claiming of a chunk.  Should only be used during single threaded
+// execution.
+inline bool ParallelCompactData::ChunkData::claim_unsafe()
+{
+if (available()) {
+_dc_and_los |= dc_claimed;
+return true;
+}
+return false;
+}
+inline void ParallelCompactData::ChunkData::add_live_obj(size_t words)
+{
+assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
+Atomic::add((int) words, (volatile int*) &_dc_and_los);
+}
+inline void ParallelCompactData::ChunkData::set_highest_ref(HeapWord* addr)
+{
+#ifdef ASSERT
+HeapWord* tmp = _highest_ref;
+while (addr > tmp) {
+tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
+}
+#endif  // #ifdef ASSERT
+}
+inline bool ParallelCompactData::ChunkData::claim()
+{
+const int los = (int) live_obj_size();
+const int old = Atomic::cmpxchg(dc_claimed | los,
+(volatile int*) &_dc_and_los, los);
+return old == los;
+}
+inline ParallelCompactData::ChunkData*
+ParallelCompactData::chunk(size_t chunk_idx) const
+{
+assert(chunk_idx <= chunk_count(), "bad arg");
+return _chunk_data + chunk_idx;
+}
+inline size_t
+ParallelCompactData::chunk(const ChunkData* const chunk_ptr) const
+{
+assert(chunk_ptr >= _chunk_data, "bad arg");
+assert(chunk_ptr <= _chunk_data + chunk_count(), "bad arg");
+return pointer_delta(chunk_ptr, _chunk_data, sizeof(ChunkData));
+}
+inline ParallelCompactData::BlockData*
+ParallelCompactData::block(size_t n) const {
+assert(n < block_count(), "bad arg");
+return _block_data + n;
+}
+inline size_t
+ParallelCompactData::chunk_offset(const HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr <= _region_end, "bad addr");
+return (size_t(addr) & ChunkAddrOffsetMask) >> LogHeapWordSize;
+}
+inline size_t
+ParallelCompactData::addr_to_chunk_idx(const HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr <= _region_end, "bad addr");
+return pointer_delta(addr, _region_start) >> Log2ChunkSize;
+}
+inline ParallelCompactData::ChunkData*
+ParallelCompactData::addr_to_chunk_ptr(const HeapWord* addr) const
+{
+return chunk(addr_to_chunk_idx(addr));
+}
+inline HeapWord*
+ParallelCompactData::chunk_to_addr(size_t chunk) const
+{
+assert(chunk <= _chunk_count, "chunk out of range");
+return _region_start + (chunk << Log2ChunkSize);
+}
+inline HeapWord*
+ParallelCompactData::chunk_to_addr(const ChunkData* chunk) const
+{
+return chunk_to_addr(pointer_delta(chunk, _chunk_data, sizeof(ChunkData)));
+}
+inline HeapWord*
+ParallelCompactData::chunk_to_addr(size_t chunk, size_t offset) const
+{
+assert(chunk <= _chunk_count, "chunk out of range");
+assert(offset < ChunkSize, "offset too big");  // This may be too strict.
+return chunk_to_addr(chunk) + offset;
+}
+inline HeapWord*
+ParallelCompactData::chunk_align_down(HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr < _region_end + ChunkSize, "bad addr");
+return (HeapWord*)(size_t(addr) & ChunkAddrMask);
+}
+inline HeapWord*
+ParallelCompactData::chunk_align_up(HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr <= _region_end, "bad addr");
+return chunk_align_down(addr + ChunkSizeOffsetMask);
+}
+inline bool
+ParallelCompactData::is_chunk_aligned(HeapWord* addr) const
+{
+return chunk_offset(addr) == 0;
+}
+inline size_t
+ParallelCompactData::block_offset(const HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr <= _region_end, "bad addr");
+return pointer_delta(addr, _region_start) & BlockOffsetMask;
+}
+inline size_t
+ParallelCompactData::addr_to_block_idx(const HeapWord* addr) const
+{
+assert(addr >= _region_start, "bad addr");
+assert(addr <= _region_end, "bad addr");
+return pointer_delta(addr, _region_start) >> Log2BlockSize;
+}
+inline ParallelCompactData::BlockData*
+ParallelCompactData::addr_to_block_ptr(const HeapWord* addr) const
+{
+return block(addr_to_block_idx(addr));
+}
+inline HeapWord*
+ParallelCompactData::block_to_addr(size_t block) const
+{
+assert(block < _block_count, "block out of range");
+return _region_start + (block << Log2BlockSize);
+}
+// Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
+// do_addr() method.
+//
+// The closure is initialized with the number of heap words to process
+// (words_remaining()), and becomes 'full' when it reaches 0.  The do_addr()
+// methods in subclasses should update the total as words are processed.  Since
+// only one subclass actually uses this mechanism to terminate iteration, the
+// default initial value is > 0.  The implementation is here and not in the
+// single subclass that uses it to avoid making is_full() virtual, and thus
+// adding a virtual call per live object.
+class ParMarkBitMapClosure: public StackObj {
+public:
+typedef ParMarkBitMap::idx_t idx_t;
+typedef ParMarkBitMap::IterationStatus IterationStatus;
+public:
+inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
+size_t words = max_uintx);
+inline ParCompactionManager* compaction_manager() const;
+inline ParMarkBitMap*        bitmap() const;
+inline size_t                words_remaining() const;
+inline bool                  is_full() const;
+inline HeapWord*             source() const;
+inline void                  set_source(HeapWord* addr);
+virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
+protected:
+inline void decrement_words_remaining(size_t words);
+private:
+ParMarkBitMap* const        _bitmap;
+ParCompactionManager* const _compaction_manager;
+DEBUG_ONLY(const size_t     _initial_words_remaining;) // Useful in debugger.
+size_t                      _words_remaining; // Words left to copy.
+protected:
+HeapWord*                   _source;          // Next addr that would be read.
+};
+inline
+ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
+ParCompactionManager* cm,
+size_t words):
+_bitmap(bitmap), _compaction_manager(cm)
+#ifdef  ASSERT
+, _initial_words_remaining(words)
+#endif
+{
+_words_remaining = words;
+_source = NULL;
+}
+inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
+return _compaction_manager;
+}
+inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
+return _bitmap;
+}
+inline size_t ParMarkBitMapClosure::words_remaining() const {
+return _words_remaining;
+}
+inline bool ParMarkBitMapClosure::is_full() const {
+return words_remaining() == 0;
+}
+inline HeapWord* ParMarkBitMapClosure::source() const {
+return _source;
+}
+inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
+_source = addr;
+}
+inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
+assert(_words_remaining >= words, "processed too many words");
+_words_remaining -= words;
+}
+// Closure for updating the block data during the summary phase.
+class BitBlockUpdateClosure: public ParMarkBitMapClosure {
+// ParallelCompactData::BlockData::blk_ofs_t _live_data_left;
+size_t    _live_data_left;
+size_t    _cur_block;
+HeapWord* _chunk_start;
+HeapWord* _chunk_end;
+size_t    _chunk_index;
+public:
+BitBlockUpdateClosure(ParMarkBitMap* mbm,
+ParCompactionManager* cm,
+size_t chunk_index);
+size_t cur_block() { return _cur_block; }
+size_t chunk_index() { return _chunk_index; }
+size_t live_data_left() { return _live_data_left; }
+// Returns true the first bit in the current block (cur_block) is
+// a start bit.
+// Returns true if the current block is within the chunk for the closure;
+bool chunk_contains_cur_block();
+// Set the chunk index and related chunk values for
+// a new chunk.
+void reset_chunk(size_t chunk_index);
+virtual IterationStatus do_addr(HeapWord* addr, size_t words);
+};
+class PSParallelCompact : AllStatic {
+public:
+// Convenient access to type names.
+typedef ParMarkBitMap::idx_t idx_t;
+typedef ParallelCompactData::ChunkData ChunkData;
+typedef ParallelCompactData::BlockData BlockData;
+typedef enum {
+perm_space_id, old_space_id, eden_space_id,
+from_space_id, to_space_id, last_space_id
+} SpaceId;
+public:
+// In line closure decls
+//
+class IsAliveClosure: public BoolObjectClosure {
+public:
+void do_object(oop p) { assert(false, "don't call"); }
+bool do_object_b(oop p) { return mark_bitmap()->is_marked(p); }
+};
+class KeepAliveClosure: public OopClosure {
+ParCompactionManager* _compaction_manager;
+public:
+KeepAliveClosure(ParCompactionManager* cm) {
+_compaction_manager = cm;
+}
+void do_oop(oop* p);
+};
+class FollowRootClosure: public OopsInGenClosure{
+ParCompactionManager* _compaction_manager;
+public:
+FollowRootClosure(ParCompactionManager* cm) {
+_compaction_manager = cm;
+}
+void do_oop(oop* p) { follow_root(_compaction_manager, p); }
+virtual const bool do_nmethods() const { return true; }
+};
+class FollowStackClosure: public VoidClosure {
+ParCompactionManager* _compaction_manager;
+public:
+FollowStackClosure(ParCompactionManager* cm) {
+_compaction_manager = cm;
+}
+void do_void() { follow_stack(_compaction_manager); }
+};
+class AdjustPointerClosure: public OopsInGenClosure {
+bool _is_root;
+public:
+AdjustPointerClosure(bool is_root) : _is_root(is_root) {}
+void do_oop(oop* p) { adjust_pointer(p, _is_root); }
+};
+// Closure for verifying update of pointers.  Does not
+// have any side effects.
+class VerifyUpdateClosure: public ParMarkBitMapClosure {
+const MutableSpace* _space; // Is this ever used?
+public:
+VerifyUpdateClosure(ParCompactionManager* cm, const MutableSpace* sp) :
+ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm), _space(sp)
+{ }
+virtual IterationStatus do_addr(HeapWord* addr, size_t words);
+const MutableSpace* space() { return _space; }
+};
+// Closure for updating objects altered for debug checking
+class ResetObjectsClosure: public ParMarkBitMapClosure {
+public:
+ResetObjectsClosure(ParCompactionManager* cm):
+ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm)
+{ }
+virtual IterationStatus do_addr(HeapWord* addr, size_t words);
+};
+friend class KeepAliveClosure;
+friend class FollowStackClosure;
+friend class AdjustPointerClosure;
+friend class FollowRootClosure;
+friend class instanceKlassKlass;
+friend class RefProcTaskProxy;
+static void mark_and_push_internal(ParCompactionManager* cm, oop* p);
+private:
+static elapsedTimer         _accumulated_time;
+static unsigned int         _total_invocations;
+static unsigned int         _maximum_compaction_gc_num;
+static jlong                _time_of_last_gc;   // ms
+static CollectorCounters*   _counters;
+static ParMarkBitMap        _mark_bitmap;
+static ParallelCompactData  _summary_data;
+static IsAliveClosure       _is_alive_closure;
+static SpaceInfo            _space_info[last_space_id];
+static bool                 _print_phases;
+static AdjustPointerClosure _adjust_root_pointer_closure;
+static AdjustPointerClosure _adjust_pointer_closure;
+// Reference processing (used in ...follow_contents)
+static ReferenceProcessor*  _ref_processor;
+// Updated location of intArrayKlassObj.
+static klassOop _updated_int_array_klass_obj;
+// Values computed at initialization and used by dead_wood_limiter().
+static double _dwl_mean;
+static double _dwl_std_dev;
+static double _dwl_first_term;
+static double _dwl_adjustment;
+#ifdef  ASSERT
+static bool   _dwl_initialized;
+#endif  // #ifdef ASSERT
+private:
+// Closure accessors
+static OopClosure* adjust_pointer_closure() { return (OopClosure*)&_adjust_pointer_closure; }
+static OopClosure* adjust_root_pointer_closure() { return (OopClosure*)&_adjust_root_pointer_closure; }
+static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; }
+static void initialize_space_info();
+// Return true if details about individual phases should be printed.
+static inline bool print_phases();
+// Clear the marking bitmap and summary data that cover the specified space.
+static void clear_data_covering_space(SpaceId id);
+static void pre_compact(PreGCValues* pre_gc_values);
+static void post_compact();
+// Mark live objects
+static void marking_phase(ParCompactionManager* cm,
+bool maximum_heap_compaction);
+static void follow_stack(ParCompactionManager* cm);
+static void follow_weak_klass_links(ParCompactionManager* cm);
+static void adjust_pointer(oop* p, bool is_root);
+static void adjust_root_pointer(oop* p) { adjust_pointer(p, true); }
+static void follow_root(ParCompactionManager* cm, oop* p);
+// Compute the dense prefix for the designated space.  This is an experimental
+// implementation currently not used in production.
+static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
+bool maximum_compaction);
+// Methods used to compute the dense prefix.
+// Compute the value of the normal distribution at x = density.  The mean and
+// standard deviation are values saved by initialize_dead_wood_limiter().
+static inline double normal_distribution(double density);
+// Initialize the static vars used by dead_wood_limiter().
+static void initialize_dead_wood_limiter();
+// Return the percentage of space that can be treated as "dead wood" (i.e.,
+// not reclaimed).
+static double dead_wood_limiter(double density, size_t min_percent);
+// Find the first (left-most) chunk in the range [beg, end) that has at least
+// dead_words of dead space to the left.  The argument beg must be the first
+// chunk in the space that is not completely live.
+static ChunkData* dead_wood_limit_chunk(const ChunkData* beg,
+const ChunkData* end,
+size_t dead_words);
+// Return a pointer to the first chunk in the range [beg, end) that is not
+// completely full.
+static ChunkData* first_dead_space_chunk(const ChunkData* beg,
+const ChunkData* end);
+// Return a value indicating the benefit or 'yield' if the compacted region
+// were to start (or equivalently if the dense prefix were to end) at the
+// candidate chunk.  Higher values are better.
+//
+// The value is based on the amount of space reclaimed vs. the costs of (a)
+// updating references in the dense prefix plus (b) copying objects and
+// updating references in the compacted region.
+static inline double reclaimed_ratio(const ChunkData* const candidate,
+HeapWord* const bottom,
+HeapWord* const top,
+HeapWord* const new_top);
+// Compute the dense prefix for the designated space.
+static HeapWord* compute_dense_prefix(const SpaceId id,
+bool maximum_compaction);
+// Return true if dead space crosses onto the specified Chunk; bit must be the
+// bit index corresponding to the first word of the Chunk.
+static inline bool dead_space_crosses_boundary(const ChunkData* chunk,
+idx_t bit);
+// Summary phase utility routine to fill dead space (if any) at the dense
+// prefix boundary.  Should only be called if the the dense prefix is
+// non-empty.
+static void fill_dense_prefix_end(SpaceId id);
+static void summarize_spaces_quick();
+static void summarize_space(SpaceId id, bool maximum_compaction);
+static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
+static bool block_first_offset(size_t block_index, idx_t* block_offset_ptr);
+// Fill in the BlockData
+static void summarize_blocks(ParCompactionManager* cm,
+SpaceId first_compaction_space_id);
+// The space that is compacted after space_id.
+static SpaceId next_compaction_space_id(SpaceId space_id);
+// Adjust addresses in roots.  Does not adjust addresses in heap.
+static void adjust_roots();
+// Serial code executed in preparation for the compaction phase.
+static void compact_prologue();
+// Move objects to new locations.
+static void compact_perm(ParCompactionManager* cm);
+static void compact();
+// Add available chunks to the stack and draining tasks to the task queue.
+static void enqueue_chunk_draining_tasks(GCTaskQueue* q,
+uint parallel_gc_threads);
+// Add dense prefix update tasks to the task queue.
+static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
+uint parallel_gc_threads);
+// Add chunk stealing tasks to the task queue.
+static void enqueue_chunk_stealing_tasks(
+GCTaskQueue* q,
+ParallelTaskTerminator* terminator_ptr,
+uint parallel_gc_threads);
+// For debugging only - compacts the old gen serially
+static void compact_serial(ParCompactionManager* cm);
+// If objects are left in eden after a collection, try to move the boundary
+// and absorb them into the old gen.  Returns true if eden was emptied.
+static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
+PSYoungGen* young_gen,
+PSOldGen* old_gen);
+// Reset time since last full gc
+static void reset_millis_since_last_gc();
+protected:
+#ifdef VALIDATE_MARK_SWEEP
+static GrowableArray<oop*>*            _root_refs_stack;
+static GrowableArray<oop> *            _live_oops;
+static GrowableArray<oop> *            _live_oops_moved_to;
+static GrowableArray<size_t>*          _live_oops_size;
+static size_t                          _live_oops_index;
+static size_t                          _live_oops_index_at_perm;
+static GrowableArray<oop*>*            _other_refs_stack;
+static GrowableArray<oop*>*            _adjusted_pointers;
+static bool                            _pointer_tracking;
+static bool                            _root_tracking;
+// The following arrays are saved since the time of the last GC and
+// assist in tracking down problems where someone has done an errant
+// store into the heap, usually to an oop that wasn't properly
+// handleized across a GC. If we crash or otherwise fail before the
+// next GC, we can query these arrays to find out the object we had
+// intended to do the store to (assuming it is still alive) and the
+// offset within that object. Covered under RecordMarkSweepCompaction.
+static GrowableArray<HeapWord*> *      _cur_gc_live_oops;
+static GrowableArray<HeapWord*> *      _cur_gc_live_oops_moved_to;
+static GrowableArray<size_t>*          _cur_gc_live_oops_size;
+static GrowableArray<HeapWord*> *      _last_gc_live_oops;
+static GrowableArray<HeapWord*> *      _last_gc_live_oops_moved_to;
+static GrowableArray<size_t>*          _last_gc_live_oops_size;
+#endif
+public:
+class MarkAndPushClosure: public OopClosure {
+ParCompactionManager* _compaction_manager;
+public:
+MarkAndPushClosure(ParCompactionManager* cm) {
+_compaction_manager = cm;
+}
+void do_oop(oop* p) { mark_and_push(_compaction_manager, p); }
+virtual const bool do_nmethods() const { return true; }
+};
+PSParallelCompact();
+// Convenient accessor for Universe::heap().
+static ParallelScavengeHeap* gc_heap() {
+return (ParallelScavengeHeap*)Universe::heap();
+}
+static void invoke(bool maximum_heap_compaction);
+static void invoke_no_policy(bool maximum_heap_compaction);
+static void post_initialize();
+// Perform initialization for PSParallelCompact that requires
+// allocations.  This should be called during the VM initialization
+// at a pointer where it would be appropriate to return a JNI_ENOMEM
+// in the event of a failure.
+static bool initialize();
+// Public accessors
+static elapsedTimer* accumulated_time() { return &_accumulated_time; }
+static unsigned int total_invocations() { return _total_invocations; }
+static CollectorCounters* counters()    { return _counters; }
+// Used to add tasks
+static GCTaskManager* const gc_task_manager();
+static klassOop updated_int_array_klass_obj() {
+return _updated_int_array_klass_obj;
+}
+// Marking support
+static inline bool mark_obj(oop obj);
+static bool mark_obj(oop* p)  {
+if (*p != NULL) {
+return mark_obj(*p);
+} else {
+return false;
+}
+}
+static void mark_and_push(ParCompactionManager* cm, oop* p) {
+// Check mark and maybe push on
+// marking stack
+oop m = *p;
+if (m != NULL && mark_bitmap()->is_unmarked(m)) {
+mark_and_push_internal(cm, p);
+}
+}
+// Compaction support.
+// Return true if p is in the range [beg_addr, end_addr).
+static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
+static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
+// Convenience wrappers for per-space data kept in _space_info.
+static inline MutableSpace*     space(SpaceId space_id);
+static inline HeapWord*         new_top(SpaceId space_id);
+static inline HeapWord*         dense_prefix(SpaceId space_id);
+static inline ObjectStartArray* start_array(SpaceId space_id);
+// Return true if the klass should be updated.
+static inline bool should_update_klass(klassOop k);
+// Move and update the live objects in the specified space.
+static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
+// Process the end of the given chunk range in the dense prefix.
+// This includes saving any object not updated.
+static void dense_prefix_chunks_epilogue(ParCompactionManager* cm,
+size_t chunk_start_index,
+size_t chunk_end_index,
+idx_t exiting_object_offset,
+idx_t chunk_offset_start,
+idx_t chunk_offset_end);
+// Update a chunk in the dense prefix.  For each live object
+// in the chunk, update it's interior references.  For each
+// dead object, fill it with deadwood. Dead space at the end
+// of a chunk range will be filled to the start of the next
+// live object regardless of the chunk_index_end.  None of the
+// objects in the dense prefix move and dead space is dead
+// (holds only dead objects that don't need any processing), so
+// dead space can be filled in any order.
+static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
+SpaceId space_id,
+size_t chunk_index_start,
+size_t chunk_index_end);
+// Return the address of the count + 1st live word in the range [beg, end).
+static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
+// Return the address of the word to be copied to dest_addr, which must be
+// aligned to a chunk boundary.
+static HeapWord* first_src_addr(HeapWord* const dest_addr,
+size_t src_chunk_idx);
+// Determine the next source chunk, set closure.source() to the start of the
+// new chunk return the chunk index.  Parameter end_addr is the address one
+// beyond the end of source range just processed.  If necessary, switch to a
+// new source space and set src_space_id (in-out parameter) and src_space_top
+// (out parameter) accordingly.
+static size_t next_src_chunk(MoveAndUpdateClosure& closure,
+SpaceId& src_space_id,
+HeapWord*& src_space_top,
+HeapWord* end_addr);
+// Decrement the destination count for each non-empty source chunk in the
+// range [beg_chunk, chunk(chunk_align_up(end_addr))).
+static void decrement_destination_counts(ParCompactionManager* cm,
+size_t beg_chunk,
+HeapWord* end_addr);
+// Fill a chunk, copying objects from one or more source chunks.
+static void fill_chunk(ParCompactionManager* cm, size_t chunk_idx);
+static void fill_and_update_chunk(ParCompactionManager* cm, size_t chunk) {
+fill_chunk(cm, chunk);
+}
+// Update the deferred objects in the space.
+static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
+// Mark pointer and follow contents.
+static void mark_and_follow(ParCompactionManager* cm, oop* p);
+static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
+static ParallelCompactData& summary_data() { return _summary_data; }
+static inline void adjust_pointer(oop* p) { adjust_pointer(p, false); }
+static inline void adjust_pointer(oop* p,
+HeapWord* beg_addr,
+HeapWord* end_addr);
+// Reference Processing
+static ReferenceProcessor* const ref_processor() { return _ref_processor; }
+// Return the SpaceId for the given address.
+static SpaceId space_id(HeapWord* addr);
+// Time since last full gc (in milliseconds).
+static jlong millis_since_last_gc();
+#ifdef VALIDATE_MARK_SWEEP
+static void track_adjusted_pointer(oop* p, oop newobj, bool isroot);
+static void check_adjust_pointer(oop* p);     // Adjust this pointer
+static void track_interior_pointers(oop obj);
+static void check_interior_pointers();
+static void reset_live_oop_tracking(bool at_perm);
+static void register_live_oop(oop p, size_t size);
+static void validate_live_oop(oop p, size_t size);
+static void live_oop_moved_to(HeapWord* q, size_t size, HeapWord* compaction_top);
+static void compaction_complete();
+// Querying operation of RecordMarkSweepCompaction results.
+// Finds and prints the current base oop and offset for a word
+// within an oop that was live during the last GC. Helpful for
+// tracking down heap stomps.
+static void print_new_location_of_heap_address(HeapWord* q);
+#endif  // #ifdef VALIDATE_MARK_SWEEP
+// Call backs for class unloading
+// Update subklass/sibling/implementor links at end of marking.
+static void revisit_weak_klass_link(ParCompactionManager* cm, Klass* k);
+#ifndef PRODUCT
+// Debugging support.
+static const char* space_names[last_space_id];
+static void print_chunk_ranges();
+static void print_dense_prefix_stats(const char* const algorithm,
+const SpaceId id,
+const bool maximum_compaction,
+HeapWord* const addr);
+#endif  // #ifndef PRODUCT
+#ifdef  ASSERT
+// Verify that all the chunks have been emptied.
+static void verify_complete(SpaceId space_id);
+#endif  // #ifdef ASSERT
+};
+bool PSParallelCompact::mark_obj(oop obj) {
+const int obj_size = obj->size();
+if (mark_bitmap()->mark_obj(obj, obj_size)) {
+_summary_data.add_obj(obj, obj_size);
+return true;
+} else {
+return false;
+}
+}
+inline bool PSParallelCompact::print_phases()
+{
+return _print_phases;
+}
+inline double PSParallelCompact::normal_distribution(double density)
+{
+assert(_dwl_initialized, "uninitialized");
+const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
+return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
+}
+inline bool
+PSParallelCompact::dead_space_crosses_boundary(const ChunkData* chunk,
+idx_t bit)
+{
+assert(bit > 0, "cannot call this for the first bit/chunk");
+assert(_summary_data.chunk_to_addr(chunk) == _mark_bitmap.bit_to_addr(bit),
+"sanity check");
+// Dead space crosses the boundary if (1) a partial object does not extend
+// onto the chunk, (2) an object does not start at the beginning of the chunk,
+// and (3) an object does not end at the end of the prior chunk.
+return chunk->partial_obj_size() == 0 &&
+!_mark_bitmap.is_obj_beg(bit) &&
+!_mark_bitmap.is_obj_end(bit - 1);
+}
+inline bool
+PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
+return p >= beg_addr && p < end_addr;
+}
+inline bool
+PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
+return is_in((HeapWord*)p, beg_addr, end_addr);
+}
+inline MutableSpace* PSParallelCompact::space(SpaceId id) {
+assert(id < last_space_id, "id out of range");
+return _space_info[id].space();
+}
+inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
+assert(id < last_space_id, "id out of range");
+return _space_info[id].new_top();
+}
+inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
+assert(id < last_space_id, "id out of range");
+return _space_info[id].dense_prefix();
+}
+inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
+assert(id < last_space_id, "id out of range");
+return _space_info[id].start_array();
+}
+inline bool PSParallelCompact::should_update_klass(klassOop k) {
+return ((HeapWord*) k) >= dense_prefix(perm_space_id);
+}
+inline void PSParallelCompact::adjust_pointer(oop* p,
+HeapWord* beg_addr,
+HeapWord* end_addr) {
+if (is_in(p, beg_addr, end_addr)) {
+adjust_pointer(p);
+}
+}
+class MoveAndUpdateClosure: public ParMarkBitMapClosure {
+public:
+inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
+ObjectStartArray* start_array,
+HeapWord* destination, size_t words);
+// Accessors.
+HeapWord* destination() const         { return _destination; }
+// If the object will fit (size <= words_remaining()), copy it to the current
+// destination, update the interior oops and the start array and return either
+// full (if the closure is full) or incomplete.  If the object will not fit,
+// return would_overflow.
+virtual IterationStatus do_addr(HeapWord* addr, size_t size);
+// Copy enough words to fill this closure, starting at source().  Interior
+// oops and the start array are not updated.  Return full.
+IterationStatus copy_until_full();
+// Copy enough words to fill this closure or to the end of an object,
+// whichever is smaller, starting at source().  Interior oops and the start
+// array are not updated.
+void copy_partial_obj();
+protected:
+// Update variables to indicate that word_count words were processed.
+inline void update_state(size_t word_count);
+protected:
+ObjectStartArray* const _start_array;
+HeapWord*               _destination;         // Next addr to be written.
+};
+inline
+MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
+ParCompactionManager* cm,
+ObjectStartArray* start_array,
+HeapWord* destination,
+size_t words) :
+ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
+{
+_destination = destination;
+}
+inline void MoveAndUpdateClosure::update_state(size_t words)
+{
+decrement_words_remaining(words);
+_source += words;
+_destination += words;
+}
+class UpdateOnlyClosure: public ParMarkBitMapClosure {
+private:
+const PSParallelCompact::SpaceId _space_id;
+ObjectStartArray* const          _start_array;
+public:
+UpdateOnlyClosure(ParMarkBitMap* mbm,
+ParCompactionManager* cm,
+PSParallelCompact::SpaceId space_id);
+// Update the object.
+virtual IterationStatus do_addr(HeapWord* addr, size_t words);
+inline void do_addr(HeapWord* addr);
+};
+inline void UpdateOnlyClosure::do_addr(HeapWord* addr) {
+_start_array->allocate_block(addr);
+oop(addr)->update_contents(compaction_manager());
+}
+class FillClosure: public ParMarkBitMapClosure {
+public:
+FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id):
+ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
+_space_id(space_id),
+_start_array(PSParallelCompact::start_array(space_id))
+{
+assert(_space_id == PSParallelCompact::perm_space_id ||
+_space_id == PSParallelCompact::old_space_id,
+"cannot use FillClosure in the young gen");
+assert(bitmap() != NULL, "need a bitmap");
+assert(_start_array != NULL, "need a start array");
+}
+void fill_region(HeapWord* addr, size_t size) {
+MemRegion region(addr, size);
+SharedHeap::fill_region_with_object(region);
+_start_array->allocate_block(addr);
+}
+virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
+fill_region(addr, size);
+return ParMarkBitMap::incomplete;
+}
+private:
+const PSParallelCompact::SpaceId _space_id;
+ObjectStartArray* const          _start_array;
+};

Mercurial > hg > graal-jvmci-8

comparison src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.hpp @ 0:a61af66fc99e jdk7-b24