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src/share/vm/gc_implementation/parNew/parNewGeneration.cpp@0fbdb4381b99 (annotated)

src/share/vm/gc_implementation/parNew/parNewGeneration.cpp

Mon, 09 Mar 2009 13:28:46 -0700

author

xdono

date

Mon, 09 Mar 2009 13:28:46 -0700

changeset 1014

0fbdb4381b99

parent 969

5cfd8d19e546

child 1114

cea947c8a988

permissions

-rw-r--r--

6814575: Update copyright year
Summary: Update copyright for files that have been modified in 2009, up to 03/09
Reviewed-by: katleman, tbell, ohair

duke@435	1	/*
xdono@1014	2	* Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	# include "incls/_precompiled.incl"
duke@435	26	# include "incls/_parNewGeneration.cpp.incl"
duke@435	27
duke@435	28	#ifdef _MSC_VER
duke@435	29	#pragma warning( push )
duke@435	30	#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
duke@435	31	#endif
duke@435	32	ParScanThreadState::ParScanThreadState(Space* to_space_,
duke@435	33	ParNewGeneration* gen_,
duke@435	34	Generation* old_gen_,
duke@435	35	int thread_num_,
duke@435	36	ObjToScanQueueSet* work_queue_set_,
duke@435	37	size_t desired_plab_sz_,
duke@435	38	ParallelTaskTerminator& term_) :
duke@435	39	_to_space(to_space_), _old_gen(old_gen_), _thread_num(thread_num_),
duke@435	40	_work_queue(work_queue_set_->queue(thread_num_)), _to_space_full(false),
duke@435	41	_ageTable(false), // false ==> not the global age table, no perf data.
duke@435	42	_to_space_alloc_buffer(desired_plab_sz_),
duke@435	43	_to_space_closure(gen_, this), _old_gen_closure(gen_, this),
duke@435	44	_to_space_root_closure(gen_, this), _old_gen_root_closure(gen_, this),
duke@435	45	_older_gen_closure(gen_, this),
duke@435	46	_evacuate_followers(this, &_to_space_closure, &_old_gen_closure,
duke@435	47	&_to_space_root_closure, gen_, &_old_gen_root_closure,
duke@435	48	work_queue_set_, &term_),
duke@435	49	_is_alive_closure(gen_), _scan_weak_ref_closure(gen_, this),
duke@435	50	_keep_alive_closure(&_scan_weak_ref_closure),
duke@435	51	_pushes(0), _pops(0), _steals(0), _steal_attempts(0), _term_attempts(0),
duke@435	52	_strong_roots_time(0.0), _term_time(0.0)
duke@435	53	{
duke@435	54	_survivor_chunk_array =
duke@435	55	(ChunkArray*) old_gen()->get_data_recorder(thread_num());
duke@435	56	_hash_seed = 17; // Might want to take time-based random value.
duke@435	57	_start = os::elapsedTime();
duke@435	58	_old_gen_closure.set_generation(old_gen_);
duke@435	59	_old_gen_root_closure.set_generation(old_gen_);
duke@435	60	}
duke@435	61	#ifdef _MSC_VER
duke@435	62	#pragma warning( pop )
duke@435	63	#endif
duke@435	64
duke@435	65	void ParScanThreadState::record_survivor_plab(HeapWord* plab_start,
duke@435	66	size_t plab_word_size) {
duke@435	67	ChunkArray* sca = survivor_chunk_array();
duke@435	68	if (sca != NULL) {
duke@435	69	// A non-null SCA implies that we want the PLAB data recorded.
duke@435	70	sca->record_sample(plab_start, plab_word_size);
duke@435	71	}
duke@435	72	}
duke@435	73
duke@435	74	bool ParScanThreadState::should_be_partially_scanned(oop new_obj, oop old_obj) const {
duke@435	75	return new_obj->is_objArray() &&
duke@435	76	arrayOop(new_obj)->length() > ParGCArrayScanChunk &&
duke@435	77	new_obj != old_obj;
duke@435	78	}
duke@435	79
duke@435	80	void ParScanThreadState::scan_partial_array_and_push_remainder(oop old) {
duke@435	81	assert(old->is_objArray(), "must be obj array");
duke@435	82	assert(old->is_forwarded(), "must be forwarded");
duke@435	83	assert(Universe::heap()->is_in_reserved(old), "must be in heap.");
duke@435	84	assert(!_old_gen->is_in(old), "must be in young generation.");
duke@435	85
duke@435	86	objArrayOop obj = objArrayOop(old->forwardee());
duke@435	87	// Process ParGCArrayScanChunk elements now
duke@435	88	// and push the remainder back onto queue
duke@435	89	int start = arrayOop(old)->length();
duke@435	90	int end = obj->length();
duke@435	91	int remainder = end - start;
duke@435	92	assert(start <= end, "just checking");
duke@435	93	if (remainder > 2 * ParGCArrayScanChunk) {
duke@435	94	// Test above combines last partial chunk with a full chunk
duke@435	95	end = start + ParGCArrayScanChunk;
duke@435	96	arrayOop(old)->set_length(end);
duke@435	97	// Push remainder.
duke@435	98	bool ok = work_queue()->push(old);
duke@435	99	assert(ok, "just popped, push must be okay");
duke@435	100	note_push();
duke@435	101	} else {
duke@435	102	// Restore length so that it can be used if there
duke@435	103	// is a promotion failure and forwarding pointers
duke@435	104	// must be removed.
duke@435	105	arrayOop(old)->set_length(end);
duke@435	106	}
coleenp@548	107
duke@435	108	// process our set of indices (include header in first chunk)
coleenp@548	109	// should make sure end is even (aligned to HeapWord in case of compressed oops)
duke@435	110	if ((HeapWord *)obj < young_old_boundary()) {
duke@435	111	// object is in to_space
coleenp@548	112	obj->oop_iterate_range(&_to_space_closure, start, end);
duke@435	113	} else {
duke@435	114	// object is in old generation
coleenp@548	115	obj->oop_iterate_range(&_old_gen_closure, start, end);
duke@435	116	}
duke@435	117	}
duke@435	118
duke@435	119
duke@435	120	void ParScanThreadState::trim_queues(int max_size) {
duke@435	121	ObjToScanQueue* queue = work_queue();
duke@435	122	while (queue->size() > (juint)max_size) {
duke@435	123	oop obj_to_scan;
duke@435	124	if (queue->pop_local(obj_to_scan)) {
duke@435	125	note_pop();
duke@435	126
duke@435	127	if ((HeapWord *)obj_to_scan < young_old_boundary()) {
duke@435	128	if (obj_to_scan->is_objArray() &&
duke@435	129	obj_to_scan->is_forwarded() &&
duke@435	130	obj_to_scan->forwardee() != obj_to_scan) {
duke@435	131	scan_partial_array_and_push_remainder(obj_to_scan);
duke@435	132	} else {
duke@435	133	// object is in to_space
duke@435	134	obj_to_scan->oop_iterate(&_to_space_closure);
duke@435	135	}
duke@435	136	} else {
duke@435	137	// object is in old generation
duke@435	138	obj_to_scan->oop_iterate(&_old_gen_closure);
duke@435	139	}
duke@435	140	}
duke@435	141	}
duke@435	142	}
duke@435	143
duke@435	144	HeapWord* ParScanThreadState::alloc_in_to_space_slow(size_t word_sz) {
duke@435	145
duke@435	146	// Otherwise, if the object is small enough, try to reallocate the
duke@435	147	// buffer.
duke@435	148	HeapWord* obj = NULL;
duke@435	149	if (!_to_space_full) {
duke@435	150	ParGCAllocBuffer* const plab = to_space_alloc_buffer();
duke@435	151	Space* const sp = to_space();
duke@435	152	if (word_sz * 100 <
duke@435	153	ParallelGCBufferWastePct * plab->word_sz()) {
duke@435	154	// Is small enough; abandon this buffer and start a new one.
duke@435	155	plab->retire(false, false);
duke@435	156	size_t buf_size = plab->word_sz();
duke@435	157	HeapWord* buf_space = sp->par_allocate(buf_size);
duke@435	158	if (buf_space == NULL) {
duke@435	159	const size_t min_bytes =
duke@435	160	ParGCAllocBuffer::min_size() << LogHeapWordSize;
duke@435	161	size_t free_bytes = sp->free();
duke@435	162	while(buf_space == NULL && free_bytes >= min_bytes) {
duke@435	163	buf_size = free_bytes >> LogHeapWordSize;
duke@435	164	assert(buf_size == (size_t)align_object_size(buf_size),
duke@435	165	"Invariant");
duke@435	166	buf_space = sp->par_allocate(buf_size);
duke@435	167	free_bytes = sp->free();
duke@435	168	}
duke@435	169	}
duke@435	170	if (buf_space != NULL) {
duke@435	171	plab->set_word_size(buf_size);
duke@435	172	plab->set_buf(buf_space);
duke@435	173	record_survivor_plab(buf_space, buf_size);
duke@435	174	obj = plab->allocate(word_sz);
duke@435	175	// Note that we cannot compare buf_size < word_sz below
duke@435	176	// because of AlignmentReserve (see ParGCAllocBuffer::allocate()).
duke@435	177	assert(obj != NULL || plab->words_remaining() < word_sz,
duke@435	178	"Else should have been able to allocate");
duke@435	179	// It's conceivable that we may be able to use the
duke@435	180	// buffer we just grabbed for subsequent small requests
duke@435	181	// even if not for this one.
duke@435	182	} else {
duke@435	183	// We're used up.
duke@435	184	_to_space_full = true;
duke@435	185	}
duke@435	186
duke@435	187	} else {
duke@435	188	// Too large; allocate the object individually.
duke@435	189	obj = sp->par_allocate(word_sz);
duke@435	190	}
duke@435	191	}
duke@435	192	return obj;
duke@435	193	}
duke@435	194
duke@435	195
duke@435	196	void ParScanThreadState::undo_alloc_in_to_space(HeapWord* obj,
duke@435	197	size_t word_sz) {
duke@435	198	// Is the alloc in the current alloc buffer?
duke@435	199	if (to_space_alloc_buffer()->contains(obj)) {
duke@435	200	assert(to_space_alloc_buffer()->contains(obj + word_sz - 1),
duke@435	201	"Should contain whole object.");
duke@435	202	to_space_alloc_buffer()->undo_allocation(obj, word_sz);
duke@435	203	} else {
jcoomes@916	204	CollectedHeap::fill_with_object(obj, word_sz);
duke@435	205	}
duke@435	206	}
duke@435	207
duke@435	208	class ParScanThreadStateSet: private ResourceArray {
duke@435	209	public:
duke@435	210	// Initializes states for the specified number of threads;
duke@435	211	ParScanThreadStateSet(int num_threads,
duke@435	212	Space& to_space,
duke@435	213	ParNewGeneration& gen,
duke@435	214	Generation& old_gen,
duke@435	215	ObjToScanQueueSet& queue_set,
duke@435	216	size_t desired_plab_sz,
duke@435	217	ParallelTaskTerminator& term);
duke@435	218	inline ParScanThreadState& thread_sate(int i);
duke@435	219	int pushes() { return _pushes; }
duke@435	220	int pops() { return _pops; }
duke@435	221	int steals() { return _steals; }
duke@435	222	void reset();
duke@435	223	void flush();
duke@435	224	private:
duke@435	225	ParallelTaskTerminator& _term;
duke@435	226	ParNewGeneration& _gen;
duke@435	227	Generation& _next_gen;
duke@435	228	// staticstics
duke@435	229	int _pushes;
duke@435	230	int _pops;
duke@435	231	int _steals;
duke@435	232	};
duke@435	233
duke@435	234
duke@435	235	ParScanThreadStateSet::ParScanThreadStateSet(
duke@435	236	int num_threads, Space& to_space, ParNewGeneration& gen,
duke@435	237	Generation& old_gen, ObjToScanQueueSet& queue_set,
duke@435	238	size_t desired_plab_sz, ParallelTaskTerminator& term)
duke@435	239	: ResourceArray(sizeof(ParScanThreadState), num_threads),
duke@435	240	_gen(gen), _next_gen(old_gen), _term(term),
duke@435	241	_pushes(0), _pops(0), _steals(0)
duke@435	242	{
duke@435	243	assert(num_threads > 0, "sanity check!");
duke@435	244	// Initialize states.
duke@435	245	for (int i = 0; i < num_threads; ++i) {
duke@435	246	new ((ParScanThreadState*)_data + i)
duke@435	247	ParScanThreadState(&to_space, &gen, &old_gen, i, &queue_set,
duke@435	248	desired_plab_sz, term);
duke@435	249	}
duke@435	250	}
duke@435	251
duke@435	252	inline ParScanThreadState& ParScanThreadStateSet::thread_sate(int i)
duke@435	253	{
duke@435	254	assert(i >= 0 && i < length(), "sanity check!");
duke@435	255	return ((ParScanThreadState*)_data)[i];
duke@435	256	}
duke@435	257
duke@435	258
duke@435	259	void ParScanThreadStateSet::reset()
duke@435	260	{
duke@435	261	_term.reset_for_reuse();
duke@435	262	}
duke@435	263
duke@435	264	void ParScanThreadStateSet::flush()
duke@435	265	{
duke@435	266	for (int i = 0; i < length(); ++i) {
duke@435	267	ParScanThreadState& par_scan_state = thread_sate(i);
duke@435	268
duke@435	269	// Flush stats related to To-space PLAB activity and
duke@435	270	// retire the last buffer.
duke@435	271	par_scan_state.to_space_alloc_buffer()->
duke@435	272	flush_stats_and_retire(_gen.plab_stats(),
duke@435	273	false /* !retain */);
duke@435	274
duke@435	275	// Every thread has its own age table. We need to merge
duke@435	276	// them all into one.
duke@435	277	ageTable *local_table = par_scan_state.age_table();
duke@435	278	_gen.age_table()->merge(local_table);
duke@435	279
duke@435	280	// Inform old gen that we're done.
duke@435	281	_next_gen.par_promote_alloc_done(i);
duke@435	282	_next_gen.par_oop_since_save_marks_iterate_done(i);
duke@435	283
duke@435	284	// Flush stats related to work queue activity (push/pop/steal)
duke@435	285	// This could conceivably become a bottleneck; if so, we'll put the
duke@435	286	// stat's gathering under the flag.
duke@435	287	if (PAR_STATS_ENABLED) {
duke@435	288	_pushes += par_scan_state.pushes();
duke@435	289	_pops += par_scan_state.pops();
duke@435	290	_steals += par_scan_state.steals();
duke@435	291	if (ParallelGCVerbose) {
duke@435	292	gclog_or_tty->print("Thread %d complete:\n"
duke@435	293	" Pushes: %7d Pops: %7d Steals %7d (in %d attempts)\n",
duke@435	294	i, par_scan_state.pushes(), par_scan_state.pops(),
duke@435	295	par_scan_state.steals(), par_scan_state.steal_attempts());
duke@435	296	if (par_scan_state.overflow_pushes() > 0 ||
duke@435	297	par_scan_state.overflow_refills() > 0) {
duke@435	298	gclog_or_tty->print(" Overflow pushes: %7d "
duke@435	299	"Overflow refills: %7d for %d objs.\n",
duke@435	300	par_scan_state.overflow_pushes(),
duke@435	301	par_scan_state.overflow_refills(),
duke@435	302	par_scan_state.overflow_refill_objs());
duke@435	303	}
duke@435	304
duke@435	305	double elapsed = par_scan_state.elapsed();
duke@435	306	double strong_roots = par_scan_state.strong_roots_time();
duke@435	307	double term = par_scan_state.term_time();
duke@435	308	gclog_or_tty->print(
duke@435	309	" Elapsed: %7.2f ms.\n"
duke@435	310	" Strong roots: %7.2f ms (%6.2f%%)\n"
duke@435	311	" Termination: %7.2f ms (%6.2f%%) (in %d entries)\n",
duke@435	312	elapsed * 1000.0,
duke@435	313	strong_roots * 1000.0, (strong_roots*100.0/elapsed),
duke@435	314	term * 1000.0, (term*100.0/elapsed),
duke@435	315	par_scan_state.term_attempts());
duke@435	316	}
duke@435	317	}
duke@435	318	}
duke@435	319	}
duke@435	320
duke@435	321	ParScanClosure::ParScanClosure(ParNewGeneration* g,
duke@435	322	ParScanThreadState* par_scan_state) :
duke@435	323	OopsInGenClosure(g), _par_scan_state(par_scan_state), _g(g)
duke@435	324	{
duke@435	325	assert(_g->level() == 0, "Optimized for youngest generation");
duke@435	326	_boundary = _g->reserved().end();
duke@435	327	}
duke@435	328
coleenp@548	329	void ParScanWithBarrierClosure::do_oop(oop* p) { ParScanClosure::do_oop_work(p, true, false); }
coleenp@548	330	void ParScanWithBarrierClosure::do_oop(narrowOop* p) { ParScanClosure::do_oop_work(p, true, false); }
coleenp@548	331
coleenp@548	332	void ParScanWithoutBarrierClosure::do_oop(oop* p) { ParScanClosure::do_oop_work(p, false, false); }
coleenp@548	333	void ParScanWithoutBarrierClosure::do_oop(narrowOop* p) { ParScanClosure::do_oop_work(p, false, false); }
coleenp@548	334
coleenp@548	335	void ParRootScanWithBarrierTwoGensClosure::do_oop(oop* p) { ParScanClosure::do_oop_work(p, true, true); }
coleenp@548	336	void ParRootScanWithBarrierTwoGensClosure::do_oop(narrowOop* p) { ParScanClosure::do_oop_work(p, true, true); }
coleenp@548	337
coleenp@548	338	void ParRootScanWithoutBarrierClosure::do_oop(oop* p) { ParScanClosure::do_oop_work(p, false, true); }
coleenp@548	339	void ParRootScanWithoutBarrierClosure::do_oop(narrowOop* p) { ParScanClosure::do_oop_work(p, false, true); }
coleenp@548	340
duke@435	341	ParScanWeakRefClosure::ParScanWeakRefClosure(ParNewGeneration* g,
duke@435	342	ParScanThreadState* par_scan_state)
duke@435	343	: ScanWeakRefClosure(g), _par_scan_state(par_scan_state)
coleenp@548	344	{}
coleenp@548	345
coleenp@548	346	void ParScanWeakRefClosure::do_oop(oop* p) { ParScanWeakRefClosure::do_oop_work(p); }
coleenp@548	347	void ParScanWeakRefClosure::do_oop(narrowOop* p) { ParScanWeakRefClosure::do_oop_work(p); }
duke@435	348
duke@435	349	#ifdef WIN32
duke@435	350	#pragma warning(disable: 4786) /* identifier was truncated to '255' characters in the browser information */
duke@435	351	#endif
duke@435	352
duke@435	353	ParEvacuateFollowersClosure::ParEvacuateFollowersClosure(
duke@435	354	ParScanThreadState* par_scan_state_,
duke@435	355	ParScanWithoutBarrierClosure* to_space_closure_,
duke@435	356	ParScanWithBarrierClosure* old_gen_closure_,
duke@435	357	ParRootScanWithoutBarrierClosure* to_space_root_closure_,
duke@435	358	ParNewGeneration* par_gen_,
duke@435	359	ParRootScanWithBarrierTwoGensClosure* old_gen_root_closure_,
duke@435	360	ObjToScanQueueSet* task_queues_,
duke@435	361	ParallelTaskTerminator* terminator_) :
duke@435	362
duke@435	363	_par_scan_state(par_scan_state_),
duke@435	364	_to_space_closure(to_space_closure_),
duke@435	365	_old_gen_closure(old_gen_closure_),
duke@435	366	_to_space_root_closure(to_space_root_closure_),
duke@435	367	_old_gen_root_closure(old_gen_root_closure_),
duke@435	368	_par_gen(par_gen_),
duke@435	369	_task_queues(task_queues_),
duke@435	370	_terminator(terminator_)
duke@435	371	{}
duke@435	372
duke@435	373	void ParEvacuateFollowersClosure::do_void() {
duke@435	374	ObjToScanQueue* work_q = par_scan_state()->work_queue();
duke@435	375
duke@435	376	while (true) {
duke@435	377
duke@435	378	// Scan to-space and old-gen objs until we run out of both.
duke@435	379	oop obj_to_scan;
duke@435	380	par_scan_state()->trim_queues(0);
duke@435	381
duke@435	382	// We have no local work, attempt to steal from other threads.
duke@435	383
duke@435	384	// attempt to steal work from promoted.
duke@435	385	par_scan_state()->note_steal_attempt();
duke@435	386	if (task_queues()->steal(par_scan_state()->thread_num(),
duke@435	387	par_scan_state()->hash_seed(),
duke@435	388	obj_to_scan)) {
duke@435	389	par_scan_state()->note_steal();
duke@435	390	bool res = work_q->push(obj_to_scan);
duke@435	391	assert(res, "Empty queue should have room for a push.");
duke@435	392
duke@435	393	par_scan_state()->note_push();
duke@435	394	// if successful, goto Start.
duke@435	395	continue;
duke@435	396
duke@435	397	// try global overflow list.
duke@435	398	} else if (par_gen()->take_from_overflow_list(par_scan_state())) {
duke@435	399	continue;
duke@435	400	}
duke@435	401
duke@435	402	// Otherwise, offer termination.
duke@435	403	par_scan_state()->start_term_time();
duke@435	404	if (terminator()->offer_termination()) break;
duke@435	405	par_scan_state()->end_term_time();
duke@435	406	}
ysr@969	407	assert(par_gen()->_overflow_list == NULL && par_gen()->_num_par_pushes == 0,
ysr@969	408	"Broken overflow list?");
duke@435	409	// Finish the last termination pause.
duke@435	410	par_scan_state()->end_term_time();
duke@435	411	}
duke@435	412
duke@435	413	ParNewGenTask::ParNewGenTask(ParNewGeneration* gen, Generation* next_gen,
duke@435	414	HeapWord* young_old_boundary, ParScanThreadStateSet* state_set) :
duke@435	415	AbstractGangTask("ParNewGeneration collection"),
duke@435	416	_gen(gen), _next_gen(next_gen),
duke@435	417	_young_old_boundary(young_old_boundary),
duke@435	418	_state_set(state_set)
duke@435	419	{}
duke@435	420
duke@435	421	void ParNewGenTask::work(int i) {
duke@435	422	GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435	423	// Since this is being done in a separate thread, need new resource
duke@435	424	// and handle marks.
duke@435	425	ResourceMark rm;
duke@435	426	HandleMark hm;
duke@435	427	// We would need multiple old-gen queues otherwise.
duke@435	428	guarantee(gch->n_gens() == 2,
duke@435	429	"Par young collection currently only works with one older gen.");
duke@435	430
duke@435	431	Generation* old_gen = gch->next_gen(_gen);
duke@435	432
duke@435	433	ParScanThreadState& par_scan_state = _state_set->thread_sate(i);
duke@435	434	par_scan_state.set_young_old_boundary(_young_old_boundary);
duke@435	435
duke@435	436	par_scan_state.start_strong_roots();
duke@435	437	gch->gen_process_strong_roots(_gen->level(),
duke@435	438	true, // Process younger gens, if any,
duke@435	439	// as strong roots.
duke@435	440	false,// not collecting perm generation.
duke@435	441	SharedHeap::SO_AllClasses,
duke@435	442	&par_scan_state.older_gen_closure(),
duke@435	443	&par_scan_state.to_space_root_closure());
duke@435	444	par_scan_state.end_strong_roots();
duke@435	445
duke@435	446	// "evacuate followers".
duke@435	447	par_scan_state.evacuate_followers_closure().do_void();
duke@435	448	}
duke@435	449
duke@435	450	#ifdef _MSC_VER
duke@435	451	#pragma warning( push )
duke@435	452	#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
duke@435	453	#endif
duke@435	454	ParNewGeneration::
duke@435	455	ParNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level)
duke@435	456	: DefNewGeneration(rs, initial_byte_size, level, "PCopy"),
duke@435	457	_overflow_list(NULL),
duke@435	458	_is_alive_closure(this),
duke@435	459	_plab_stats(YoungPLABSize, PLABWeight)
duke@435	460	{
ysr@969	461	NOT_PRODUCT(_overflow_counter = ParGCWorkQueueOverflowInterval;)
ysr@969	462	NOT_PRODUCT(_num_par_pushes = 0;)
duke@435	463	_task_queues = new ObjToScanQueueSet(ParallelGCThreads);
duke@435	464	guarantee(_task_queues != NULL, "task_queues allocation failure.");
duke@435	465
duke@435	466	for (uint i1 = 0; i1 < ParallelGCThreads; i1++) {
duke@435	467	ObjToScanQueuePadded *q_padded = new ObjToScanQueuePadded();
duke@435	468	guarantee(q_padded != NULL, "work_queue Allocation failure.");
duke@435	469
duke@435	470	_task_queues->register_queue(i1, &q_padded->work_queue);
duke@435	471	}
duke@435	472
duke@435	473	for (uint i2 = 0; i2 < ParallelGCThreads; i2++)
duke@435	474	_task_queues->queue(i2)->initialize();
duke@435	475
duke@435	476	if (UsePerfData) {
duke@435	477	EXCEPTION_MARK;
duke@435	478	ResourceMark rm;
duke@435	479
duke@435	480	const char* cname =
duke@435	481	PerfDataManager::counter_name(_gen_counters->name_space(), "threads");
duke@435	482	PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None,
duke@435	483	ParallelGCThreads, CHECK);
duke@435	484	}
duke@435	485	}
duke@435	486	#ifdef _MSC_VER
duke@435	487	#pragma warning( pop )
duke@435	488	#endif
duke@435	489
duke@435	490	// ParNewGeneration::
duke@435	491	ParKeepAliveClosure::ParKeepAliveClosure(ParScanWeakRefClosure* cl) :
duke@435	492	DefNewGeneration::KeepAliveClosure(cl), _par_cl(cl) {}
duke@435	493
coleenp@548	494	template <class T>
coleenp@548	495	void /*ParNewGeneration::*/ParKeepAliveClosure::do_oop_work(T* p) {
coleenp@548	496	#ifdef ASSERT
coleenp@548	497	{
coleenp@548	498	assert(!oopDesc::is_null(*p), "expected non-null ref");
coleenp@548	499	oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548	500	// We never expect to see a null reference being processed
coleenp@548	501	// as a weak reference.
coleenp@548	502	assert(obj->is_oop(), "expected an oop while scanning weak refs");
coleenp@548	503	}
coleenp@548	504	#endif // ASSERT
duke@435	505
duke@435	506	_par_cl->do_oop_nv(p);
duke@435	507
duke@435	508	if (Universe::heap()->is_in_reserved(p)) {
coleenp@548	509	oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548	510	_rs->write_ref_field_gc_par(p, obj);
duke@435	511	}
duke@435	512	}
duke@435	513
coleenp@548	514	void /*ParNewGeneration::*/ParKeepAliveClosure::do_oop(oop* p) { ParKeepAliveClosure::do_oop_work(p); }
coleenp@548	515	void /*ParNewGeneration::*/ParKeepAliveClosure::do_oop(narrowOop* p) { ParKeepAliveClosure::do_oop_work(p); }
coleenp@548	516
duke@435	517	// ParNewGeneration::
duke@435	518	KeepAliveClosure::KeepAliveClosure(ScanWeakRefClosure* cl) :
duke@435	519	DefNewGeneration::KeepAliveClosure(cl) {}
duke@435	520
coleenp@548	521	template <class T>
coleenp@548	522	void /*ParNewGeneration::*/KeepAliveClosure::do_oop_work(T* p) {
coleenp@548	523	#ifdef ASSERT
coleenp@548	524	{
coleenp@548	525	assert(!oopDesc::is_null(*p), "expected non-null ref");
coleenp@548	526	oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548	527	// We never expect to see a null reference being processed
coleenp@548	528	// as a weak reference.
coleenp@548	529	assert(obj->is_oop(), "expected an oop while scanning weak refs");
coleenp@548	530	}
coleenp@548	531	#endif // ASSERT
duke@435	532
duke@435	533	_cl->do_oop_nv(p);
duke@435	534
duke@435	535	if (Universe::heap()->is_in_reserved(p)) {
coleenp@548	536	oop obj = oopDesc::load_decode_heap_oop_not_null(p);
coleenp@548	537	_rs->write_ref_field_gc_par(p, obj);
duke@435	538	}
duke@435	539	}
duke@435	540
coleenp@548	541	void /*ParNewGeneration::*/KeepAliveClosure::do_oop(oop* p) { KeepAliveClosure::do_oop_work(p); }
coleenp@548	542	void /*ParNewGeneration::*/KeepAliveClosure::do_oop(narrowOop* p) { KeepAliveClosure::do_oop_work(p); }
coleenp@548	543
coleenp@548	544	template <class T> void ScanClosureWithParBarrier::do_oop_work(T* p) {
coleenp@548	545	T heap_oop = oopDesc::load_heap_oop(p);
coleenp@548	546	if (!oopDesc::is_null(heap_oop)) {
coleenp@548	547	oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
duke@435	548	if ((HeapWord*)obj < _boundary) {
duke@435	549	assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");
coleenp@548	550	oop new_obj = obj->is_forwarded()
coleenp@548	551	? obj->forwardee()
coleenp@548	552	: _g->DefNewGeneration::copy_to_survivor_space(obj);
coleenp@548	553	oopDesc::encode_store_heap_oop_not_null(p, new_obj);
duke@435	554	}
duke@435	555	if (_gc_barrier) {
duke@435	556	// If p points to a younger generation, mark the card.
duke@435	557	if ((HeapWord*)obj < _gen_boundary) {
duke@435	558	_rs->write_ref_field_gc_par(p, obj);
duke@435	559	}
duke@435	560	}
duke@435	561	}
duke@435	562	}
duke@435	563
coleenp@548	564	void ScanClosureWithParBarrier::do_oop(oop* p) { ScanClosureWithParBarrier::do_oop_work(p); }
coleenp@548	565	void ScanClosureWithParBarrier::do_oop(narrowOop* p) { ScanClosureWithParBarrier::do_oop_work(p); }
coleenp@548	566
duke@435	567	class ParNewRefProcTaskProxy: public AbstractGangTask {
duke@435	568	typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
duke@435	569	public:
duke@435	570	ParNewRefProcTaskProxy(ProcessTask& task, ParNewGeneration& gen,
duke@435	571	Generation& next_gen,
duke@435	572	HeapWord* young_old_boundary,
duke@435	573	ParScanThreadStateSet& state_set);
duke@435	574
duke@435	575	private:
duke@435	576	virtual void work(int i);
duke@435	577
duke@435	578	private:
duke@435	579	ParNewGeneration& _gen;
duke@435	580	ProcessTask& _task;
duke@435	581	Generation& _next_gen;
duke@435	582	HeapWord* _young_old_boundary;
duke@435	583	ParScanThreadStateSet& _state_set;
duke@435	584	};
duke@435	585
duke@435	586	ParNewRefProcTaskProxy::ParNewRefProcTaskProxy(
duke@435	587	ProcessTask& task, ParNewGeneration& gen,
duke@435	588	Generation& next_gen,
duke@435	589	HeapWord* young_old_boundary,
duke@435	590	ParScanThreadStateSet& state_set)
duke@435	591	: AbstractGangTask("ParNewGeneration parallel reference processing"),
duke@435	592	_gen(gen),
duke@435	593	_task(task),
duke@435	594	_next_gen(next_gen),
duke@435	595	_young_old_boundary(young_old_boundary),
duke@435	596	_state_set(state_set)
duke@435	597	{
duke@435	598	}
duke@435	599
duke@435	600	void ParNewRefProcTaskProxy::work(int i)
duke@435	601	{
duke@435	602	ResourceMark rm;
duke@435	603	HandleMark hm;
duke@435	604	ParScanThreadState& par_scan_state = _state_set.thread_sate(i);
duke@435	605	par_scan_state.set_young_old_boundary(_young_old_boundary);
duke@435	606	_task.work(i, par_scan_state.is_alive_closure(),
duke@435	607	par_scan_state.keep_alive_closure(),
duke@435	608	par_scan_state.evacuate_followers_closure());
duke@435	609	}
duke@435	610
duke@435	611	class ParNewRefEnqueueTaskProxy: public AbstractGangTask {
duke@435	612	typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
duke@435	613	EnqueueTask& _task;
duke@435	614
duke@435	615	public:
duke@435	616	ParNewRefEnqueueTaskProxy(EnqueueTask& task)
duke@435	617	: AbstractGangTask("ParNewGeneration parallel reference enqueue"),
duke@435	618	_task(task)
duke@435	619	{ }
duke@435	620
duke@435	621	virtual void work(int i)
duke@435	622	{
duke@435	623	_task.work(i);
duke@435	624	}
duke@435	625	};
duke@435	626
duke@435	627
duke@435	628	void ParNewRefProcTaskExecutor::execute(ProcessTask& task)
duke@435	629	{
duke@435	630	GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435	631	assert(gch->kind() == CollectedHeap::GenCollectedHeap,
duke@435	632	"not a generational heap");
duke@435	633	WorkGang* workers = gch->workers();
duke@435	634	assert(workers != NULL, "Need parallel worker threads.");
duke@435	635	ParNewRefProcTaskProxy rp_task(task, _generation, *_generation.next_gen(),
duke@435	636	_generation.reserved().end(), _state_set);
duke@435	637	workers->run_task(&rp_task);
duke@435	638	_state_set.reset();
duke@435	639	}
duke@435	640
duke@435	641	void ParNewRefProcTaskExecutor::execute(EnqueueTask& task)
duke@435	642	{
duke@435	643	GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435	644	WorkGang* workers = gch->workers();
duke@435	645	assert(workers != NULL, "Need parallel worker threads.");
duke@435	646	ParNewRefEnqueueTaskProxy enq_task(task);
duke@435	647	workers->run_task(&enq_task);
duke@435	648	}
duke@435	649
duke@435	650	void ParNewRefProcTaskExecutor::set_single_threaded_mode()
duke@435	651	{
duke@435	652	_state_set.flush();
duke@435	653	GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435	654	gch->set_par_threads(0); // 0 ==> non-parallel.
duke@435	655	gch->save_marks();
duke@435	656	}
duke@435	657
duke@435	658	ScanClosureWithParBarrier::
duke@435	659	ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier) :
duke@435	660	ScanClosure(g, gc_barrier) {}
duke@435	661
duke@435	662	EvacuateFollowersClosureGeneral::
duke@435	663	EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, int level,
duke@435	664	OopsInGenClosure* cur,
duke@435	665	OopsInGenClosure* older) :
duke@435	666	_gch(gch), _level(level),
duke@435	667	_scan_cur_or_nonheap(cur), _scan_older(older)
duke@435	668	{}
duke@435	669
duke@435	670	void EvacuateFollowersClosureGeneral::do_void() {
duke@435	671	do {
duke@435	672	// Beware: this call will lead to closure applications via virtual
duke@435	673	// calls.
duke@435	674	_gch->oop_since_save_marks_iterate(_level,
duke@435	675	_scan_cur_or_nonheap,
duke@435	676	_scan_older);
duke@435	677	} while (!_gch->no_allocs_since_save_marks(_level));
duke@435	678	}
duke@435	679
duke@435	680
duke@435	681	bool ParNewGeneration::_avoid_promotion_undo = false;
duke@435	682
duke@435	683	void ParNewGeneration::adjust_desired_tenuring_threshold() {
duke@435	684	// Set the desired survivor size to half the real survivor space
duke@435	685	_tenuring_threshold =
duke@435	686	age_table()->compute_tenuring_threshold(to()->capacity()/HeapWordSize);
duke@435	687	}
duke@435	688
duke@435	689	// A Generation that does parallel young-gen collection.
duke@435	690
duke@435	691	void ParNewGeneration::collect(bool full,
duke@435	692	bool clear_all_soft_refs,
duke@435	693	size_t size,
duke@435	694	bool is_tlab) {
duke@435	695	assert(full || size > 0, "otherwise we don't want to collect");
duke@435	696	GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435	697	assert(gch->kind() == CollectedHeap::GenCollectedHeap,
duke@435	698	"not a CMS generational heap");
duke@435	699	AdaptiveSizePolicy* size_policy = gch->gen_policy()->size_policy();
duke@435	700	WorkGang* workers = gch->workers();
duke@435	701	_next_gen = gch->next_gen(this);
duke@435	702	assert(_next_gen != NULL,
duke@435	703	"This must be the youngest gen, and not the only gen");
duke@435	704	assert(gch->n_gens() == 2,
duke@435	705	"Par collection currently only works with single older gen.");
duke@435	706	// Do we have to avoid promotion_undo?
duke@435	707	if (gch->collector_policy()->is_concurrent_mark_sweep_policy()) {
duke@435	708	set_avoid_promotion_undo(true);
duke@435	709	}
duke@435	710
duke@435	711	// If the next generation is too full to accomodate worst-case promotion
duke@435	712	// from this generation, pass on collection; let the next generation
duke@435	713	// do it.
duke@435	714	if (!collection_attempt_is_safe()) {
duke@435	715	gch->set_incremental_collection_will_fail();
duke@435	716	return;
duke@435	717	}
duke@435	718	assert(to()->is_empty(), "Else not collection_attempt_is_safe");
duke@435	719
duke@435	720	init_assuming_no_promotion_failure();
duke@435	721
duke@435	722	if (UseAdaptiveSizePolicy) {
duke@435	723	set_survivor_overflow(false);
duke@435	724	size_policy->minor_collection_begin();
duke@435	725	}
duke@435	726
duke@435	727	TraceTime t1("GC", PrintGC && !PrintGCDetails, true, gclog_or_tty);
duke@435	728	// Capture heap used before collection (for printing).
duke@435	729	size_t gch_prev_used = gch->used();
duke@435	730
duke@435	731	SpecializationStats::clear();
duke@435	732
duke@435	733	age_table()->clear();
jmasa@698	734	to()->clear(SpaceDecorator::Mangle);
duke@435	735
duke@435	736	gch->save_marks();
duke@435	737	assert(workers != NULL, "Need parallel worker threads.");
duke@435	738	ParallelTaskTerminator _term(workers->total_workers(), task_queues());
duke@435	739	ParScanThreadStateSet thread_state_set(workers->total_workers(),
duke@435	740	*to(), *this, *_next_gen, *task_queues(),
duke@435	741	desired_plab_sz(), _term);
duke@435	742
duke@435	743	ParNewGenTask tsk(this, _next_gen, reserved().end(), &thread_state_set);
duke@435	744	int n_workers = workers->total_workers();
duke@435	745	gch->set_par_threads(n_workers);
duke@435	746	gch->change_strong_roots_parity();
duke@435	747	gch->rem_set()->prepare_for_younger_refs_iterate(true);
duke@435	748	// It turns out that even when we're using 1 thread, doing the work in a
duke@435	749	// separate thread causes wide variance in run times. We can't help this
duke@435	750	// in the multi-threaded case, but we special-case n=1 here to get
duke@435	751	// repeatable measurements of the 1-thread overhead of the parallel code.
duke@435	752	if (n_workers > 1) {
duke@435	753	workers->run_task(&tsk);
duke@435	754	} else {
duke@435	755	tsk.work(0);
duke@435	756	}
duke@435	757	thread_state_set.reset();
duke@435	758
duke@435	759	if (PAR_STATS_ENABLED && ParallelGCVerbose) {
duke@435	760	gclog_or_tty->print("Thread totals:\n"
duke@435	761	" Pushes: %7d Pops: %7d Steals %7d (sum = %7d).\n",
duke@435	762	thread_state_set.pushes(), thread_state_set.pops(),
duke@435	763	thread_state_set.steals(),
duke@435	764	thread_state_set.pops()+thread_state_set.steals());
duke@435	765	}
ysr@888	766	assert(thread_state_set.pushes() == thread_state_set.pops()
ysr@888	767	+ thread_state_set.steals(),
duke@435	768	"Or else the queues are leaky.");
duke@435	769
duke@435	770	// Process (weak) reference objects found during scavenge.
ysr@888	771	ReferenceProcessor* rp = ref_processor();
duke@435	772	IsAliveClosure is_alive(this);
duke@435	773	ScanWeakRefClosure scan_weak_ref(this);
duke@435	774	KeepAliveClosure keep_alive(&scan_weak_ref);
duke@435	775	ScanClosure scan_without_gc_barrier(this, false);
duke@435	776	ScanClosureWithParBarrier scan_with_gc_barrier(this, true);
duke@435	777	set_promo_failure_scan_stack_closure(&scan_without_gc_barrier);
duke@435	778	EvacuateFollowersClosureGeneral evacuate_followers(gch, _level,
duke@435	779	&scan_without_gc_barrier, &scan_with_gc_barrier);
ysr@892	780	rp->setup_policy(clear_all_soft_refs);
ysr@888	781	if (rp->processing_is_mt()) {
duke@435	782	ParNewRefProcTaskExecutor task_executor(*this, thread_state_set);
ysr@888	783	rp->process_discovered_references(&is_alive, &keep_alive,
ysr@888	784	&evacuate_followers, &task_executor);
duke@435	785	} else {
duke@435	786	thread_state_set.flush();
duke@435	787	gch->set_par_threads(0); // 0 ==> non-parallel.
duke@435	788	gch->save_marks();
ysr@888	789	rp->process_discovered_references(&is_alive, &keep_alive,
ysr@888	790	&evacuate_followers, NULL);
duke@435	791	}
duke@435	792	if (!promotion_failed()) {
duke@435	793	// Swap the survivor spaces.
jmasa@698	794	eden()->clear(SpaceDecorator::Mangle);
jmasa@698	795	from()->clear(SpaceDecorator::Mangle);
jmasa@698	796	if (ZapUnusedHeapArea) {
jmasa@698	797	// This is now done here because of the piece-meal mangling which
jmasa@698	798	// can check for valid mangling at intermediate points in the
jmasa@698	799	// collection(s). When a minor collection fails to collect
jmasa@698	800	// sufficient space resizing of the young generation can occur
jmasa@698	801	// an redistribute the spaces in the young generation. Mangle
jmasa@698	802	// here so that unzapped regions don't get distributed to
jmasa@698	803	// other spaces.
jmasa@698	804	to()->mangle_unused_area();
jmasa@698	805	}
duke@435	806	swap_spaces();
duke@435	807
duke@435	808	assert(to()->is_empty(), "to space should be empty now");
duke@435	809	} else {
duke@435	810	assert(HandlePromotionFailure,
duke@435	811	"Should only be here if promotion failure handling is on");
duke@435	812	if (_promo_failure_scan_stack != NULL) {
duke@435	813	// Can be non-null because of reference processing.
duke@435	814	// Free stack with its elements.
duke@435	815	delete _promo_failure_scan_stack;
duke@435	816	_promo_failure_scan_stack = NULL;
duke@435	817	}
duke@435	818	remove_forwarding_pointers();
duke@435	819	if (PrintGCDetails) {
duke@435	820	gclog_or_tty->print(" (promotion failed)");
duke@435	821	}
duke@435	822	// All the spaces are in play for mark-sweep.
duke@435	823	swap_spaces(); // Make life simpler for CMS || rescan; see 6483690.
duke@435	824	from()->set_next_compaction_space(to());
duke@435	825	gch->set_incremental_collection_will_fail();
jmasa@441	826
jmasa@441	827	// Reset the PromotionFailureALot counters.
jmasa@441	828	NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();)
duke@435	829	}
duke@435	830	// set new iteration safe limit for the survivor spaces
duke@435	831	from()->set_concurrent_iteration_safe_limit(from()->top());
duke@435	832	to()->set_concurrent_iteration_safe_limit(to()->top());
duke@435	833
duke@435	834	adjust_desired_tenuring_threshold();
duke@435	835	if (ResizePLAB) {
duke@435	836	plab_stats()->adjust_desired_plab_sz();
duke@435	837	}
duke@435	838
duke@435	839	if (PrintGC && !PrintGCDetails) {
duke@435	840	gch->print_heap_change(gch_prev_used);
duke@435	841	}
duke@435	842
duke@435	843	if (UseAdaptiveSizePolicy) {
duke@435	844	size_policy->minor_collection_end(gch->gc_cause());
duke@435	845	size_policy->avg_survived()->sample(from()->used());
duke@435	846	}
duke@435	847
duke@435	848	update_time_of_last_gc(os::javaTimeMillis());
duke@435	849
duke@435	850	SpecializationStats::print();
duke@435	851
ysr@888	852	rp->set_enqueuing_is_done(true);
ysr@888	853	if (rp->processing_is_mt()) {
duke@435	854	ParNewRefProcTaskExecutor task_executor(*this, thread_state_set);
ysr@888	855	rp->enqueue_discovered_references(&task_executor);
duke@435	856	} else {
ysr@888	857	rp->enqueue_discovered_references(NULL);
duke@435	858	}
ysr@888	859	rp->verify_no_references_recorded();
duke@435	860	}
duke@435	861
duke@435	862	static int sum;
duke@435	863	void ParNewGeneration::waste_some_time() {
duke@435	864	for (int i = 0; i < 100; i++) {
duke@435	865	sum += i;
duke@435	866	}
duke@435	867	}
duke@435	868
duke@435	869	static const oop ClaimedForwardPtr = oop(0x4);
duke@435	870
duke@435	871	// Because of concurrency, there are times where an object for which
duke@435	872	// "is_forwarded()" is true contains an "interim" forwarding pointer
duke@435	873	// value. Such a value will soon be overwritten with a real value.
duke@435	874	// This method requires "obj" to have a forwarding pointer, and waits, if
duke@435	875	// necessary for a real one to be inserted, and returns it.
duke@435	876
duke@435	877	oop ParNewGeneration::real_forwardee(oop obj) {
duke@435	878	oop forward_ptr = obj->forwardee();
duke@435	879	if (forward_ptr != ClaimedForwardPtr) {
duke@435	880	return forward_ptr;
duke@435	881	} else {
duke@435	882	return real_forwardee_slow(obj);
duke@435	883	}
duke@435	884	}
duke@435	885
duke@435	886	oop ParNewGeneration::real_forwardee_slow(oop obj) {
duke@435	887	// Spin-read if it is claimed but not yet written by another thread.
duke@435	888	oop forward_ptr = obj->forwardee();
duke@435	889	while (forward_ptr == ClaimedForwardPtr) {
duke@435	890	waste_some_time();
duke@435	891	assert(obj->is_forwarded(), "precondition");
duke@435	892	forward_ptr = obj->forwardee();
duke@435	893	}
duke@435	894	return forward_ptr;
duke@435	895	}
duke@435	896
duke@435	897	#ifdef ASSERT
duke@435	898	bool ParNewGeneration::is_legal_forward_ptr(oop p) {
duke@435	899	return
duke@435	900	(_avoid_promotion_undo && p == ClaimedForwardPtr)
duke@435	901	|| Universe::heap()->is_in_reserved(p);
duke@435	902	}
duke@435	903	#endif
duke@435	904
duke@435	905	void ParNewGeneration::preserve_mark_if_necessary(oop obj, markOop m) {
duke@435	906	if ((m != markOopDesc::prototype()) &&
duke@435	907	(!UseBiasedLocking || (m != markOopDesc::biased_locking_prototype()))) {
duke@435	908	MutexLocker ml(ParGCRareEvent_lock);
duke@435	909	DefNewGeneration::preserve_mark_if_necessary(obj, m);
duke@435	910	}
duke@435	911	}
duke@435	912
duke@435	913	// Multiple GC threads may try to promote an object. If the object
duke@435	914	// is successfully promoted, a forwarding pointer will be installed in
duke@435	915	// the object in the young generation. This method claims the right
duke@435	916	// to install the forwarding pointer before it copies the object,
duke@435	917	// thus avoiding the need to undo the copy as in
duke@435	918	// copy_to_survivor_space_avoiding_with_undo.
duke@435	919
duke@435	920	oop ParNewGeneration::copy_to_survivor_space_avoiding_promotion_undo(
duke@435	921	ParScanThreadState* par_scan_state, oop old, size_t sz, markOop m) {
duke@435	922	// In the sequential version, this assert also says that the object is
duke@435	923	// not forwarded. That might not be the case here. It is the case that
duke@435	924	// the caller observed it to be not forwarded at some time in the past.
duke@435	925	assert(is_in_reserved(old), "shouldn't be scavenging this oop");
duke@435	926
duke@435	927	// The sequential code read "old->age()" below. That doesn't work here,
duke@435	928	// since the age is in the mark word, and that might be overwritten with
duke@435	929	// a forwarding pointer by a parallel thread. So we must save the mark
duke@435	930	// word in a local and then analyze it.
duke@435	931	oopDesc dummyOld;
duke@435	932	dummyOld.set_mark(m);
duke@435	933	assert(!dummyOld.is_forwarded(),
duke@435	934	"should not be called with forwarding pointer mark word.");
duke@435	935
duke@435	936	oop new_obj = NULL;
duke@435	937	oop forward_ptr;
duke@435	938
duke@435	939	// Try allocating obj in to-space (unless too old)
duke@435	940	if (dummyOld.age() < tenuring_threshold()) {
duke@435	941	new_obj = (oop)par_scan_state->alloc_in_to_space(sz);
duke@435	942	if (new_obj == NULL) {
duke@435	943	set_survivor_overflow(true);
duke@435	944	}
duke@435	945	}
duke@435	946
duke@435	947	if (new_obj == NULL) {
duke@435	948	// Either to-space is full or we decided to promote
duke@435	949	// try allocating obj tenured
duke@435	950
duke@435	951	// Attempt to install a null forwarding pointer (atomically),
duke@435	952	// to claim the right to install the real forwarding pointer.
duke@435	953	forward_ptr = old->forward_to_atomic(ClaimedForwardPtr);
duke@435	954	if (forward_ptr != NULL) {
duke@435	955	// someone else beat us to it.
duke@435	956	return real_forwardee(old);
duke@435	957	}
duke@435	958
duke@435	959	new_obj = _next_gen->par_promote(par_scan_state->thread_num(),
duke@435	960	old, m, sz);
duke@435	961
duke@435	962	if (new_obj == NULL) {
duke@435	963	if (!HandlePromotionFailure) {
duke@435	964	// A failed promotion likely means the MaxLiveObjectEvacuationRatio flag
duke@435	965	// is incorrectly set. In any case, its seriously wrong to be here!
duke@435	966	vm_exit_out_of_memory(sz*wordSize, "promotion");
duke@435	967	}
duke@435	968	// promotion failed, forward to self
duke@435	969	_promotion_failed = true;
duke@435	970	new_obj = old;
duke@435	971
duke@435	972	preserve_mark_if_necessary(old, m);
duke@435	973	}
duke@435	974
duke@435	975	old->forward_to(new_obj);
duke@435	976	forward_ptr = NULL;
duke@435	977	} else {
duke@435	978	// Is in to-space; do copying ourselves.
duke@435	979	Copy::aligned_disjoint_words((HeapWord*)old, (HeapWord*)new_obj, sz);
duke@435	980	forward_ptr = old->forward_to_atomic(new_obj);
duke@435	981	// Restore the mark word copied above.
duke@435	982	new_obj->set_mark(m);
duke@435	983	// Increment age if obj still in new generation
duke@435	984	new_obj->incr_age();
duke@435	985	par_scan_state->age_table()->add(new_obj, sz);
duke@435	986	}
duke@435	987	assert(new_obj != NULL, "just checking");
duke@435	988
duke@435	989	if (forward_ptr == NULL) {
duke@435	990	oop obj_to_push = new_obj;
duke@435	991	if (par_scan_state->should_be_partially_scanned(obj_to_push, old)) {
duke@435	992	// Length field used as index of next element to be scanned.
duke@435	993	// Real length can be obtained from real_forwardee()
duke@435	994	arrayOop(old)->set_length(0);
duke@435	995	obj_to_push = old;
duke@435	996	assert(obj_to_push->is_forwarded() && obj_to_push->forwardee() != obj_to_push,
duke@435	997	"push forwarded object");
duke@435	998	}
duke@435	999	// Push it on one of the queues of to-be-scanned objects.
ysr@969	1000	bool simulate_overflow = false;
ysr@969	1001	NOT_PRODUCT(
ysr@969	1002	if (ParGCWorkQueueOverflowALot && should_simulate_overflow()) {
ysr@969	1003	// simulate a stack overflow
ysr@969	1004	simulate_overflow = true;
ysr@969	1005	}
ysr@969	1006	)
ysr@969	1007	if (simulate_overflow || !par_scan_state->work_queue()->push(obj_to_push)) {
duke@435	1008	// Add stats for overflow pushes.
duke@435	1009	if (Verbose && PrintGCDetails) {
duke@435	1010	gclog_or_tty->print("queue overflow!\n");
duke@435	1011	}
ysr@969	1012	push_on_overflow_list(old, par_scan_state);
duke@435	1013	par_scan_state->note_overflow_push();
duke@435	1014	}
duke@435	1015	par_scan_state->note_push();
duke@435	1016
duke@435	1017	return new_obj;
duke@435	1018	}
duke@435	1019
duke@435	1020	// Oops. Someone beat us to it. Undo the allocation. Where did we
duke@435	1021	// allocate it?
duke@435	1022	if (is_in_reserved(new_obj)) {
duke@435	1023	// Must be in to_space.
duke@435	1024	assert(to()->is_in_reserved(new_obj), "Checking");
duke@435	1025	if (forward_ptr == ClaimedForwardPtr) {
duke@435	1026	// Wait to get the real forwarding pointer value.
duke@435	1027	forward_ptr = real_forwardee(old);
duke@435	1028	}
duke@435	1029	par_scan_state->undo_alloc_in_to_space((HeapWord*)new_obj, sz);
duke@435	1030	}
duke@435	1031
duke@435	1032	return forward_ptr;
duke@435	1033	}
duke@435	1034
duke@435	1035
duke@435	1036	// Multiple GC threads may try to promote the same object. If two
duke@435	1037	// or more GC threads copy the object, only one wins the race to install
duke@435	1038	// the forwarding pointer. The other threads have to undo their copy.
duke@435	1039
duke@435	1040	oop ParNewGeneration::copy_to_survivor_space_with_undo(
duke@435	1041	ParScanThreadState* par_scan_state, oop old, size_t sz, markOop m) {
duke@435	1042
duke@435	1043	// In the sequential version, this assert also says that the object is
duke@435	1044	// not forwarded. That might not be the case here. It is the case that
duke@435	1045	// the caller observed it to be not forwarded at some time in the past.
duke@435	1046	assert(is_in_reserved(old), "shouldn't be scavenging this oop");
duke@435	1047
duke@435	1048	// The sequential code read "old->age()" below. That doesn't work here,
duke@435	1049	// since the age is in the mark word, and that might be overwritten with
duke@435	1050	// a forwarding pointer by a parallel thread. So we must save the mark
duke@435	1051	// word here, install it in a local oopDesc, and then analyze it.
duke@435	1052	oopDesc dummyOld;
duke@435	1053	dummyOld.set_mark(m);
duke@435	1054	assert(!dummyOld.is_forwarded(),
duke@435	1055	"should not be called with forwarding pointer mark word.");
duke@435	1056
duke@435	1057	bool failed_to_promote = false;
duke@435	1058	oop new_obj = NULL;
duke@435	1059	oop forward_ptr;
duke@435	1060
duke@435	1061	// Try allocating obj in to-space (unless too old)
duke@435	1062	if (dummyOld.age() < tenuring_threshold()) {
duke@435	1063	new_obj = (oop)par_scan_state->alloc_in_to_space(sz);
duke@435	1064	if (new_obj == NULL) {
duke@435	1065	set_survivor_overflow(true);
duke@435	1066	}
duke@435	1067	}
duke@435	1068
duke@435	1069	if (new_obj == NULL) {
duke@435	1070	// Either to-space is full or we decided to promote
duke@435	1071	// try allocating obj tenured
duke@435	1072	new_obj = _next_gen->par_promote(par_scan_state->thread_num(),
duke@435	1073	old, m, sz);
duke@435	1074
duke@435	1075	if (new_obj == NULL) {
duke@435	1076	if (!HandlePromotionFailure) {
duke@435	1077	// A failed promotion likely means the MaxLiveObjectEvacuationRatio
duke@435	1078	// flag is incorrectly set. In any case, its seriously wrong to be
duke@435	1079	// here!
duke@435	1080	vm_exit_out_of_memory(sz*wordSize, "promotion");
duke@435	1081	}
duke@435	1082	// promotion failed, forward to self
duke@435	1083	forward_ptr = old->forward_to_atomic(old);
duke@435	1084	new_obj = old;
duke@435	1085
duke@435	1086	if (forward_ptr != NULL) {
duke@435	1087	return forward_ptr; // someone else succeeded
duke@435	1088	}
duke@435	1089
duke@435	1090	_promotion_failed = true;
duke@435	1091	failed_to_promote = true;
duke@435	1092
duke@435	1093	preserve_mark_if_necessary(old, m);
duke@435	1094	}
duke@435	1095	} else {
duke@435	1096	// Is in to-space; do copying ourselves.
duke@435	1097	Copy::aligned_disjoint_words((HeapWord*)old, (HeapWord*)new_obj, sz);
duke@435	1098	// Restore the mark word copied above.
duke@435	1099	new_obj->set_mark(m);
duke@435	1100	// Increment age if new_obj still in new generation
duke@435	1101	new_obj->incr_age();
duke@435	1102	par_scan_state->age_table()->add(new_obj, sz);
duke@435	1103	}
duke@435	1104	assert(new_obj != NULL, "just checking");
duke@435	1105
duke@435	1106	// Now attempt to install the forwarding pointer (atomically).
duke@435	1107	// We have to copy the mark word before overwriting with forwarding
duke@435	1108	// ptr, so we can restore it below in the copy.
duke@435	1109	if (!failed_to_promote) {
duke@435	1110	forward_ptr = old->forward_to_atomic(new_obj);
duke@435	1111	}
duke@435	1112
duke@435	1113	if (forward_ptr == NULL) {
duke@435	1114	oop obj_to_push = new_obj;
duke@435	1115	if (par_scan_state->should_be_partially_scanned(obj_to_push, old)) {
duke@435	1116	// Length field used as index of next element to be scanned.
duke@435	1117	// Real length can be obtained from real_forwardee()
duke@435	1118	arrayOop(old)->set_length(0);
duke@435	1119	obj_to_push = old;
duke@435	1120	assert(obj_to_push->is_forwarded() && obj_to_push->forwardee() != obj_to_push,
duke@435	1121	"push forwarded object");
duke@435	1122	}
duke@435	1123	// Push it on one of the queues of to-be-scanned objects.
ysr@969	1124	bool simulate_overflow = false;
ysr@969	1125	NOT_PRODUCT(
ysr@969	1126	if (ParGCWorkQueueOverflowALot && should_simulate_overflow()) {
ysr@969	1127	// simulate a stack overflow
ysr@969	1128	simulate_overflow = true;
ysr@969	1129	}
ysr@969	1130	)
ysr@969	1131	if (simulate_overflow || !par_scan_state->work_queue()->push(obj_to_push)) {
duke@435	1132	// Add stats for overflow pushes.
ysr@969	1133	push_on_overflow_list(old, par_scan_state);
duke@435	1134	par_scan_state->note_overflow_push();
duke@435	1135	}
duke@435	1136	par_scan_state->note_push();
duke@435	1137
duke@435	1138	return new_obj;
duke@435	1139	}
duke@435	1140
duke@435	1141	// Oops. Someone beat us to it. Undo the allocation. Where did we
duke@435	1142	// allocate it?
duke@435	1143	if (is_in_reserved(new_obj)) {
duke@435	1144	// Must be in to_space.
duke@435	1145	assert(to()->is_in_reserved(new_obj), "Checking");
duke@435	1146	par_scan_state->undo_alloc_in_to_space((HeapWord*)new_obj, sz);
duke@435	1147	} else {
duke@435	1148	assert(!_avoid_promotion_undo, "Should not be here if avoiding.");
duke@435	1149	_next_gen->par_promote_alloc_undo(par_scan_state->thread_num(),
duke@435	1150	(HeapWord*)new_obj, sz);
duke@435	1151	}
duke@435	1152
duke@435	1153	return forward_ptr;
duke@435	1154	}
duke@435	1155
ysr@969	1156	#ifndef PRODUCT
ysr@969	1157	// It's OK to call this multi-threaded; the worst thing
ysr@969	1158	// that can happen is that we'll get a bunch of closely
ysr@969	1159	// spaced simulated oveflows, but that's OK, in fact
ysr@969	1160	// probably good as it would exercise the overflow code
ysr@969	1161	// under contention.
ysr@969	1162	bool ParNewGeneration::should_simulate_overflow() {
ysr@969	1163	if (_overflow_counter-- <= 0) { // just being defensive
ysr@969	1164	_overflow_counter = ParGCWorkQueueOverflowInterval;
ysr@969	1165	return true;
ysr@969	1166	} else {
ysr@969	1167	return false;
ysr@969	1168	}
ysr@969	1169	}
ysr@969	1170	#endif
ysr@969	1171
ysr@969	1172	#define BUSY (oop(0x1aff1aff))
ysr@969	1173	void ParNewGeneration::push_on_overflow_list(oop from_space_obj, ParScanThreadState* par_scan_state) {
duke@435	1174	// if the object has been forwarded to itself, then we cannot
duke@435	1175	// use the klass pointer for the linked list. Instead we have
duke@435	1176	// to allocate an oopDesc in the C-Heap and use that for the linked list.
ysr@969	1177	// XXX This is horribly inefficient when a promotion failure occurs
ysr@969	1178	// and should be fixed. XXX FIX ME !!!
ysr@969	1179	#ifndef PRODUCT
ysr@969	1180	Atomic::inc_ptr(&_num_par_pushes);
ysr@969	1181	assert(_num_par_pushes > 0, "Tautology");
ysr@969	1182	#endif
duke@435	1183	if (from_space_obj->forwardee() == from_space_obj) {
duke@435	1184	oopDesc* listhead = NEW_C_HEAP_ARRAY(oopDesc, 1);
duke@435	1185	listhead->forward_to(from_space_obj);
duke@435	1186	from_space_obj = listhead;
duke@435	1187	}
ysr@969	1188	oop observed_overflow_list = _overflow_list;
ysr@969	1189	oop cur_overflow_list;
ysr@969	1190	do {
ysr@969	1191	cur_overflow_list = observed_overflow_list;
ysr@969	1192	if (cur_overflow_list != BUSY) {
ysr@969	1193	from_space_obj->set_klass_to_list_ptr(cur_overflow_list);
ysr@969	1194	} else {
ysr@969	1195	from_space_obj->set_klass_to_list_ptr(NULL);
ysr@969	1196	}
ysr@969	1197	observed_overflow_list =
duke@435	1198	(oop)Atomic::cmpxchg_ptr(from_space_obj, &_overflow_list, cur_overflow_list);
ysr@969	1199	} while (cur_overflow_list != observed_overflow_list);
duke@435	1200	}
duke@435	1201
ysr@969	1202	// *NOTE*: The overflow list manipulation code here and
ysr@969	1203	// in CMSCollector:: are very similar in shape,
ysr@969	1204	// except that in the CMS case we thread the objects
ysr@969	1205	// directly into the list via their mark word, and do
ysr@969	1206	// not need to deal with special cases below related
ysr@969	1207	// to chunking of object arrays and promotion failure
ysr@969	1208	// handling.
ysr@969	1209	// CR 6797058 has been filed to attempt consolidation of
ysr@969	1210	// the common code.
ysr@969	1211	// Because of the common code, if you make any changes in
ysr@969	1212	// the code below, please check the CMS version to see if
ysr@969	1213	// similar changes might be needed.
ysr@969	1214	// See CMSCollector::par_take_from_overflow_list() for
ysr@969	1215	// more extensive documentation comments.
duke@435	1216	bool
duke@435	1217	ParNewGeneration::take_from_overflow_list(ParScanThreadState* par_scan_state) {
duke@435	1218	ObjToScanQueue* work_q = par_scan_state->work_queue();
ysr@969	1219	assert(work_q->size() == 0, "Should first empty local work queue");
duke@435	1220	// How many to take?
ysr@969	1221	size_t objsFromOverflow = MIN2((size_t)work_q->max_elems()/4,
ysr@969	1222	(size_t)ParGCDesiredObjsFromOverflowList);
duke@435	1223
duke@435	1224	if (_overflow_list == NULL) return false;
duke@435	1225
duke@435	1226	// Otherwise, there was something there; try claiming the list.
ysr@969	1227	oop prefix = (oop)Atomic::xchg_ptr(BUSY, &_overflow_list);
ysr@969	1228	// Trim off a prefix of at most objsFromOverflow items
ysr@969	1229	Thread* tid = Thread::current();
ysr@969	1230	size_t spin_count = (size_t)ParallelGCThreads;
ysr@969	1231	size_t sleep_time_millis = MAX2((size_t)1, objsFromOverflow/100);
ysr@969	1232	for (size_t spin = 0; prefix == BUSY && spin < spin_count; spin++) {
ysr@969	1233	// someone grabbed it before we did ...
ysr@969	1234	// ... we spin for a short while...
ysr@969	1235	os::sleep(tid, sleep_time_millis, false);
ysr@969	1236	if (_overflow_list == NULL) {
ysr@969	1237	// nothing left to take
ysr@969	1238	return false;
ysr@969	1239	} else if (_overflow_list != BUSY) {
ysr@969	1240	// try and grab the prefix
ysr@969	1241	prefix = (oop)Atomic::xchg_ptr(BUSY, &_overflow_list);
ysr@969	1242	}
duke@435	1243	}
ysr@969	1244	if (prefix == NULL || prefix == BUSY) {
ysr@969	1245	// Nothing to take or waited long enough
ysr@969	1246	if (prefix == NULL) {
ysr@969	1247	// Write back the NULL in case we overwrote it with BUSY above
ysr@969	1248	// and it is still the same value.
ysr@969	1249	(void) Atomic::cmpxchg_ptr(NULL, &_overflow_list, BUSY);
ysr@969	1250	}
ysr@969	1251	return false;
ysr@969	1252	}
ysr@969	1253	assert(prefix != NULL && prefix != BUSY, "Error");
ysr@969	1254	size_t i = 1;
duke@435	1255	oop cur = prefix;
coleenp@602	1256	while (i < objsFromOverflow && cur->klass_or_null() != NULL) {
duke@435	1257	i++; cur = oop(cur->klass());
duke@435	1258	}
duke@435	1259
duke@435	1260	// Reattach remaining (suffix) to overflow list
ysr@969	1261	if (cur->klass_or_null() == NULL) {
ysr@969	1262	// Write back the NULL in lieu of the BUSY we wrote
ysr@969	1263	// above and it is still the same value.
ysr@969	1264	if (_overflow_list == BUSY) {
ysr@969	1265	(void) Atomic::cmpxchg_ptr(NULL, &_overflow_list, BUSY);
duke@435	1266	}
ysr@969	1267	} else {
ysr@969	1268	assert(cur->klass_or_null() != BUSY, "Error");
ysr@969	1269	oop suffix = oop(cur->klass()); // suffix will be put back on global list
ysr@969	1270	cur->set_klass_to_list_ptr(NULL); // break off suffix
ysr@969	1271	// It's possible that the list is still in the empty(busy) state
ysr@969	1272	// we left it in a short while ago; in that case we may be
ysr@969	1273	// able to place back the suffix.
ysr@969	1274	oop observed_overflow_list = _overflow_list;
ysr@969	1275	oop cur_overflow_list = observed_overflow_list;
ysr@969	1276	bool attached = false;
ysr@969	1277	while (observed_overflow_list == BUSY || observed_overflow_list == NULL) {
ysr@969	1278	observed_overflow_list =
ysr@969	1279	(oop) Atomic::cmpxchg_ptr(suffix, &_overflow_list, cur_overflow_list);
ysr@969	1280	if (cur_overflow_list == observed_overflow_list) {
ysr@969	1281	attached = true;
ysr@969	1282	break;
ysr@969	1283	} else cur_overflow_list = observed_overflow_list;
ysr@969	1284	}
ysr@969	1285	if (!attached) {
ysr@969	1286	// Too bad, someone else got in in between; we'll need to do a splice.
ysr@969	1287	// Find the last item of suffix list
ysr@969	1288	oop last = suffix;
ysr@969	1289	while (last->klass_or_null() != NULL) {
ysr@969	1290	last = oop(last->klass());
ysr@969	1291	}
ysr@969	1292	// Atomically prepend suffix to current overflow list
ysr@969	1293	observed_overflow_list = _overflow_list;
ysr@969	1294	do {
ysr@969	1295	cur_overflow_list = observed_overflow_list;
ysr@969	1296	if (cur_overflow_list != BUSY) {
ysr@969	1297	// Do the splice ...
ysr@969	1298	last->set_klass_to_list_ptr(cur_overflow_list);
ysr@969	1299	} else { // cur_overflow_list == BUSY
ysr@969	1300	last->set_klass_to_list_ptr(NULL);
ysr@969	1301	}
ysr@969	1302	observed_overflow_list =
ysr@969	1303	(oop)Atomic::cmpxchg_ptr(suffix, &_overflow_list, cur_overflow_list);
ysr@969	1304	} while (cur_overflow_list != observed_overflow_list);
duke@435	1305	}
duke@435	1306	}
duke@435	1307
duke@435	1308	// Push objects on prefix list onto this thread's work queue
ysr@969	1309	assert(prefix != NULL && prefix != BUSY, "program logic");
duke@435	1310	cur = prefix;
ysr@969	1311	ssize_t n = 0;
duke@435	1312	while (cur != NULL) {
duke@435	1313	oop obj_to_push = cur->forwardee();
ysr@889	1314	oop next = oop(cur->klass_or_null());
duke@435	1315	cur->set_klass(obj_to_push->klass());
ysr@969	1316	// This may be an array object that is self-forwarded. In that case, the list pointer
ysr@969	1317	// space, cur, is not in the Java heap, but rather in the C-heap and should be freed.
ysr@969	1318	if (!is_in_reserved(cur)) {
ysr@969	1319	// This can become a scaling bottleneck when there is work queue overflow coincident
ysr@969	1320	// with promotion failure.
ysr@969	1321	oopDesc* f = cur;
ysr@969	1322	FREE_C_HEAP_ARRAY(oopDesc, f);
ysr@969	1323	} else if (par_scan_state->should_be_partially_scanned(obj_to_push, cur)) {
ysr@969	1324	assert(arrayOop(cur)->length() == 0, "entire array remaining to be scanned");
duke@435	1325	obj_to_push = cur;
duke@435	1326	}
ysr@969	1327	bool ok = work_q->push(obj_to_push);
ysr@969	1328	assert(ok, "Should have succeeded");
duke@435	1329	cur = next;
duke@435	1330	n++;
duke@435	1331	}
duke@435	1332	par_scan_state->note_overflow_refill(n);
ysr@969	1333	#ifndef PRODUCT
ysr@969	1334	assert(_num_par_pushes >= n, "Too many pops?");
ysr@969	1335	Atomic::add_ptr(-(intptr_t)n, &_num_par_pushes);
ysr@969	1336	#endif
duke@435	1337	return true;
duke@435	1338	}
ysr@969	1339	#undef BUSY
duke@435	1340
duke@435	1341	void ParNewGeneration::ref_processor_init()
duke@435	1342	{
duke@435	1343	if (_ref_processor == NULL) {
duke@435	1344	// Allocate and initialize a reference processor
duke@435	1345	_ref_processor = ReferenceProcessor::create_ref_processor(
duke@435	1346	_reserved, // span
duke@435	1347	refs_discovery_is_atomic(), // atomic_discovery
duke@435	1348	refs_discovery_is_mt(), // mt_discovery
duke@435	1349	NULL, // is_alive_non_header
duke@435	1350	ParallelGCThreads,
duke@435	1351	ParallelRefProcEnabled);
duke@435	1352	}
duke@435	1353	}
duke@435	1354
duke@435	1355	const char* ParNewGeneration::name() const {
duke@435	1356	return "par new generation";
duke@435	1357	}