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comparison src/share/vm/memory/referenceProcessor.hpp @ 2369:92da084fefc9

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6668573: CMS: reference processing crash if ParallelCMSThreads > ParallelGCThreads Summary: Use _max_num_q = max(discovery_degree, processing_degree), and let balance_queues() redistribute from discovery_degree to processing_degree of queues. This should also allow a more dynamic and flexible parallelism policy in the future. Reviewed-by: jmasa, johnc
author ysr
date Thu, 17 Mar 2011 10:32:46 -0700
parents 8df09fb45352
children c2bf0120ee5d
comparison
equal deleted inserted replaced
2368:dde920245681 2369:92da084fefc9
1 /* 1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. 2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 * 4 *
5 * This code is free software; you can redistribute it and/or modify it 5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as 6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. 7 * published by the Free Software Foundation.
69 bool _discovered_list_needs_barrier; 69 bool _discovered_list_needs_barrier;
70 BarrierSet* _bs; // Cached copy of BarrierSet. 70 BarrierSet* _bs; // Cached copy of BarrierSet.
71 bool _enqueuing_is_done; // true if all weak references enqueued 71 bool _enqueuing_is_done; // true if all weak references enqueued
72 bool _processing_is_mt; // true during phases when 72 bool _processing_is_mt; // true during phases when
73 // reference processing is MT. 73 // reference processing is MT.
74 int _next_id; // round-robin counter in 74 int _next_id; // round-robin mod _num_q counter in
75 // support of work distribution 75 // support of work distribution
76 76
77 // For collectors that do not keep GC marking information 77 // For collectors that do not keep GC marking information
78 // in the object header, this field holds a closure that 78 // in the object header, this field holds a closure that
79 // helps the reference processor determine the reachability 79 // helps the reference processor determine the reachability
101 DiscoveredList* _discoveredFinalRefs; 101 DiscoveredList* _discoveredFinalRefs;
102 DiscoveredList* _discoveredPhantomRefs; 102 DiscoveredList* _discoveredPhantomRefs;
103 103
104 public: 104 public:
105 int num_q() { return _num_q; } 105 int num_q() { return _num_q; }
106 void set_mt_degree(int v) { _num_q = v; } 106 int max_num_q() { return _max_num_q; }
107 void set_active_mt_degree(int v) { _num_q = v; }
107 DiscoveredList* discovered_soft_refs() { return _discoveredSoftRefs; } 108 DiscoveredList* discovered_soft_refs() { return _discoveredSoftRefs; }
108 static oop sentinel_ref() { return _sentinelRef; } 109 static oop sentinel_ref() { return _sentinelRef; }
109 static oop* adr_sentinel_ref() { return &_sentinelRef; } 110 static oop* adr_sentinel_ref() { return &_sentinelRef; }
110 ReferencePolicy* setup_policy(bool always_clear) { 111 ReferencePolicy* setup_policy(bool always_clear) {
111 _current_soft_ref_policy = always_clear ? 112 _current_soft_ref_policy = always_clear ?
214 BoolObjectClosure* is_alive, 215 BoolObjectClosure* is_alive,
215 OopClosure* keep_alive, 216 OopClosure* keep_alive,
216 VoidClosure* complete_gc, 217 VoidClosure* complete_gc,
217 YieldClosure* yield); 218 YieldClosure* yield);
218 219
220 // round-robin mod _num_q (not: _not_ mode _max_num_q)
219 int next_id() { 221 int next_id() {
220 int id = _next_id; 222 int id = _next_id;
221 if (++_next_id == _num_q) { 223 if (++_next_id == _num_q) {
222 _next_id = 0; 224 _next_id = 0;
223 } 225 }
254 _is_alive_non_header(NULL), 256 _is_alive_non_header(NULL),
255 _num_q(0), 257 _num_q(0),
256 _max_num_q(0), 258 _max_num_q(0),
257 _processing_is_mt(false), 259 _processing_is_mt(false),
258 _next_id(0) 260 _next_id(0)
259 {} 261 { }
260 262
261 ReferenceProcessor(MemRegion span, bool atomic_discovery, 263 // Default parameters give you a vanilla reference processor.
262 bool mt_discovery, 264 ReferenceProcessor(MemRegion span,
263 int mt_degree = 1, 265 bool mt_processing = false, int mt_processing_degree = 1,
264 bool mt_processing = false, 266 bool mt_discovery = false, int mt_discovery_degree = 1,
267 bool atomic_discovery = true,
268 BoolObjectClosure* is_alive_non_header = NULL,
265 bool discovered_list_needs_barrier = false); 269 bool discovered_list_needs_barrier = false);
266
267 // Allocates and initializes a reference processor.
268 static ReferenceProcessor* create_ref_processor(
269 MemRegion span,
270 bool atomic_discovery,
271 bool mt_discovery,
272 BoolObjectClosure* is_alive_non_header = NULL,
273 int parallel_gc_threads = 1,
274 bool mt_processing = false,
275 bool discovered_list_needs_barrier = false);
276 270
277 // RefDiscoveryPolicy values 271 // RefDiscoveryPolicy values
278 enum DiscoveryPolicy { 272 enum DiscoveryPolicy {
279 ReferenceBasedDiscovery = 0, 273 ReferenceBasedDiscovery = 0,
280 ReferentBasedDiscovery = 1, 274 ReferentBasedDiscovery = 1,
395 }; 389 };
396 390
397 // A utility class to temporarily change the MT'ness of 391 // A utility class to temporarily change the MT'ness of
398 // reference discovery for the given ReferenceProcessor 392 // reference discovery for the given ReferenceProcessor
399 // in the scope that contains it. 393 // in the scope that contains it.
400 class ReferenceProcessorMTMutator: StackObj { 394 class ReferenceProcessorMTDiscoveryMutator: StackObj {
401 private: 395 private:
402 ReferenceProcessor* _rp; 396 ReferenceProcessor* _rp;
403 bool _saved_mt; 397 bool _saved_mt;
404 398
405 public: 399 public:
406 ReferenceProcessorMTMutator(ReferenceProcessor* rp, 400 ReferenceProcessorMTDiscoveryMutator(ReferenceProcessor* rp,
407 bool mt): 401 bool mt):
408 _rp(rp) { 402 _rp(rp) {
409 _saved_mt = _rp->discovery_is_mt(); 403 _saved_mt = _rp->discovery_is_mt();
410 _rp->set_mt_discovery(mt); 404 _rp->set_mt_discovery(mt);
411 } 405 }
412 406
413 ~ReferenceProcessorMTMutator() { 407 ~ReferenceProcessorMTDiscoveryMutator() {
414 _rp->set_mt_discovery(_saved_mt); 408 _rp->set_mt_discovery(_saved_mt);
415 } 409 }
416 }; 410 };
417 411
418 412