1 /* 2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 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 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_CMS_PARNEWGENERATION_HPP 26 #define SHARE_VM_GC_CMS_PARNEWGENERATION_HPP 27 28 #include "gc/cms/parOopClosures.hpp" 29 #include "gc/serial/defNewGeneration.hpp" 30 #include "gc/shared/copyFailedInfo.hpp" 31 #include "gc/shared/gcTrace.hpp" 32 #include "gc/shared/plab.hpp" 33 #include "gc/shared/preservedMarks.hpp" 34 #include "gc/shared/taskqueue.hpp" 35 #include "memory/padded.hpp" 36 37 class ChunkArray; 38 class ParScanWithoutBarrierClosure; 39 class ParScanWithBarrierClosure; 40 class ParRootScanWithoutBarrierClosure; 41 class ParRootScanWithBarrierTwoGensClosure; 42 class ParEvacuateFollowersClosure; 43 class StrongRootsScope; 44 45 // It would be better if these types could be kept local to the .cpp file, 46 // but they must be here to allow ParScanClosure::do_oop_work to be defined 47 // in genOopClosures.inline.hpp. 48 49 typedef Padded<OopTaskQueue> ObjToScanQueue; 50 typedef GenericTaskQueueSet<ObjToScanQueue, mtGC> ObjToScanQueueSet; 51 52 class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure { 53 private: 54 ParScanWeakRefClosure* _par_cl; 55 protected: 56 template <class T> void do_oop_work(T* p); 57 public: 58 ParKeepAliveClosure(ParScanWeakRefClosure* cl); 59 virtual void do_oop(oop* p); 60 virtual void do_oop(narrowOop* p); 61 }; 62 63 // The state needed by thread performing parallel young-gen collection. 64 class ParScanThreadState { 65 friend class ParScanThreadStateSet; 66 private: 67 ObjToScanQueue *_work_queue; 68 Stack<oop, mtGC>* const _overflow_stack; 69 PreservedMarks* const _preserved_marks; 70 71 PLAB _to_space_alloc_buffer; 72 73 ParScanWithoutBarrierClosure _to_space_closure; // scan_without_gc_barrier 74 ParScanWithBarrierClosure _old_gen_closure; // scan_with_gc_barrier 75 ParRootScanWithoutBarrierClosure _to_space_root_closure; // scan_root_without_gc_barrier 76 // Will be passed to process_roots to set its generation. 77 ParRootScanWithBarrierTwoGensClosure _older_gen_closure; 78 // This closure will always be bound to the old gen; it will be used 79 // in evacuate_followers. 80 ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier 81 ParEvacuateFollowersClosure _evacuate_followers; 82 DefNewGeneration::IsAliveClosure _is_alive_closure; 83 ParScanWeakRefClosure _scan_weak_ref_closure; 84 ParKeepAliveClosure _keep_alive_closure; 85 86 Space* _to_space; 87 Space* to_space() { return _to_space; } 88 89 ParNewGeneration* _young_gen; 90 ParNewGeneration* young_gen() const { return _young_gen; } 91 92 Generation* _old_gen; 93 Generation* old_gen() { return _old_gen; } 94 95 HeapWord *_young_old_boundary; 96 97 int _hash_seed; 98 int _thread_num; 99 AgeTable _ageTable; 100 101 bool _to_space_full; 102 103 #if TASKQUEUE_STATS 104 size_t _term_attempts; 105 size_t _overflow_refills; 106 size_t _overflow_refill_objs; 107 #endif // TASKQUEUE_STATS 108 109 // Stats for promotion failure 110 PromotionFailedInfo _promotion_failed_info; 111 112 // Timing numbers. 113 double _start; 114 double _start_strong_roots; 115 double _strong_roots_time; 116 double _start_term; 117 double _term_time; 118 119 // Helper for trim_queues. Scans subset of an array and makes 120 // remainder available for work stealing. 121 void scan_partial_array_and_push_remainder(oop obj); 122 123 // In support of CMS' parallel rescan of survivor space. 124 ChunkArray* _survivor_chunk_array; 125 ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; } 126 127 void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size); 128 129 ParScanThreadState(Space* to_space_, ParNewGeneration* gen_, 130 Generation* old_gen_, int thread_num_, 131 ObjToScanQueueSet* work_queue_set_, 132 Stack<oop, mtGC>* overflow_stacks_, 133 PreservedMarks* preserved_marks_, 134 size_t desired_plab_sz_, 135 ParallelTaskTerminator& term_); 136 137 public: 138 AgeTable* age_table() {return &_ageTable;} 139 140 ObjToScanQueue* work_queue() { return _work_queue; } 141 142 PreservedMarks* preserved_marks() const { return _preserved_marks; } 143 144 PLAB* to_space_alloc_buffer() { 145 return &_to_space_alloc_buffer; 146 } 147 148 ParEvacuateFollowersClosure& evacuate_followers_closure() { return _evacuate_followers; } 149 DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; } 150 ParScanWeakRefClosure& scan_weak_ref_closure() { return _scan_weak_ref_closure; } 151 ParKeepAliveClosure& keep_alive_closure() { return _keep_alive_closure; } 152 ParScanClosure& older_gen_closure() { return _older_gen_closure; } 153 ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; }; 154 155 // Decrease queue size below "max_size". 156 void trim_queues(int max_size); 157 158 // Private overflow stack usage 159 Stack<oop, mtGC>* overflow_stack() { return _overflow_stack; } 160 bool take_from_overflow_stack(); 161 void push_on_overflow_stack(oop p); 162 163 // Is new_obj a candidate for scan_partial_array_and_push_remainder method. 164 inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const; 165 166 int* hash_seed() { return &_hash_seed; } 167 int thread_num() { return _thread_num; } 168 169 // Allocate a to-space block of size "sz", or else return NULL. 170 HeapWord* alloc_in_to_space_slow(size_t word_sz); 171 172 inline HeapWord* alloc_in_to_space(size_t word_sz); 173 174 HeapWord* young_old_boundary() { return _young_old_boundary; } 175 176 void set_young_old_boundary(HeapWord *boundary) { 177 _young_old_boundary = boundary; 178 } 179 180 // Undo the most recent allocation ("obj", of "word_sz"). 181 void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz); 182 183 // Promotion failure stats 184 void register_promotion_failure(size_t sz) { 185 _promotion_failed_info.register_copy_failure(sz); 186 } 187 PromotionFailedInfo& promotion_failed_info() { 188 return _promotion_failed_info; 189 } 190 bool promotion_failed() { 191 return _promotion_failed_info.has_failed(); 192 } 193 void print_promotion_failure_size(); 194 195 #if TASKQUEUE_STATS 196 TaskQueueStats & taskqueue_stats() const { return _work_queue->stats; } 197 198 size_t term_attempts() const { return _term_attempts; } 199 size_t overflow_refills() const { return _overflow_refills; } 200 size_t overflow_refill_objs() const { return _overflow_refill_objs; } 201 202 void note_term_attempt() { ++_term_attempts; } 203 void note_overflow_refill(size_t objs) { 204 ++_overflow_refills; _overflow_refill_objs += objs; 205 } 206 207 void reset_stats(); 208 #endif // TASKQUEUE_STATS 209 210 void start_strong_roots() { 211 _start_strong_roots = os::elapsedTime(); 212 } 213 void end_strong_roots() { 214 _strong_roots_time += (os::elapsedTime() - _start_strong_roots); 215 } 216 double strong_roots_time() const { return _strong_roots_time; } 217 void start_term_time() { 218 TASKQUEUE_STATS_ONLY(note_term_attempt()); 219 _start_term = os::elapsedTime(); 220 } 221 void end_term_time() { 222 _term_time += (os::elapsedTime() - _start_term); 223 } 224 double term_time() const { return _term_time; } 225 226 double elapsed_time() const { 227 return os::elapsedTime() - _start; 228 } 229 }; 230 231 class ParNewGenTask: public AbstractGangTask { 232 private: 233 ParNewGeneration* _young_gen; 234 Generation* _old_gen; 235 HeapWord* _young_old_boundary; 236 class ParScanThreadStateSet* _state_set; 237 StrongRootsScope* _strong_roots_scope; 238 239 public: 240 ParNewGenTask(ParNewGeneration* young_gen, 241 Generation* old_gen, 242 HeapWord* young_old_boundary, 243 ParScanThreadStateSet* state_set, 244 StrongRootsScope* strong_roots_scope); 245 246 HeapWord* young_old_boundary() { return _young_old_boundary; } 247 248 void work(uint worker_id); 249 }; 250 251 class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure { 252 protected: 253 template <class T> void do_oop_work(T* p); 254 public: 255 KeepAliveClosure(ScanWeakRefClosure* cl); 256 virtual void do_oop(oop* p); 257 virtual void do_oop(narrowOop* p); 258 }; 259 260 class EvacuateFollowersClosureGeneral: public VoidClosure { 261 private: 262 GenCollectedHeap* _gch; 263 OopsInGenClosure* _scan_cur_or_nonheap; 264 OopsInGenClosure* _scan_older; 265 public: 266 EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, 267 OopsInGenClosure* cur, 268 OopsInGenClosure* older); 269 virtual void do_void(); 270 }; 271 272 // Closure for scanning ParNewGeneration. 273 // Same as ScanClosure, except does parallel GC barrier. 274 class ScanClosureWithParBarrier: public ScanClosure { 275 protected: 276 template <class T> void do_oop_work(T* p); 277 public: 278 ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier); 279 virtual void do_oop(oop* p); 280 virtual void do_oop(narrowOop* p); 281 }; 282 283 // Implements AbstractRefProcTaskExecutor for ParNew. 284 class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor { 285 private: 286 ParNewGeneration& _young_gen; 287 Generation& _old_gen; 288 ParScanThreadStateSet& _state_set; 289 public: 290 ParNewRefProcTaskExecutor(ParNewGeneration& young_gen, 291 Generation& old_gen, 292 ParScanThreadStateSet& state_set) 293 : _young_gen(young_gen), _old_gen(old_gen), _state_set(state_set) 294 { } 295 296 // Executes a task using worker threads. 297 virtual void execute(ProcessTask& task); 298 virtual void execute(EnqueueTask& task); 299 // Switch to single threaded mode. 300 virtual void set_single_threaded_mode(); 301 }; 302 303 304 // A Generation that does parallel young-gen collection. 305 306 class ParNewGeneration: public DefNewGeneration { 307 friend class ParNewGenTask; 308 friend class ParNewRefProcTask; 309 friend class ParNewRefProcTaskExecutor; 310 friend class ParScanThreadStateSet; 311 friend class ParEvacuateFollowersClosure; 312 313 private: 314 // The per-worker-thread work queues 315 ObjToScanQueueSet* _task_queues; 316 317 // Per-worker-thread local overflow stacks 318 Stack<oop, mtGC>* _overflow_stacks; 319 320 // Desired size of survivor space plab's 321 PLABStats _plab_stats; 322 323 // A list of from-space images of to-be-scanned objects, threaded through 324 // klass-pointers (klass information already copied to the forwarded 325 // image.) Manipulated with CAS. 326 oop _overflow_list; 327 NOT_PRODUCT(ssize_t _num_par_pushes;) 328 329 // This closure is used by the reference processor to filter out 330 // references to live referent. 331 DefNewGeneration::IsAliveClosure _is_alive_closure; 332 333 // GC tracer that should be used during collection. 334 ParNewTracer _gc_tracer; 335 336 static oop real_forwardee_slow(oop obj); 337 static void waste_some_time(); 338 339 void handle_promotion_failed(GenCollectedHeap* gch, ParScanThreadStateSet& thread_state_set); 340 341 protected: 342 343 bool _survivor_overflow; 344 345 bool survivor_overflow() { return _survivor_overflow; } 346 void set_survivor_overflow(bool v) { _survivor_overflow = v; } 347 348 public: 349 ParNewGeneration(ReservedSpace rs, size_t initial_byte_size); 350 351 ~ParNewGeneration() { 352 for (uint i = 0; i < ParallelGCThreads; i++) 353 delete _task_queues->queue(i); 354 355 delete _task_queues; 356 } 357 358 virtual void ref_processor_init(); 359 virtual Generation::Name kind() { return Generation::ParNew; } 360 virtual const char* name() const; 361 virtual const char* short_name() const { return "ParNew"; } 362 363 // override 364 virtual bool refs_discovery_is_mt() const { 365 return ParallelGCThreads > 1; 366 } 367 368 // Make the collection virtual. 369 virtual void collect(bool full, 370 bool clear_all_soft_refs, 371 size_t size, 372 bool is_tlab); 373 374 // This needs to be visible to the closure function. 375 // "obj" is the object to be copied, "m" is a recent value of its mark 376 // that must not contain a forwarding pointer (though one might be 377 // inserted in "obj"s mark word by a parallel thread). 378 oop copy_to_survivor_space(ParScanThreadState* par_scan_state, 379 oop obj, size_t obj_sz, markOop m); 380 381 // in support of testing overflow code 382 NOT_PRODUCT(int _overflow_counter;) 383 NOT_PRODUCT(bool should_simulate_overflow();) 384 385 // Accessor for overflow list 386 oop overflow_list() { return _overflow_list; } 387 388 // Push the given (from-space) object on the global overflow list. 389 void push_on_overflow_list(oop from_space_obj, ParScanThreadState* par_scan_state); 390 391 // If the global overflow list is non-empty, move some tasks from it 392 // onto "work_q" (which need not be empty). No more than 1/4 of the 393 // available space on "work_q" is used. 394 bool take_from_overflow_list(ParScanThreadState* par_scan_state); 395 bool take_from_overflow_list_work(ParScanThreadState* par_scan_state); 396 397 // The task queues to be used by parallel GC threads. 398 ObjToScanQueueSet* task_queues() { 399 return _task_queues; 400 } 401 402 PLABStats* plab_stats() { 403 return &_plab_stats; 404 } 405 406 size_t desired_plab_sz(); 407 408 const ParNewTracer* gc_tracer() const { 409 return &_gc_tracer; 410 } 411 412 static oop real_forwardee(oop obj); 413 }; 414 415 #endif // SHARE_VM_GC_CMS_PARNEWGENERATION_HPP