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duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 2001-2007 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 | class ChunkArray; |
duke@435 | 26 | class ParScanWithoutBarrierClosure; |
duke@435 | 27 | class ParScanWithBarrierClosure; |
duke@435 | 28 | class ParRootScanWithoutBarrierClosure; |
duke@435 | 29 | class ParRootScanWithBarrierTwoGensClosure; |
duke@435 | 30 | class ParEvacuateFollowersClosure; |
duke@435 | 31 | |
duke@435 | 32 | // It would be better if these types could be kept local to the .cpp file, |
duke@435 | 33 | // but they must be here to allow ParScanClosure::do_oop_work to be defined |
duke@435 | 34 | // in genOopClosures.inline.hpp. |
duke@435 | 35 | |
duke@435 | 36 | |
duke@435 | 37 | typedef OopTaskQueue ObjToScanQueue; |
duke@435 | 38 | typedef OopTaskQueueSet ObjToScanQueueSet; |
duke@435 | 39 | |
duke@435 | 40 | // Enable this to get push/pop/steal stats. |
duke@435 | 41 | const int PAR_STATS_ENABLED = 0; |
duke@435 | 42 | |
duke@435 | 43 | class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure { |
duke@435 | 44 | ParScanWeakRefClosure* _par_cl; |
duke@435 | 45 | public: |
duke@435 | 46 | ParKeepAliveClosure(ParScanWeakRefClosure* cl); |
duke@435 | 47 | void do_oop(oop* p); |
duke@435 | 48 | }; |
duke@435 | 49 | |
duke@435 | 50 | // The state needed by thread performing parallel young-gen collection. |
duke@435 | 51 | class ParScanThreadState { |
duke@435 | 52 | friend class ParScanThreadStateSet; |
duke@435 | 53 | ObjToScanQueue *_work_queue; |
duke@435 | 54 | |
duke@435 | 55 | ParGCAllocBuffer _to_space_alloc_buffer; |
duke@435 | 56 | |
duke@435 | 57 | ParScanWithoutBarrierClosure _to_space_closure; // scan_without_gc_barrier |
duke@435 | 58 | ParScanWithBarrierClosure _old_gen_closure; // scan_with_gc_barrier |
duke@435 | 59 | ParRootScanWithoutBarrierClosure _to_space_root_closure; // scan_root_without_gc_barrier |
duke@435 | 60 | // One of these two will be passed to process_strong_roots, which will |
duke@435 | 61 | // set its generation. The first is for two-gen configs where the |
duke@435 | 62 | // old gen collects the perm gen; the second is for arbitrary configs. |
duke@435 | 63 | // The second isn't used right now (it used to be used for the train, an |
duke@435 | 64 | // incremental collector) but the declaration has been left as a reminder. |
duke@435 | 65 | ParRootScanWithBarrierTwoGensClosure _older_gen_closure; |
duke@435 | 66 | // This closure will always be bound to the old gen; it will be used |
duke@435 | 67 | // in evacuate_followers. |
duke@435 | 68 | ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier |
duke@435 | 69 | ParEvacuateFollowersClosure _evacuate_followers; |
duke@435 | 70 | DefNewGeneration::IsAliveClosure _is_alive_closure; |
duke@435 | 71 | ParScanWeakRefClosure _scan_weak_ref_closure; |
duke@435 | 72 | ParKeepAliveClosure _keep_alive_closure; |
duke@435 | 73 | |
duke@435 | 74 | |
duke@435 | 75 | Space* _to_space; |
duke@435 | 76 | Space* to_space() { return _to_space; } |
duke@435 | 77 | |
duke@435 | 78 | Generation* _old_gen; |
duke@435 | 79 | Generation* old_gen() { return _old_gen; } |
duke@435 | 80 | |
duke@435 | 81 | HeapWord *_young_old_boundary; |
duke@435 | 82 | |
duke@435 | 83 | int _hash_seed; |
duke@435 | 84 | int _thread_num; |
duke@435 | 85 | ageTable _ageTable; |
duke@435 | 86 | |
duke@435 | 87 | bool _to_space_full; |
duke@435 | 88 | |
duke@435 | 89 | int _pushes, _pops, _steals, _steal_attempts, _term_attempts; |
duke@435 | 90 | int _overflow_pushes, _overflow_refills, _overflow_refill_objs; |
duke@435 | 91 | |
duke@435 | 92 | // Timing numbers. |
duke@435 | 93 | double _start; |
duke@435 | 94 | double _start_strong_roots; |
duke@435 | 95 | double _strong_roots_time; |
duke@435 | 96 | double _start_term; |
duke@435 | 97 | double _term_time; |
duke@435 | 98 | |
duke@435 | 99 | // Helper for trim_queues. Scans subset of an array and makes |
duke@435 | 100 | // remainder available for work stealing. |
duke@435 | 101 | void scan_partial_array_and_push_remainder(oop obj); |
duke@435 | 102 | |
duke@435 | 103 | // In support of CMS' parallel rescan of survivor space. |
duke@435 | 104 | ChunkArray* _survivor_chunk_array; |
duke@435 | 105 | ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; } |
duke@435 | 106 | |
duke@435 | 107 | void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size); |
duke@435 | 108 | |
duke@435 | 109 | ParScanThreadState(Space* to_space_, ParNewGeneration* gen_, |
duke@435 | 110 | Generation* old_gen_, int thread_num_, |
duke@435 | 111 | ObjToScanQueueSet* work_queue_set_, size_t desired_plab_sz_, |
duke@435 | 112 | ParallelTaskTerminator& term_); |
duke@435 | 113 | |
duke@435 | 114 | public: |
duke@435 | 115 | ageTable* age_table() {return &_ageTable;} |
duke@435 | 116 | |
duke@435 | 117 | ObjToScanQueue* work_queue() { return _work_queue; } |
duke@435 | 118 | |
duke@435 | 119 | ParGCAllocBuffer* to_space_alloc_buffer() { |
duke@435 | 120 | return &_to_space_alloc_buffer; |
duke@435 | 121 | } |
duke@435 | 122 | |
duke@435 | 123 | ParEvacuateFollowersClosure& evacuate_followers_closure() { return _evacuate_followers; } |
duke@435 | 124 | DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; } |
duke@435 | 125 | ParScanWeakRefClosure& scan_weak_ref_closure() { return _scan_weak_ref_closure; } |
duke@435 | 126 | ParKeepAliveClosure& keep_alive_closure() { return _keep_alive_closure; } |
duke@435 | 127 | ParScanClosure& older_gen_closure() { return _older_gen_closure; } |
duke@435 | 128 | ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; }; |
duke@435 | 129 | |
duke@435 | 130 | // Decrease queue size below "max_size". |
duke@435 | 131 | void trim_queues(int max_size); |
duke@435 | 132 | |
duke@435 | 133 | // Is new_obj a candidate for scan_partial_array_and_push_remainder method. |
duke@435 | 134 | inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const; |
duke@435 | 135 | |
duke@435 | 136 | int* hash_seed() { return &_hash_seed; } |
duke@435 | 137 | int thread_num() { return _thread_num; } |
duke@435 | 138 | |
duke@435 | 139 | // Allocate a to-space block of size "sz", or else return NULL. |
duke@435 | 140 | HeapWord* alloc_in_to_space_slow(size_t word_sz); |
duke@435 | 141 | |
duke@435 | 142 | HeapWord* alloc_in_to_space(size_t word_sz) { |
duke@435 | 143 | HeapWord* obj = to_space_alloc_buffer()->allocate(word_sz); |
duke@435 | 144 | if (obj != NULL) return obj; |
duke@435 | 145 | else return alloc_in_to_space_slow(word_sz); |
duke@435 | 146 | } |
duke@435 | 147 | |
duke@435 | 148 | HeapWord* young_old_boundary() { return _young_old_boundary; } |
duke@435 | 149 | |
duke@435 | 150 | void set_young_old_boundary(HeapWord *boundary) { |
duke@435 | 151 | _young_old_boundary = boundary; |
duke@435 | 152 | } |
duke@435 | 153 | |
duke@435 | 154 | // Undo the most recent allocation ("obj", of "word_sz"). |
duke@435 | 155 | void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz); |
duke@435 | 156 | |
duke@435 | 157 | int pushes() { return _pushes; } |
duke@435 | 158 | int pops() { return _pops; } |
duke@435 | 159 | int steals() { return _steals; } |
duke@435 | 160 | int steal_attempts() { return _steal_attempts; } |
duke@435 | 161 | int term_attempts() { return _term_attempts; } |
duke@435 | 162 | int overflow_pushes() { return _overflow_pushes; } |
duke@435 | 163 | int overflow_refills() { return _overflow_refills; } |
duke@435 | 164 | int overflow_refill_objs() { return _overflow_refill_objs; } |
duke@435 | 165 | |
duke@435 | 166 | void note_push() { if (PAR_STATS_ENABLED) _pushes++; } |
duke@435 | 167 | void note_pop() { if (PAR_STATS_ENABLED) _pops++; } |
duke@435 | 168 | void note_steal() { if (PAR_STATS_ENABLED) _steals++; } |
duke@435 | 169 | void note_steal_attempt() { if (PAR_STATS_ENABLED) _steal_attempts++; } |
duke@435 | 170 | void note_term_attempt() { if (PAR_STATS_ENABLED) _term_attempts++; } |
duke@435 | 171 | void note_overflow_push() { if (PAR_STATS_ENABLED) _overflow_pushes++; } |
duke@435 | 172 | void note_overflow_refill(int objs) { |
duke@435 | 173 | if (PAR_STATS_ENABLED) { |
duke@435 | 174 | _overflow_refills++; |
duke@435 | 175 | _overflow_refill_objs += objs; |
duke@435 | 176 | } |
duke@435 | 177 | } |
duke@435 | 178 | |
duke@435 | 179 | void start_strong_roots() { |
duke@435 | 180 | _start_strong_roots = os::elapsedTime(); |
duke@435 | 181 | } |
duke@435 | 182 | void end_strong_roots() { |
duke@435 | 183 | _strong_roots_time += (os::elapsedTime() - _start_strong_roots); |
duke@435 | 184 | } |
duke@435 | 185 | double strong_roots_time() { return _strong_roots_time; } |
duke@435 | 186 | void start_term_time() { |
duke@435 | 187 | note_term_attempt(); |
duke@435 | 188 | _start_term = os::elapsedTime(); |
duke@435 | 189 | } |
duke@435 | 190 | void end_term_time() { |
duke@435 | 191 | _term_time += (os::elapsedTime() - _start_term); |
duke@435 | 192 | } |
duke@435 | 193 | double term_time() { return _term_time; } |
duke@435 | 194 | |
duke@435 | 195 | double elapsed() { |
duke@435 | 196 | return os::elapsedTime() - _start; |
duke@435 | 197 | } |
duke@435 | 198 | |
duke@435 | 199 | }; |
duke@435 | 200 | |
duke@435 | 201 | class ParNewGenTask: public AbstractGangTask { |
duke@435 | 202 | ParNewGeneration* _gen; |
duke@435 | 203 | Generation* _next_gen; |
duke@435 | 204 | HeapWord* _young_old_boundary; |
duke@435 | 205 | class ParScanThreadStateSet* _state_set; |
duke@435 | 206 | |
duke@435 | 207 | public: |
duke@435 | 208 | ParNewGenTask(ParNewGeneration* gen, |
duke@435 | 209 | Generation* next_gen, |
duke@435 | 210 | HeapWord* young_old_boundary, |
duke@435 | 211 | ParScanThreadStateSet* state_set); |
duke@435 | 212 | |
duke@435 | 213 | HeapWord* young_old_boundary() { return _young_old_boundary; } |
duke@435 | 214 | |
duke@435 | 215 | void work(int i); |
duke@435 | 216 | }; |
duke@435 | 217 | |
duke@435 | 218 | class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure { |
duke@435 | 219 | public: |
duke@435 | 220 | KeepAliveClosure(ScanWeakRefClosure* cl); |
duke@435 | 221 | void do_oop(oop* p); |
duke@435 | 222 | }; |
duke@435 | 223 | |
duke@435 | 224 | class EvacuateFollowersClosureGeneral: public VoidClosure { |
duke@435 | 225 | GenCollectedHeap* _gch; |
duke@435 | 226 | int _level; |
duke@435 | 227 | OopsInGenClosure* _scan_cur_or_nonheap; |
duke@435 | 228 | OopsInGenClosure* _scan_older; |
duke@435 | 229 | public: |
duke@435 | 230 | EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, int level, |
duke@435 | 231 | OopsInGenClosure* cur, |
duke@435 | 232 | OopsInGenClosure* older); |
duke@435 | 233 | void do_void(); |
duke@435 | 234 | }; |
duke@435 | 235 | |
duke@435 | 236 | // Closure for scanning ParNewGeneration. |
duke@435 | 237 | // Same as ScanClosure, except does parallel GC barrier. |
duke@435 | 238 | class ScanClosureWithParBarrier: public ScanClosure { |
duke@435 | 239 | public: |
duke@435 | 240 | ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier); |
duke@435 | 241 | void do_oop(oop* p); |
duke@435 | 242 | }; |
duke@435 | 243 | |
duke@435 | 244 | // Implements AbstractRefProcTaskExecutor for ParNew. |
duke@435 | 245 | class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor { |
duke@435 | 246 | public: |
duke@435 | 247 | |
duke@435 | 248 | ParNewRefProcTaskExecutor(ParNewGeneration& generation, |
duke@435 | 249 | ParScanThreadStateSet& state_set) |
duke@435 | 250 | : _generation(generation), _state_set(state_set) |
duke@435 | 251 | { } |
duke@435 | 252 | |
duke@435 | 253 | // Executes a task using worker threads. |
duke@435 | 254 | virtual void execute(ProcessTask& task); |
duke@435 | 255 | virtual void execute(EnqueueTask& task); |
duke@435 | 256 | // Switch to single threaded mode. |
duke@435 | 257 | virtual void set_single_threaded_mode(); |
duke@435 | 258 | private: |
duke@435 | 259 | ParNewGeneration& _generation; |
duke@435 | 260 | ParScanThreadStateSet& _state_set; |
duke@435 | 261 | }; |
duke@435 | 262 | |
duke@435 | 263 | |
duke@435 | 264 | // A Generation that does parallel young-gen collection. |
duke@435 | 265 | |
duke@435 | 266 | class ParNewGeneration: public DefNewGeneration { |
duke@435 | 267 | friend class ParNewGenTask; |
duke@435 | 268 | friend class ParNewRefProcTask; |
duke@435 | 269 | friend class ParNewRefProcTaskExecutor; |
duke@435 | 270 | friend class ParScanThreadStateSet; |
duke@435 | 271 | |
duke@435 | 272 | // XXX use a global constant instead of 64! |
duke@435 | 273 | struct ObjToScanQueuePadded { |
duke@435 | 274 | ObjToScanQueue work_queue; |
duke@435 | 275 | char pad[64 - sizeof(ObjToScanQueue)]; // prevent false sharing |
duke@435 | 276 | }; |
duke@435 | 277 | |
duke@435 | 278 | // The per-thread work queues, available here for stealing. |
duke@435 | 279 | ObjToScanQueueSet* _task_queues; |
duke@435 | 280 | |
duke@435 | 281 | // Desired size of survivor space plab's |
duke@435 | 282 | PLABStats _plab_stats; |
duke@435 | 283 | |
duke@435 | 284 | // A list of from-space images of to-be-scanned objects, threaded through |
duke@435 | 285 | // klass-pointers (klass information already copied to the forwarded |
duke@435 | 286 | // image.) Manipulated with CAS. |
duke@435 | 287 | oop _overflow_list; |
duke@435 | 288 | |
duke@435 | 289 | // If true, older generation does not support promotion undo, so avoid. |
duke@435 | 290 | static bool _avoid_promotion_undo; |
duke@435 | 291 | |
duke@435 | 292 | // This closure is used by the reference processor to filter out |
duke@435 | 293 | // references to live referent. |
duke@435 | 294 | DefNewGeneration::IsAliveClosure _is_alive_closure; |
duke@435 | 295 | |
duke@435 | 296 | static oop real_forwardee_slow(oop obj); |
duke@435 | 297 | static void waste_some_time(); |
duke@435 | 298 | |
duke@435 | 299 | // Preserve the mark of "obj", if necessary, in preparation for its mark |
duke@435 | 300 | // word being overwritten with a self-forwarding-pointer. |
duke@435 | 301 | void preserve_mark_if_necessary(oop obj, markOop m); |
duke@435 | 302 | |
duke@435 | 303 | protected: |
duke@435 | 304 | |
duke@435 | 305 | bool _survivor_overflow; |
duke@435 | 306 | |
duke@435 | 307 | bool avoid_promotion_undo() { return _avoid_promotion_undo; } |
duke@435 | 308 | void set_avoid_promotion_undo(bool v) { _avoid_promotion_undo = v; } |
duke@435 | 309 | |
duke@435 | 310 | bool survivor_overflow() { return _survivor_overflow; } |
duke@435 | 311 | void set_survivor_overflow(bool v) { _survivor_overflow = v; } |
duke@435 | 312 | |
duke@435 | 313 | // Adjust the tenuring threshold. See the implementation for |
duke@435 | 314 | // the details of the policy. |
duke@435 | 315 | virtual void adjust_desired_tenuring_threshold(); |
duke@435 | 316 | |
duke@435 | 317 | public: |
duke@435 | 318 | ParNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level); |
duke@435 | 319 | |
duke@435 | 320 | ~ParNewGeneration() { |
duke@435 | 321 | for (uint i = 0; i < ParallelGCThreads; i++) |
duke@435 | 322 | delete _task_queues->queue(i); |
duke@435 | 323 | |
duke@435 | 324 | delete _task_queues; |
duke@435 | 325 | } |
duke@435 | 326 | |
duke@435 | 327 | virtual void ref_processor_init(); |
duke@435 | 328 | virtual Generation::Name kind() { return Generation::ParNew; } |
duke@435 | 329 | virtual const char* name() const; |
duke@435 | 330 | virtual const char* short_name() const { return "ParNew"; } |
duke@435 | 331 | |
duke@435 | 332 | // override |
duke@435 | 333 | virtual bool refs_discovery_is_mt() const { |
duke@435 | 334 | assert(UseParNewGC, "ParNewGeneration only when UseParNewGC"); |
duke@435 | 335 | return ParallelGCThreads > 1; |
duke@435 | 336 | } |
duke@435 | 337 | |
duke@435 | 338 | // Make the collection virtual. |
duke@435 | 339 | virtual void collect(bool full, |
duke@435 | 340 | bool clear_all_soft_refs, |
duke@435 | 341 | size_t size, |
duke@435 | 342 | bool is_tlab); |
duke@435 | 343 | |
duke@435 | 344 | // This needs to be visible to the closure function. |
duke@435 | 345 | // "obj" is the object to be copied, "m" is a recent value of its mark |
duke@435 | 346 | // that must not contain a forwarding pointer (though one might be |
duke@435 | 347 | // inserted in "obj"s mark word by a parallel thread). |
duke@435 | 348 | inline oop copy_to_survivor_space(ParScanThreadState* par_scan_state, |
duke@435 | 349 | oop obj, size_t obj_sz, markOop m) { |
duke@435 | 350 | if (_avoid_promotion_undo) { |
duke@435 | 351 | return copy_to_survivor_space_avoiding_promotion_undo(par_scan_state, |
duke@435 | 352 | obj, obj_sz, m); |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | return copy_to_survivor_space_with_undo(par_scan_state, obj, obj_sz, m); |
duke@435 | 356 | } |
duke@435 | 357 | |
duke@435 | 358 | oop copy_to_survivor_space_avoiding_promotion_undo(ParScanThreadState* par_scan_state, |
duke@435 | 359 | oop obj, size_t obj_sz, markOop m); |
duke@435 | 360 | |
duke@435 | 361 | oop copy_to_survivor_space_with_undo(ParScanThreadState* par_scan_state, |
duke@435 | 362 | oop obj, size_t obj_sz, markOop m); |
duke@435 | 363 | |
duke@435 | 364 | // Push the given (from-space) object on the global overflow list. |
duke@435 | 365 | void push_on_overflow_list(oop from_space_obj); |
duke@435 | 366 | |
duke@435 | 367 | // If the global overflow list is non-empty, move some tasks from it |
duke@435 | 368 | // onto "work_q" (which must be empty). No more than 1/4 of the |
duke@435 | 369 | // max_elems of "work_q" are moved. |
duke@435 | 370 | bool take_from_overflow_list(ParScanThreadState* par_scan_state); |
duke@435 | 371 | |
duke@435 | 372 | // The task queues to be used by parallel GC threads. |
duke@435 | 373 | ObjToScanQueueSet* task_queues() { |
duke@435 | 374 | return _task_queues; |
duke@435 | 375 | } |
duke@435 | 376 | |
duke@435 | 377 | PLABStats* plab_stats() { |
duke@435 | 378 | return &_plab_stats; |
duke@435 | 379 | } |
duke@435 | 380 | |
duke@435 | 381 | size_t desired_plab_sz() { |
duke@435 | 382 | return _plab_stats.desired_plab_sz(); |
duke@435 | 383 | } |
duke@435 | 384 | |
duke@435 | 385 | static oop real_forwardee(oop obj); |
duke@435 | 386 | |
duke@435 | 387 | DEBUG_ONLY(static bool is_legal_forward_ptr(oop p);) |
duke@435 | 388 | }; |