Mercurial > hg > truffle
annotate src/share/vm/memory/genCollectedHeap.hpp @ 269:850fdf70db2b
Merge
| author | jmasa |
|---|---|
| date | Mon, 28 Jul 2008 15:30:23 -0700 |
| parents | d1605aabd0a1 12eea04c8b06 |
| children | 1ee8caae33af |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 196 | 2 * Copyright 2000-2008 Sun Microsystems, Inc. All Rights Reserved. |
| 0 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 class SubTasksDone; | |
| 26 | |
| 27 // A "GenCollectedHeap" is a SharedHeap that uses generational | |
| 28 // collection. It is represented with a sequence of Generation's. | |
| 29 class GenCollectedHeap : public SharedHeap { | |
| 30 friend class GenCollectorPolicy; | |
| 31 friend class Generation; | |
| 32 friend class DefNewGeneration; | |
| 33 friend class TenuredGeneration; | |
| 34 friend class ConcurrentMarkSweepGeneration; | |
| 35 friend class CMSCollector; | |
| 36 friend class GenMarkSweep; | |
| 37 friend class VM_GenCollectForAllocation; | |
|
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38 friend class VM_GenCollectForPermanentAllocation; |
| 0 | 39 friend class VM_GenCollectFull; |
| 40 friend class VM_GenCollectFullConcurrent; | |
| 41 friend class VM_GC_HeapInspection; | |
| 42 friend class VM_HeapDumper; | |
| 43 friend class HeapInspection; | |
| 44 friend class GCCauseSetter; | |
| 45 friend class VMStructs; | |
| 46 public: | |
| 47 enum SomeConstants { | |
| 48 max_gens = 10 | |
| 49 }; | |
| 50 | |
| 51 friend class VM_PopulateDumpSharedSpace; | |
| 52 | |
| 53 protected: | |
| 54 // Fields: | |
| 55 static GenCollectedHeap* _gch; | |
| 56 | |
| 57 private: | |
| 58 int _n_gens; | |
| 59 Generation* _gens[max_gens]; | |
| 60 GenerationSpec** _gen_specs; | |
| 61 | |
| 62 // The generational collector policy. | |
| 63 GenCollectorPolicy* _gen_policy; | |
| 64 | |
| 65 // If a generation would bail out of an incremental collection, | |
| 66 // it sets this flag. If the flag is set, satisfy_failed_allocation | |
| 67 // will attempt allocating in all generations before doing a full GC. | |
| 68 bool _incremental_collection_will_fail; | |
| 69 bool _last_incremental_collection_failed; | |
| 70 | |
| 71 // In support of ExplicitGCInvokesConcurrent functionality | |
| 72 unsigned int _full_collections_completed; | |
| 73 | |
| 74 // Data structure for claiming the (potentially) parallel tasks in | |
| 75 // (gen-specific) strong roots processing. | |
| 76 SubTasksDone* _gen_process_strong_tasks; | |
| 77 | |
| 78 // In block contents verification, the number of header words to skip | |
| 79 NOT_PRODUCT(static size_t _skip_header_HeapWords;) | |
| 80 | |
| 81 // GC is not allowed during the dump of the shared classes. Keep track | |
| 82 // of this in order to provide an reasonable error message when terminating. | |
| 83 bool _preloading_shared_classes; | |
| 84 | |
| 85 protected: | |
| 86 // Directs each generation up to and including "collectedGen" to recompute | |
| 87 // its desired size. | |
| 88 void compute_new_generation_sizes(int collectedGen); | |
| 89 | |
| 90 // Helper functions for allocation | |
| 91 HeapWord* attempt_allocation(size_t size, | |
| 92 bool is_tlab, | |
| 93 bool first_only); | |
| 94 | |
| 95 // Helper function for two callbacks below. | |
| 96 // Considers collection of the first max_level+1 generations. | |
| 97 void do_collection(bool full, | |
| 98 bool clear_all_soft_refs, | |
| 99 size_t size, | |
| 100 bool is_tlab, | |
| 101 int max_level); | |
| 102 | |
| 103 // Callback from VM_GenCollectForAllocation operation. | |
| 104 // This function does everything necessary/possible to satisfy an | |
| 105 // allocation request that failed in the youngest generation that should | |
| 106 // have handled it (including collection, expansion, etc.) | |
| 107 HeapWord* satisfy_failed_allocation(size_t size, bool is_tlab); | |
| 108 | |
| 109 // Callback from VM_GenCollectFull operation. | |
| 110 // Perform a full collection of the first max_level+1 generations. | |
| 111 void do_full_collection(bool clear_all_soft_refs, int max_level); | |
| 112 | |
| 113 // Does the "cause" of GC indicate that | |
| 114 // we absolutely __must__ clear soft refs? | |
| 115 bool must_clear_all_soft_refs(); | |
| 116 | |
| 117 public: | |
| 118 GenCollectedHeap(GenCollectorPolicy *policy); | |
| 119 | |
| 120 GCStats* gc_stats(int level) const; | |
| 121 | |
| 122 // Returns JNI_OK on success | |
| 123 virtual jint initialize(); | |
| 124 char* allocate(size_t alignment, PermanentGenerationSpec* perm_gen_spec, | |
| 125 size_t* _total_reserved, int* _n_covered_regions, | |
| 126 ReservedSpace* heap_rs); | |
| 127 | |
| 128 // Does operations required after initialization has been done. | |
| 129 void post_initialize(); | |
| 130 | |
| 131 // Initialize ("weak") refs processing support | |
| 132 virtual void ref_processing_init(); | |
| 133 | |
| 134 virtual CollectedHeap::Name kind() const { | |
| 135 return CollectedHeap::GenCollectedHeap; | |
| 136 } | |
| 137 | |
| 138 // The generational collector policy. | |
| 139 GenCollectorPolicy* gen_policy() const { return _gen_policy; } | |
| 140 | |
| 141 // Adaptive size policy | |
| 142 virtual AdaptiveSizePolicy* size_policy() { | |
| 143 return gen_policy()->size_policy(); | |
| 144 } | |
| 145 | |
| 146 size_t capacity() const; | |
| 147 size_t used() const; | |
| 148 | |
| 149 // Save the "used_region" for generations level and lower, | |
| 150 // and, if perm is true, for perm gen. | |
| 151 void save_used_regions(int level, bool perm); | |
| 152 | |
| 153 size_t max_capacity() const; | |
| 154 | |
| 155 HeapWord* mem_allocate(size_t size, | |
| 156 bool is_large_noref, | |
| 157 bool is_tlab, | |
| 158 bool* gc_overhead_limit_was_exceeded); | |
| 159 | |
| 160 // We may support a shared contiguous allocation area, if the youngest | |
| 161 // generation does. | |
| 162 bool supports_inline_contig_alloc() const; | |
| 163 HeapWord** top_addr() const; | |
| 164 HeapWord** end_addr() const; | |
| 165 | |
| 166 // Return an estimate of the maximum allocation that could be performed | |
| 167 // without triggering any collection activity. In a generational | |
| 168 // collector, for example, this is probably the largest allocation that | |
| 169 // could be supported in the youngest generation. It is "unsafe" because | |
| 170 // no locks are taken; the result should be treated as an approximation, | |
| 171 // not a guarantee. | |
| 172 size_t unsafe_max_alloc(); | |
| 173 | |
| 174 // Does this heap support heap inspection? (+PrintClassHistogram) | |
| 175 virtual bool supports_heap_inspection() const { return true; } | |
| 176 | |
| 177 // Perform a full collection of the heap; intended for use in implementing | |
| 178 // "System.gc". This implies as full a collection as the CollectedHeap | |
| 179 // supports. Caller does not hold the Heap_lock on entry. | |
| 180 void collect(GCCause::Cause cause); | |
| 181 | |
| 182 // This interface assumes that it's being called by the | |
| 183 // vm thread. It collects the heap assuming that the | |
| 184 // heap lock is already held and that we are executing in | |
| 185 // the context of the vm thread. | |
| 186 void collect_as_vm_thread(GCCause::Cause cause); | |
| 187 | |
| 188 // The same as above but assume that the caller holds the Heap_lock. | |
| 189 void collect_locked(GCCause::Cause cause); | |
| 190 | |
| 191 // Perform a full collection of the first max_level+1 generations. | |
| 192 // Mostly used for testing purposes. Caller does not hold the Heap_lock on entry. | |
| 193 void collect(GCCause::Cause cause, int max_level); | |
| 194 | |
| 195 // Returns "TRUE" iff "p" points into the allocated area of the heap. | |
| 196 // The methods is_in(), is_in_closed_subset() and is_in_youngest() may | |
| 197 // be expensive to compute in general, so, to prevent | |
| 198 // their inadvertent use in product jvm's, we restrict their use to | |
| 199 // assertion checking or verification only. | |
| 200 bool is_in(const void* p) const; | |
| 201 | |
| 202 // override | |
| 203 bool is_in_closed_subset(const void* p) const { | |
| 204 if (UseConcMarkSweepGC) { | |
| 205 return is_in_reserved(p); | |
| 206 } else { | |
| 207 return is_in(p); | |
| 208 } | |
| 209 } | |
| 210 | |
| 211 // Returns "TRUE" iff "p" points into the youngest generation. | |
| 212 bool is_in_youngest(void* p); | |
| 213 | |
| 214 // Iteration functions. | |
| 215 void oop_iterate(OopClosure* cl); | |
| 216 void oop_iterate(MemRegion mr, OopClosure* cl); | |
| 217 void object_iterate(ObjectClosure* cl); | |
| 218 void object_iterate_since_last_GC(ObjectClosure* cl); | |
| 219 Space* space_containing(const void* addr) const; | |
| 220 | |
| 221 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, | |
| 222 // each address in the (reserved) heap is a member of exactly | |
| 223 // one block. The defining characteristic of a block is that it is | |
| 224 // possible to find its size, and thus to progress forward to the next | |
| 225 // block. (Blocks may be of different sizes.) Thus, blocks may | |
| 226 // represent Java objects, or they might be free blocks in a | |
| 227 // free-list-based heap (or subheap), as long as the two kinds are | |
| 228 // distinguishable and the size of each is determinable. | |
| 229 | |
| 230 // Returns the address of the start of the "block" that contains the | |
| 231 // address "addr". We say "blocks" instead of "object" since some heaps | |
| 232 // may not pack objects densely; a chunk may either be an object or a | |
| 233 // non-object. | |
| 234 virtual HeapWord* block_start(const void* addr) const; | |
| 235 | |
| 236 // Requires "addr" to be the start of a chunk, and returns its size. | |
| 237 // "addr + size" is required to be the start of a new chunk, or the end | |
| 238 // of the active area of the heap. Assumes (and verifies in non-product | |
| 239 // builds) that addr is in the allocated part of the heap and is | |
| 240 // the start of a chunk. | |
| 241 virtual size_t block_size(const HeapWord* addr) const; | |
| 242 | |
| 243 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 244 // the block is an object. Assumes (and verifies in non-product | |
| 245 // builds) that addr is in the allocated part of the heap and is | |
| 246 // the start of a chunk. | |
| 247 virtual bool block_is_obj(const HeapWord* addr) const; | |
| 248 | |
| 249 // Section on TLAB's. | |
| 250 virtual bool supports_tlab_allocation() const; | |
| 251 virtual size_t tlab_capacity(Thread* thr) const; | |
| 252 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const; | |
| 253 virtual HeapWord* allocate_new_tlab(size_t size); | |
| 254 | |
| 255 // The "requestor" generation is performing some garbage collection | |
| 256 // action for which it would be useful to have scratch space. The | |
| 257 // requestor promises to allocate no more than "max_alloc_words" in any | |
| 258 // older generation (via promotion say.) Any blocks of space that can | |
| 259 // be provided are returned as a list of ScratchBlocks, sorted by | |
| 260 // decreasing size. | |
| 261 ScratchBlock* gather_scratch(Generation* requestor, size_t max_alloc_words); | |
|
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262 // Allow each generation to reset any scratch space that it has |
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263 // contributed as it needs. |
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264 void release_scratch(); |
| 0 | 265 |
| 266 size_t large_typearray_limit(); | |
| 267 | |
| 268 // Ensure parsability: override | |
| 269 virtual void ensure_parsability(bool retire_tlabs); | |
| 270 | |
| 271 // Time in ms since the longest time a collector ran in | |
| 272 // in any generation. | |
| 273 virtual jlong millis_since_last_gc(); | |
| 274 | |
| 275 // Total number of full collections completed. | |
| 276 unsigned int total_full_collections_completed() { | |
| 277 assert(_full_collections_completed <= _total_full_collections, | |
| 278 "Can't complete more collections than were started"); | |
| 279 return _full_collections_completed; | |
| 280 } | |
| 281 | |
| 282 // Update above counter, as appropriate, at the end of a stop-world GC cycle | |
| 283 unsigned int update_full_collections_completed(); | |
| 284 // Update above counter, as appropriate, at the end of a concurrent GC cycle | |
| 285 unsigned int update_full_collections_completed(unsigned int count); | |
| 286 | |
| 287 // Update "time of last gc" for all constituent generations | |
| 288 // to "now". | |
| 289 void update_time_of_last_gc(jlong now) { | |
| 290 for (int i = 0; i < _n_gens; i++) { | |
| 291 _gens[i]->update_time_of_last_gc(now); | |
| 292 } | |
| 293 perm_gen()->update_time_of_last_gc(now); | |
| 294 } | |
| 295 | |
| 296 // Update the gc statistics for each generation. | |
| 297 // "level" is the level of the lastest collection | |
| 298 void update_gc_stats(int current_level, bool full) { | |
| 299 for (int i = 0; i < _n_gens; i++) { | |
| 300 _gens[i]->update_gc_stats(current_level, full); | |
| 301 } | |
| 302 perm_gen()->update_gc_stats(current_level, full); | |
| 303 } | |
| 304 | |
| 305 // Override. | |
| 306 bool no_gc_in_progress() { return !is_gc_active(); } | |
| 307 | |
| 308 // Override. | |
| 309 void prepare_for_verify(); | |
| 310 | |
| 311 // Override. | |
| 312 void verify(bool allow_dirty, bool silent); | |
| 313 | |
| 314 // Override. | |
| 315 void print() const; | |
| 316 void print_on(outputStream* st) const; | |
| 317 virtual void print_gc_threads_on(outputStream* st) const; | |
| 318 virtual void gc_threads_do(ThreadClosure* tc) const; | |
| 319 virtual void print_tracing_info() const; | |
| 320 | |
| 321 // PrintGC, PrintGCDetails support | |
| 322 void print_heap_change(size_t prev_used) const; | |
| 323 void print_perm_heap_change(size_t perm_prev_used) const; | |
| 324 | |
| 325 // The functions below are helper functions that a subclass of | |
| 326 // "CollectedHeap" can use in the implementation of its virtual | |
| 327 // functions. | |
| 328 | |
| 329 class GenClosure : public StackObj { | |
| 330 public: | |
| 331 virtual void do_generation(Generation* gen) = 0; | |
| 332 }; | |
| 333 | |
| 334 // Apply "cl.do_generation" to all generations in the heap (not including | |
| 335 // the permanent generation). If "old_to_young" determines the order. | |
| 336 void generation_iterate(GenClosure* cl, bool old_to_young); | |
| 337 | |
| 338 void space_iterate(SpaceClosure* cl); | |
| 339 | |
| 340 // Return "true" if all generations (but perm) have reached the | |
| 341 // maximal committed limit that they can reach, without a garbage | |
| 342 // collection. | |
| 343 virtual bool is_maximal_no_gc() const; | |
| 344 | |
| 345 // Return the generation before "gen", or else NULL. | |
| 346 Generation* prev_gen(Generation* gen) const { | |
| 347 int l = gen->level(); | |
| 348 if (l == 0) return NULL; | |
| 349 else return _gens[l-1]; | |
| 350 } | |
| 351 | |
| 352 // Return the generation after "gen", or else NULL. | |
| 353 Generation* next_gen(Generation* gen) const { | |
| 354 int l = gen->level() + 1; | |
| 355 if (l == _n_gens) return NULL; | |
| 356 else return _gens[l]; | |
| 357 } | |
| 358 | |
| 359 Generation* get_gen(int i) const { | |
| 360 if (i >= 0 && i < _n_gens) | |
| 361 return _gens[i]; | |
| 362 else | |
| 363 return NULL; | |
| 364 } | |
| 365 | |
| 366 int n_gens() const { | |
| 367 assert(_n_gens == gen_policy()->number_of_generations(), "Sanity"); | |
| 368 return _n_gens; | |
| 369 } | |
| 370 | |
| 371 // Convenience function to be used in situations where the heap type can be | |
| 372 // asserted to be this type. | |
| 373 static GenCollectedHeap* heap(); | |
| 374 | |
| 375 void set_par_threads(int t); | |
| 376 | |
| 377 | |
| 378 // Invoke the "do_oop" method of one of the closures "not_older_gens" | |
| 379 // or "older_gens" on root locations for the generation at | |
| 380 // "level". (The "older_gens" closure is used for scanning references | |
| 381 // from older generations; "not_older_gens" is used everywhere else.) | |
| 382 // If "younger_gens_as_roots" is false, younger generations are | |
| 383 // not scanned as roots; in this case, the caller must be arranging to | |
| 384 // scan the younger generations itself. (For example, a generation might | |
| 385 // explicitly mark reachable objects in younger generations, to avoid | |
| 386 // excess storage retention.) If "collecting_perm_gen" is false, then | |
| 387 // roots that may only contain references to permGen objects are not | |
| 388 // scanned. The "so" argument determines which of the roots | |
| 389 // the closure is applied to: | |
| 390 // "SO_None" does none; | |
| 391 // "SO_AllClasses" applies the closure to all entries in the SystemDictionary; | |
| 392 // "SO_SystemClasses" to all the "system" classes and loaders; | |
| 393 // "SO_Symbols_and_Strings" applies the closure to all entries in | |
| 394 // SymbolsTable and StringTable. | |
| 395 void gen_process_strong_roots(int level, bool younger_gens_as_roots, | |
| 396 bool collecting_perm_gen, | |
| 397 SharedHeap::ScanningOption so, | |
| 398 OopsInGenClosure* older_gens, | |
| 399 OopsInGenClosure* not_older_gens); | |
| 400 | |
| 401 // Apply "blk" to all the weak roots of the system. These include | |
| 402 // JNI weak roots, the code cache, system dictionary, symbol table, | |
| 403 // string table, and referents of reachable weak refs. | |
| 404 void gen_process_weak_roots(OopClosure* root_closure, | |
| 405 OopClosure* non_root_closure); | |
| 406 | |
| 407 // Set the saved marks of generations, if that makes sense. | |
| 408 // In particular, if any generation might iterate over the oops | |
| 409 // in other generations, it should call this method. | |
| 410 void save_marks(); | |
| 411 | |
| 412 // Apply "cur->do_oop" or "older->do_oop" to all the oops in objects | |
| 413 // allocated since the last call to save_marks in generations at or above | |
| 414 // "level" (including the permanent generation.) The "cur" closure is | |
| 415 // applied to references in the generation at "level", and the "older" | |
| 416 // closure to older (and permanent) generations. | |
| 417 #define GCH_SINCE_SAVE_MARKS_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
| 418 void oop_since_save_marks_iterate(int level, \ | |
| 419 OopClosureType* cur, \ | |
| 420 OopClosureType* older); | |
| 421 | |
| 422 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DECL) | |
| 423 | |
| 424 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DECL | |
| 425 | |
| 426 // Returns "true" iff no allocations have occurred in any generation at | |
| 427 // "level" or above (including the permanent generation) since the last | |
| 428 // call to "save_marks". | |
| 429 bool no_allocs_since_save_marks(int level); | |
| 430 | |
| 431 // If a generation bails out of an incremental collection, | |
| 432 // it sets this flag. | |
| 433 bool incremental_collection_will_fail() { | |
| 434 return _incremental_collection_will_fail; | |
| 435 } | |
| 436 void set_incremental_collection_will_fail() { | |
| 437 _incremental_collection_will_fail = true; | |
| 438 } | |
| 439 void clear_incremental_collection_will_fail() { | |
| 440 _incremental_collection_will_fail = false; | |
| 441 } | |
| 442 | |
| 443 bool last_incremental_collection_failed() const { | |
| 444 return _last_incremental_collection_failed; | |
| 445 } | |
| 446 void set_last_incremental_collection_failed() { | |
| 447 _last_incremental_collection_failed = true; | |
| 448 } | |
| 449 void clear_last_incremental_collection_failed() { | |
| 450 _last_incremental_collection_failed = false; | |
| 451 } | |
| 452 | |
| 453 // Promotion of obj into gen failed. Try to promote obj to higher non-perm | |
| 454 // gens in ascending order; return the new location of obj if successful. | |
| 455 // Otherwise, try expand-and-allocate for obj in each generation starting at | |
| 456 // gen; return the new location of obj if successful. Otherwise, return NULL. | |
| 457 oop handle_failed_promotion(Generation* gen, | |
| 458 oop obj, | |
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459 size_t obj_size); |
| 0 | 460 |
| 461 private: | |
| 462 // Accessor for memory state verification support | |
| 463 NOT_PRODUCT( | |
| 464 static size_t skip_header_HeapWords() { return _skip_header_HeapWords; } | |
| 465 ) | |
| 466 | |
| 467 // Override | |
| 468 void check_for_non_bad_heap_word_value(HeapWord* addr, | |
| 469 size_t size) PRODUCT_RETURN; | |
| 470 | |
| 471 // For use by mark-sweep. As implemented, mark-sweep-compact is global | |
| 472 // in an essential way: compaction is performed across generations, by | |
| 473 // iterating over spaces. | |
| 474 void prepare_for_compaction(); | |
| 475 | |
| 476 // Perform a full collection of the first max_level+1 generations. | |
| 477 // This is the low level interface used by the public versions of | |
| 478 // collect() and collect_locked(). Caller holds the Heap_lock on entry. | |
| 479 void collect_locked(GCCause::Cause cause, int max_level); | |
| 480 | |
| 481 // Returns success or failure. | |
| 482 bool create_cms_collector(); | |
| 483 | |
| 484 // In support of ExplicitGCInvokesConcurrent functionality | |
| 485 bool should_do_concurrent_full_gc(GCCause::Cause cause); | |
| 486 void collect_mostly_concurrent(GCCause::Cause cause); | |
| 487 | |
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488 // Save the tops of the spaces in all generations |
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489 void record_gen_tops_before_GC() PRODUCT_RETURN; |
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490 |
| 0 | 491 protected: |
| 492 virtual void gc_prologue(bool full); | |
| 493 virtual void gc_epilogue(bool full); | |
| 494 | |
| 495 public: | |
| 496 virtual void preload_and_dump(TRAPS) KERNEL_RETURN; | |
| 497 }; |