Mercurial > hg > truffle
annotate src/share/vm/memory/genMarkSweep.cpp @ 263:12eea04c8b06
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
Summary: Maintain a high water mark for the allocations in a space and mangle only up to that high water mark.
Reviewed-by: ysr, apetrusenko
| author | jmasa |
|---|---|
| date | Wed, 09 Jul 2008 15:08:55 -0700 |
| parents | ba764ed4b6f2 |
| children | 850fdf70db2b |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 2001-2007 Sun Microsystems, Inc. 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 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 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_genMarkSweep.cpp.incl" | |
| 27 | |
| 28 void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, | |
| 29 bool clear_all_softrefs) { | |
| 30 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
| 31 | |
| 32 // hook up weak ref data so it can be used during Mark-Sweep | |
| 33 assert(ref_processor() == NULL, "no stomping"); | |
| 34 _ref_processor = rp; | |
| 35 assert(rp != NULL, "should be non-NULL"); | |
| 36 | |
| 37 TraceTime t1("Full GC", PrintGC && !PrintGCDetails, true, gclog_or_tty); | |
| 38 | |
| 39 // When collecting the permanent generation methodOops may be moving, | |
| 40 // so we either have to flush all bcp data or convert it into bci. | |
| 41 CodeCache::gc_prologue(); | |
| 42 Threads::gc_prologue(); | |
| 43 | |
| 44 // Increment the invocation count for the permanent generation, since it is | |
| 45 // implicitly collected whenever we do a full mark sweep collection. | |
| 46 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 47 gch->perm_gen()->stat_record()->invocations++; | |
| 48 | |
| 49 // Capture heap size before collection for printing. | |
| 50 size_t gch_prev_used = gch->used(); | |
| 51 | |
| 52 // Some of the card table updates below assume that the perm gen is | |
| 53 // also being collected. | |
| 54 assert(level == gch->n_gens() - 1, | |
| 55 "All generations are being collected, ergo perm gen too."); | |
| 56 | |
| 57 // Capture used regions for each generation that will be | |
| 58 // subject to collection, so that card table adjustments can | |
| 59 // be made intelligently (see clear / invalidate further below). | |
| 60 gch->save_used_regions(level, true /* perm */); | |
| 61 | |
| 62 allocate_stacks(); | |
| 63 | |
| 64 mark_sweep_phase1(level, clear_all_softrefs); | |
| 65 | |
| 66 mark_sweep_phase2(); | |
| 67 | |
| 68 // Don't add any more derived pointers during phase3 | |
| 69 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
| 70 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
| 71 | |
| 72 mark_sweep_phase3(level); | |
| 73 | |
| 74 VALIDATE_MARK_SWEEP_ONLY( | |
| 75 if (ValidateMarkSweep) { | |
|
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76 guarantee(_root_refs_stack->length() == 0, "should be empty by now"); |
| 0 | 77 } |
| 78 ) | |
| 79 | |
| 80 mark_sweep_phase4(); | |
| 81 | |
| 82 VALIDATE_MARK_SWEEP_ONLY( | |
| 83 if (ValidateMarkSweep) { | |
| 84 guarantee(_live_oops->length() == _live_oops_moved_to->length(), | |
| 85 "should be the same size"); | |
| 86 } | |
| 87 ) | |
| 88 | |
| 89 restore_marks(); | |
| 90 | |
| 91 // Set saved marks for allocation profiler (and other things? -- dld) | |
| 92 // (Should this be in general part?) | |
| 93 gch->save_marks(); | |
| 94 | |
| 95 deallocate_stacks(); | |
| 96 | |
| 97 // If compaction completely evacuated all generations younger than this | |
| 98 // one, then we can clear the card table. Otherwise, we must invalidate | |
| 99 // it (consider all cards dirty). In the future, we might consider doing | |
| 100 // compaction within generations only, and doing card-table sliding. | |
| 101 bool all_empty = true; | |
| 102 for (int i = 0; all_empty && i < level; i++) { | |
| 103 Generation* g = gch->get_gen(i); | |
| 104 all_empty = all_empty && gch->get_gen(i)->used() == 0; | |
| 105 } | |
| 106 GenRemSet* rs = gch->rem_set(); | |
| 107 // Clear/invalidate below make use of the "prev_used_regions" saved earlier. | |
| 108 if (all_empty) { | |
| 109 // We've evacuated all generations below us. | |
| 110 Generation* g = gch->get_gen(level); | |
| 111 rs->clear_into_younger(g, true /* perm */); | |
| 112 } else { | |
| 113 // Invalidate the cards corresponding to the currently used | |
| 114 // region and clear those corresponding to the evacuated region | |
| 115 // of all generations just collected (i.e. level and younger). | |
| 116 rs->invalidate_or_clear(gch->get_gen(level), | |
| 117 true /* younger */, | |
| 118 true /* perm */); | |
| 119 } | |
| 120 | |
| 121 Threads::gc_epilogue(); | |
| 122 CodeCache::gc_epilogue(); | |
| 123 | |
| 124 if (PrintGC && !PrintGCDetails) { | |
| 125 gch->print_heap_change(gch_prev_used); | |
| 126 } | |
| 127 | |
| 128 // refs processing: clean slate | |
| 129 _ref_processor = NULL; | |
| 130 | |
| 131 // Update heap occupancy information which is used as | |
| 132 // input to soft ref clearing policy at the next gc. | |
| 133 Universe::update_heap_info_at_gc(); | |
| 134 | |
| 135 // Update time of last gc for all generations we collected | |
| 136 // (which curently is all the generations in the heap). | |
| 137 gch->update_time_of_last_gc(os::javaTimeMillis()); | |
| 138 } | |
| 139 | |
| 140 void GenMarkSweep::allocate_stacks() { | |
| 141 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 142 // Scratch request on behalf of oldest generation; will do no | |
| 143 // allocation. | |
| 144 ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0); | |
| 145 | |
| 146 // $$$ To cut a corner, we'll only use the first scratch block, and then | |
| 147 // revert to malloc. | |
| 148 if (scratch != NULL) { | |
| 149 _preserved_count_max = | |
| 150 scratch->num_words * HeapWordSize / sizeof(PreservedMark); | |
| 151 } else { | |
| 152 _preserved_count_max = 0; | |
| 153 } | |
| 154 | |
| 155 _preserved_marks = (PreservedMark*)scratch; | |
| 156 _preserved_count = 0; | |
| 157 _preserved_mark_stack = NULL; | |
| 158 _preserved_oop_stack = NULL; | |
| 159 | |
| 160 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
| 161 | |
| 162 int size = SystemDictionary::number_of_classes() * 2; | |
| 163 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); | |
| 164 | |
| 165 #ifdef VALIDATE_MARK_SWEEP | |
| 166 if (ValidateMarkSweep) { | |
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167 _root_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
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coleenp
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168 _other_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
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ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
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diff
changeset
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169 _adjusted_pointers = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
| 0 | 170 _live_oops = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); |
| 171 _live_oops_moved_to = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); | |
| 172 _live_oops_size = new (ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 173 } | |
| 174 if (RecordMarkSweepCompaction) { | |
| 175 if (_cur_gc_live_oops == NULL) { | |
| 176 _cur_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 177 _cur_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 178 _cur_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 179 _last_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 180 _last_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 181 _last_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 182 } else { | |
| 183 _cur_gc_live_oops->clear(); | |
| 184 _cur_gc_live_oops_moved_to->clear(); | |
| 185 _cur_gc_live_oops_size->clear(); | |
| 186 } | |
| 187 } | |
| 188 #endif | |
| 189 } | |
| 190 | |
| 191 | |
| 192 void GenMarkSweep::deallocate_stacks() { | |
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193 |
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194 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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195 gch->release_scratch(); |
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196 |
| 0 | 197 if (_preserved_oop_stack) { |
| 198 delete _preserved_mark_stack; | |
| 199 _preserved_mark_stack = NULL; | |
| 200 delete _preserved_oop_stack; | |
| 201 _preserved_oop_stack = NULL; | |
| 202 } | |
| 203 | |
| 204 delete _marking_stack; | |
| 205 delete _revisit_klass_stack; | |
| 206 | |
| 207 #ifdef VALIDATE_MARK_SWEEP | |
| 208 if (ValidateMarkSweep) { | |
| 209 delete _root_refs_stack; | |
| 210 delete _other_refs_stack; | |
| 211 delete _adjusted_pointers; | |
| 212 delete _live_oops; | |
| 213 delete _live_oops_size; | |
| 214 delete _live_oops_moved_to; | |
| 215 _live_oops_index = 0; | |
| 216 _live_oops_index_at_perm = 0; | |
| 217 } | |
| 218 #endif | |
| 219 } | |
| 220 | |
| 221 void GenMarkSweep::mark_sweep_phase1(int level, | |
| 222 bool clear_all_softrefs) { | |
| 223 // Recursively traverse all live objects and mark them | |
| 224 EventMark m("1 mark object"); | |
| 225 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); | |
| 226 trace(" 1"); | |
| 227 | |
| 228 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 229 | |
| 230 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 231 | |
| 232 // Because follow_root_closure is created statically, cannot | |
| 233 // use OopsInGenClosure constructor which takes a generation, | |
| 234 // as the Universe has not been created when the static constructors | |
| 235 // are run. | |
| 236 follow_root_closure.set_orig_generation(gch->get_gen(level)); | |
| 237 | |
| 238 gch->gen_process_strong_roots(level, | |
| 239 false, // Younger gens are not roots. | |
| 240 true, // Collecting permanent generation. | |
| 241 SharedHeap::SO_SystemClasses, | |
| 242 &follow_root_closure, &follow_root_closure); | |
| 243 | |
| 244 // Process reference objects found during marking | |
| 245 { | |
| 246 ReferencePolicy *soft_ref_policy; | |
| 247 if (clear_all_softrefs) { | |
| 248 soft_ref_policy = new AlwaysClearPolicy(); | |
| 249 } else { | |
| 250 #ifdef COMPILER2 | |
| 251 soft_ref_policy = new LRUMaxHeapPolicy(); | |
| 252 #else | |
| 253 soft_ref_policy = new LRUCurrentHeapPolicy(); | |
| 254 #endif // COMPILER2 | |
| 255 } | |
| 256 assert(soft_ref_policy != NULL,"No soft reference policy"); | |
| 257 ref_processor()->process_discovered_references( | |
| 258 soft_ref_policy, &is_alive, &keep_alive, | |
| 259 &follow_stack_closure, NULL); | |
| 260 } | |
| 261 | |
| 262 // Follow system dictionary roots and unload classes | |
| 263 bool purged_class = SystemDictionary::do_unloading(&is_alive); | |
| 264 | |
| 265 // Follow code cache roots | |
| 266 CodeCache::do_unloading(&is_alive, &keep_alive, purged_class); | |
| 267 follow_stack(); // Flush marking stack | |
| 268 | |
| 269 // Update subklass/sibling/implementor links of live klasses | |
| 270 follow_weak_klass_links(); | |
| 271 assert(_marking_stack->is_empty(), "just drained"); | |
| 272 | |
| 273 // Visit symbol and interned string tables and delete unmarked oops | |
| 274 SymbolTable::unlink(&is_alive); | |
| 275 StringTable::unlink(&is_alive); | |
| 276 | |
| 277 assert(_marking_stack->is_empty(), "stack should be empty by now"); | |
| 278 } | |
| 279 | |
| 280 | |
| 281 void GenMarkSweep::mark_sweep_phase2() { | |
| 282 // Now all live objects are marked, compute the new object addresses. | |
| 283 | |
| 284 // It is imperative that we traverse perm_gen LAST. If dead space is | |
| 285 // allowed a range of dead object may get overwritten by a dead int | |
| 286 // array. If perm_gen is not traversed last a klassOop may get | |
| 287 // overwritten. This is fine since it is dead, but if the class has dead | |
| 288 // instances we have to skip them, and in order to find their size we | |
| 289 // need the klassOop! | |
| 290 // | |
| 291 // It is not required that we traverse spaces in the same order in | |
| 292 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
| 293 // tracking expects us to do so. See comment under phase4. | |
| 294 | |
| 295 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 296 Generation* pg = gch->perm_gen(); | |
| 297 | |
| 298 EventMark m("2 compute new addresses"); | |
| 299 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); | |
| 300 trace("2"); | |
| 301 | |
| 302 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 303 | |
| 304 gch->prepare_for_compaction(); | |
| 305 | |
| 306 VALIDATE_MARK_SWEEP_ONLY(_live_oops_index_at_perm = _live_oops_index); | |
| 307 CompactPoint perm_cp(pg, NULL, NULL); | |
| 308 pg->prepare_for_compaction(&perm_cp); | |
| 309 } | |
| 310 | |
| 311 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure { | |
| 312 public: | |
| 313 void do_generation(Generation* gen) { | |
| 314 gen->adjust_pointers(); | |
| 315 } | |
| 316 }; | |
| 317 | |
| 318 void GenMarkSweep::mark_sweep_phase3(int level) { | |
| 319 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 320 Generation* pg = gch->perm_gen(); | |
| 321 | |
| 322 // Adjust the pointers to reflect the new locations | |
| 323 EventMark m("3 adjust pointers"); | |
| 324 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); | |
| 325 trace("3"); | |
| 326 | |
| 327 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 328 | |
| 329 // Needs to be done before the system dictionary is adjusted. | |
| 330 pg->pre_adjust_pointers(); | |
| 331 | |
| 332 // Because the two closures below are created statically, cannot | |
| 333 // use OopsInGenClosure constructor which takes a generation, | |
| 334 // as the Universe has not been created when the static constructors | |
| 335 // are run. | |
| 336 adjust_root_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
| 337 adjust_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
| 338 | |
| 339 gch->gen_process_strong_roots(level, | |
| 340 false, // Younger gens are not roots. | |
| 341 true, // Collecting permanent generation. | |
| 342 SharedHeap::SO_AllClasses, | |
| 343 &adjust_root_pointer_closure, | |
| 344 &adjust_root_pointer_closure); | |
| 345 | |
| 346 // Now adjust pointers in remaining weak roots. (All of which should | |
| 347 // have been cleared if they pointed to non-surviving objects.) | |
| 348 gch->gen_process_weak_roots(&adjust_root_pointer_closure, | |
| 349 &adjust_pointer_closure); | |
| 350 | |
| 351 adjust_marks(); | |
| 352 GenAdjustPointersClosure blk; | |
| 353 gch->generation_iterate(&blk, true); | |
| 354 pg->adjust_pointers(); | |
| 355 } | |
| 356 | |
| 357 class GenCompactClosure: public GenCollectedHeap::GenClosure { | |
| 358 public: | |
| 359 void do_generation(Generation* gen) { | |
| 360 gen->compact(); | |
| 361 } | |
| 362 }; | |
| 363 | |
| 364 void GenMarkSweep::mark_sweep_phase4() { | |
| 365 // All pointers are now adjusted, move objects accordingly | |
| 366 | |
| 367 // It is imperative that we traverse perm_gen first in phase4. All | |
| 368 // classes must be allocated earlier than their instances, and traversing | |
| 369 // perm_gen first makes sure that all klassOops have moved to their new | |
| 370 // location before any instance does a dispatch through it's klass! | |
| 371 | |
| 372 // The ValidateMarkSweep live oops tracking expects us to traverse spaces | |
| 373 // in the same order in phase2, phase3 and phase4. We don't quite do that | |
| 374 // here (perm_gen first rather than last), so we tell the validate code | |
| 375 // to use a higher index (saved from phase2) when verifying perm_gen. | |
| 376 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 377 Generation* pg = gch->perm_gen(); | |
| 378 | |
| 379 EventMark m("4 compact heap"); | |
| 380 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); | |
| 381 trace("4"); | |
| 382 | |
| 383 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(true)); | |
| 384 | |
| 385 pg->compact(); | |
| 386 | |
| 387 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 388 | |
| 389 GenCompactClosure blk; | |
| 390 gch->generation_iterate(&blk, true); | |
| 391 | |
| 392 VALIDATE_MARK_SWEEP_ONLY(compaction_complete()); | |
| 393 | |
| 394 pg->post_compact(); // Shared spaces verification. | |
| 395 } |