Mercurial > hg > truffle
annotate src/share/vm/memory/genMarkSweep.cpp @ 2177:3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
| author | coleenp |
|---|---|
| date | Thu, 27 Jan 2011 16:11:27 -0800 |
| parents | 9afee0b9fc1d |
| children | 1d1603768966 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "classfile/javaClasses.hpp" | |
| 27 #include "classfile/symbolTable.hpp" | |
| 28 #include "classfile/systemDictionary.hpp" | |
| 29 #include "classfile/vmSymbols.hpp" | |
| 30 #include "code/codeCache.hpp" | |
| 31 #include "code/icBuffer.hpp" | |
| 32 #include "gc_interface/collectedHeap.inline.hpp" | |
| 33 #include "memory/genCollectedHeap.hpp" | |
| 34 #include "memory/genMarkSweep.hpp" | |
| 35 #include "memory/genOopClosures.inline.hpp" | |
| 36 #include "memory/generation.inline.hpp" | |
| 37 #include "memory/modRefBarrierSet.hpp" | |
| 38 #include "memory/referencePolicy.hpp" | |
| 39 #include "memory/space.hpp" | |
| 40 #include "oops/instanceRefKlass.hpp" | |
| 41 #include "oops/oop.inline.hpp" | |
| 42 #include "prims/jvmtiExport.hpp" | |
| 43 #include "runtime/fprofiler.hpp" | |
| 44 #include "runtime/handles.inline.hpp" | |
| 45 #include "runtime/synchronizer.hpp" | |
| 46 #include "runtime/vmThread.hpp" | |
| 47 #include "utilities/copy.hpp" | |
| 48 #include "utilities/events.hpp" | |
| 49 #ifdef TARGET_OS_FAMILY_linux | |
| 50 # include "thread_linux.inline.hpp" | |
| 51 #endif | |
| 52 #ifdef TARGET_OS_FAMILY_solaris | |
| 53 # include "thread_solaris.inline.hpp" | |
| 54 #endif | |
| 55 #ifdef TARGET_OS_FAMILY_windows | |
| 56 # include "thread_windows.inline.hpp" | |
| 57 #endif | |
| 0 | 58 |
| 59 void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, | |
| 60 bool clear_all_softrefs) { | |
| 61 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
| 62 | |
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63 GenCollectedHeap* gch = GenCollectedHeap::heap(); |
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64 #ifdef ASSERT |
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65 if (gch->collector_policy()->should_clear_all_soft_refs()) { |
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66 assert(clear_all_softrefs, "Policy should have been checked earlier"); |
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67 } |
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68 #endif |
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69 |
| 0 | 70 // hook up weak ref data so it can be used during Mark-Sweep |
| 71 assert(ref_processor() == NULL, "no stomping"); | |
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72 assert(rp != NULL, "should be non-NULL"); |
| 0 | 73 _ref_processor = rp; |
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74 rp->setup_policy(clear_all_softrefs); |
| 0 | 75 |
| 76 TraceTime t1("Full GC", PrintGC && !PrintGCDetails, true, gclog_or_tty); | |
| 77 | |
| 78 // When collecting the permanent generation methodOops may be moving, | |
| 79 // so we either have to flush all bcp data or convert it into bci. | |
| 80 CodeCache::gc_prologue(); | |
| 81 Threads::gc_prologue(); | |
| 82 | |
| 83 // Increment the invocation count for the permanent generation, since it is | |
| 84 // implicitly collected whenever we do a full mark sweep collection. | |
| 85 gch->perm_gen()->stat_record()->invocations++; | |
| 86 | |
| 87 // Capture heap size before collection for printing. | |
| 88 size_t gch_prev_used = gch->used(); | |
| 89 | |
| 90 // Some of the card table updates below assume that the perm gen is | |
| 91 // also being collected. | |
| 92 assert(level == gch->n_gens() - 1, | |
| 93 "All generations are being collected, ergo perm gen too."); | |
| 94 | |
| 95 // Capture used regions for each generation that will be | |
| 96 // subject to collection, so that card table adjustments can | |
| 97 // be made intelligently (see clear / invalidate further below). | |
| 98 gch->save_used_regions(level, true /* perm */); | |
| 99 | |
| 100 allocate_stacks(); | |
| 101 | |
| 102 mark_sweep_phase1(level, clear_all_softrefs); | |
| 103 | |
| 104 mark_sweep_phase2(); | |
| 105 | |
| 106 // Don't add any more derived pointers during phase3 | |
| 107 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
| 108 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
| 109 | |
| 110 mark_sweep_phase3(level); | |
| 111 | |
| 112 VALIDATE_MARK_SWEEP_ONLY( | |
| 113 if (ValidateMarkSweep) { | |
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114 guarantee(_root_refs_stack->length() == 0, "should be empty by now"); |
| 0 | 115 } |
| 116 ) | |
| 117 | |
| 118 mark_sweep_phase4(); | |
| 119 | |
| 120 VALIDATE_MARK_SWEEP_ONLY( | |
| 121 if (ValidateMarkSweep) { | |
| 122 guarantee(_live_oops->length() == _live_oops_moved_to->length(), | |
| 123 "should be the same size"); | |
| 124 } | |
| 125 ) | |
| 126 | |
| 127 restore_marks(); | |
| 128 | |
| 129 // Set saved marks for allocation profiler (and other things? -- dld) | |
| 130 // (Should this be in general part?) | |
| 131 gch->save_marks(); | |
| 132 | |
| 133 deallocate_stacks(); | |
| 134 | |
| 135 // If compaction completely evacuated all generations younger than this | |
| 136 // one, then we can clear the card table. Otherwise, we must invalidate | |
| 137 // it (consider all cards dirty). In the future, we might consider doing | |
| 138 // compaction within generations only, and doing card-table sliding. | |
| 139 bool all_empty = true; | |
| 140 for (int i = 0; all_empty && i < level; i++) { | |
| 141 Generation* g = gch->get_gen(i); | |
| 142 all_empty = all_empty && gch->get_gen(i)->used() == 0; | |
| 143 } | |
| 144 GenRemSet* rs = gch->rem_set(); | |
| 145 // Clear/invalidate below make use of the "prev_used_regions" saved earlier. | |
| 146 if (all_empty) { | |
| 147 // We've evacuated all generations below us. | |
| 148 Generation* g = gch->get_gen(level); | |
| 149 rs->clear_into_younger(g, true /* perm */); | |
| 150 } else { | |
| 151 // Invalidate the cards corresponding to the currently used | |
| 152 // region and clear those corresponding to the evacuated region | |
| 153 // of all generations just collected (i.e. level and younger). | |
| 154 rs->invalidate_or_clear(gch->get_gen(level), | |
| 155 true /* younger */, | |
| 156 true /* perm */); | |
| 157 } | |
| 158 | |
| 159 Threads::gc_epilogue(); | |
| 160 CodeCache::gc_epilogue(); | |
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161 JvmtiExport::gc_epilogue(); |
| 0 | 162 |
| 163 if (PrintGC && !PrintGCDetails) { | |
| 164 gch->print_heap_change(gch_prev_used); | |
| 165 } | |
| 166 | |
| 167 // refs processing: clean slate | |
| 168 _ref_processor = NULL; | |
| 169 | |
| 170 // Update heap occupancy information which is used as | |
| 171 // input to soft ref clearing policy at the next gc. | |
| 172 Universe::update_heap_info_at_gc(); | |
| 173 | |
| 174 // Update time of last gc for all generations we collected | |
| 175 // (which curently is all the generations in the heap). | |
| 176 gch->update_time_of_last_gc(os::javaTimeMillis()); | |
| 177 } | |
| 178 | |
| 179 void GenMarkSweep::allocate_stacks() { | |
| 180 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 181 // Scratch request on behalf of oldest generation; will do no | |
| 182 // allocation. | |
| 183 ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0); | |
| 184 | |
| 185 // $$$ To cut a corner, we'll only use the first scratch block, and then | |
| 186 // revert to malloc. | |
| 187 if (scratch != NULL) { | |
| 188 _preserved_count_max = | |
| 189 scratch->num_words * HeapWordSize / sizeof(PreservedMark); | |
| 190 } else { | |
| 191 _preserved_count_max = 0; | |
| 192 } | |
| 193 | |
| 194 _preserved_marks = (PreservedMark*)scratch; | |
| 195 _preserved_count = 0; | |
| 196 | |
| 197 #ifdef VALIDATE_MARK_SWEEP | |
| 198 if (ValidateMarkSweep) { | |
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199 _root_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
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200 _other_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
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201 _adjusted_pointers = new (ResourceObj::C_HEAP) GrowableArray<void*>(100, true); |
| 0 | 202 _live_oops = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); |
| 203 _live_oops_moved_to = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); | |
| 204 _live_oops_size = new (ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 205 } | |
| 206 if (RecordMarkSweepCompaction) { | |
| 207 if (_cur_gc_live_oops == NULL) { | |
| 208 _cur_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 209 _cur_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 210 _cur_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 211 _last_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 212 _last_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
| 213 _last_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
| 214 } else { | |
| 215 _cur_gc_live_oops->clear(); | |
| 216 _cur_gc_live_oops_moved_to->clear(); | |
| 217 _cur_gc_live_oops_size->clear(); | |
| 218 } | |
| 219 } | |
| 220 #endif | |
| 221 } | |
| 222 | |
| 223 | |
| 224 void GenMarkSweep::deallocate_stacks() { | |
| 356 | 225 if (!UseG1GC) { |
| 226 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 227 gch->release_scratch(); | |
| 228 } | |
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229 |
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230 _preserved_mark_stack.clear(true); |
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231 _preserved_oop_stack.clear(true); |
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232 _marking_stack.clear(); |
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233 _objarray_stack.clear(true); |
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234 _revisit_klass_stack.clear(true); |
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235 _revisit_mdo_stack.clear(true); |
| 0 | 236 |
| 237 #ifdef VALIDATE_MARK_SWEEP | |
| 238 if (ValidateMarkSweep) { | |
| 239 delete _root_refs_stack; | |
| 240 delete _other_refs_stack; | |
| 241 delete _adjusted_pointers; | |
| 242 delete _live_oops; | |
| 243 delete _live_oops_size; | |
| 244 delete _live_oops_moved_to; | |
| 245 _live_oops_index = 0; | |
| 246 _live_oops_index_at_perm = 0; | |
| 247 } | |
| 248 #endif | |
| 249 } | |
| 250 | |
| 251 void GenMarkSweep::mark_sweep_phase1(int level, | |
| 252 bool clear_all_softrefs) { | |
| 253 // Recursively traverse all live objects and mark them | |
| 254 EventMark m("1 mark object"); | |
| 255 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); | |
| 256 trace(" 1"); | |
| 257 | |
| 258 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 259 | |
| 260 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 261 | |
| 262 // Because follow_root_closure is created statically, cannot | |
| 263 // use OopsInGenClosure constructor which takes a generation, | |
| 264 // as the Universe has not been created when the static constructors | |
| 265 // are run. | |
| 266 follow_root_closure.set_orig_generation(gch->get_gen(level)); | |
| 267 | |
| 268 gch->gen_process_strong_roots(level, | |
| 269 false, // Younger gens are not roots. | |
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270 true, // activate StrongRootsScope |
| 0 | 271 true, // Collecting permanent generation. |
| 272 SharedHeap::SO_SystemClasses, | |
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273 &follow_root_closure, |
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274 true, // walk code active on stacks |
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275 &follow_root_closure); |
| 0 | 276 |
| 277 // Process reference objects found during marking | |
| 278 { | |
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279 ref_processor()->setup_policy(clear_all_softrefs); |
| 0 | 280 ref_processor()->process_discovered_references( |
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281 &is_alive, &keep_alive, &follow_stack_closure, NULL); |
| 0 | 282 } |
| 283 | |
| 284 // Follow system dictionary roots and unload classes | |
| 285 bool purged_class = SystemDictionary::do_unloading(&is_alive); | |
| 286 | |
| 287 // Follow code cache roots | |
| 288 CodeCache::do_unloading(&is_alive, &keep_alive, purged_class); | |
| 289 follow_stack(); // Flush marking stack | |
| 290 | |
| 291 // Update subklass/sibling/implementor links of live klasses | |
| 292 follow_weak_klass_links(); | |
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293 assert(_marking_stack.is_empty(), "just drained"); |
| 0 | 294 |
| 941 | 295 // Visit memoized MDO's and clear any unmarked weak refs |
| 296 follow_mdo_weak_refs(); | |
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297 assert(_marking_stack.is_empty(), "just drained"); |
| 941 | 298 |
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299 // Visit interned string tables and delete unmarked oops |
| 0 | 300 StringTable::unlink(&is_alive); |
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301 // Clean up unreferenced symbols in symbol table. |
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302 SymbolTable::unlink(); |
| 0 | 303 |
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304 assert(_marking_stack.is_empty(), "stack should be empty by now"); |
| 0 | 305 } |
| 306 | |
| 307 | |
| 308 void GenMarkSweep::mark_sweep_phase2() { | |
| 309 // Now all live objects are marked, compute the new object addresses. | |
| 310 | |
| 311 // It is imperative that we traverse perm_gen LAST. If dead space is | |
| 312 // allowed a range of dead object may get overwritten by a dead int | |
| 313 // array. If perm_gen is not traversed last a klassOop may get | |
| 314 // overwritten. This is fine since it is dead, but if the class has dead | |
| 315 // instances we have to skip them, and in order to find their size we | |
| 316 // need the klassOop! | |
| 317 // | |
| 318 // It is not required that we traverse spaces in the same order in | |
| 319 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
| 320 // tracking expects us to do so. See comment under phase4. | |
| 321 | |
| 322 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 323 Generation* pg = gch->perm_gen(); | |
| 324 | |
| 325 EventMark m("2 compute new addresses"); | |
| 326 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); | |
| 327 trace("2"); | |
| 328 | |
| 329 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 330 | |
| 331 gch->prepare_for_compaction(); | |
| 332 | |
| 333 VALIDATE_MARK_SWEEP_ONLY(_live_oops_index_at_perm = _live_oops_index); | |
| 334 CompactPoint perm_cp(pg, NULL, NULL); | |
| 335 pg->prepare_for_compaction(&perm_cp); | |
| 336 } | |
| 337 | |
| 338 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure { | |
| 339 public: | |
| 340 void do_generation(Generation* gen) { | |
| 341 gen->adjust_pointers(); | |
| 342 } | |
| 343 }; | |
| 344 | |
| 345 void GenMarkSweep::mark_sweep_phase3(int level) { | |
| 346 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 347 Generation* pg = gch->perm_gen(); | |
| 348 | |
| 349 // Adjust the pointers to reflect the new locations | |
| 350 EventMark m("3 adjust pointers"); | |
| 351 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); | |
| 352 trace("3"); | |
| 353 | |
| 354 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 355 | |
| 356 // Needs to be done before the system dictionary is adjusted. | |
| 357 pg->pre_adjust_pointers(); | |
| 358 | |
| 359 // Because the two closures below are created statically, cannot | |
| 360 // use OopsInGenClosure constructor which takes a generation, | |
| 361 // as the Universe has not been created when the static constructors | |
| 362 // are run. | |
| 363 adjust_root_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
| 364 adjust_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
| 365 | |
| 366 gch->gen_process_strong_roots(level, | |
| 367 false, // Younger gens are not roots. | |
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368 true, // activate StrongRootsScope |
| 0 | 369 true, // Collecting permanent generation. |
| 370 SharedHeap::SO_AllClasses, | |
| 371 &adjust_root_pointer_closure, | |
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372 false, // do not walk code |
| 0 | 373 &adjust_root_pointer_closure); |
| 374 | |
| 375 // Now adjust pointers in remaining weak roots. (All of which should | |
| 376 // have been cleared if they pointed to non-surviving objects.) | |
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377 CodeBlobToOopClosure adjust_code_pointer_closure(&adjust_pointer_closure, |
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378 /*do_marking=*/ false); |
| 0 | 379 gch->gen_process_weak_roots(&adjust_root_pointer_closure, |
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380 &adjust_code_pointer_closure, |
| 0 | 381 &adjust_pointer_closure); |
| 382 | |
| 383 adjust_marks(); | |
| 384 GenAdjustPointersClosure blk; | |
| 385 gch->generation_iterate(&blk, true); | |
| 386 pg->adjust_pointers(); | |
| 387 } | |
| 388 | |
| 389 class GenCompactClosure: public GenCollectedHeap::GenClosure { | |
| 390 public: | |
| 391 void do_generation(Generation* gen) { | |
| 392 gen->compact(); | |
| 393 } | |
| 394 }; | |
| 395 | |
| 396 void GenMarkSweep::mark_sweep_phase4() { | |
| 397 // All pointers are now adjusted, move objects accordingly | |
| 398 | |
| 399 // It is imperative that we traverse perm_gen first in phase4. All | |
| 400 // classes must be allocated earlier than their instances, and traversing | |
| 401 // perm_gen first makes sure that all klassOops have moved to their new | |
| 402 // location before any instance does a dispatch through it's klass! | |
| 403 | |
| 404 // The ValidateMarkSweep live oops tracking expects us to traverse spaces | |
| 405 // in the same order in phase2, phase3 and phase4. We don't quite do that | |
| 406 // here (perm_gen first rather than last), so we tell the validate code | |
| 407 // to use a higher index (saved from phase2) when verifying perm_gen. | |
| 408 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
| 409 Generation* pg = gch->perm_gen(); | |
| 410 | |
| 411 EventMark m("4 compact heap"); | |
| 412 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); | |
| 413 trace("4"); | |
| 414 | |
| 415 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(true)); | |
| 416 | |
| 417 pg->compact(); | |
| 418 | |
| 419 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
| 420 | |
| 421 GenCompactClosure blk; | |
| 422 gch->generation_iterate(&blk, true); | |
| 423 | |
| 424 VALIDATE_MARK_SWEEP_ONLY(compaction_complete()); | |
| 425 | |
| 426 pg->post_compact(); // Shared spaces verification. | |
| 427 } |