Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp @ 1706:9d7a8ab3736b
6962589: remove breadth first scanning code from parallel gc
Summary: Remove the breadth-first copying order from ParallelScavenge and use depth-first by default.
Reviewed-by: jcoomes, ysr, johnc
| author | tonyp |
|---|---|
| date | Thu, 22 Jul 2010 10:27:41 -0400 |
| parents | b2a00dd3117c |
| children | 894b1d7c7e01 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2002, 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 | |
| 25 | |
| 26 # include "incls/_precompiled.incl" | |
| 27 # include "incls/_psScavenge.cpp.incl" | |
| 28 | |
| 29 HeapWord* PSScavenge::_to_space_top_before_gc = NULL; | |
| 30 int PSScavenge::_consecutive_skipped_scavenges = 0; | |
| 31 ReferenceProcessor* PSScavenge::_ref_processor = NULL; | |
| 32 CardTableExtension* PSScavenge::_card_table = NULL; | |
| 33 bool PSScavenge::_survivor_overflow = false; | |
| 34 int PSScavenge::_tenuring_threshold = 0; | |
| 35 HeapWord* PSScavenge::_young_generation_boundary = NULL; | |
| 36 elapsedTimer PSScavenge::_accumulated_time; | |
| 37 GrowableArray<markOop>* PSScavenge::_preserved_mark_stack = NULL; | |
| 38 GrowableArray<oop>* PSScavenge::_preserved_oop_stack = NULL; | |
| 39 CollectorCounters* PSScavenge::_counters = NULL; | |
| 40 | |
| 41 // Define before use | |
| 42 class PSIsAliveClosure: public BoolObjectClosure { | |
| 43 public: | |
| 44 void do_object(oop p) { | |
| 45 assert(false, "Do not call."); | |
| 46 } | |
| 47 bool do_object_b(oop p) { | |
| 48 return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded(); | |
| 49 } | |
| 50 }; | |
| 51 | |
| 52 PSIsAliveClosure PSScavenge::_is_alive_closure; | |
| 53 | |
| 54 class PSKeepAliveClosure: public OopClosure { | |
| 55 protected: | |
| 56 MutableSpace* _to_space; | |
| 57 PSPromotionManager* _promotion_manager; | |
| 58 | |
| 59 public: | |
| 60 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) { | |
| 61 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 62 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 63 _to_space = heap->young_gen()->to_space(); | |
| 64 | |
| 65 assert(_promotion_manager != NULL, "Sanity"); | |
| 66 } | |
| 67 | |
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68 template <class T> void do_oop_work(T* p) { |
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69 assert (!oopDesc::is_null(*p), "expected non-null ref"); |
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70 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(), |
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71 "expected an oop while scanning weak refs"); |
| 0 | 72 |
| 73 // Weak refs may be visited more than once. | |
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74 if (PSScavenge::should_scavenge(p, _to_space)) { |
| 0 | 75 PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p); |
| 76 } | |
| 77 } | |
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78 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); } |
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79 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); } |
| 0 | 80 }; |
| 81 | |
| 82 class PSEvacuateFollowersClosure: public VoidClosure { | |
| 83 private: | |
| 84 PSPromotionManager* _promotion_manager; | |
| 85 public: | |
| 86 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {} | |
| 87 | |
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88 virtual void do_void() { |
| 0 | 89 assert(_promotion_manager != NULL, "Sanity"); |
| 90 _promotion_manager->drain_stacks(true); | |
| 91 guarantee(_promotion_manager->stacks_empty(), | |
| 92 "stacks should be empty at this point"); | |
| 93 } | |
| 94 }; | |
| 95 | |
| 96 class PSPromotionFailedClosure : public ObjectClosure { | |
| 97 virtual void do_object(oop obj) { | |
| 98 if (obj->is_forwarded()) { | |
| 99 obj->init_mark(); | |
| 100 } | |
| 101 } | |
| 102 }; | |
| 103 | |
| 104 class PSRefProcTaskProxy: public GCTask { | |
| 105 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; | |
| 106 ProcessTask & _rp_task; | |
| 107 uint _work_id; | |
| 108 public: | |
| 109 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id) | |
| 110 : _rp_task(rp_task), | |
| 111 _work_id(work_id) | |
| 112 { } | |
| 113 | |
| 114 private: | |
| 115 virtual char* name() { return (char *)"Process referents by policy in parallel"; } | |
| 116 virtual void do_it(GCTaskManager* manager, uint which); | |
| 117 }; | |
| 118 | |
| 119 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which) | |
| 120 { | |
| 121 PSPromotionManager* promotion_manager = | |
| 122 PSPromotionManager::gc_thread_promotion_manager(which); | |
| 123 assert(promotion_manager != NULL, "sanity check"); | |
| 124 PSKeepAliveClosure keep_alive(promotion_manager); | |
| 125 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
| 126 PSIsAliveClosure is_alive; | |
| 127 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers); | |
| 128 } | |
| 129 | |
| 130 class PSRefEnqueueTaskProxy: public GCTask { | |
| 131 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; | |
| 132 EnqueueTask& _enq_task; | |
| 133 uint _work_id; | |
| 134 | |
| 135 public: | |
| 136 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id) | |
| 137 : _enq_task(enq_task), | |
| 138 _work_id(work_id) | |
| 139 { } | |
| 140 | |
| 141 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; } | |
| 142 virtual void do_it(GCTaskManager* manager, uint which) | |
| 143 { | |
| 144 _enq_task.work(_work_id); | |
| 145 } | |
| 146 }; | |
| 147 | |
| 148 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
| 149 virtual void execute(ProcessTask& task); | |
| 150 virtual void execute(EnqueueTask& task); | |
| 151 }; | |
| 152 | |
| 153 void PSRefProcTaskExecutor::execute(ProcessTask& task) | |
| 154 { | |
| 155 GCTaskQueue* q = GCTaskQueue::create(); | |
| 156 for(uint i=0; i<ParallelGCThreads; i++) { | |
| 157 q->enqueue(new PSRefProcTaskProxy(task, i)); | |
| 158 } | |
| 159 ParallelTaskTerminator terminator( | |
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160 ParallelScavengeHeap::gc_task_manager()->workers(), |
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161 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth()); |
| 0 | 162 if (task.marks_oops_alive() && ParallelGCThreads > 1) { |
| 163 for (uint j=0; j<ParallelGCThreads; j++) { | |
| 164 q->enqueue(new StealTask(&terminator)); | |
| 165 } | |
| 166 } | |
| 167 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
| 168 } | |
| 169 | |
| 170 | |
| 171 void PSRefProcTaskExecutor::execute(EnqueueTask& task) | |
| 172 { | |
| 173 GCTaskQueue* q = GCTaskQueue::create(); | |
| 174 for(uint i=0; i<ParallelGCThreads; i++) { | |
| 175 q->enqueue(new PSRefEnqueueTaskProxy(task, i)); | |
| 176 } | |
| 177 ParallelScavengeHeap::gc_task_manager()->execute_and_wait(q); | |
| 178 } | |
| 179 | |
| 180 // This method contains all heap specific policy for invoking scavenge. | |
| 181 // PSScavenge::invoke_no_policy() will do nothing but attempt to | |
| 182 // scavenge. It will not clean up after failed promotions, bail out if | |
| 183 // we've exceeded policy time limits, or any other special behavior. | |
| 184 // All such policy should be placed here. | |
| 185 // | |
| 186 // Note that this method should only be called from the vm_thread while | |
| 187 // at a safepoint! | |
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188 void PSScavenge::invoke() { |
| 0 | 189 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
| 190 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
| 191 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
| 192 | |
| 193 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 194 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 195 | |
| 196 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
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197 IsGCActiveMark mark; |
| 0 | 198 |
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199 bool scavenge_was_done = PSScavenge::invoke_no_policy(); |
| 0 | 200 |
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201 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
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202 if (UsePerfData) |
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203 counters->update_full_follows_scavenge(0); |
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204 if (!scavenge_was_done || |
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205 policy->should_full_GC(heap->old_gen()->free_in_bytes())) { |
| 0 | 206 if (UsePerfData) |
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207 counters->update_full_follows_scavenge(full_follows_scavenge); |
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208 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); |
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209 CollectorPolicy* cp = heap->collector_policy(); |
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210 const bool clear_all_softrefs = cp->should_clear_all_soft_refs(); |
| 0 | 211 |
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212 if (UseParallelOldGC) { |
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213 PSParallelCompact::invoke_no_policy(clear_all_softrefs); |
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214 } else { |
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215 PSMarkSweep::invoke_no_policy(clear_all_softrefs); |
| 0 | 216 } |
| 217 } | |
| 218 } | |
| 219 | |
| 220 // This method contains no policy. You should probably | |
| 221 // be calling invoke() instead. | |
| 222 bool PSScavenge::invoke_no_policy() { | |
| 223 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
| 224 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
| 225 | |
| 226 TimeStamp scavenge_entry; | |
| 227 TimeStamp scavenge_midpoint; | |
| 228 TimeStamp scavenge_exit; | |
| 229 | |
| 230 scavenge_entry.update(); | |
| 231 | |
| 232 if (GC_locker::check_active_before_gc()) { | |
| 233 return false; | |
| 234 } | |
| 235 | |
| 236 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 237 GCCause::Cause gc_cause = heap->gc_cause(); | |
| 238 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 239 | |
| 240 // Check for potential problems. | |
| 241 if (!should_attempt_scavenge()) { | |
| 242 return false; | |
| 243 } | |
| 244 | |
| 245 bool promotion_failure_occurred = false; | |
| 246 | |
| 247 PSYoungGen* young_gen = heap->young_gen(); | |
| 248 PSOldGen* old_gen = heap->old_gen(); | |
| 249 PSPermGen* perm_gen = heap->perm_gen(); | |
| 250 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
| 251 heap->increment_total_collections(); | |
| 252 | |
| 253 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
| 254 | |
| 255 if ((gc_cause != GCCause::_java_lang_system_gc) || | |
| 256 UseAdaptiveSizePolicyWithSystemGC) { | |
| 257 // Gather the feedback data for eden occupancy. | |
| 258 young_gen->eden_space()->accumulate_statistics(); | |
| 259 } | |
| 260 | |
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261 if (ZapUnusedHeapArea) { |
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262 // Save information needed to minimize mangling |
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263 heap->record_gen_tops_before_GC(); |
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264 } |
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265 |
| 0 | 266 if (PrintHeapAtGC) { |
| 267 Universe::print_heap_before_gc(); | |
| 268 } | |
| 269 | |
| 270 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity"); | |
| 271 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity"); | |
| 272 | |
| 273 size_t prev_used = heap->used(); | |
| 274 assert(promotion_failed() == false, "Sanity"); | |
| 275 | |
| 276 // Fill in TLABs | |
| 277 heap->accumulate_statistics_all_tlabs(); | |
| 278 heap->ensure_parsability(true); // retire TLABs | |
| 279 | |
| 280 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
| 281 HandleMark hm; // Discard invalid handles created during verification | |
| 282 gclog_or_tty->print(" VerifyBeforeGC:"); | |
| 283 Universe::verify(true); | |
| 284 } | |
| 285 | |
| 286 { | |
| 287 ResourceMark rm; | |
| 288 HandleMark hm; | |
| 289 | |
| 290 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
| 291 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 292 TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty); | |
| 293 TraceCollectorStats tcs(counters()); | |
| 294 TraceMemoryManagerStats tms(false /* not full GC */); | |
| 295 | |
| 296 if (TraceGen0Time) accumulated_time()->start(); | |
| 297 | |
| 298 // Let the size policy know we're starting | |
| 299 size_policy->minor_collection_begin(); | |
| 300 | |
| 301 // Verify the object start arrays. | |
| 302 if (VerifyObjectStartArray && | |
| 303 VerifyBeforeGC) { | |
| 304 old_gen->verify_object_start_array(); | |
| 305 perm_gen->verify_object_start_array(); | |
| 306 } | |
| 307 | |
| 308 // Verify no unmarked old->young roots | |
| 309 if (VerifyRememberedSets) { | |
| 310 CardTableExtension::verify_all_young_refs_imprecise(); | |
| 311 } | |
| 312 | |
| 313 if (!ScavengeWithObjectsInToSpace) { | |
| 314 assert(young_gen->to_space()->is_empty(), | |
| 315 "Attempt to scavenge with live objects in to_space"); | |
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316 young_gen->to_space()->clear(SpaceDecorator::Mangle); |
| 0 | 317 } else if (ZapUnusedHeapArea) { |
| 318 young_gen->to_space()->mangle_unused_area(); | |
| 319 } | |
| 320 save_to_space_top_before_gc(); | |
| 321 | |
| 322 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
| 323 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
| 324 | |
| 325 reference_processor()->enable_discovery(); | |
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326 reference_processor()->setup_policy(false); |
| 0 | 327 |
| 328 // We track how much was promoted to the next generation for | |
| 329 // the AdaptiveSizePolicy. | |
| 330 size_t old_gen_used_before = old_gen->used_in_bytes(); | |
| 331 | |
| 332 // For PrintGCDetails | |
| 333 size_t young_gen_used_before = young_gen->used_in_bytes(); | |
| 334 | |
| 335 // Reset our survivor overflow. | |
| 336 set_survivor_overflow(false); | |
| 337 | |
| 338 // We need to save the old/perm top values before | |
| 339 // creating the promotion_manager. We pass the top | |
| 340 // values to the card_table, to prevent it from | |
| 341 // straying into the promotion labs. | |
| 342 HeapWord* old_top = old_gen->object_space()->top(); | |
| 343 HeapWord* perm_top = perm_gen->object_space()->top(); | |
| 344 | |
| 345 // Release all previously held resources | |
| 346 gc_task_manager()->release_all_resources(); | |
| 347 | |
| 348 PSPromotionManager::pre_scavenge(); | |
| 349 | |
| 350 // We'll use the promotion manager again later. | |
| 351 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); | |
| 352 { | |
| 353 // TraceTime("Roots"); | |
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354 ParallelScavengeHeap::ParStrongRootsScope psrs; |
| 0 | 355 |
| 356 GCTaskQueue* q = GCTaskQueue::create(); | |
| 357 | |
| 358 for(uint i=0; i<ParallelGCThreads; i++) { | |
| 359 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i)); | |
| 360 } | |
| 361 | |
| 362 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); | |
| 363 | |
| 364 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); | |
| 365 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); | |
| 366 // We scan the thread roots in parallel | |
| 367 Threads::create_thread_roots_tasks(q); | |
| 368 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); | |
| 369 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); | |
| 370 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); | |
| 371 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); | |
| 372 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); | |
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373 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache)); |
| 0 | 374 |
| 375 ParallelTaskTerminator terminator( | |
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376 gc_task_manager()->workers(), |
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377 (TaskQueueSetSuper*) promotion_manager->stack_array_depth()); |
| 0 | 378 if (ParallelGCThreads>1) { |
| 379 for (uint j=0; j<ParallelGCThreads; j++) { | |
| 380 q->enqueue(new StealTask(&terminator)); | |
| 381 } | |
| 382 } | |
| 383 | |
| 384 gc_task_manager()->execute_and_wait(q); | |
| 385 } | |
| 386 | |
| 387 scavenge_midpoint.update(); | |
| 388 | |
| 389 // Process reference objects discovered during scavenge | |
| 390 { | |
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391 reference_processor()->setup_policy(false); // not always_clear |
| 0 | 392 PSKeepAliveClosure keep_alive(promotion_manager); |
| 393 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
| 394 if (reference_processor()->processing_is_mt()) { | |
| 395 PSRefProcTaskExecutor task_executor; | |
| 396 reference_processor()->process_discovered_references( | |
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397 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor); |
| 0 | 398 } else { |
| 399 reference_processor()->process_discovered_references( | |
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400 &_is_alive_closure, &keep_alive, &evac_followers, NULL); |
| 0 | 401 } |
| 402 } | |
| 403 | |
| 404 // Enqueue reference objects discovered during scavenge. | |
| 405 if (reference_processor()->processing_is_mt()) { | |
| 406 PSRefProcTaskExecutor task_executor; | |
| 407 reference_processor()->enqueue_discovered_references(&task_executor); | |
| 408 } else { | |
| 409 reference_processor()->enqueue_discovered_references(NULL); | |
| 410 } | |
| 411 | |
| 412 // Finally, flush the promotion_manager's labs, and deallocate its stacks. | |
| 413 PSPromotionManager::post_scavenge(); | |
| 414 | |
| 415 promotion_failure_occurred = promotion_failed(); | |
| 416 if (promotion_failure_occurred) { | |
| 417 clean_up_failed_promotion(); | |
| 418 if (PrintGC) { | |
| 419 gclog_or_tty->print("--"); | |
| 420 } | |
| 421 } | |
| 422 | |
| 423 // Let the size policy know we're done. Note that we count promotion | |
| 424 // failure cleanup time as part of the collection (otherwise, we're | |
| 425 // implicitly saying it's mutator time). | |
| 426 size_policy->minor_collection_end(gc_cause); | |
| 427 | |
| 428 if (!promotion_failure_occurred) { | |
| 429 // Swap the survivor spaces. | |
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430 |
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431 |
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432 young_gen->eden_space()->clear(SpaceDecorator::Mangle); |
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433 young_gen->from_space()->clear(SpaceDecorator::Mangle); |
| 0 | 434 young_gen->swap_spaces(); |
| 435 | |
| 436 size_t survived = young_gen->from_space()->used_in_bytes(); | |
| 437 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; | |
| 438 size_policy->update_averages(_survivor_overflow, survived, promoted); | |
| 439 | |
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440 // A successful scavenge should restart the GC time limit count which is |
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441 // for full GC's. |
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442 size_policy->reset_gc_overhead_limit_count(); |
| 0 | 443 if (UseAdaptiveSizePolicy) { |
| 444 // Calculate the new survivor size and tenuring threshold | |
| 445 | |
| 446 if (PrintAdaptiveSizePolicy) { | |
| 447 gclog_or_tty->print("AdaptiveSizeStart: "); | |
| 448 gclog_or_tty->stamp(); | |
| 449 gclog_or_tty->print_cr(" collection: %d ", | |
| 450 heap->total_collections()); | |
| 451 | |
| 452 if (Verbose) { | |
| 453 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
| 454 " perm_gen_capacity: %d ", | |
| 455 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
| 456 perm_gen->capacity_in_bytes()); | |
| 457 } | |
| 458 } | |
| 459 | |
| 460 | |
| 461 if (UsePerfData) { | |
| 462 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 463 counters->update_old_eden_size( | |
| 464 size_policy->calculated_eden_size_in_bytes()); | |
| 465 counters->update_old_promo_size( | |
| 466 size_policy->calculated_promo_size_in_bytes()); | |
| 467 counters->update_old_capacity(old_gen->capacity_in_bytes()); | |
| 468 counters->update_young_capacity(young_gen->capacity_in_bytes()); | |
| 469 counters->update_survived(survived); | |
| 470 counters->update_promoted(promoted); | |
| 471 counters->update_survivor_overflowed(_survivor_overflow); | |
| 472 } | |
| 473 | |
| 474 size_t survivor_limit = | |
| 475 size_policy->max_survivor_size(young_gen->max_size()); | |
| 476 _tenuring_threshold = | |
| 477 size_policy->compute_survivor_space_size_and_threshold( | |
| 478 _survivor_overflow, | |
| 479 _tenuring_threshold, | |
| 480 survivor_limit); | |
| 481 | |
| 482 if (PrintTenuringDistribution) { | |
| 483 gclog_or_tty->cr(); | |
| 484 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", | |
| 485 size_policy->calculated_survivor_size_in_bytes(), | |
| 486 _tenuring_threshold, MaxTenuringThreshold); | |
| 487 } | |
| 488 | |
| 489 if (UsePerfData) { | |
| 490 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 491 counters->update_tenuring_threshold(_tenuring_threshold); | |
| 492 counters->update_survivor_size_counters(); | |
| 493 } | |
| 494 | |
| 495 // Do call at minor collections? | |
| 496 // Don't check if the size_policy is ready at this | |
| 497 // level. Let the size_policy check that internally. | |
| 498 if (UseAdaptiveSizePolicy && | |
| 499 UseAdaptiveGenerationSizePolicyAtMinorCollection && | |
| 500 ((gc_cause != GCCause::_java_lang_system_gc) || | |
| 501 UseAdaptiveSizePolicyWithSystemGC)) { | |
| 502 | |
| 503 // Calculate optimial free space amounts | |
| 504 assert(young_gen->max_size() > | |
| 505 young_gen->from_space()->capacity_in_bytes() + | |
| 506 young_gen->to_space()->capacity_in_bytes(), | |
| 507 "Sizes of space in young gen are out-of-bounds"); | |
| 508 size_t max_eden_size = young_gen->max_size() - | |
| 509 young_gen->from_space()->capacity_in_bytes() - | |
| 510 young_gen->to_space()->capacity_in_bytes(); | |
| 511 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
| 512 young_gen->eden_space()->used_in_bytes(), | |
| 513 old_gen->used_in_bytes(), | |
| 514 perm_gen->used_in_bytes(), | |
| 515 young_gen->eden_space()->capacity_in_bytes(), | |
| 516 old_gen->max_gen_size(), | |
| 517 max_eden_size, | |
| 518 false /* full gc*/, | |
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519 gc_cause, |
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520 heap->collector_policy()); |
| 0 | 521 |
| 522 } | |
| 523 // Resize the young generation at every collection | |
| 524 // even if new sizes have not been calculated. This is | |
| 525 // to allow resizes that may have been inhibited by the | |
| 526 // relative location of the "to" and "from" spaces. | |
| 527 | |
| 528 // Resizing the old gen at minor collects can cause increases | |
| 529 // that don't feed back to the generation sizing policy until | |
| 530 // a major collection. Don't resize the old gen here. | |
| 531 | |
| 532 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), | |
| 533 size_policy->calculated_survivor_size_in_bytes()); | |
| 534 | |
| 535 if (PrintAdaptiveSizePolicy) { | |
| 536 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
| 537 heap->total_collections()); | |
| 538 } | |
| 539 } | |
| 540 | |
| 541 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can | |
| 542 // cause the change of the heap layout. Make sure eden is reshaped if that's the case. | |
| 543 // Also update() will case adaptive NUMA chunk resizing. | |
| 544 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); | |
| 545 young_gen->eden_space()->update(); | |
| 546 | |
| 547 heap->gc_policy_counters()->update_counters(); | |
| 548 | |
| 549 heap->resize_all_tlabs(); | |
| 550 | |
| 551 assert(young_gen->to_space()->is_empty(), "to space should be empty now"); | |
| 552 } | |
| 553 | |
| 554 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
| 555 | |
| 556 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
| 557 | |
| 558 // Re-verify object start arrays | |
| 559 if (VerifyObjectStartArray && | |
| 560 VerifyAfterGC) { | |
| 561 old_gen->verify_object_start_array(); | |
| 562 perm_gen->verify_object_start_array(); | |
| 563 } | |
| 564 | |
| 565 // Verify all old -> young cards are now precise | |
| 566 if (VerifyRememberedSets) { | |
| 567 // Precise verification will give false positives. Until this is fixed, | |
| 568 // use imprecise verification. | |
| 569 // CardTableExtension::verify_all_young_refs_precise(); | |
| 570 CardTableExtension::verify_all_young_refs_imprecise(); | |
| 571 } | |
| 572 | |
| 573 if (TraceGen0Time) accumulated_time()->stop(); | |
| 574 | |
| 575 if (PrintGC) { | |
| 576 if (PrintGCDetails) { | |
| 577 // Don't print a GC timestamp here. This is after the GC so | |
| 578 // would be confusing. | |
| 579 young_gen->print_used_change(young_gen_used_before); | |
| 580 } | |
| 581 heap->print_heap_change(prev_used); | |
| 582 } | |
| 583 | |
| 584 // Track memory usage and detect low memory | |
| 585 MemoryService::track_memory_usage(); | |
| 586 heap->update_counters(); | |
| 587 } | |
| 588 | |
| 589 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
| 590 HandleMark hm; // Discard invalid handles created during verification | |
| 591 gclog_or_tty->print(" VerifyAfterGC:"); | |
| 592 Universe::verify(false); | |
| 593 } | |
| 594 | |
| 595 if (PrintHeapAtGC) { | |
| 596 Universe::print_heap_after_gc(); | |
| 597 } | |
| 598 | |
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599 if (ZapUnusedHeapArea) { |
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600 young_gen->eden_space()->check_mangled_unused_area_complete(); |
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601 young_gen->from_space()->check_mangled_unused_area_complete(); |
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602 young_gen->to_space()->check_mangled_unused_area_complete(); |
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603 } |
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604 |
| 0 | 605 scavenge_exit.update(); |
| 606 | |
| 607 if (PrintGCTaskTimeStamps) { | |
| 608 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, | |
| 609 scavenge_entry.ticks(), scavenge_midpoint.ticks(), | |
| 610 scavenge_exit.ticks()); | |
| 611 gc_task_manager()->print_task_time_stamps(); | |
| 612 } | |
| 613 | |
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614 #ifdef TRACESPINNING |
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615 ParallelTaskTerminator::print_termination_counts(); |
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616 #endif |
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617 |
| 0 | 618 return !promotion_failure_occurred; |
| 619 } | |
| 620 | |
| 621 // This method iterates over all objects in the young generation, | |
| 622 // unforwarding markOops. It then restores any preserved mark oops, | |
| 623 // and clears the _preserved_mark_stack. | |
| 624 void PSScavenge::clean_up_failed_promotion() { | |
| 625 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 626 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 627 assert(promotion_failed(), "Sanity"); | |
| 628 | |
| 629 PSYoungGen* young_gen = heap->young_gen(); | |
| 630 | |
| 631 { | |
| 632 ResourceMark rm; | |
| 633 | |
| 634 // Unforward all pointers in the young gen. | |
| 635 PSPromotionFailedClosure unforward_closure; | |
| 636 young_gen->object_iterate(&unforward_closure); | |
| 637 | |
| 638 if (PrintGC && Verbose) { | |
| 639 gclog_or_tty->print_cr("Restoring %d marks", | |
| 640 _preserved_oop_stack->length()); | |
| 641 } | |
| 642 | |
| 643 // Restore any saved marks. | |
| 644 for (int i=0; i < _preserved_oop_stack->length(); i++) { | |
| 645 oop obj = _preserved_oop_stack->at(i); | |
| 646 markOop mark = _preserved_mark_stack->at(i); | |
| 647 obj->set_mark(mark); | |
| 648 } | |
| 649 | |
| 650 // Deallocate the preserved mark and oop stacks. | |
| 651 // The stacks were allocated as CHeap objects, so | |
| 652 // we must call delete to prevent mem leaks. | |
| 653 delete _preserved_mark_stack; | |
| 654 _preserved_mark_stack = NULL; | |
| 655 delete _preserved_oop_stack; | |
| 656 _preserved_oop_stack = NULL; | |
| 657 } | |
| 658 | |
| 659 // Reset the PromotionFailureALot counters. | |
| 660 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) | |
| 661 } | |
| 662 | |
| 663 // This method is called whenever an attempt to promote an object | |
| 664 // fails. Some markOops will need preserving, some will not. Note | |
| 665 // that the entire eden is traversed after a failed promotion, with | |
| 666 // all forwarded headers replaced by the default markOop. This means | |
| 667 // it is not neccessary to preserve most markOops. | |
| 668 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { | |
| 669 if (_preserved_mark_stack == NULL) { | |
| 670 ThreadCritical tc; // Lock and retest | |
| 671 if (_preserved_mark_stack == NULL) { | |
| 672 assert(_preserved_oop_stack == NULL, "Sanity"); | |
| 673 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true); | |
| 674 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true); | |
| 675 } | |
| 676 } | |
| 677 | |
| 678 // Because we must hold the ThreadCritical lock before using | |
| 679 // the stacks, we should be safe from observing partial allocations, | |
| 680 // which are also guarded by the ThreadCritical lock. | |
| 681 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { | |
| 682 ThreadCritical tc; | |
| 683 _preserved_oop_stack->push(obj); | |
| 684 _preserved_mark_stack->push(obj_mark); | |
| 685 } | |
| 686 } | |
| 687 | |
| 688 bool PSScavenge::should_attempt_scavenge() { | |
| 689 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 690 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 691 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 692 | |
| 693 if (UsePerfData) { | |
| 694 counters->update_scavenge_skipped(not_skipped); | |
| 695 } | |
| 696 | |
| 697 PSYoungGen* young_gen = heap->young_gen(); | |
| 698 PSOldGen* old_gen = heap->old_gen(); | |
| 699 | |
| 700 if (!ScavengeWithObjectsInToSpace) { | |
| 701 // Do not attempt to promote unless to_space is empty | |
| 702 if (!young_gen->to_space()->is_empty()) { | |
| 703 _consecutive_skipped_scavenges++; | |
| 704 if (UsePerfData) { | |
| 705 counters->update_scavenge_skipped(to_space_not_empty); | |
| 706 } | |
| 707 return false; | |
| 708 } | |
| 709 } | |
| 710 | |
| 711 // Test to see if the scavenge will likely fail. | |
| 712 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
| 713 | |
| 714 // A similar test is done in the policy's should_full_GC(). If this is | |
| 715 // changed, decide if that test should also be changed. | |
| 716 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); | |
| 717 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); | |
| 718 bool result = promotion_estimate < old_gen->free_in_bytes(); | |
| 719 | |
| 720 if (PrintGCDetails && Verbose) { | |
| 721 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); | |
| 722 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
| 723 " padded_average_promoted " SIZE_FORMAT | |
| 724 " free in old gen " SIZE_FORMAT, | |
| 725 (size_t) policy->average_promoted_in_bytes(), | |
| 726 (size_t) policy->padded_average_promoted_in_bytes(), | |
| 727 old_gen->free_in_bytes()); | |
| 728 if (young_gen->used_in_bytes() < | |
| 729 (size_t) policy->padded_average_promoted_in_bytes()) { | |
| 730 gclog_or_tty->print_cr(" padded_promoted_average is greater" | |
| 731 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); | |
| 732 } | |
| 733 } | |
| 734 | |
| 735 if (result) { | |
| 736 _consecutive_skipped_scavenges = 0; | |
| 737 } else { | |
| 738 _consecutive_skipped_scavenges++; | |
| 739 if (UsePerfData) { | |
| 740 counters->update_scavenge_skipped(promoted_too_large); | |
| 741 } | |
| 742 } | |
| 743 return result; | |
| 744 } | |
| 745 | |
| 746 // Used to add tasks | |
| 747 GCTaskManager* const PSScavenge::gc_task_manager() { | |
| 748 assert(ParallelScavengeHeap::gc_task_manager() != NULL, | |
| 749 "shouldn't return NULL"); | |
| 750 return ParallelScavengeHeap::gc_task_manager(); | |
| 751 } | |
| 752 | |
| 753 void PSScavenge::initialize() { | |
| 754 // Arguments must have been parsed | |
| 755 | |
| 756 if (AlwaysTenure) { | |
| 757 _tenuring_threshold = 0; | |
| 758 } else if (NeverTenure) { | |
| 759 _tenuring_threshold = markOopDesc::max_age + 1; | |
| 760 } else { | |
| 761 // We want to smooth out our startup times for the AdaptiveSizePolicy | |
| 762 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : | |
| 763 MaxTenuringThreshold; | |
| 764 } | |
| 765 | |
| 766 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 767 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 768 | |
| 769 PSYoungGen* young_gen = heap->young_gen(); | |
| 770 PSOldGen* old_gen = heap->old_gen(); | |
| 771 PSPermGen* perm_gen = heap->perm_gen(); | |
| 772 | |
| 773 // Set boundary between young_gen and old_gen | |
| 774 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), | |
| 775 "perm above old"); | |
| 776 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), | |
| 777 "old above young"); | |
| 778 _young_generation_boundary = young_gen->eden_space()->bottom(); | |
| 779 | |
| 780 // Initialize ref handling object for scavenging. | |
| 781 MemRegion mr = young_gen->reserved(); | |
| 782 _ref_processor = ReferenceProcessor::create_ref_processor( | |
| 783 mr, // span | |
| 784 true, // atomic_discovery | |
| 785 true, // mt_discovery | |
| 786 NULL, // is_alive_non_header | |
| 787 ParallelGCThreads, | |
| 788 ParallelRefProcEnabled); | |
| 789 | |
| 790 // Cache the cardtable | |
| 791 BarrierSet* bs = Universe::heap()->barrier_set(); | |
| 792 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); | |
| 793 _card_table = (CardTableExtension*)bs; | |
| 794 | |
| 795 _counters = new CollectorCounters("PSScavenge", 0); | |
| 796 } |