Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp @ 4095:bca17e38de00
6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
Summary: Select number of GC threads dynamically based on heap usage and number of Java threads
Reviewed-by: johnc, ysr, jcoomes
| author | jmasa |
|---|---|
| date | Tue, 09 Aug 2011 10:16:01 -0700 |
| parents | 4dfb2df418f2 |
| children | aa3d708d67c4 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 2002, 2011, 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" |
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26 #include "classfile/symbolTable.hpp" |
| 1972 | 27 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp" |
| 28 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp" | |
| 29 #include "gc_implementation/parallelScavenge/generationSizer.hpp" | |
| 30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" | |
| 31 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" | |
| 32 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp" | |
| 33 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp" | |
| 34 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp" | |
| 35 #include "gc_implementation/parallelScavenge/psTasks.hpp" | |
| 36 #include "gc_implementation/shared/isGCActiveMark.hpp" | |
| 37 #include "gc_implementation/shared/spaceDecorator.hpp" | |
| 38 #include "gc_interface/gcCause.hpp" | |
| 39 #include "memory/collectorPolicy.hpp" | |
| 40 #include "memory/gcLocker.inline.hpp" | |
| 41 #include "memory/referencePolicy.hpp" | |
| 42 #include "memory/referenceProcessor.hpp" | |
| 43 #include "memory/resourceArea.hpp" | |
| 44 #include "oops/oop.inline.hpp" | |
| 45 #include "oops/oop.psgc.inline.hpp" | |
| 46 #include "runtime/biasedLocking.hpp" | |
| 47 #include "runtime/fprofiler.hpp" | |
| 48 #include "runtime/handles.inline.hpp" | |
| 49 #include "runtime/threadCritical.hpp" | |
| 50 #include "runtime/vmThread.hpp" | |
| 51 #include "runtime/vm_operations.hpp" | |
| 52 #include "services/memoryService.hpp" | |
| 53 #include "utilities/stack.inline.hpp" | |
| 0 | 54 |
| 55 | |
| 56 HeapWord* PSScavenge::_to_space_top_before_gc = NULL; | |
| 57 int PSScavenge::_consecutive_skipped_scavenges = 0; | |
| 58 ReferenceProcessor* PSScavenge::_ref_processor = NULL; | |
| 59 CardTableExtension* PSScavenge::_card_table = NULL; | |
| 60 bool PSScavenge::_survivor_overflow = false; | |
| 61 int PSScavenge::_tenuring_threshold = 0; | |
| 62 HeapWord* PSScavenge::_young_generation_boundary = NULL; | |
| 63 elapsedTimer PSScavenge::_accumulated_time; | |
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64 Stack<markOop> PSScavenge::_preserved_mark_stack; |
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65 Stack<oop> PSScavenge::_preserved_oop_stack; |
| 0 | 66 CollectorCounters* PSScavenge::_counters = NULL; |
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67 bool PSScavenge::_promotion_failed = false; |
| 0 | 68 |
| 69 // Define before use | |
| 70 class PSIsAliveClosure: public BoolObjectClosure { | |
| 71 public: | |
| 72 void do_object(oop p) { | |
| 73 assert(false, "Do not call."); | |
| 74 } | |
| 75 bool do_object_b(oop p) { | |
| 76 return (!PSScavenge::is_obj_in_young((HeapWord*) p)) || p->is_forwarded(); | |
| 77 } | |
| 78 }; | |
| 79 | |
| 80 PSIsAliveClosure PSScavenge::_is_alive_closure; | |
| 81 | |
| 82 class PSKeepAliveClosure: public OopClosure { | |
| 83 protected: | |
| 84 MutableSpace* _to_space; | |
| 85 PSPromotionManager* _promotion_manager; | |
| 86 | |
| 87 public: | |
| 88 PSKeepAliveClosure(PSPromotionManager* pm) : _promotion_manager(pm) { | |
| 89 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 90 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 91 _to_space = heap->young_gen()->to_space(); | |
| 92 | |
| 93 assert(_promotion_manager != NULL, "Sanity"); | |
| 94 } | |
| 95 | |
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96 template <class T> void do_oop_work(T* p) { |
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97 assert (!oopDesc::is_null(*p), "expected non-null ref"); |
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98 assert ((oopDesc::load_decode_heap_oop_not_null(p))->is_oop(), |
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99 "expected an oop while scanning weak refs"); |
| 0 | 100 |
| 101 // Weak refs may be visited more than once. | |
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102 if (PSScavenge::should_scavenge(p, _to_space)) { |
| 0 | 103 PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p); |
| 104 } | |
| 105 } | |
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106 virtual void do_oop(oop* p) { PSKeepAliveClosure::do_oop_work(p); } |
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107 virtual void do_oop(narrowOop* p) { PSKeepAliveClosure::do_oop_work(p); } |
| 0 | 108 }; |
| 109 | |
| 110 class PSEvacuateFollowersClosure: public VoidClosure { | |
| 111 private: | |
| 112 PSPromotionManager* _promotion_manager; | |
| 113 public: | |
| 114 PSEvacuateFollowersClosure(PSPromotionManager* pm) : _promotion_manager(pm) {} | |
| 115 | |
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116 virtual void do_void() { |
| 0 | 117 assert(_promotion_manager != NULL, "Sanity"); |
| 118 _promotion_manager->drain_stacks(true); | |
| 119 guarantee(_promotion_manager->stacks_empty(), | |
| 120 "stacks should be empty at this point"); | |
| 121 } | |
| 122 }; | |
| 123 | |
| 124 class PSPromotionFailedClosure : public ObjectClosure { | |
| 125 virtual void do_object(oop obj) { | |
| 126 if (obj->is_forwarded()) { | |
| 127 obj->init_mark(); | |
| 128 } | |
| 129 } | |
| 130 }; | |
| 131 | |
| 132 class PSRefProcTaskProxy: public GCTask { | |
| 133 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask; | |
| 134 ProcessTask & _rp_task; | |
| 135 uint _work_id; | |
| 136 public: | |
| 137 PSRefProcTaskProxy(ProcessTask & rp_task, uint work_id) | |
| 138 : _rp_task(rp_task), | |
| 139 _work_id(work_id) | |
| 140 { } | |
| 141 | |
| 142 private: | |
| 143 virtual char* name() { return (char *)"Process referents by policy in parallel"; } | |
| 144 virtual void do_it(GCTaskManager* manager, uint which); | |
| 145 }; | |
| 146 | |
| 147 void PSRefProcTaskProxy::do_it(GCTaskManager* manager, uint which) | |
| 148 { | |
| 149 PSPromotionManager* promotion_manager = | |
| 150 PSPromotionManager::gc_thread_promotion_manager(which); | |
| 151 assert(promotion_manager != NULL, "sanity check"); | |
| 152 PSKeepAliveClosure keep_alive(promotion_manager); | |
| 153 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
| 154 PSIsAliveClosure is_alive; | |
| 155 _rp_task.work(_work_id, is_alive, keep_alive, evac_followers); | |
| 156 } | |
| 157 | |
| 158 class PSRefEnqueueTaskProxy: public GCTask { | |
| 159 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask; | |
| 160 EnqueueTask& _enq_task; | |
| 161 uint _work_id; | |
| 162 | |
| 163 public: | |
| 164 PSRefEnqueueTaskProxy(EnqueueTask& enq_task, uint work_id) | |
| 165 : _enq_task(enq_task), | |
| 166 _work_id(work_id) | |
| 167 { } | |
| 168 | |
| 169 virtual char* name() { return (char *)"Enqueue reference objects in parallel"; } | |
| 170 virtual void do_it(GCTaskManager* manager, uint which) | |
| 171 { | |
| 172 _enq_task.work(_work_id); | |
| 173 } | |
| 174 }; | |
| 175 | |
| 176 class PSRefProcTaskExecutor: public AbstractRefProcTaskExecutor { | |
| 177 virtual void execute(ProcessTask& task); | |
| 178 virtual void execute(EnqueueTask& task); | |
| 179 }; | |
| 180 | |
| 181 void PSRefProcTaskExecutor::execute(ProcessTask& task) | |
| 182 { | |
| 183 GCTaskQueue* q = GCTaskQueue::create(); | |
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184 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager(); |
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185 for(uint i=0; i < manager->active_workers(); i++) { |
| 0 | 186 q->enqueue(new PSRefProcTaskProxy(task, i)); |
| 187 } | |
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188 ParallelTaskTerminator terminator(manager->active_workers(), |
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189 (TaskQueueSetSuper*) PSPromotionManager::stack_array_depth()); |
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190 if (task.marks_oops_alive() && manager->active_workers() > 1) { |
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191 for (uint j = 0; j < manager->active_workers(); j++) { |
| 0 | 192 q->enqueue(new StealTask(&terminator)); |
| 193 } | |
| 194 } | |
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195 manager->execute_and_wait(q); |
| 0 | 196 } |
| 197 | |
| 198 | |
| 199 void PSRefProcTaskExecutor::execute(EnqueueTask& task) | |
| 200 { | |
| 201 GCTaskQueue* q = GCTaskQueue::create(); | |
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202 GCTaskManager* manager = ParallelScavengeHeap::gc_task_manager(); |
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203 for(uint i=0; i < manager->active_workers(); i++) { |
| 0 | 204 q->enqueue(new PSRefEnqueueTaskProxy(task, i)); |
| 205 } | |
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206 manager->execute_and_wait(q); |
| 0 | 207 } |
| 208 | |
| 209 // This method contains all heap specific policy for invoking scavenge. | |
| 210 // PSScavenge::invoke_no_policy() will do nothing but attempt to | |
| 211 // scavenge. It will not clean up after failed promotions, bail out if | |
| 212 // we've exceeded policy time limits, or any other special behavior. | |
| 213 // All such policy should be placed here. | |
| 214 // | |
| 215 // Note that this method should only be called from the vm_thread while | |
| 216 // at a safepoint! | |
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217 void PSScavenge::invoke() { |
| 0 | 218 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
| 219 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
| 220 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
| 221 | |
| 222 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 223 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 224 | |
| 225 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
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226 IsGCActiveMark mark; |
| 0 | 227 |
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228 bool scavenge_was_done = PSScavenge::invoke_no_policy(); |
| 0 | 229 |
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230 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); |
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231 if (UsePerfData) |
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232 counters->update_full_follows_scavenge(0); |
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233 if (!scavenge_was_done || |
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234 policy->should_full_GC(heap->old_gen()->free_in_bytes())) { |
| 0 | 235 if (UsePerfData) |
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236 counters->update_full_follows_scavenge(full_follows_scavenge); |
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237 GCCauseSetter gccs(heap, GCCause::_adaptive_size_policy); |
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238 CollectorPolicy* cp = heap->collector_policy(); |
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239 const bool clear_all_softrefs = cp->should_clear_all_soft_refs(); |
| 0 | 240 |
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241 if (UseParallelOldGC) { |
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242 PSParallelCompact::invoke_no_policy(clear_all_softrefs); |
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243 } else { |
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244 PSMarkSweep::invoke_no_policy(clear_all_softrefs); |
| 0 | 245 } |
| 246 } | |
| 247 } | |
| 248 | |
| 249 // This method contains no policy. You should probably | |
| 250 // be calling invoke() instead. | |
| 251 bool PSScavenge::invoke_no_policy() { | |
| 252 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
| 253 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
| 254 | |
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255 assert(_preserved_mark_stack.is_empty(), "should be empty"); |
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256 assert(_preserved_oop_stack.is_empty(), "should be empty"); |
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257 |
| 0 | 258 TimeStamp scavenge_entry; |
| 259 TimeStamp scavenge_midpoint; | |
| 260 TimeStamp scavenge_exit; | |
| 261 | |
| 262 scavenge_entry.update(); | |
| 263 | |
| 264 if (GC_locker::check_active_before_gc()) { | |
| 265 return false; | |
| 266 } | |
| 267 | |
| 268 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 269 GCCause::Cause gc_cause = heap->gc_cause(); | |
| 270 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 271 | |
| 272 // Check for potential problems. | |
| 273 if (!should_attempt_scavenge()) { | |
| 274 return false; | |
| 275 } | |
| 276 | |
| 277 bool promotion_failure_occurred = false; | |
| 278 | |
| 279 PSYoungGen* young_gen = heap->young_gen(); | |
| 280 PSOldGen* old_gen = heap->old_gen(); | |
| 281 PSPermGen* perm_gen = heap->perm_gen(); | |
| 282 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
| 283 heap->increment_total_collections(); | |
| 284 | |
| 285 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
| 286 | |
| 287 if ((gc_cause != GCCause::_java_lang_system_gc) || | |
| 288 UseAdaptiveSizePolicyWithSystemGC) { | |
| 289 // Gather the feedback data for eden occupancy. | |
| 290 young_gen->eden_space()->accumulate_statistics(); | |
| 291 } | |
| 292 | |
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293 if (ZapUnusedHeapArea) { |
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294 // Save information needed to minimize mangling |
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295 heap->record_gen_tops_before_GC(); |
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296 } |
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297 |
| 0 | 298 if (PrintHeapAtGC) { |
| 299 Universe::print_heap_before_gc(); | |
| 300 } | |
| 301 | |
| 302 assert(!NeverTenure || _tenuring_threshold == markOopDesc::max_age + 1, "Sanity"); | |
| 303 assert(!AlwaysTenure || _tenuring_threshold == 0, "Sanity"); | |
| 304 | |
| 305 size_t prev_used = heap->used(); | |
| 306 assert(promotion_failed() == false, "Sanity"); | |
| 307 | |
| 308 // Fill in TLABs | |
| 309 heap->accumulate_statistics_all_tlabs(); | |
| 310 heap->ensure_parsability(true); // retire TLABs | |
| 311 | |
| 312 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
| 313 HandleMark hm; // Discard invalid handles created during verification | |
| 314 gclog_or_tty->print(" VerifyBeforeGC:"); | |
| 315 Universe::verify(true); | |
| 316 } | |
| 317 | |
| 318 { | |
| 319 ResourceMark rm; | |
| 320 HandleMark hm; | |
| 321 | |
| 322 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
| 323 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 324 TraceTime t1("GC", PrintGC, !PrintGCDetails, gclog_or_tty); | |
| 325 TraceCollectorStats tcs(counters()); | |
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326 TraceMemoryManagerStats tms(false /* not full GC */,gc_cause); |
| 0 | 327 |
| 328 if (TraceGen0Time) accumulated_time()->start(); | |
| 329 | |
| 330 // Let the size policy know we're starting | |
| 331 size_policy->minor_collection_begin(); | |
| 332 | |
| 333 // Verify the object start arrays. | |
| 334 if (VerifyObjectStartArray && | |
| 335 VerifyBeforeGC) { | |
| 336 old_gen->verify_object_start_array(); | |
| 337 perm_gen->verify_object_start_array(); | |
| 338 } | |
| 339 | |
| 340 // Verify no unmarked old->young roots | |
| 341 if (VerifyRememberedSets) { | |
| 342 CardTableExtension::verify_all_young_refs_imprecise(); | |
| 343 } | |
| 344 | |
| 345 if (!ScavengeWithObjectsInToSpace) { | |
| 346 assert(young_gen->to_space()->is_empty(), | |
| 347 "Attempt to scavenge with live objects in to_space"); | |
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348 young_gen->to_space()->clear(SpaceDecorator::Mangle); |
| 0 | 349 } else if (ZapUnusedHeapArea) { |
| 350 young_gen->to_space()->mangle_unused_area(); | |
| 351 } | |
| 352 save_to_space_top_before_gc(); | |
| 353 | |
| 354 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
| 355 | |
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356 reference_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/); |
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357 reference_processor()->setup_policy(false); |
| 0 | 358 |
| 359 // We track how much was promoted to the next generation for | |
| 360 // the AdaptiveSizePolicy. | |
| 361 size_t old_gen_used_before = old_gen->used_in_bytes(); | |
| 362 | |
| 363 // For PrintGCDetails | |
| 364 size_t young_gen_used_before = young_gen->used_in_bytes(); | |
| 365 | |
| 366 // Reset our survivor overflow. | |
| 367 set_survivor_overflow(false); | |
| 368 | |
| 369 // We need to save the old/perm top values before | |
| 370 // creating the promotion_manager. We pass the top | |
| 371 // values to the card_table, to prevent it from | |
| 372 // straying into the promotion labs. | |
| 373 HeapWord* old_top = old_gen->object_space()->top(); | |
| 374 HeapWord* perm_top = perm_gen->object_space()->top(); | |
| 375 | |
| 376 // Release all previously held resources | |
| 377 gc_task_manager()->release_all_resources(); | |
| 378 | |
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379 // Set the number of GC threads to be used in this collection |
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380 gc_task_manager()->set_active_gang(); |
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381 gc_task_manager()->task_idle_workers(); |
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382 // Get the active number of workers here and use that value |
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383 // throughout the methods. |
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384 uint active_workers = gc_task_manager()->active_workers(); |
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385 heap->set_par_threads(active_workers); |
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386 |
| 0 | 387 PSPromotionManager::pre_scavenge(); |
| 388 | |
| 389 // We'll use the promotion manager again later. | |
| 390 PSPromotionManager* promotion_manager = PSPromotionManager::vm_thread_promotion_manager(); | |
| 391 { | |
| 392 // TraceTime("Roots"); | |
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393 ParallelScavengeHeap::ParStrongRootsScope psrs; |
| 0 | 394 |
| 395 GCTaskQueue* q = GCTaskQueue::create(); | |
| 396 | |
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397 uint stripe_total = active_workers; |
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398 for(uint i=0; i < stripe_total; i++) { |
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399 q->enqueue(new OldToYoungRootsTask(old_gen, old_top, i, stripe_total)); |
| 0 | 400 } |
| 401 | |
| 402 q->enqueue(new SerialOldToYoungRootsTask(perm_gen, perm_top)); | |
| 403 | |
| 404 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::universe)); | |
| 405 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jni_handles)); | |
| 406 // We scan the thread roots in parallel | |
| 407 Threads::create_thread_roots_tasks(q); | |
| 408 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::object_synchronizer)); | |
| 409 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::flat_profiler)); | |
| 410 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::management)); | |
| 411 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::system_dictionary)); | |
| 412 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::jvmti)); | |
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413 q->enqueue(new ScavengeRootsTask(ScavengeRootsTask::code_cache)); |
| 0 | 414 |
| 415 ParallelTaskTerminator terminator( | |
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416 active_workers, |
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417 (TaskQueueSetSuper*) promotion_manager->stack_array_depth()); |
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418 if (active_workers > 1) { |
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419 for (uint j = 0; j < active_workers; j++) { |
| 0 | 420 q->enqueue(new StealTask(&terminator)); |
| 421 } | |
| 422 } | |
| 423 | |
| 424 gc_task_manager()->execute_and_wait(q); | |
| 425 } | |
| 426 | |
| 427 scavenge_midpoint.update(); | |
| 428 | |
| 429 // Process reference objects discovered during scavenge | |
| 430 { | |
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431 reference_processor()->setup_policy(false); // not always_clear |
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432 reference_processor()->set_active_mt_degree(active_workers); |
| 0 | 433 PSKeepAliveClosure keep_alive(promotion_manager); |
| 434 PSEvacuateFollowersClosure evac_followers(promotion_manager); | |
| 435 if (reference_processor()->processing_is_mt()) { | |
| 436 PSRefProcTaskExecutor task_executor; | |
| 437 reference_processor()->process_discovered_references( | |
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438 &_is_alive_closure, &keep_alive, &evac_followers, &task_executor); |
| 0 | 439 } else { |
| 440 reference_processor()->process_discovered_references( | |
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441 &_is_alive_closure, &keep_alive, &evac_followers, NULL); |
| 0 | 442 } |
| 443 } | |
| 444 | |
| 445 // Enqueue reference objects discovered during scavenge. | |
| 446 if (reference_processor()->processing_is_mt()) { | |
| 447 PSRefProcTaskExecutor task_executor; | |
| 448 reference_processor()->enqueue_discovered_references(&task_executor); | |
| 449 } else { | |
| 450 reference_processor()->enqueue_discovered_references(NULL); | |
| 451 } | |
| 452 | |
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453 if (!JavaObjectsInPerm) { |
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454 // Unlink any dead interned Strings |
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455 StringTable::unlink(&_is_alive_closure); |
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456 // Process the remaining live ones |
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457 PSScavengeRootsClosure root_closure(promotion_manager); |
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458 StringTable::oops_do(&root_closure); |
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459 } |
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460 |
| 0 | 461 // Finally, flush the promotion_manager's labs, and deallocate its stacks. |
| 462 PSPromotionManager::post_scavenge(); | |
| 463 | |
| 464 promotion_failure_occurred = promotion_failed(); | |
| 465 if (promotion_failure_occurred) { | |
| 466 clean_up_failed_promotion(); | |
| 467 if (PrintGC) { | |
| 468 gclog_or_tty->print("--"); | |
| 469 } | |
| 470 } | |
| 471 | |
| 472 // Let the size policy know we're done. Note that we count promotion | |
| 473 // failure cleanup time as part of the collection (otherwise, we're | |
| 474 // implicitly saying it's mutator time). | |
| 475 size_policy->minor_collection_end(gc_cause); | |
| 476 | |
| 477 if (!promotion_failure_occurred) { | |
| 478 // Swap the survivor spaces. | |
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479 |
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480 |
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481 young_gen->eden_space()->clear(SpaceDecorator::Mangle); |
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482 young_gen->from_space()->clear(SpaceDecorator::Mangle); |
| 0 | 483 young_gen->swap_spaces(); |
| 484 | |
| 485 size_t survived = young_gen->from_space()->used_in_bytes(); | |
| 486 size_t promoted = old_gen->used_in_bytes() - old_gen_used_before; | |
| 487 size_policy->update_averages(_survivor_overflow, survived, promoted); | |
| 488 | |
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489 // A successful scavenge should restart the GC time limit count which is |
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490 // for full GC's. |
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491 size_policy->reset_gc_overhead_limit_count(); |
| 0 | 492 if (UseAdaptiveSizePolicy) { |
| 493 // Calculate the new survivor size and tenuring threshold | |
| 494 | |
| 495 if (PrintAdaptiveSizePolicy) { | |
| 496 gclog_or_tty->print("AdaptiveSizeStart: "); | |
| 497 gclog_or_tty->stamp(); | |
| 498 gclog_or_tty->print_cr(" collection: %d ", | |
| 499 heap->total_collections()); | |
| 500 | |
| 501 if (Verbose) { | |
| 502 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
| 503 " perm_gen_capacity: %d ", | |
| 504 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
| 505 perm_gen->capacity_in_bytes()); | |
| 506 } | |
| 507 } | |
| 508 | |
| 509 | |
| 510 if (UsePerfData) { | |
| 511 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 512 counters->update_old_eden_size( | |
| 513 size_policy->calculated_eden_size_in_bytes()); | |
| 514 counters->update_old_promo_size( | |
| 515 size_policy->calculated_promo_size_in_bytes()); | |
| 516 counters->update_old_capacity(old_gen->capacity_in_bytes()); | |
| 517 counters->update_young_capacity(young_gen->capacity_in_bytes()); | |
| 518 counters->update_survived(survived); | |
| 519 counters->update_promoted(promoted); | |
| 520 counters->update_survivor_overflowed(_survivor_overflow); | |
| 521 } | |
| 522 | |
| 523 size_t survivor_limit = | |
| 524 size_policy->max_survivor_size(young_gen->max_size()); | |
| 525 _tenuring_threshold = | |
| 526 size_policy->compute_survivor_space_size_and_threshold( | |
| 527 _survivor_overflow, | |
| 528 _tenuring_threshold, | |
| 529 survivor_limit); | |
| 530 | |
| 531 if (PrintTenuringDistribution) { | |
| 532 gclog_or_tty->cr(); | |
| 533 gclog_or_tty->print_cr("Desired survivor size %ld bytes, new threshold %d (max %d)", | |
| 534 size_policy->calculated_survivor_size_in_bytes(), | |
| 535 _tenuring_threshold, MaxTenuringThreshold); | |
| 536 } | |
| 537 | |
| 538 if (UsePerfData) { | |
| 539 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 540 counters->update_tenuring_threshold(_tenuring_threshold); | |
| 541 counters->update_survivor_size_counters(); | |
| 542 } | |
| 543 | |
| 544 // Do call at minor collections? | |
| 545 // Don't check if the size_policy is ready at this | |
| 546 // level. Let the size_policy check that internally. | |
| 547 if (UseAdaptiveSizePolicy && | |
| 548 UseAdaptiveGenerationSizePolicyAtMinorCollection && | |
| 549 ((gc_cause != GCCause::_java_lang_system_gc) || | |
| 550 UseAdaptiveSizePolicyWithSystemGC)) { | |
| 551 | |
| 552 // Calculate optimial free space amounts | |
| 553 assert(young_gen->max_size() > | |
| 554 young_gen->from_space()->capacity_in_bytes() + | |
| 555 young_gen->to_space()->capacity_in_bytes(), | |
| 556 "Sizes of space in young gen are out-of-bounds"); | |
| 557 size_t max_eden_size = young_gen->max_size() - | |
| 558 young_gen->from_space()->capacity_in_bytes() - | |
| 559 young_gen->to_space()->capacity_in_bytes(); | |
| 560 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
| 561 young_gen->eden_space()->used_in_bytes(), | |
| 562 old_gen->used_in_bytes(), | |
| 563 perm_gen->used_in_bytes(), | |
| 564 young_gen->eden_space()->capacity_in_bytes(), | |
| 565 old_gen->max_gen_size(), | |
| 566 max_eden_size, | |
| 567 false /* full gc*/, | |
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568 gc_cause, |
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569 heap->collector_policy()); |
| 0 | 570 |
| 571 } | |
| 572 // Resize the young generation at every collection | |
| 573 // even if new sizes have not been calculated. This is | |
| 574 // to allow resizes that may have been inhibited by the | |
| 575 // relative location of the "to" and "from" spaces. | |
| 576 | |
| 577 // Resizing the old gen at minor collects can cause increases | |
| 578 // that don't feed back to the generation sizing policy until | |
| 579 // a major collection. Don't resize the old gen here. | |
| 580 | |
| 581 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), | |
| 582 size_policy->calculated_survivor_size_in_bytes()); | |
| 583 | |
| 584 if (PrintAdaptiveSizePolicy) { | |
| 585 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
| 586 heap->total_collections()); | |
| 587 } | |
| 588 } | |
| 589 | |
| 590 // Update the structure of the eden. With NUMA-eden CPU hotplugging or offlining can | |
| 591 // cause the change of the heap layout. Make sure eden is reshaped if that's the case. | |
| 592 // Also update() will case adaptive NUMA chunk resizing. | |
| 593 assert(young_gen->eden_space()->is_empty(), "eden space should be empty now"); | |
| 594 young_gen->eden_space()->update(); | |
| 595 | |
| 596 heap->gc_policy_counters()->update_counters(); | |
| 597 | |
| 598 heap->resize_all_tlabs(); | |
| 599 | |
| 600 assert(young_gen->to_space()->is_empty(), "to space should be empty now"); | |
| 601 } | |
| 602 | |
| 603 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
| 604 | |
| 605 NOT_PRODUCT(reference_processor()->verify_no_references_recorded()); | |
| 606 | |
| 607 // Re-verify object start arrays | |
| 608 if (VerifyObjectStartArray && | |
| 609 VerifyAfterGC) { | |
| 610 old_gen->verify_object_start_array(); | |
| 611 perm_gen->verify_object_start_array(); | |
| 612 } | |
| 613 | |
| 614 // Verify all old -> young cards are now precise | |
| 615 if (VerifyRememberedSets) { | |
| 616 // Precise verification will give false positives. Until this is fixed, | |
| 617 // use imprecise verification. | |
| 618 // CardTableExtension::verify_all_young_refs_precise(); | |
| 619 CardTableExtension::verify_all_young_refs_imprecise(); | |
| 620 } | |
| 621 | |
| 622 if (TraceGen0Time) accumulated_time()->stop(); | |
| 623 | |
| 624 if (PrintGC) { | |
| 625 if (PrintGCDetails) { | |
| 626 // Don't print a GC timestamp here. This is after the GC so | |
| 627 // would be confusing. | |
| 628 young_gen->print_used_change(young_gen_used_before); | |
| 629 } | |
| 630 heap->print_heap_change(prev_used); | |
| 631 } | |
| 632 | |
| 633 // Track memory usage and detect low memory | |
| 634 MemoryService::track_memory_usage(); | |
| 635 heap->update_counters(); | |
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636 |
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637 gc_task_manager()->release_idle_workers(); |
| 0 | 638 } |
| 639 | |
| 640 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
| 641 HandleMark hm; // Discard invalid handles created during verification | |
| 642 gclog_or_tty->print(" VerifyAfterGC:"); | |
| 643 Universe::verify(false); | |
| 644 } | |
| 645 | |
| 646 if (PrintHeapAtGC) { | |
| 647 Universe::print_heap_after_gc(); | |
| 648 } | |
| 649 | |
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650 if (ZapUnusedHeapArea) { |
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651 young_gen->eden_space()->check_mangled_unused_area_complete(); |
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652 young_gen->from_space()->check_mangled_unused_area_complete(); |
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653 young_gen->to_space()->check_mangled_unused_area_complete(); |
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654 } |
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655 |
| 0 | 656 scavenge_exit.update(); |
| 657 | |
| 658 if (PrintGCTaskTimeStamps) { | |
| 659 tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " " INT64_FORMAT, | |
| 660 scavenge_entry.ticks(), scavenge_midpoint.ticks(), | |
| 661 scavenge_exit.ticks()); | |
| 662 gc_task_manager()->print_task_time_stamps(); | |
| 663 } | |
| 664 | |
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665 #ifdef TRACESPINNING |
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666 ParallelTaskTerminator::print_termination_counts(); |
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667 #endif |
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668 |
| 0 | 669 return !promotion_failure_occurred; |
| 670 } | |
| 671 | |
| 672 // This method iterates over all objects in the young generation, | |
| 673 // unforwarding markOops. It then restores any preserved mark oops, | |
| 674 // and clears the _preserved_mark_stack. | |
| 675 void PSScavenge::clean_up_failed_promotion() { | |
| 676 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 677 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 678 assert(promotion_failed(), "Sanity"); | |
| 679 | |
| 680 PSYoungGen* young_gen = heap->young_gen(); | |
| 681 | |
| 682 { | |
| 683 ResourceMark rm; | |
| 684 | |
| 685 // Unforward all pointers in the young gen. | |
| 686 PSPromotionFailedClosure unforward_closure; | |
| 687 young_gen->object_iterate(&unforward_closure); | |
| 688 | |
| 689 if (PrintGC && Verbose) { | |
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690 gclog_or_tty->print_cr("Restoring %d marks", _preserved_oop_stack.size()); |
| 0 | 691 } |
| 692 | |
| 693 // Restore any saved marks. | |
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694 while (!_preserved_oop_stack.is_empty()) { |
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695 oop obj = _preserved_oop_stack.pop(); |
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696 markOop mark = _preserved_mark_stack.pop(); |
| 0 | 697 obj->set_mark(mark); |
| 698 } | |
| 699 | |
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700 // Clear the preserved mark and oop stack caches. |
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701 _preserved_mark_stack.clear(true); |
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702 _preserved_oop_stack.clear(true); |
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703 _promotion_failed = false; |
| 0 | 704 } |
| 705 | |
| 706 // Reset the PromotionFailureALot counters. | |
| 707 NOT_PRODUCT(Universe::heap()->reset_promotion_should_fail();) | |
| 708 } | |
| 709 | |
| 710 // This method is called whenever an attempt to promote an object | |
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711 // fails. Some markOops will need preservation, some will not. Note |
| 0 | 712 // that the entire eden is traversed after a failed promotion, with |
| 713 // all forwarded headers replaced by the default markOop. This means | |
| 714 // it is not neccessary to preserve most markOops. | |
| 715 void PSScavenge::oop_promotion_failed(oop obj, markOop obj_mark) { | |
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716 _promotion_failed = true; |
| 0 | 717 if (obj_mark->must_be_preserved_for_promotion_failure(obj)) { |
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718 // Should use per-worker private stakcs hetre rather than |
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719 // locking a common pair of stacks. |
| 0 | 720 ThreadCritical tc; |
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721 _preserved_oop_stack.push(obj); |
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722 _preserved_mark_stack.push(obj_mark); |
| 0 | 723 } |
| 724 } | |
| 725 | |
| 726 bool PSScavenge::should_attempt_scavenge() { | |
| 727 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 728 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 729 PSGCAdaptivePolicyCounters* counters = heap->gc_policy_counters(); | |
| 730 | |
| 731 if (UsePerfData) { | |
| 732 counters->update_scavenge_skipped(not_skipped); | |
| 733 } | |
| 734 | |
| 735 PSYoungGen* young_gen = heap->young_gen(); | |
| 736 PSOldGen* old_gen = heap->old_gen(); | |
| 737 | |
| 738 if (!ScavengeWithObjectsInToSpace) { | |
| 739 // Do not attempt to promote unless to_space is empty | |
| 740 if (!young_gen->to_space()->is_empty()) { | |
| 741 _consecutive_skipped_scavenges++; | |
| 742 if (UsePerfData) { | |
| 743 counters->update_scavenge_skipped(to_space_not_empty); | |
| 744 } | |
| 745 return false; | |
| 746 } | |
| 747 } | |
| 748 | |
| 749 // Test to see if the scavenge will likely fail. | |
| 750 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
| 751 | |
| 752 // A similar test is done in the policy's should_full_GC(). If this is | |
| 753 // changed, decide if that test should also be changed. | |
| 754 size_t avg_promoted = (size_t) policy->padded_average_promoted_in_bytes(); | |
| 755 size_t promotion_estimate = MIN2(avg_promoted, young_gen->used_in_bytes()); | |
| 756 bool result = promotion_estimate < old_gen->free_in_bytes(); | |
| 757 | |
| 758 if (PrintGCDetails && Verbose) { | |
| 759 gclog_or_tty->print(result ? " do scavenge: " : " skip scavenge: "); | |
| 760 gclog_or_tty->print_cr(" average_promoted " SIZE_FORMAT | |
| 761 " padded_average_promoted " SIZE_FORMAT | |
| 762 " free in old gen " SIZE_FORMAT, | |
| 763 (size_t) policy->average_promoted_in_bytes(), | |
| 764 (size_t) policy->padded_average_promoted_in_bytes(), | |
| 765 old_gen->free_in_bytes()); | |
| 766 if (young_gen->used_in_bytes() < | |
| 767 (size_t) policy->padded_average_promoted_in_bytes()) { | |
| 768 gclog_or_tty->print_cr(" padded_promoted_average is greater" | |
| 769 " than maximum promotion = " SIZE_FORMAT, young_gen->used_in_bytes()); | |
| 770 } | |
| 771 } | |
| 772 | |
| 773 if (result) { | |
| 774 _consecutive_skipped_scavenges = 0; | |
| 775 } else { | |
| 776 _consecutive_skipped_scavenges++; | |
| 777 if (UsePerfData) { | |
| 778 counters->update_scavenge_skipped(promoted_too_large); | |
| 779 } | |
| 780 } | |
| 781 return result; | |
| 782 } | |
| 783 | |
| 784 // Used to add tasks | |
| 785 GCTaskManager* const PSScavenge::gc_task_manager() { | |
| 786 assert(ParallelScavengeHeap::gc_task_manager() != NULL, | |
| 787 "shouldn't return NULL"); | |
| 788 return ParallelScavengeHeap::gc_task_manager(); | |
| 789 } | |
| 790 | |
| 791 void PSScavenge::initialize() { | |
| 792 // Arguments must have been parsed | |
| 793 | |
| 794 if (AlwaysTenure) { | |
| 795 _tenuring_threshold = 0; | |
| 796 } else if (NeverTenure) { | |
| 797 _tenuring_threshold = markOopDesc::max_age + 1; | |
| 798 } else { | |
| 799 // We want to smooth out our startup times for the AdaptiveSizePolicy | |
| 800 _tenuring_threshold = (UseAdaptiveSizePolicy) ? InitialTenuringThreshold : | |
| 801 MaxTenuringThreshold; | |
| 802 } | |
| 803 | |
| 804 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 805 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 806 | |
| 807 PSYoungGen* young_gen = heap->young_gen(); | |
| 808 PSOldGen* old_gen = heap->old_gen(); | |
| 809 PSPermGen* perm_gen = heap->perm_gen(); | |
| 810 | |
| 811 // Set boundary between young_gen and old_gen | |
| 812 assert(perm_gen->reserved().end() <= old_gen->object_space()->bottom(), | |
| 813 "perm above old"); | |
| 814 assert(old_gen->reserved().end() <= young_gen->eden_space()->bottom(), | |
| 815 "old above young"); | |
| 816 _young_generation_boundary = young_gen->eden_space()->bottom(); | |
| 817 | |
| 818 // Initialize ref handling object for scavenging. | |
| 819 MemRegion mr = young_gen->reserved(); | |
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820 |
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821 _ref_processor = |
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822 new ReferenceProcessor(mr, // span |
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823 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing |
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824 (int) ParallelGCThreads, // mt processing degree |
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825 true, // mt discovery |
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826 (int) ParallelGCThreads, // mt discovery degree |
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827 true, // atomic_discovery |
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828 NULL, // header provides liveness info |
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829 false); // next field updates do not need write barrier |
| 0 | 830 |
| 831 // Cache the cardtable | |
| 832 BarrierSet* bs = Universe::heap()->barrier_set(); | |
| 833 assert(bs->kind() == BarrierSet::CardTableModRef, "Wrong barrier set kind"); | |
| 834 _card_table = (CardTableExtension*)bs; | |
| 835 | |
| 836 _counters = new CollectorCounters("PSScavenge", 0); | |
| 837 } |