Mon, 07 Jul 2014 10:12:40 +0200
8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com
duke@435 | 1 | /* |
drchase@6680 | 2 | * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "classfile/symbolTable.hpp" |
stefank@2314 | 27 | #include "classfile/systemDictionary.hpp" |
stefank@2314 | 28 | #include "code/codeCache.hpp" |
stefank@2314 | 29 | #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" |
stefank@2314 | 30 | #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" |
stefank@2314 | 31 | #include "gc_implementation/parallelScavenge/psMarkSweep.hpp" |
stefank@2314 | 32 | #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" |
stefank@2314 | 33 | #include "gc_implementation/parallelScavenge/psOldGen.hpp" |
stefank@2314 | 34 | #include "gc_implementation/parallelScavenge/psScavenge.hpp" |
stefank@2314 | 35 | #include "gc_implementation/parallelScavenge/psYoungGen.hpp" |
sla@5237 | 36 | #include "gc_implementation/shared/gcHeapSummary.hpp" |
sla@5237 | 37 | #include "gc_implementation/shared/gcTimer.hpp" |
sla@5237 | 38 | #include "gc_implementation/shared/gcTrace.hpp" |
sla@5237 | 39 | #include "gc_implementation/shared/gcTraceTime.hpp" |
stefank@2314 | 40 | #include "gc_implementation/shared/isGCActiveMark.hpp" |
coleenp@4037 | 41 | #include "gc_implementation/shared/markSweep.hpp" |
stefank@2314 | 42 | #include "gc_implementation/shared/spaceDecorator.hpp" |
stefank@2314 | 43 | #include "gc_interface/gcCause.hpp" |
stefank@2314 | 44 | #include "memory/gcLocker.inline.hpp" |
stefank@2314 | 45 | #include "memory/referencePolicy.hpp" |
stefank@2314 | 46 | #include "memory/referenceProcessor.hpp" |
stefank@2314 | 47 | #include "oops/oop.inline.hpp" |
stefank@2314 | 48 | #include "runtime/biasedLocking.hpp" |
stefank@2314 | 49 | #include "runtime/fprofiler.hpp" |
stefank@2314 | 50 | #include "runtime/safepoint.hpp" |
stefank@2314 | 51 | #include "runtime/vmThread.hpp" |
stefank@2314 | 52 | #include "services/management.hpp" |
stefank@2314 | 53 | #include "services/memoryService.hpp" |
stefank@2314 | 54 | #include "utilities/events.hpp" |
stefank@2314 | 55 | #include "utilities/stack.inline.hpp" |
duke@435 | 56 | |
drchase@6680 | 57 | PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
drchase@6680 | 58 | |
duke@435 | 59 | elapsedTimer PSMarkSweep::_accumulated_time; |
duke@435 | 60 | jlong PSMarkSweep::_time_of_last_gc = 0; |
duke@435 | 61 | CollectorCounters* PSMarkSweep::_counters = NULL; |
duke@435 | 62 | |
duke@435 | 63 | void PSMarkSweep::initialize() { |
duke@435 | 64 | MemRegion mr = Universe::heap()->reserved_region(); |
ysr@2651 | 65 | _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc |
jcoomes@809 | 66 | _counters = new CollectorCounters("PSMarkSweep", 1); |
duke@435 | 67 | } |
duke@435 | 68 | |
duke@435 | 69 | // This method contains all heap specific policy for invoking mark sweep. |
duke@435 | 70 | // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact |
duke@435 | 71 | // the heap. It will do nothing further. If we need to bail out for policy |
duke@435 | 72 | // reasons, scavenge before full gc, or any other specialized behavior, it |
duke@435 | 73 | // needs to be added here. |
duke@435 | 74 | // |
duke@435 | 75 | // Note that this method should only be called from the vm_thread while |
duke@435 | 76 | // at a safepoint! |
jmasa@1822 | 77 | // |
jmasa@1822 | 78 | // Note that the all_soft_refs_clear flag in the collector policy |
jmasa@1822 | 79 | // may be true because this method can be called without intervening |
jmasa@1822 | 80 | // activity. For example when the heap space is tight and full measure |
jmasa@1822 | 81 | // are being taken to free space. |
jmasa@1822 | 82 | |
duke@435 | 83 | void PSMarkSweep::invoke(bool maximum_heap_compaction) { |
duke@435 | 84 | assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
duke@435 | 85 | assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); |
duke@435 | 86 | assert(!Universe::heap()->is_gc_active(), "not reentrant"); |
duke@435 | 87 | |
duke@435 | 88 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 89 | GCCause::Cause gc_cause = heap->gc_cause(); |
duke@435 | 90 | PSAdaptiveSizePolicy* policy = heap->size_policy(); |
jmasa@1822 | 91 | IsGCActiveMark mark; |
duke@435 | 92 | |
jmasa@1822 | 93 | if (ScavengeBeforeFullGC) { |
jmasa@1822 | 94 | PSScavenge::invoke_no_policy(); |
jmasa@1822 | 95 | } |
duke@435 | 96 | |
jmasa@1822 | 97 | const bool clear_all_soft_refs = |
jmasa@1822 | 98 | heap->collector_policy()->should_clear_all_soft_refs(); |
duke@435 | 99 | |
tschatzl@5119 | 100 | uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount; |
tschatzl@5119 | 101 | UIntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); |
jmasa@1822 | 102 | PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); |
duke@435 | 103 | } |
duke@435 | 104 | |
duke@435 | 105 | // This method contains no policy. You should probably |
duke@435 | 106 | // be calling invoke() instead. |
jcoomes@3540 | 107 | bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { |
duke@435 | 108 | assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
duke@435 | 109 | assert(ref_processor() != NULL, "Sanity"); |
duke@435 | 110 | |
duke@435 | 111 | if (GC_locker::check_active_before_gc()) { |
jcoomes@3540 | 112 | return false; |
duke@435 | 113 | } |
duke@435 | 114 | |
duke@435 | 115 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
sla@5237 | 116 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 117 | GCCause::Cause gc_cause = heap->gc_cause(); |
sla@5237 | 118 | |
mgronlun@6131 | 119 | _gc_timer->register_gc_start(); |
sla@5237 | 120 | _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start()); |
sla@5237 | 121 | |
duke@435 | 122 | PSAdaptiveSizePolicy* size_policy = heap->size_policy(); |
duke@435 | 123 | |
jmasa@1822 | 124 | // The scope of casr should end after code that can change |
jmasa@1822 | 125 | // CollectorPolicy::_should_clear_all_soft_refs. |
jmasa@1822 | 126 | ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); |
jmasa@1822 | 127 | |
duke@435 | 128 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 129 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 130 | |
duke@435 | 131 | // Increment the invocation count |
duke@435 | 132 | heap->increment_total_collections(true /* full */); |
duke@435 | 133 | |
jmasa@698 | 134 | // Save information needed to minimize mangling |
jmasa@698 | 135 | heap->record_gen_tops_before_GC(); |
jmasa@698 | 136 | |
duke@435 | 137 | // We need to track unique mark sweep invocations as well. |
duke@435 | 138 | _total_invocations++; |
duke@435 | 139 | |
duke@435 | 140 | AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); |
duke@435 | 141 | |
never@3499 | 142 | heap->print_heap_before_gc(); |
sla@5237 | 143 | heap->trace_heap_before_gc(_gc_tracer); |
duke@435 | 144 | |
duke@435 | 145 | // Fill in TLABs |
duke@435 | 146 | heap->accumulate_statistics_all_tlabs(); |
duke@435 | 147 | heap->ensure_parsability(true); // retire TLABs |
duke@435 | 148 | |
duke@435 | 149 | if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 150 | HandleMark hm; // Discard invalid handles created during verification |
stefank@5018 | 151 | Universe::verify(" VerifyBeforeGC:"); |
duke@435 | 152 | } |
duke@435 | 153 | |
duke@435 | 154 | // Verify object start arrays |
duke@435 | 155 | if (VerifyObjectStartArray && |
duke@435 | 156 | VerifyBeforeGC) { |
duke@435 | 157 | old_gen->verify_object_start_array(); |
duke@435 | 158 | } |
duke@435 | 159 | |
sla@5237 | 160 | heap->pre_full_gc_dump(_gc_timer); |
ysr@1050 | 161 | |
duke@435 | 162 | // Filled in below to track the state of the young gen after the collection. |
duke@435 | 163 | bool eden_empty; |
duke@435 | 164 | bool survivors_empty; |
duke@435 | 165 | bool young_gen_empty; |
duke@435 | 166 | |
duke@435 | 167 | { |
duke@435 | 168 | HandleMark hm; |
brutisso@3767 | 169 | |
duke@435 | 170 | gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); |
duke@435 | 171 | TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); |
brutisso@6904 | 172 | GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer->gc_id()); |
duke@435 | 173 | TraceCollectorStats tcs(counters()); |
fparain@2888 | 174 | TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); |
duke@435 | 175 | |
duke@435 | 176 | if (TraceGen1Time) accumulated_time()->start(); |
duke@435 | 177 | |
duke@435 | 178 | // Let the size policy know we're starting |
duke@435 | 179 | size_policy->major_collection_begin(); |
duke@435 | 180 | |
duke@435 | 181 | CodeCache::gc_prologue(); |
duke@435 | 182 | Threads::gc_prologue(); |
duke@435 | 183 | BiasedLocking::preserve_marks(); |
duke@435 | 184 | |
duke@435 | 185 | // Capture heap size before collection for printing. |
duke@435 | 186 | size_t prev_used = heap->used(); |
duke@435 | 187 | |
coleenp@4037 | 188 | // Capture metadata size before collection for sizing. |
ehelin@6609 | 189 | size_t metadata_prev_used = MetaspaceAux::used_bytes(); |
duke@435 | 190 | |
duke@435 | 191 | // For PrintGCDetails |
duke@435 | 192 | size_t old_gen_prev_used = old_gen->used_in_bytes(); |
duke@435 | 193 | size_t young_gen_prev_used = young_gen->used_in_bytes(); |
duke@435 | 194 | |
duke@435 | 195 | allocate_stacks(); |
duke@435 | 196 | |
duke@435 | 197 | COMPILER2_PRESENT(DerivedPointerTable::clear()); |
duke@435 | 198 | |
johnc@3175 | 199 | ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/); |
ysr@892 | 200 | ref_processor()->setup_policy(clear_all_softrefs); |
duke@435 | 201 | |
duke@435 | 202 | mark_sweep_phase1(clear_all_softrefs); |
duke@435 | 203 | |
duke@435 | 204 | mark_sweep_phase2(); |
duke@435 | 205 | |
duke@435 | 206 | // Don't add any more derived pointers during phase3 |
duke@435 | 207 | COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); |
duke@435 | 208 | COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); |
duke@435 | 209 | |
duke@435 | 210 | mark_sweep_phase3(); |
duke@435 | 211 | |
duke@435 | 212 | mark_sweep_phase4(); |
duke@435 | 213 | |
duke@435 | 214 | restore_marks(); |
duke@435 | 215 | |
duke@435 | 216 | deallocate_stacks(); |
duke@435 | 217 | |
jmasa@698 | 218 | if (ZapUnusedHeapArea) { |
jmasa@698 | 219 | // Do a complete mangle (top to end) because the usage for |
jmasa@698 | 220 | // scratch does not maintain a top pointer. |
jmasa@698 | 221 | young_gen->to_space()->mangle_unused_area_complete(); |
jmasa@698 | 222 | } |
jmasa@698 | 223 | |
duke@435 | 224 | eden_empty = young_gen->eden_space()->is_empty(); |
duke@435 | 225 | if (!eden_empty) { |
duke@435 | 226 | eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); |
duke@435 | 227 | } |
duke@435 | 228 | |
duke@435 | 229 | // Update heap occupancy information which is used as |
duke@435 | 230 | // input to soft ref clearing policy at the next gc. |
duke@435 | 231 | Universe::update_heap_info_at_gc(); |
duke@435 | 232 | |
duke@435 | 233 | survivors_empty = young_gen->from_space()->is_empty() && |
jmasa@698 | 234 | young_gen->to_space()->is_empty(); |
duke@435 | 235 | young_gen_empty = eden_empty && survivors_empty; |
duke@435 | 236 | |
duke@435 | 237 | BarrierSet* bs = heap->barrier_set(); |
duke@435 | 238 | if (bs->is_a(BarrierSet::ModRef)) { |
duke@435 | 239 | ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; |
duke@435 | 240 | MemRegion old_mr = heap->old_gen()->reserved(); |
duke@435 | 241 | if (young_gen_empty) { |
coleenp@4037 | 242 | modBS->clear(MemRegion(old_mr.start(), old_mr.end())); |
duke@435 | 243 | } else { |
coleenp@4037 | 244 | modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); |
duke@435 | 245 | } |
duke@435 | 246 | } |
duke@435 | 247 | |
coleenp@4037 | 248 | // Delete metaspaces for unloaded class loaders and clean up loader_data graph |
coleenp@4037 | 249 | ClassLoaderDataGraph::purge(); |
jmasa@5015 | 250 | MetaspaceAux::verify_metrics(); |
coleenp@4037 | 251 | |
duke@435 | 252 | BiasedLocking::restore_marks(); |
duke@435 | 253 | Threads::gc_epilogue(); |
duke@435 | 254 | CodeCache::gc_epilogue(); |
kamg@2467 | 255 | JvmtiExport::gc_epilogue(); |
duke@435 | 256 | |
duke@435 | 257 | COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); |
duke@435 | 258 | |
duke@435 | 259 | ref_processor()->enqueue_discovered_references(NULL); |
duke@435 | 260 | |
duke@435 | 261 | // Update time of last GC |
duke@435 | 262 | reset_millis_since_last_gc(); |
duke@435 | 263 | |
duke@435 | 264 | // Let the size policy know we're done |
duke@435 | 265 | size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); |
duke@435 | 266 | |
duke@435 | 267 | if (UseAdaptiveSizePolicy) { |
duke@435 | 268 | |
duke@435 | 269 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 270 | gclog_or_tty->print("AdaptiveSizeStart: "); |
duke@435 | 271 | gclog_or_tty->stamp(); |
duke@435 | 272 | gclog_or_tty->print_cr(" collection: %d ", |
duke@435 | 273 | heap->total_collections()); |
duke@435 | 274 | if (Verbose) { |
coleenp@4037 | 275 | gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d", |
coleenp@4037 | 276 | old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); |
duke@435 | 277 | } |
duke@435 | 278 | } |
duke@435 | 279 | |
duke@435 | 280 | // Don't check if the size_policy is ready here. Let |
duke@435 | 281 | // the size_policy check that internally. |
duke@435 | 282 | if (UseAdaptiveGenerationSizePolicyAtMajorCollection && |
duke@435 | 283 | ((gc_cause != GCCause::_java_lang_system_gc) || |
duke@435 | 284 | UseAdaptiveSizePolicyWithSystemGC)) { |
duke@435 | 285 | // Calculate optimal free space amounts |
duke@435 | 286 | assert(young_gen->max_size() > |
duke@435 | 287 | young_gen->from_space()->capacity_in_bytes() + |
duke@435 | 288 | young_gen->to_space()->capacity_in_bytes(), |
duke@435 | 289 | "Sizes of space in young gen are out-of-bounds"); |
tamao@5120 | 290 | |
tamao@5120 | 291 | size_t young_live = young_gen->used_in_bytes(); |
tamao@5120 | 292 | size_t eden_live = young_gen->eden_space()->used_in_bytes(); |
tamao@5120 | 293 | size_t old_live = old_gen->used_in_bytes(); |
tamao@5120 | 294 | size_t cur_eden = young_gen->eden_space()->capacity_in_bytes(); |
tamao@5120 | 295 | size_t max_old_gen_size = old_gen->max_gen_size(); |
duke@435 | 296 | size_t max_eden_size = young_gen->max_size() - |
duke@435 | 297 | young_gen->from_space()->capacity_in_bytes() - |
duke@435 | 298 | young_gen->to_space()->capacity_in_bytes(); |
tamao@5120 | 299 | |
tamao@5120 | 300 | // Used for diagnostics |
tamao@5120 | 301 | size_policy->clear_generation_free_space_flags(); |
tamao@5120 | 302 | |
tamao@5192 | 303 | size_policy->compute_generations_free_space(young_live, |
tamao@5192 | 304 | eden_live, |
tamao@5192 | 305 | old_live, |
tamao@5192 | 306 | cur_eden, |
tamao@5192 | 307 | max_old_gen_size, |
tamao@5192 | 308 | max_eden_size, |
tamao@5192 | 309 | true /* full gc*/); |
tamao@5120 | 310 | |
tamao@5120 | 311 | size_policy->check_gc_overhead_limit(young_live, |
tamao@5120 | 312 | eden_live, |
tamao@5120 | 313 | max_old_gen_size, |
tamao@5120 | 314 | max_eden_size, |
tamao@5120 | 315 | true /* full gc*/, |
tamao@5120 | 316 | gc_cause, |
tamao@5120 | 317 | heap->collector_policy()); |
tamao@5120 | 318 | |
tamao@5120 | 319 | size_policy->decay_supplemental_growth(true /* full gc*/); |
duke@435 | 320 | |
duke@435 | 321 | heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); |
duke@435 | 322 | |
duke@435 | 323 | // Don't resize the young generation at an major collection. A |
duke@435 | 324 | // desired young generation size may have been calculated but |
duke@435 | 325 | // resizing the young generation complicates the code because the |
duke@435 | 326 | // resizing of the old generation may have moved the boundary |
duke@435 | 327 | // between the young generation and the old generation. Let the |
duke@435 | 328 | // young generation resizing happen at the minor collections. |
duke@435 | 329 | } |
duke@435 | 330 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 331 | gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", |
duke@435 | 332 | heap->total_collections()); |
duke@435 | 333 | } |
duke@435 | 334 | } |
duke@435 | 335 | |
duke@435 | 336 | if (UsePerfData) { |
duke@435 | 337 | heap->gc_policy_counters()->update_counters(); |
duke@435 | 338 | heap->gc_policy_counters()->update_old_capacity( |
duke@435 | 339 | old_gen->capacity_in_bytes()); |
duke@435 | 340 | heap->gc_policy_counters()->update_young_capacity( |
duke@435 | 341 | young_gen->capacity_in_bytes()); |
duke@435 | 342 | } |
duke@435 | 343 | |
duke@435 | 344 | heap->resize_all_tlabs(); |
duke@435 | 345 | |
coleenp@4037 | 346 | // We collected the heap, recalculate the metaspace capacity |
coleenp@4037 | 347 | MetaspaceGC::compute_new_size(); |
duke@435 | 348 | |
duke@435 | 349 | if (TraceGen1Time) accumulated_time()->stop(); |
duke@435 | 350 | |
duke@435 | 351 | if (PrintGC) { |
duke@435 | 352 | if (PrintGCDetails) { |
duke@435 | 353 | // Don't print a GC timestamp here. This is after the GC so |
duke@435 | 354 | // would be confusing. |
duke@435 | 355 | young_gen->print_used_change(young_gen_prev_used); |
duke@435 | 356 | old_gen->print_used_change(old_gen_prev_used); |
duke@435 | 357 | } |
duke@435 | 358 | heap->print_heap_change(prev_used); |
duke@435 | 359 | if (PrintGCDetails) { |
coleenp@4037 | 360 | MetaspaceAux::print_metaspace_change(metadata_prev_used); |
duke@435 | 361 | } |
duke@435 | 362 | } |
duke@435 | 363 | |
duke@435 | 364 | // Track memory usage and detect low memory |
duke@435 | 365 | MemoryService::track_memory_usage(); |
duke@435 | 366 | heap->update_counters(); |
duke@435 | 367 | } |
duke@435 | 368 | |
duke@435 | 369 | if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 370 | HandleMark hm; // Discard invalid handles created during verification |
stefank@5018 | 371 | Universe::verify(" VerifyAfterGC:"); |
duke@435 | 372 | } |
duke@435 | 373 | |
duke@435 | 374 | // Re-verify object start arrays |
duke@435 | 375 | if (VerifyObjectStartArray && |
duke@435 | 376 | VerifyAfterGC) { |
duke@435 | 377 | old_gen->verify_object_start_array(); |
duke@435 | 378 | } |
duke@435 | 379 | |
jmasa@698 | 380 | if (ZapUnusedHeapArea) { |
jmasa@698 | 381 | old_gen->object_space()->check_mangled_unused_area_complete(); |
jmasa@698 | 382 | } |
jmasa@698 | 383 | |
duke@435 | 384 | NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
duke@435 | 385 | |
never@3499 | 386 | heap->print_heap_after_gc(); |
sla@5237 | 387 | heap->trace_heap_after_gc(_gc_tracer); |
jmasa@981 | 388 | |
sla@5237 | 389 | heap->post_full_gc_dump(_gc_timer); |
ysr@1050 | 390 | |
jmasa@981 | 391 | #ifdef TRACESPINNING |
jmasa@981 | 392 | ParallelTaskTerminator::print_termination_counts(); |
jmasa@981 | 393 | #endif |
jcoomes@3540 | 394 | |
mgronlun@6131 | 395 | _gc_timer->register_gc_end(); |
sla@5237 | 396 | |
sla@5237 | 397 | _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions()); |
sla@5237 | 398 | |
jcoomes@3540 | 399 | return true; |
duke@435 | 400 | } |
duke@435 | 401 | |
duke@435 | 402 | bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, |
duke@435 | 403 | PSYoungGen* young_gen, |
duke@435 | 404 | PSOldGen* old_gen) { |
duke@435 | 405 | MutableSpace* const eden_space = young_gen->eden_space(); |
duke@435 | 406 | assert(!eden_space->is_empty(), "eden must be non-empty"); |
duke@435 | 407 | assert(young_gen->virtual_space()->alignment() == |
duke@435 | 408 | old_gen->virtual_space()->alignment(), "alignments do not match"); |
duke@435 | 409 | |
duke@435 | 410 | if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { |
duke@435 | 411 | return false; |
duke@435 | 412 | } |
duke@435 | 413 | |
duke@435 | 414 | // Both generations must be completely committed. |
duke@435 | 415 | if (young_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 416 | return false; |
duke@435 | 417 | } |
duke@435 | 418 | if (old_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 419 | return false; |
duke@435 | 420 | } |
duke@435 | 421 | |
duke@435 | 422 | // Figure out how much to take from eden. Include the average amount promoted |
duke@435 | 423 | // in the total; otherwise the next young gen GC will simply bail out to a |
duke@435 | 424 | // full GC. |
duke@435 | 425 | const size_t alignment = old_gen->virtual_space()->alignment(); |
duke@435 | 426 | const size_t eden_used = eden_space->used_in_bytes(); |
jcoomes@916 | 427 | const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
duke@435 | 428 | const size_t absorb_size = align_size_up(eden_used + promoted, alignment); |
duke@435 | 429 | const size_t eden_capacity = eden_space->capacity_in_bytes(); |
duke@435 | 430 | |
duke@435 | 431 | if (absorb_size >= eden_capacity) { |
duke@435 | 432 | return false; // Must leave some space in eden. |
duke@435 | 433 | } |
duke@435 | 434 | |
duke@435 | 435 | const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; |
duke@435 | 436 | if (new_young_size < young_gen->min_gen_size()) { |
duke@435 | 437 | return false; // Respect young gen minimum size. |
duke@435 | 438 | } |
duke@435 | 439 | |
duke@435 | 440 | if (TraceAdaptiveGCBoundary && Verbose) { |
duke@435 | 441 | gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " |
duke@435 | 442 | "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " |
duke@435 | 443 | "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " |
duke@435 | 444 | "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", |
duke@435 | 445 | absorb_size / K, |
duke@435 | 446 | eden_capacity / K, (eden_capacity - absorb_size) / K, |
duke@435 | 447 | young_gen->from_space()->used_in_bytes() / K, |
duke@435 | 448 | young_gen->to_space()->used_in_bytes() / K, |
duke@435 | 449 | young_gen->capacity_in_bytes() / K, new_young_size / K); |
duke@435 | 450 | } |
duke@435 | 451 | |
duke@435 | 452 | // Fill the unused part of the old gen. |
duke@435 | 453 | MutableSpace* const old_space = old_gen->object_space(); |
jcoomes@916 | 454 | HeapWord* const unused_start = old_space->top(); |
jcoomes@916 | 455 | size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
duke@435 | 456 | |
jcoomes@916 | 457 | if (unused_words > 0) { |
jcoomes@916 | 458 | if (unused_words < CollectedHeap::min_fill_size()) { |
jcoomes@916 | 459 | return false; // If the old gen cannot be filled, must give up. |
jcoomes@916 | 460 | } |
jcoomes@916 | 461 | CollectedHeap::fill_with_objects(unused_start, unused_words); |
duke@435 | 462 | } |
duke@435 | 463 | |
duke@435 | 464 | // Take the live data from eden and set both top and end in the old gen to |
duke@435 | 465 | // eden top. (Need to set end because reset_after_change() mangles the region |
duke@435 | 466 | // from end to virtual_space->high() in debug builds). |
duke@435 | 467 | HeapWord* const new_top = eden_space->top(); |
duke@435 | 468 | old_gen->virtual_space()->expand_into(young_gen->virtual_space(), |
duke@435 | 469 | absorb_size); |
duke@435 | 470 | young_gen->reset_after_change(); |
duke@435 | 471 | old_space->set_top(new_top); |
duke@435 | 472 | old_space->set_end(new_top); |
duke@435 | 473 | old_gen->reset_after_change(); |
duke@435 | 474 | |
duke@435 | 475 | // Update the object start array for the filler object and the data from eden. |
duke@435 | 476 | ObjectStartArray* const start_array = old_gen->start_array(); |
jcoomes@916 | 477 | for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
jcoomes@916 | 478 | start_array->allocate_block(p); |
duke@435 | 479 | } |
duke@435 | 480 | |
duke@435 | 481 | // Could update the promoted average here, but it is not typically updated at |
duke@435 | 482 | // full GCs and the value to use is unclear. Something like |
duke@435 | 483 | // |
duke@435 | 484 | // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. |
duke@435 | 485 | |
duke@435 | 486 | size_policy->set_bytes_absorbed_from_eden(absorb_size); |
duke@435 | 487 | return true; |
duke@435 | 488 | } |
duke@435 | 489 | |
duke@435 | 490 | void PSMarkSweep::allocate_stacks() { |
duke@435 | 491 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 492 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 493 | |
duke@435 | 494 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 495 | |
duke@435 | 496 | MutableSpace* to_space = young_gen->to_space(); |
duke@435 | 497 | _preserved_marks = (PreservedMark*)to_space->top(); |
duke@435 | 498 | _preserved_count = 0; |
duke@435 | 499 | |
duke@435 | 500 | // We want to calculate the size in bytes first. |
duke@435 | 501 | _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); |
duke@435 | 502 | // Now divide by the size of a PreservedMark |
duke@435 | 503 | _preserved_count_max /= sizeof(PreservedMark); |
duke@435 | 504 | } |
duke@435 | 505 | |
duke@435 | 506 | |
duke@435 | 507 | void PSMarkSweep::deallocate_stacks() { |
jcoomes@2191 | 508 | _preserved_mark_stack.clear(true); |
jcoomes@2191 | 509 | _preserved_oop_stack.clear(true); |
jcoomes@2191 | 510 | _marking_stack.clear(); |
jcoomes@2191 | 511 | _objarray_stack.clear(true); |
duke@435 | 512 | } |
duke@435 | 513 | |
duke@435 | 514 | void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { |
duke@435 | 515 | // Recursively traverse all live objects and mark them |
brutisso@6904 | 516 | GCTraceTime tm("phase 1", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); |
duke@435 | 517 | trace(" 1"); |
duke@435 | 518 | |
duke@435 | 519 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 520 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 521 | |
coleenp@4037 | 522 | // Need to clear claim bits before the tracing starts. |
coleenp@4037 | 523 | ClassLoaderDataGraph::clear_claimed_marks(); |
coleenp@4037 | 524 | |
duke@435 | 525 | // General strong roots. |
jrose@1424 | 526 | { |
jrose@1424 | 527 | ParallelScavengeHeap::ParStrongRootsScope psrs; |
jrose@1424 | 528 | Universe::oops_do(mark_and_push_closure()); |
jrose@1424 | 529 | JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles |
stefank@4298 | 530 | CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure()); |
stefank@6992 | 531 | MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations); |
stefank@4298 | 532 | Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob); |
jrose@1424 | 533 | ObjectSynchronizer::oops_do(mark_and_push_closure()); |
jrose@1424 | 534 | FlatProfiler::oops_do(mark_and_push_closure()); |
jrose@1424 | 535 | Management::oops_do(mark_and_push_closure()); |
jrose@1424 | 536 | JvmtiExport::oops_do(mark_and_push_closure()); |
jrose@1424 | 537 | SystemDictionary::always_strong_oops_do(mark_and_push_closure()); |
stefank@6992 | 538 | ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure()); |
jrose@1424 | 539 | // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. |
jrose@1424 | 540 | //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); |
jrose@1424 | 541 | } |
duke@435 | 542 | |
duke@435 | 543 | // Flush marking stack. |
duke@435 | 544 | follow_stack(); |
duke@435 | 545 | |
duke@435 | 546 | // Process reference objects found during marking |
duke@435 | 547 | { |
ysr@892 | 548 | ref_processor()->setup_policy(clear_all_softrefs); |
sla@5237 | 549 | const ReferenceProcessorStats& stats = |
sla@5237 | 550 | ref_processor()->process_discovered_references( |
brutisso@6904 | 551 | is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer, _gc_tracer->gc_id()); |
sla@5237 | 552 | gc_tracer()->report_gc_reference_stats(stats); |
duke@435 | 553 | } |
duke@435 | 554 | |
stefank@5020 | 555 | // This is the point where the entire marking should have completed. |
stefank@5020 | 556 | assert(_marking_stack.is_empty(), "Marking should have completed"); |
stefank@5020 | 557 | |
stefank@5020 | 558 | // Unload classes and purge the SystemDictionary. |
duke@435 | 559 | bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); |
duke@435 | 560 | |
stefank@5020 | 561 | // Unload nmethods. |
brutisso@4098 | 562 | CodeCache::do_unloading(is_alive_closure(), purged_class); |
duke@435 | 563 | |
stefank@5020 | 564 | // Prune dead klasses from subklass/sibling/implementor lists. |
stefank@5020 | 565 | Klass::clean_weak_klass_links(is_alive_closure()); |
ysr@1376 | 566 | |
stefank@5020 | 567 | // Delete entries for dead interned strings. |
duke@435 | 568 | StringTable::unlink(is_alive_closure()); |
stefank@5020 | 569 | |
coleenp@2497 | 570 | // Clean up unreferenced symbols in symbol table. |
coleenp@2497 | 571 | SymbolTable::unlink(); |
sla@5237 | 572 | _gc_tracer->report_object_count_after_gc(is_alive_closure()); |
duke@435 | 573 | } |
duke@435 | 574 | |
duke@435 | 575 | |
duke@435 | 576 | void PSMarkSweep::mark_sweep_phase2() { |
brutisso@6904 | 577 | GCTraceTime tm("phase 2", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); |
duke@435 | 578 | trace("2"); |
duke@435 | 579 | |
duke@435 | 580 | // Now all live objects are marked, compute the new object addresses. |
duke@435 | 581 | |
duke@435 | 582 | // It is not required that we traverse spaces in the same order in |
duke@435 | 583 | // phase2, phase3 and phase4, but the ValidateMarkSweep live oops |
duke@435 | 584 | // tracking expects us to do so. See comment under phase4. |
duke@435 | 585 | |
duke@435 | 586 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 587 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 588 | |
duke@435 | 589 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 590 | |
duke@435 | 591 | // Begin compacting into the old gen |
duke@435 | 592 | PSMarkSweepDecorator::set_destination_decorator_tenured(); |
duke@435 | 593 | |
duke@435 | 594 | // This will also compact the young gen spaces. |
duke@435 | 595 | old_gen->precompact(); |
duke@435 | 596 | } |
duke@435 | 597 | |
duke@435 | 598 | // This should be moved to the shared markSweep code! |
duke@435 | 599 | class PSAlwaysTrueClosure: public BoolObjectClosure { |
duke@435 | 600 | public: |
duke@435 | 601 | bool do_object_b(oop p) { return true; } |
duke@435 | 602 | }; |
duke@435 | 603 | static PSAlwaysTrueClosure always_true; |
duke@435 | 604 | |
duke@435 | 605 | void PSMarkSweep::mark_sweep_phase3() { |
duke@435 | 606 | // Adjust the pointers to reflect the new locations |
brutisso@6904 | 607 | GCTraceTime tm("phase 3", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); |
duke@435 | 608 | trace("3"); |
duke@435 | 609 | |
duke@435 | 610 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 611 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 612 | |
duke@435 | 613 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 614 | PSOldGen* old_gen = heap->old_gen(); |
coleenp@4037 | 615 | |
coleenp@4037 | 616 | // Need to clear claim bits before the tracing starts. |
coleenp@4037 | 617 | ClassLoaderDataGraph::clear_claimed_marks(); |
duke@435 | 618 | |
duke@435 | 619 | // General strong roots. |
stefank@5011 | 620 | Universe::oops_do(adjust_pointer_closure()); |
stefank@5011 | 621 | JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles |
stefank@5011 | 622 | CLDToOopClosure adjust_from_cld(adjust_pointer_closure()); |
stefank@5011 | 623 | Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL); |
stefank@5011 | 624 | ObjectSynchronizer::oops_do(adjust_pointer_closure()); |
stefank@5011 | 625 | FlatProfiler::oops_do(adjust_pointer_closure()); |
stefank@5011 | 626 | Management::oops_do(adjust_pointer_closure()); |
stefank@5011 | 627 | JvmtiExport::oops_do(adjust_pointer_closure()); |
stefank@5011 | 628 | SystemDictionary::oops_do(adjust_pointer_closure()); |
stefank@6992 | 629 | ClassLoaderDataGraph::cld_do(adjust_cld_closure()); |
duke@435 | 630 | |
duke@435 | 631 | // Now adjust pointers in remaining weak roots. (All of which should |
duke@435 | 632 | // have been cleared if they pointed to non-surviving objects.) |
duke@435 | 633 | // Global (weak) JNI handles |
stefank@5011 | 634 | JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure()); |
duke@435 | 635 | |
stefank@6992 | 636 | CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations); |
stefank@6992 | 637 | CodeCache::blobs_do(&adjust_from_blobs); |
stefank@5011 | 638 | StringTable::oops_do(adjust_pointer_closure()); |
stefank@5011 | 639 | ref_processor()->weak_oops_do(adjust_pointer_closure()); |
stefank@5011 | 640 | PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure()); |
duke@435 | 641 | |
duke@435 | 642 | adjust_marks(); |
duke@435 | 643 | |
duke@435 | 644 | young_gen->adjust_pointers(); |
duke@435 | 645 | old_gen->adjust_pointers(); |
duke@435 | 646 | } |
duke@435 | 647 | |
duke@435 | 648 | void PSMarkSweep::mark_sweep_phase4() { |
duke@435 | 649 | EventMark m("4 compact heap"); |
brutisso@6904 | 650 | GCTraceTime tm("phase 4", PrintGCDetails && Verbose, true, _gc_timer, _gc_tracer->gc_id()); |
duke@435 | 651 | trace("4"); |
duke@435 | 652 | |
duke@435 | 653 | // All pointers are now adjusted, move objects accordingly |
duke@435 | 654 | |
duke@435 | 655 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 656 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 657 | |
duke@435 | 658 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 659 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 660 | |
duke@435 | 661 | old_gen->compact(); |
duke@435 | 662 | young_gen->compact(); |
duke@435 | 663 | } |
duke@435 | 664 | |
duke@435 | 665 | jlong PSMarkSweep::millis_since_last_gc() { |
johnc@3339 | 666 | // We need a monotonically non-deccreasing time in ms but |
johnc@3339 | 667 | // os::javaTimeMillis() does not guarantee monotonicity. |
johnc@3339 | 668 | jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
johnc@3339 | 669 | jlong ret_val = now - _time_of_last_gc; |
duke@435 | 670 | // XXX See note in genCollectedHeap::millis_since_last_gc(). |
duke@435 | 671 | if (ret_val < 0) { |
johnc@3339 | 672 | NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);) |
duke@435 | 673 | return 0; |
duke@435 | 674 | } |
duke@435 | 675 | return ret_val; |
duke@435 | 676 | } |
duke@435 | 677 | |
duke@435 | 678 | void PSMarkSweep::reset_millis_since_last_gc() { |
johnc@3339 | 679 | // We need a monotonically non-deccreasing time in ms but |
johnc@3339 | 680 | // os::javaTimeMillis() does not guarantee monotonicity. |
johnc@3339 | 681 | _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
duke@435 | 682 | } |