Mon, 19 Dec 2011 10:02:05 -0800
7117303: VM uses non-monotonic time source and complains that it is non-monotonic
Summary: Replaces calls to os::javaTimeMillis(), which does not (and cannot) guarantee monotonicity, in GC code to an equivalent expression that uses os::javaTimeNanos(). os::javaTimeNanos is guaranteed monotonically non-decreasing if the underlying platform provides a monotonic time source. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.
Reviewed-by: dholmes, ysr
duke@435 | 1 | /* |
ysr@2651 | 2 | * Copyright (c) 2001, 2011, 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/generationSizer.hpp" |
stefank@2314 | 30 | #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" |
stefank@2314 | 31 | #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" |
stefank@2314 | 32 | #include "gc_implementation/parallelScavenge/psMarkSweep.hpp" |
stefank@2314 | 33 | #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" |
stefank@2314 | 34 | #include "gc_implementation/parallelScavenge/psOldGen.hpp" |
stefank@2314 | 35 | #include "gc_implementation/parallelScavenge/psPermGen.hpp" |
stefank@2314 | 36 | #include "gc_implementation/parallelScavenge/psScavenge.hpp" |
stefank@2314 | 37 | #include "gc_implementation/parallelScavenge/psYoungGen.hpp" |
stefank@2314 | 38 | #include "gc_implementation/shared/isGCActiveMark.hpp" |
stefank@2314 | 39 | #include "gc_implementation/shared/spaceDecorator.hpp" |
stefank@2314 | 40 | #include "gc_interface/gcCause.hpp" |
stefank@2314 | 41 | #include "memory/gcLocker.inline.hpp" |
stefank@2314 | 42 | #include "memory/referencePolicy.hpp" |
stefank@2314 | 43 | #include "memory/referenceProcessor.hpp" |
stefank@2314 | 44 | #include "oops/oop.inline.hpp" |
stefank@2314 | 45 | #include "runtime/biasedLocking.hpp" |
stefank@2314 | 46 | #include "runtime/fprofiler.hpp" |
stefank@2314 | 47 | #include "runtime/safepoint.hpp" |
stefank@2314 | 48 | #include "runtime/vmThread.hpp" |
stefank@2314 | 49 | #include "services/management.hpp" |
stefank@2314 | 50 | #include "services/memoryService.hpp" |
stefank@2314 | 51 | #include "utilities/events.hpp" |
stefank@2314 | 52 | #include "utilities/stack.inline.hpp" |
duke@435 | 53 | |
duke@435 | 54 | elapsedTimer PSMarkSweep::_accumulated_time; |
duke@435 | 55 | unsigned int PSMarkSweep::_total_invocations = 0; |
duke@435 | 56 | jlong PSMarkSweep::_time_of_last_gc = 0; |
duke@435 | 57 | CollectorCounters* PSMarkSweep::_counters = NULL; |
duke@435 | 58 | |
duke@435 | 59 | void PSMarkSweep::initialize() { |
duke@435 | 60 | MemRegion mr = Universe::heap()->reserved_region(); |
ysr@2651 | 61 | _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc |
jcoomes@809 | 62 | _counters = new CollectorCounters("PSMarkSweep", 1); |
duke@435 | 63 | } |
duke@435 | 64 | |
duke@435 | 65 | // This method contains all heap specific policy for invoking mark sweep. |
duke@435 | 66 | // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact |
duke@435 | 67 | // the heap. It will do nothing further. If we need to bail out for policy |
duke@435 | 68 | // reasons, scavenge before full gc, or any other specialized behavior, it |
duke@435 | 69 | // needs to be added here. |
duke@435 | 70 | // |
duke@435 | 71 | // Note that this method should only be called from the vm_thread while |
duke@435 | 72 | // at a safepoint! |
jmasa@1822 | 73 | // |
jmasa@1822 | 74 | // Note that the all_soft_refs_clear flag in the collector policy |
jmasa@1822 | 75 | // may be true because this method can be called without intervening |
jmasa@1822 | 76 | // activity. For example when the heap space is tight and full measure |
jmasa@1822 | 77 | // are being taken to free space. |
jmasa@1822 | 78 | |
duke@435 | 79 | void PSMarkSweep::invoke(bool maximum_heap_compaction) { |
duke@435 | 80 | assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
duke@435 | 81 | assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); |
duke@435 | 82 | assert(!Universe::heap()->is_gc_active(), "not reentrant"); |
duke@435 | 83 | |
duke@435 | 84 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 85 | GCCause::Cause gc_cause = heap->gc_cause(); |
duke@435 | 86 | PSAdaptiveSizePolicy* policy = heap->size_policy(); |
jmasa@1822 | 87 | IsGCActiveMark mark; |
duke@435 | 88 | |
jmasa@1822 | 89 | if (ScavengeBeforeFullGC) { |
jmasa@1822 | 90 | PSScavenge::invoke_no_policy(); |
jmasa@1822 | 91 | } |
duke@435 | 92 | |
jmasa@1822 | 93 | const bool clear_all_soft_refs = |
jmasa@1822 | 94 | heap->collector_policy()->should_clear_all_soft_refs(); |
duke@435 | 95 | |
jmasa@1822 | 96 | int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; |
jmasa@1822 | 97 | IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); |
jmasa@1822 | 98 | PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); |
duke@435 | 99 | } |
duke@435 | 100 | |
duke@435 | 101 | // This method contains no policy. You should probably |
duke@435 | 102 | // be calling invoke() instead. |
duke@435 | 103 | void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { |
duke@435 | 104 | assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
duke@435 | 105 | assert(ref_processor() != NULL, "Sanity"); |
duke@435 | 106 | |
duke@435 | 107 | if (GC_locker::check_active_before_gc()) { |
duke@435 | 108 | return; |
duke@435 | 109 | } |
duke@435 | 110 | |
duke@435 | 111 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 112 | GCCause::Cause gc_cause = heap->gc_cause(); |
duke@435 | 113 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 114 | PSAdaptiveSizePolicy* size_policy = heap->size_policy(); |
duke@435 | 115 | |
jmasa@1822 | 116 | // The scope of casr should end after code that can change |
jmasa@1822 | 117 | // CollectorPolicy::_should_clear_all_soft_refs. |
jmasa@1822 | 118 | ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); |
jmasa@1822 | 119 | |
duke@435 | 120 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 121 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 122 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 123 | |
duke@435 | 124 | // Increment the invocation count |
duke@435 | 125 | heap->increment_total_collections(true /* full */); |
duke@435 | 126 | |
jmasa@698 | 127 | // Save information needed to minimize mangling |
jmasa@698 | 128 | heap->record_gen_tops_before_GC(); |
jmasa@698 | 129 | |
duke@435 | 130 | // We need to track unique mark sweep invocations as well. |
duke@435 | 131 | _total_invocations++; |
duke@435 | 132 | |
duke@435 | 133 | AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); |
duke@435 | 134 | |
duke@435 | 135 | if (PrintHeapAtGC) { |
duke@435 | 136 | Universe::print_heap_before_gc(); |
duke@435 | 137 | } |
duke@435 | 138 | |
duke@435 | 139 | // Fill in TLABs |
duke@435 | 140 | heap->accumulate_statistics_all_tlabs(); |
duke@435 | 141 | heap->ensure_parsability(true); // retire TLABs |
duke@435 | 142 | |
duke@435 | 143 | if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 144 | HandleMark hm; // Discard invalid handles created during verification |
duke@435 | 145 | gclog_or_tty->print(" VerifyBeforeGC:"); |
duke@435 | 146 | Universe::verify(true); |
duke@435 | 147 | } |
duke@435 | 148 | |
duke@435 | 149 | // Verify object start arrays |
duke@435 | 150 | if (VerifyObjectStartArray && |
duke@435 | 151 | VerifyBeforeGC) { |
duke@435 | 152 | old_gen->verify_object_start_array(); |
duke@435 | 153 | perm_gen->verify_object_start_array(); |
duke@435 | 154 | } |
duke@435 | 155 | |
ysr@1050 | 156 | heap->pre_full_gc_dump(); |
ysr@1050 | 157 | |
duke@435 | 158 | // Filled in below to track the state of the young gen after the collection. |
duke@435 | 159 | bool eden_empty; |
duke@435 | 160 | bool survivors_empty; |
duke@435 | 161 | bool young_gen_empty; |
duke@435 | 162 | |
duke@435 | 163 | { |
duke@435 | 164 | HandleMark hm; |
duke@435 | 165 | const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; |
duke@435 | 166 | // This is useful for debugging but don't change the output the |
duke@435 | 167 | // the customer sees. |
duke@435 | 168 | const char* gc_cause_str = "Full GC"; |
duke@435 | 169 | if (is_system_gc && PrintGCDetails) { |
duke@435 | 170 | gc_cause_str = "Full GC (System)"; |
duke@435 | 171 | } |
duke@435 | 172 | gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); |
duke@435 | 173 | TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); |
duke@435 | 174 | TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); |
duke@435 | 175 | TraceCollectorStats tcs(counters()); |
fparain@2888 | 176 | TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); |
duke@435 | 177 | |
duke@435 | 178 | if (TraceGen1Time) accumulated_time()->start(); |
duke@435 | 179 | |
duke@435 | 180 | // Let the size policy know we're starting |
duke@435 | 181 | size_policy->major_collection_begin(); |
duke@435 | 182 | |
duke@435 | 183 | // When collecting the permanent generation methodOops may be moving, |
duke@435 | 184 | // so we either have to flush all bcp data or convert it into bci. |
duke@435 | 185 | CodeCache::gc_prologue(); |
duke@435 | 186 | Threads::gc_prologue(); |
duke@435 | 187 | BiasedLocking::preserve_marks(); |
duke@435 | 188 | |
duke@435 | 189 | // Capture heap size before collection for printing. |
duke@435 | 190 | size_t prev_used = heap->used(); |
duke@435 | 191 | |
duke@435 | 192 | // Capture perm gen size before collection for sizing. |
duke@435 | 193 | size_t perm_gen_prev_used = perm_gen->used_in_bytes(); |
duke@435 | 194 | |
duke@435 | 195 | // For PrintGCDetails |
duke@435 | 196 | size_t old_gen_prev_used = old_gen->used_in_bytes(); |
duke@435 | 197 | size_t young_gen_prev_used = young_gen->used_in_bytes(); |
duke@435 | 198 | |
duke@435 | 199 | allocate_stacks(); |
duke@435 | 200 | |
duke@435 | 201 | COMPILER2_PRESENT(DerivedPointerTable::clear()); |
duke@435 | 202 | |
johnc@3175 | 203 | ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/); |
ysr@892 | 204 | ref_processor()->setup_policy(clear_all_softrefs); |
duke@435 | 205 | |
duke@435 | 206 | mark_sweep_phase1(clear_all_softrefs); |
duke@435 | 207 | |
duke@435 | 208 | mark_sweep_phase2(); |
duke@435 | 209 | |
duke@435 | 210 | // Don't add any more derived pointers during phase3 |
duke@435 | 211 | COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); |
duke@435 | 212 | COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); |
duke@435 | 213 | |
duke@435 | 214 | mark_sweep_phase3(); |
duke@435 | 215 | |
duke@435 | 216 | mark_sweep_phase4(); |
duke@435 | 217 | |
duke@435 | 218 | restore_marks(); |
duke@435 | 219 | |
duke@435 | 220 | deallocate_stacks(); |
duke@435 | 221 | |
jmasa@698 | 222 | if (ZapUnusedHeapArea) { |
jmasa@698 | 223 | // Do a complete mangle (top to end) because the usage for |
jmasa@698 | 224 | // scratch does not maintain a top pointer. |
jmasa@698 | 225 | young_gen->to_space()->mangle_unused_area_complete(); |
jmasa@698 | 226 | } |
jmasa@698 | 227 | |
duke@435 | 228 | eden_empty = young_gen->eden_space()->is_empty(); |
duke@435 | 229 | if (!eden_empty) { |
duke@435 | 230 | eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); |
duke@435 | 231 | } |
duke@435 | 232 | |
duke@435 | 233 | // Update heap occupancy information which is used as |
duke@435 | 234 | // input to soft ref clearing policy at the next gc. |
duke@435 | 235 | Universe::update_heap_info_at_gc(); |
duke@435 | 236 | |
duke@435 | 237 | survivors_empty = young_gen->from_space()->is_empty() && |
jmasa@698 | 238 | young_gen->to_space()->is_empty(); |
duke@435 | 239 | young_gen_empty = eden_empty && survivors_empty; |
duke@435 | 240 | |
duke@435 | 241 | BarrierSet* bs = heap->barrier_set(); |
duke@435 | 242 | if (bs->is_a(BarrierSet::ModRef)) { |
duke@435 | 243 | ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; |
duke@435 | 244 | MemRegion old_mr = heap->old_gen()->reserved(); |
duke@435 | 245 | MemRegion perm_mr = heap->perm_gen()->reserved(); |
duke@435 | 246 | assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); |
duke@435 | 247 | |
duke@435 | 248 | if (young_gen_empty) { |
duke@435 | 249 | modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); |
duke@435 | 250 | } else { |
duke@435 | 251 | modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); |
duke@435 | 252 | } |
duke@435 | 253 | } |
duke@435 | 254 | |
duke@435 | 255 | BiasedLocking::restore_marks(); |
duke@435 | 256 | Threads::gc_epilogue(); |
duke@435 | 257 | CodeCache::gc_epilogue(); |
kamg@2467 | 258 | JvmtiExport::gc_epilogue(); |
duke@435 | 259 | |
duke@435 | 260 | COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); |
duke@435 | 261 | |
duke@435 | 262 | ref_processor()->enqueue_discovered_references(NULL); |
duke@435 | 263 | |
duke@435 | 264 | // Update time of last GC |
duke@435 | 265 | reset_millis_since_last_gc(); |
duke@435 | 266 | |
duke@435 | 267 | // Let the size policy know we're done |
duke@435 | 268 | size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); |
duke@435 | 269 | |
duke@435 | 270 | if (UseAdaptiveSizePolicy) { |
duke@435 | 271 | |
duke@435 | 272 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 273 | gclog_or_tty->print("AdaptiveSizeStart: "); |
duke@435 | 274 | gclog_or_tty->stamp(); |
duke@435 | 275 | gclog_or_tty->print_cr(" collection: %d ", |
duke@435 | 276 | heap->total_collections()); |
duke@435 | 277 | if (Verbose) { |
duke@435 | 278 | gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" |
duke@435 | 279 | " perm_gen_capacity: %d ", |
duke@435 | 280 | old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), |
duke@435 | 281 | perm_gen->capacity_in_bytes()); |
duke@435 | 282 | } |
duke@435 | 283 | } |
duke@435 | 284 | |
duke@435 | 285 | // Don't check if the size_policy is ready here. Let |
duke@435 | 286 | // the size_policy check that internally. |
duke@435 | 287 | if (UseAdaptiveGenerationSizePolicyAtMajorCollection && |
duke@435 | 288 | ((gc_cause != GCCause::_java_lang_system_gc) || |
duke@435 | 289 | UseAdaptiveSizePolicyWithSystemGC)) { |
duke@435 | 290 | // Calculate optimal free space amounts |
duke@435 | 291 | assert(young_gen->max_size() > |
duke@435 | 292 | young_gen->from_space()->capacity_in_bytes() + |
duke@435 | 293 | young_gen->to_space()->capacity_in_bytes(), |
duke@435 | 294 | "Sizes of space in young gen are out-of-bounds"); |
duke@435 | 295 | size_t max_eden_size = young_gen->max_size() - |
duke@435 | 296 | young_gen->from_space()->capacity_in_bytes() - |
duke@435 | 297 | young_gen->to_space()->capacity_in_bytes(); |
duke@435 | 298 | size_policy->compute_generation_free_space(young_gen->used_in_bytes(), |
duke@435 | 299 | young_gen->eden_space()->used_in_bytes(), |
duke@435 | 300 | old_gen->used_in_bytes(), |
duke@435 | 301 | perm_gen->used_in_bytes(), |
duke@435 | 302 | young_gen->eden_space()->capacity_in_bytes(), |
duke@435 | 303 | old_gen->max_gen_size(), |
duke@435 | 304 | max_eden_size, |
duke@435 | 305 | true /* full gc*/, |
jmasa@1822 | 306 | gc_cause, |
jmasa@1822 | 307 | heap->collector_policy()); |
duke@435 | 308 | |
duke@435 | 309 | heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); |
duke@435 | 310 | |
duke@435 | 311 | // Don't resize the young generation at an major collection. A |
duke@435 | 312 | // desired young generation size may have been calculated but |
duke@435 | 313 | // resizing the young generation complicates the code because the |
duke@435 | 314 | // resizing of the old generation may have moved the boundary |
duke@435 | 315 | // between the young generation and the old generation. Let the |
duke@435 | 316 | // young generation resizing happen at the minor collections. |
duke@435 | 317 | } |
duke@435 | 318 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 319 | gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", |
duke@435 | 320 | heap->total_collections()); |
duke@435 | 321 | } |
duke@435 | 322 | } |
duke@435 | 323 | |
duke@435 | 324 | if (UsePerfData) { |
duke@435 | 325 | heap->gc_policy_counters()->update_counters(); |
duke@435 | 326 | heap->gc_policy_counters()->update_old_capacity( |
duke@435 | 327 | old_gen->capacity_in_bytes()); |
duke@435 | 328 | heap->gc_policy_counters()->update_young_capacity( |
duke@435 | 329 | young_gen->capacity_in_bytes()); |
duke@435 | 330 | } |
duke@435 | 331 | |
duke@435 | 332 | heap->resize_all_tlabs(); |
duke@435 | 333 | |
duke@435 | 334 | // We collected the perm gen, so we'll resize it here. |
duke@435 | 335 | perm_gen->compute_new_size(perm_gen_prev_used); |
duke@435 | 336 | |
duke@435 | 337 | if (TraceGen1Time) accumulated_time()->stop(); |
duke@435 | 338 | |
duke@435 | 339 | if (PrintGC) { |
duke@435 | 340 | if (PrintGCDetails) { |
duke@435 | 341 | // Don't print a GC timestamp here. This is after the GC so |
duke@435 | 342 | // would be confusing. |
duke@435 | 343 | young_gen->print_used_change(young_gen_prev_used); |
duke@435 | 344 | old_gen->print_used_change(old_gen_prev_used); |
duke@435 | 345 | } |
duke@435 | 346 | heap->print_heap_change(prev_used); |
duke@435 | 347 | // Do perm gen after heap becase prev_used does |
duke@435 | 348 | // not include the perm gen (done this way in the other |
duke@435 | 349 | // collectors). |
duke@435 | 350 | if (PrintGCDetails) { |
duke@435 | 351 | perm_gen->print_used_change(perm_gen_prev_used); |
duke@435 | 352 | } |
duke@435 | 353 | } |
duke@435 | 354 | |
duke@435 | 355 | // Track memory usage and detect low memory |
duke@435 | 356 | MemoryService::track_memory_usage(); |
duke@435 | 357 | heap->update_counters(); |
duke@435 | 358 | } |
duke@435 | 359 | |
duke@435 | 360 | if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 361 | HandleMark hm; // Discard invalid handles created during verification |
duke@435 | 362 | gclog_or_tty->print(" VerifyAfterGC:"); |
duke@435 | 363 | Universe::verify(false); |
duke@435 | 364 | } |
duke@435 | 365 | |
duke@435 | 366 | // Re-verify object start arrays |
duke@435 | 367 | if (VerifyObjectStartArray && |
duke@435 | 368 | VerifyAfterGC) { |
duke@435 | 369 | old_gen->verify_object_start_array(); |
duke@435 | 370 | perm_gen->verify_object_start_array(); |
duke@435 | 371 | } |
duke@435 | 372 | |
jmasa@698 | 373 | if (ZapUnusedHeapArea) { |
jmasa@698 | 374 | old_gen->object_space()->check_mangled_unused_area_complete(); |
jmasa@698 | 375 | perm_gen->object_space()->check_mangled_unused_area_complete(); |
jmasa@698 | 376 | } |
jmasa@698 | 377 | |
duke@435 | 378 | NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
duke@435 | 379 | |
duke@435 | 380 | if (PrintHeapAtGC) { |
duke@435 | 381 | Universe::print_heap_after_gc(); |
duke@435 | 382 | } |
jmasa@981 | 383 | |
ysr@1050 | 384 | heap->post_full_gc_dump(); |
ysr@1050 | 385 | |
jmasa@981 | 386 | #ifdef TRACESPINNING |
jmasa@981 | 387 | ParallelTaskTerminator::print_termination_counts(); |
jmasa@981 | 388 | #endif |
duke@435 | 389 | } |
duke@435 | 390 | |
duke@435 | 391 | bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, |
duke@435 | 392 | PSYoungGen* young_gen, |
duke@435 | 393 | PSOldGen* old_gen) { |
duke@435 | 394 | MutableSpace* const eden_space = young_gen->eden_space(); |
duke@435 | 395 | assert(!eden_space->is_empty(), "eden must be non-empty"); |
duke@435 | 396 | assert(young_gen->virtual_space()->alignment() == |
duke@435 | 397 | old_gen->virtual_space()->alignment(), "alignments do not match"); |
duke@435 | 398 | |
duke@435 | 399 | if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { |
duke@435 | 400 | return false; |
duke@435 | 401 | } |
duke@435 | 402 | |
duke@435 | 403 | // Both generations must be completely committed. |
duke@435 | 404 | if (young_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 405 | return false; |
duke@435 | 406 | } |
duke@435 | 407 | if (old_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 408 | return false; |
duke@435 | 409 | } |
duke@435 | 410 | |
duke@435 | 411 | // Figure out how much to take from eden. Include the average amount promoted |
duke@435 | 412 | // in the total; otherwise the next young gen GC will simply bail out to a |
duke@435 | 413 | // full GC. |
duke@435 | 414 | const size_t alignment = old_gen->virtual_space()->alignment(); |
duke@435 | 415 | const size_t eden_used = eden_space->used_in_bytes(); |
jcoomes@916 | 416 | const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
duke@435 | 417 | const size_t absorb_size = align_size_up(eden_used + promoted, alignment); |
duke@435 | 418 | const size_t eden_capacity = eden_space->capacity_in_bytes(); |
duke@435 | 419 | |
duke@435 | 420 | if (absorb_size >= eden_capacity) { |
duke@435 | 421 | return false; // Must leave some space in eden. |
duke@435 | 422 | } |
duke@435 | 423 | |
duke@435 | 424 | const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; |
duke@435 | 425 | if (new_young_size < young_gen->min_gen_size()) { |
duke@435 | 426 | return false; // Respect young gen minimum size. |
duke@435 | 427 | } |
duke@435 | 428 | |
duke@435 | 429 | if (TraceAdaptiveGCBoundary && Verbose) { |
duke@435 | 430 | gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " |
duke@435 | 431 | "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " |
duke@435 | 432 | "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " |
duke@435 | 433 | "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", |
duke@435 | 434 | absorb_size / K, |
duke@435 | 435 | eden_capacity / K, (eden_capacity - absorb_size) / K, |
duke@435 | 436 | young_gen->from_space()->used_in_bytes() / K, |
duke@435 | 437 | young_gen->to_space()->used_in_bytes() / K, |
duke@435 | 438 | young_gen->capacity_in_bytes() / K, new_young_size / K); |
duke@435 | 439 | } |
duke@435 | 440 | |
duke@435 | 441 | // Fill the unused part of the old gen. |
duke@435 | 442 | MutableSpace* const old_space = old_gen->object_space(); |
jcoomes@916 | 443 | HeapWord* const unused_start = old_space->top(); |
jcoomes@916 | 444 | size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
duke@435 | 445 | |
jcoomes@916 | 446 | if (unused_words > 0) { |
jcoomes@916 | 447 | if (unused_words < CollectedHeap::min_fill_size()) { |
jcoomes@916 | 448 | return false; // If the old gen cannot be filled, must give up. |
jcoomes@916 | 449 | } |
jcoomes@916 | 450 | CollectedHeap::fill_with_objects(unused_start, unused_words); |
duke@435 | 451 | } |
duke@435 | 452 | |
duke@435 | 453 | // Take the live data from eden and set both top and end in the old gen to |
duke@435 | 454 | // eden top. (Need to set end because reset_after_change() mangles the region |
duke@435 | 455 | // from end to virtual_space->high() in debug builds). |
duke@435 | 456 | HeapWord* const new_top = eden_space->top(); |
duke@435 | 457 | old_gen->virtual_space()->expand_into(young_gen->virtual_space(), |
duke@435 | 458 | absorb_size); |
duke@435 | 459 | young_gen->reset_after_change(); |
duke@435 | 460 | old_space->set_top(new_top); |
duke@435 | 461 | old_space->set_end(new_top); |
duke@435 | 462 | old_gen->reset_after_change(); |
duke@435 | 463 | |
duke@435 | 464 | // Update the object start array for the filler object and the data from eden. |
duke@435 | 465 | ObjectStartArray* const start_array = old_gen->start_array(); |
jcoomes@916 | 466 | for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
jcoomes@916 | 467 | start_array->allocate_block(p); |
duke@435 | 468 | } |
duke@435 | 469 | |
duke@435 | 470 | // Could update the promoted average here, but it is not typically updated at |
duke@435 | 471 | // full GCs and the value to use is unclear. Something like |
duke@435 | 472 | // |
duke@435 | 473 | // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. |
duke@435 | 474 | |
duke@435 | 475 | size_policy->set_bytes_absorbed_from_eden(absorb_size); |
duke@435 | 476 | return true; |
duke@435 | 477 | } |
duke@435 | 478 | |
duke@435 | 479 | void PSMarkSweep::allocate_stacks() { |
duke@435 | 480 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 481 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 482 | |
duke@435 | 483 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 484 | |
duke@435 | 485 | MutableSpace* to_space = young_gen->to_space(); |
duke@435 | 486 | _preserved_marks = (PreservedMark*)to_space->top(); |
duke@435 | 487 | _preserved_count = 0; |
duke@435 | 488 | |
duke@435 | 489 | // We want to calculate the size in bytes first. |
duke@435 | 490 | _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); |
duke@435 | 491 | // Now divide by the size of a PreservedMark |
duke@435 | 492 | _preserved_count_max /= sizeof(PreservedMark); |
duke@435 | 493 | } |
duke@435 | 494 | |
duke@435 | 495 | |
duke@435 | 496 | void PSMarkSweep::deallocate_stacks() { |
jcoomes@2191 | 497 | _preserved_mark_stack.clear(true); |
jcoomes@2191 | 498 | _preserved_oop_stack.clear(true); |
jcoomes@2191 | 499 | _marking_stack.clear(); |
jcoomes@2191 | 500 | _objarray_stack.clear(true); |
jcoomes@2191 | 501 | _revisit_klass_stack.clear(true); |
jcoomes@2191 | 502 | _revisit_mdo_stack.clear(true); |
duke@435 | 503 | } |
duke@435 | 504 | |
duke@435 | 505 | void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { |
duke@435 | 506 | // Recursively traverse all live objects and mark them |
duke@435 | 507 | EventMark m("1 mark object"); |
duke@435 | 508 | TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 509 | trace(" 1"); |
duke@435 | 510 | |
duke@435 | 511 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 512 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 513 | |
duke@435 | 514 | // General strong roots. |
jrose@1424 | 515 | { |
jrose@1424 | 516 | ParallelScavengeHeap::ParStrongRootsScope psrs; |
jrose@1424 | 517 | Universe::oops_do(mark_and_push_closure()); |
jrose@1424 | 518 | JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles |
jrose@1424 | 519 | CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true); |
jrose@1424 | 520 | Threads::oops_do(mark_and_push_closure(), &each_active_code_blob); |
jrose@1424 | 521 | ObjectSynchronizer::oops_do(mark_and_push_closure()); |
jrose@1424 | 522 | FlatProfiler::oops_do(mark_and_push_closure()); |
jrose@1424 | 523 | Management::oops_do(mark_and_push_closure()); |
jrose@1424 | 524 | JvmtiExport::oops_do(mark_and_push_closure()); |
jrose@1424 | 525 | SystemDictionary::always_strong_oops_do(mark_and_push_closure()); |
jrose@1424 | 526 | // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. |
jrose@1424 | 527 | //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); |
jrose@1424 | 528 | } |
duke@435 | 529 | |
duke@435 | 530 | // Flush marking stack. |
duke@435 | 531 | follow_stack(); |
duke@435 | 532 | |
duke@435 | 533 | // Process reference objects found during marking |
duke@435 | 534 | { |
ysr@892 | 535 | ref_processor()->setup_policy(clear_all_softrefs); |
duke@435 | 536 | ref_processor()->process_discovered_references( |
ysr@888 | 537 | is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL); |
duke@435 | 538 | } |
duke@435 | 539 | |
duke@435 | 540 | // Follow system dictionary roots and unload classes |
duke@435 | 541 | bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); |
duke@435 | 542 | |
duke@435 | 543 | // Follow code cache roots |
duke@435 | 544 | CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), |
duke@435 | 545 | purged_class); |
duke@435 | 546 | follow_stack(); // Flush marking stack |
duke@435 | 547 | |
duke@435 | 548 | // Update subklass/sibling/implementor links of live klasses |
duke@435 | 549 | follow_weak_klass_links(); |
jcoomes@2191 | 550 | assert(_marking_stack.is_empty(), "just drained"); |
duke@435 | 551 | |
ysr@1376 | 552 | // Visit memoized mdo's and clear unmarked weak refs |
ysr@1376 | 553 | follow_mdo_weak_refs(); |
jcoomes@2191 | 554 | assert(_marking_stack.is_empty(), "just drained"); |
ysr@1376 | 555 | |
coleenp@2497 | 556 | // Visit interned string tables and delete unmarked oops |
duke@435 | 557 | StringTable::unlink(is_alive_closure()); |
coleenp@2497 | 558 | // Clean up unreferenced symbols in symbol table. |
coleenp@2497 | 559 | SymbolTable::unlink(); |
duke@435 | 560 | |
jcoomes@2191 | 561 | assert(_marking_stack.is_empty(), "stack should be empty by now"); |
duke@435 | 562 | } |
duke@435 | 563 | |
duke@435 | 564 | |
duke@435 | 565 | void PSMarkSweep::mark_sweep_phase2() { |
duke@435 | 566 | EventMark m("2 compute new addresses"); |
duke@435 | 567 | TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 568 | trace("2"); |
duke@435 | 569 | |
duke@435 | 570 | // Now all live objects are marked, compute the new object addresses. |
duke@435 | 571 | |
duke@435 | 572 | // It is imperative that we traverse perm_gen LAST. If dead space is |
duke@435 | 573 | // allowed a range of dead object may get overwritten by a dead int |
duke@435 | 574 | // array. If perm_gen is not traversed last a klassOop may get |
duke@435 | 575 | // overwritten. This is fine since it is dead, but if the class has dead |
duke@435 | 576 | // instances we have to skip them, and in order to find their size we |
duke@435 | 577 | // need the klassOop! |
duke@435 | 578 | // |
duke@435 | 579 | // It is not required that we traverse spaces in the same order in |
duke@435 | 580 | // phase2, phase3 and phase4, but the ValidateMarkSweep live oops |
duke@435 | 581 | // tracking expects us to do so. See comment under phase4. |
duke@435 | 582 | |
duke@435 | 583 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 584 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 585 | |
duke@435 | 586 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 587 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 588 | |
duke@435 | 589 | // Begin compacting into the old gen |
duke@435 | 590 | PSMarkSweepDecorator::set_destination_decorator_tenured(); |
duke@435 | 591 | |
duke@435 | 592 | // This will also compact the young gen spaces. |
duke@435 | 593 | old_gen->precompact(); |
duke@435 | 594 | |
duke@435 | 595 | // Compact the perm gen into the perm gen |
duke@435 | 596 | PSMarkSweepDecorator::set_destination_decorator_perm_gen(); |
duke@435 | 597 | |
duke@435 | 598 | perm_gen->precompact(); |
duke@435 | 599 | } |
duke@435 | 600 | |
duke@435 | 601 | // This should be moved to the shared markSweep code! |
duke@435 | 602 | class PSAlwaysTrueClosure: public BoolObjectClosure { |
duke@435 | 603 | public: |
duke@435 | 604 | void do_object(oop p) { ShouldNotReachHere(); } |
duke@435 | 605 | bool do_object_b(oop p) { return true; } |
duke@435 | 606 | }; |
duke@435 | 607 | static PSAlwaysTrueClosure always_true; |
duke@435 | 608 | |
duke@435 | 609 | void PSMarkSweep::mark_sweep_phase3() { |
duke@435 | 610 | // Adjust the pointers to reflect the new locations |
duke@435 | 611 | EventMark m("3 adjust pointers"); |
duke@435 | 612 | TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 613 | trace("3"); |
duke@435 | 614 | |
duke@435 | 615 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 616 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 617 | |
duke@435 | 618 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 619 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 620 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 621 | |
duke@435 | 622 | // General strong roots. |
duke@435 | 623 | Universe::oops_do(adjust_root_pointer_closure()); |
duke@435 | 624 | JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles |
jrose@1424 | 625 | Threads::oops_do(adjust_root_pointer_closure(), NULL); |
duke@435 | 626 | ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); |
duke@435 | 627 | FlatProfiler::oops_do(adjust_root_pointer_closure()); |
duke@435 | 628 | Management::oops_do(adjust_root_pointer_closure()); |
duke@435 | 629 | JvmtiExport::oops_do(adjust_root_pointer_closure()); |
duke@435 | 630 | // SO_AllClasses |
duke@435 | 631 | SystemDictionary::oops_do(adjust_root_pointer_closure()); |
jrose@1424 | 632 | //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure()); |
duke@435 | 633 | |
duke@435 | 634 | // Now adjust pointers in remaining weak roots. (All of which should |
duke@435 | 635 | // have been cleared if they pointed to non-surviving objects.) |
duke@435 | 636 | // Global (weak) JNI handles |
duke@435 | 637 | JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure()); |
duke@435 | 638 | |
duke@435 | 639 | CodeCache::oops_do(adjust_pointer_closure()); |
duke@435 | 640 | StringTable::oops_do(adjust_root_pointer_closure()); |
duke@435 | 641 | ref_processor()->weak_oops_do(adjust_root_pointer_closure()); |
duke@435 | 642 | PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); |
duke@435 | 643 | |
duke@435 | 644 | adjust_marks(); |
duke@435 | 645 | |
duke@435 | 646 | young_gen->adjust_pointers(); |
duke@435 | 647 | old_gen->adjust_pointers(); |
duke@435 | 648 | perm_gen->adjust_pointers(); |
duke@435 | 649 | } |
duke@435 | 650 | |
duke@435 | 651 | void PSMarkSweep::mark_sweep_phase4() { |
duke@435 | 652 | EventMark m("4 compact heap"); |
duke@435 | 653 | TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 654 | trace("4"); |
duke@435 | 655 | |
duke@435 | 656 | // All pointers are now adjusted, move objects accordingly |
duke@435 | 657 | |
duke@435 | 658 | // It is imperative that we traverse perm_gen first in phase4. All |
duke@435 | 659 | // classes must be allocated earlier than their instances, and traversing |
duke@435 | 660 | // perm_gen first makes sure that all klassOops have moved to their new |
duke@435 | 661 | // location before any instance does a dispatch through it's klass! |
duke@435 | 662 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 663 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 664 | |
duke@435 | 665 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 666 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 667 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 668 | |
duke@435 | 669 | perm_gen->compact(); |
duke@435 | 670 | old_gen->compact(); |
duke@435 | 671 | young_gen->compact(); |
duke@435 | 672 | } |
duke@435 | 673 | |
duke@435 | 674 | jlong PSMarkSweep::millis_since_last_gc() { |
johnc@3339 | 675 | // We need a monotonically non-deccreasing time in ms but |
johnc@3339 | 676 | // os::javaTimeMillis() does not guarantee monotonicity. |
johnc@3339 | 677 | jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
johnc@3339 | 678 | jlong ret_val = now - _time_of_last_gc; |
duke@435 | 679 | // XXX See note in genCollectedHeap::millis_since_last_gc(). |
duke@435 | 680 | if (ret_val < 0) { |
johnc@3339 | 681 | NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);) |
duke@435 | 682 | return 0; |
duke@435 | 683 | } |
duke@435 | 684 | return ret_val; |
duke@435 | 685 | } |
duke@435 | 686 | |
duke@435 | 687 | void PSMarkSweep::reset_millis_since_last_gc() { |
johnc@3339 | 688 | // We need a monotonically non-deccreasing time in ms but |
johnc@3339 | 689 | // os::javaTimeMillis() does not guarantee monotonicity. |
johnc@3339 | 690 | _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
duke@435 | 691 | } |