1 /*
   2  * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
   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  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc_implementation/parallelScavenge/adjoiningGenerations.hpp"
  27 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp"
  28 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
  29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
  30 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
  31 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
  32 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
  33 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
  34 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
  35 #include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
  36 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
  37 #include "gc_implementation/parallelScavenge/vmPSOperations.hpp"
  38 #include "gc_implementation/shared/gcHeapSummary.hpp"
  39 #include "gc_implementation/shared/gcWhen.hpp"
  40 #include "memory/gcLocker.inline.hpp"
  41 #include "oops/oop.inline.hpp"
  42 #include "runtime/handles.inline.hpp"
  43 #include "runtime/java.hpp"
  44 #include "runtime/vmThread.hpp"
  45 #include "services/memTracker.hpp"
  46 #include "utilities/vmError.hpp"
  47 
  48 PSYoungGen*  ParallelScavengeHeap::_young_gen = NULL;
  49 PSOldGen*    ParallelScavengeHeap::_old_gen = NULL;
  50 PSAdaptiveSizePolicy* ParallelScavengeHeap::_size_policy = NULL;
  51 PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
  52 ParallelScavengeHeap* ParallelScavengeHeap::_psh = NULL;
  53 GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
  54 
  55 static void trace_gen_sizes(const char* const str,
  56                             size_t og_min, size_t og_max,
  57                             size_t yg_min, size_t yg_max)
  58 {
  59   if (TracePageSizes) {
  60     tty->print_cr("%s:  " SIZE_FORMAT "," SIZE_FORMAT " "
  61                   SIZE_FORMAT "," SIZE_FORMAT " "
  62                   SIZE_FORMAT,
  63                   str,
  64                   og_min / K, og_max / K,
  65                   yg_min / K, yg_max / K,
  66                   (og_max + yg_max) / K);
  67   }
  68 }
  69 
  70 jint ParallelScavengeHeap::initialize() {
  71   CollectedHeap::pre_initialize();
  72 
  73   // Cannot be initialized until after the flags are parsed
  74   // GenerationSizer flag_parser;
  75   _collector_policy = new GenerationSizer();
  76 
  77   size_t yg_min_size = _collector_policy->min_young_gen_size();
  78   size_t yg_max_size = _collector_policy->max_young_gen_size();
  79   size_t og_min_size = _collector_policy->min_old_gen_size();
  80   size_t og_max_size = _collector_policy->max_old_gen_size();
  81 
  82   trace_gen_sizes("ps heap raw",
  83                   og_min_size, og_max_size,
  84                   yg_min_size, yg_max_size);
  85 
  86   const size_t og_page_sz = os::page_size_for_region(yg_min_size + og_min_size,
  87                                                      yg_max_size + og_max_size,
  88                                                      8);
  89 
  90   const size_t og_align = set_alignment(_old_gen_alignment,   og_page_sz);
  91   const size_t yg_align = set_alignment(_young_gen_alignment, og_page_sz);
  92 
  93   // Update sizes to reflect the selected page size(s).
  94   //
  95   // NEEDS_CLEANUP.  The default TwoGenerationCollectorPolicy uses NewRatio; it
  96   // should check UseAdaptiveSizePolicy.  Changes from generationSizer could
  97   // move to the common code.
  98   yg_min_size = align_size_up(yg_min_size, yg_align);
  99   yg_max_size = align_size_up(yg_max_size, yg_align);
 100   size_t yg_cur_size =
 101     align_size_up(_collector_policy->young_gen_size(), yg_align);
 102   yg_cur_size = MAX2(yg_cur_size, yg_min_size);
 103 
 104   og_min_size = align_size_up(og_min_size, og_align);
 105   // Align old gen size down to preserve specified heap size.
 106   assert(og_align == yg_align, "sanity");
 107   og_max_size = align_size_down(og_max_size, og_align);
 108   og_max_size = MAX2(og_max_size, og_min_size);
 109   size_t og_cur_size =
 110     align_size_down(_collector_policy->old_gen_size(), og_align);
 111   og_cur_size = MAX2(og_cur_size, og_min_size);
 112 
 113   trace_gen_sizes("ps heap rnd",
 114                   og_min_size, og_max_size,
 115                   yg_min_size, yg_max_size);
 116 
 117   const size_t heap_size = og_max_size + yg_max_size;
 118 
 119   ReservedSpace heap_rs = Universe::reserve_heap(heap_size, og_align);
 120 
 121   MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtJavaHeap);
 122 
 123   os::trace_page_sizes("ps main", og_min_size + yg_min_size,
 124                        og_max_size + yg_max_size, og_page_sz,
 125                        heap_rs.base(),
 126                        heap_rs.size());
 127   if (!heap_rs.is_reserved()) {
 128     vm_shutdown_during_initialization(
 129       "Could not reserve enough space for object heap");
 130     return JNI_ENOMEM;
 131   }
 132 
 133   _reserved = MemRegion((HeapWord*)heap_rs.base(),
 134                         (HeapWord*)(heap_rs.base() + heap_rs.size()));
 135 
 136   CardTableExtension* const barrier_set = new CardTableExtension(_reserved, 3);
 137   _barrier_set = barrier_set;
 138   oopDesc::set_bs(_barrier_set);
 139   if (_barrier_set == NULL) {
 140     vm_shutdown_during_initialization(
 141       "Could not reserve enough space for barrier set");
 142     return JNI_ENOMEM;
 143   }
 144 
 145   // Initial young gen size is 4 Mb
 146   //
 147   // XXX - what about flag_parser.young_gen_size()?
 148   const size_t init_young_size = align_size_up(4 * M, yg_align);
 149   yg_cur_size = MAX2(MIN2(init_young_size, yg_max_size), yg_cur_size);
 150 
 151   // Make up the generations
 152   // Calculate the maximum size that a generation can grow.  This
 153   // includes growth into the other generation.  Note that the
 154   // parameter _max_gen_size is kept as the maximum
 155   // size of the generation as the boundaries currently stand.
 156   // _max_gen_size is still used as that value.
 157   double max_gc_pause_sec = ((double) MaxGCPauseMillis)/1000.0;
 158   double max_gc_minor_pause_sec = ((double) MaxGCMinorPauseMillis)/1000.0;
 159 
 160   _gens = new AdjoiningGenerations(heap_rs,
 161                                    og_cur_size,
 162                                    og_min_size,
 163                                    og_max_size,
 164                                    yg_cur_size,
 165                                    yg_min_size,
 166                                    yg_max_size,
 167                                    yg_align);
 168 
 169   _old_gen = _gens->old_gen();
 170   _young_gen = _gens->young_gen();
 171 
 172   const size_t eden_capacity = _young_gen->eden_space()->capacity_in_bytes();
 173   const size_t old_capacity = _old_gen->capacity_in_bytes();
 174   const size_t initial_promo_size = MIN2(eden_capacity, old_capacity);
 175   _size_policy =
 176     new PSAdaptiveSizePolicy(eden_capacity,
 177                              initial_promo_size,
 178                              young_gen()->to_space()->capacity_in_bytes(),
 179                              intra_heap_alignment(),
 180                              max_gc_pause_sec,
 181                              max_gc_minor_pause_sec,
 182                              GCTimeRatio
 183                              );
 184 
 185   assert(!UseAdaptiveGCBoundary ||
 186     (old_gen()->virtual_space()->high_boundary() ==
 187      young_gen()->virtual_space()->low_boundary()),
 188     "Boundaries must meet");
 189   // initialize the policy counters - 2 collectors, 3 generations
 190   _gc_policy_counters =
 191     new PSGCAdaptivePolicyCounters("ParScav:MSC", 2, 3, _size_policy);
 192   _psh = this;
 193 
 194   // Set up the GCTaskManager
 195   _gc_task_manager = GCTaskManager::create(ParallelGCThreads);
 196 
 197   if (UseParallelOldGC && !PSParallelCompact::initialize()) {
 198     return JNI_ENOMEM;
 199   }
 200 
 201   return JNI_OK;
 202 }
 203 
 204 void ParallelScavengeHeap::post_initialize() {
 205   // Need to init the tenuring threshold
 206   PSScavenge::initialize();
 207   if (UseParallelOldGC) {
 208     PSParallelCompact::post_initialize();
 209   } else {
 210     PSMarkSweep::initialize();
 211   }
 212   PSPromotionManager::initialize();
 213 }
 214 
 215 void ParallelScavengeHeap::update_counters() {
 216   young_gen()->update_counters();
 217   old_gen()->update_counters();
 218   MetaspaceCounters::update_performance_counters();
 219 }
 220 
 221 size_t ParallelScavengeHeap::capacity() const {
 222   size_t value = young_gen()->capacity_in_bytes() + old_gen()->capacity_in_bytes();
 223   return value;
 224 }
 225 
 226 size_t ParallelScavengeHeap::used() const {
 227   size_t value = young_gen()->used_in_bytes() + old_gen()->used_in_bytes();
 228   return value;
 229 }
 230 
 231 bool ParallelScavengeHeap::is_maximal_no_gc() const {
 232   return old_gen()->is_maximal_no_gc() && young_gen()->is_maximal_no_gc();
 233 }
 234 
 235 
 236 size_t ParallelScavengeHeap::max_capacity() const {
 237   size_t estimated = reserved_region().byte_size();
 238   if (UseAdaptiveSizePolicy) {
 239     estimated -= _size_policy->max_survivor_size(young_gen()->max_size());
 240   } else {
 241     estimated -= young_gen()->to_space()->capacity_in_bytes();
 242   }
 243   return MAX2(estimated, capacity());
 244 }
 245 
 246 bool ParallelScavengeHeap::is_in(const void* p) const {
 247   if (young_gen()->is_in(p)) {
 248     return true;
 249   }
 250 
 251   if (old_gen()->is_in(p)) {
 252     return true;
 253   }
 254 
 255   return false;
 256 }
 257 
 258 bool ParallelScavengeHeap::is_in_reserved(const void* p) const {
 259   if (young_gen()->is_in_reserved(p)) {
 260     return true;
 261   }
 262 
 263   if (old_gen()->is_in_reserved(p)) {
 264     return true;
 265   }
 266 
 267   return false;
 268 }
 269 
 270 bool ParallelScavengeHeap::is_scavengable(const void* addr) {
 271   return is_in_young((oop)addr);
 272 }
 273 
 274 #ifdef ASSERT
 275 // Don't implement this by using is_in_young().  This method is used
 276 // in some cases to check that is_in_young() is correct.
 277 bool ParallelScavengeHeap::is_in_partial_collection(const void *p) {
 278   assert(is_in_reserved(p) || p == NULL,
 279     "Does not work if address is non-null and outside of the heap");
 280   // The order of the generations is old (low addr), young (high addr)
 281   return p >= old_gen()->reserved().end();
 282 }
 283 #endif
 284 
 285 // There are two levels of allocation policy here.
 286 //
 287 // When an allocation request fails, the requesting thread must invoke a VM
 288 // operation, transfer control to the VM thread, and await the results of a
 289 // garbage collection. That is quite expensive, and we should avoid doing it
 290 // multiple times if possible.
 291 //
 292 // To accomplish this, we have a basic allocation policy, and also a
 293 // failed allocation policy.
 294 //
 295 // The basic allocation policy controls how you allocate memory without
 296 // attempting garbage collection. It is okay to grab locks and
 297 // expand the heap, if that can be done without coming to a safepoint.
 298 // It is likely that the basic allocation policy will not be very
 299 // aggressive.
 300 //
 301 // The failed allocation policy is invoked from the VM thread after
 302 // the basic allocation policy is unable to satisfy a mem_allocate
 303 // request. This policy needs to cover the entire range of collection,
 304 // heap expansion, and out-of-memory conditions. It should make every
 305 // attempt to allocate the requested memory.
 306 
 307 // Basic allocation policy. Should never be called at a safepoint, or
 308 // from the VM thread.
 309 //
 310 // This method must handle cases where many mem_allocate requests fail
 311 // simultaneously. When that happens, only one VM operation will succeed,
 312 // and the rest will not be executed. For that reason, this method loops
 313 // during failed allocation attempts. If the java heap becomes exhausted,
 314 // we rely on the size_policy object to force a bail out.
 315 HeapWord* ParallelScavengeHeap::mem_allocate(
 316                                      size_t size,
 317                                      bool* gc_overhead_limit_was_exceeded) {
 318   assert(!SafepointSynchronize::is_at_safepoint(), "should not be at safepoint");
 319   assert(Thread::current() != (Thread*)VMThread::vm_thread(), "should not be in vm thread");
 320   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
 321 
 322   // In general gc_overhead_limit_was_exceeded should be false so
 323   // set it so here and reset it to true only if the gc time
 324   // limit is being exceeded as checked below.
 325   *gc_overhead_limit_was_exceeded = false;
 326 
 327   HeapWord* result = young_gen()->allocate(size);
 328 
 329   uint loop_count = 0;
 330   uint gc_count = 0;
 331   int gclocker_stalled_count = 0;
 332 
 333   while (result == NULL) {
 334     // We don't want to have multiple collections for a single filled generation.
 335     // To prevent this, each thread tracks the total_collections() value, and if
 336     // the count has changed, does not do a new collection.
 337     //
 338     // The collection count must be read only while holding the heap lock. VM
 339     // operations also hold the heap lock during collections. There is a lock
 340     // contention case where thread A blocks waiting on the Heap_lock, while
 341     // thread B is holding it doing a collection. When thread A gets the lock,
 342     // the collection count has already changed. To prevent duplicate collections,
 343     // The policy MUST attempt allocations during the same period it reads the
 344     // total_collections() value!
 345     {
 346       MutexLocker ml(Heap_lock);
 347       gc_count = Universe::heap()->total_collections();
 348 
 349       result = young_gen()->allocate(size);
 350       if (result != NULL) {
 351         return result;
 352       }
 353 
 354       // If certain conditions hold, try allocating from the old gen.
 355       result = mem_allocate_old_gen(size);
 356       if (result != NULL) {
 357         return result;
 358       }
 359 
 360       if (gclocker_stalled_count > GCLockerRetryAllocationCount) {
 361         return NULL;
 362       }
 363 
 364       // Failed to allocate without a gc.
 365       if (GC_locker::is_active_and_needs_gc()) {
 366         // If this thread is not in a jni critical section, we stall
 367         // the requestor until the critical section has cleared and
 368         // GC allowed. When the critical section clears, a GC is
 369         // initiated by the last thread exiting the critical section; so
 370         // we retry the allocation sequence from the beginning of the loop,
 371         // rather than causing more, now probably unnecessary, GC attempts.
 372         JavaThread* jthr = JavaThread::current();
 373         if (!jthr->in_critical()) {
 374           MutexUnlocker mul(Heap_lock);
 375           GC_locker::stall_until_clear();
 376           gclocker_stalled_count += 1;
 377           continue;
 378         } else {
 379           if (CheckJNICalls) {
 380             fatal("Possible deadlock due to allocating while"
 381                   " in jni critical section");
 382           }
 383           return NULL;
 384         }
 385       }
 386     }
 387 
 388     if (result == NULL) {
 389       // Generate a VM operation
 390       VM_ParallelGCFailedAllocation op(size, gc_count);
 391       VMThread::execute(&op);
 392 
 393       // Did the VM operation execute? If so, return the result directly.
 394       // This prevents us from looping until time out on requests that can
 395       // not be satisfied.
 396       if (op.prologue_succeeded()) {
 397         assert(Universe::heap()->is_in_or_null(op.result()),
 398           "result not in heap");
 399 
 400         // If GC was locked out during VM operation then retry allocation
 401         // and/or stall as necessary.
 402         if (op.gc_locked()) {
 403           assert(op.result() == NULL, "must be NULL if gc_locked() is true");
 404           continue;  // retry and/or stall as necessary
 405         }
 406 
 407         // Exit the loop if the gc time limit has been exceeded.
 408         // The allocation must have failed above ("result" guarding
 409         // this path is NULL) and the most recent collection has exceeded the
 410         // gc overhead limit (although enough may have been collected to
 411         // satisfy the allocation).  Exit the loop so that an out-of-memory
 412         // will be thrown (return a NULL ignoring the contents of
 413         // op.result()),
 414         // but clear gc_overhead_limit_exceeded so that the next collection
 415         // starts with a clean slate (i.e., forgets about previous overhead
 416         // excesses).  Fill op.result() with a filler object so that the
 417         // heap remains parsable.
 418         const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded();
 419         const bool softrefs_clear = collector_policy()->all_soft_refs_clear();
 420 
 421         if (limit_exceeded && softrefs_clear) {
 422           *gc_overhead_limit_was_exceeded = true;
 423           size_policy()->set_gc_overhead_limit_exceeded(false);
 424           if (PrintGCDetails && Verbose) {
 425             gclog_or_tty->print_cr("ParallelScavengeHeap::mem_allocate: "
 426               "return NULL because gc_overhead_limit_exceeded is set");
 427           }
 428           if (op.result() != NULL) {
 429             CollectedHeap::fill_with_object(op.result(), size);
 430           }
 431           return NULL;
 432         }
 433 
 434         return op.result();
 435       }
 436     }
 437 
 438     // The policy object will prevent us from looping forever. If the
 439     // time spent in gc crosses a threshold, we will bail out.
 440     loop_count++;
 441     if ((result == NULL) && (QueuedAllocationWarningCount > 0) &&
 442         (loop_count % QueuedAllocationWarningCount == 0)) {
 443       warning("ParallelScavengeHeap::mem_allocate retries %d times \n\t"
 444               " size=%d", loop_count, size);
 445     }
 446   }
 447 
 448   return result;
 449 }
 450 
 451 // A "death march" is a series of ultra-slow allocations in which a full gc is
 452 // done before each allocation, and after the full gc the allocation still
 453 // cannot be satisfied from the young gen.  This routine detects that condition;
 454 // it should be called after a full gc has been done and the allocation
 455 // attempted from the young gen. The parameter 'addr' should be the result of
 456 // that young gen allocation attempt.
 457 void
 458 ParallelScavengeHeap::death_march_check(HeapWord* const addr, size_t size) {
 459   if (addr != NULL) {
 460     _death_march_count = 0;  // death march has ended
 461   } else if (_death_march_count == 0) {
 462     if (should_alloc_in_eden(size)) {
 463       _death_march_count = 1;    // death march has started
 464     }
 465   }
 466 }
 467 
 468 HeapWord* ParallelScavengeHeap::mem_allocate_old_gen(size_t size) {
 469   if (!should_alloc_in_eden(size) || GC_locker::is_active_and_needs_gc()) {
 470     // Size is too big for eden, or gc is locked out.
 471     return old_gen()->allocate(size);
 472   }
 473 
 474   // If a "death march" is in progress, allocate from the old gen a limited
 475   // number of times before doing a GC.
 476   if (_death_march_count > 0) {
 477     if (_death_march_count < 64) {
 478       ++_death_march_count;
 479       return old_gen()->allocate(size);
 480     } else {
 481       _death_march_count = 0;
 482     }
 483   }
 484   return NULL;
 485 }
 486 
 487 void ParallelScavengeHeap::do_full_collection(bool clear_all_soft_refs) {
 488   if (UseParallelOldGC) {
 489     // The do_full_collection() parameter clear_all_soft_refs
 490     // is interpreted here as maximum_compaction which will
 491     // cause SoftRefs to be cleared.
 492     bool maximum_compaction = clear_all_soft_refs;
 493     PSParallelCompact::invoke(maximum_compaction);
 494   } else {
 495     PSMarkSweep::invoke(clear_all_soft_refs);
 496   }
 497 }
 498 
 499 // Failed allocation policy. Must be called from the VM thread, and
 500 // only at a safepoint! Note that this method has policy for allocation
 501 // flow, and NOT collection policy. So we do not check for gc collection
 502 // time over limit here, that is the responsibility of the heap specific
 503 // collection methods. This method decides where to attempt allocations,
 504 // and when to attempt collections, but no collection specific policy.
 505 HeapWord* ParallelScavengeHeap::failed_mem_allocate(size_t size) {
 506   assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
 507   assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
 508   assert(!Universe::heap()->is_gc_active(), "not reentrant");
 509   assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
 510 
 511   // We assume that allocation in eden will fail unless we collect.
 512 
 513   // First level allocation failure, scavenge and allocate in young gen.
 514   GCCauseSetter gccs(this, GCCause::_allocation_failure);
 515   const bool invoked_full_gc = PSScavenge::invoke();
 516   HeapWord* result = young_gen()->allocate(size);
 517 
 518   // Second level allocation failure.
 519   //   Mark sweep and allocate in young generation.
 520   if (result == NULL && !invoked_full_gc) {
 521     do_full_collection(false);
 522     result = young_gen()->allocate(size);
 523   }
 524 
 525   death_march_check(result, size);
 526 
 527   // Third level allocation failure.
 528   //   After mark sweep and young generation allocation failure,
 529   //   allocate in old generation.
 530   if (result == NULL) {
 531     result = old_gen()->allocate(size);
 532   }
 533 
 534   // Fourth level allocation failure. We're running out of memory.
 535   //   More complete mark sweep and allocate in young generation.
 536   if (result == NULL) {
 537     do_full_collection(true);
 538     result = young_gen()->allocate(size);
 539   }
 540 
 541   // Fifth level allocation failure.
 542   //   After more complete mark sweep, allocate in old generation.
 543   if (result == NULL) {
 544     result = old_gen()->allocate(size);
 545   }
 546 
 547   return result;
 548 }
 549 
 550 void ParallelScavengeHeap::ensure_parsability(bool retire_tlabs) {
 551   CollectedHeap::ensure_parsability(retire_tlabs);
 552   young_gen()->eden_space()->ensure_parsability();
 553 }
 554 
 555 size_t ParallelScavengeHeap::unsafe_max_alloc() {
 556   return young_gen()->eden_space()->free_in_bytes();
 557 }
 558 
 559 size_t ParallelScavengeHeap::tlab_capacity(Thread* thr) const {
 560   return young_gen()->eden_space()->tlab_capacity(thr);
 561 }
 562 
 563 size_t ParallelScavengeHeap::unsafe_max_tlab_alloc(Thread* thr) const {
 564   return young_gen()->eden_space()->unsafe_max_tlab_alloc(thr);
 565 }
 566 
 567 HeapWord* ParallelScavengeHeap::allocate_new_tlab(size_t size) {
 568   return young_gen()->allocate(size);
 569 }
 570 
 571 void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
 572   CollectedHeap::accumulate_statistics_all_tlabs();
 573 }
 574 
 575 void ParallelScavengeHeap::resize_all_tlabs() {
 576   CollectedHeap::resize_all_tlabs();
 577 }
 578 
 579 bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) {
 580   // We don't need barriers for stores to objects in the
 581   // young gen and, a fortiori, for initializing stores to
 582   // objects therein.
 583   return is_in_young(new_obj);
 584 }
 585 
 586 // This method is used by System.gc() and JVMTI.
 587 void ParallelScavengeHeap::collect(GCCause::Cause cause) {
 588   assert(!Heap_lock->owned_by_self(),
 589     "this thread should not own the Heap_lock");
 590 
 591   unsigned int gc_count      = 0;
 592   unsigned int full_gc_count = 0;
 593   {
 594     MutexLocker ml(Heap_lock);
 595     // This value is guarded by the Heap_lock
 596     gc_count      = Universe::heap()->total_collections();
 597     full_gc_count = Universe::heap()->total_full_collections();
 598   }
 599 
 600   VM_ParallelGCSystemGC op(gc_count, full_gc_count, cause);
 601   VMThread::execute(&op);
 602 }
 603 
 604 void ParallelScavengeHeap::oop_iterate(ExtendedOopClosure* cl) {
 605   Unimplemented();
 606 }
 607 
 608 void ParallelScavengeHeap::object_iterate(ObjectClosure* cl) {
 609   young_gen()->object_iterate(cl);
 610   old_gen()->object_iterate(cl);
 611 }
 612 
 613 
 614 HeapWord* ParallelScavengeHeap::block_start(const void* addr) const {
 615   if (young_gen()->is_in_reserved(addr)) {
 616     assert(young_gen()->is_in(addr),
 617            "addr should be in allocated part of young gen");
 618     // called from os::print_location by find or VMError
 619     if (Debugging || VMError::fatal_error_in_progress())  return NULL;
 620     Unimplemented();
 621   } else if (old_gen()->is_in_reserved(addr)) {
 622     assert(old_gen()->is_in(addr),
 623            "addr should be in allocated part of old gen");
 624     return old_gen()->start_array()->object_start((HeapWord*)addr);
 625   }
 626   return 0;
 627 }
 628 
 629 size_t ParallelScavengeHeap::block_size(const HeapWord* addr) const {
 630   return oop(addr)->size();
 631 }
 632 
 633 bool ParallelScavengeHeap::block_is_obj(const HeapWord* addr) const {
 634   return block_start(addr) == addr;
 635 }
 636 
 637 jlong ParallelScavengeHeap::millis_since_last_gc() {
 638   return UseParallelOldGC ?
 639     PSParallelCompact::millis_since_last_gc() :
 640     PSMarkSweep::millis_since_last_gc();
 641 }
 642 
 643 void ParallelScavengeHeap::prepare_for_verify() {
 644   ensure_parsability(false);  // no need to retire TLABs for verification
 645 }
 646 
 647 PSHeapSummary ParallelScavengeHeap::create_ps_heap_summary() {
 648   PSOldGen* old = old_gen();
 649   HeapWord* old_committed_end = (HeapWord*)old->virtual_space()->committed_high_addr();
 650   VirtualSpaceSummary old_summary(old->reserved().start(), old_committed_end, old->reserved().end());
 651   SpaceSummary old_space(old->reserved().start(), old_committed_end, old->used_in_bytes());
 652 
 653   PSYoungGen* young = young_gen();
 654   VirtualSpaceSummary young_summary(young->reserved().start(),
 655     (HeapWord*)young->virtual_space()->committed_high_addr(), young->reserved().end());
 656 
 657   MutableSpace* eden = young_gen()->eden_space();
 658   SpaceSummary eden_space(eden->bottom(), eden->end(), eden->used_in_bytes());
 659 
 660   MutableSpace* from = young_gen()->from_space();
 661   SpaceSummary from_space(from->bottom(), from->end(), from->used_in_bytes());
 662 
 663   MutableSpace* to = young_gen()->to_space();
 664   SpaceSummary to_space(to->bottom(), to->end(), to->used_in_bytes());
 665 
 666   VirtualSpaceSummary heap_summary = create_heap_space_summary();
 667   return PSHeapSummary(heap_summary, used(), old_summary, old_space, young_summary, eden_space, from_space, to_space);
 668 }
 669 
 670 void ParallelScavengeHeap::print_on(outputStream* st) const {
 671   young_gen()->print_on(st);
 672   old_gen()->print_on(st);
 673   MetaspaceAux::print_on(st);
 674 }
 675 
 676 void ParallelScavengeHeap::print_on_error(outputStream* st) const {
 677   this->CollectedHeap::print_on_error(st);
 678 
 679   if (UseParallelOldGC) {
 680     st->cr();
 681     PSParallelCompact::print_on_error(st);
 682   }
 683 }
 684 
 685 void ParallelScavengeHeap::gc_threads_do(ThreadClosure* tc) const {
 686   PSScavenge::gc_task_manager()->threads_do(tc);
 687 }
 688 
 689 void ParallelScavengeHeap::print_gc_threads_on(outputStream* st) const {
 690   PSScavenge::gc_task_manager()->print_threads_on(st);
 691 }
 692 
 693 void ParallelScavengeHeap::print_tracing_info() const {
 694   if (TraceGen0Time) {
 695     double time = PSScavenge::accumulated_time()->seconds();
 696     tty->print_cr("[Accumulated GC generation 0 time %3.7f secs]", time);
 697   }
 698   if (TraceGen1Time) {
 699     double time = UseParallelOldGC ? PSParallelCompact::accumulated_time()->seconds() : PSMarkSweep::accumulated_time()->seconds();
 700     tty->print_cr("[Accumulated GC generation 1 time %3.7f secs]", time);
 701   }
 702 }
 703 
 704 
 705 void ParallelScavengeHeap::verify(bool silent, VerifyOption option /* ignored */) {
 706   // Why do we need the total_collections()-filter below?
 707   if (total_collections() > 0) {
 708     if (!silent) {
 709       gclog_or_tty->print("tenured ");
 710     }
 711     old_gen()->verify();
 712 
 713     if (!silent) {
 714       gclog_or_tty->print("eden ");
 715     }
 716     young_gen()->verify();
 717   }
 718 }
 719 
 720 void ParallelScavengeHeap::print_heap_change(size_t prev_used) {
 721   if (PrintGCDetails && Verbose) {
 722     gclog_or_tty->print(" "  SIZE_FORMAT
 723                         "->" SIZE_FORMAT
 724                         "("  SIZE_FORMAT ")",
 725                         prev_used, used(), capacity());
 726   } else {
 727     gclog_or_tty->print(" "  SIZE_FORMAT "K"
 728                         "->" SIZE_FORMAT "K"
 729                         "("  SIZE_FORMAT "K)",
 730                         prev_used / K, used() / K, capacity() / K);
 731   }
 732 }
 733 
 734 void ParallelScavengeHeap::trace_heap(GCWhen::Type when, GCTracer* gc_tracer) {
 735   const PSHeapSummary& heap_summary = create_ps_heap_summary();
 736   const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
 737   gc_tracer->report_gc_heap_summary(when, heap_summary, metaspace_summary);
 738 }
 739 
 740 ParallelScavengeHeap* ParallelScavengeHeap::heap() {
 741   assert(_psh != NULL, "Uninitialized access to ParallelScavengeHeap::heap()");
 742   assert(_psh->kind() == CollectedHeap::ParallelScavengeHeap, "not a parallel scavenge heap");
 743   return _psh;
 744 }
 745 
 746 // Before delegating the resize to the young generation,
 747 // the reserved space for the young and old generations
 748 // may be changed to accomodate the desired resize.
 749 void ParallelScavengeHeap::resize_young_gen(size_t eden_size,
 750     size_t survivor_size) {
 751   if (UseAdaptiveGCBoundary) {
 752     if (size_policy()->bytes_absorbed_from_eden() != 0) {
 753       size_policy()->reset_bytes_absorbed_from_eden();
 754       return;  // The generation changed size already.
 755     }
 756     gens()->adjust_boundary_for_young_gen_needs(eden_size, survivor_size);
 757   }
 758 
 759   // Delegate the resize to the generation.
 760   _young_gen->resize(eden_size, survivor_size);
 761 }
 762 
 763 // Before delegating the resize to the old generation,
 764 // the reserved space for the young and old generations
 765 // may be changed to accomodate the desired resize.
 766 void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
 767   if (UseAdaptiveGCBoundary) {
 768     if (size_policy()->bytes_absorbed_from_eden() != 0) {
 769       size_policy()->reset_bytes_absorbed_from_eden();
 770       return;  // The generation changed size already.
 771     }
 772     gens()->adjust_boundary_for_old_gen_needs(desired_free_space);
 773   }
 774 
 775   // Delegate the resize to the generation.
 776   _old_gen->resize(desired_free_space);
 777 }
 778 
 779 ParallelScavengeHeap::ParStrongRootsScope::ParStrongRootsScope() {
 780   // nothing particular
 781 }
 782 
 783 ParallelScavengeHeap::ParStrongRootsScope::~ParStrongRootsScope() {
 784   // nothing particular
 785 }
 786 
 787 #ifndef PRODUCT
 788 void ParallelScavengeHeap::record_gen_tops_before_GC() {
 789   if (ZapUnusedHeapArea) {
 790     young_gen()->record_spaces_top();
 791     old_gen()->record_spaces_top();
 792   }
 793 }
 794 
 795 void ParallelScavengeHeap::gen_mangle_unused_area() {
 796   if (ZapUnusedHeapArea) {
 797     young_gen()->eden_space()->mangle_unused_area();
 798     young_gen()->to_space()->mangle_unused_area();
 799     young_gen()->from_space()->mangle_unused_area();
 800     old_gen()->object_space()->mangle_unused_area();
 801   }
 802 }
 803 #endif