Exemplo n.º 1
0
// This method contains no policy. You should probably
// be calling invoke() instead.
void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
  assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
  assert(ref_processor() != NULL, "Sanity");

  if (GC_locker::check_active_before_gc()) {
    return;
  }

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
  GCCause::Cause gc_cause = heap->gc_cause();
  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
  PSAdaptiveSizePolicy* size_policy = heap->size_policy();

  PSYoungGen* young_gen = heap->young_gen();
  PSOldGen* old_gen = heap->old_gen();
  PSPermGen* perm_gen = heap->perm_gen();

  // Increment the invocation count
  heap->increment_total_collections(true /* full */);

  // Save information needed to minimize mangling
  heap->record_gen_tops_before_GC();

  // We need to track unique mark sweep invocations as well.
  _total_invocations++;

  AdaptiveSizePolicyOutput(size_policy, heap->total_collections());

  if (PrintHeapAtGC) {
    Universe::print_heap_before_gc();
  }

  // Fill in TLABs
  heap->accumulate_statistics_all_tlabs();
  heap->ensure_parsability(true);  // retire TLABs

  if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
    HandleMark hm;  // Discard invalid handles created during verification
    gclog_or_tty->print(" VerifyBeforeGC:");
    Universe::verify(true);
  }

  // Verify object start arrays
  if (VerifyObjectStartArray &&
      VerifyBeforeGC) {
    old_gen->verify_object_start_array();
    perm_gen->verify_object_start_array();
  }

  heap->pre_full_gc_dump();

  // Filled in below to track the state of the young gen after the collection.
  bool eden_empty;
  bool survivors_empty;
  bool young_gen_empty;

  {
    HandleMark hm;
    const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
    // This is useful for debugging but don't change the output the
    // the customer sees.
    const char* gc_cause_str = "Full GC";
    if (is_system_gc && PrintGCDetails) {
      gc_cause_str = "Full GC (System)";
    }
    gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
    TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
    TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty);
    TraceCollectorStats tcs(counters());
    TraceMemoryManagerStats tms(true /* Full GC */);

    if (TraceGen1Time) accumulated_time()->start();

    // Let the size policy know we're starting
    size_policy->major_collection_begin();

    // When collecting the permanent generation methodOops may be moving,
    // so we either have to flush all bcp data or convert it into bci.
    CodeCache::gc_prologue();
    Threads::gc_prologue();
    BiasedLocking::preserve_marks();

    // Capture heap size before collection for printing.
    size_t prev_used = heap->used();

    // Capture perm gen size before collection for sizing.
    size_t perm_gen_prev_used = perm_gen->used_in_bytes();

    // For PrintGCDetails
    size_t old_gen_prev_used = old_gen->used_in_bytes();
    size_t young_gen_prev_used = young_gen->used_in_bytes();

    allocate_stacks();

    NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
    COMPILER2_PRESENT(DerivedPointerTable::clear());

    ref_processor()->enable_discovery();
    ref_processor()->setup_policy(clear_all_softrefs);

    mark_sweep_phase1(clear_all_softrefs);

    mark_sweep_phase2();

    // Don't add any more derived pointers during phase3
    COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
    COMPILER2_PRESENT(DerivedPointerTable::set_active(false));

    mark_sweep_phase3();

    mark_sweep_phase4();

    restore_marks();

    deallocate_stacks();

    if (ZapUnusedHeapArea) {
      // Do a complete mangle (top to end) because the usage for
      // scratch does not maintain a top pointer.
      young_gen->to_space()->mangle_unused_area_complete();
    }

    eden_empty = young_gen->eden_space()->is_empty();
    if (!eden_empty) {
      eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
    }

    // Update heap occupancy information which is used as
    // input to soft ref clearing policy at the next gc.
    Universe::update_heap_info_at_gc();

    survivors_empty = young_gen->from_space()->is_empty() &&
                      young_gen->to_space()->is_empty();
    young_gen_empty = eden_empty && survivors_empty;

    BarrierSet* bs = heap->barrier_set();
    if (bs->is_a(BarrierSet::ModRef)) {
      ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
      MemRegion old_mr = heap->old_gen()->reserved();
      MemRegion perm_mr = heap->perm_gen()->reserved();
      assert(perm_mr.end() <= old_mr.start(), "Generations out of order");

      if (young_gen_empty) {
        modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
      } else {
        modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
      }
    }

    BiasedLocking::restore_marks();
    Threads::gc_epilogue();
    CodeCache::gc_epilogue();

    COMPILER2_PRESENT(DerivedPointerTable::update_pointers());

    ref_processor()->enqueue_discovered_references(NULL);

    // Update time of last GC
    reset_millis_since_last_gc();

    // Let the size policy know we're done
    size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);

    if (UseAdaptiveSizePolicy) {

      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print("AdaptiveSizeStart: ");
        gclog_or_tty->stamp();
        gclog_or_tty->print_cr(" collection: %d ",
                       heap->total_collections());
        if (Verbose) {
          gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
            " perm_gen_capacity: %d ",
            old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
            perm_gen->capacity_in_bytes());
        }
      }

      // Don't check if the size_policy is ready here.  Let
      // the size_policy check that internally.
      if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
          ((gc_cause != GCCause::_java_lang_system_gc) ||
            UseAdaptiveSizePolicyWithSystemGC)) {
        // Calculate optimal free space amounts
        assert(young_gen->max_size() >
          young_gen->from_space()->capacity_in_bytes() +
          young_gen->to_space()->capacity_in_bytes(),
          "Sizes of space in young gen are out-of-bounds");
        size_t max_eden_size = young_gen->max_size() -
          young_gen->from_space()->capacity_in_bytes() -
          young_gen->to_space()->capacity_in_bytes();
        size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
                                 young_gen->eden_space()->used_in_bytes(),
                                 old_gen->used_in_bytes(),
                                 perm_gen->used_in_bytes(),
                                 young_gen->eden_space()->capacity_in_bytes(),
                                 old_gen->max_gen_size(),
                                 max_eden_size,
                                 true /* full gc*/,
                                 gc_cause);

        heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());

        // Don't resize the young generation at an major collection.  A
        // desired young generation size may have been calculated but
        // resizing the young generation complicates the code because the
        // resizing of the old generation may have moved the boundary
        // between the young generation and the old generation.  Let the
        // young generation resizing happen at the minor collections.
      }
      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
                       heap->total_collections());
      }
    }

    if (UsePerfData) {
      heap->gc_policy_counters()->update_counters();
      heap->gc_policy_counters()->update_old_capacity(
        old_gen->capacity_in_bytes());
      heap->gc_policy_counters()->update_young_capacity(
        young_gen->capacity_in_bytes());
    }

    heap->resize_all_tlabs();

    // We collected the perm gen, so we'll resize it here.
    perm_gen->compute_new_size(perm_gen_prev_used);

    if (TraceGen1Time) accumulated_time()->stop();

    if (PrintGC) {
      if (PrintGCDetails) {
        // Don't print a GC timestamp here.  This is after the GC so
        // would be confusing.
        young_gen->print_used_change(young_gen_prev_used);
        old_gen->print_used_change(old_gen_prev_used);
      }
      heap->print_heap_change(prev_used);
      // Do perm gen after heap becase prev_used does
      // not include the perm gen (done this way in the other
      // collectors).
      if (PrintGCDetails) {
        perm_gen->print_used_change(perm_gen_prev_used);
      }
    }

    // Track memory usage and detect low memory
    MemoryService::track_memory_usage();
    heap->update_counters();

    if (PrintGCDetails) {
      if (size_policy->print_gc_time_limit_would_be_exceeded()) {
        if (size_policy->gc_time_limit_exceeded()) {
          gclog_or_tty->print_cr("      GC time is exceeding GCTimeLimit "
            "of %d%%", GCTimeLimit);
        } else {
          gclog_or_tty->print_cr("      GC time would exceed GCTimeLimit "
            "of %d%%", GCTimeLimit);
        }
      }
      size_policy->set_print_gc_time_limit_would_be_exceeded(false);
    }
  }

  if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
    HandleMark hm;  // Discard invalid handles created during verification
    gclog_or_tty->print(" VerifyAfterGC:");
    Universe::verify(false);
  }

  // Re-verify object start arrays
  if (VerifyObjectStartArray &&
      VerifyAfterGC) {
    old_gen->verify_object_start_array();
    perm_gen->verify_object_start_array();
  }

  if (ZapUnusedHeapArea) {
    old_gen->object_space()->check_mangled_unused_area_complete();
    perm_gen->object_space()->check_mangled_unused_area_complete();
  }

  NOT_PRODUCT(ref_processor()->verify_no_references_recorded());

  if (PrintHeapAtGC) {
    Universe::print_heap_after_gc();
  }

  heap->post_full_gc_dump();

#ifdef TRACESPINNING
  ParallelTaskTerminator::print_termination_counts();
#endif
}
Exemplo n.º 2
0
// This method contains no policy. You should probably
// be calling invoke() instead.
bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
  assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
  assert(ref_processor() != NULL, "Sanity");

  if (GC_locker::check_active_before_gc()) {
    return false;
  }

  ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  GCCause::Cause gc_cause = heap->gc_cause();

  _gc_timer->register_gc_start();
  _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start());

  PSAdaptiveSizePolicy* size_policy = heap->size_policy();

  // The scope of casr should end after code that can change
  // CollectorPolicy::_should_clear_all_soft_refs.
  ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy());

  PSYoungGen* young_gen = heap->young_gen();
  PSOldGen* old_gen = heap->old_gen();

  // Increment the invocation count
  heap->increment_total_collections(true /* full */);

  // Save information needed to minimize mangling
  heap->record_gen_tops_before_GC();

  // We need to track unique mark sweep invocations as well.
  _total_invocations++;

  AdaptiveSizePolicyOutput(size_policy, heap->total_collections());

  heap->print_heap_before_gc();
  heap->trace_heap_before_gc(_gc_tracer);

  // Fill in TLABs
  heap->accumulate_statistics_all_tlabs();
  heap->ensure_parsability(true);  // retire TLABs

  if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
    HandleMark hm;  // Discard invalid handles created during verification
    Universe::verify(" VerifyBeforeGC:");
  }

  // Verify object start arrays
  if (VerifyObjectStartArray &&
      VerifyBeforeGC) {
    old_gen->verify_object_start_array();
  }

  heap->pre_full_gc_dump(_gc_timer);

  // Filled in below to track the state of the young gen after the collection.
  bool eden_empty;
  bool survivors_empty;
  bool young_gen_empty;

  {
    HandleMark hm;

    TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
    GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer->gc_id());
    TraceCollectorStats tcs(counters());
    TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);

    if (TraceOldGenTime) accumulated_time()->start();

    // Let the size policy know we're starting
    size_policy->major_collection_begin();

    CodeCache::gc_prologue();
    BiasedLocking::preserve_marks();

    // Capture heap size before collection for printing.
    size_t prev_used = heap->used();

    // Capture metadata size before collection for sizing.
    size_t metadata_prev_used = MetaspaceAux::used_bytes();

    // For PrintGCDetails
    size_t old_gen_prev_used = old_gen->used_in_bytes();
    size_t young_gen_prev_used = young_gen->used_in_bytes();

    allocate_stacks();

    COMPILER2_PRESENT(DerivedPointerTable::clear());

    ref_processor()->enable_discovery();
    ref_processor()->setup_policy(clear_all_softrefs);

    mark_sweep_phase1(clear_all_softrefs);

    mark_sweep_phase2();

    // Don't add any more derived pointers during phase3
    COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
    COMPILER2_PRESENT(DerivedPointerTable::set_active(false));

    mark_sweep_phase3();

    mark_sweep_phase4();

    restore_marks();

    deallocate_stacks();

    if (ZapUnusedHeapArea) {
      // Do a complete mangle (top to end) because the usage for
      // scratch does not maintain a top pointer.
      young_gen->to_space()->mangle_unused_area_complete();
    }

    eden_empty = young_gen->eden_space()->is_empty();
    if (!eden_empty) {
      eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
    }

    // Update heap occupancy information which is used as
    // input to soft ref clearing policy at the next gc.
    Universe::update_heap_info_at_gc();

    survivors_empty = young_gen->from_space()->is_empty() &&
                      young_gen->to_space()->is_empty();
    young_gen_empty = eden_empty && survivors_empty;

    ModRefBarrierSet* modBS = barrier_set_cast<ModRefBarrierSet>(heap->barrier_set());
    MemRegion old_mr = heap->old_gen()->reserved();
    if (young_gen_empty) {
      modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
    } else {
      modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
    }

    // Delete metaspaces for unloaded class loaders and clean up loader_data graph
    ClassLoaderDataGraph::purge();
    MetaspaceAux::verify_metrics();

    BiasedLocking::restore_marks();
    CodeCache::gc_epilogue();
    JvmtiExport::gc_epilogue();

    COMPILER2_PRESENT(DerivedPointerTable::update_pointers());

    ref_processor()->enqueue_discovered_references(NULL);

    // Update time of last GC
    reset_millis_since_last_gc();

    // Let the size policy know we're done
    size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);

    if (UseAdaptiveSizePolicy) {

      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print("AdaptiveSizeStart: ");
        gclog_or_tty->stamp();
        gclog_or_tty->print_cr(" collection: %d ",
                       heap->total_collections());
        if (Verbose) {
          gclog_or_tty->print("old_gen_capacity: " SIZE_FORMAT
            " young_gen_capacity: " SIZE_FORMAT,
            old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
        }
      }

      // Don't check if the size_policy is ready here.  Let
      // the size_policy check that internally.
      if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
          ((gc_cause != GCCause::_java_lang_system_gc) ||
            UseAdaptiveSizePolicyWithSystemGC)) {
        // Swap the survivor spaces if from_space is empty. The
        // resize_young_gen() called below is normally used after
        // a successful young GC and swapping of survivor spaces;
        // otherwise, it will fail to resize the young gen with
        // the current implementation.
        if (young_gen->from_space()->is_empty()) {
          young_gen->from_space()->clear(SpaceDecorator::Mangle);
          young_gen->swap_spaces();
        }

        // Calculate optimal free space amounts
        assert(young_gen->max_size() >
          young_gen->from_space()->capacity_in_bytes() +
          young_gen->to_space()->capacity_in_bytes(),
          "Sizes of space in young gen are out-of-bounds");

        size_t young_live = young_gen->used_in_bytes();
        size_t eden_live = young_gen->eden_space()->used_in_bytes();
        size_t old_live = old_gen->used_in_bytes();
        size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
        size_t max_old_gen_size = old_gen->max_gen_size();
        size_t max_eden_size = young_gen->max_size() -
          young_gen->from_space()->capacity_in_bytes() -
          young_gen->to_space()->capacity_in_bytes();

        // Used for diagnostics
        size_policy->clear_generation_free_space_flags();

        size_policy->compute_generations_free_space(young_live,
                                                    eden_live,
                                                    old_live,
                                                    cur_eden,
                                                    max_old_gen_size,
                                                    max_eden_size,
                                                    true /* full gc*/);

        size_policy->check_gc_overhead_limit(young_live,
                                             eden_live,
                                             max_old_gen_size,
                                             max_eden_size,
                                             true /* full gc*/,
                                             gc_cause,
                                             heap->collector_policy());

        size_policy->decay_supplemental_growth(true /* full gc*/);

        heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());

        heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
                               size_policy->calculated_survivor_size_in_bytes());
      }
      if (PrintAdaptiveSizePolicy) {
        gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
                       heap->total_collections());
      }
    }

    if (UsePerfData) {
      heap->gc_policy_counters()->update_counters();
      heap->gc_policy_counters()->update_old_capacity(
        old_gen->capacity_in_bytes());
      heap->gc_policy_counters()->update_young_capacity(
        young_gen->capacity_in_bytes());
    }

    heap->resize_all_tlabs();

    // We collected the heap, recalculate the metaspace capacity
    MetaspaceGC::compute_new_size();

    if (TraceOldGenTime) accumulated_time()->stop();

    if (PrintGC) {
      if (PrintGCDetails) {
        // Don't print a GC timestamp here.  This is after the GC so
        // would be confusing.
        young_gen->print_used_change(young_gen_prev_used);
        old_gen->print_used_change(old_gen_prev_used);
      }
      heap->print_heap_change(prev_used);
      if (PrintGCDetails) {
        MetaspaceAux::print_metaspace_change(metadata_prev_used);
      }
    }

    // Track memory usage and detect low memory
    MemoryService::track_memory_usage();
    heap->update_counters();
  }

  if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
    HandleMark hm;  // Discard invalid handles created during verification
    Universe::verify(" VerifyAfterGC:");
  }

  // Re-verify object start arrays
  if (VerifyObjectStartArray &&
      VerifyAfterGC) {
    old_gen->verify_object_start_array();
  }

  if (ZapUnusedHeapArea) {
    old_gen->object_space()->check_mangled_unused_area_complete();
  }

  NOT_PRODUCT(ref_processor()->verify_no_references_recorded());

  heap->print_heap_after_gc();
  heap->trace_heap_after_gc(_gc_tracer);

  heap->post_full_gc_dump(_gc_timer);

#ifdef TRACESPINNING
  ParallelTaskTerminator::print_termination_counts();
#endif

  _gc_timer->register_gc_end();

  _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions());

  return true;
}