share/memory/metaspace.cpp

/*
 * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"

#include "aot/aotLoader.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/filemap.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/metachunk.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
#include "memory/metaspace/printCLDMetaspaceInfoClosure.hpp"
#include "memory/metaspace/spaceManager.hpp"
#include "memory/metaspace/virtualSpaceList.hpp"
#include "memory/metaspaceShared.hpp"
#include "memory/metaspaceTracer.hpp"
#include "memory/universe.hpp"
#include "runtime/init.hpp"
#include "runtime/orderAccess.hpp"
#include "services/memTracker.hpp"
#include "utilities/copy.hpp"
#include "utilities/debug.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/globalDefinitions.hpp"


using namespace metaspace;

MetaWord* last_allocated = 0;

size_t Metaspace::_compressed_class_space_size;
const MetaspaceTracer* Metaspace::_tracer = NULL;

DEBUG_ONLY(bool Metaspace::_frozen = false;)

static const char* space_type_name(Metaspace::MetaspaceType t) {
  const char* s = NULL;
  switch (t) {
    case Metaspace::StandardMetaspaceType: s = "Standard"; break;
    case Metaspace::BootMetaspaceType: s = "Boot"; break;
    case Metaspace::AnonymousMetaspaceType: s = "Anonymous"; break;
    case Metaspace::ReflectionMetaspaceType: s = "Reflection"; break;
    default: ShouldNotReachHere();
  }
  return s;
}

volatile size_t MetaspaceGC::_capacity_until_GC = 0;
uint MetaspaceGC::_shrink_factor = 0;
bool MetaspaceGC::_should_concurrent_collect = false;

// BlockFreelist methods

// VirtualSpaceNode methods

// MetaspaceGC methods

// VM_CollectForMetadataAllocation is the vm operation used to GC.
// Within the VM operation after the GC the attempt to allocate the metadata
// should succeed.  If the GC did not free enough space for the metaspace
// allocation, the HWM is increased so that another virtualspace will be
// allocated for the metadata.  With perm gen the increase in the perm
// gen had bounds, MinMetaspaceExpansion and MaxMetaspaceExpansion.  The
// metaspace policy uses those as the small and large steps for the HWM.
//
// After the GC the compute_new_size() for MetaspaceGC is called to
// resize the capacity of the metaspaces.  The current implementation
// is based on the flags MinMetaspaceFreeRatio and MaxMetaspaceFreeRatio used
// to resize the Java heap by some GC's.  New flags can be implemented
// if really needed.  MinMetaspaceFreeRatio is used to calculate how much
// free space is desirable in the metaspace capacity to decide how much
// to increase the HWM.  MaxMetaspaceFreeRatio is used to decide how much
// free space is desirable in the metaspace capacity before decreasing
// the HWM.

// Calculate the amount to increase the high water mark (HWM).
// Increase by a minimum amount (MinMetaspaceExpansion) so that
// another expansion is not requested too soon.  If that is not
// enough to satisfy the allocation, increase by MaxMetaspaceExpansion.
// If that is still not enough, expand by the size of the allocation
// plus some.
size_t MetaspaceGC::delta_capacity_until_GC(size_t bytes) {
  size_t min_delta = MinMetaspaceExpansion;
  size_t max_delta = MaxMetaspaceExpansion;
  size_t delta = align_up(bytes, Metaspace::commit_alignment());

  if (delta <= min_delta) {
    delta = min_delta;
  } else if (delta <= max_delta) {
    // Don't want to hit the high water mark on the next
    // allocation so make the delta greater than just enough
    // for this allocation.
    delta = max_delta;
  } else {
    // This allocation is large but the next ones are probably not
    // so increase by the minimum.
    delta = delta + min_delta;
  }

  assert_is_aligned(delta, Metaspace::commit_alignment());

  return delta;
}

size_t MetaspaceGC::capacity_until_GC() {
  size_t value = OrderAccess::load_acquire(&_capacity_until_GC);
  assert(value >= MetaspaceSize, "Not initialized properly?");
  return value;
}

// Try to increase the _capacity_until_GC limit counter by v bytes.
// Returns true if it succeeded. It may fail if either another thread
// concurrently increased the limit or the new limit would be larger
// than MaxMetaspaceSize.
// On success, optionally returns new and old metaspace capacity in
// new_cap_until_GC and old_cap_until_GC respectively.
// On error, optionally sets can_retry to indicate whether if there is
// actually enough space remaining to satisfy the request.
bool MetaspaceGC::inc_capacity_until_GC(size_t v, size_t* new_cap_until_GC, size_t* old_cap_until_GC, bool* can_retry) {
  assert_is_aligned(v, Metaspace::commit_alignment());

  size_t old_capacity_until_GC = _capacity_until_GC;
  size_t new_value = old_capacity_until_GC + v;

  if (new_value < old_capacity_until_GC) {
    // The addition wrapped around, set new_value to aligned max value.
    new_value = align_down(max_uintx, Metaspace::commit_alignment());
  }

  if (new_value > MaxMetaspaceSize) {
    if (can_retry != NULL) {
      *can_retry = false;
    }
    return false;
  }

  if (can_retry != NULL) {
    *can_retry = true;
  }
  size_t prev_value = Atomic::cmpxchg(new_value, &_capacity_until_GC, old_capacity_until_GC);

  if (old_capacity_until_GC != prev_value) {
    return false;
  }

  if (new_cap_until_GC != NULL) {
    *new_cap_until_GC = new_value;
  }
  if (old_cap_until_GC != NULL) {
    *old_cap_until_GC = old_capacity_until_GC;
  }
  return true;
}

size_t MetaspaceGC::dec_capacity_until_GC(size_t v) {
  assert_is_aligned(v, Metaspace::commit_alignment());

  return Atomic::sub(v, &_capacity_until_GC);
}

void MetaspaceGC::initialize() {
  // Set the high-water mark to MaxMetapaceSize during VM initializaton since
  // we can't do a GC during initialization.
  _capacity_until_GC = MaxMetaspaceSize;
}

void MetaspaceGC::post_initialize() {
  // Reset the high-water mark once the VM initialization is done.
  _capacity_until_GC = MAX2(MetaspaceUtils::committed_bytes(), MetaspaceSize);
}

bool MetaspaceGC::can_expand(size_t word_size, bool is_class) {
  // Check if the compressed class space is full.
  if (is_class && Metaspace::using_class_space()) {
    size_t class_committed = MetaspaceUtils::committed_bytes(Metaspace::ClassType);
    if (class_committed + word_size * BytesPerWord > CompressedClassSpaceSize) {
      log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (CompressedClassSpaceSize = " SIZE_FORMAT " words)",
                (is_class ? "class" : "non-class"), word_size, CompressedClassSpaceSize / sizeof(MetaWord));
      return false;
    }
  }

  // Check if the user has imposed a limit on the metaspace memory.
  size_t committed_bytes = MetaspaceUtils::committed_bytes();
  if (committed_bytes + word_size * BytesPerWord > MaxMetaspaceSize) {
    log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (MaxMetaspaceSize = " SIZE_FORMAT " words)",
              (is_class ? "class" : "non-class"), word_size, MaxMetaspaceSize / sizeof(MetaWord));
    return false;
  }

  return true;
}

size_t MetaspaceGC::allowed_expansion() {
  size_t committed_bytes = MetaspaceUtils::committed_bytes();
  size_t capacity_until_gc = capacity_until_GC();

  assert(capacity_until_gc >= committed_bytes,
         "capacity_until_gc: " SIZE_FORMAT " < committed_bytes: " SIZE_FORMAT,
         capacity_until_gc, committed_bytes);

  size_t left_until_max  = MaxMetaspaceSize - committed_bytes;
  size_t left_until_GC = capacity_until_gc - committed_bytes;
  size_t left_to_commit = MIN2(left_until_GC, left_until_max);
  log_trace(gc, metaspace, freelist)("allowed expansion words: " SIZE_FORMAT
            " (left_until_max: " SIZE_FORMAT ", left_until_GC: " SIZE_FORMAT ".",
            left_to_commit / BytesPerWord, left_until_max / BytesPerWord, left_until_GC / BytesPerWord);

  return left_to_commit / BytesPerWord;
}

void MetaspaceGC::compute_new_size() {
  assert(_shrink_factor <= 100, "invalid shrink factor");
  uint current_shrink_factor = _shrink_factor;
  _shrink_factor = 0;

  // Using committed_bytes() for used_after_gc is an overestimation, since the
  // chunk free lists are included in committed_bytes() and the memory in an
  // un-fragmented chunk free list is available for future allocations.
  // However, if the chunk free lists becomes fragmented, then the memory may
  // not be available for future allocations and the memory is therefore "in use".
  // Including the chunk free lists in the definition of "in use" is therefore
  // necessary. Not including the chunk free lists can cause capacity_until_GC to
  // shrink below committed_bytes() and this has caused serious bugs in the past.
  const size_t used_after_gc = MetaspaceUtils::committed_bytes();
  const size_t capacity_until_GC = MetaspaceGC::capacity_until_GC();

  const double minimum_free_percentage = MinMetaspaceFreeRatio / 100.0;
  const double maximum_used_percentage = 1.0 - minimum_free_percentage;

  const double min_tmp = used_after_gc / maximum_used_percentage;
  size_t minimum_desired_capacity =
    (size_t)MIN2(min_tmp, double(MaxMetaspaceSize));
  // Don't shrink less than the initial generation size
  minimum_desired_capacity = MAX2(minimum_desired_capacity,
                                  MetaspaceSize);

  log_trace(gc, metaspace)("MetaspaceGC::compute_new_size: ");
  log_trace(gc, metaspace)("    minimum_free_percentage: %6.2f  maximum_used_percentage: %6.2f",
                           minimum_free_percentage, maximum_used_percentage);
  log_trace(gc, metaspace)("     used_after_gc       : %6.1fKB", used_after_gc / (double) K);


  size_t shrink_bytes = 0;
  if (capacity_until_GC < minimum_desired_capacity) {
    // If we have less capacity below the metaspace HWM, then
    // increment the HWM.
    size_t expand_bytes = minimum_desired_capacity - capacity_until_GC;
    expand_bytes = align_up(expand_bytes, Metaspace::commit_alignment());
    // Don't expand unless it's significant
    if (expand_bytes >= MinMetaspaceExpansion) {
      size_t new_capacity_until_GC = 0;
      bool succeeded = MetaspaceGC::inc_capacity_until_GC(expand_bytes, &new_capacity_until_GC);
      assert(succeeded, "Should always succesfully increment HWM when at safepoint");

      Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
                                               new_capacity_until_GC,
                                               MetaspaceGCThresholdUpdater::ComputeNewSize);
      log_trace(gc, metaspace)("    expanding:  minimum_desired_capacity: %6.1fKB  expand_bytes: %6.1fKB  MinMetaspaceExpansion: %6.1fKB  new metaspace HWM:  %6.1fKB",
                               minimum_desired_capacity / (double) K,
                               expand_bytes / (double) K,
                               MinMetaspaceExpansion / (double) K,
                               new_capacity_until_GC / (double) K);
    }
    return;
  }

  // No expansion, now see if we want to shrink
  // We would never want to shrink more than this
  assert(capacity_until_GC >= minimum_desired_capacity,
         SIZE_FORMAT " >= " SIZE_FORMAT,
         capacity_until_GC, minimum_desired_capacity);
  size_t max_shrink_bytes = capacity_until_GC - minimum_desired_capacity;

  // Should shrinking be considered?
  if (MaxMetaspaceFreeRatio < 100) {
    const double maximum_free_percentage = MaxMetaspaceFreeRatio / 100.0;
    const double minimum_used_percentage = 1.0 - maximum_free_percentage;
    const double max_tmp = used_after_gc / minimum_used_percentage;
    size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(MaxMetaspaceSize));
    maximum_desired_capacity = MAX2(maximum_desired_capacity,
                                    MetaspaceSize);
    log_trace(gc, metaspace)("    maximum_free_percentage: %6.2f  minimum_used_percentage: %6.2f",
                             maximum_free_percentage, minimum_used_percentage);
    log_trace(gc, metaspace)("    minimum_desired_capacity: %6.1fKB  maximum_desired_capacity: %6.1fKB",
                             minimum_desired_capacity / (double) K, maximum_desired_capacity / (double) K);

    assert(minimum_desired_capacity <= maximum_desired_capacity,
           "sanity check");

    if (capacity_until_GC > maximum_desired_capacity) {
      // Capacity too large, compute shrinking size
      shrink_bytes = capacity_until_GC - maximum_desired_capacity;
      // We don't want shrink all the way back to initSize if people call
      // System.gc(), because some programs do that between "phases" and then
      // we'd just have to grow the heap up again for the next phase.  So we
      // damp the shrinking: 0% on the first call, 10% on the second call, 40%
      // on the third call, and 100% by the fourth call.  But if we recompute
      // size without shrinking, it goes back to 0%.
      shrink_bytes = shrink_bytes / 100 * current_shrink_factor;

      shrink_bytes = align_down(shrink_bytes, Metaspace::commit_alignment());

      assert(shrink_bytes <= max_shrink_bytes,
             "invalid shrink size " SIZE_FORMAT " not <= " SIZE_FORMAT,
             shrink_bytes, max_shrink_bytes);
      if (current_shrink_factor == 0) {
        _shrink_factor = 10;
      } else {
        _shrink_factor = MIN2(current_shrink_factor * 4, (uint) 100);
      }
      log_trace(gc, metaspace)("    shrinking:  initThreshold: %.1fK  maximum_desired_capacity: %.1fK",
                               MetaspaceSize / (double) K, maximum_desired_capacity / (double) K);
      log_trace(gc, metaspace)("    shrink_bytes: %.1fK  current_shrink_factor: %d  new shrink factor: %d  MinMetaspaceExpansion: %.1fK",
                               shrink_bytes / (double) K, current_shrink_factor, _shrink_factor, MinMetaspaceExpansion / (double) K);
    }
  }

  // Don't shrink unless it's significant
  if (shrink_bytes >= MinMetaspaceExpansion &&
      ((capacity_until_GC - shrink_bytes) >= MetaspaceSize)) {
    size_t new_capacity_until_GC = MetaspaceGC::dec_capacity_until_GC(shrink_bytes);
    Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
                                             new_capacity_until_GC,
                                             MetaspaceGCThresholdUpdater::ComputeNewSize);
  }
}

// MetaspaceUtils
size_t MetaspaceUtils::_capacity_words [Metaspace:: MetadataTypeCount] = {0, 0};
size_t MetaspaceUtils::_overhead_words [Metaspace:: MetadataTypeCount] = {0, 0};
volatile size_t MetaspaceUtils::_used_words [Metaspace:: MetadataTypeCount] = {0, 0};

// Collect used metaspace statistics. This involves walking the CLDG. The resulting
// output will be the accumulated values for all live metaspaces.
// Note: method does not do any locking.
void MetaspaceUtils::collect_statistics(ClassLoaderMetaspaceStatistics* out) {
  out->reset();
  ClassLoaderDataGraphMetaspaceIterator iter;
   while (iter.repeat()) {
     ClassLoaderMetaspace* msp = iter.get_next();
     if (msp != NULL) {
       msp->add_to_statistics(out);
     }
   }
}

size_t MetaspaceUtils::free_in_vs_bytes(Metaspace::MetadataType mdtype) {
  VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
  return list == NULL ? 0 : list->free_bytes();
}

size_t MetaspaceUtils::free_in_vs_bytes() {
  return free_in_vs_bytes(Metaspace::ClassType) + free_in_vs_bytes(Metaspace::NonClassType);
}

static void inc_stat_nonatomically(size_t* pstat, size_t words) {
  assert_lock_strong(MetaspaceExpand_lock);
  (*pstat) += words;
}

static void dec_stat_nonatomically(size_t* pstat, size_t words) {
  assert_lock_strong(MetaspaceExpand_lock);
  const size_t size_now = *pstat;
  assert(size_now >= words, "About to decrement counter below zero "
         "(current value: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ".",
         size_now, words);
  *pstat = size_now - words;
}

static void inc_stat_atomically(volatile size_t* pstat, size_t words) {
  Atomic::add(words, pstat);
}

static void dec_stat_atomically(volatile size_t* pstat, size_t words) {
  const size_t size_now = *pstat;
  assert(size_now >= words, "About to decrement counter below zero "
         "(current value: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ".",
         size_now, words);
  Atomic::sub(words, pstat);
}

void MetaspaceUtils::dec_capacity(Metaspace::MetadataType mdtype, size_t words) {
  dec_stat_nonatomically(&_capacity_words[mdtype], words);
}
void MetaspaceUtils::inc_capacity(Metaspace::MetadataType mdtype, size_t words) {
  inc_stat_nonatomically(&_capacity_words[mdtype], words);
}
void MetaspaceUtils::dec_used(Metaspace::MetadataType mdtype, size_t words) {
  dec_stat_atomically(&_used_words[mdtype], words);
}
void MetaspaceUtils::inc_used(Metaspace::MetadataType mdtype, size_t words) {
  inc_stat_atomically(&_used_words[mdtype], words);
}
void MetaspaceUtils::dec_overhead(Metaspace::MetadataType mdtype, size_t words) {
  dec_stat_nonatomically(&_overhead_words[mdtype], words);
}
void MetaspaceUtils::inc_overhead(Metaspace::MetadataType mdtype, size_t words) {
  inc_stat_nonatomically(&_overhead_words[mdtype], words);
}

size_t MetaspaceUtils::reserved_bytes(Metaspace::MetadataType mdtype) {
  VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
  return list == NULL ? 0 : list->reserved_bytes();
}

size_t MetaspaceUtils::committed_bytes(Metaspace::MetadataType mdtype) {
  VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
  return list == NULL ? 0 : list->committed_bytes();
}

size_t MetaspaceUtils::min_chunk_size_words() { return Metaspace::first_chunk_word_size(); }

size_t MetaspaceUtils::free_chunks_total_words(Metaspace::MetadataType mdtype) {
  ChunkManager* chunk_manager = Metaspace::get_chunk_manager(mdtype);
  if (chunk_manager == NULL) {
    return 0;
  }
  chunk_manager->slow_verify();
  return chunk_manager->free_chunks_total_words();
}

size_t MetaspaceUtils::free_chunks_total_bytes(Metaspace::MetadataType mdtype) {
  return free_chunks_total_words(mdtype) * BytesPerWord;
}

size_t MetaspaceUtils::free_chunks_total_words() {
  return free_chunks_total_words(Metaspace::ClassType) +
         free_chunks_total_words(Metaspace::NonClassType);
}

size_t MetaspaceUtils::free_chunks_total_bytes() {
  return free_chunks_total_words() * BytesPerWord;
}

bool MetaspaceUtils::has_chunk_free_list(Metaspace::MetadataType mdtype) {
  return Metaspace::get_chunk_manager(mdtype) != NULL;
}

MetaspaceChunkFreeListSummary MetaspaceUtils::chunk_free_list_summary(Metaspace::MetadataType mdtype) {
  if (!has_chunk_free_list(mdtype)) {
    return MetaspaceChunkFreeListSummary();
  }

  const ChunkManager* cm = Metaspace::get_chunk_manager(mdtype);
  return cm->chunk_free_list_summary();
}

void MetaspaceUtils::print_metaspace_change(size_t prev_metadata_used) {
  log_info(gc, metaspace)("Metaspace: "  SIZE_FORMAT "K->" SIZE_FORMAT "K("  SIZE_FORMAT "K)",
                          prev_metadata_used/K, used_bytes()/K, reserved_bytes()/K);
}

void MetaspaceUtils::print_on(outputStream* out) {
  Metaspace::MetadataType nct = Metaspace::NonClassType;

  out->print_cr(" Metaspace       "
                "used "      SIZE_FORMAT "K, "
                "capacity "  SIZE_FORMAT "K, "
                "committed " SIZE_FORMAT "K, "
                "reserved "  SIZE_FORMAT "K",
                used_bytes()/K,
                capacity_bytes()/K,
                committed_bytes()/K,
                reserved_bytes()/K);

  if (Metaspace::using_class_space()) {
    Metaspace::MetadataType ct = Metaspace::ClassType;
    out->print_cr("  class space    "
                  "used "      SIZE_FORMAT "K, "
                  "capacity "  SIZE_FORMAT "K, "
                  "committed " SIZE_FORMAT "K, "
                  "reserved "  SIZE_FORMAT "K",
                  used_bytes(ct)/K,
                  capacity_bytes(ct)/K,
                  committed_bytes(ct)/K,
                  reserved_bytes(ct)/K);
  }
}


void MetaspaceUtils::print_vs(outputStream* out, size_t scale) {
  const size_t reserved_nonclass_words = reserved_bytes(Metaspace::NonClassType) / sizeof(MetaWord);
  const size_t committed_nonclass_words = committed_bytes(Metaspace::NonClassType) / sizeof(MetaWord);
  {
    if (Metaspace::using_class_space()) {
      out->print("  Non-class space:  ");
    }
    print_scaled_words(out, reserved_nonclass_words, scale, 7);
    out->print(" reserved, ");
    print_scaled_words_and_percentage(out, committed_nonclass_words, reserved_nonclass_words, scale, 7);
    out->print_cr(" committed ");

    if (Metaspace::using_class_space()) {
      const size_t reserved_class_words = reserved_bytes(Metaspace::ClassType) / sizeof(MetaWord);
      const size_t committed_class_words = committed_bytes(Metaspace::ClassType) / sizeof(MetaWord);
      out->print("      Class space:  ");
      print_scaled_words(out, reserved_class_words, scale, 7);
      out->print(" reserved, ");
      print_scaled_words_and_percentage(out, committed_class_words, reserved_class_words, scale, 7);
      out->print_cr(" committed ");

      const size_t reserved_words = reserved_nonclass_words + reserved_class_words;
      const size_t committed_words = committed_nonclass_words + committed_class_words;
      out->print("             Both:  ");
      print_scaled_words(out, reserved_words, scale, 7);
      out->print(" reserved, ");
      print_scaled_words_and_percentage(out, committed_words, reserved_words, scale, 7);
      out->print_cr(" committed ");
    }
  }
}

static void print_basic_switches(outputStream* out, size_t scale) {
  out->print("MaxMetaspaceSize: ");
  if (MaxMetaspaceSize >= (max_uintx) - (2 * os::vm_page_size())) {
    // aka "very big". Default is max_uintx, but due to rounding in arg parsing the real
    // value is smaller.
    out->print("unlimited");
  } else {
    print_human_readable_size(out, MaxMetaspaceSize, scale);
  }
  out->cr();
  if (Metaspace::using_class_space()) {
    out->print("CompressedClassSpaceSize: ");
    print_human_readable_size(out, CompressedClassSpaceSize, scale);
  } else {
    out->print("No class space");
  }
  out->cr();
  out->print("Initial GC threshold: ");
  print_human_readable_size(out, MetaspaceSize, scale);
  out->cr();
  out->print("Current GC threshold: ");
  print_human_readable_size(out, MetaspaceGC::capacity_until_GC(), scale);
  out->cr();
  out->print_cr("CDS: %s", (UseSharedSpaces ? "on" : (DumpSharedSpaces ? "dump" : "off")));
}

// This will print out a basic metaspace usage report but
// unlike print_report() is guaranteed not to lock or to walk the CLDG.
void MetaspaceUtils::print_basic_report(outputStream* out, size_t scale) {

  if (!Metaspace::initialized()) {
    out->print_cr("Metaspace not yet initialized.");
    return;
  }

  out->cr();
  out->print_cr("Usage:");

  if (Metaspace::using_class_space()) {
    out->print("  Non-class:  ");
  }

  // In its most basic form, we do not require walking the CLDG. Instead, just print the running totals from
  // MetaspaceUtils.
  const size_t cap_nc = MetaspaceUtils::capacity_words(Metaspace::NonClassType);
  const size_t overhead_nc = MetaspaceUtils::overhead_words(Metaspace::NonClassType);
  const size_t used_nc = MetaspaceUtils::used_words(Metaspace::NonClassType);
  const size_t free_and_waste_nc = cap_nc - overhead_nc - used_nc;

  print_scaled_words(out, cap_nc, scale, 5);
  out->print(" capacity, ");
  print_scaled_words_and_percentage(out, used_nc, cap_nc, scale, 5);
  out->print(" used, ");
  print_scaled_words_and_percentage(out, free_and_waste_nc, cap_nc, scale, 5);
  out->print(" free+waste, ");
  print_scaled_words_and_percentage(out, overhead_nc, cap_nc, scale, 5);
  out->print(" overhead. ");
  out->cr();

  if (Metaspace::using_class_space()) {
    const size_t cap_c = MetaspaceUtils::capacity_words(Metaspace::ClassType);
    const size_t overhead_c = MetaspaceUtils::overhead_words(Metaspace::ClassType);
    const size_t used_c = MetaspaceUtils::used_words(Metaspace::ClassType);
    const size_t free_and_waste_c = cap_c - overhead_c - used_c;
    out->print("      Class:  ");
    print_scaled_words(out, cap_c, scale, 5);
    out->print(" capacity, ");
    print_scaled_words_and_percentage(out, used_c, cap_c, scale, 5);
    out->print(" used, ");
    print_scaled_words_and_percentage(out, free_and_waste_c, cap_c, scale, 5);
    out->print(" free+waste, ");
    print_scaled_words_and_percentage(out, overhead_c, cap_c, scale, 5);
    out->print(" overhead. ");
    out->cr();

    out->print("       Both:  ");
    const size_t cap = cap_nc + cap_c;

    print_scaled_words(out, cap, scale, 5);
    out->print(" capacity, ");
    print_scaled_words_and_percentage(out, used_nc + used_c, cap, scale, 5);
    out->print(" used, ");
    print_scaled_words_and_percentage(out, free_and_waste_nc + free_and_waste_c, cap, scale, 5);
    out->print(" free+waste, ");
    print_scaled_words_and_percentage(out, overhead_nc + overhead_c, cap, scale, 5);
    out->print(" overhead. ");
    out->cr();
  }

  out->cr();
  out->print_cr("Virtual space:");

  print_vs(out, scale);

  out->cr();
  out->print_cr("Chunk freelists:");

  if (Metaspace::using_class_space()) {
    out->print("   Non-Class:  ");
  }
  print_human_readable_size(out, Metaspace::chunk_manager_metadata()->free_chunks_total_bytes(), scale);
  out->cr();
  if (Metaspace::using_class_space()) {
    out->print("       Class:  ");
    print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_bytes(), scale);
    out->cr();
    out->print("        Both:  ");
    print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_bytes() +
                              Metaspace::chunk_manager_metadata()->free_chunks_total_bytes(), scale);
    out->cr();
  }

  out->cr();

  // Print basic settings
  print_basic_switches(out, scale);

  out->cr();

}

void MetaspaceUtils::print_report(outputStream* out, size_t scale, int flags) {

  if (!Metaspace::initialized()) {
    out->print_cr("Metaspace not yet initialized.");
    return;
  }

  const bool print_loaders = (flags & rf_show_loaders) > 0;
  const bool print_classes = (flags & rf_show_classes) > 0;
  const bool print_by_chunktype = (flags & rf_break_down_by_chunktype) > 0;
  const bool print_by_spacetype = (flags & rf_break_down_by_spacetype) > 0;

  // Some report options require walking the class loader data graph.
  PrintCLDMetaspaceInfoClosure cl(out, scale, print_loaders, print_classes, print_by_chunktype);
  if (print_loaders) {
    out->cr();
    out->print_cr("Usage per loader:");
    out->cr();
  }

  ClassLoaderDataGraph::cld_do(&cl); // collect data and optionally print

  // Print totals, broken up by space type.
  if (print_by_spacetype) {
    out->cr();
    out->print_cr("Usage per space type:");
    out->cr();
    for (int space_type = (int)Metaspace::ZeroMetaspaceType;
         space_type < (int)Metaspace::MetaspaceTypeCount; space_type ++)
    {
      uintx num_loaders = cl._num_loaders_by_spacetype[space_type];
      uintx num_classes = cl._num_classes_by_spacetype[space_type];
      out->print("%s - " UINTX_FORMAT " %s",
        space_type_name((Metaspace::MetaspaceType)space_type),
        num_loaders, loaders_plural(num_loaders));
      if (num_classes > 0) {
        out->print(", ");
        print_number_of_classes(out, num_classes, cl._num_classes_shared_by_spacetype[space_type]);
        out->print(":");
        cl._stats_by_spacetype[space_type].print_on(out, scale, print_by_chunktype);
      } else {
        out->print(".");
        out->cr();
      }
      out->cr();
    }
  }

  // Print totals for in-use data:
  out->cr();
  {
    uintx num_loaders = cl._num_loaders;
    out->print("Total Usage - " UINTX_FORMAT " %s, ",
      num_loaders, loaders_plural(num_loaders));
    print_number_of_classes(out, cl._num_classes, cl._num_classes_shared);
    out->print(":");
    cl._stats_total.print_on(out, scale, print_by_chunktype);
    out->cr();
  }

  // -- Print Virtual space.
  out->cr();
  out->print_cr("Virtual space:");

  print_vs(out, scale);

  // -- Print VirtualSpaceList details.
  if ((flags & rf_show_vslist) > 0) {
    out->cr();
    out->print_cr("Virtual space list%s:", Metaspace::using_class_space() ? "s" : "");

    if (Metaspace::using_class_space()) {
      out->print_cr("   Non-Class:");
    }
    Metaspace::space_list()->print_on(out, scale);
    if (Metaspace::using_class_space()) {
      out->print_cr("       Class:");
      Metaspace::class_space_list()->print_on(out, scale);
    }
  }
  out->cr();

  // -- Print VirtualSpaceList map.
  if ((flags & rf_show_vsmap) > 0) {
    out->cr();
    out->print_cr("Virtual space map:");

    if (Metaspace::using_class_space()) {
      out->print_cr("   Non-Class:");
    }
    Metaspace::space_list()->print_map(out);
    if (Metaspace::using_class_space()) {
      out->print_cr("       Class:");
      Metaspace::class_space_list()->print_map(out);
    }
  }
  out->cr();

  // -- Print Freelists (ChunkManager) details
  out->cr();
  out->print_cr("Chunk freelist%s:", Metaspace::using_class_space() ? "s" : "");

  ChunkManagerStatistics non_class_cm_stat;
  Metaspace::chunk_manager_metadata()->collect_statistics(&non_class_cm_stat);

  if (Metaspace::using_class_space()) {
    out->print_cr("   Non-Class:");
  }
  non_class_cm_stat.print_on(out, scale);

  if (Metaspace::using_class_space()) {
    ChunkManagerStatistics class_cm_stat;
    Metaspace::chunk_manager_class()->collect_statistics(&class_cm_stat);
    out->print_cr("       Class:");
    class_cm_stat.print_on(out, scale);
  }

  // As a convenience, print a summary of common waste.
  out->cr();
  out->print("Waste ");
  // For all wastages, print percentages from total. As total use the total size of memory committed for metaspace.
  const size_t committed_words = committed_bytes() / BytesPerWord;

  out->print("(percentages refer to total committed size ");
  print_scaled_words(out, committed_words, scale);
  out->print_cr("):");

  // Print space committed but not yet used by any class loader
  const size_t unused_words_in_vs = MetaspaceUtils::free_in_vs_bytes() / BytesPerWord;
  out->print("              Committed unused: ");
  print_scaled_words_and_percentage(out, unused_words_in_vs, committed_words, scale, 6);
  out->cr();

  // Print waste for in-use chunks.
  UsedChunksStatistics ucs_nonclass = cl._stats_total.nonclass_sm_stats().totals();
  UsedChunksStatistics ucs_class = cl._stats_total.class_sm_stats().totals();
  UsedChunksStatistics ucs_all;
  ucs_all.add(ucs_nonclass);
  ucs_all.add(ucs_class);

  out->print("        Waste in chunks in use: ");
  print_scaled_words_and_percentage(out, ucs_all.waste(), committed_words, scale, 6);
  out->cr();
  out->print("         Free in chunks in use: ");
  print_scaled_words_and_percentage(out, ucs_all.free(), committed_words, scale, 6);
  out->cr();
  out->print("     Overhead in chunks in use: ");
  print_scaled_words_and_percentage(out, ucs_all.overhead(), committed_words, scale, 6);
  out->cr();

  // Print waste in free chunks.
  const size_t total_capacity_in_free_chunks =
      Metaspace::chunk_manager_metadata()->free_chunks_total_words() +
     (Metaspace::using_class_space() ? Metaspace::chunk_manager_class()->free_chunks_total_words() : 0);
  out->print("                In free chunks: ");
  print_scaled_words_and_percentage(out, total_capacity_in_free_chunks, committed_words, scale, 6);
  out->cr();

  // Print waste in deallocated blocks.
  const uintx free_blocks_num =
      cl._stats_total.nonclass_sm_stats().free_blocks_num() +
      cl._stats_total.class_sm_stats().free_blocks_num();
  const size_t free_blocks_cap_words =
      cl._stats_total.nonclass_sm_stats().free_blocks_cap_words() +
      cl._stats_total.class_sm_stats().free_blocks_cap_words();
  out->print("Deallocated from chunks in use: ");
  print_scaled_words_and_percentage(out, free_blocks_cap_words, committed_words, scale, 6);
  out->print(" (" UINTX_FORMAT " blocks)", free_blocks_num);
  out->cr();

  // Print total waste.
  const size_t total_waste = ucs_all.waste() + ucs_all.free() + ucs_all.overhead() + total_capacity_in_free_chunks
      + free_blocks_cap_words + unused_words_in_vs;
  out->print("                       -total-: ");
  print_scaled_words_and_percentage(out, total_waste, committed_words, scale, 6);
  out->cr();

  // Print internal statistics
#ifdef ASSERT
  out->cr();
  out->cr();
  out->print_cr("Internal statistics:");
  out->cr();
  out->print_cr("Number of allocations: " UINTX_FORMAT ".", g_internal_statistics.num_allocs);
  out->print_cr("Number of space births: " UINTX_FORMAT ".", g_internal_statistics.num_metaspace_births);
  out->print_cr("Number of space deaths: " UINTX_FORMAT ".", g_internal_statistics.num_metaspace_deaths);
  out->print_cr("Number of virtual space node births: " UINTX_FORMAT ".", g_internal_statistics.num_vsnodes_created);
  out->print_cr("Number of virtual space node deaths: " UINTX_FORMAT ".", g_internal_statistics.num_vsnodes_purged);
  out->print_cr("Number of times virtual space nodes were expanded: " UINTX_FORMAT ".", g_internal_statistics.num_committed_space_expanded);
  out->print_cr("Number of deallocations: " UINTX_FORMAT " (" UINTX_FORMAT " external).", g_internal_statistics.num_deallocs, g_internal_statistics.num_external_deallocs);
  out->print_cr("Allocations from deallocated blocks: " UINTX_FORMAT ".", g_internal_statistics.num_allocs_from_deallocated_blocks);
  out->cr();
#endif

  // Print some interesting settings
  out->cr();
  out->cr();
  print_basic_switches(out, scale);

  out->cr();
  out->print("InitialBootClassLoaderMetaspaceSize: ");
  print_human_readable_size(out, InitialBootClassLoaderMetaspaceSize, scale);

  out->cr();
  out->cr();

} // MetaspaceUtils::print_report()

// Prints an ASCII representation of the given space.
void MetaspaceUtils::print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype) {
  MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
  const bool for_class = mdtype == Metaspace::ClassType ? true : false;
  VirtualSpaceList* const vsl = for_class ? Metaspace::class_space_list() : Metaspace::space_list();
  if (vsl != NULL) {
    if (for_class) {
      if (!Metaspace::using_class_space()) {
        out->print_cr("No Class Space.");
        return;
      }
      out->print_raw("---- Metaspace Map (Class Space) ----");
    } else {
      out->print_raw("---- Metaspace Map (Non-Class Space) ----");
    }
    // Print legend:
    out->cr();
    out->print_cr("Chunk Types (uppercase chunks are in use): x-specialized, s-small, m-medium, h-humongous.");
    out->cr();
    VirtualSpaceList* const vsl = for_class ? Metaspace::class_space_list() : Metaspace::space_list();
    vsl->print_map(out);
    out->cr();
  }
}

void MetaspaceUtils::verify_free_chunks() {
  Metaspace::chunk_manager_metadata()->verify();
  if (Metaspace::using_class_space()) {
    Metaspace::chunk_manager_class()->verify();
  }
}

void MetaspaceUtils::verify_metrics() {
#ifdef ASSERT
  // Please note: there are time windows where the internal counters are out of sync with
  // reality. For example, when a newly created ClassLoaderMetaspace creates its first chunk -
  // the ClassLoaderMetaspace is not yet attached to its ClassLoaderData object and hence will
  // not be counted when iterating the CLDG. So be careful when you call this method.
  ClassLoaderMetaspaceStatistics total_stat;
  collect_statistics(&total_stat);
  UsedChunksStatistics nonclass_chunk_stat = total_stat.nonclass_sm_stats().totals();
  UsedChunksStatistics class_chunk_stat = total_stat.class_sm_stats().totals();

  bool mismatch = false;
  for (int i = 0; i < Metaspace::MetadataTypeCount; i ++) {
    Metaspace::MetadataType mdtype = (Metaspace::MetadataType)i;
    UsedChunksStatistics chunk_stat = total_stat.sm_stats(mdtype).totals();
    if (capacity_words(mdtype) != chunk_stat.cap() ||
        used_words(mdtype) != chunk_stat.used() ||
        overhead_words(mdtype) != chunk_stat.overhead()) {
      mismatch = true;
      tty->print_cr("MetaspaceUtils::verify_metrics: counter mismatch for mdtype=%u:", mdtype);
      tty->print_cr("Expected cap " SIZE_FORMAT ", used " SIZE_FORMAT ", overhead " SIZE_FORMAT ".",
                    capacity_words(mdtype), used_words(mdtype), overhead_words(mdtype));
      tty->print_cr("Got cap " SIZE_FORMAT ", used " SIZE_FORMAT ", overhead " SIZE_FORMAT ".",
                    chunk_stat.cap(), chunk_stat.used(), chunk_stat.overhead());
      tty->flush();
    }
  }
  assert(mismatch == false, "MetaspaceUtils::verify_metrics: counter mismatch.");
#endif
}

// Utils to check if a pointer or range is part of a committed metaspace region.
metaspace::VirtualSpaceNode* MetaspaceUtils::find_enclosing_virtual_space(const void* p) {
  VirtualSpaceNode* vsn = Metaspace::space_list()->find_enclosing_space(p);
  if (Metaspace::using_class_space() && vsn == NULL) {
    vsn = Metaspace::class_space_list()->find_enclosing_space(p);
  }
  return vsn;
}

bool MetaspaceUtils::is_in_committed(const void* p) {
#if INCLUDE_CDS
  if (UseSharedSpaces) {
    for (int idx = MetaspaceShared::ro; idx <= MetaspaceShared::mc; idx++) {
      if (FileMapInfo::current_info()->is_in_shared_region(p, idx)) {
        return true;
      }
    }
  }
#endif
  return find_enclosing_virtual_space(p) != NULL;
}

bool MetaspaceUtils::is_range_in_committed(const void* from, const void* to) {
#if INCLUDE_CDS
  if (UseSharedSpaces) {
    for (int idx = MetaspaceShared::ro; idx <= MetaspaceShared::mc; idx++) {
      if (FileMapInfo::current_info()->is_in_shared_region(from, idx)) {
        return FileMapInfo::current_info()->is_in_shared_region(to, idx);
      }
    }
  }
#endif
  VirtualSpaceNode* vsn = find_enclosing_virtual_space(from);
  return (vsn != NULL) && vsn->contains(to);
}


// Metaspace methods

size_t Metaspace::_first_chunk_word_size = 0;
size_t Metaspace::_first_class_chunk_word_size = 0;

size_t Metaspace::_commit_alignment = 0;
size_t Metaspace::_reserve_alignment = 0;

VirtualSpaceList* Metaspace::_space_list = NULL;
VirtualSpaceList* Metaspace::_class_space_list = NULL;

ChunkManager* Metaspace::_chunk_manager_metadata = NULL;
ChunkManager* Metaspace::_chunk_manager_class = NULL;

bool Metaspace::_initialized = false;

#define VIRTUALSPACEMULTIPLIER 2

#ifdef _LP64
static const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);

void Metaspace::set_narrow_klass_base_and_shift(address metaspace_base, address cds_base) {
  assert(!DumpSharedSpaces, "narrow_klass is set by MetaspaceShared class.");
  // Figure out the narrow_klass_base and the narrow_klass_shift.  The
  // narrow_klass_base is the lower of the metaspace base and the cds base
  // (if cds is enabled).  The narrow_klass_shift depends on the distance
  // between the lower base and higher address.
  address lower_base;
  address higher_address;
#if INCLUDE_CDS
  if (UseSharedSpaces) {
    higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
                          (address)(metaspace_base + compressed_class_space_size()));
    lower_base = MIN2(metaspace_base, cds_base);
  } else
#endif
  {
    higher_address = metaspace_base + compressed_class_space_size();
    lower_base = metaspace_base;

    uint64_t klass_encoding_max = UnscaledClassSpaceMax << LogKlassAlignmentInBytes;
    // If compressed class space fits in lower 32G, we don't need a base.
    if (higher_address <= (address)klass_encoding_max) {
      lower_base = 0; // Effectively lower base is zero.
    }
  }

  Universe::set_narrow_klass_base(lower_base);

  // CDS uses LogKlassAlignmentInBytes for narrow_klass_shift. See
  // MetaspaceShared::initialize_dumptime_shared_and_meta_spaces() for
  // how dump time narrow_klass_shift is set. Although, CDS can work
  // with zero-shift mode also, to be consistent with AOT it uses
  // LogKlassAlignmentInBytes for klass shift so archived java heap objects
  // can be used at same time as AOT code.
  if (!UseSharedSpaces
      && (uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax) {
    Universe::set_narrow_klass_shift(0);
  } else {
    Universe::set_narrow_klass_shift(LogKlassAlignmentInBytes);
  }
  AOTLoader::set_narrow_klass_shift();
}

#if INCLUDE_CDS
// Return TRUE if the specified metaspace_base and cds_base are close enough
// to work with compressed klass pointers.
bool Metaspace::can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base) {
  assert(cds_base != 0 && UseSharedSpaces, "Only use with CDS");
  assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
  address lower_base = MIN2((address)metaspace_base, cds_base);
  address higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
                                (address)(metaspace_base + compressed_class_space_size()));
  return ((uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax);
}
#endif

// Try to allocate the metaspace at the requested addr.
void Metaspace::allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base) {
  assert(!DumpSharedSpaces, "compress klass space is allocated by MetaspaceShared class.");
  assert(using_class_space(), "called improperly");
  assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
  assert(compressed_class_space_size() < KlassEncodingMetaspaceMax,
         "Metaspace size is too big");
  assert_is_aligned(requested_addr, _reserve_alignment);
  assert_is_aligned(cds_base, _reserve_alignment);
  assert_is_aligned(compressed_class_space_size(), _reserve_alignment);

  // Don't use large pages for the class space.
  bool large_pages = false;

#if !(defined(AARCH64) || defined(PPC64))
  ReservedSpace metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                             _reserve_alignment,
                                             large_pages,
                                             requested_addr);
#else // AARCH64 || PPC64

  ReservedSpace metaspace_rs;

  // Our compressed klass pointers may fit nicely into the lower 32
  // bits.
  if ((uint64_t)requested_addr + compressed_class_space_size() < 4*G) {
    metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                 _reserve_alignment,
                                 large_pages,
                                 requested_addr);
  }

  if (! metaspace_rs.is_reserved()) {
    // Aarch64: Try to align metaspace so that we can decode a compressed
    // klass with a single MOVK instruction.  We can do this iff the
    // compressed class base is a multiple of 4G.
    // Aix: Search for a place where we can find memory. If we need to load
    // the base, 4G alignment is helpful, too.
    // PPC64: smaller heaps up to 2g will be mapped just below 4g. Then the
    // attempt to place the compressed class space just after the heap fails on
    // Linux 4.1.42 and higher because the launcher is loaded at 4g
    // (ELF_ET_DYN_BASE). In that case we reach here and search the address space
    // below 32g to get a zerobased CCS. For simplicity we reuse the search
    // strategy for AARCH64.

    size_t increment = AARCH64_ONLY(4*)G;
    for (char *a = align_up(requested_addr, increment);
         a < (char*)(1024*G);
         a += increment) {
      if (a == (char *)(32*G)) {
        // Go faster from here on. Zero-based is no longer possible.
        increment = 4*G;
      }

#if INCLUDE_CDS
      if (UseSharedSpaces
          && ! can_use_cds_with_metaspace_addr(a, cds_base)) {
        // We failed to find an aligned base that will reach.  Fall
        // back to using our requested addr.
        metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                     _reserve_alignment,
                                     large_pages,
                                     requested_addr);
        break;
      }
#endif

      metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                   _reserve_alignment,
                                   large_pages,
                                   a);
      if (metaspace_rs.is_reserved())
        break;
    }
  }

#endif // AARCH64 || PPC64

  if (!metaspace_rs.is_reserved()) {
#if INCLUDE_CDS
    if (UseSharedSpaces) {
      size_t increment = align_up(1*G, _reserve_alignment);

      // Keep trying to allocate the metaspace, increasing the requested_addr
      // by 1GB each time, until we reach an address that will no longer allow
      // use of CDS with compressed klass pointers.
      char *addr = requested_addr;
      while (!metaspace_rs.is_reserved() && (addr + increment > addr) &&
             can_use_cds_with_metaspace_addr(addr + increment, cds_base)) {
        addr = addr + increment;
        metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                     _reserve_alignment, large_pages, addr);
      }
    }
#endif
    // If no successful allocation then try to allocate the space anywhere.  If
    // that fails then OOM doom.  At this point we cannot try allocating the
    // metaspace as if UseCompressedClassPointers is off because too much
    // initialization has happened that depends on UseCompressedClassPointers.
    // So, UseCompressedClassPointers cannot be turned off at this point.
    if (!metaspace_rs.is_reserved()) {
      metaspace_rs = ReservedSpace(compressed_class_space_size(),
                                   _reserve_alignment, large_pages);
      if (!metaspace_rs.is_reserved()) {
        vm_exit_during_initialization(err_msg("Could not allocate metaspace: " SIZE_FORMAT " bytes",
                                              compressed_class_space_size()));
      }
    }
  }

  // If we got here then the metaspace got allocated.
  MemTracker::record_virtual_memory_type((address)metaspace_rs.base(), mtClass);

#if INCLUDE_CDS
  // Verify that we can use shared spaces.  Otherwise, turn off CDS.
  if (UseSharedSpaces && !can_use_cds_with_metaspace_addr(metaspace_rs.base(), cds_base)) {
    FileMapInfo::stop_sharing_and_unmap(
        "Could not allocate metaspace at a compatible address");
  }
#endif
  set_narrow_klass_base_and_shift((address)metaspace_rs.base(),
                                  UseSharedSpaces ? (address)cds_base : 0);

  initialize_class_space(metaspace_rs);

  LogTarget(Trace, gc, metaspace) lt;
  if (lt.is_enabled()) {
    ResourceMark rm;
    LogStream ls(lt);
    print_compressed_class_space(&ls, requested_addr);
  }
}

void Metaspace::print_compressed_class_space(outputStream* st, const char* requested_addr) {
  st->print_cr("Narrow klass base: " PTR_FORMAT ", Narrow klass shift: %d",
               p2i(Universe::narrow_klass_base()), Universe::narrow_klass_shift());
  if (_class_space_list != NULL) {
    address base = (address)_class_space_list->current_virtual_space()->bottom();
    st->print("Compressed class space size: " SIZE_FORMAT " Address: " PTR_FORMAT,
                 compressed_class_space_size(), p2i(base));
    if (requested_addr != 0) {
      st->print(" Req Addr: " PTR_FORMAT, p2i(requested_addr));
    }
    st->cr();
  }
}

// For UseCompressedClassPointers the class space is reserved above the top of
// the Java heap.  The argument passed in is at the base of the compressed space.
void Metaspace::initialize_class_space(ReservedSpace rs) {
  // The reserved space size may be bigger because of alignment, esp with UseLargePages
  assert(rs.size() >= CompressedClassSpaceSize,
         SIZE_FORMAT " != " SIZE_FORMAT, rs.size(), CompressedClassSpaceSize);
  assert(using_class_space(), "Must be using class space");
  _class_space_list = new VirtualSpaceList(rs);
  _chunk_manager_class = new ChunkManager(true/*is_class*/);

  if (!_class_space_list->initialization_succeeded()) {
    vm_exit_during_initialization("Failed to setup compressed class space virtual space list.");
  }
}

#endif

void Metaspace::ergo_initialize() {
  if (DumpSharedSpaces) {
    // Using large pages when dumping the shared archive is currently not implemented.
    FLAG_SET_ERGO(bool, UseLargePagesInMetaspace, false);
  }

  size_t page_size = os::vm_page_size();
  if (UseLargePages && UseLargePagesInMetaspace) {
    page_size = os::large_page_size();
  }

  _commit_alignment  = page_size;
  _reserve_alignment = MAX2(page_size, (size_t)os::vm_allocation_granularity());

  // Do not use FLAG_SET_ERGO to update MaxMetaspaceSize, since this will
  // override if MaxMetaspaceSize was set on the command line or not.
  // This information is needed later to conform to the specification of the
  // java.lang.management.MemoryUsage API.
  //
  // Ideally, we would be able to set the default value of MaxMetaspaceSize in
  // globals.hpp to the aligned value, but this is not possible, since the
  // alignment depends on other flags being parsed.
  MaxMetaspaceSize = align_down_bounded(MaxMetaspaceSize, _reserve_alignment);

  if (MetaspaceSize > MaxMetaspaceSize) {
    MetaspaceSize = MaxMetaspaceSize;
  }

  MetaspaceSize = align_down_bounded(MetaspaceSize, _commit_alignment);

  assert(MetaspaceSize <= MaxMetaspaceSize, "MetaspaceSize should be limited by MaxMetaspaceSize");

  MinMetaspaceExpansion = align_down_bounded(MinMetaspaceExpansion, _commit_alignment);
  MaxMetaspaceExpansion = align_down_bounded(MaxMetaspaceExpansion, _commit_alignment);

  CompressedClassSpaceSize = align_down_bounded(CompressedClassSpaceSize, _reserve_alignment);

  // Initial virtual space size will be calculated at global_initialize()
  size_t min_metaspace_sz =
      VIRTUALSPACEMULTIPLIER * InitialBootClassLoaderMetaspaceSize;
  if (UseCompressedClassPointers) {
    if ((min_metaspace_sz + CompressedClassSpaceSize) >  MaxMetaspaceSize) {
      if (min_metaspace_sz >= MaxMetaspaceSize) {
        vm_exit_during_initialization("MaxMetaspaceSize is too small.");
      } else {
        FLAG_SET_ERGO(size_t, CompressedClassSpaceSize,
                      MaxMetaspaceSize - min_metaspace_sz);
      }
    }
  } else if (min_metaspace_sz >= MaxMetaspaceSize) {
    FLAG_SET_ERGO(size_t, InitialBootClassLoaderMetaspaceSize,
                  min_metaspace_sz);
  }

  set_compressed_class_space_size(CompressedClassSpaceSize);
}

void Metaspace::global_initialize() {
  MetaspaceGC::initialize();

#if INCLUDE_CDS
  if (DumpSharedSpaces) {
    MetaspaceShared::initialize_dumptime_shared_and_meta_spaces();
  } else if (UseSharedSpaces) {
    // If any of the archived space fails to map, UseSharedSpaces
    // is reset to false. Fall through to the
    // (!DumpSharedSpaces && !UseSharedSpaces) case to set up class
    // metaspace.
    MetaspaceShared::initialize_runtime_shared_and_meta_spaces();
  }

  if (!DumpSharedSpaces && !UseSharedSpaces)
#endif // INCLUDE_CDS
  {
#ifdef _LP64
    if (using_class_space()) {
      char* base = (char*)align_up(Universe::heap()->reserved_region().end(), _reserve_alignment);
      allocate_metaspace_compressed_klass_ptrs(base, 0);
    }
#endif // _LP64
  }

  // Initialize these before initializing the VirtualSpaceList
  _first_chunk_word_size = InitialBootClassLoaderMetaspaceSize / BytesPerWord;
  _first_chunk_word_size = align_word_size_up(_first_chunk_word_size);
  // Make the first class chunk bigger than a medium chunk so it's not put
  // on the medium chunk list.   The next chunk will be small and progress
  // from there.  This size calculated by -version.
  _first_class_chunk_word_size = MIN2((size_t)MediumChunk*6,
                                     (CompressedClassSpaceSize/BytesPerWord)*2);
  _first_class_chunk_word_size = align_word_size_up(_first_class_chunk_word_size);
  // Arbitrarily set the initial virtual space to a multiple
  // of the boot class loader size.
  size_t word_size = VIRTUALSPACEMULTIPLIER * _first_chunk_word_size;
  word_size = align_up(word_size, Metaspace::reserve_alignment_words());

  // Initialize the list of virtual spaces.
  _space_list = new VirtualSpaceList(word_size);
  _chunk_manager_metadata = new ChunkManager(false/*metaspace*/);

  if (!_space_list->initialization_succeeded()) {
    vm_exit_during_initialization("Unable to setup metadata virtual space list.", NULL);
  }

  _tracer = new MetaspaceTracer();

  _initialized = true;

}

void Metaspace::post_initialize() {
  MetaspaceGC::post_initialize();
}

void Metaspace::verify_global_initialization() {
  assert(space_list() != NULL, "Metadata VirtualSpaceList has not been initialized");
  assert(chunk_manager_metadata() != NULL, "Metadata ChunkManager has not been initialized");

  if (using_class_space()) {
    assert(class_space_list() != NULL, "Class VirtualSpaceList has not been initialized");
    assert(chunk_manager_class() != NULL, "Class ChunkManager has not been initialized");
  }
}

size_t Metaspace::align_word_size_up(size_t word_size) {
  size_t byte_size = word_size * wordSize;
  return ReservedSpace::allocation_align_size_up(byte_size) / wordSize;
}

MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size,
                              MetaspaceObj::Type type, TRAPS) {
  assert(!_frozen, "sanity");
  assert(!(DumpSharedSpaces && THREAD->is_VM_thread()), "sanity");

  if (HAS_PENDING_EXCEPTION) {
    assert(false, "Should not allocate with exception pending");
    return NULL;  // caller does a CHECK_NULL too
  }

  assert(loader_data != NULL, "Should never pass around a NULL loader_data. "
        "ClassLoaderData::the_null_class_loader_data() should have been used.");

  MetadataType mdtype = (type == MetaspaceObj::ClassType) ? ClassType : NonClassType;

  // Try to allocate metadata.
  MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);

  if (result == NULL) {
    tracer()->report_metaspace_allocation_failure(loader_data, word_size, type, mdtype);

    // Allocation failed.
    if (is_init_completed()) {
      // Only start a GC if the bootstrapping has completed.
      // Try to clean out some heap memory and retry. This can prevent premature
      // expansion of the metaspace.
      result = Universe::heap()->satisfy_failed_metadata_allocation(loader_data, word_size, mdtype);
    }
  }

  if (result == NULL) {
    if (DumpSharedSpaces) {
      // CDS dumping keeps loading classes, so if we hit an OOM we probably will keep hitting OOM.
      // We should abort to avoid generating a potentially bad archive.
      tty->print_cr("Failed allocating metaspace object type %s of size " SIZE_FORMAT ". CDS dump aborted.",
          MetaspaceObj::type_name(type), word_size * BytesPerWord);
      tty->print_cr("Please increase MaxMetaspaceSize (currently " SIZE_FORMAT " bytes).", MaxMetaspaceSize);
      vm_exit(1);
    }
    report_metadata_oome(loader_data, word_size, type, mdtype, THREAD);
    assert(HAS_PENDING_EXCEPTION, "sanity");
    return NULL;
  }

  // Zero initialize.
  Copy::fill_to_words((HeapWord*)result, word_size, 0);

  return result;
}

void Metaspace::report_metadata_oome(ClassLoaderData* loader_data, size_t word_size, MetaspaceObj::Type type, MetadataType mdtype, TRAPS) {
  tracer()->report_metadata_oom(loader_data, word_size, type, mdtype);

  // If result is still null, we are out of memory.
  Log(gc, metaspace, freelist, oom) log;
  if (log.is_info()) {
    log.info("Metaspace (%s) allocation failed for size " SIZE_FORMAT,
             is_class_space_allocation(mdtype) ? "class" : "data", word_size);
    ResourceMark rm;
    if (log.is_debug()) {
      if (loader_data->metaspace_or_null() != NULL) {
        LogStream ls(log.debug());
        loader_data->print_value_on(&ls);
      }
    }
    LogStream ls(log.info());
    // In case of an OOM, log out a short but still useful report.
    MetaspaceUtils::print_basic_report(&ls, 0);
  }

  bool out_of_compressed_class_space = false;
  if (is_class_space_allocation(mdtype)) {
    ClassLoaderMetaspace* metaspace = loader_data->metaspace_non_null();
    out_of_compressed_class_space =
      MetaspaceUtils::committed_bytes(Metaspace::ClassType) +
      (metaspace->class_chunk_size(word_size) * BytesPerWord) >
      CompressedClassSpaceSize;
  }

  // -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
  const char* space_string = out_of_compressed_class_space ?
    "Compressed class space" : "Metaspace";

  report_java_out_of_memory(space_string);

  if (JvmtiExport::should_post_resource_exhausted()) {
    JvmtiExport::post_resource_exhausted(
        JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR,
        space_string);
  }

  if (!is_init_completed()) {
    vm_exit_during_initialization("OutOfMemoryError", space_string);
  }

  if (out_of_compressed_class_space) {
    THROW_OOP(Universe::out_of_memory_error_class_metaspace());
  } else {
    THROW_OOP(Universe::out_of_memory_error_metaspace());
  }
}

const char* Metaspace::metadata_type_name(Metaspace::MetadataType mdtype) {
  switch (mdtype) {
    case Metaspace::ClassType: return "Class";
    case Metaspace::NonClassType: return "Metadata";
    default:
      assert(false, "Got bad mdtype: %d", (int) mdtype);
      return NULL;
  }
}

void Metaspace::purge(MetadataType mdtype) {
  get_space_list(mdtype)->purge(get_chunk_manager(mdtype));
}

void Metaspace::purge() {
  MutexLockerEx cl(MetaspaceExpand_lock,
                   Mutex::_no_safepoint_check_flag);
  purge(NonClassType);
  if (using_class_space()) {
    purge(ClassType);
  }
}

bool Metaspace::contains(const void* ptr) {
  if (MetaspaceShared::is_in_shared_metaspace(ptr)) {
    return true;
  }
  return contains_non_shared(ptr);
}

bool Metaspace::contains_non_shared(const void* ptr) {
  if (using_class_space() && get_space_list(ClassType)->contains(ptr)) {
     return true;
  }

  return get_space_list(NonClassType)->contains(ptr);
}

// ClassLoaderMetaspace

ClassLoaderMetaspace::ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type)
  : _lock(lock)
  , _space_type(type)
  , _vsm(NULL)
  , _class_vsm(NULL)
{
  initialize(lock, type);
}

ClassLoaderMetaspace::~ClassLoaderMetaspace() {
  Metaspace::assert_not_frozen();
  DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_metaspace_deaths));
  delete _vsm;
  if (Metaspace::using_class_space()) {
    delete _class_vsm;
  }
}

void ClassLoaderMetaspace::initialize_first_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype) {
  Metachunk* chunk = get_initialization_chunk(type, mdtype);
  if (chunk != NULL) {
    // Add to this manager's list of chunks in use and make it the current_chunk().
    get_space_manager(mdtype)->add_chunk(chunk, true);
  }
}

Metachunk* ClassLoaderMetaspace::get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype) {
  size_t chunk_word_size = get_space_manager(mdtype)->get_initial_chunk_size(type);

  // Get a chunk from the chunk freelist
  Metachunk* chunk = Metaspace::get_chunk_manager(mdtype)->chunk_freelist_allocate(chunk_word_size);

  if (chunk == NULL) {
    chunk = Metaspace::get_space_list(mdtype)->get_new_chunk(chunk_word_size,
                                                  get_space_manager(mdtype)->medium_chunk_bunch());
  }

  return chunk;
}

void ClassLoaderMetaspace::initialize(Mutex* lock, Metaspace::MetaspaceType type) {
  Metaspace::verify_global_initialization();

  DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_metaspace_births));

  // Allocate SpaceManager for metadata objects.
  _vsm = new SpaceManager(Metaspace::NonClassType, type, lock);

  if (Metaspace::using_class_space()) {
    // Allocate SpaceManager for classes.
    _class_vsm = new SpaceManager(Metaspace::ClassType, type, lock);
  }

  MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);

  // Allocate chunk for metadata objects
  initialize_first_chunk(type, Metaspace::NonClassType);

  // Allocate chunk for class metadata objects
  if (Metaspace::using_class_space()) {
    initialize_first_chunk(type, Metaspace::ClassType);
  }
}

MetaWord* ClassLoaderMetaspace::allocate(size_t word_size, Metaspace::MetadataType mdtype) {
  Metaspace::assert_not_frozen();

  DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_allocs));

  // Don't use class_vsm() unless UseCompressedClassPointers is true.
  if (Metaspace::is_class_space_allocation(mdtype)) {
    return  class_vsm()->allocate(word_size);
  } else {
    return  vsm()->allocate(word_size);
  }
}

MetaWord* ClassLoaderMetaspace::expand_and_allocate(size_t word_size, Metaspace::MetadataType mdtype) {
  Metaspace::assert_not_frozen();
  size_t delta_bytes = MetaspaceGC::delta_capacity_until_GC(word_size * BytesPerWord);
  assert(delta_bytes > 0, "Must be");

  size_t before = 0;
  size_t after = 0;
  bool can_retry = true;
  MetaWord* res;
  bool incremented;

  // Each thread increments the HWM at most once. Even if the thread fails to increment
  // the HWM, an allocation is still attempted. This is because another thread must then
  // have incremented the HWM and therefore the allocation might still succeed.
  do {
    incremented = MetaspaceGC::inc_capacity_until_GC(delta_bytes, &after, &before, &can_retry);
    res = allocate(word_size, mdtype);
  } while (!incremented && res == NULL && can_retry);

  if (incremented) {
    Metaspace::tracer()->report_gc_threshold(before, after,
                                  MetaspaceGCThresholdUpdater::ExpandAndAllocate);
    log_trace(gc, metaspace)("Increase capacity to GC from " SIZE_FORMAT " to " SIZE_FORMAT, before, after);
  }

  return res;
}

size_t ClassLoaderMetaspace::allocated_blocks_bytes() const {
  return (vsm()->used_words() +
      (Metaspace::using_class_space() ? class_vsm()->used_words() : 0)) * BytesPerWord;
}

size_t ClassLoaderMetaspace::allocated_chunks_bytes() const {
  return (vsm()->capacity_words() +
      (Metaspace::using_class_space() ? class_vsm()->capacity_words() : 0)) * BytesPerWord;
}

void ClassLoaderMetaspace::deallocate(MetaWord* ptr, size_t word_size, bool is_class) {
  Metaspace::assert_not_frozen();
  assert(!SafepointSynchronize::is_at_safepoint()
         || Thread::current()->is_VM_thread(), "should be the VM thread");

  DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_external_deallocs));

  MutexLockerEx ml(vsm()->lock(), Mutex::_no_safepoint_check_flag);

  if (is_class && Metaspace::using_class_space()) {
    class_vsm()->deallocate(ptr, word_size);
  } else {
    vsm()->deallocate(ptr, word_size);
  }
}

size_t ClassLoaderMetaspace::class_chunk_size(size_t word_size) {
  assert(Metaspace::using_class_space(), "Has to use class space");
  return class_vsm()->calc_chunk_size(word_size);
}

void ClassLoaderMetaspace::print_on(outputStream* out) const {
  // Print both class virtual space counts and metaspace.
  if (Verbose) {
    vsm()->print_on(out);
    if (Metaspace::using_class_space()) {
      class_vsm()->print_on(out);
    }
  }
}

void ClassLoaderMetaspace::verify() {
  vsm()->verify();
  if (Metaspace::using_class_space()) {
    class_vsm()->verify();
  }
}

void ClassLoaderMetaspace::add_to_statistics_locked(ClassLoaderMetaspaceStatistics* out) const {
  assert_lock_strong(lock());
  vsm()->add_to_statistics_locked(&out->nonclass_sm_stats());
  if (Metaspace::using_class_space()) {
    class_vsm()->add_to_statistics_locked(&out->class_sm_stats());
  }
}

void ClassLoaderMetaspace::add_to_statistics(ClassLoaderMetaspaceStatistics* out) const {
  MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
  add_to_statistics_locked(out);
}

/////////////// Unit tests ///////////////

#ifndef PRODUCT

class TestVirtualSpaceNodeTest {
  static void chunk_up(size_t words_left, size_t& num_medium_chunks,
                                          size_t& num_small_chunks,
                                          size_t& num_specialized_chunks) {
    num_medium_chunks = words_left / MediumChunk;
    words_left = words_left % MediumChunk;

    num_small_chunks = words_left / SmallChunk;
    words_left = words_left % SmallChunk;
    // how many specialized chunks can we get?
    num_specialized_chunks = words_left / SpecializedChunk;
    assert(words_left % SpecializedChunk == 0, "should be nothing left");
  }

 public:
  static void test() {
    MutexLockerEx ml(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
    const size_t vsn_test_size_words = MediumChunk  * 4;
    const size_t vsn_test_size_bytes = vsn_test_size_words * BytesPerWord;

    // The chunk sizes must be multiples of eachother, or this will fail
    STATIC_ASSERT(MediumChunk % SmallChunk == 0);
    STATIC_ASSERT(SmallChunk % SpecializedChunk == 0);

    { // No committed memory in VSN
      ChunkManager cm(false);
      VirtualSpaceNode vsn(false, vsn_test_size_bytes);
      vsn.initialize();
      vsn.retire(&cm);
      assert(cm.sum_free_chunks_count() == 0, "did not commit any memory in the VSN");
    }

    { // All of VSN is committed, half is used by chunks
      ChunkManager cm(false);
      VirtualSpaceNode vsn(false, vsn_test_size_bytes);
      vsn.initialize();
      vsn.expand_by(vsn_test_size_words, vsn_test_size_words);
      vsn.get_chunk_vs(MediumChunk);
      vsn.get_chunk_vs(MediumChunk);
      vsn.retire(&cm);
      assert(cm.sum_free_chunks_count() == 2, "should have been memory left for 2 medium chunks");
      assert(cm.sum_free_chunks() == 2*MediumChunk, "sizes should add up");
    }

    const size_t page_chunks = 4 * (size_t)os::vm_page_size() / BytesPerWord;
    // This doesn't work for systems with vm_page_size >= 16K.
    if (page_chunks < MediumChunk) {
      // 4 pages of VSN is committed, some is used by chunks
      ChunkManager cm(false);
      VirtualSpaceNode vsn(false, vsn_test_size_bytes);

      vsn.initialize();
      vsn.expand_by(page_chunks, page_chunks);
      vsn.get_chunk_vs(SmallChunk);
      vsn.get_chunk_vs(SpecializedChunk);
      vsn.retire(&cm);

      // committed - used = words left to retire
      const size_t words_left = page_chunks - SmallChunk - SpecializedChunk;

      size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
      chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);

      assert(num_medium_chunks == 0, "should not get any medium chunks");
      assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
      assert(cm.sum_free_chunks() == words_left, "sizes should add up");
    }

    { // Half of VSN is committed, a humongous chunk is used
      ChunkManager cm(false);
      VirtualSpaceNode vsn(false, vsn_test_size_bytes);
      vsn.initialize();
      vsn.expand_by(MediumChunk * 2, MediumChunk * 2);
      vsn.get_chunk_vs(MediumChunk + SpecializedChunk); // Humongous chunks will be aligned up to MediumChunk + SpecializedChunk
      vsn.retire(&cm);

      const size_t words_left = MediumChunk * 2 - (MediumChunk + SpecializedChunk);
      size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
      chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);

      assert(num_medium_chunks == 0, "should not get any medium chunks");
      assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
      assert(cm.sum_free_chunks() == words_left, "sizes should add up");
    }

  }

#define assert_is_available_positive(word_size) \
  assert(vsn.is_available(word_size), \
         #word_size ": " PTR_FORMAT " bytes were not available in " \
         "VirtualSpaceNode [" PTR_FORMAT ", " PTR_FORMAT ")", \
         (uintptr_t)(word_size * BytesPerWord), p2i(vsn.bottom()), p2i(vsn.end()));

#define assert_is_available_negative(word_size) \
  assert(!vsn.is_available(word_size), \
         #word_size ": " PTR_FORMAT " bytes should not be available in " \
         "VirtualSpaceNode [" PTR_FORMAT ", " PTR_FORMAT ")", \
         (uintptr_t)(word_size * BytesPerWord), p2i(vsn.bottom()), p2i(vsn.end()));

  static void test_is_available_positive() {
    // Reserve some memory.
    VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
    assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");

    // Commit some memory.
    size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
    bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
    assert(expanded, "Failed to commit");

    // Check that is_available accepts the committed size.
    assert_is_available_positive(commit_word_size);

    // Check that is_available accepts half the committed size.
    size_t expand_word_size = commit_word_size / 2;
    assert_is_available_positive(expand_word_size);
  }

  static void test_is_available_negative() {
    // Reserve some memory.
    VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
    assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");

    // Commit some memory.
    size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
    bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
    assert(expanded, "Failed to commit");

    // Check that is_available doesn't accept a too large size.
    size_t two_times_commit_word_size = commit_word_size * 2;
    assert_is_available_negative(two_times_commit_word_size);
  }

  static void test_is_available_overflow() {
    // Reserve some memory.
    VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
    assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");

    // Commit some memory.
    size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
    bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
    assert(expanded, "Failed to commit");

    // Calculate a size that will overflow the virtual space size.
    void* virtual_space_max = (void*)(uintptr_t)-1;
    size_t bottom_to_max = pointer_delta(virtual_space_max, vsn.bottom(), 1);
    size_t overflow_size = bottom_to_max + BytesPerWord;
    size_t overflow_word_size = overflow_size / BytesPerWord;

    // Check that is_available can handle the overflow.
    assert_is_available_negative(overflow_word_size);
  }

  static void test_is_available() {
    TestVirtualSpaceNodeTest::test_is_available_positive();
    TestVirtualSpaceNodeTest::test_is_available_negative();
    TestVirtualSpaceNodeTest::test_is_available_overflow();
  }
};

#endif // !PRODUCT

struct chunkmanager_statistics_t {
  int num_specialized_chunks;
  int num_small_chunks;
  int num_medium_chunks;
  int num_humongous_chunks;
};

extern void test_metaspace_retrieve_chunkmanager_statistics(Metaspace::MetadataType mdType, chunkmanager_statistics_t* out) {
  ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(mdType);
  ChunkManagerStatistics stat;
  chunk_manager->collect_statistics(&stat);
  out->num_specialized_chunks = (int)stat.chunk_stats(SpecializedIndex).num();
  out->num_small_chunks = (int)stat.chunk_stats(SmallIndex).num();
  out->num_medium_chunks = (int)stat.chunk_stats(MediumIndex).num();
  out->num_humongous_chunks = (int)stat.chunk_stats(HumongousIndex).num();
}

struct chunk_geometry_t {
  size_t specialized_chunk_word_size;
  size_t small_chunk_word_size;
  size_t medium_chunk_word_size;
};

extern void test_metaspace_retrieve_chunk_geometry(Metaspace::MetadataType mdType, chunk_geometry_t* out) {
  if (mdType == Metaspace::NonClassType) {
    out->specialized_chunk_word_size = SpecializedChunk;
    out->small_chunk_word_size = SmallChunk;
    out->medium_chunk_word_size = MediumChunk;
  } else {
    out->specialized_chunk_word_size = ClassSpecializedChunk;
    out->small_chunk_word_size = ClassSmallChunk;
    out->medium_chunk_word_size = ClassMediumChunk;
  }
}