* Copyright (c) 2018, 2019 SAP SE. All rights reserved.

#include "memory/metaspace/counter.hpp"

#include "memory/metaspace/commitLimiter.hpp"

#include "memory/metaspace/counter.hpp"

static int next_node_id = 0;

// Create a new, empty, expandable list.

VirtualSpaceList::VirtualSpaceList(const char* name, CommitLimiter* commit_limiter)

  : _name(name),

    _first_node(NULL),

    _can_expand(true),

    _can_purge(true),

    _commit_limiter(commit_limiter),

    _reserved_words_counter(),

    _committed_words_counter()

{

// Create a new list. The list will contain one node only, which uses the given ReservedSpace.

// It will be not expandable beyond that first node.

VirtualSpaceList::VirtualSpaceList(const char* name, ReservedSpace rs, CommitLimiter* commit_limiter)

: _name(name),

  _first_node(NULL),

  _can_expand(false),

  _can_purge(false),

  _commit_limiter(commit_limiter),

  _reserved_words_counter(),

  _committed_words_counter()

{

  // Create the first node spanning the existing ReservedSpace. This will be the only node created

  // for this list since we cannot expand.

  VirtualSpaceNode* vsn = VirtualSpaceNode::create_node(next_node_id++,

                                                        rs, _commit_limiter,

                                                        &_reserved_words_counter, &_committed_words_counter);

  assert(vsn != NULL, "node creation failed");

  _first_node = vsn;

  _first_node->set_next(NULL);

  _nodes_counter.increment();

VirtualSpaceList::~VirtualSpaceList() {

  // Note: normally, there is no reason ever to delete a vslist since they are

  // global objects, but for gtests it makes sense to allow this.

  VirtualSpaceNode* vsn = _first_node;

  VirtualSpaceNode* vsn2 = vsn;

  while (vsn != NULL) {

    vsn2 = vsn->next();

    delete vsn;

    vsn = vsn2;

// Create a new node and append it to the list. After

// this function, _current_node shall point to a new empty node.

// List must be expandable for this to work.

void VirtualSpaceList::create_new_node() {

  assert(_can_expand, "List is not expandable");

  VirtualSpaceNode* vsn = VirtualSpaceNode::create_node(next_node_id ++,

                                                        Settings::virtual_space_node_default_word_size(),

                                                        _commit_limiter,

                                                        &_reserved_words_counter, &_committed_words_counter);

  assert(vsn != NULL, "node creation failed");

  vsn->set_next(_first_node);

  _first_node = vsn;

  _nodes_counter.increment();

}

// Allocate a root chunk from this list.

// Note: this just returns a chunk whose memory is reserved; no memory is committed yet.

// Hence, before using this chunk, it must be committed.

// Also, no limits are checked, since no committing takes place.

Metachunk*  VirtualSpaceList::allocate_root_chunk() {

  assert_lock_strong(MetaspaceExpand_lock);

  log_debug(metaspace)("VirtualSpaceList %s: allocate root chunk.", _name);

  if (_first_node == NULL ||

      _first_node->free_words() == 0) {

    // The current node is fully used up.

    log_debug(metaspace)("VirtualSpaceList %s: need new node.", _name);

    // Since all allocations from a VirtualSpaceNode happen in

    // root-chunk-size units, and the node size must be root-chunk-size aligned,

    // we should never have left-over space.

    assert(_first_node == NULL ||

           _first_node->free_words() == 0, "Sanity");

    if (_can_expand) {

      create_new_node();

    } else {

      return NULL; // We cannot expand this list.

    }

  Metachunk* c = _first_node->allocate_root_chunk();

  assert(c != NULL, "This should have worked");

  return c;

// Attempts to purge nodes. This will remove and delete nodes which only contain free chunks.

// The free chunks are removed from the freelists before the nodes are deleted.

// Return number of purged nodes.

int VirtualSpaceList::purge(MetachunkListCluster* freelists) {

  // Note: I am not sure all that purging business is even necessary anymore

  // since we have a good reclaim mechanism in place. Need to measure.

  assert_lock_strong(MetaspaceExpand_lock);

  if (_can_purge == false) {

    log_debug(metaspace)("VirtualSpaceList %s: cannot purge this list.", _name);

    return 0;

  }

  log_debug(metaspace)("VirtualSpaceList %s: purging...", _name);

  VirtualSpaceNode* vsn = _first_node;

  VirtualSpaceNode* prev_vsn = NULL;

  int num = 0, num_purged = 0;

  while (vsn != NULL) {

    VirtualSpaceNode* next_vsn = vsn->next();

    bool purged = vsn->attempt_purge(freelists);

    if (purged) {

      // Note: from now on do not dereference vsn!

      log_debug(metaspace)("VirtualSpaceList %s: purged node @" PTR_FORMAT, _name, p2i(vsn));

      if (_first_node == vsn) {

        _first_node = next_vsn;

      }

      DEBUG_ONLY(vsn = (VirtualSpaceNode*)0xdeadbeef;)

      if (prev_vsn != NULL) {

        prev_vsn->set_next(next_vsn);

      }

      num_purged ++;

      _nodes_counter.decrement();

    } else {

      prev_vsn = vsn;

    }

    vsn = next_vsn;

    num ++;

  log_debug(metaspace)("VirtualSpaceList %s: purged %d/%d nodes.", _name, num_purged, num);

  return num_purged;

}

// Print all nodes in this space list.

void VirtualSpaceList::print_on(outputStream* st) const {

  MutexLocker fcl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);

  st->print_cr("vsl %s:", _name);

  const VirtualSpaceNode* vsn = _first_node;

  int n = 0;

  while (vsn != NULL) {

    st->print("- node #%d: ", n);

    vsn->print_on(st);

    vsn = vsn->next();

    n ++;

  }

  st->print_cr("- total %d nodes, " SIZE_FORMAT " reserved words, " SIZE_FORMAT " committed words.",

               n, reserved_words(), committed_words());

}

void VirtualSpaceList::verify_locked(bool slow) const {

  assert_lock_strong(MetaspaceExpand_lock);

  assert(_name != NULL, "Sanity");

  int n = 0;

  if (_first_node != NULL) {

    size_t total_reserved_words = 0;

    size_t total_committed_words = 0;

    const VirtualSpaceNode* vsn = _first_node;

    while (vsn != NULL) {

      n ++;

      vsn->verify(slow);

      total_reserved_words += vsn->word_size();

      total_committed_words += vsn->committed_words();

      vsn = vsn->next();

    }

    _nodes_counter.check(n);

    _reserved_words_counter.check(total_reserved_words);

    _committed_words_counter.check(total_committed_words);

  } else {

    _reserved_words_counter.check(0);

    _committed_words_counter.check(0);

void VirtualSpaceList::verify(bool slow) const {

  MutexLocker fcl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);

  verify_locked(slow);

#endif

// Returns true if this pointer is contained in one of our nodes.

bool VirtualSpaceList::contains(const MetaWord* p) const {

  const VirtualSpaceNode* vsn = _first_node;

  while (vsn != NULL) {

    if (vsn->contains(p)) {

    vsn = vsn->next();

VirtualSpaceList* VirtualSpaceList::_vslist_class = NULL;

VirtualSpaceList* VirtualSpaceList::_vslist_nonclass = NULL;

void VirtualSpaceList::set_vslist_class(VirtualSpaceList* vsl) {

  assert(_vslist_class == NULL, "Sanity");

  _vslist_class = vsl;

void VirtualSpaceList::set_vslist_nonclass(VirtualSpaceList* vsl) {

  assert(_vslist_nonclass == NULL, "Sanity");

  _vslist_nonclass = vsl;