view src/share/vm/gc_implementation/g1/sparsePRT.cpp @ 2034:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
parents 72a161e62cc4
children 97ba643ea3ed
line wrap: on
line source
/*
 * Copyright (c) 2001, 2010, 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 "gc_implementation/g1/heapRegion.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "gc_implementation/g1/sparsePRT.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/cardTableModRefBS.hpp"
#include "memory/space.inline.hpp"
#include "runtime/mutexLocker.hpp"

#define SPARSE_PRT_VERBOSE 0

#define UNROLL_CARD_LOOPS  1

void SparsePRT::init_iterator(SparsePRTIter* sprt_iter) {
    sprt_iter->init(this);
}

void SparsePRTEntry::init(RegionIdx_t region_ind) {
  _region_ind = region_ind;
  _next_index = NullEntry;

#if UNROLL_CARD_LOOPS
  assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
  for (int i = 0; i < cards_num(); i += UnrollFactor) {
    _cards[i] = NullEntry;
    _cards[i + 1] = NullEntry;
    _cards[i + 2] = NullEntry;
    _cards[i + 3] = NullEntry;
  }
#else
  for (int i = 0; i < cards_num(); i++)
    _cards[i] = NullEntry;
#endif
}

bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
#if UNROLL_CARD_LOOPS
  assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
  for (int i = 0; i < cards_num(); i += UnrollFactor) {
    if (_cards[i] == card_index ||
        _cards[i + 1] == card_index ||
        _cards[i + 2] == card_index ||
        _cards[i + 3] == card_index) return true;
  }
#else
  for (int i = 0; i < cards_num(); i++) {
    if (_cards[i] == card_index) return true;
  }
#endif
  // Otherwise, we're full.
  return false;
}

int SparsePRTEntry::num_valid_cards() const {
  int sum = 0;
#if UNROLL_CARD_LOOPS
  assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
  for (int i = 0; i < cards_num(); i += UnrollFactor) {
    sum += (_cards[i] != NullEntry);
    sum += (_cards[i + 1] != NullEntry);
    sum += (_cards[i + 2] != NullEntry);
    sum += (_cards[i + 3] != NullEntry);
  }
#else
  for (int i = 0; i < cards_num(); i++) {
    sum += (_cards[i] != NullEntry);
  }
#endif
  // Otherwise, we're full.
  return sum;
}

SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
#if UNROLL_CARD_LOOPS
  assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
  CardIdx_t c;
  for (int i = 0; i < cards_num(); i += UnrollFactor) {
    c = _cards[i];
    if (c == card_index) return found;
    if (c == NullEntry) { _cards[i] = card_index; return added; }
    c = _cards[i + 1];
    if (c == card_index) return found;
    if (c == NullEntry) { _cards[i + 1] = card_index; return added; }
    c = _cards[i + 2];
    if (c == card_index) return found;
    if (c == NullEntry) { _cards[i + 2] = card_index; return added; }
    c = _cards[i + 3];
    if (c == card_index) return found;
    if (c == NullEntry) { _cards[i + 3] = card_index; return added; }
  }
#else
  for (int i = 0; i < cards_num(); i++) {
    CardIdx_t c = _cards[i];
    if (c == card_index) return found;
    if (c == NullEntry) { _cards[i] = card_index; return added; }
  }
#endif
  // Otherwise, we're full.
  return overflow;
}

void SparsePRTEntry::copy_cards(CardIdx_t* cards) const {
#if UNROLL_CARD_LOOPS
  assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
  for (int i = 0; i < cards_num(); i += UnrollFactor) {
    cards[i] = _cards[i];
    cards[i + 1] = _cards[i + 1];
    cards[i + 2] = _cards[i + 2];
    cards[i + 3] = _cards[i + 3];
  }
#else
  for (int i = 0; i < cards_num(); i++) {
    cards[i] = _cards[i];
  }
#endif
}

void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
  copy_cards(&e->_cards[0]);
}

// ----------------------------------------------------------------------

RSHashTable::RSHashTable(size_t capacity) :
  _capacity(capacity), _capacity_mask(capacity-1),
  _occupied_entries(0), _occupied_cards(0),
  _entries((SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, SparsePRTEntry::size() * capacity)),
  _buckets(NEW_C_HEAP_ARRAY(int, capacity)),
  _free_list(NullEntry), _free_region(0)
{
  clear();
}

RSHashTable::~RSHashTable() {
  if (_entries != NULL) {
    FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries);
    _entries = NULL;
  }
  if (_buckets != NULL) {
    FREE_C_HEAP_ARRAY(int, _buckets);
    _buckets = NULL;
  }
}

void RSHashTable::clear() {
  _occupied_entries = 0;
  _occupied_cards = 0;
  guarantee(_entries != NULL, "INV");
  guarantee(_buckets != NULL, "INV");

  guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
                "_capacity too large");

  // This will put -1 == NullEntry in the key field of all entries.
  memset(_entries, NullEntry, _capacity * SparsePRTEntry::size());
  memset(_buckets, NullEntry, _capacity * sizeof(int));
  _free_list = NullEntry;
  _free_region = 0;
}

bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
  SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
  assert(e != NULL && e->r_ind() == region_ind,
         "Postcondition of call above.");
  SparsePRTEntry::AddCardResult res = e->add_card(card_index);
  if (res == SparsePRTEntry::added) _occupied_cards++;
#if SPARSE_PRT_VERBOSE
  gclog_or_tty->print_cr("       after add_card[%d]: valid-cards = %d.",
                         pointer_delta(e, _entries, SparsePRTEntry::size()),
                         e->num_valid_cards());
#endif
  assert(e->num_valid_cards() > 0, "Postcondition");
  return res != SparsePRTEntry::overflow;
}

bool RSHashTable::get_cards(RegionIdx_t region_ind, CardIdx_t* cards) {
  int ind = (int) (region_ind & capacity_mask());
  int cur_ind = _buckets[ind];
  SparsePRTEntry* cur;
  while (cur_ind != NullEntry &&
         (cur = entry(cur_ind))->r_ind() != region_ind) {
    cur_ind = cur->next_index();
  }

  if (cur_ind == NullEntry) return false;
  // Otherwise...
  assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
  assert(cur->num_valid_cards() > 0, "Inv");
  cur->copy_cards(cards);
  return true;
}

SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) {
  int ind = (int) (region_ind & capacity_mask());
  int cur_ind = _buckets[ind];
  SparsePRTEntry* cur;
  while (cur_ind != NullEntry &&
         (cur = entry(cur_ind))->r_ind() != region_ind) {
    cur_ind = cur->next_index();
  }

  if (cur_ind == NullEntry) return NULL;
  // Otherwise...
  assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
  assert(cur->num_valid_cards() > 0, "Inv");
  return cur;
}

bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
  int ind = (int) (region_ind & capacity_mask());
  int* prev_loc = &_buckets[ind];
  int cur_ind = *prev_loc;
  SparsePRTEntry* cur;
  while (cur_ind != NullEntry &&
         (cur = entry(cur_ind))->r_ind() != region_ind) {
    prev_loc = cur->next_index_addr();
    cur_ind = *prev_loc;
  }

  if (cur_ind == NullEntry) return false;
  // Otherwise, splice out "cur".
  *prev_loc = cur->next_index();
  _occupied_cards -= cur->num_valid_cards();
  free_entry(cur_ind);
  _occupied_entries--;
  return true;
}

SparsePRTEntry*
RSHashTable::entry_for_region_ind(RegionIdx_t region_ind) const {
  assert(occupied_entries() < capacity(), "Precondition");
  int ind = (int) (region_ind & capacity_mask());
  int cur_ind = _buckets[ind];
  SparsePRTEntry* cur;
  while (cur_ind != NullEntry &&
         (cur = entry(cur_ind))->r_ind() != region_ind) {
    cur_ind = cur->next_index();
  }

  if (cur_ind != NullEntry) {
    assert(cur->r_ind() == region_ind, "Loop postcondition + test");
    return cur;
  } else {
    return NULL;
  }
}

SparsePRTEntry*
RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
  SparsePRTEntry* res = entry_for_region_ind(region_ind);
  if (res == NULL) {
    int new_ind = alloc_entry();
    assert(0 <= new_ind && (size_t)new_ind < capacity(), "There should be room.");
    res = entry(new_ind);
    res->init(region_ind);
    // Insert at front.
    int ind = (int) (region_ind & capacity_mask());
    res->set_next_index(_buckets[ind]);
    _buckets[ind] = new_ind;
    _occupied_entries++;
  }
  return res;
}

int RSHashTable::alloc_entry() {
  int res;
  if (_free_list != NullEntry) {
    res = _free_list;
    _free_list = entry(res)->next_index();
    return res;
  } else if ((size_t) _free_region+1 < capacity()) {
    res = _free_region;
    _free_region++;
    return res;
  } else {
    return NullEntry;
  }
}

void RSHashTable::free_entry(int fi) {
  entry(fi)->set_next_index(_free_list);
  _free_list = fi;
}

void RSHashTable::add_entry(SparsePRTEntry* e) {
  assert(e->num_valid_cards() > 0, "Precondition.");
  SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
  e->copy_cards(e2);
  _occupied_cards += e2->num_valid_cards();
  assert(e2->num_valid_cards() > 0, "Postcondition.");
}

CardIdx_t RSHashTableIter::find_first_card_in_list() {
  CardIdx_t res;
  while (_bl_ind != RSHashTable::NullEntry) {
    res = _rsht->entry(_bl_ind)->card(0);
    if (res != SparsePRTEntry::NullEntry) {
      return res;
    } else {
      _bl_ind = _rsht->entry(_bl_ind)->next_index();
    }
  }
  // Otherwise, none found:
  return SparsePRTEntry::NullEntry;
}

size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) {
  return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci;
}

bool RSHashTableIter::has_next(size_t& card_index) {
  _card_ind++;
  CardIdx_t ci;
  if (_card_ind < SparsePRTEntry::cards_num() &&
      ((ci = _rsht->entry(_bl_ind)->card(_card_ind)) !=
       SparsePRTEntry::NullEntry)) {
    card_index = compute_card_ind(ci);
    return true;
  }
  // Otherwise, must find the next valid entry.
  _card_ind = 0;

  if (_bl_ind != RSHashTable::NullEntry) {
      _bl_ind = _rsht->entry(_bl_ind)->next_index();
      ci = find_first_card_in_list();
      if (ci != SparsePRTEntry::NullEntry) {
        card_index = compute_card_ind(ci);
        return true;
      }
  }
  // If we didn't return above, must go to the next non-null table index.
  _tbl_ind++;
  while ((size_t)_tbl_ind < _rsht->capacity()) {
    _bl_ind = _rsht->_buckets[_tbl_ind];
    ci = find_first_card_in_list();
    if (ci != SparsePRTEntry::NullEntry) {
      card_index = compute_card_ind(ci);
      return true;
    }
    // Otherwise, try next entry.
    _tbl_ind++;
  }
  // Otherwise, there were no entry.
  return false;
}

bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
  SparsePRTEntry* e = entry_for_region_ind(region_index);
  return (e != NULL && e->contains_card(card_index));
}

size_t RSHashTable::mem_size() const {
  return sizeof(this) +
    capacity() * (SparsePRTEntry::size() + sizeof(int));
}

// ----------------------------------------------------------------------

SparsePRT* SparsePRT::_head_expanded_list = NULL;

void SparsePRT::add_to_expanded_list(SparsePRT* sprt) {
  // We could expand multiple times in a pause -- only put on list once.
  if (sprt->expanded()) return;
  sprt->set_expanded(true);
  SparsePRT* hd = _head_expanded_list;
  while (true) {
    sprt->_next_expanded = hd;
    SparsePRT* res =
      (SparsePRT*)
      Atomic::cmpxchg_ptr(sprt, &_head_expanded_list, hd);
    if (res == hd) return;
    else hd = res;
  }
}


SparsePRT* SparsePRT::get_from_expanded_list() {
  SparsePRT* hd = _head_expanded_list;
  while (hd != NULL) {
    SparsePRT* next = hd->next_expanded();
    SparsePRT* res =
      (SparsePRT*)
      Atomic::cmpxchg_ptr(next, &_head_expanded_list, hd);
    if (res == hd) {
      hd->set_next_expanded(NULL);
      return hd;
    } else {
      hd = res;
    }
  }
  return NULL;
}


void SparsePRT::cleanup_all() {
  // First clean up all expanded tables so they agree on next and cur.
  SparsePRT* sprt = get_from_expanded_list();
  while (sprt != NULL) {
    sprt->cleanup();
    sprt = get_from_expanded_list();
  }
}


SparsePRT::SparsePRT(HeapRegion* hr) :
  _hr(hr), _expanded(false), _next_expanded(NULL)
{
  _cur = new RSHashTable(InitialCapacity);
  _next = _cur;
}


SparsePRT::~SparsePRT() {
  assert(_next != NULL && _cur != NULL, "Inv");
  if (_cur != _next) { delete _cur; }
  delete _next;
}


size_t SparsePRT::mem_size() const {
  // We ignore "_cur" here, because it either = _next, or else it is
  // on the deleted list.
  return sizeof(this) + _next->mem_size();
}

bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
#if SPARSE_PRT_VERBOSE
  gclog_or_tty->print_cr("  Adding card %d from region %d to region %d sparse.",
                card_index, region_id, _hr->hrs_index());
#endif
  if (_next->occupied_entries() * 2 > _next->capacity()) {
    expand();
  }
  return _next->add_card(region_id, card_index);
}

bool SparsePRT::get_cards(RegionIdx_t region_id, CardIdx_t* cards) {
  return _next->get_cards(region_id, cards);
}

SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
  return _next->get_entry(region_id);
}

bool SparsePRT::delete_entry(RegionIdx_t region_id) {
  return _next->delete_entry(region_id);
}

void SparsePRT::clear() {
  // If they differ, _next is bigger then cur, so next has no chance of
  // being the initial size.
  if (_next != _cur) {
    delete _next;
  }

  if (_cur->capacity() != InitialCapacity) {
    delete _cur;
    _cur = new RSHashTable(InitialCapacity);
  } else {
    _cur->clear();
  }
  _next = _cur;
}

void SparsePRT::cleanup() {
  // Make sure that the current and next tables agree.
  if (_cur != _next) {
    delete _cur;
  }
  _cur = _next;
  set_expanded(false);
}

void SparsePRT::expand() {
  RSHashTable* last = _next;
  _next = new RSHashTable(last->capacity() * 2);

#if SPARSE_PRT_VERBOSE
  gclog_or_tty->print_cr("  Expanded sparse table for %d to %d.",
                _hr->hrs_index(), _next->capacity());
#endif
  for (size_t i = 0; i < last->capacity(); i++) {
    SparsePRTEntry* e = last->entry((int)i);
    if (e->valid_entry()) {
#if SPARSE_PRT_VERBOSE
      gclog_or_tty->print_cr("    During expansion, transferred entry for %d.",
                    e->r_ind());
#endif
      _next->add_entry(e);
    }
  }
  if (last != _cur) {
    delete last;
  }
  add_to_expanded_list(this);
}