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 /*

  * Copyright (c) 2001, 2013, 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 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, mtGC)),

   _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)),

   _free_list(NullEntry), _free_region(0)

 {

   clear();

 }

 RSHashTable::~RSHashTable() {

   if (_entries != NULL) {

     FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries, mtGC);

     _entries = NULL;

   }

   if (_buckets != NULL) {

     FREE_C_HEAP_ARRAY(int, _buckets, mtGC);

     _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(RSHashTable) +

     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::reset_for_cleanup_tasks() {

   _head_expanded_list = NULL;

 }

 void SparsePRT::do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task) {

   if (should_be_on_expanded_list()) {

     sprt_cleanup_task->add(this);

   }

 }

 void SparsePRT::finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task) {

   assert(ParGCRareEvent_lock->owned_by_self(), "pre-condition");

   SparsePRT* head = sprt_cleanup_task->head();

   SparsePRT* tail = sprt_cleanup_task->tail();

   if (head != NULL) {

     assert(tail != NULL, "if head is not NULL, so should tail");

     tail->set_next_expanded(_head_expanded_list);

     _head_expanded_list = head;

   } else {

     assert(tail == NULL, "if head is NULL, so should tail");

   }

 }

 bool SparsePRT::should_be_on_expanded_list() {

   if (_expanded) {

     assert(_cur != _next, "if _expanded is true, cur should be != _next");

   } else {

     assert(_cur == _next, "if _expanded is false, cur should be == _next");

   }

   return expanded();

 }

 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(SparsePRT) + _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 %u sparse.",

                          card_index, region_id, _hr->hrm_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;

   _expanded = false;

 }

 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 %u to %d.",

                          _hr->hrm_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);

 }

 void SparsePRTCleanupTask::add(SparsePRT* sprt) {

   assert(sprt->should_be_on_expanded_list(), "pre-condition");

   sprt->set_next_expanded(NULL);

   if (_tail != NULL) {

     _tail->set_next_expanded(sprt);

   } else {

     _head = sprt;

   }

   _tail = sprt;

 }