jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/sparsePRT.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/sparsePRT.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/sparsePRT.cpp

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7091: a8ea2f110d87
child 7535: 7ae4e26cb1e0
permissions: -rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

 /*
  * 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;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/sparsePRT.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/sparsePRT.cpp