jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp@2ace1c4ee8da (annotated)

src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp@2ace1c4ee8da (annotated)

src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp

Tue, 10 Jan 2012 18:58:13 -0500

author: tonyp
date: Tue, 10 Jan 2012 18:58:13 -0500
changeset 3416: 2ace1c4ee8da
parent 2453: 2250ee17e258
child 3900: d2a62e0f25eb
permissions: -rw-r--r--

6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso

 /*
  * Copyright (c) 2001, 2011, 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/g1BlockOffsetTable.inline.hpp"
 #include "memory/space.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/java.hpp"
 //////////////////////////////////////////////////////////////////////
 // G1BlockOffsetSharedArray
 //////////////////////////////////////////////////////////////////////
 G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion reserved,
                                                    size_t init_word_size) :
   _reserved(reserved), _end(NULL)
 {
   size_t size = compute_size(reserved.word_size());
   ReservedSpace rs(ReservedSpace::allocation_align_size_up(size));
   if (!rs.is_reserved()) {
     vm_exit_during_initialization("Could not reserve enough space for heap offset array");
   }
   if (!_vs.initialize(rs, 0)) {
     vm_exit_during_initialization("Could not reserve enough space for heap offset array");
   }
   _offset_array = (u_char*)_vs.low_boundary();
   resize(init_word_size);
   if (TraceBlockOffsetTable) {
     gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
     gclog_or_tty->print_cr("  "
                   "  rs.base(): " INTPTR_FORMAT
                   "  rs.size(): " INTPTR_FORMAT
                   "  rs end(): " INTPTR_FORMAT,
                   rs.base(), rs.size(), rs.base() + rs.size());
     gclog_or_tty->print_cr("  "
                   "  _vs.low_boundary(): " INTPTR_FORMAT
                   "  _vs.high_boundary(): " INTPTR_FORMAT,
                   _vs.low_boundary(),
                   _vs.high_boundary());
   }
 }
 void G1BlockOffsetSharedArray::resize(size_t new_word_size) {
   assert(new_word_size <= _reserved.word_size(), "Resize larger than reserved");
   size_t new_size = compute_size(new_word_size);
   size_t old_size = _vs.committed_size();
   size_t delta;
   char* high = _vs.high();
   _end = _reserved.start() + new_word_size;
   if (new_size > old_size) {
     delta = ReservedSpace::page_align_size_up(new_size - old_size);
     assert(delta > 0, "just checking");
     if (!_vs.expand_by(delta)) {
       // Do better than this for Merlin
       vm_exit_out_of_memory(delta, "offset table expansion");
     }
     assert(_vs.high() == high + delta, "invalid expansion");
     // Initialization of the contents is left to the
     // G1BlockOffsetArray that uses it.
   } else {
     delta = ReservedSpace::page_align_size_down(old_size - new_size);
     if (delta == 0) return;
     _vs.shrink_by(delta);
     assert(_vs.high() == high - delta, "invalid expansion");
   }
 }
 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
   assert(p >= _reserved.start(), "just checking");
   size_t delta = pointer_delta(p, _reserved.start());
   return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
 }
 //////////////////////////////////////////////////////////////////////
 // G1BlockOffsetArray
 //////////////////////////////////////////////////////////////////////
 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
                                        MemRegion mr, bool init_to_zero) :
   G1BlockOffsetTable(mr.start(), mr.end()),
   _unallocated_block(_bottom),
   _array(array), _csp(NULL),
   _init_to_zero(init_to_zero) {
   assert(_bottom <= _end, "arguments out of order");
   if (!_init_to_zero) {
     // initialize cards to point back to mr.start()
     set_remainder_to_point_to_start(mr.start() + N_words, mr.end());
     _array->set_offset_array(0, 0);  // set first card to 0
   }
 }
 void G1BlockOffsetArray::set_space(Space* sp) {
   _sp = sp;
   _csp = sp->toContiguousSpace();
 }
 // The arguments follow the normal convention of denoting
 // a right-open interval: [start, end)
 void
 G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
   if (start >= end) {
     // The start address is equal to the end address (or to
     // the right of the end address) so there are not cards
     // that need to be updated..
     return;
   }
   // Write the backskip value for each region.
   //
   //    offset
   //    card             2nd                       3rd
   //     | +- 1st        |                         |
   //     v v             v                         v
   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+     +-+-+-+-+-+-+-+-+-+-+-
   //    |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
   //    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+     +-+-+-+-+-+-+-+-+-+-+-
   //    11              19                        75
   //      12
   //
   //    offset card is the card that points to the start of an object
   //      x - offset value of offset card
   //    1st - start of first logarithmic region
   //      0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
   //    2nd - start of second logarithmic region
   //      1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
   //    3rd - start of third logarithmic region
   //      2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
   //
   //    integer below the block offset entry is an example of
   //    the index of the entry
   //
   //    Given an address,
   //      Find the index for the address
   //      Find the block offset table entry
   //      Convert the entry to a back slide
   //        (e.g., with today's, offset = 0x81 =>
   //          back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
   //      Move back N (e.g., 8) entries and repeat with the
   //        value of the new entry
   //
   size_t start_card = _array->index_for(start);
   size_t end_card = _array->index_for(end-1);
   assert(start ==_array->address_for_index(start_card), "Precondition");
   assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
   set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
 }
 // Unlike the normal convention in this code, the argument here denotes
 // a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
 // above.
 void
 G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
   if (start_card > end_card) {
     return;
   }
   assert(start_card > _array->index_for(_bottom), "Cannot be first card");
   assert(_array->offset_array(start_card-1) <= N_words,
          "Offset card has an unexpected value");
   size_t start_card_for_region = start_card;
   u_char offset = max_jubyte;
   for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
     // -1 so that the the card with the actual offset is counted.  Another -1
     // so that the reach ends in this region and not at the start
     // of the next.
     size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
     offset = N_words + i;
     if (reach >= end_card) {
       _array->set_offset_array(start_card_for_region, end_card, offset);
       start_card_for_region = reach + 1;
       break;
     }
     _array->set_offset_array(start_card_for_region, reach, offset);
     start_card_for_region = reach + 1;
   }
   assert(start_card_for_region > end_card, "Sanity check");
   DEBUG_ONLY(check_all_cards(start_card, end_card);)
 }
 // The block [blk_start, blk_end) has been allocated;
 // adjust the block offset table to represent this information;
 // right-open interval: [blk_start, blk_end)
 void
 G1BlockOffsetArray::alloc_block(HeapWord* blk_start, HeapWord* blk_end) {
   mark_block(blk_start, blk_end);
   allocated(blk_start, blk_end);
 }
 // Adjust BOT to show that a previously whole block has been split
 // into two.
 void G1BlockOffsetArray::split_block(HeapWord* blk, size_t blk_size,
                                      size_t left_blk_size) {
   // Verify that the BOT shows [blk, blk + blk_size) to be one block.
   verify_single_block(blk, blk_size);
   // Update the BOT to indicate that [blk + left_blk_size, blk + blk_size)
   // is one single block.
   mark_block(blk + left_blk_size, blk + blk_size);
 }
 // Action_mark - update the BOT for the block [blk_start, blk_end).
 //               Current typical use is for splitting a block.
 // Action_single - update the BOT for an allocation.
 // Action_verify - BOT verification.
 void G1BlockOffsetArray::do_block_internal(HeapWord* blk_start,
                                            HeapWord* blk_end,
                                            Action action) {
   assert(Universe::heap()->is_in_reserved(blk_start),
          "reference must be into the heap");
   assert(Universe::heap()->is_in_reserved(blk_end-1),
          "limit must be within the heap");
   // This is optimized to make the test fast, assuming we only rarely
   // cross boundaries.
   uintptr_t end_ui = (uintptr_t)(blk_end - 1);
   uintptr_t start_ui = (uintptr_t)blk_start;
   // Calculate the last card boundary preceding end of blk
   intptr_t boundary_before_end = (intptr_t)end_ui;
   clear_bits(boundary_before_end, right_n_bits(LogN));
   if (start_ui <= (uintptr_t)boundary_before_end) {
     // blk starts at or crosses a boundary
     // Calculate index of card on which blk begins
     size_t    start_index = _array->index_for(blk_start);
     // Index of card on which blk ends
     size_t    end_index   = _array->index_for(blk_end - 1);
     // Start address of card on which blk begins
     HeapWord* boundary    = _array->address_for_index(start_index);
     assert(boundary <= blk_start, "blk should start at or after boundary");
     if (blk_start != boundary) {
       // blk starts strictly after boundary
       // adjust card boundary and start_index forward to next card
       boundary += N_words;
       start_index++;
     }
     assert(start_index <= end_index, "monotonicity of index_for()");
     assert(boundary <= (HeapWord*)boundary_before_end, "tautology");
     switch (action) {
       case Action_mark: {
         if (init_to_zero()) {
           _array->set_offset_array(start_index, boundary, blk_start);
           break;
         } // Else fall through to the next case
       }
       case Action_single: {
         _array->set_offset_array(start_index, boundary, blk_start);
         // We have finished marking the "offset card". We need to now
         // mark the subsequent cards that this blk spans.
         if (start_index < end_index) {
           HeapWord* rem_st = _array->address_for_index(start_index) + N_words;
           HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
           set_remainder_to_point_to_start(rem_st, rem_end);
         }
         break;
       }
       case Action_check: {
         _array->check_offset_array(start_index, boundary, blk_start);
         // We have finished checking the "offset card". We need to now
         // check the subsequent cards that this blk spans.
         check_all_cards(start_index + 1, end_index);
         break;
       }
       default:
         ShouldNotReachHere();
     }
   }
 }
 // The card-interval [start_card, end_card] is a closed interval; this
 // is an expensive check -- use with care and only under protection of
 // suitable flag.
 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
   if (end_card < start_card) {
     return;
   }
   guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
   for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
     u_char entry = _array->offset_array(c);
     if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
       guarantee(entry > N_words, "Should be in logarithmic region");
     }
     size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
     size_t landing_card = c - backskip;
     guarantee(landing_card >= (start_card - 1), "Inv");
     if (landing_card >= start_card) {
       guarantee(_array->offset_array(landing_card) <= entry, "monotonicity");
     } else {
       guarantee(landing_card == start_card - 1, "Tautology");
       guarantee(_array->offset_array(landing_card) <= N_words, "Offset value");
     }
   }
 }
 // The range [blk_start, blk_end) represents a single contiguous block
 // of storage; modify the block offset table to represent this
 // information; Right-open interval: [blk_start, blk_end)
 // NOTE: this method does _not_ adjust _unallocated_block.
 void
 G1BlockOffsetArray::single_block(HeapWord* blk_start, HeapWord* blk_end) {
   do_block_internal(blk_start, blk_end, Action_single);
 }
 // Mark the BOT such that if [blk_start, blk_end) straddles a card
 // boundary, the card following the first such boundary is marked
 // with the appropriate offset.
 // NOTE: this method does _not_ adjust _unallocated_block or
 // any cards subsequent to the first one.
 void
 G1BlockOffsetArray::mark_block(HeapWord* blk_start, HeapWord* blk_end) {
   do_block_internal(blk_start, blk_end, Action_mark);
 }
 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   // Must read this exactly once because it can be modified by parallel
   // allocation.
   HeapWord* ub = _unallocated_block;
   if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
     assert(ub < _end, "tautology (see above)");
     return ub;
   }
   // Otherwise, find the block start using the table.
   HeapWord* q = block_at_or_preceding(addr, false, 0);
   return forward_to_block_containing_addr(q, addr);
 }
 // This duplicates a little code from the above: unavoidable.
 HeapWord*
 G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   // Must read this exactly once because it can be modified by parallel
   // allocation.
   HeapWord* ub = _unallocated_block;
   if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
     assert(ub < _end, "tautology (see above)");
     return ub;
   }
   // Otherwise, find the block start using the table.
   HeapWord* q = block_at_or_preceding(addr, false, 0);
   HeapWord* n = q + _sp->block_size(q);
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 HeapWord*
 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
                                                           HeapWord* n,
                                                           const void* addr) {
   // We're not in the normal case.  We need to handle an important subcase
   // here: LAB allocation.  An allocation previously recorded in the
   // offset table was actually a lab allocation, and was divided into
   // several objects subsequently.  Fix this situation as we answer the
   // query, by updating entries as we cross them.
   // If the fist object's end q is at the card boundary. Start refining
   // with the corresponding card (the value of the entry will be basically
   // set to 0). If the object crosses the boundary -- start from the next card.
   size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n);
   HeapWord* next_boundary = _array->address_for_index(next_index);
   if (csp() != NULL) {
     if (addr >= csp()->top()) return csp()->top();
     while (next_boundary < addr) {
       while (n <= next_boundary) {
         q = n;
         oop obj = oop(q);
         if (obj->klass_or_null() == NULL) return q;
         n += obj->size();
       }
       assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
       // [q, n) is the block that crosses the boundary.
       alloc_block_work2(&next_boundary, &next_index, q, n);
     }
   } else {
     while (next_boundary < addr) {
       while (n <= next_boundary) {
         q = n;
         oop obj = oop(q);
         if (obj->klass_or_null() == NULL) return q;
         n += _sp->block_size(q);
       }
       assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
       // [q, n) is the block that crosses the boundary.
       alloc_block_work2(&next_boundary, &next_index, q, n);
     }
   }
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 HeapWord* G1BlockOffsetArray::block_start_careful(const void* addr) const {
   assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   // Must read this exactly once because it can be modified by parallel
   // allocation.
   HeapWord* ub = _unallocated_block;
   if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
     assert(ub < _end, "tautology (see above)");
     return ub;
   }
   // Otherwise, find the block start using the table, but taking
   // care (cf block_start_unsafe() above) not to parse any objects/blocks
   // on the cards themsleves.
   size_t index = _array->index_for(addr);
   assert(_array->address_for_index(index) == addr,
          "arg should be start of card");
   HeapWord* q = (HeapWord*)addr;
   uint offset;
   do {
     offset = _array->offset_array(index--);
     q -= offset;
   } while (offset == N_words);
   assert(q <= addr, "block start should be to left of arg");
   return q;
 }
 // Note that the committed size of the covered space may have changed,
 // so the table size might also wish to change.
 void G1BlockOffsetArray::resize(size_t new_word_size) {
   HeapWord* new_end = _bottom + new_word_size;
   if (_end < new_end && !init_to_zero()) {
     // verify that the old and new boundaries are also card boundaries
     assert(_array->is_card_boundary(_end),
            "_end not a card boundary");
     assert(_array->is_card_boundary(new_end),
            "new _end would not be a card boundary");
     // set all the newly added cards
     _array->set_offset_array(_end, new_end, N_words);
   }
   _end = new_end;  // update _end
 }
 void G1BlockOffsetArray::set_region(MemRegion mr) {
   _bottom = mr.start();
   _end = mr.end();
 }
 //
 //              threshold_
 //              |   _index_
 //              v   v
 //      +-------+-------+-------+-------+-------+
 //      | i-1   |   i   | i+1   | i+2   | i+3   |
 //      +-------+-------+-------+-------+-------+
 //       ( ^    ]
 //         block-start
 //
 void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
                                            HeapWord* blk_start, HeapWord* blk_end) {
   // For efficiency, do copy-in/copy-out.
   HeapWord* threshold = *threshold_;
   size_t    index = *index_;
   assert(blk_start != NULL && blk_end > blk_start,
          "phantom block");
   assert(blk_end > threshold, "should be past threshold");
   assert(blk_start <= threshold, "blk_start should be at or before threshold");
   assert(pointer_delta(threshold, blk_start) <= N_words,
          "offset should be <= BlockOffsetSharedArray::N");
   assert(Universe::heap()->is_in_reserved(blk_start),
          "reference must be into the heap");
   assert(Universe::heap()->is_in_reserved(blk_end-1),
          "limit must be within the heap");
   assert(threshold == _array->_reserved.start() + index*N_words,
          "index must agree with threshold");
   DEBUG_ONLY(size_t orig_index = index;)
   // Mark the card that holds the offset into the block.  Note
   // that _next_offset_index and _next_offset_threshold are not
   // updated until the end of this method.
   _array->set_offset_array(index, threshold, blk_start);
   // We need to now mark the subsequent cards that this blk spans.
   // Index of card on which blk ends.
   size_t end_index   = _array->index_for(blk_end - 1);
   // Are there more cards left to be updated?
   if (index + 1 <= end_index) {
     HeapWord* rem_st  = _array->address_for_index(index + 1);
     // Calculate rem_end this way because end_index
     // may be the last valid index in the covered region.
     HeapWord* rem_end = _array->address_for_index(end_index) +  N_words;
     set_remainder_to_point_to_start(rem_st, rem_end);
   }
   index = end_index + 1;
   // Calculate threshold_ this way because end_index
   // may be the last valid index in the covered region.
   threshold = _array->address_for_index(end_index) + N_words;
   assert(threshold >= blk_end, "Incorrect offset threshold");
   // index_ and threshold_ updated here.
   *threshold_ = threshold;
   *index_ = index;
 #ifdef ASSERT
   // The offset can be 0 if the block starts on a boundary.  That
   // is checked by an assertion above.
   size_t start_index = _array->index_for(blk_start);
   HeapWord* boundary    = _array->address_for_index(start_index);
   assert((_array->offset_array(orig_index) == 0 &&
           blk_start == boundary) ||
           (_array->offset_array(orig_index) > 0 &&
          _array->offset_array(orig_index) <= N_words),
          "offset array should have been set");
   for (size_t j = orig_index + 1; j <= end_index; j++) {
     assert(_array->offset_array(j) > 0 &&
            _array->offset_array(j) <=
              (u_char) (N_words+BlockOffsetArray::N_powers-1),
            "offset array should have been set");
   }
 #endif
 }
 bool
 G1BlockOffsetArray::verify_for_object(HeapWord* obj_start,
                                       size_t word_size) const {
   size_t first_card = _array->index_for(obj_start);
   size_t last_card = _array->index_for(obj_start + word_size - 1);
   if (!_array->is_card_boundary(obj_start)) {
     // If the object is not on a card boundary the BOT entry of the
     // first card should point to another object so we should not
     // check that one.
     first_card += 1;
   }
   for (size_t card = first_card; card <= last_card; card += 1) {
     HeapWord* card_addr = _array->address_for_index(card);
     HeapWord* block_start = block_start_const(card_addr);
     if (block_start != obj_start) {
       gclog_or_tty->print_cr("block start: "PTR_FORMAT" is incorrect - "
                              "card index: "SIZE_FORMAT" "
                              "card addr: "PTR_FORMAT" BOT entry: %u "
                              "obj: "PTR_FORMAT" word size: "SIZE_FORMAT" "
                              "cards: ["SIZE_FORMAT","SIZE_FORMAT"]",
                              block_start, card, card_addr,
                              _array->offset_array(card),
                              obj_start, word_size, first_card, last_card);
       return false;
     }
   }
   return true;
 }
 #ifndef PRODUCT
 void
 G1BlockOffsetArray::print_on(outputStream* out) {
   size_t from_index = _array->index_for(_bottom);
   size_t to_index = _array->index_for(_end);
   out->print_cr(">> BOT for area ["PTR_FORMAT","PTR_FORMAT") "
                 "cards ["SIZE_FORMAT","SIZE_FORMAT")",
                 _bottom, _end, from_index, to_index);
   for (size_t i = from_index; i < to_index; ++i) {
     out->print_cr("  entry "SIZE_FORMAT_W(8)" | "PTR_FORMAT" : %3u",
                   i, _array->address_for_index(i),
                   (uint) _array->offset_array(i));
   }
 }
 #endif // !PRODUCT
 //////////////////////////////////////////////////////////////////////
 // G1BlockOffsetArrayContigSpace
 //////////////////////////////////////////////////////////////////////
 HeapWord*
 G1BlockOffsetArrayContigSpace::block_start_unsafe(const void* addr) {
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
   return forward_to_block_containing_addr(q, addr);
 }
 HeapWord*
 G1BlockOffsetArrayContigSpace::
 block_start_unsafe_const(const void* addr) const {
   assert(_bottom <= addr && addr < _end,
          "addr must be covered by this Array");
   HeapWord* q = block_at_or_preceding(addr, true, _next_offset_index-1);
   HeapWord* n = q + _sp->block_size(q);
   return forward_to_block_containing_addr_const(q, n, addr);
 }
 G1BlockOffsetArrayContigSpace::
 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
                               MemRegion mr) :
   G1BlockOffsetArray(array, mr, true)
 {
   _next_offset_threshold = NULL;
   _next_offset_index = 0;
 }
 HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold() {
   assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
          "just checking");
   _next_offset_index = _array->index_for(_bottom);
   _next_offset_index++;
   _next_offset_threshold =
     _array->address_for_index(_next_offset_index);
   return _next_offset_threshold;
 }
 void G1BlockOffsetArrayContigSpace::zero_bottom_entry() {
   assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
          "just checking");
   size_t bottom_index = _array->index_for(_bottom);
   assert(_array->address_for_index(bottom_index) == _bottom,
          "Precondition of call");
   _array->set_offset_array(bottom_index, 0);
 }
 void
 G1BlockOffsetArrayContigSpace::set_for_starts_humongous(HeapWord* new_top) {
   assert(new_top <= _end, "_end should have already been updated");
   // The first BOT entry should have offset 0.
   zero_bottom_entry();
   initialize_threshold();
   alloc_block(_bottom, new_top);
  }
 #ifndef PRODUCT
 void
 G1BlockOffsetArrayContigSpace::print_on(outputStream* out) {
   G1BlockOffsetArray::print_on(out);
   out->print_cr("  next offset threshold: "PTR_FORMAT, _next_offset_threshold);
   out->print_cr("  next offset index:     "SIZE_FORMAT, _next_offset_index);
 }
 #endif // !PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp@2ace1c4ee8da (annotated)

src/share/vm/gc_implementation/g1/g1BlockOffsetTable.cpp