506 lines
20 KiB
C++
506 lines
20 KiB
C++
/*
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* Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
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#include "gc_implementation/g1/heapRegion.hpp"
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#include "memory/space.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/java.hpp"
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#include "services/memTracker.hpp"
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//////////////////////////////////////////////////////////////////////
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// G1BlockOffsetSharedArray
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//////////////////////////////////////////////////////////////////////
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G1BlockOffsetSharedArray::G1BlockOffsetSharedArray(MemRegion heap, G1RegionToSpaceMapper* storage) :
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_reserved(), _end(NULL), _listener(), _offset_array(NULL) {
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_reserved = heap;
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_end = NULL;
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MemRegion bot_reserved = storage->reserved();
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_offset_array = (u_char*)bot_reserved.start();
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_end = _reserved.end();
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storage->set_mapping_changed_listener(&_listener);
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if (TraceBlockOffsetTable) {
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gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: ");
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gclog_or_tty->print_cr(" "
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" rs.base(): " PTR_FORMAT
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" rs.size(): " SIZE_FORMAT
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" rs end(): " PTR_FORMAT,
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p2i(bot_reserved.start()), bot_reserved.byte_size(), p2i(bot_reserved.end()));
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}
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}
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bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
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assert(p >= _reserved.start(), "just checking");
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size_t delta = pointer_delta(p, _reserved.start());
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return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
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}
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//////////////////////////////////////////////////////////////////////
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// G1BlockOffsetArray
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//////////////////////////////////////////////////////////////////////
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G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array,
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MemRegion mr) :
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G1BlockOffsetTable(mr.start(), mr.end()),
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_unallocated_block(_bottom),
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_array(array), _gsp(NULL) {
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assert(_bottom <= _end, "arguments out of order");
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}
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void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) {
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_gsp = sp;
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}
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// The arguments follow the normal convention of denoting
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// a right-open interval: [start, end)
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void
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G1BlockOffsetArray:: set_remainder_to_point_to_start(HeapWord* start, HeapWord* end) {
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if (start >= end) {
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// The start address is equal to the end address (or to
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// the right of the end address) so there are not cards
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// that need to be updated..
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return;
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}
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// Write the backskip value for each region.
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//
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// offset
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// card 2nd 3rd
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// | +- 1st | |
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// v v v v
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
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// |x|0|0|0|0|0|0|0|1|1|1|1|1|1| ... |1|1|1|1|2|2|2|2|2|2| ...
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// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-
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// 11 19 75
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// 12
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//
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// offset card is the card that points to the start of an object
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// x - offset value of offset card
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// 1st - start of first logarithmic region
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// 0 corresponds to logarithmic value N_words + 0 and 2**(3 * 0) = 1
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// 2nd - start of second logarithmic region
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// 1 corresponds to logarithmic value N_words + 1 and 2**(3 * 1) = 8
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// 3rd - start of third logarithmic region
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// 2 corresponds to logarithmic value N_words + 2 and 2**(3 * 2) = 64
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//
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// integer below the block offset entry is an example of
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// the index of the entry
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//
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// Given an address,
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// Find the index for the address
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// Find the block offset table entry
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// Convert the entry to a back slide
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// (e.g., with today's, offset = 0x81 =>
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// back slip = 2**(3*(0x81 - N_words)) = 2**3) = 8
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// Move back N (e.g., 8) entries and repeat with the
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// value of the new entry
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//
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size_t start_card = _array->index_for(start);
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size_t end_card = _array->index_for(end-1);
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assert(start ==_array->address_for_index(start_card), "Precondition");
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assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
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set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
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}
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// Unlike the normal convention in this code, the argument here denotes
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// a closed, inclusive interval: [start_card, end_card], cf set_remainder_to_point_to_start()
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// above.
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void
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G1BlockOffsetArray::set_remainder_to_point_to_start_incl(size_t start_card, size_t end_card) {
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if (start_card > end_card) {
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return;
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}
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assert(start_card > _array->index_for(_bottom), "Cannot be first card");
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assert(_array->offset_array(start_card-1) <= N_words,
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"Offset card has an unexpected value");
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size_t start_card_for_region = start_card;
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u_char offset = max_jubyte;
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for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
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// -1 so that the the card with the actual offset is counted. Another -1
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// so that the reach ends in this region and not at the start
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// of the next.
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size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
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offset = N_words + i;
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if (reach >= end_card) {
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_array->set_offset_array(start_card_for_region, end_card, offset);
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start_card_for_region = reach + 1;
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break;
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}
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_array->set_offset_array(start_card_for_region, reach, offset);
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start_card_for_region = reach + 1;
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}
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assert(start_card_for_region > end_card, "Sanity check");
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DEBUG_ONLY(check_all_cards(start_card, end_card);)
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}
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// The card-interval [start_card, end_card] is a closed interval; this
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// is an expensive check -- use with care and only under protection of
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// suitable flag.
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void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const {
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if (end_card < start_card) {
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return;
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}
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guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
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for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
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u_char entry = _array->offset_array(c);
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if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
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guarantee(entry > N_words,
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err_msg("Should be in logarithmic region - "
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"entry: %u, "
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"_array->offset_array(c): %u, "
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"N_words: %u",
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(uint)entry, (uint)_array->offset_array(c), (uint)N_words));
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}
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size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
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size_t landing_card = c - backskip;
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guarantee(landing_card >= (start_card - 1), "Inv");
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if (landing_card >= start_card) {
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guarantee(_array->offset_array(landing_card) <= entry,
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err_msg("Monotonicity - landing_card offset: %u, "
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"entry: %u",
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(uint)_array->offset_array(landing_card), (uint)entry));
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} else {
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guarantee(landing_card == start_card - 1, "Tautology");
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// Note that N_words is the maximum offset value
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guarantee(_array->offset_array(landing_card) <= N_words,
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err_msg("landing card offset: %u, "
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"N_words: %u",
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(uint)_array->offset_array(landing_card), (uint)N_words));
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}
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}
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}
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HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) {
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assert(_bottom <= addr && addr < _end,
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"addr must be covered by this Array");
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// Must read this exactly once because it can be modified by parallel
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// allocation.
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HeapWord* ub = _unallocated_block;
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if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
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assert(ub < _end, "tautology (see above)");
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return ub;
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}
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// Otherwise, find the block start using the table.
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HeapWord* q = block_at_or_preceding(addr, false, 0);
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return forward_to_block_containing_addr(q, addr);
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}
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// This duplicates a little code from the above: unavoidable.
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HeapWord*
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G1BlockOffsetArray::block_start_unsafe_const(const void* addr) const {
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assert(_bottom <= addr && addr < _end,
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"addr must be covered by this Array");
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// Must read this exactly once because it can be modified by parallel
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// allocation.
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HeapWord* ub = _unallocated_block;
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if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) {
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assert(ub < _end, "tautology (see above)");
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return ub;
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}
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// Otherwise, find the block start using the table.
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HeapWord* q = block_at_or_preceding(addr, false, 0);
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HeapWord* n = q + block_size(q);
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return forward_to_block_containing_addr_const(q, n, addr);
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}
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HeapWord*
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G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q,
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HeapWord* n,
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const void* addr) {
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// We're not in the normal case. We need to handle an important subcase
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// here: LAB allocation. An allocation previously recorded in the
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// offset table was actually a lab allocation, and was divided into
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// several objects subsequently. Fix this situation as we answer the
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// query, by updating entries as we cross them.
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// If the fist object's end q is at the card boundary. Start refining
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// with the corresponding card (the value of the entry will be basically
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// set to 0). If the object crosses the boundary -- start from the next card.
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size_t n_index = _array->index_for(n);
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size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n);
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// Calculate a consistent next boundary. If "n" is not at the boundary
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// already, step to the boundary.
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HeapWord* next_boundary = _array->address_for_index(n_index) +
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(n_index == next_index ? 0 : N_words);
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assert(next_boundary <= _array->_end,
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err_msg("next_boundary is beyond the end of the covered region "
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" next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
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p2i(next_boundary), p2i(_array->_end)));
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if (addr >= gsp()->top()) return gsp()->top();
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while (next_boundary < addr) {
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while (n <= next_boundary) {
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q = n;
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oop obj = oop(q);
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if (obj->klass_or_null() == NULL) return q;
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n += block_size(q);
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}
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assert(q <= next_boundary && n > next_boundary, "Consequence of loop");
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// [q, n) is the block that crosses the boundary.
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alloc_block_work2(&next_boundary, &next_index, q, n);
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}
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return forward_to_block_containing_addr_const(q, n, addr);
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}
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// Note that the committed size of the covered space may have changed,
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// so the table size might also wish to change.
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void G1BlockOffsetArray::resize(size_t new_word_size) {
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HeapWord* new_end = _bottom + new_word_size;
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_end = new_end; // update _end
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}
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//
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// threshold_
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// | _index_
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// v v
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// +-------+-------+-------+-------+-------+
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// | i-1 | i | i+1 | i+2 | i+3 |
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// +-------+-------+-------+-------+-------+
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// ( ^ ]
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// block-start
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//
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void G1BlockOffsetArray::alloc_block_work2(HeapWord** threshold_, size_t* index_,
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HeapWord* blk_start, HeapWord* blk_end) {
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// For efficiency, do copy-in/copy-out.
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HeapWord* threshold = *threshold_;
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size_t index = *index_;
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assert(blk_start != NULL && blk_end > blk_start,
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"phantom block");
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assert(blk_end > threshold, "should be past threshold");
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assert(blk_start <= threshold, "blk_start should be at or before threshold");
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assert(pointer_delta(threshold, blk_start) <= N_words,
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"offset should be <= BlockOffsetSharedArray::N");
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assert(Universe::heap()->is_in_reserved(blk_start),
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"reference must be into the heap");
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assert(Universe::heap()->is_in_reserved(blk_end-1),
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"limit must be within the heap");
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assert(threshold == _array->_reserved.start() + index*N_words,
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"index must agree with threshold");
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DEBUG_ONLY(size_t orig_index = index;)
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// Mark the card that holds the offset into the block. Note
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// that _next_offset_index and _next_offset_threshold are not
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// updated until the end of this method.
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_array->set_offset_array(index, threshold, blk_start);
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// We need to now mark the subsequent cards that this blk spans.
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// Index of card on which blk ends.
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size_t end_index = _array->index_for(blk_end - 1);
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// Are there more cards left to be updated?
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if (index + 1 <= end_index) {
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HeapWord* rem_st = _array->address_for_index(index + 1);
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// Calculate rem_end this way because end_index
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// may be the last valid index in the covered region.
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HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
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set_remainder_to_point_to_start(rem_st, rem_end);
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}
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index = end_index + 1;
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// Calculate threshold_ this way because end_index
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// may be the last valid index in the covered region.
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threshold = _array->address_for_index(end_index) + N_words;
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assert(threshold >= blk_end, "Incorrect offset threshold");
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// index_ and threshold_ updated here.
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*threshold_ = threshold;
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*index_ = index;
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#ifdef ASSERT
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// The offset can be 0 if the block starts on a boundary. That
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// is checked by an assertion above.
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size_t start_index = _array->index_for(blk_start);
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HeapWord* boundary = _array->address_for_index(start_index);
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assert((_array->offset_array(orig_index) == 0 &&
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blk_start == boundary) ||
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(_array->offset_array(orig_index) > 0 &&
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_array->offset_array(orig_index) <= N_words),
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err_msg("offset array should have been set - "
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"orig_index offset: %u, "
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"blk_start: " PTR_FORMAT ", "
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"boundary: " PTR_FORMAT,
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(uint)_array->offset_array(orig_index),
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p2i(blk_start), p2i(boundary)));
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for (size_t j = orig_index + 1; j <= end_index; j++) {
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assert(_array->offset_array(j) > 0 &&
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_array->offset_array(j) <=
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(u_char) (N_words+BlockOffsetArray::N_powers-1),
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err_msg("offset array should have been set - "
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"%u not > 0 OR %u not <= %u",
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(uint) _array->offset_array(j),
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(uint) _array->offset_array(j),
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(uint) (N_words+BlockOffsetArray::N_powers-1)));
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}
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#endif
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}
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void G1BlockOffsetArray::verify() const {
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assert(gsp()->bottom() < gsp()->top(), "Only non-empty regions should be verified.");
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size_t start_card = _array->index_for(gsp()->bottom());
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size_t end_card = _array->index_for(gsp()->top() - 1);
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for (size_t current_card = start_card; current_card < end_card; current_card++) {
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u_char entry = _array->offset_array(current_card);
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if (entry < N_words) {
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// The entry should point to an object before the current card. Verify that
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// it is possible to walk from that object in to the current card by just
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// iterating over the objects following it.
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HeapWord* card_address = _array->address_for_index(current_card);
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HeapWord* obj_end = card_address - entry;
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while (obj_end < card_address) {
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HeapWord* obj = obj_end;
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size_t obj_size = block_size(obj);
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obj_end = obj + obj_size;
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guarantee(obj_end > obj && obj_end <= gsp()->top(),
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err_msg("Invalid object end. obj: " PTR_FORMAT " obj_size: " SIZE_FORMAT " obj_end: " PTR_FORMAT " top: " PTR_FORMAT,
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p2i(obj), obj_size, p2i(obj_end), p2i(gsp()->top())));
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}
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} else {
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// Because we refine the BOT based on which cards are dirty there is not much we can verify here.
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// We need to make sure that we are going backwards and that we don't pass the start of the
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// corresponding heap region. But that is about all we can verify.
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size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
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guarantee(backskip >= 1, "Must be going back at least one card.");
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size_t max_backskip = current_card - start_card;
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guarantee(backskip <= max_backskip,
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err_msg("Going backwards beyond the start_card. start_card: " SIZE_FORMAT " current_card: " SIZE_FORMAT " backskip: " SIZE_FORMAT,
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start_card, current_card, backskip));
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HeapWord* backskip_address = _array->address_for_index(current_card - backskip);
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guarantee(backskip_address >= gsp()->bottom(),
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err_msg("Going backwards beyond bottom of the region: bottom: " PTR_FORMAT ", backskip_address: " PTR_FORMAT,
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p2i(gsp()->bottom()), p2i(backskip_address)));
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}
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}
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}
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#ifndef PRODUCT
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void
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G1BlockOffsetArray::print_on(outputStream* out) {
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size_t from_index = _array->index_for(_bottom);
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size_t to_index = _array->index_for(_end);
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out->print_cr(">> BOT for area ["PTR_FORMAT","PTR_FORMAT") "
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"cards ["SIZE_FORMAT","SIZE_FORMAT")",
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p2i(_bottom), p2i(_end), from_index, to_index);
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for (size_t i = from_index; i < to_index; ++i) {
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out->print_cr(" entry "SIZE_FORMAT_W(8)" | "PTR_FORMAT" : %3u",
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i, p2i(_array->address_for_index(i)),
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(uint) _array->offset_array(i));
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}
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}
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#endif // !PRODUCT
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//////////////////////////////////////////////////////////////////////
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// G1BlockOffsetArrayContigSpace
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//////////////////////////////////////////////////////////////////////
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HeapWord*
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|
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 + block_size(q);
|
|
return forward_to_block_containing_addr_const(q, n, addr);
|
|
}
|
|
|
|
G1BlockOffsetArrayContigSpace::
|
|
G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array,
|
|
MemRegion mr) :
|
|
G1BlockOffsetArray(array, mr)
|
|
{
|
|
_next_offset_threshold = NULL;
|
|
_next_offset_index = 0;
|
|
}
|
|
|
|
HeapWord* G1BlockOffsetArrayContigSpace::initialize_threshold_raw() {
|
|
assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
|
|
"just checking");
|
|
_next_offset_index = _array->index_for_raw(_bottom);
|
|
_next_offset_index++;
|
|
_next_offset_threshold =
|
|
_array->address_for_index_raw(_next_offset_index);
|
|
return _next_offset_threshold;
|
|
}
|
|
|
|
void G1BlockOffsetArrayContigSpace::zero_bottom_entry_raw() {
|
|
assert(!Universe::heap()->is_in_reserved(_array->_offset_array),
|
|
"just checking");
|
|
size_t bottom_index = _array->index_for_raw(_bottom);
|
|
assert(_array->address_for_index_raw(bottom_index) == _bottom,
|
|
"Precondition of call");
|
|
_array->set_offset_array_raw(bottom_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::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.
|
|
reset_bot();
|
|
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, p2i(_next_offset_threshold));
|
|
out->print_cr(" next offset index: "SIZE_FORMAT, _next_offset_index);
|
|
}
|
|
#endif // !PRODUCT
|