1 /* 2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc/g1/g1CardTable.hpp" 27 #include "gc/g1/g1CollectedHeap.inline.hpp" 28 #include "gc/shared/memset_with_concurrent_readers.hpp" 29 #include "logging/log.hpp" 30 #include "runtime/atomic.hpp" 31 #include "runtime/orderAccess.hpp" 32 33 void G1CardTable::g1_mark_as_young(const MemRegion& mr) { 34 CardValue *const first = byte_for(mr.start()); 35 CardValue *const last = byte_after(mr.last()); 36 37 memset_with_concurrent_readers(first, g1_young_gen, last - first); 38 } 39 40 #ifndef PRODUCT 41 void G1CardTable::verify_g1_young_region(MemRegion mr) { 42 verify_region(mr, g1_young_gen, true); 43 } 44 #endif 45 46 void G1CardTableChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) { 47 // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter. 48 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords); 49 _card_table->clear(mr); 50 } 51 52 void G1CardTable::initialize(G1RegionToSpaceMapper* mapper) { 53 mapper->set_mapping_changed_listener(&_listener); 54 55 _byte_map_size = mapper->reserved().byte_size(); 56 57 _guard_index = cards_required(_whole_heap.word_size()) - 1; 58 _last_valid_index = _guard_index - 1; 59 60 HeapWord* low_bound = _whole_heap.start(); 61 HeapWord* high_bound = _whole_heap.end(); 62 63 _cur_covered_regions = 1; 64 _covered[0] = _whole_heap; 65 66 _byte_map = (CardValue*) mapper->reserved().start(); 67 _byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift); 68 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map"); 69 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map"); 70 71 log_trace(gc, barrier)("G1CardTable::G1CardTable: "); 72 log_trace(gc, barrier)(" &_byte_map[0]: " INTPTR_FORMAT " &_byte_map[_last_valid_index]: " INTPTR_FORMAT, 73 p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index])); 74 log_trace(gc, barrier)(" _byte_map_base: " INTPTR_FORMAT, p2i(_byte_map_base)); 75 } 76 77 bool G1CardTable::is_in_young(oop obj) const { 78 volatile CardValue* p = byte_for(obj); 79 return *p == G1CardTable::g1_young_card_val(); 80 }