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 bool G1CardTable::mark_card_deferred(size_t card_index) {
34 CardValue val = _byte_map[card_index];
35 // It's already processed
36 if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
37 return false;
38 }
39
40 // Cached bit can be installed either on a clean card or on a claimed card.
41 CardValue new_val = val;
42 if (val == clean_card_val()) {
43 new_val = deferred_card_val();
44 } else {
45 if (val & claimed_card_val()) {
46 new_val = val | deferred_card_val();
47 }
48 }
49 if (new_val != val) {
50 Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
51 }
52 return true;
53 }
54
55 void G1CardTable::g1_mark_as_young(const MemRegion& mr) {
56 CardValue *const first = byte_for(mr.start());
57 CardValue *const last = byte_after(mr.last());
58
59 memset_with_concurrent_readers(first, g1_young_gen, last - first);
60 }
61
62 #ifndef PRODUCT
63 void G1CardTable::verify_g1_young_region(MemRegion mr) {
64 // G1FastWriteBarrier does not use the value G1CardTable::g1_young_gen
65 // for cards. Cards for a young region can be dirty or clean, and they are
66 // never scanned. So there is nothing to verify.
67 if (!G1FastWriteBarrier) {
68 verify_region(mr, g1_young_gen, true);
69 }
70 }
71
72 void G1CardTable::verfiy_claimed_dirty_region(MemRegion mr) {
73 // _ct->print_content_for_mr(mr, tty);
74 // All cards should be either "claimed" or "claimed and deferred".
75 const CardValue claimed_val = dirty_card_val() | claimed_card_val();
76 const CardValue deferred_val = claimed_val | deferred_card_val();
77 CardValue* start = byte_for(mr.start());
78 CardValue* end = byte_for(mr.last());
79 bool failures = false;
80 for (CardValue* curr = start; curr <= end; ++curr) {
81 CardValue curr_val = *curr;
82 bool failed = (curr_val != claimed_val && curr_val != deferred_val);
83 if (failed) {
84 if (!failures) {
85 log_error(gc, verify)("== CT verification failed: [" INTPTR_FORMAT "," INTPTR_FORMAT "]", p2i(start), p2i(end));
86 log_error(gc, verify)("== expecting value: %d or %d", claimed_val, deferred_val);
87 failures = true;
88 }
89 log_error(gc, verify)("== card " PTR_FORMAT " [" PTR_FORMAT "," PTR_FORMAT "], val: %d",
90 p2i(curr), p2i(addr_for(curr)),
91 p2i((HeapWord*) (((size_t) addr_for(curr)) + card_size)),
92 (int) curr_val);
93 }
94 }
95 guarantee(!failures, "there should be no failure");
96 }
97 #endif
98
99 void G1CardTableChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
100 // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.
101 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
102 _card_table->clear(mr);
103 }
104
105 void G1CardTable::initialize(G1RegionToSpaceMapper* mapper) {
106 mapper->set_mapping_changed_listener(&_listener);
107
108 _byte_map_size = mapper->reserved().byte_size();
109
110 _guard_index = cards_required(_whole_heap.word_size()) - 1;
111 _last_valid_index = _guard_index - 1;
112
113 HeapWord* low_bound = _whole_heap.start();
114 HeapWord* high_bound = _whole_heap.end();
115
116 _cur_covered_regions = 1;
117 _covered[0] = _whole_heap;
118
119 _byte_map = (CardValue*) mapper->reserved().start();
120 _byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
121 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
122 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
123
124 log_trace(gc, barrier)("G1CardTable::G1CardTable: ");
125 log_trace(gc, barrier)(" &_byte_map[0]: " INTPTR_FORMAT " &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
126 p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));
127 log_trace(gc, barrier)(" _byte_map_base: " INTPTR_FORMAT, p2i(_byte_map_base));
128 }
129
130 bool G1CardTable::is_in_young(oop obj) const {
131 if (G1FastWriteBarrier) {
132 return G1CollectedHeap::heap()->heap_region_containing(obj)->is_young();
133 } else {
134 volatile CardValue* p = byte_for(obj);
135 return *p == G1CardTable::g1_young_card_val();
136 }
137 }