1 /*
2 * Copyright (c) 2013, 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_implementation/g1/g1CardCounts.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
29 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
30 #include "memory/cardTableModRefBS.hpp"
31 #include "services/memTracker.hpp"
32 #include "utilities/copy.hpp"
33
34 void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
35 if (has_count_table()) {
36 assert(from_card_num >= 0 && from_card_num < _committed_max_card_num,
37 err_msg("from card num out of range: "SIZE_FORMAT, from_card_num));
38 assert(from_card_num < to_card_num,
39 err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,
40 from_card_num, to_card_num));
41 assert(to_card_num <= _committed_max_card_num,
42 err_msg("to card num out of range: "
43 "to: "SIZE_FORMAT ", "
44 "max: "SIZE_FORMAT,
45 to_card_num, _committed_max_card_num));
46
47 to_card_num = MIN2(_committed_max_card_num, to_card_num);
48
49 Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));
50 }
51 }
52
53 G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):
54 _g1h(g1h), _card_counts(NULL),
55 _reserved_max_card_num(0), _committed_max_card_num(0),
56 _committed_size(0) {}
57
58 void G1CardCounts::initialize() {
59 assert(_g1h->max_capacity() > 0, "initialization order");
60 assert(_g1h->capacity() == 0, "initialization order");
61
62 if (G1ConcRSHotCardLimit > 0) {
63 // The max value we can store in the counts table is
64 // max_jubyte. Guarantee the value of the hot
65 // threshold limit is no more than this.
66 guarantee(G1ConcRSHotCardLimit <= max_jubyte, "sanity");
67
68 _ct_bs = _g1h->g1_barrier_set();
69 _ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());
70
71 // Allocate/Reserve the counts table
72 size_t reserved_bytes = _g1h->max_capacity();
73 _reserved_max_card_num = reserved_bytes >> CardTableModRefBS::card_shift;
74
75 size_t reserved_size = _reserved_max_card_num * sizeof(jbyte);
76 ReservedSpace rs(ReservedSpace::allocation_align_size_up(reserved_size));
77 if (!rs.is_reserved()) {
78 warning("Could not reserve enough space for the card counts table");
79 guarantee(!has_reserved_count_table(), "should be NULL");
80 return;
81 }
82
83 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
84
85 _card_counts_storage.initialize(rs, 0);
86 _card_counts = (jubyte*) _card_counts_storage.low();
87 }
88 }
89
90 void G1CardCounts::resize(size_t heap_capacity) {
91 // Expand the card counts table to handle a heap with the given capacity.
92
93 if (!has_reserved_count_table()) {
94 // Don't expand if we failed to reserve the card counts table.
95 return;
96 }
97
98 assert(_committed_size ==
99 ReservedSpace::allocation_align_size_up(_committed_size),
100 err_msg("Unaligned? committed_size: " SIZE_FORMAT, _committed_size));
101
102 // Verify that the committed space for the card counts matches our
103 // committed max card num. Note for some allocation alignments, the
104 // amount of space actually committed for the counts table will be able
105 // to span more cards than the number spanned by the maximum heap.
106 size_t prev_committed_size = _committed_size;
107 size_t prev_committed_card_num = committed_to_card_num(prev_committed_size);
108
109 assert(prev_committed_card_num == _committed_max_card_num,
110 err_msg("Card mismatch: "
111 "prev: " SIZE_FORMAT ", "
112 "committed: "SIZE_FORMAT", "
113 "reserved: "SIZE_FORMAT,
114 prev_committed_card_num, _committed_max_card_num, _reserved_max_card_num));
115
116 size_t new_size = (heap_capacity >> CardTableModRefBS::card_shift) * sizeof(jbyte);
117 size_t new_committed_size = ReservedSpace::allocation_align_size_up(new_size);
118 size_t new_committed_card_num = committed_to_card_num(new_committed_size);
119
120 if (_committed_max_card_num < new_committed_card_num) {
121 // we need to expand the backing store for the card counts
122 size_t expand_size = new_committed_size - prev_committed_size;
123
124 if (!_card_counts_storage.expand_by(expand_size)) {
125 warning("Card counts table backing store commit failure");
126 return;
127 }
128 assert(_card_counts_storage.committed_size() == new_committed_size,
129 "expansion commit failure");
130
131 _committed_size = new_committed_size;
132 _committed_max_card_num = new_committed_card_num;
133
134 clear_range(prev_committed_card_num, _committed_max_card_num);
135 }
136 }
137
138 uint G1CardCounts::add_card_count(jbyte* card_ptr) {
139 // Returns the number of times the card has been refined.
140 // If we failed to reserve/commit the counts table, return 0.
141 // If card_ptr is beyond the committed end of the counts table,
142 // return 0.
143 // Otherwise return the actual count.
144 // Unless G1ConcRSHotCardLimit has been set appropriately,
145 // returning 0 will result in the card being considered
146 // cold and will be refined immediately.
147 uint count = 0;
148 if (has_count_table()) {
149 size_t card_num = ptr_2_card_num(card_ptr);
150 if (card_num < _committed_max_card_num) {
151 count = (uint) _card_counts[card_num];
152 if (count < G1ConcRSHotCardLimit) {
153 _card_counts[card_num] =
154 (jubyte)(MIN2((uintx)(_card_counts[card_num] + 1), G1ConcRSHotCardLimit));
155 }
156 }
157 }
158 return count;
159 }
160
161 bool G1CardCounts::is_hot(uint count) {
162 return (count >= G1ConcRSHotCardLimit);
163 }
164
165 void G1CardCounts::clear_region(HeapRegion* hr) {
166 assert(!hr->isHumongous(), "Should have been cleared");
167 if (has_count_table()) {
168 HeapWord* bottom = hr->bottom();
169
170 // We use the last address in hr as hr could be the
171 // last region in the heap. In which case trying to find
172 // the card for hr->end() will be an OOB access to the
173 // card table.
174 HeapWord* last = hr->end() - 1;
175 assert(_g1h->g1_committed().contains(last),
176 err_msg("last not in committed: "
177 "last: " PTR_FORMAT ", "
178 "committed: [" PTR_FORMAT ", " PTR_FORMAT ")",
179 last,
180 _g1h->g1_committed().start(),
181 _g1h->g1_committed().end()));
182
183 const jbyte* from_card_ptr = _ct_bs->byte_for_const(bottom);
184 const jbyte* last_card_ptr = _ct_bs->byte_for_const(last);
185
186 #ifdef ASSERT
187 HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);
188 assert(start_addr == hr->bottom(), "alignment");
189 HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);
190 assert((last_addr + CardTableModRefBS::card_size_in_words) == hr->end(), "alignment");
191 #endif // ASSERT
192
193 // Clear the counts for the (exclusive) card range.
194 size_t from_card_num = ptr_2_card_num(from_card_ptr);
195 size_t to_card_num = ptr_2_card_num(last_card_ptr) + 1;
196 clear_range(from_card_num, to_card_num);
197 }
198 }
199
200 void G1CardCounts::clear_all() {
201 assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");
202 clear_range((size_t)0, _committed_max_card_num);
203 }
204
205 G1CardCounts::~G1CardCounts() {
206 if (has_reserved_count_table()) {
207 _card_counts_storage.release();
208 }
209 }
210