1 /*
2 * Copyright (c) 2001, 2019, 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/heapRegion.hpp"
27 #include "gc/g1/heapRegionBounds.inline.hpp"
28 #include "gc/g1/heapRegionRemSet.hpp"
29 #include "gc/g1/sparsePRT.hpp"
30 #include "gc/shared/cardTableBarrierSet.hpp"
31 #include "gc/shared/space.inline.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "runtime/mutexLocker.hpp"
34
35 // Check that the size of the SparsePRTEntry is evenly divisible by the maximum
36 // member type to avoid SIGBUS when accessing them.
37 STATIC_ASSERT(sizeof(SparsePRTEntry) % sizeof(int) == 0);
38
39 void SparsePRTEntry::init(RegionIdx_t region_ind) {
40 // Check that the card array element type can represent all cards in the region.
41 // Choose a large SparsePRTEntry::card_elem_t (e.g. CardIdx_t) if required.
42 assert(((size_t)1 << (sizeof(SparsePRTEntry::card_elem_t) * BitsPerByte)) *
43 G1CardTable::card_size >= HeapRegionBounds::max_size(), "precondition");
44 assert(G1RSetSparseRegionEntries > 0, "precondition");
45 _region_ind = region_ind;
46 _next_index = RSHashTable::NullEntry;
47 _next_null = 0;
48 }
49
50 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
51 for (int i = 0; i < num_valid_cards(); i++) {
52 if (card(i) == card_index) {
53 return true;
54 }
55 }
56 return false;
57 }
58
59 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
60 for (int i = 0; i < num_valid_cards(); i++) {
61 if (card(i) == card_index) {
62 return found;
63 }
64 }
65 if (num_valid_cards() < cards_num() - 1) {
66 _cards[_next_null] = (card_elem_t)card_index;
67 _next_null++;
68 return added;
69 }
70 // Otherwise, we're full.
71 return overflow;
72 }
73
74 void SparsePRTEntry::copy_cards(card_elem_t* cards) const {
75 memcpy(cards, _cards, cards_num() * sizeof(card_elem_t));
76 }
77
78 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
79 copy_cards(e->_cards);
80 assert(_next_null >= 0, "invariant");
81 assert(_next_null <= cards_num(), "invariant");
82 e->_next_null = _next_null;
83 }
84
85 // ----------------------------------------------------------------------
86
87 float RSHashTable::TableOccupancyFactor = 0.5f;
88
89 RSHashTable::RSHashTable(size_t capacity) :
90 _num_entries(0),
91 _capacity(capacity),
92 _capacity_mask(capacity-1),
93 _occupied_entries(0),
94 _occupied_cards(0),
95 _entries(NULL),
96 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)),
97 _free_region(0),
98 _free_list(NullEntry)
99 {
100 _num_entries = (capacity * TableOccupancyFactor) + 1;
101 _entries = (SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, _num_entries * SparsePRTEntry::size(), mtGC);
102 clear();
103 }
104
105 RSHashTable::~RSHashTable() {
106 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries);
107 FREE_C_HEAP_ARRAY(int, _buckets);
108 }
109
110 void RSHashTable::clear() {
111 _occupied_entries = 0;
112 _occupied_cards = 0;
113 guarantee(_entries != NULL, "INV");
114 guarantee(_buckets != NULL, "INV");
115
116 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
117 "_capacity too large");
118
119 // This will put -1 == NullEntry in the key field of all entries.
120 memset((void*)_entries, NullEntry, _num_entries * SparsePRTEntry::size());
121 memset((void*)_buckets, NullEntry, _capacity * sizeof(int));
122 _free_list = NullEntry;
123 _free_region = 0;
124 }
125
126 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
127 SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
128 assert(e != NULL && e->r_ind() == region_ind,
129 "Postcondition of call above.");
130 SparsePRTEntry::AddCardResult res = e->add_card(card_index);
131 if (res == SparsePRTEntry::added) _occupied_cards++;
132 assert(e->num_valid_cards() > 0, "Postcondition");
133 return res != SparsePRTEntry::overflow;
134 }
135
136 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const {
137 int ind = (int) (region_ind & capacity_mask());
138 int cur_ind = _buckets[ind];
139 SparsePRTEntry* cur;
140 while (cur_ind != NullEntry &&
141 (cur = entry(cur_ind))->r_ind() != region_ind) {
142 cur_ind = cur->next_index();
143 }
144
145 if (cur_ind == NullEntry) return NULL;
146 // Otherwise...
147 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
148 assert(cur->num_valid_cards() > 0, "Inv");
149 return cur;
150 }
151
152 bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
153 int ind = (int) (region_ind & capacity_mask());
154 int* prev_loc = &_buckets[ind];
155 int cur_ind = *prev_loc;
156 SparsePRTEntry* cur;
157 while (cur_ind != NullEntry &&
158 (cur = entry(cur_ind))->r_ind() != region_ind) {
159 prev_loc = cur->next_index_addr();
160 cur_ind = *prev_loc;
161 }
162
163 if (cur_ind == NullEntry) return false;
164 // Otherwise, splice out "cur".
165 *prev_loc = cur->next_index();
166 _occupied_cards -= cur->num_valid_cards();
167 free_entry(cur_ind);
168 _occupied_entries--;
169 return true;
170 }
171
172 SparsePRTEntry*
173 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
174 SparsePRTEntry* res = get_entry(region_ind);
175 if (res == NULL) {
176 int new_ind = alloc_entry();
177 res = entry(new_ind);
178 res->init(region_ind);
179 // Insert at front.
180 int ind = (int) (region_ind & capacity_mask());
181 res->set_next_index(_buckets[ind]);
182 _buckets[ind] = new_ind;
183 _occupied_entries++;
184 }
185 return res;
186 }
187
188 int RSHashTable::alloc_entry() {
189 int res;
190 if (_free_list != NullEntry) {
191 res = _free_list;
192 _free_list = entry(res)->next_index();
193 return res;
194 } else if ((size_t)_free_region < _num_entries) {
195 res = _free_region;
196 _free_region++;
197 return res;
198 } else {
199 return NullEntry;
200 }
201 }
202
203 void RSHashTable::free_entry(int fi) {
204 entry(fi)->set_next_index(_free_list);
205 _free_list = fi;
206 }
207
208 void RSHashTable::add_entry(SparsePRTEntry* e) {
209 assert(e->num_valid_cards() > 0, "Precondition.");
210 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
211 e->copy_cards(e2);
212 _occupied_cards += e2->num_valid_cards();
213 assert(e2->num_valid_cards() > 0, "Postcondition.");
214 }
215
216 CardIdx_t RSHashTableIter::find_first_card_in_list() {
217 while (_bl_ind != RSHashTable::NullEntry) {
218 SparsePRTEntry* sparse_entry = _rsht->entry(_bl_ind);
219 if (sparse_entry->num_valid_cards() > 0) {
220 return sparse_entry->card(0);
221 } else {
222 _bl_ind = sparse_entry->next_index();
223 }
224 }
225 // Otherwise, none found:
226 return NoCardFound;
227 }
228
229 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) {
230 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci;
231 }
232
233 bool RSHashTableIter::has_next(size_t& card_index) {
234 _card_ind++;
235 if (_bl_ind >= 0) {
236 SparsePRTEntry* e = _rsht->entry(_bl_ind);
237 if (_card_ind < e->num_valid_cards()) {
238 CardIdx_t ci = e->card(_card_ind);
239 card_index = compute_card_ind(ci);
240 return true;
241 }
242 }
243
244 // Otherwise, must find the next valid entry.
245 _card_ind = 0;
246
247 if (_bl_ind != RSHashTable::NullEntry) {
248 _bl_ind = _rsht->entry(_bl_ind)->next_index();
249 CardIdx_t ci = find_first_card_in_list();
250 if (ci != NoCardFound) {
251 card_index = compute_card_ind(ci);
252 return true;
253 }
254 }
255 // If we didn't return above, must go to the next non-null table index.
256 _tbl_ind++;
257 while ((size_t)_tbl_ind < _rsht->capacity()) {
258 _bl_ind = _rsht->_buckets[_tbl_ind];
259 CardIdx_t ci = find_first_card_in_list();
260 if (ci != NoCardFound) {
261 card_index = compute_card_ind(ci);
262 return true;
263 }
264 // Otherwise, try next entry.
265 _tbl_ind++;
266 }
267 // Otherwise, there were no entry.
268 return false;
269 }
270
271 bool RSHashTableBucketIter::has_next(SparsePRTEntry*& entry) {
272 while (_bl_ind == RSHashTable::NullEntry) {
273 if (_tbl_ind == (int)_rsht->capacity() - 1) {
274 return false;
275 }
276 _tbl_ind++;
277 _bl_ind = _rsht->_buckets[_tbl_ind];
278 }
279 entry = _rsht->entry(_bl_ind);
280 _bl_ind = entry->next_index();
281 return true;
282 }
283
284 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
285 SparsePRTEntry* e = get_entry(region_index);
286 return (e != NULL && e->contains_card(card_index));
287 }
288
289 size_t RSHashTable::mem_size() const {
290 return sizeof(RSHashTable) +
291 _num_entries * (SparsePRTEntry::size() + sizeof(int));
292 }
293
294 // ----------------------------------------------------------------------
295
296 SparsePRT::SparsePRT() :
297 _table(new RSHashTable(InitialCapacity)) {
298 }
299
300
301 SparsePRT::~SparsePRT() {
302 delete _table;
303 }
304
305
306 size_t SparsePRT::mem_size() const {
307 // We ignore "_cur" here, because it either = _next, or else it is
308 // on the deleted list.
309 return sizeof(SparsePRT) + _table->mem_size();
310 }
311
312 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
313 if (_table->should_expand()) {
314 expand();
315 }
316 return _table->add_card(region_id, card_index);
317 }
318
319 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
320 return _table->get_entry(region_id);
321 }
322
323 bool SparsePRT::delete_entry(RegionIdx_t region_id) {
324 return _table->delete_entry(region_id);
325 }
326
327 void SparsePRT::clear() {
328 // If the entry table is not at initial capacity, just create a new one.
329 if (_table->capacity() != InitialCapacity) {
330 delete _table;
331 _table = new RSHashTable(InitialCapacity);
332 } else {
333 _table->clear();
334 }
335 }
336
337 void SparsePRT::expand() {
338 RSHashTable* last = _table;
339 _table = new RSHashTable(last->capacity() * 2);
340 for (size_t i = 0; i < last->num_entries(); i++) {
341 SparsePRTEntry* e = last->entry((int)i);
342 if (e->valid_entry()) {
343 _table->add_entry(e);
344 }
345 }
346 delete last;
347 }