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/atomic.hpp"
34 #include "runtime/mutexLocker.hpp"
35
36 // Check that the size of the SparsePRTEntry is evenly divisible by the maximum
37 // member type to avoid SIGBUS when accessing them.
38 STATIC_ASSERT(sizeof(SparsePRTEntry) % sizeof(int) == 0);
39
40 void SparsePRTEntry::init(RegionIdx_t region_ind) {
41 // Check that the card array element type can represent all cards in the region.
42 // Choose a large SparsePRTEntry::card_elem_t (e.g. CardIdx_t) if required.
43 assert(((size_t)1 << (sizeof(SparsePRTEntry::card_elem_t) * BitsPerByte)) *
44 G1CardTable::card_size >= HeapRegionBounds::max_size(), "precondition");
45 assert(G1RSetSparseRegionEntries > 0, "precondition");
46 _region_ind = region_ind;
47 _next_index = RSHashTable::NullEntry;
48 _next_null = 0;
49 }
50
51 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
52 for (int i = 0; i < num_valid_cards(); i++) {
53 if (card(i) == card_index) {
54 return true;
55 }
56 }
57 return false;
58 }
59
60 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
61 for (int i = 0; i < num_valid_cards(); i++) {
62 if (card(i) == card_index) {
63 return found;
64 }
65 }
66 if (num_valid_cards() < cards_num() - 1) {
67 _cards[_next_null] = (card_elem_t)card_index;
68 _next_null++;
69 return added;
70 }
71 // Otherwise, we're full.
72 return overflow;
73 }
74
75 void SparsePRTEntry::copy_cards(card_elem_t* cards) const {
76 memcpy(cards, _cards, cards_num() * sizeof(card_elem_t));
77 }
78
79 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
80 copy_cards(e->_cards);
81 assert(_next_null >= 0, "invariant");
82 assert(_next_null <= cards_num(), "invariant");
83 e->_next_null = _next_null;
84 }
85
86 // ----------------------------------------------------------------------
87
88 float RSHashTable::TableOccupancyFactor = 0.5f;
89
90 RSHashTable::RSHashTable(size_t capacity) :
91 _num_entries(0),
92 _capacity(capacity),
93 _capacity_mask(capacity-1),
94 _occupied_entries(0),
95 _occupied_cards(0),
96 _entries(NULL),
97 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)),
98 _free_region(0),
99 _free_list(NullEntry)
100 {
101 _num_entries = (capacity * TableOccupancyFactor) + 1;
102 _entries = (SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, _num_entries * SparsePRTEntry::size(), mtGC);
103 clear();
104 }
105
106 RSHashTable::~RSHashTable() {
107 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries);
108 FREE_C_HEAP_ARRAY(int, _buckets);
109 }
110
111 void RSHashTable::clear() {
112 _occupied_entries = 0;
113 _occupied_cards = 0;
114 guarantee(_entries != NULL, "INV");
115 guarantee(_buckets != NULL, "INV");
116
117 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
118 "_capacity too large");
119
120 // This will put -1 == NullEntry in the key field of all entries.
121 memset((void*)_entries, NullEntry, _num_entries * SparsePRTEntry::size());
122 memset((void*)_buckets, NullEntry, _capacity * sizeof(int));
123 _free_list = NullEntry;
124 _free_region = 0;
125 }
126
127 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
128 SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
129 assert(e != NULL && e->r_ind() == region_ind,
130 "Postcondition of call above.");
131 SparsePRTEntry::AddCardResult res = e->add_card(card_index);
132 if (res == SparsePRTEntry::added) _occupied_cards++;
133 assert(e->num_valid_cards() > 0, "Postcondition");
134 return res != SparsePRTEntry::overflow;
135 }
136
137 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const {
138 int ind = (int) (region_ind & capacity_mask());
139 int cur_ind = _buckets[ind];
140 SparsePRTEntry* cur;
141 while (cur_ind != NullEntry &&
142 (cur = entry(cur_ind))->r_ind() != region_ind) {
143 cur_ind = cur->next_index();
144 }
145
146 if (cur_ind == NullEntry) return NULL;
147 // Otherwise...
148 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
149 assert(cur->num_valid_cards() > 0, "Inv");
150 return cur;
151 }
152
153 bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
154 int ind = (int) (region_ind & capacity_mask());
155 int* prev_loc = &_buckets[ind];
156 int cur_ind = *prev_loc;
157 SparsePRTEntry* cur;
158 while (cur_ind != NullEntry &&
159 (cur = entry(cur_ind))->r_ind() != region_ind) {
160 prev_loc = cur->next_index_addr();
161 cur_ind = *prev_loc;
162 }
163
164 if (cur_ind == NullEntry) return false;
165 // Otherwise, splice out "cur".
166 *prev_loc = cur->next_index();
167 _occupied_cards -= cur->num_valid_cards();
168 free_entry(cur_ind);
169 _occupied_entries--;
170 return true;
171 }
172
173 SparsePRTEntry*
174 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
175 SparsePRTEntry* res = get_entry(region_ind);
176 if (res == NULL) {
177 int new_ind = alloc_entry();
178 res = entry(new_ind);
179 res->init(region_ind);
180 // Insert at front.
181 int ind = (int) (region_ind & capacity_mask());
182 res->set_next_index(_buckets[ind]);
183 _buckets[ind] = new_ind;
184 _occupied_entries++;
185 }
186 return res;
187 }
188
189 int RSHashTable::alloc_entry() {
190 int res;
191 if (_free_list != NullEntry) {
192 res = _free_list;
193 _free_list = entry(res)->next_index();
194 return res;
195 } else if ((size_t)_free_region < _num_entries) {
196 res = _free_region;
197 _free_region++;
198 return res;
199 } else {
200 return NullEntry;
201 }
202 }
203
204 void RSHashTable::free_entry(int fi) {
205 entry(fi)->set_next_index(_free_list);
206 _free_list = fi;
207 }
208
209 void RSHashTable::add_entry(SparsePRTEntry* e) {
210 assert(e->num_valid_cards() > 0, "Precondition.");
211 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
212 e->copy_cards(e2);
213 _occupied_cards += e2->num_valid_cards();
214 assert(e2->num_valid_cards() > 0, "Postcondition.");
215 }
216
217 CardIdx_t RSHashTableIter::find_first_card_in_list() {
218 while (_bl_ind != RSHashTable::NullEntry) {
219 SparsePRTEntry* sparse_entry = _rsht->entry(_bl_ind);
220 if (sparse_entry->num_valid_cards() > 0) {
221 return sparse_entry->card(0);
222 } else {
223 _bl_ind = sparse_entry->next_index();
224 }
225 }
226 // Otherwise, none found:
227 return NoCardFound;
228 }
229
230 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) {
231 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci;
232 }
233
234 bool RSHashTableIter::has_next(size_t& card_index) {
235 _card_ind++;
236 if (_bl_ind >= 0) {
237 SparsePRTEntry* e = _rsht->entry(_bl_ind);
238 if (_card_ind < e->num_valid_cards()) {
239 CardIdx_t ci = e->card(_card_ind);
240 card_index = compute_card_ind(ci);
241 return true;
242 }
243 }
244
245 // Otherwise, must find the next valid entry.
246 _card_ind = 0;
247
248 if (_bl_ind != RSHashTable::NullEntry) {
249 _bl_ind = _rsht->entry(_bl_ind)->next_index();
250 CardIdx_t ci = find_first_card_in_list();
251 if (ci != NoCardFound) {
252 card_index = compute_card_ind(ci);
253 return true;
254 }
255 }
256 // If we didn't return above, must go to the next non-null table index.
257 _tbl_ind++;
258 while ((size_t)_tbl_ind < _rsht->capacity()) {
259 _bl_ind = _rsht->_buckets[_tbl_ind];
260 CardIdx_t ci = find_first_card_in_list();
261 if (ci != NoCardFound) {
262 card_index = compute_card_ind(ci);
263 return true;
264 }
265 // Otherwise, try next entry.
266 _tbl_ind++;
267 }
268 // Otherwise, there were no entry.
269 return false;
270 }
271
272 bool RSHashTableBucketIter::has_next(SparsePRTEntry*& entry) {
273 while (_bl_ind == RSHashTable::NullEntry) {
274 if (_tbl_ind == (int)_rsht->capacity() - 1) {
275 return false;
276 }
277 _tbl_ind++;
278 _bl_ind = _rsht->_buckets[_tbl_ind];
279 }
280 entry = _rsht->entry(_bl_ind);
281 _bl_ind = entry->next_index();
282 return true;
283 }
284
285 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
286 SparsePRTEntry* e = get_entry(region_index);
287 return (e != NULL && e->contains_card(card_index));
288 }
289
290 size_t RSHashTable::mem_size() const {
291 return sizeof(RSHashTable) +
292 _num_entries * (SparsePRTEntry::size() + sizeof(int));
293 }
294
295 // ----------------------------------------------------------------------
296
297 SparsePRT::SparsePRT() :
298 _table(new RSHashTable(InitialCapacity)) {
299 }
300
301
302 SparsePRT::~SparsePRT() {
303 delete _table;
304 }
305
306
307 size_t SparsePRT::mem_size() const {
308 // We ignore "_cur" here, because it either = _next, or else it is
309 // on the deleted list.
310 return sizeof(SparsePRT) + _table->mem_size();
311 }
312
313 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
314 if (_table->should_expand()) {
315 expand();
316 }
317 return _table->add_card(region_id, card_index);
318 }
319
320 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
321 return _table->get_entry(region_id);
322 }
323
324 bool SparsePRT::delete_entry(RegionIdx_t region_id) {
325 return _table->delete_entry(region_id);
326 }
327
328 void SparsePRT::clear() {
329 // If the entry table is not at initial capacity, just create a new one.
330 if (_table->capacity() != InitialCapacity) {
331 delete _table;
332 _table = new RSHashTable(InitialCapacity);
333 } else {
334 _table->clear();
335 }
336 }
337
338 void SparsePRT::expand() {
339 RSHashTable* last = _table;
340 _table = new RSHashTable(last->capacity() * 2);
341 for (size_t i = 0; i < last->num_entries(); i++) {
342 SparsePRTEntry* e = last->entry((int)i);
343 if (e->valid_entry()) {
344 _table->add_entry(e);
345 }
346 }
347 delete last;
348 }