1 /*
2 * Copyright (c) 2001, 2015, 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/heapRegionRemSet.hpp"
28 #include "gc/g1/sparsePRT.hpp"
29 #include "gc/shared/cardTableModRefBS.hpp"
30 #include "gc/shared/space.inline.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "runtime/atomic.inline.hpp"
33 #include "runtime/mutexLocker.hpp"
34
35 #define SPARSE_PRT_VERBOSE 0
36
37 void SparsePRTEntry::init(RegionIdx_t region_ind) {
38 _region_ind = region_ind;
39 _next_index = NullEntry;
40
41 for (int i = 0; i < cards_num(); i++) {
42 _cards[i] = NullEntry;
43 }
44 }
45
46 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
47 for (int i = 0; i < cards_num(); i++) {
48 if (_cards[i] == card_index) return true;
49 }
50 return false;
51 }
52
53 int SparsePRTEntry::num_valid_cards() const {
54 int sum = 0;
55 for (int i = 0; i < cards_num(); i++) {
56 sum += (_cards[i] != NullEntry);
57 }
58 return sum;
59 }
60
61 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
62 for (int i = 0; i < cards_num(); i++) {
63 CardIdx_t c = _cards[i];
64 if (c == card_index) return found;
65 if (c == NullEntry) { _cards[i] = card_index; return added; }
66 }
67 // Otherwise, we're full.
68 return overflow;
69 }
70
71 void SparsePRTEntry::copy_cards(CardIdx_t* cards) const {
72 memcpy(cards, _cards, cards_num() * sizeof(CardIdx_t));
73 }
74
75 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
76 copy_cards(&e->_cards[0]);
77 }
78
79 // ----------------------------------------------------------------------
80
81 RSHashTable::RSHashTable(size_t capacity) :
82 _capacity(capacity), _capacity_mask(capacity-1),
83 _occupied_entries(0), _occupied_cards(0),
84 _entries((SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, SparsePRTEntry::size() * capacity, mtGC)),
85 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)),
86 _free_list(NullEntry), _free_region(0)
87 {
88 clear();
89 }
90
91 RSHashTable::~RSHashTable() {
92 if (_entries != NULL) {
93 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries);
94 _entries = NULL;
95 }
96 if (_buckets != NULL) {
97 FREE_C_HEAP_ARRAY(int, _buckets);
98 _buckets = NULL;
99 }
100 }
101
102 void RSHashTable::clear() {
103 _occupied_entries = 0;
104 _occupied_cards = 0;
105 guarantee(_entries != NULL, "INV");
106 guarantee(_buckets != NULL, "INV");
107
108 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
109 "_capacity too large");
110
111 // This will put -1 == NullEntry in the key field of all entries.
112 memset(_entries, NullEntry, _capacity * SparsePRTEntry::size());
113 memset(_buckets, NullEntry, _capacity * sizeof(int));
114 _free_list = NullEntry;
115 _free_region = 0;
116 }
117
118 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
119 SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
120 assert(e != NULL && e->r_ind() == region_ind,
121 "Postcondition of call above.");
122 SparsePRTEntry::AddCardResult res = e->add_card(card_index);
123 if (res == SparsePRTEntry::added) _occupied_cards++;
124 #if SPARSE_PRT_VERBOSE
125 gclog_or_tty->print_cr(" after add_card[%d]: valid-cards = %d.",
126 pointer_delta(e, _entries, SparsePRTEntry::size()),
127 e->num_valid_cards());
128 #endif
129 assert(e->num_valid_cards() > 0, "Postcondition");
130 return res != SparsePRTEntry::overflow;
131 }
132
133 bool RSHashTable::get_cards(RegionIdx_t region_ind, CardIdx_t* cards) {
134 SparsePRTEntry* entry = get_entry(region_ind);
135 if (entry == NULL) {
136 return false;
137 }
138 // Otherwise...
139 entry->copy_cards(cards);
140 return true;
141 }
142
143 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const {
144 int ind = (int) (region_ind & capacity_mask());
145 int cur_ind = _buckets[ind];
146 SparsePRTEntry* cur;
147 while (cur_ind != NullEntry &&
148 (cur = entry(cur_ind))->r_ind() != region_ind) {
149 cur_ind = cur->next_index();
150 }
151
152 if (cur_ind == NullEntry) return NULL;
153 // Otherwise...
154 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
155 assert(cur->num_valid_cards() > 0, "Inv");
156 return cur;
157 }
158
159 bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
160 int ind = (int) (region_ind & capacity_mask());
161 int* prev_loc = &_buckets[ind];
162 int cur_ind = *prev_loc;
163 SparsePRTEntry* cur;
164 while (cur_ind != NullEntry &&
165 (cur = entry(cur_ind))->r_ind() != region_ind) {
166 prev_loc = cur->next_index_addr();
167 cur_ind = *prev_loc;
168 }
169
170 if (cur_ind == NullEntry) return false;
171 // Otherwise, splice out "cur".
172 *prev_loc = cur->next_index();
173 _occupied_cards -= cur->num_valid_cards();
174 free_entry(cur_ind);
175 _occupied_entries--;
176 return true;
177 }
178
179 SparsePRTEntry*
180 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
181 SparsePRTEntry* res = get_entry(region_ind);
182 if (res == NULL) {
183 int new_ind = alloc_entry();
184 assert(0 <= new_ind && (size_t)new_ind < capacity(), "There should be room.");
185 res = entry(new_ind);
186 res->init(region_ind);
187 // Insert at front.
188 int ind = (int) (region_ind & capacity_mask());
189 res->set_next_index(_buckets[ind]);
190 _buckets[ind] = new_ind;
191 _occupied_entries++;
192 }
193 return res;
194 }
195
196 int RSHashTable::alloc_entry() {
197 int res;
198 if (_free_list != NullEntry) {
199 res = _free_list;
200 _free_list = entry(res)->next_index();
201 return res;
202 } else if ((size_t) _free_region+1 < capacity()) {
203 res = _free_region;
204 _free_region++;
205 return res;
206 } else {
207 return NullEntry;
208 }
209 }
210
211 void RSHashTable::free_entry(int fi) {
212 entry(fi)->set_next_index(_free_list);
213 _free_list = fi;
214 }
215
216 void RSHashTable::add_entry(SparsePRTEntry* e) {
217 assert(e->num_valid_cards() > 0, "Precondition.");
218 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
219 e->copy_cards(e2);
220 _occupied_cards += e2->num_valid_cards();
221 assert(e2->num_valid_cards() > 0, "Postcondition.");
222 }
223
224 CardIdx_t RSHashTableIter::find_first_card_in_list() {
225 CardIdx_t res;
226 while (_bl_ind != RSHashTable::NullEntry) {
227 res = _rsht->entry(_bl_ind)->card(0);
228 if (res != SparsePRTEntry::NullEntry) {
229 return res;
230 } else {
231 _bl_ind = _rsht->entry(_bl_ind)->next_index();
232 }
233 }
234 // Otherwise, none found:
235 return SparsePRTEntry::NullEntry;
236 }
237
238 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) {
239 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci;
240 }
241
242 bool RSHashTableIter::has_next(size_t& card_index) {
243 _card_ind++;
244 CardIdx_t ci;
245 if (_card_ind < SparsePRTEntry::cards_num() &&
246 ((ci = _rsht->entry(_bl_ind)->card(_card_ind)) !=
247 SparsePRTEntry::NullEntry)) {
248 card_index = compute_card_ind(ci);
249 return true;
250 }
251 // Otherwise, must find the next valid entry.
252 _card_ind = 0;
253
254 if (_bl_ind != RSHashTable::NullEntry) {
255 _bl_ind = _rsht->entry(_bl_ind)->next_index();
256 ci = find_first_card_in_list();
257 if (ci != SparsePRTEntry::NullEntry) {
258 card_index = compute_card_ind(ci);
259 return true;
260 }
261 }
262 // If we didn't return above, must go to the next non-null table index.
263 _tbl_ind++;
264 while ((size_t)_tbl_ind < _rsht->capacity()) {
265 _bl_ind = _rsht->_buckets[_tbl_ind];
266 ci = find_first_card_in_list();
267 if (ci != SparsePRTEntry::NullEntry) {
268 card_index = compute_card_ind(ci);
269 return true;
270 }
271 // Otherwise, try next entry.
272 _tbl_ind++;
273 }
274 // Otherwise, there were no entry.
275 return false;
276 }
277
278 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
279 SparsePRTEntry* e = get_entry(region_index);
280 return (e != NULL && e->contains_card(card_index));
281 }
282
283 size_t RSHashTable::mem_size() const {
284 return sizeof(RSHashTable) +
285 capacity() * (SparsePRTEntry::size() + sizeof(int));
286 }
287
288 // ----------------------------------------------------------------------
289
290 SparsePRT* SparsePRT::_head_expanded_list = NULL;
291
292 void SparsePRT::add_to_expanded_list(SparsePRT* sprt) {
293 // We could expand multiple times in a pause -- only put on list once.
294 if (sprt->expanded()) return;
295 sprt->set_expanded(true);
296 SparsePRT* hd = _head_expanded_list;
297 while (true) {
298 sprt->_next_expanded = hd;
299 SparsePRT* res =
300 (SparsePRT*)
301 Atomic::cmpxchg_ptr(sprt, &_head_expanded_list, hd);
302 if (res == hd) return;
303 else hd = res;
304 }
305 }
306
307
308 SparsePRT* SparsePRT::get_from_expanded_list() {
309 SparsePRT* hd = _head_expanded_list;
310 while (hd != NULL) {
311 SparsePRT* next = hd->next_expanded();
312 SparsePRT* res =
313 (SparsePRT*)
314 Atomic::cmpxchg_ptr(next, &_head_expanded_list, hd);
315 if (res == hd) {
316 hd->set_next_expanded(NULL);
317 return hd;
318 } else {
319 hd = res;
320 }
321 }
322 return NULL;
323 }
324
325 void SparsePRT::reset_for_cleanup_tasks() {
326 _head_expanded_list = NULL;
327 }
328
329 void SparsePRT::do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task) {
330 if (should_be_on_expanded_list()) {
331 sprt_cleanup_task->add(this);
332 }
333 }
334
335 void SparsePRT::finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task) {
336 assert(ParGCRareEvent_lock->owned_by_self(), "pre-condition");
337 SparsePRT* head = sprt_cleanup_task->head();
338 SparsePRT* tail = sprt_cleanup_task->tail();
339 if (head != NULL) {
340 assert(tail != NULL, "if head is not NULL, so should tail");
341
342 tail->set_next_expanded(_head_expanded_list);
343 _head_expanded_list = head;
344 } else {
345 assert(tail == NULL, "if head is NULL, so should tail");
346 }
347 }
348
349 bool SparsePRT::should_be_on_expanded_list() {
350 if (_expanded) {
351 assert(_cur != _next, "if _expanded is true, cur should be != _next");
352 } else {
353 assert(_cur == _next, "if _expanded is false, cur should be == _next");
354 }
355 return expanded();
356 }
357
358 void SparsePRT::cleanup_all() {
359 // First clean up all expanded tables so they agree on next and cur.
360 SparsePRT* sprt = get_from_expanded_list();
361 while (sprt != NULL) {
362 sprt->cleanup();
363 sprt = get_from_expanded_list();
364 }
365 }
366
367
368 SparsePRT::SparsePRT(HeapRegion* hr) :
369 _hr(hr), _expanded(false), _next_expanded(NULL)
370 {
371 _cur = new RSHashTable(InitialCapacity);
372 _next = _cur;
373 }
374
375
376 SparsePRT::~SparsePRT() {
377 assert(_next != NULL && _cur != NULL, "Inv");
378 if (_cur != _next) { delete _cur; }
379 delete _next;
380 }
381
382
383 size_t SparsePRT::mem_size() const {
384 // We ignore "_cur" here, because it either = _next, or else it is
385 // on the deleted list.
386 return sizeof(SparsePRT) + _next->mem_size();
387 }
388
389 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
390 #if SPARSE_PRT_VERBOSE
391 gclog_or_tty->print_cr(" Adding card %d from region %d to region %u sparse.",
392 card_index, region_id, _hr->hrm_index());
393 #endif
394 if (_next->occupied_entries() * 2 > _next->capacity()) {
395 expand();
396 }
397 return _next->add_card(region_id, card_index);
398 }
399
400 bool SparsePRT::get_cards(RegionIdx_t region_id, CardIdx_t* cards) {
401 return _next->get_cards(region_id, cards);
402 }
403
404 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
405 return _next->get_entry(region_id);
406 }
407
408 bool SparsePRT::delete_entry(RegionIdx_t region_id) {
409 return _next->delete_entry(region_id);
410 }
411
412 void SparsePRT::clear() {
413 // If they differ, _next is bigger then cur, so next has no chance of
414 // being the initial size.
415 if (_next != _cur) {
416 delete _next;
417 }
418
419 if (_cur->capacity() != InitialCapacity) {
420 delete _cur;
421 _cur = new RSHashTable(InitialCapacity);
422 } else {
423 _cur->clear();
424 }
425 _next = _cur;
426 _expanded = false;
427 }
428
429 void SparsePRT::cleanup() {
430 // Make sure that the current and next tables agree.
431 if (_cur != _next) {
432 delete _cur;
433 }
434 _cur = _next;
435 set_expanded(false);
436 }
437
438 void SparsePRT::expand() {
439 RSHashTable* last = _next;
440 _next = new RSHashTable(last->capacity() * 2);
441
442 #if SPARSE_PRT_VERBOSE
443 gclog_or_tty->print_cr(" Expanded sparse table for %u to %d.",
444 _hr->hrm_index(), _next->capacity());
445 #endif
446 for (size_t i = 0; i < last->capacity(); i++) {
447 SparsePRTEntry* e = last->entry((int)i);
448 if (e->valid_entry()) {
449 #if SPARSE_PRT_VERBOSE
450 gclog_or_tty->print_cr(" During expansion, transferred entry for %d.",
451 e->r_ind());
452 #endif
453 _next->add_entry(e);
454 }
455 }
456 if (last != _cur) {
457 delete last;
458 }
459 add_to_expanded_list(this);
460 }
461
462 void SparsePRTCleanupTask::add(SparsePRT* sprt) {
463 assert(sprt->should_be_on_expanded_list(), "pre-condition");
464
465 sprt->set_next_expanded(NULL);
466 if (_tail != NULL) {
467 _tail->set_next_expanded(sprt);
468 } else {
469 _head = sprt;
470 }
471 _tail = sprt;
472 }