1 /*
2 * Copyright (c) 2001, 2014, 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/heapRegion.hpp"
27 #include "gc_implementation/g1/heapRegionRemSet.hpp"
28 #include "gc_implementation/g1/sparsePRT.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/cardTableModRefBS.hpp"
31 #include "memory/space.inline.hpp"
32 #include "runtime/mutexLocker.hpp"
33
34 #define SPARSE_PRT_VERBOSE 0
35
36 void SparsePRTEntry::init(RegionIdx_t region_ind) {
37 _region_ind = region_ind;
38 _next_index = NullEntry;
39
40 for (int i = 0; i < cards_num(); i++) {
41 _cards[i] = NullEntry;
42 }
43 }
44
45 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
46 for (int i = 0; i < cards_num(); i++) {
47 if (_cards[i] == card_index) return true;
48 }
49 return false;
50 }
51
52 int SparsePRTEntry::num_valid_cards() const {
53 int sum = 0;
54 for (int i = 0; i < cards_num(); i++) {
55 sum += (_cards[i] != NullEntry);
56 }
57 return sum;
58 }
59
60 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
61 for (int i = 0; i < cards_num(); i++) {
62 CardIdx_t c = _cards[i];
63 if (c == card_index) return found;
64 if (c == NullEntry) { _cards[i] = card_index; return added; }
65 }
66 // Otherwise, we're full.
67 return overflow;
68 }
69
70 void SparsePRTEntry::copy_cards(CardIdx_t* cards) const {
71 memcpy(cards, _cards, cards_num() * sizeof(CardIdx_t));
72 }
73
74 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
75 copy_cards(&e->_cards[0]);
76 }
77
78 // ----------------------------------------------------------------------
79
80 RSHashTable::RSHashTable(size_t capacity) :
81 _capacity(capacity), _capacity_mask(capacity-1),
82 _occupied_entries(0), _occupied_cards(0),
83 _entries((SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, SparsePRTEntry::size() * capacity, mtGC)),
84 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)),
85 _free_list(NullEntry), _free_region(0)
86 {
87 clear();
88 }
89
90 RSHashTable::~RSHashTable() {
91 if (_entries != NULL) {
92 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries, mtGC);
93 _entries = NULL;
94 }
95 if (_buckets != NULL) {
96 FREE_C_HEAP_ARRAY(int, _buckets, mtGC);
97 _buckets = NULL;
98 }
99 }
100
101 void RSHashTable::clear() {
102 _occupied_entries = 0;
103 _occupied_cards = 0;
104 guarantee(_entries != NULL, "INV");
105 guarantee(_buckets != NULL, "INV");
106
107 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
108 "_capacity too large");
109
110 // This will put -1 == NullEntry in the key field of all entries.
111 memset(_entries, NullEntry, _capacity * SparsePRTEntry::size());
112 memset(_buckets, NullEntry, _capacity * sizeof(int));
113 _free_list = NullEntry;
114 _free_region = 0;
115 }
116
117 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
118 SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
119 assert(e != NULL && e->r_ind() == region_ind,
120 "Postcondition of call above.");
121 SparsePRTEntry::AddCardResult res = e->add_card(card_index);
122 if (res == SparsePRTEntry::added) _occupied_cards++;
123 #if SPARSE_PRT_VERBOSE
124 gclog_or_tty->print_cr(" after add_card[%d]: valid-cards = %d.",
125 pointer_delta(e, _entries, SparsePRTEntry::size()),
126 e->num_valid_cards());
127 #endif
128 assert(e->num_valid_cards() > 0, "Postcondition");
129 return res != SparsePRTEntry::overflow;
130 }
131
132 bool RSHashTable::get_cards(RegionIdx_t region_ind, CardIdx_t* cards) {
133 SparsePRTEntry* entry = get_entry(region_ind);
134 if (entry == NULL) {
135 return false;
136 }
137 // Otherwise...
138 entry->copy_cards(cards);
139 return true;
140 }
141
142 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const {
143 int ind = (int) (region_ind & capacity_mask());
144 int cur_ind = _buckets[ind];
145 SparsePRTEntry* cur;
146 while (cur_ind != NullEntry &&
147 (cur = entry(cur_ind))->r_ind() != region_ind) {
148 cur_ind = cur->next_index();
149 }
150
151 if (cur_ind == NullEntry) return NULL;
152 // Otherwise...
153 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
154 assert(cur->num_valid_cards() > 0, "Inv");
155 return cur;
156 }
157
158 bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
159 int ind = (int) (region_ind & capacity_mask());
160 int* prev_loc = &_buckets[ind];
161 int cur_ind = *prev_loc;
162 SparsePRTEntry* cur;
163 while (cur_ind != NullEntry &&
164 (cur = entry(cur_ind))->r_ind() != region_ind) {
165 prev_loc = cur->next_index_addr();
166 cur_ind = *prev_loc;
167 }
168
169 if (cur_ind == NullEntry) return false;
170 // Otherwise, splice out "cur".
171 *prev_loc = cur->next_index();
172 _occupied_cards -= cur->num_valid_cards();
173 free_entry(cur_ind);
174 _occupied_entries--;
175 return true;
176 }
177
178 SparsePRTEntry*
179 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
180 SparsePRTEntry* res = get_entry(region_ind);
181 if (res == NULL) {
182 int new_ind = alloc_entry();
183 assert(0 <= new_ind && (size_t)new_ind < capacity(), "There should be room.");
184 res = entry(new_ind);
185 res->init(region_ind);
186 // Insert at front.
187 int ind = (int) (region_ind & capacity_mask());
188 res->set_next_index(_buckets[ind]);
189 _buckets[ind] = new_ind;
190 _occupied_entries++;
191 }
192 return res;
193 }
194
195 int RSHashTable::alloc_entry() {
196 int res;
197 if (_free_list != NullEntry) {
198 res = _free_list;
199 _free_list = entry(res)->next_index();
200 return res;
201 } else if ((size_t) _free_region+1 < capacity()) {
202 res = _free_region;
203 _free_region++;
204 return res;
205 } else {
206 return NullEntry;
207 }
208 }
209
210 void RSHashTable::free_entry(int fi) {
211 entry(fi)->set_next_index(_free_list);
212 _free_list = fi;
213 }
214
215 void RSHashTable::add_entry(SparsePRTEntry* e) {
216 assert(e->num_valid_cards() > 0, "Precondition.");
217 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
218 e->copy_cards(e2);
219 _occupied_cards += e2->num_valid_cards();
220 assert(e2->num_valid_cards() > 0, "Postcondition.");
221 }
222
223 CardIdx_t RSHashTableIter::find_first_card_in_list() {
224 CardIdx_t res;
225 while (_bl_ind != RSHashTable::NullEntry) {
226 res = _rsht->entry(_bl_ind)->card(0);
227 if (res != SparsePRTEntry::NullEntry) {
228 return res;
229 } else {
230 _bl_ind = _rsht->entry(_bl_ind)->next_index();
231 }
232 }
233 // Otherwise, none found:
234 return SparsePRTEntry::NullEntry;
235 }
236
237 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) {
238 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci;
239 }
240
241 bool RSHashTableIter::has_next(size_t& card_index) {
242 _card_ind++;
243 CardIdx_t ci;
244 if (_card_ind < SparsePRTEntry::cards_num() &&
245 ((ci = _rsht->entry(_bl_ind)->card(_card_ind)) !=
246 SparsePRTEntry::NullEntry)) {
247 card_index = compute_card_ind(ci);
248 return true;
249 }
250 // Otherwise, must find the next valid entry.
251 _card_ind = 0;
252
253 if (_bl_ind != RSHashTable::NullEntry) {
254 _bl_ind = _rsht->entry(_bl_ind)->next_index();
255 ci = find_first_card_in_list();
256 if (ci != SparsePRTEntry::NullEntry) {
257 card_index = compute_card_ind(ci);
258 return true;
259 }
260 }
261 // If we didn't return above, must go to the next non-null table index.
262 _tbl_ind++;
263 while ((size_t)_tbl_ind < _rsht->capacity()) {
264 _bl_ind = _rsht->_buckets[_tbl_ind];
265 ci = find_first_card_in_list();
266 if (ci != SparsePRTEntry::NullEntry) {
267 card_index = compute_card_ind(ci);
268 return true;
269 }
270 // Otherwise, try next entry.
271 _tbl_ind++;
272 }
273 // Otherwise, there were no entry.
274 return false;
275 }
276
277 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
278 SparsePRTEntry* e = get_entry(region_index);
279 return (e != NULL && e->contains_card(card_index));
280 }
281
282 size_t RSHashTable::mem_size() const {
283 return sizeof(RSHashTable) +
284 capacity() * (SparsePRTEntry::size() + sizeof(int));
285 }
286
287 // ----------------------------------------------------------------------
288
289 SparsePRT* SparsePRT::_head_expanded_list = NULL;
290
291 void SparsePRT::add_to_expanded_list(SparsePRT* sprt) {
292 // We could expand multiple times in a pause -- only put on list once.
293 if (sprt->expanded()) return;
294 sprt->set_expanded(true);
295 SparsePRT* hd = _head_expanded_list;
296 while (true) {
297 sprt->_next_expanded = hd;
298 SparsePRT* res =
299 (SparsePRT*)
300 Atomic::cmpxchg_ptr(sprt, &_head_expanded_list, hd);
301 if (res == hd) return;
302 else hd = res;
303 }
304 }
305
306
307 SparsePRT* SparsePRT::get_from_expanded_list() {
308 SparsePRT* hd = _head_expanded_list;
309 while (hd != NULL) {
310 SparsePRT* next = hd->next_expanded();
311 SparsePRT* res =
312 (SparsePRT*)
313 Atomic::cmpxchg_ptr(next, &_head_expanded_list, hd);
314 if (res == hd) {
315 hd->set_next_expanded(NULL);
316 return hd;
317 } else {
318 hd = res;
319 }
320 }
321 return NULL;
322 }
323
324 void SparsePRT::reset_for_cleanup_tasks() {
325 _head_expanded_list = NULL;
326 }
327
328 void SparsePRT::do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task) {
329 if (should_be_on_expanded_list()) {
330 sprt_cleanup_task->add(this);
331 }
332 }
333
334 void SparsePRT::finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task) {
335 assert(ParGCRareEvent_lock->owned_by_self(), "pre-condition");
336 SparsePRT* head = sprt_cleanup_task->head();
337 SparsePRT* tail = sprt_cleanup_task->tail();
338 if (head != NULL) {
339 assert(tail != NULL, "if head is not NULL, so should tail");
340
341 tail->set_next_expanded(_head_expanded_list);
342 _head_expanded_list = head;
343 } else {
344 assert(tail == NULL, "if head is NULL, so should tail");
345 }
346 }
347
348 bool SparsePRT::should_be_on_expanded_list() {
349 if (_expanded) {
350 assert(_cur != _next, "if _expanded is true, cur should be != _next");
351 } else {
352 assert(_cur == _next, "if _expanded is false, cur should be == _next");
353 }
354 return expanded();
355 }
356
357 void SparsePRT::cleanup_all() {
358 // First clean up all expanded tables so they agree on next and cur.
359 SparsePRT* sprt = get_from_expanded_list();
360 while (sprt != NULL) {
361 sprt->cleanup();
362 sprt = get_from_expanded_list();
363 }
364 }
365
366
367 SparsePRT::SparsePRT(HeapRegion* hr) :
368 _hr(hr), _expanded(false), _next_expanded(NULL)
369 {
370 _cur = new RSHashTable(InitialCapacity);
371 _next = _cur;
372 }
373
374
375 SparsePRT::~SparsePRT() {
376 assert(_next != NULL && _cur != NULL, "Inv");
377 if (_cur != _next) { delete _cur; }
378 delete _next;
379 }
380
381
382 size_t SparsePRT::mem_size() const {
383 // We ignore "_cur" here, because it either = _next, or else it is
384 // on the deleted list.
385 return sizeof(SparsePRT) + _next->mem_size();
386 }
387
388 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
389 #if SPARSE_PRT_VERBOSE
390 gclog_or_tty->print_cr(" Adding card %d from region %d to region %u sparse.",
391 card_index, region_id, _hr->hrs_index());
392 #endif
393 if (_next->occupied_entries() * 2 > _next->capacity()) {
394 expand();
395 }
396 return _next->add_card(region_id, card_index);
397 }
398
399 bool SparsePRT::get_cards(RegionIdx_t region_id, CardIdx_t* cards) {
400 return _next->get_cards(region_id, cards);
401 }
402
403 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
404 return _next->get_entry(region_id);
405 }
406
407 bool SparsePRT::delete_entry(RegionIdx_t region_id) {
408 return _next->delete_entry(region_id);
409 }
410
411 void SparsePRT::clear() {
412 // If they differ, _next is bigger then cur, so next has no chance of
413 // being the initial size.
414 if (_next != _cur) {
415 delete _next;
416 }
417
418 if (_cur->capacity() != InitialCapacity) {
419 delete _cur;
420 _cur = new RSHashTable(InitialCapacity);
421 } else {
422 _cur->clear();
423 }
424 _next = _cur;
425 _expanded = false;
426 }
427
428 void SparsePRT::cleanup() {
429 // Make sure that the current and next tables agree.
430 if (_cur != _next) {
431 delete _cur;
432 }
433 _cur = _next;
434 set_expanded(false);
435 }
436
437 void SparsePRT::expand() {
438 RSHashTable* last = _next;
439 _next = new RSHashTable(last->capacity() * 2);
440
441 #if SPARSE_PRT_VERBOSE
442 gclog_or_tty->print_cr(" Expanded sparse table for %u to %d.",
443 _hr->hrs_index(), _next->capacity());
444 #endif
445 for (size_t i = 0; i < last->capacity(); i++) {
446 SparsePRTEntry* e = last->entry((int)i);
447 if (e->valid_entry()) {
448 #if SPARSE_PRT_VERBOSE
449 gclog_or_tty->print_cr(" During expansion, transferred entry for %d.",
450 e->r_ind());
451 #endif
452 _next->add_entry(e);
453 }
454 }
455 if (last != _cur) {
456 delete last;
457 }
458 add_to_expanded_list(this);
459 }
460
461 void SparsePRTCleanupTask::add(SparsePRT* sprt) {
462 assert(sprt->should_be_on_expanded_list(), "pre-condition");
463
464 sprt->set_next_expanded(NULL);
465 if (_tail != NULL) {
466 _tail->set_next_expanded(sprt);
467 } else {
468 _head = sprt;
469 }
470 _tail = sprt;
471 }