Tue, 13 Apr 2010 13:52:10 -0700
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_sparsePRT.cpp.incl"
28 #define SPARSE_PRT_VERBOSE 0
30 #define UNROLL_CARD_LOOPS 1
32 void SparsePRT::init_iterator(SparsePRTIter* sprt_iter) {
33 sprt_iter->init(this);
34 }
36 void SparsePRTEntry::init(RegionIdx_t region_ind) {
37 _region_ind = region_ind;
38 _next_index = NullEntry;
40 #if UNROLL_CARD_LOOPS
41 assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
42 for (int i = 0; i < cards_num(); i += UnrollFactor) {
43 _cards[i] = NullEntry;
44 _cards[i + 1] = NullEntry;
45 _cards[i + 2] = NullEntry;
46 _cards[i + 3] = NullEntry;
47 }
48 #else
49 for (int i = 0; i < cards_num(); i++)
50 _cards[i] = NullEntry;
51 #endif
52 }
54 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const {
55 #if UNROLL_CARD_LOOPS
56 assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
57 for (int i = 0; i < cards_num(); i += UnrollFactor) {
58 if (_cards[i] == card_index ||
59 _cards[i + 1] == card_index ||
60 _cards[i + 2] == card_index ||
61 _cards[i + 3] == card_index) return true;
62 }
63 #else
64 for (int i = 0; i < cards_num(); i++) {
65 if (_cards[i] == card_index) return true;
66 }
67 #endif
68 // Otherwise, we're full.
69 return false;
70 }
72 int SparsePRTEntry::num_valid_cards() const {
73 int sum = 0;
74 #if UNROLL_CARD_LOOPS
75 assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
76 for (int i = 0; i < cards_num(); i += UnrollFactor) {
77 sum += (_cards[i] != NullEntry);
78 sum += (_cards[i + 1] != NullEntry);
79 sum += (_cards[i + 2] != NullEntry);
80 sum += (_cards[i + 3] != NullEntry);
81 }
82 #else
83 for (int i = 0; i < cards_num(); i++) {
84 sum += (_cards[i] != NullEntry);
85 }
86 #endif
87 // Otherwise, we're full.
88 return sum;
89 }
91 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) {
92 #if UNROLL_CARD_LOOPS
93 assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
94 CardIdx_t c;
95 for (int i = 0; i < cards_num(); i += UnrollFactor) {
96 c = _cards[i];
97 if (c == card_index) return found;
98 if (c == NullEntry) { _cards[i] = card_index; return added; }
99 c = _cards[i + 1];
100 if (c == card_index) return found;
101 if (c == NullEntry) { _cards[i + 1] = card_index; return added; }
102 c = _cards[i + 2];
103 if (c == card_index) return found;
104 if (c == NullEntry) { _cards[i + 2] = card_index; return added; }
105 c = _cards[i + 3];
106 if (c == card_index) return found;
107 if (c == NullEntry) { _cards[i + 3] = card_index; return added; }
108 }
109 #else
110 for (int i = 0; i < cards_num(); i++) {
111 CardIdx_t c = _cards[i];
112 if (c == card_index) return found;
113 if (c == NullEntry) { _cards[i] = card_index; return added; }
114 }
115 #endif
116 // Otherwise, we're full.
117 return overflow;
118 }
120 void SparsePRTEntry::copy_cards(CardIdx_t* cards) const {
121 #if UNROLL_CARD_LOOPS
122 assert((cards_num() & (UnrollFactor - 1)) == 0, "Invalid number of cards in the entry");
123 for (int i = 0; i < cards_num(); i += UnrollFactor) {
124 cards[i] = _cards[i];
125 cards[i + 1] = _cards[i + 1];
126 cards[i + 2] = _cards[i + 2];
127 cards[i + 3] = _cards[i + 3];
128 }
129 #else
130 for (int i = 0; i < cards_num(); i++) {
131 cards[i] = _cards[i];
132 }
133 #endif
134 }
136 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const {
137 copy_cards(&e->_cards[0]);
138 }
140 // ----------------------------------------------------------------------
142 RSHashTable::RSHashTable(size_t capacity) :
143 _capacity(capacity), _capacity_mask(capacity-1),
144 _occupied_entries(0), _occupied_cards(0),
145 _entries((SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, SparsePRTEntry::size() * capacity)),
146 _buckets(NEW_C_HEAP_ARRAY(int, capacity)),
147 _free_list(NullEntry), _free_region(0)
148 {
149 clear();
150 }
152 RSHashTable::~RSHashTable() {
153 if (_entries != NULL) {
154 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries);
155 _entries = NULL;
156 }
157 if (_buckets != NULL) {
158 FREE_C_HEAP_ARRAY(int, _buckets);
159 _buckets = NULL;
160 }
161 }
163 void RSHashTable::clear() {
164 _occupied_entries = 0;
165 _occupied_cards = 0;
166 guarantee(_entries != NULL, "INV");
167 guarantee(_buckets != NULL, "INV");
169 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1,
170 "_capacity too large");
172 // This will put -1 == NullEntry in the key field of all entries.
173 memset(_entries, NullEntry, _capacity * SparsePRTEntry::size());
174 memset(_buckets, NullEntry, _capacity * sizeof(int));
175 _free_list = NullEntry;
176 _free_region = 0;
177 }
179 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
180 SparsePRTEntry* e = entry_for_region_ind_create(region_ind);
181 assert(e != NULL && e->r_ind() == region_ind,
182 "Postcondition of call above.");
183 SparsePRTEntry::AddCardResult res = e->add_card(card_index);
184 if (res == SparsePRTEntry::added) _occupied_cards++;
185 #if SPARSE_PRT_VERBOSE
186 gclog_or_tty->print_cr(" after add_card[%d]: valid-cards = %d.",
187 pointer_delta(e, _entries, SparsePRTEntry::size()),
188 e->num_valid_cards());
189 #endif
190 assert(e->num_valid_cards() > 0, "Postcondition");
191 return res != SparsePRTEntry::overflow;
192 }
194 bool RSHashTable::get_cards(RegionIdx_t region_ind, CardIdx_t* cards) {
195 int ind = (int) (region_ind & capacity_mask());
196 int cur_ind = _buckets[ind];
197 SparsePRTEntry* cur;
198 while (cur_ind != NullEntry &&
199 (cur = entry(cur_ind))->r_ind() != region_ind) {
200 cur_ind = cur->next_index();
201 }
203 if (cur_ind == NullEntry) return false;
204 // Otherwise...
205 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
206 assert(cur->num_valid_cards() > 0, "Inv");
207 cur->copy_cards(cards);
208 return true;
209 }
211 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) {
212 int ind = (int) (region_ind & capacity_mask());
213 int cur_ind = _buckets[ind];
214 SparsePRTEntry* cur;
215 while (cur_ind != NullEntry &&
216 (cur = entry(cur_ind))->r_ind() != region_ind) {
217 cur_ind = cur->next_index();
218 }
220 if (cur_ind == NullEntry) return NULL;
221 // Otherwise...
222 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
223 assert(cur->num_valid_cards() > 0, "Inv");
224 return cur;
225 }
227 bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
228 int ind = (int) (region_ind & capacity_mask());
229 int* prev_loc = &_buckets[ind];
230 int cur_ind = *prev_loc;
231 SparsePRTEntry* cur;
232 while (cur_ind != NullEntry &&
233 (cur = entry(cur_ind))->r_ind() != region_ind) {
234 prev_loc = cur->next_index_addr();
235 cur_ind = *prev_loc;
236 }
238 if (cur_ind == NullEntry) return false;
239 // Otherwise, splice out "cur".
240 *prev_loc = cur->next_index();
241 _occupied_cards -= cur->num_valid_cards();
242 free_entry(cur_ind);
243 _occupied_entries--;
244 return true;
245 }
247 SparsePRTEntry*
248 RSHashTable::entry_for_region_ind(RegionIdx_t region_ind) const {
249 assert(occupied_entries() < capacity(), "Precondition");
250 int ind = (int) (region_ind & capacity_mask());
251 int cur_ind = _buckets[ind];
252 SparsePRTEntry* cur;
253 while (cur_ind != NullEntry &&
254 (cur = entry(cur_ind))->r_ind() != region_ind) {
255 cur_ind = cur->next_index();
256 }
258 if (cur_ind != NullEntry) {
259 assert(cur->r_ind() == region_ind, "Loop postcondition + test");
260 return cur;
261 } else {
262 return NULL;
263 }
264 }
266 SparsePRTEntry*
267 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
268 SparsePRTEntry* res = entry_for_region_ind(region_ind);
269 if (res == NULL) {
270 int new_ind = alloc_entry();
271 assert(0 <= new_ind && (size_t)new_ind < capacity(), "There should be room.");
272 res = entry(new_ind);
273 res->init(region_ind);
274 // Insert at front.
275 int ind = (int) (region_ind & capacity_mask());
276 res->set_next_index(_buckets[ind]);
277 _buckets[ind] = new_ind;
278 _occupied_entries++;
279 }
280 return res;
281 }
283 int RSHashTable::alloc_entry() {
284 int res;
285 if (_free_list != NullEntry) {
286 res = _free_list;
287 _free_list = entry(res)->next_index();
288 return res;
289 } else if ((size_t) _free_region+1 < capacity()) {
290 res = _free_region;
291 _free_region++;
292 return res;
293 } else {
294 return NullEntry;
295 }
296 }
298 void RSHashTable::free_entry(int fi) {
299 entry(fi)->set_next_index(_free_list);
300 _free_list = fi;
301 }
303 void RSHashTable::add_entry(SparsePRTEntry* e) {
304 assert(e->num_valid_cards() > 0, "Precondition.");
305 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind());
306 e->copy_cards(e2);
307 _occupied_cards += e2->num_valid_cards();
308 assert(e2->num_valid_cards() > 0, "Postcondition.");
309 }
311 CardIdx_t /* RSHashTable:: */ RSHashTableIter::find_first_card_in_list() {
312 CardIdx_t res;
313 while (_bl_ind != RSHashTable::NullEntry) {
314 res = _rsht->entry(_bl_ind)->card(0);
315 if (res != SparsePRTEntry::NullEntry) {
316 return res;
317 } else {
318 _bl_ind = _rsht->entry(_bl_ind)->next_index();
319 }
320 }
321 // Otherwise, none found:
322 return SparsePRTEntry::NullEntry;
323 }
325 size_t /* RSHashTable:: */ RSHashTableIter::compute_card_ind(CardIdx_t ci) {
326 return
327 _heap_bot_card_ind
328 + (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion)
329 + ci;
330 }
332 bool /* RSHashTable:: */ RSHashTableIter::has_next(size_t& card_index) {
333 _card_ind++;
334 CardIdx_t ci;
335 if (_card_ind < SparsePRTEntry::cards_num() &&
336 ((ci = _rsht->entry(_bl_ind)->card(_card_ind)) !=
337 SparsePRTEntry::NullEntry)) {
338 card_index = compute_card_ind(ci);
339 return true;
340 }
341 // Otherwise, must find the next valid entry.
342 _card_ind = 0;
344 if (_bl_ind != RSHashTable::NullEntry) {
345 _bl_ind = _rsht->entry(_bl_ind)->next_index();
346 ci = find_first_card_in_list();
347 if (ci != SparsePRTEntry::NullEntry) {
348 card_index = compute_card_ind(ci);
349 return true;
350 }
351 }
352 // If we didn't return above, must go to the next non-null table index.
353 _tbl_ind++;
354 while ((size_t)_tbl_ind < _rsht->capacity()) {
355 _bl_ind = _rsht->_buckets[_tbl_ind];
356 ci = find_first_card_in_list();
357 if (ci != SparsePRTEntry::NullEntry) {
358 card_index = compute_card_ind(ci);
359 return true;
360 }
361 // Otherwise, try next entry.
362 _tbl_ind++;
363 }
364 // Otherwise, there were no entry.
365 return false;
366 }
368 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
369 SparsePRTEntry* e = entry_for_region_ind(region_index);
370 return (e != NULL && e->contains_card(card_index));
371 }
373 size_t RSHashTable::mem_size() const {
374 return sizeof(this) +
375 capacity() * (SparsePRTEntry::size() + sizeof(int));
376 }
378 // ----------------------------------------------------------------------
380 SparsePRT* SparsePRT::_head_expanded_list = NULL;
382 void SparsePRT::add_to_expanded_list(SparsePRT* sprt) {
383 // We could expand multiple times in a pause -- only put on list once.
384 if (sprt->expanded()) return;
385 sprt->set_expanded(true);
386 SparsePRT* hd = _head_expanded_list;
387 while (true) {
388 sprt->_next_expanded = hd;
389 SparsePRT* res =
390 (SparsePRT*)
391 Atomic::cmpxchg_ptr(sprt, &_head_expanded_list, hd);
392 if (res == hd) return;
393 else hd = res;
394 }
395 }
398 SparsePRT* SparsePRT::get_from_expanded_list() {
399 SparsePRT* hd = _head_expanded_list;
400 while (hd != NULL) {
401 SparsePRT* next = hd->next_expanded();
402 SparsePRT* res =
403 (SparsePRT*)
404 Atomic::cmpxchg_ptr(next, &_head_expanded_list, hd);
405 if (res == hd) {
406 hd->set_next_expanded(NULL);
407 return hd;
408 } else {
409 hd = res;
410 }
411 }
412 return NULL;
413 }
416 void SparsePRT::cleanup_all() {
417 // First clean up all expanded tables so they agree on next and cur.
418 SparsePRT* sprt = get_from_expanded_list();
419 while (sprt != NULL) {
420 sprt->cleanup();
421 sprt = get_from_expanded_list();
422 }
423 }
426 SparsePRT::SparsePRT(HeapRegion* hr) :
427 _expanded(false), _next_expanded(NULL)
428 {
429 _cur = new RSHashTable(InitialCapacity);
430 _next = _cur;
431 }
434 SparsePRT::~SparsePRT() {
435 assert(_next != NULL && _cur != NULL, "Inv");
436 if (_cur != _next) { delete _cur; }
437 delete _next;
438 }
441 size_t SparsePRT::mem_size() const {
442 // We ignore "_cur" here, because it either = _next, or else it is
443 // on the deleted list.
444 return sizeof(this) + _next->mem_size();
445 }
447 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) {
448 #if SPARSE_PRT_VERBOSE
449 gclog_or_tty->print_cr(" Adding card %d from region %d to region %d sparse.",
450 card_index, region_id, _hr->hrs_index());
451 #endif
452 if (_next->occupied_entries() * 2 > _next->capacity()) {
453 expand();
454 }
455 return _next->add_card(region_id, card_index);
456 }
458 bool SparsePRT::get_cards(RegionIdx_t region_id, CardIdx_t* cards) {
459 return _next->get_cards(region_id, cards);
460 }
462 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) {
463 return _next->get_entry(region_id);
464 }
466 bool SparsePRT::delete_entry(RegionIdx_t region_id) {
467 return _next->delete_entry(region_id);
468 }
470 void SparsePRT::clear() {
471 // If they differ, _next is bigger then cur, so next has no chance of
472 // being the initial size.
473 if (_next != _cur) {
474 delete _next;
475 }
477 if (_cur->capacity() != InitialCapacity) {
478 delete _cur;
479 _cur = new RSHashTable(InitialCapacity);
480 } else {
481 _cur->clear();
482 }
483 _next = _cur;
484 }
486 void SparsePRT::cleanup() {
487 // Make sure that the current and next tables agree.
488 if (_cur != _next) {
489 delete _cur;
490 }
491 _cur = _next;
492 set_expanded(false);
493 }
495 void SparsePRT::expand() {
496 RSHashTable* last = _next;
497 _next = new RSHashTable(last->capacity() * 2);
499 #if SPARSE_PRT_VERBOSE
500 gclog_or_tty->print_cr(" Expanded sparse table for %d to %d.",
501 _hr->hrs_index(), _next->capacity());
502 #endif
503 for (size_t i = 0; i < last->capacity(); i++) {
504 SparsePRTEntry* e = last->entry((int)i);
505 if (e->valid_entry()) {
506 #if SPARSE_PRT_VERBOSE
507 gclog_or_tty->print_cr(" During expansion, transferred entry for %d.",
508 e->r_ind());
509 #endif
510 _next->add_entry(e);
511 }
512 }
513 if (last != _cur) {
514 delete last;
515 }
516 add_to_expanded_list(this);
517 }