1 /*
2 * Copyright (c) 2001, 2012, 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/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/heapRegionRemSet.hpp"
30 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
31 #include "memory/allocation.hpp"
32 #include "memory/space.inline.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "utilities/bitMap.inline.hpp"
35 #include "utilities/globalDefinitions.hpp"
36
37 class PerRegionTable: public CHeapObj<mtGC> {
38 friend class OtherRegionsTable;
39 friend class HeapRegionRemSetIterator;
40
41 HeapRegion* _hr;
42 BitMap _bm;
43 jint _occupied;
44
45 // next pointer for free/allocated 'all' list
46 PerRegionTable* _next;
47
48 // prev pointer for the allocated 'all' list
49 PerRegionTable* _prev;
50
51 // next pointer in collision list
52 PerRegionTable * _collision_list_next;
53
54 // Global free list of PRTs
55 static PerRegionTable* _free_list;
56
57 protected:
58 // We need access in order to union things into the base table.
59 BitMap* bm() { return &_bm; }
60
61 void recount_occupied() {
62 _occupied = (jint) bm()->count_one_bits();
63 }
64
65 PerRegionTable(HeapRegion* hr) :
66 _hr(hr),
67 _occupied(0),
68 _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
69 _collision_list_next(NULL), _next(NULL), _prev(NULL)
70 {}
71
72 void add_card_work(CardIdx_t from_card, bool par) {
73 if (!_bm.at(from_card)) {
74 if (par) {
75 if (_bm.par_at_put(from_card, 1)) {
76 Atomic::inc(&_occupied);
77 }
78 } else {
79 _bm.at_put(from_card, 1);
80 _occupied++;
81 }
82 }
83 }
84
85 void add_reference_work(OopOrNarrowOopStar from, bool par) {
86 // Must make this robust in case "from" is not in "_hr", because of
87 // concurrency.
88
89 if (G1TraceHeapRegionRememberedSet) {
90 gclog_or_tty->print_cr(" PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
91 from,
92 UseCompressedOops
93 ? oopDesc::load_decode_heap_oop((narrowOop*)from)
94 : oopDesc::load_decode_heap_oop((oop*)from));
95 }
96
97 HeapRegion* loc_hr = hr();
98 // If the test below fails, then this table was reused concurrently
99 // with this operation. This is OK, since the old table was coarsened,
100 // and adding a bit to the new table is never incorrect.
101 // If the table used to belong to a continues humongous region and is
102 // now reused for the corresponding start humongous region, we need to
103 // make sure that we detect this. Thus, we call is_in_reserved_raw()
104 // instead of just is_in_reserved() here.
105 if (loc_hr->is_in_reserved_raw(from)) {
106 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
107 CardIdx_t from_card = (CardIdx_t)
108 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
109
110 assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
111 "Must be in range.");
112 add_card_work(from_card, par);
113 }
114 }
115
116 public:
117
118 HeapRegion* hr() const { return _hr; }
119
120 jint occupied() const {
121 // Overkill, but if we ever need it...
122 // guarantee(_occupied == _bm.count_one_bits(), "Check");
123 return _occupied;
124 }
125
126 void init(HeapRegion* hr, bool clear_links_to_all_list) {
127 if (clear_links_to_all_list) {
128 set_next(NULL);
129 set_prev(NULL);
130 }
131 _hr = hr;
132 _collision_list_next = NULL;
133 _occupied = 0;
134 _bm.clear();
135 }
136
137 void add_reference(OopOrNarrowOopStar from) {
138 add_reference_work(from, /*parallel*/ true);
139 }
140
141 void seq_add_reference(OopOrNarrowOopStar from) {
142 add_reference_work(from, /*parallel*/ false);
143 }
144
145 void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
146 HeapWord* hr_bot = hr()->bottom();
147 size_t hr_first_card_index = ctbs->index_for(hr_bot);
148 bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
149 recount_occupied();
150 }
151
152 void add_card(CardIdx_t from_card_index) {
153 add_card_work(from_card_index, /*parallel*/ true);
154 }
155
156 void seq_add_card(CardIdx_t from_card_index) {
157 add_card_work(from_card_index, /*parallel*/ false);
158 }
159
160 // (Destructively) union the bitmap of the current table into the given
161 // bitmap (which is assumed to be of the same size.)
162 void union_bitmap_into(BitMap* bm) {
163 bm->set_union(_bm);
164 }
165
166 // Mem size in bytes.
167 size_t mem_size() const {
168 return sizeof(this) + _bm.size_in_words() * HeapWordSize;
169 }
170
171 // Requires "from" to be in "hr()".
172 bool contains_reference(OopOrNarrowOopStar from) const {
173 assert(hr()->is_in_reserved(from), "Precondition.");
174 size_t card_ind = pointer_delta(from, hr()->bottom(),
175 CardTableModRefBS::card_size);
176 return _bm.at(card_ind);
177 }
178
179 // Bulk-free the PRTs from prt to last, assumes that they are
180 // linked together using their _next field.
181 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
182 while (true) {
183 PerRegionTable* fl = _free_list;
184 last->set_next(fl);
185 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
186 if (res == fl) {
187 return;
188 }
189 }
190 ShouldNotReachHere();
191 }
192
193 static void free(PerRegionTable* prt) {
194 bulk_free(prt, prt);
195 }
196
197 // Returns an initialized PerRegionTable instance.
198 static PerRegionTable* alloc(HeapRegion* hr) {
199 PerRegionTable* fl = _free_list;
200 while (fl != NULL) {
201 PerRegionTable* nxt = fl->next();
202 PerRegionTable* res =
203 (PerRegionTable*)
204 Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
205 if (res == fl) {
206 fl->init(hr, true);
207 return fl;
208 } else {
209 fl = _free_list;
210 }
211 }
212 assert(fl == NULL, "Loop condition.");
213 return new PerRegionTable(hr);
214 }
215
216 PerRegionTable* next() const { return _next; }
217 void set_next(PerRegionTable* next) { _next = next; }
218 PerRegionTable* prev() const { return _prev; }
219 void set_prev(PerRegionTable* prev) { _prev = prev; }
220
221 // Accessor and Modification routines for the pointer for the
222 // singly linked collision list that links the PRTs within the
223 // OtherRegionsTable::_fine_grain_regions hash table.
224 //
225 // It might be useful to also make the collision list doubly linked
226 // to avoid iteration over the collisions list during scrubbing/deletion.
227 // OTOH there might not be many collisions.
228
229 PerRegionTable* collision_list_next() const {
230 return _collision_list_next;
231 }
232
233 void set_collision_list_next(PerRegionTable* next) {
234 _collision_list_next = next;
235 }
236
237 PerRegionTable** collision_list_next_addr() {
238 return &_collision_list_next;
239 }
240
241 static size_t fl_mem_size() {
242 PerRegionTable* cur = _free_list;
243 size_t res = 0;
244 while (cur != NULL) {
245 res += cur->mem_size();
246 cur = cur->next();
247 }
248 return res;
249 }
250
251 static void test_fl_mem_size();
252 };
253
254 PerRegionTable* PerRegionTable::_free_list = NULL;
255
256 size_t OtherRegionsTable::_max_fine_entries = 0;
257 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
258 size_t OtherRegionsTable::_fine_eviction_stride = 0;
259 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
260
261 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr) :
262 _g1h(G1CollectedHeap::heap()),
263 _m(Mutex::leaf, "An OtherRegionsTable lock", true),
264 _hr(hr),
265 _coarse_map(G1CollectedHeap::heap()->max_regions(),
266 false /* in-resource-area */),
267 _fine_grain_regions(NULL),
268 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
269 _n_fine_entries(0), _n_coarse_entries(0),
270 _fine_eviction_start(0),
271 _sparse_table(hr)
272 {
273 typedef PerRegionTable* PerRegionTablePtr;
274
275 if (_max_fine_entries == 0) {
276 assert(_mod_max_fine_entries_mask == 0, "Both or none.");
277 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
278 _max_fine_entries = (size_t)1 << max_entries_log;
279 _mod_max_fine_entries_mask = _max_fine_entries - 1;
280
281 assert(_fine_eviction_sample_size == 0
282 && _fine_eviction_stride == 0, "All init at same time.");
283 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
284 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
285 }
286
287 _fine_grain_regions = new PerRegionTablePtr[_max_fine_entries];
288
289 if (_fine_grain_regions == NULL) {
290 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
291 "Failed to allocate _fine_grain_entries.");
292 }
293
294 for (size_t i = 0; i < _max_fine_entries; i++) {
295 _fine_grain_regions[i] = NULL;
296 }
297 }
298
299 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
300 // We always append to the beginning of the list for convenience;
301 // the order of entries in this list does not matter.
302 if (_first_all_fine_prts != NULL) {
303 assert(_first_all_fine_prts->prev() == NULL, "invariant");
304 _first_all_fine_prts->set_prev(prt);
305 prt->set_next(_first_all_fine_prts);
306 } else {
307 // this is the first element we insert. Adjust the "last" pointer
308 _last_all_fine_prts = prt;
309 assert(prt->next() == NULL, "just checking");
310 }
311 // the new element is always the first element without a predecessor
312 prt->set_prev(NULL);
313 _first_all_fine_prts = prt;
314
315 assert(prt->prev() == NULL, "just checking");
316 assert(_first_all_fine_prts == prt, "just checking");
317 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
318 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
319 "just checking");
320 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
321 "just checking");
322 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
323 "just checking");
324 }
325
326 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
327 if (prt->prev() != NULL) {
328 assert(_first_all_fine_prts != prt, "just checking");
329 prt->prev()->set_next(prt->next());
330 // removing the last element in the list?
331 if (_last_all_fine_prts == prt) {
332 _last_all_fine_prts = prt->prev();
333 }
334 } else {
335 assert(_first_all_fine_prts == prt, "just checking");
336 _first_all_fine_prts = prt->next();
337 // list is empty now?
338 if (_first_all_fine_prts == NULL) {
339 _last_all_fine_prts = NULL;
340 }
341 }
342
343 if (prt->next() != NULL) {
344 prt->next()->set_prev(prt->prev());
345 }
346
347 prt->set_next(NULL);
348 prt->set_prev(NULL);
349
350 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
351 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
352 "just checking");
353 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
354 "just checking");
355 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
356 "just checking");
357 }
358
359 int** OtherRegionsTable::_from_card_cache = NULL;
360 size_t OtherRegionsTable::_from_card_cache_max_regions = 0;
361 size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
362
363 void OtherRegionsTable::init_from_card_cache(size_t max_regions) {
364 _from_card_cache_max_regions = max_regions;
365
366 int n_par_rs = HeapRegionRemSet::num_par_rem_sets();
367 _from_card_cache = NEW_C_HEAP_ARRAY(int*, n_par_rs, mtGC);
368 for (int i = 0; i < n_par_rs; i++) {
369 _from_card_cache[i] = NEW_C_HEAP_ARRAY(int, max_regions, mtGC);
370 for (size_t j = 0; j < max_regions; j++) {
371 _from_card_cache[i][j] = -1; // An invalid value.
372 }
373 }
374 _from_card_cache_mem_size = n_par_rs * max_regions * sizeof(int);
375 }
376
377 void OtherRegionsTable::shrink_from_card_cache(size_t new_n_regs) {
378 for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
379 assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
380 for (size_t j = new_n_regs; j < _from_card_cache_max_regions; j++) {
381 _from_card_cache[i][j] = -1; // An invalid value.
382 }
383 }
384 }
385
386 #ifndef PRODUCT
387 void OtherRegionsTable::print_from_card_cache() {
388 for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
389 for (size_t j = 0; j < _from_card_cache_max_regions; j++) {
390 gclog_or_tty->print_cr("_from_card_cache[%d][%d] = %d.",
391 i, j, _from_card_cache[i][j]);
392 }
393 }
394 }
395 #endif
396
397 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, int tid) {
398 size_t cur_hrs_ind = (size_t) hr()->hrs_index();
399
400 if (G1TraceHeapRegionRememberedSet) {
401 gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
402 from,
403 UseCompressedOops
404 ? oopDesc::load_decode_heap_oop((narrowOop*)from)
405 : oopDesc::load_decode_heap_oop((oop*)from));
406 }
407
408 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
409
410 if (G1TraceHeapRegionRememberedSet) {
411 gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
412 hr()->bottom(), from_card,
413 _from_card_cache[tid][cur_hrs_ind]);
414 }
415
416 if (from_card == _from_card_cache[tid][cur_hrs_ind]) {
417 if (G1TraceHeapRegionRememberedSet) {
418 gclog_or_tty->print_cr(" from-card cache hit.");
419 }
420 assert(contains_reference(from), "We just added it!");
421 return;
422 } else {
423 _from_card_cache[tid][cur_hrs_ind] = from_card;
424 }
425
426 // Note that this may be a continued H region.
427 HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
428 RegionIdx_t from_hrs_ind = (RegionIdx_t) from_hr->hrs_index();
429
430 // If the region is already coarsened, return.
431 if (_coarse_map.at(from_hrs_ind)) {
432 if (G1TraceHeapRegionRememberedSet) {
433 gclog_or_tty->print_cr(" coarse map hit.");
434 }
435 assert(contains_reference(from), "We just added it!");
436 return;
437 }
438
439 // Otherwise find a per-region table to add it to.
440 size_t ind = from_hrs_ind & _mod_max_fine_entries_mask;
441 PerRegionTable* prt = find_region_table(ind, from_hr);
442 if (prt == NULL) {
443 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
444 // Confirm that it's really not there...
445 prt = find_region_table(ind, from_hr);
446 if (prt == NULL) {
447
448 uintptr_t from_hr_bot_card_index =
449 uintptr_t(from_hr->bottom())
450 >> CardTableModRefBS::card_shift;
451 CardIdx_t card_index = from_card - from_hr_bot_card_index;
452 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
453 "Must be in range.");
454 if (G1HRRSUseSparseTable &&
455 _sparse_table.add_card(from_hrs_ind, card_index)) {
456 if (G1RecordHRRSOops) {
457 HeapRegionRemSet::record(hr(), from);
458 if (G1TraceHeapRegionRememberedSet) {
459 gclog_or_tty->print(" Added card " PTR_FORMAT " to region "
460 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
461 align_size_down(uintptr_t(from),
462 CardTableModRefBS::card_size),
463 hr()->bottom(), from);
464 }
465 }
466 if (G1TraceHeapRegionRememberedSet) {
467 gclog_or_tty->print_cr(" added card to sparse table.");
468 }
469 assert(contains_reference_locked(from), "We just added it!");
470 return;
471 } else {
472 if (G1TraceHeapRegionRememberedSet) {
473 gclog_or_tty->print_cr(" [tid %d] sparse table entry "
474 "overflow(f: %d, t: %d)",
475 tid, from_hrs_ind, cur_hrs_ind);
476 }
477 }
478
479 if (_n_fine_entries == _max_fine_entries) {
480 prt = delete_region_table();
481 // There is no need to clear the links to the 'all' list here:
482 // prt will be reused immediately, i.e. remain in the 'all' list.
483 prt->init(from_hr, false /* clear_links_to_all_list */);
484 } else {
485 prt = PerRegionTable::alloc(from_hr);
486 link_to_all(prt);
487 }
488
489 PerRegionTable* first_prt = _fine_grain_regions[ind];
490 prt->set_collision_list_next(first_prt);
491 _fine_grain_regions[ind] = prt;
492 _n_fine_entries++;
493
494 if (G1HRRSUseSparseTable) {
495 // Transfer from sparse to fine-grain.
496 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrs_ind);
497 assert(sprt_entry != NULL, "There should have been an entry");
498 for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
499 CardIdx_t c = sprt_entry->card(i);
500 if (c != SparsePRTEntry::NullEntry) {
501 prt->add_card(c);
502 }
503 }
504 // Now we can delete the sparse entry.
505 bool res = _sparse_table.delete_entry(from_hrs_ind);
506 assert(res, "It should have been there.");
507 }
508 }
509 assert(prt != NULL && prt->hr() == from_hr, "consequence");
510 }
511 // Note that we can't assert "prt->hr() == from_hr", because of the
512 // possibility of concurrent reuse. But see head comment of
513 // OtherRegionsTable for why this is OK.
514 assert(prt != NULL, "Inv");
515
516 prt->add_reference(from);
517
518 if (G1RecordHRRSOops) {
519 HeapRegionRemSet::record(hr(), from);
520 if (G1TraceHeapRegionRememberedSet) {
521 gclog_or_tty->print("Added card " PTR_FORMAT " to region "
522 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
523 align_size_down(uintptr_t(from),
524 CardTableModRefBS::card_size),
525 hr()->bottom(), from);
526 }
527 }
528 assert(contains_reference(from), "We just added it!");
529 }
530
531 PerRegionTable*
532 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
533 assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
534 PerRegionTable* prt = _fine_grain_regions[ind];
535 while (prt != NULL && prt->hr() != hr) {
536 prt = prt->collision_list_next();
537 }
538 // Loop postcondition is the method postcondition.
539 return prt;
540 }
541
542 jint OtherRegionsTable::_n_coarsenings = 0;
543
544 PerRegionTable* OtherRegionsTable::delete_region_table() {
545 assert(_m.owned_by_self(), "Precondition");
546 assert(_n_fine_entries == _max_fine_entries, "Precondition");
547 PerRegionTable* max = NULL;
548 jint max_occ = 0;
549 PerRegionTable** max_prev;
550 size_t max_ind;
551
552 size_t i = _fine_eviction_start;
553 for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
554 size_t ii = i;
555 // Make sure we get a non-NULL sample.
556 while (_fine_grain_regions[ii] == NULL) {
557 ii++;
558 if (ii == _max_fine_entries) ii = 0;
559 guarantee(ii != i, "We must find one.");
560 }
561 PerRegionTable** prev = &_fine_grain_regions[ii];
562 PerRegionTable* cur = *prev;
563 while (cur != NULL) {
564 jint cur_occ = cur->occupied();
565 if (max == NULL || cur_occ > max_occ) {
566 max = cur;
567 max_prev = prev;
568 max_ind = i;
569 max_occ = cur_occ;
570 }
571 prev = cur->collision_list_next_addr();
572 cur = cur->collision_list_next();
573 }
574 i = i + _fine_eviction_stride;
575 if (i >= _n_fine_entries) i = i - _n_fine_entries;
576 }
577
578 _fine_eviction_start++;
579
580 if (_fine_eviction_start >= _n_fine_entries) {
581 _fine_eviction_start -= _n_fine_entries;
582 }
583
584 guarantee(max != NULL, "Since _n_fine_entries > 0");
585
586 // Set the corresponding coarse bit.
587 size_t max_hrs_index = (size_t) max->hr()->hrs_index();
588 if (!_coarse_map.at(max_hrs_index)) {
589 _coarse_map.at_put(max_hrs_index, true);
590 _n_coarse_entries++;
591 if (G1TraceHeapRegionRememberedSet) {
592 gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
593 "for region [" PTR_FORMAT "...] (%d coarse entries).\n",
594 hr()->bottom(),
595 max->hr()->bottom(),
596 _n_coarse_entries);
597 }
598 }
599
600 // Unsplice.
601 *max_prev = max->collision_list_next();
602 Atomic::inc(&_n_coarsenings);
603 _n_fine_entries--;
604 return max;
605 }
606
607
608 // At present, this must be called stop-world single-threaded.
609 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
610 BitMap* region_bm, BitMap* card_bm) {
611 // First eliminated garbage regions from the coarse map.
612 if (G1RSScrubVerbose) {
613 gclog_or_tty->print_cr("Scrubbing region %u:", hr()->hrs_index());
614 }
615
616 assert(_coarse_map.size() == region_bm->size(), "Precondition");
617 if (G1RSScrubVerbose) {
618 gclog_or_tty->print(" Coarse map: before = "SIZE_FORMAT"...",
619 _n_coarse_entries);
620 }
621 _coarse_map.set_intersection(*region_bm);
622 _n_coarse_entries = _coarse_map.count_one_bits();
623 if (G1RSScrubVerbose) {
624 gclog_or_tty->print_cr(" after = "SIZE_FORMAT".", _n_coarse_entries);
625 }
626
627 // Now do the fine-grained maps.
628 for (size_t i = 0; i < _max_fine_entries; i++) {
629 PerRegionTable* cur = _fine_grain_regions[i];
630 PerRegionTable** prev = &_fine_grain_regions[i];
631 while (cur != NULL) {
632 PerRegionTable* nxt = cur->collision_list_next();
633 // If the entire region is dead, eliminate.
634 if (G1RSScrubVerbose) {
635 gclog_or_tty->print_cr(" For other region %u:",
636 cur->hr()->hrs_index());
637 }
638 if (!region_bm->at((size_t) cur->hr()->hrs_index())) {
639 *prev = nxt;
640 cur->set_collision_list_next(NULL);
641 _n_fine_entries--;
642 if (G1RSScrubVerbose) {
643 gclog_or_tty->print_cr(" deleted via region map.");
644 }
645 unlink_from_all(cur);
646 PerRegionTable::free(cur);
647 } else {
648 // Do fine-grain elimination.
649 if (G1RSScrubVerbose) {
650 gclog_or_tty->print(" occ: before = %4d.", cur->occupied());
651 }
652 cur->scrub(ctbs, card_bm);
653 if (G1RSScrubVerbose) {
654 gclog_or_tty->print_cr(" after = %4d.", cur->occupied());
655 }
656 // Did that empty the table completely?
657 if (cur->occupied() == 0) {
658 *prev = nxt;
659 cur->set_collision_list_next(NULL);
660 _n_fine_entries--;
661 unlink_from_all(cur);
662 PerRegionTable::free(cur);
663 } else {
664 prev = cur->collision_list_next_addr();
665 }
666 }
667 cur = nxt;
668 }
669 }
670 // Since we may have deleted a from_card_cache entry from the RS, clear
671 // the FCC.
672 clear_fcc();
673 }
674
675
676 size_t OtherRegionsTable::occupied() const {
677 // Cast away const in this case.
678 MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
679 size_t sum = occ_fine();
680 sum += occ_sparse();
681 sum += occ_coarse();
682 return sum;
683 }
684
685 size_t OtherRegionsTable::occ_fine() const {
686 size_t sum = 0;
687
688 size_t num = 0;
689 PerRegionTable * cur = _first_all_fine_prts;
690 while (cur != NULL) {
691 sum += cur->occupied();
692 cur = cur->next();
693 num++;
694 }
695 guarantee(num == _n_fine_entries, "just checking");
696 return sum;
697 }
698
699 size_t OtherRegionsTable::occ_coarse() const {
700 return (_n_coarse_entries * HeapRegion::CardsPerRegion);
701 }
702
703 size_t OtherRegionsTable::occ_sparse() const {
704 return _sparse_table.occupied();
705 }
706
707 size_t OtherRegionsTable::mem_size() const {
708 // Cast away const in this case.
709 MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
710 size_t sum = 0;
711 PerRegionTable * cur = _first_all_fine_prts;
712 while (cur != NULL) {
713 sum += cur->mem_size();
714 cur = cur->next();
715 }
716 sum += (sizeof(PerRegionTable*) * _max_fine_entries);
717 sum += (_coarse_map.size_in_words() * HeapWordSize);
718 sum += (_sparse_table.mem_size());
719 sum += sizeof(*this) - sizeof(_sparse_table); // Avoid double counting above.
720 return sum;
721 }
722
723 size_t OtherRegionsTable::static_mem_size() {
724 return _from_card_cache_mem_size;
725 }
726
727 size_t OtherRegionsTable::fl_mem_size() {
728 return PerRegionTable::fl_mem_size();
729 }
730
731 void OtherRegionsTable::clear_fcc() {
732 size_t hrs_idx = hr()->hrs_index();
733 for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
734 _from_card_cache[i][hrs_idx] = -1;
735 }
736 }
737
738 void OtherRegionsTable::clear() {
739 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
740 // if there are no entries, skip this step
741 if (_first_all_fine_prts != NULL) {
742 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
743 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
744 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
745 } else {
746 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
747 }
748
749 _first_all_fine_prts = _last_all_fine_prts = NULL;
750 _sparse_table.clear();
751 _coarse_map.clear();
752 _n_fine_entries = 0;
753 _n_coarse_entries = 0;
754
755 clear_fcc();
756 }
757
758 void OtherRegionsTable::clear_incoming_entry(HeapRegion* from_hr) {
759 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
760 size_t hrs_ind = (size_t) from_hr->hrs_index();
761 size_t ind = hrs_ind & _mod_max_fine_entries_mask;
762 if (del_single_region_table(ind, from_hr)) {
763 assert(!_coarse_map.at(hrs_ind), "Inv");
764 } else {
765 _coarse_map.par_at_put(hrs_ind, 0);
766 }
767 // Check to see if any of the fcc entries come from here.
768 size_t hr_ind = (size_t) hr()->hrs_index();
769 for (int tid = 0; tid < HeapRegionRemSet::num_par_rem_sets(); tid++) {
770 int fcc_ent = _from_card_cache[tid][hr_ind];
771 if (fcc_ent != -1) {
772 HeapWord* card_addr = (HeapWord*)
773 (uintptr_t(fcc_ent) << CardTableModRefBS::card_shift);
774 if (hr()->is_in_reserved(card_addr)) {
775 // Clear the from card cache.
776 _from_card_cache[tid][hr_ind] = -1;
777 }
778 }
779 }
780 }
781
782 bool OtherRegionsTable::del_single_region_table(size_t ind,
783 HeapRegion* hr) {
784 assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
785 PerRegionTable** prev_addr = &_fine_grain_regions[ind];
786 PerRegionTable* prt = *prev_addr;
787 while (prt != NULL && prt->hr() != hr) {
788 prev_addr = prt->collision_list_next_addr();
789 prt = prt->collision_list_next();
790 }
791 if (prt != NULL) {
792 assert(prt->hr() == hr, "Loop postcondition.");
793 *prev_addr = prt->collision_list_next();
794 unlink_from_all(prt);
795 PerRegionTable::free(prt);
796 _n_fine_entries--;
797 return true;
798 } else {
799 return false;
800 }
801 }
802
803 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
804 // Cast away const in this case.
805 MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
806 return contains_reference_locked(from);
807 }
808
809 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
810 HeapRegion* hr = _g1h->heap_region_containing_raw(from);
811 if (hr == NULL) return false;
812 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrs_index();
813 // Is this region in the coarse map?
814 if (_coarse_map.at(hr_ind)) return true;
815
816 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
817 hr);
818 if (prt != NULL) {
819 return prt->contains_reference(from);
820
821 } else {
822 uintptr_t from_card =
823 (uintptr_t(from) >> CardTableModRefBS::card_shift);
824 uintptr_t hr_bot_card_index =
825 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
826 assert(from_card >= hr_bot_card_index, "Inv");
827 CardIdx_t card_index = from_card - hr_bot_card_index;
828 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
829 "Must be in range.");
830 return _sparse_table.contains_card(hr_ind, card_index);
831 }
832
833
834 }
835
836 void
837 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
838 _sparse_table.do_cleanup_work(hrrs_cleanup_task);
839 }
840
841 // Determines how many threads can add records to an rset in parallel.
842 // This can be done by either mutator threads together with the
843 // concurrent refinement threads or GC threads.
844 int HeapRegionRemSet::num_par_rem_sets() {
845 return (int)MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), ParallelGCThreads);
846 }
847
848 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
849 HeapRegion* hr)
850 : _bosa(bosa), _other_regions(hr) {
851 reset_for_par_iteration();
852 }
853
854 void HeapRegionRemSet::setup_remset_size() {
855 // Setup sparse and fine-grain tables sizes.
856 // table_size = base * (log(region_size / 1M) + 1)
857 const int LOG_M = 20;
858 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
859 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
860 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
861 }
862 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
863 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
864 }
865 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
866 }
867
868 bool HeapRegionRemSet::claim_iter() {
869 if (_iter_state != Unclaimed) return false;
870 jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
871 return (res == Unclaimed);
872 }
873
874 void HeapRegionRemSet::set_iter_complete() {
875 _iter_state = Complete;
876 }
877
878 bool HeapRegionRemSet::iter_is_complete() {
879 return _iter_state == Complete;
880 }
881
882 #ifndef PRODUCT
883 void HeapRegionRemSet::print() const {
884 HeapRegionRemSetIterator iter(this);
885 size_t card_index;
886 while (iter.has_next(card_index)) {
887 HeapWord* card_start =
888 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
889 gclog_or_tty->print_cr(" Card " PTR_FORMAT, card_start);
890 }
891 if (iter.n_yielded() != occupied()) {
892 gclog_or_tty->print_cr("Yielded disagrees with occupied:");
893 gclog_or_tty->print_cr(" %6d yielded (%6d coarse, %6d fine).",
894 iter.n_yielded(),
895 iter.n_yielded_coarse(), iter.n_yielded_fine());
896 gclog_or_tty->print_cr(" %6d occ (%6d coarse, %6d fine).",
897 occupied(), occ_coarse(), occ_fine());
898 }
899 guarantee(iter.n_yielded() == occupied(),
900 "We should have yielded all the represented cards.");
901 }
902 #endif
903
904 void HeapRegionRemSet::cleanup() {
905 SparsePRT::cleanup_all();
906 }
907
908 void HeapRegionRemSet::clear() {
909 _other_regions.clear();
910 assert(occupied() == 0, "Should be clear.");
911 reset_for_par_iteration();
912 }
913
914 void HeapRegionRemSet::reset_for_par_iteration() {
915 _iter_state = Unclaimed;
916 _iter_claimed = 0;
917 // It's good to check this to make sure that the two methods are in sync.
918 assert(verify_ready_for_par_iteration(), "post-condition");
919 }
920
921 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
922 BitMap* region_bm, BitMap* card_bm) {
923 _other_regions.scrub(ctbs, region_bm, card_bm);
924 }
925
926 //-------------------- Iteration --------------------
927
928 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(const HeapRegionRemSet* hrrs) :
929 _hrrs(hrrs),
930 _g1h(G1CollectedHeap::heap()),
931 _coarse_map(&hrrs->_other_regions._coarse_map),
932 _fine_grain_regions(hrrs->_other_regions._fine_grain_regions),
933 _bosa(hrrs->bosa()),
934 _is(Sparse),
935 // Set these values so that we increment to the first region.
936 _coarse_cur_region_index(-1),
937 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
938 _cur_region_cur_card(0),
939 _fine_array_index(-1),
940 _fine_cur_prt(NULL),
941 _n_yielded_coarse(0),
942 _n_yielded_fine(0),
943 _n_yielded_sparse(0),
944 _sparse_iter(&hrrs->_other_regions._sparse_table) {}
945
946 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
947 if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
948 // Go to the next card.
949 _coarse_cur_region_cur_card++;
950 // Was the last the last card in the current region?
951 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
952 // Yes: find the next region. This may leave _coarse_cur_region_index
953 // Set to the last index, in which case there are no more coarse
954 // regions.
955 _coarse_cur_region_index =
956 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
957 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
958 _coarse_cur_region_cur_card = 0;
959 HeapWord* r_bot =
960 _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
961 _cur_region_card_offset = _bosa->index_for(r_bot);
962 } else {
963 return false;
964 }
965 }
966 // If we didn't return false above, then we can yield a card.
967 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
968 return true;
969 }
970
971 void HeapRegionRemSetIterator::fine_find_next_non_null_prt() {
972 // Otherwise, find the next bucket list in the array.
973 _fine_array_index++;
974 while (_fine_array_index < (int) OtherRegionsTable::_max_fine_entries) {
975 _fine_cur_prt = _fine_grain_regions[_fine_array_index];
976 if (_fine_cur_prt != NULL) return;
977 else _fine_array_index++;
978 }
979 assert(_fine_cur_prt == NULL, "Loop post");
980 }
981
982 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
983 if (fine_has_next()) {
984 _cur_region_cur_card =
985 _fine_cur_prt->_bm.get_next_one_offset(_cur_region_cur_card + 1);
986 }
987 while (!fine_has_next()) {
988 if (_cur_region_cur_card == (size_t) HeapRegion::CardsPerRegion) {
989 _cur_region_cur_card = 0;
990 _fine_cur_prt = _fine_cur_prt->collision_list_next();
991 }
992 if (_fine_cur_prt == NULL) {
993 fine_find_next_non_null_prt();
994 if (_fine_cur_prt == NULL) return false;
995 }
996 assert(_fine_cur_prt != NULL && _cur_region_cur_card == 0,
997 "inv.");
998 HeapWord* r_bot =
999 _fine_cur_prt->hr()->bottom();
1000 _cur_region_card_offset = _bosa->index_for(r_bot);
1001 _cur_region_cur_card = _fine_cur_prt->_bm.get_next_one_offset(0);
1002 }
1003 assert(fine_has_next(), "Or else we exited the loop via the return.");
1004 card_index = _cur_region_card_offset + _cur_region_cur_card;
1005 return true;
1006 }
1007
1008 bool HeapRegionRemSetIterator::fine_has_next() {
1009 return
1010 _fine_cur_prt != NULL &&
1011 _cur_region_cur_card < HeapRegion::CardsPerRegion;
1012 }
1013
1014 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
1015 switch (_is) {
1016 case Sparse:
1017 if (_sparse_iter.has_next(card_index)) {
1018 _n_yielded_sparse++;
1019 return true;
1020 }
1021 // Otherwise, deliberate fall-through
1022 _is = Fine;
1023 case Fine:
1024 if (fine_has_next(card_index)) {
1025 _n_yielded_fine++;
1026 return true;
1027 }
1028 // Otherwise, deliberate fall-through
1029 _is = Coarse;
1030 case Coarse:
1031 if (coarse_has_next(card_index)) {
1032 _n_yielded_coarse++;
1033 return true;
1034 }
1035 // Otherwise...
1036 break;
1037 }
1038 assert(ParallelGCThreads > 1 ||
1039 n_yielded() == _hrrs->occupied(),
1040 "Should have yielded all the cards in the rem set "
1041 "(in the non-par case).");
1042 return false;
1043 }
1044
1045
1046
1047 OopOrNarrowOopStar* HeapRegionRemSet::_recorded_oops = NULL;
1048 HeapWord** HeapRegionRemSet::_recorded_cards = NULL;
1049 HeapRegion** HeapRegionRemSet::_recorded_regions = NULL;
1050 int HeapRegionRemSet::_n_recorded = 0;
1051
1052 HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
1053 int* HeapRegionRemSet::_recorded_event_index = NULL;
1054 int HeapRegionRemSet::_n_recorded_events = 0;
1055
1056 void HeapRegionRemSet::record(HeapRegion* hr, OopOrNarrowOopStar f) {
1057 if (_recorded_oops == NULL) {
1058 assert(_n_recorded == 0
1059 && _recorded_cards == NULL
1060 && _recorded_regions == NULL,
1061 "Inv");
1062 _recorded_oops = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
1063 _recorded_cards = NEW_C_HEAP_ARRAY(HeapWord*, MaxRecorded, mtGC);
1064 _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*, MaxRecorded, mtGC);
1065 }
1066 if (_n_recorded == MaxRecorded) {
1067 gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
1068 } else {
1069 _recorded_cards[_n_recorded] =
1070 (HeapWord*)align_size_down(uintptr_t(f),
1071 CardTableModRefBS::card_size);
1072 _recorded_oops[_n_recorded] = f;
1073 _recorded_regions[_n_recorded] = hr;
1074 _n_recorded++;
1075 }
1076 }
1077
1078 void HeapRegionRemSet::record_event(Event evnt) {
1079 if (!G1RecordHRRSEvents) return;
1080
1081 if (_recorded_events == NULL) {
1082 assert(_n_recorded_events == 0
1083 && _recorded_event_index == NULL,
1084 "Inv");
1085 _recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents, mtGC);
1086 _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
1087 }
1088 if (_n_recorded_events == MaxRecordedEvents) {
1089 gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
1090 } else {
1091 _recorded_events[_n_recorded_events] = evnt;
1092 _recorded_event_index[_n_recorded_events] = _n_recorded;
1093 _n_recorded_events++;
1094 }
1095 }
1096
1097 void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
1098 switch (evnt) {
1099 case Event_EvacStart:
1100 str->print("Evac Start");
1101 break;
1102 case Event_EvacEnd:
1103 str->print("Evac End");
1104 break;
1105 case Event_RSUpdateEnd:
1106 str->print("RS Update End");
1107 break;
1108 }
1109 }
1110
1111 void HeapRegionRemSet::print_recorded() {
1112 int cur_evnt = 0;
1113 Event cur_evnt_kind;
1114 int cur_evnt_ind = 0;
1115 if (_n_recorded_events > 0) {
1116 cur_evnt_kind = _recorded_events[cur_evnt];
1117 cur_evnt_ind = _recorded_event_index[cur_evnt];
1118 }
1119
1120 for (int i = 0; i < _n_recorded; i++) {
1121 while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
1122 gclog_or_tty->print("Event: ");
1123 print_event(gclog_or_tty, cur_evnt_kind);
1124 gclog_or_tty->print_cr("");
1125 cur_evnt++;
1126 if (cur_evnt < MaxRecordedEvents) {
1127 cur_evnt_kind = _recorded_events[cur_evnt];
1128 cur_evnt_ind = _recorded_event_index[cur_evnt];
1129 }
1130 }
1131 gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
1132 " for ref " PTR_FORMAT ".\n",
1133 _recorded_cards[i], _recorded_regions[i]->bottom(),
1134 _recorded_oops[i]);
1135 }
1136 }
1137
1138 void HeapRegionRemSet::reset_for_cleanup_tasks() {
1139 SparsePRT::reset_for_cleanup_tasks();
1140 }
1141
1142 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
1143 _other_regions.do_cleanup_work(hrrs_cleanup_task);
1144 }
1145
1146 void
1147 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
1148 SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
1149 }
1150
1151 #ifndef PRODUCT
1152 void PerRegionTable::test_fl_mem_size() {
1153 PerRegionTable* dummy = alloc(NULL);
1154 free(dummy);
1155 guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
1156 // try to reset the state
1157 _free_list = NULL;
1158 delete dummy;
1159 }
1160
1161 void HeapRegionRemSet::test_prt() {
1162 PerRegionTable::test_fl_mem_size();
1163 }
1164
1165 void HeapRegionRemSet::test() {
1166 os::sleep(Thread::current(), (jlong)5000, false);
1167 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1168
1169 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
1170 // hash bucket.
1171 HeapRegion* hr0 = g1h->region_at(0);
1172 HeapRegion* hr1 = g1h->region_at(1);
1173 HeapRegion* hr2 = g1h->region_at(5);
1174 HeapRegion* hr3 = g1h->region_at(6);
1175 HeapRegion* hr4 = g1h->region_at(7);
1176 HeapRegion* hr5 = g1h->region_at(8);
1177
1178 HeapWord* hr1_start = hr1->bottom();
1179 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
1180 HeapWord* hr1_last = hr1->end() - 1;
1181
1182 HeapWord* hr2_start = hr2->bottom();
1183 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
1184 HeapWord* hr2_last = hr2->end() - 1;
1185
1186 HeapWord* hr3_start = hr3->bottom();
1187 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
1188 HeapWord* hr3_last = hr3->end() - 1;
1189
1190 HeapRegionRemSet* hrrs = hr0->rem_set();
1191
1192 // Make three references from region 0x101...
1193 hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
1194 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
1195 hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
1196
1197 hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
1198 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
1199 hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
1200
1201 hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
1202 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
1203 hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
1204
1205 // Now cause a coarsening.
1206 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
1207 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
1208
1209 // Now, does iteration yield these three?
1210 HeapRegionRemSetIterator iter(hrrs);
1211 size_t sum = 0;
1212 size_t card_index;
1213 while (iter.has_next(card_index)) {
1214 HeapWord* card_start =
1215 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
1216 gclog_or_tty->print_cr(" Card " PTR_FORMAT ".", card_start);
1217 sum++;
1218 }
1219 guarantee(sum == 11 - 3 + 2048, "Failure");
1220 guarantee(sum == hrrs->occupied(), "Failure");
1221 }
1222 #endif