Mon, 01 Feb 2016 13:19:14 -0800
8145442: Add the facility to verify remembered sets for G1
Summary: Implement remembered sets verification for G1 with option VerifyRememberedSets
Reviewed-by: jmasa, mgerdin
1 /*
2 * Copyright (c) 2001, 2016, 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
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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23 */
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/heapRegionManager.inline.hpp"
31 #include "memory/allocation.hpp"
32 #include "memory/padded.inline.hpp"
33 #include "memory/space.inline.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "utilities/bitMap.inline.hpp"
36 #include "utilities/globalDefinitions.hpp"
37 #include "utilities/growableArray.hpp"
39 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
41 class PerRegionTable: public CHeapObj<mtGC> {
42 friend class OtherRegionsTable;
43 friend class HeapRegionRemSetIterator;
45 HeapRegion* _hr;
46 BitMap _bm;
47 jint _occupied;
49 // next pointer for free/allocated 'all' list
50 PerRegionTable* _next;
52 // prev pointer for the allocated 'all' list
53 PerRegionTable* _prev;
55 // next pointer in collision list
56 PerRegionTable * _collision_list_next;
58 // Global free list of PRTs
59 static PerRegionTable* _free_list;
61 protected:
62 // We need access in order to union things into the base table.
63 BitMap* bm() { return &_bm; }
65 void recount_occupied() {
66 _occupied = (jint) bm()->count_one_bits();
67 }
69 PerRegionTable(HeapRegion* hr) :
70 _hr(hr),
71 _occupied(0),
72 _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
73 _collision_list_next(NULL), _next(NULL), _prev(NULL)
74 {}
76 void add_card_work(CardIdx_t from_card, bool par) {
77 if (!_bm.at(from_card)) {
78 if (par) {
79 if (_bm.par_at_put(from_card, 1)) {
80 Atomic::inc(&_occupied);
81 }
82 } else {
83 _bm.at_put(from_card, 1);
84 _occupied++;
85 }
86 }
87 }
89 void add_reference_work(OopOrNarrowOopStar from, bool par) {
90 // Must make this robust in case "from" is not in "_hr", because of
91 // concurrency.
93 if (G1TraceHeapRegionRememberedSet) {
94 gclog_or_tty->print_cr(" PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
95 from,
96 UseCompressedOops
97 ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
98 : (void *)oopDesc::load_decode_heap_oop((oop*)from));
99 }
101 HeapRegion* loc_hr = hr();
102 // If the test below fails, then this table was reused concurrently
103 // with this operation. This is OK, since the old table was coarsened,
104 // and adding a bit to the new table is never incorrect.
105 // If the table used to belong to a continues humongous region and is
106 // now reused for the corresponding start humongous region, we need to
107 // make sure that we detect this. Thus, we call is_in_reserved_raw()
108 // instead of just is_in_reserved() here.
109 if (loc_hr->is_in_reserved_raw(from)) {
110 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
111 CardIdx_t from_card = (CardIdx_t)
112 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
114 assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
115 "Must be in range.");
116 add_card_work(from_card, par);
117 }
118 }
120 public:
122 HeapRegion* hr() const {
123 return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr);
124 }
126 jint occupied() const {
127 // Overkill, but if we ever need it...
128 // guarantee(_occupied == _bm.count_one_bits(), "Check");
129 return _occupied;
130 }
132 void init(HeapRegion* hr, bool clear_links_to_all_list) {
133 if (clear_links_to_all_list) {
134 set_next(NULL);
135 set_prev(NULL);
136 }
137 _collision_list_next = NULL;
138 _occupied = 0;
139 _bm.clear();
140 // Make sure that the bitmap clearing above has been finished before publishing
141 // this PRT to concurrent threads.
142 OrderAccess::release_store_ptr(&_hr, hr);
143 }
145 void add_reference(OopOrNarrowOopStar from) {
146 add_reference_work(from, /*parallel*/ true);
147 }
149 void seq_add_reference(OopOrNarrowOopStar from) {
150 add_reference_work(from, /*parallel*/ false);
151 }
153 void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
154 HeapWord* hr_bot = hr()->bottom();
155 size_t hr_first_card_index = ctbs->index_for(hr_bot);
156 bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
157 recount_occupied();
158 }
160 void add_card(CardIdx_t from_card_index) {
161 add_card_work(from_card_index, /*parallel*/ true);
162 }
164 void seq_add_card(CardIdx_t from_card_index) {
165 add_card_work(from_card_index, /*parallel*/ false);
166 }
168 // (Destructively) union the bitmap of the current table into the given
169 // bitmap (which is assumed to be of the same size.)
170 void union_bitmap_into(BitMap* bm) {
171 bm->set_union(_bm);
172 }
174 // Mem size in bytes.
175 size_t mem_size() const {
176 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize;
177 }
179 // Requires "from" to be in "hr()".
180 bool contains_reference(OopOrNarrowOopStar from) const {
181 assert(hr()->is_in_reserved(from), "Precondition.");
182 size_t card_ind = pointer_delta(from, hr()->bottom(),
183 CardTableModRefBS::card_size);
184 return _bm.at(card_ind);
185 }
187 // Bulk-free the PRTs from prt to last, assumes that they are
188 // linked together using their _next field.
189 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
190 while (true) {
191 PerRegionTable* fl = _free_list;
192 last->set_next(fl);
193 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
194 if (res == fl) {
195 return;
196 }
197 }
198 ShouldNotReachHere();
199 }
201 static void free(PerRegionTable* prt) {
202 bulk_free(prt, prt);
203 }
205 // Returns an initialized PerRegionTable instance.
206 static PerRegionTable* alloc(HeapRegion* hr) {
207 PerRegionTable* fl = _free_list;
208 while (fl != NULL) {
209 PerRegionTable* nxt = fl->next();
210 PerRegionTable* res =
211 (PerRegionTable*)
212 Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
213 if (res == fl) {
214 fl->init(hr, true);
215 return fl;
216 } else {
217 fl = _free_list;
218 }
219 }
220 assert(fl == NULL, "Loop condition.");
221 return new PerRegionTable(hr);
222 }
224 PerRegionTable* next() const { return _next; }
225 void set_next(PerRegionTable* next) { _next = next; }
226 PerRegionTable* prev() const { return _prev; }
227 void set_prev(PerRegionTable* prev) { _prev = prev; }
229 // Accessor and Modification routines for the pointer for the
230 // singly linked collision list that links the PRTs within the
231 // OtherRegionsTable::_fine_grain_regions hash table.
232 //
233 // It might be useful to also make the collision list doubly linked
234 // to avoid iteration over the collisions list during scrubbing/deletion.
235 // OTOH there might not be many collisions.
237 PerRegionTable* collision_list_next() const {
238 return _collision_list_next;
239 }
241 void set_collision_list_next(PerRegionTable* next) {
242 _collision_list_next = next;
243 }
245 PerRegionTable** collision_list_next_addr() {
246 return &_collision_list_next;
247 }
249 static size_t fl_mem_size() {
250 PerRegionTable* cur = _free_list;
251 size_t res = 0;
252 while (cur != NULL) {
253 res += cur->mem_size();
254 cur = cur->next();
255 }
256 return res;
257 }
259 static void test_fl_mem_size();
260 };
262 PerRegionTable* PerRegionTable::_free_list = NULL;
264 size_t OtherRegionsTable::_max_fine_entries = 0;
265 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
266 size_t OtherRegionsTable::_fine_eviction_stride = 0;
267 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
269 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
270 _g1h(G1CollectedHeap::heap()),
271 _hr(hr), _m(m),
272 _coarse_map(G1CollectedHeap::heap()->max_regions(),
273 false /* in-resource-area */),
274 _fine_grain_regions(NULL),
275 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
276 _n_fine_entries(0), _n_coarse_entries(0),
277 _fine_eviction_start(0),
278 _sparse_table(hr)
279 {
280 typedef PerRegionTable* PerRegionTablePtr;
282 if (_max_fine_entries == 0) {
283 assert(_mod_max_fine_entries_mask == 0, "Both or none.");
284 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
285 _max_fine_entries = (size_t)1 << max_entries_log;
286 _mod_max_fine_entries_mask = _max_fine_entries - 1;
288 assert(_fine_eviction_sample_size == 0
289 && _fine_eviction_stride == 0, "All init at same time.");
290 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
291 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
292 }
294 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
295 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
297 if (_fine_grain_regions == NULL) {
298 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
299 "Failed to allocate _fine_grain_entries.");
300 }
302 for (size_t i = 0; i < _max_fine_entries; i++) {
303 _fine_grain_regions[i] = NULL;
304 }
305 }
307 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
308 // We always append to the beginning of the list for convenience;
309 // the order of entries in this list does not matter.
310 if (_first_all_fine_prts != NULL) {
311 assert(_first_all_fine_prts->prev() == NULL, "invariant");
312 _first_all_fine_prts->set_prev(prt);
313 prt->set_next(_first_all_fine_prts);
314 } else {
315 // this is the first element we insert. Adjust the "last" pointer
316 _last_all_fine_prts = prt;
317 assert(prt->next() == NULL, "just checking");
318 }
319 // the new element is always the first element without a predecessor
320 prt->set_prev(NULL);
321 _first_all_fine_prts = prt;
323 assert(prt->prev() == NULL, "just checking");
324 assert(_first_all_fine_prts == prt, "just checking");
325 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
326 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
327 "just checking");
328 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
329 "just checking");
330 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
331 "just checking");
332 }
334 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
335 if (prt->prev() != NULL) {
336 assert(_first_all_fine_prts != prt, "just checking");
337 prt->prev()->set_next(prt->next());
338 // removing the last element in the list?
339 if (_last_all_fine_prts == prt) {
340 _last_all_fine_prts = prt->prev();
341 }
342 } else {
343 assert(_first_all_fine_prts == prt, "just checking");
344 _first_all_fine_prts = prt->next();
345 // list is empty now?
346 if (_first_all_fine_prts == NULL) {
347 _last_all_fine_prts = NULL;
348 }
349 }
351 if (prt->next() != NULL) {
352 prt->next()->set_prev(prt->prev());
353 }
355 prt->set_next(NULL);
356 prt->set_prev(NULL);
358 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
359 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
360 "just checking");
361 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
362 "just checking");
363 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
364 "just checking");
365 }
367 int** FromCardCache::_cache = NULL;
368 uint FromCardCache::_max_regions = 0;
369 size_t FromCardCache::_static_mem_size = 0;
371 void FromCardCache::initialize(uint n_par_rs, uint max_num_regions) {
372 guarantee(_cache == NULL, "Should not call this multiple times");
374 _max_regions = max_num_regions;
375 _cache = Padded2DArray<int, mtGC>::create_unfreeable(n_par_rs,
376 _max_regions,
377 &_static_mem_size);
379 invalidate(0, _max_regions);
380 }
382 void FromCardCache::invalidate(uint start_idx, size_t new_num_regions) {
383 guarantee((size_t)start_idx + new_num_regions <= max_uintx,
384 err_msg("Trying to invalidate beyond maximum region, from %u size "SIZE_FORMAT,
385 start_idx, new_num_regions));
386 for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
387 uint end_idx = (start_idx + (uint)new_num_regions);
388 assert(end_idx <= _max_regions, "Must be within max.");
389 for (uint j = start_idx; j < end_idx; j++) {
390 set(i, j, InvalidCard);
391 }
392 }
393 }
395 #ifndef PRODUCT
396 void FromCardCache::print(outputStream* out) {
397 for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
398 for (uint j = 0; j < _max_regions; j++) {
399 out->print_cr("_from_card_cache["UINT32_FORMAT"]["UINT32_FORMAT"] = "INT32_FORMAT".",
400 i, j, at(i, j));
401 }
402 }
403 }
404 #endif
406 void FromCardCache::clear(uint region_idx) {
407 uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
408 for (uint i = 0; i < num_par_remsets; i++) {
409 set(i, region_idx, InvalidCard);
410 }
411 }
413 void OtherRegionsTable::initialize(uint max_regions) {
414 FromCardCache::initialize(HeapRegionRemSet::num_par_rem_sets(), max_regions);
415 }
417 void OtherRegionsTable::invalidate(uint start_idx, size_t num_regions) {
418 FromCardCache::invalidate(start_idx, num_regions);
419 }
421 void OtherRegionsTable::print_from_card_cache() {
422 FromCardCache::print();
423 }
425 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, int tid) {
426 uint cur_hrm_ind = hr()->hrm_index();
428 if (G1TraceHeapRegionRememberedSet) {
429 gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
430 from,
431 UseCompressedOops
432 ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
433 : (void *)oopDesc::load_decode_heap_oop((oop*)from));
434 }
436 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
438 if (G1TraceHeapRegionRememberedSet) {
439 gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = "INT32_FORMAT")",
440 hr()->bottom(), from_card,
441 FromCardCache::at((uint)tid, cur_hrm_ind));
442 }
444 if (FromCardCache::contains_or_replace((uint)tid, cur_hrm_ind, from_card)) {
445 if (G1TraceHeapRegionRememberedSet) {
446 gclog_or_tty->print_cr(" from-card cache hit.");
447 }
448 assert(contains_reference(from), err_msg("We just found " PTR_FORMAT " in the FromCardCache", from));
449 return;
450 }
452 // Note that this may be a continued H region.
453 HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
454 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index();
456 // If the region is already coarsened, return.
457 if (_coarse_map.at(from_hrm_ind)) {
458 if (G1TraceHeapRegionRememberedSet) {
459 gclog_or_tty->print_cr(" coarse map hit.");
460 }
461 assert(contains_reference(from), err_msg("We just found " PTR_FORMAT " in the Coarse table", from));
462 return;
463 }
465 // Otherwise find a per-region table to add it to.
466 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask;
467 PerRegionTable* prt = find_region_table(ind, from_hr);
468 if (prt == NULL) {
469 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
470 // Confirm that it's really not there...
471 prt = find_region_table(ind, from_hr);
472 if (prt == NULL) {
474 uintptr_t from_hr_bot_card_index =
475 uintptr_t(from_hr->bottom())
476 >> CardTableModRefBS::card_shift;
477 CardIdx_t card_index = from_card - from_hr_bot_card_index;
478 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
479 "Must be in range.");
480 if (G1HRRSUseSparseTable &&
481 _sparse_table.add_card(from_hrm_ind, card_index)) {
482 if (G1RecordHRRSOops) {
483 HeapRegionRemSet::record(hr(), from);
484 if (G1TraceHeapRegionRememberedSet) {
485 gclog_or_tty->print(" Added card " PTR_FORMAT " to region "
486 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
487 align_size_down(uintptr_t(from),
488 CardTableModRefBS::card_size),
489 hr()->bottom(), from);
490 }
491 }
492 if (G1TraceHeapRegionRememberedSet) {
493 gclog_or_tty->print_cr(" added card to sparse table.");
494 }
495 assert(contains_reference_locked(from), err_msg("We just added " PTR_FORMAT " to the Sparse table", from));
496 return;
497 } else {
498 if (G1TraceHeapRegionRememberedSet) {
499 gclog_or_tty->print_cr(" [tid %d] sparse table entry "
500 "overflow(f: %d, t: %u)",
501 tid, from_hrm_ind, cur_hrm_ind);
502 }
503 }
505 if (_n_fine_entries == _max_fine_entries) {
506 prt = delete_region_table();
507 // There is no need to clear the links to the 'all' list here:
508 // prt will be reused immediately, i.e. remain in the 'all' list.
509 prt->init(from_hr, false /* clear_links_to_all_list */);
510 } else {
511 prt = PerRegionTable::alloc(from_hr);
512 link_to_all(prt);
513 }
515 PerRegionTable* first_prt = _fine_grain_regions[ind];
516 prt->set_collision_list_next(first_prt);
517 _fine_grain_regions[ind] = prt;
518 _n_fine_entries++;
520 if (G1HRRSUseSparseTable) {
521 // Transfer from sparse to fine-grain.
522 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind);
523 assert(sprt_entry != NULL, "There should have been an entry");
524 for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
525 CardIdx_t c = sprt_entry->card(i);
526 if (c != SparsePRTEntry::NullEntry) {
527 prt->add_card(c);
528 }
529 }
530 // Now we can delete the sparse entry.
531 bool res = _sparse_table.delete_entry(from_hrm_ind);
532 assert(res, "It should have been there.");
533 }
534 }
535 assert(prt != NULL && prt->hr() == from_hr, "consequence");
536 }
537 // Note that we can't assert "prt->hr() == from_hr", because of the
538 // possibility of concurrent reuse. But see head comment of
539 // OtherRegionsTable for why this is OK.
540 assert(prt != NULL, "Inv");
542 prt->add_reference(from);
544 if (G1RecordHRRSOops) {
545 HeapRegionRemSet::record(hr(), from);
546 if (G1TraceHeapRegionRememberedSet) {
547 gclog_or_tty->print("Added card " PTR_FORMAT " to region "
548 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
549 align_size_down(uintptr_t(from),
550 CardTableModRefBS::card_size),
551 hr()->bottom(), from);
552 }
553 }
554 assert(contains_reference(from), err_msg("We just added " PTR_FORMAT " to the PRT", from));
555 }
557 PerRegionTable*
558 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
559 assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
560 PerRegionTable* prt = _fine_grain_regions[ind];
561 while (prt != NULL && prt->hr() != hr) {
562 prt = prt->collision_list_next();
563 }
564 // Loop postcondition is the method postcondition.
565 return prt;
566 }
568 jint OtherRegionsTable::_n_coarsenings = 0;
570 PerRegionTable* OtherRegionsTable::delete_region_table() {
571 assert(_m->owned_by_self(), "Precondition");
572 assert(_n_fine_entries == _max_fine_entries, "Precondition");
573 PerRegionTable* max = NULL;
574 jint max_occ = 0;
575 PerRegionTable** max_prev;
576 size_t max_ind;
578 size_t i = _fine_eviction_start;
579 for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
580 size_t ii = i;
581 // Make sure we get a non-NULL sample.
582 while (_fine_grain_regions[ii] == NULL) {
583 ii++;
584 if (ii == _max_fine_entries) ii = 0;
585 guarantee(ii != i, "We must find one.");
586 }
587 PerRegionTable** prev = &_fine_grain_regions[ii];
588 PerRegionTable* cur = *prev;
589 while (cur != NULL) {
590 jint cur_occ = cur->occupied();
591 if (max == NULL || cur_occ > max_occ) {
592 max = cur;
593 max_prev = prev;
594 max_ind = i;
595 max_occ = cur_occ;
596 }
597 prev = cur->collision_list_next_addr();
598 cur = cur->collision_list_next();
599 }
600 i = i + _fine_eviction_stride;
601 if (i >= _n_fine_entries) i = i - _n_fine_entries;
602 }
604 _fine_eviction_start++;
606 if (_fine_eviction_start >= _n_fine_entries) {
607 _fine_eviction_start -= _n_fine_entries;
608 }
610 guarantee(max != NULL, "Since _n_fine_entries > 0");
612 // Set the corresponding coarse bit.
613 size_t max_hrm_index = (size_t) max->hr()->hrm_index();
614 if (!_coarse_map.at(max_hrm_index)) {
615 _coarse_map.at_put(max_hrm_index, true);
616 _n_coarse_entries++;
617 if (G1TraceHeapRegionRememberedSet) {
618 gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
619 "for region [" PTR_FORMAT "...] (%d coarse entries).\n",
620 hr()->bottom(),
621 max->hr()->bottom(),
622 _n_coarse_entries);
623 }
624 }
626 // Unsplice.
627 *max_prev = max->collision_list_next();
628 Atomic::inc(&_n_coarsenings);
629 _n_fine_entries--;
630 return max;
631 }
634 // At present, this must be called stop-world single-threaded.
635 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
636 BitMap* region_bm, BitMap* card_bm) {
637 // First eliminated garbage regions from the coarse map.
638 if (G1RSScrubVerbose) {
639 gclog_or_tty->print_cr("Scrubbing region %u:", hr()->hrm_index());
640 }
642 assert(_coarse_map.size() == region_bm->size(), "Precondition");
643 if (G1RSScrubVerbose) {
644 gclog_or_tty->print(" Coarse map: before = "SIZE_FORMAT"...",
645 _n_coarse_entries);
646 }
647 _coarse_map.set_intersection(*region_bm);
648 _n_coarse_entries = _coarse_map.count_one_bits();
649 if (G1RSScrubVerbose) {
650 gclog_or_tty->print_cr(" after = "SIZE_FORMAT".", _n_coarse_entries);
651 }
653 // Now do the fine-grained maps.
654 for (size_t i = 0; i < _max_fine_entries; i++) {
655 PerRegionTable* cur = _fine_grain_regions[i];
656 PerRegionTable** prev = &_fine_grain_regions[i];
657 while (cur != NULL) {
658 PerRegionTable* nxt = cur->collision_list_next();
659 // If the entire region is dead, eliminate.
660 if (G1RSScrubVerbose) {
661 gclog_or_tty->print_cr(" For other region %u:",
662 cur->hr()->hrm_index());
663 }
664 if (!region_bm->at((size_t) cur->hr()->hrm_index())) {
665 *prev = nxt;
666 cur->set_collision_list_next(NULL);
667 _n_fine_entries--;
668 if (G1RSScrubVerbose) {
669 gclog_or_tty->print_cr(" deleted via region map.");
670 }
671 unlink_from_all(cur);
672 PerRegionTable::free(cur);
673 } else {
674 // Do fine-grain elimination.
675 if (G1RSScrubVerbose) {
676 gclog_or_tty->print(" occ: before = %4d.", cur->occupied());
677 }
678 cur->scrub(ctbs, card_bm);
679 if (G1RSScrubVerbose) {
680 gclog_or_tty->print_cr(" after = %4d.", cur->occupied());
681 }
682 // Did that empty the table completely?
683 if (cur->occupied() == 0) {
684 *prev = nxt;
685 cur->set_collision_list_next(NULL);
686 _n_fine_entries--;
687 unlink_from_all(cur);
688 PerRegionTable::free(cur);
689 } else {
690 prev = cur->collision_list_next_addr();
691 }
692 }
693 cur = nxt;
694 }
695 }
696 // Since we may have deleted a from_card_cache entry from the RS, clear
697 // the FCC.
698 clear_fcc();
699 }
701 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const {
702 if (limit <= (size_t)G1RSetSparseRegionEntries) {
703 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit;
704 } else {
705 // Current uses of this method may only use values less than G1RSetSparseRegionEntries
706 // for the limit. The solution, comparing against occupied() would be too slow
707 // at this time.
708 Unimplemented();
709 return false;
710 }
711 }
713 bool OtherRegionsTable::is_empty() const {
714 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL;
715 }
717 size_t OtherRegionsTable::occupied() const {
718 size_t sum = occ_fine();
719 sum += occ_sparse();
720 sum += occ_coarse();
721 return sum;
722 }
724 size_t OtherRegionsTable::occ_fine() const {
725 size_t sum = 0;
727 size_t num = 0;
728 PerRegionTable * cur = _first_all_fine_prts;
729 while (cur != NULL) {
730 sum += cur->occupied();
731 cur = cur->next();
732 num++;
733 }
734 guarantee(num == _n_fine_entries, "just checking");
735 return sum;
736 }
738 size_t OtherRegionsTable::occ_coarse() const {
739 return (_n_coarse_entries * HeapRegion::CardsPerRegion);
740 }
742 size_t OtherRegionsTable::occ_sparse() const {
743 return _sparse_table.occupied();
744 }
746 size_t OtherRegionsTable::mem_size() const {
747 size_t sum = 0;
748 // all PRTs are of the same size so it is sufficient to query only one of them.
749 if (_first_all_fine_prts != NULL) {
750 assert(_last_all_fine_prts != NULL &&
751 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
752 sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
753 }
754 sum += (sizeof(PerRegionTable*) * _max_fine_entries);
755 sum += (_coarse_map.size_in_words() * HeapWordSize);
756 sum += (_sparse_table.mem_size());
757 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above.
758 return sum;
759 }
761 size_t OtherRegionsTable::static_mem_size() {
762 return FromCardCache::static_mem_size();
763 }
765 size_t OtherRegionsTable::fl_mem_size() {
766 return PerRegionTable::fl_mem_size();
767 }
769 void OtherRegionsTable::clear_fcc() {
770 FromCardCache::clear(hr()->hrm_index());
771 }
773 void OtherRegionsTable::clear() {
774 // if there are no entries, skip this step
775 if (_first_all_fine_prts != NULL) {
776 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
777 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
778 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
779 } else {
780 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
781 }
783 _first_all_fine_prts = _last_all_fine_prts = NULL;
784 _sparse_table.clear();
785 _coarse_map.clear();
786 _n_fine_entries = 0;
787 _n_coarse_entries = 0;
789 clear_fcc();
790 }
792 bool OtherRegionsTable::del_single_region_table(size_t ind,
793 HeapRegion* hr) {
794 assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
795 PerRegionTable** prev_addr = &_fine_grain_regions[ind];
796 PerRegionTable* prt = *prev_addr;
797 while (prt != NULL && prt->hr() != hr) {
798 prev_addr = prt->collision_list_next_addr();
799 prt = prt->collision_list_next();
800 }
801 if (prt != NULL) {
802 assert(prt->hr() == hr, "Loop postcondition.");
803 *prev_addr = prt->collision_list_next();
804 unlink_from_all(prt);
805 PerRegionTable::free(prt);
806 _n_fine_entries--;
807 return true;
808 } else {
809 return false;
810 }
811 }
813 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
814 // Cast away const in this case.
815 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag);
816 return contains_reference_locked(from);
817 }
819 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
820 HeapRegion* hr = _g1h->heap_region_containing_raw(from);
821 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index();
822 // Is this region in the coarse map?
823 if (_coarse_map.at(hr_ind)) return true;
825 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
826 hr);
827 if (prt != NULL) {
828 return prt->contains_reference(from);
830 } else {
831 uintptr_t from_card =
832 (uintptr_t(from) >> CardTableModRefBS::card_shift);
833 uintptr_t hr_bot_card_index =
834 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
835 assert(from_card >= hr_bot_card_index, "Inv");
836 CardIdx_t card_index = from_card - hr_bot_card_index;
837 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
838 "Must be in range.");
839 return _sparse_table.contains_card(hr_ind, card_index);
840 }
841 }
843 void
844 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
845 _sparse_table.do_cleanup_work(hrrs_cleanup_task);
846 }
848 // Determines how many threads can add records to an rset in parallel.
849 // This can be done by either mutator threads together with the
850 // concurrent refinement threads or GC threads.
851 uint HeapRegionRemSet::num_par_rem_sets() {
852 return MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), (uint)ParallelGCThreads);
853 }
855 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
856 HeapRegion* hr)
857 : _bosa(bosa),
858 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true),
859 _code_roots(), _other_regions(hr, &_m), _iter_state(Unclaimed), _iter_claimed(0) {
860 reset_for_par_iteration();
861 }
863 void HeapRegionRemSet::setup_remset_size() {
864 // Setup sparse and fine-grain tables sizes.
865 // table_size = base * (log(region_size / 1M) + 1)
866 const int LOG_M = 20;
867 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
868 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
869 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
870 }
871 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
872 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
873 }
874 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
875 }
877 bool HeapRegionRemSet::claim_iter() {
878 if (_iter_state != Unclaimed) return false;
879 jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
880 return (res == Unclaimed);
881 }
883 void HeapRegionRemSet::set_iter_complete() {
884 _iter_state = Complete;
885 }
887 bool HeapRegionRemSet::iter_is_complete() {
888 return _iter_state == Complete;
889 }
891 #ifndef PRODUCT
892 void HeapRegionRemSet::print() {
893 HeapRegionRemSetIterator iter(this);
894 size_t card_index;
895 while (iter.has_next(card_index)) {
896 HeapWord* card_start =
897 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
898 gclog_or_tty->print_cr(" Card " PTR_FORMAT, card_start);
899 }
900 if (iter.n_yielded() != occupied()) {
901 gclog_or_tty->print_cr("Yielded disagrees with occupied:");
902 gclog_or_tty->print_cr(" %6d yielded (%6d coarse, %6d fine).",
903 iter.n_yielded(),
904 iter.n_yielded_coarse(), iter.n_yielded_fine());
905 gclog_or_tty->print_cr(" %6d occ (%6d coarse, %6d fine).",
906 occupied(), occ_coarse(), occ_fine());
907 }
908 guarantee(iter.n_yielded() == occupied(),
909 "We should have yielded all the represented cards.");
910 }
911 #endif
913 void HeapRegionRemSet::cleanup() {
914 SparsePRT::cleanup_all();
915 }
917 void HeapRegionRemSet::clear() {
918 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
919 clear_locked();
920 }
922 void HeapRegionRemSet::clear_locked() {
923 _code_roots.clear();
924 _other_regions.clear();
925 assert(occupied_locked() == 0, "Should be clear.");
926 reset_for_par_iteration();
927 }
929 void HeapRegionRemSet::reset_for_par_iteration() {
930 _iter_state = Unclaimed;
931 _iter_claimed = 0;
932 // It's good to check this to make sure that the two methods are in sync.
933 assert(verify_ready_for_par_iteration(), "post-condition");
934 }
936 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
937 BitMap* region_bm, BitMap* card_bm) {
938 _other_regions.scrub(ctbs, region_bm, card_bm);
939 }
941 // Code roots support
942 //
943 // The code root set is protected by two separate locking schemes
944 // When at safepoint the per-hrrs lock must be held during modifications
945 // except when doing a full gc.
946 // When not at safepoint the CodeCache_lock must be held during modifications.
947 // When concurrent readers access the contains() function
948 // (during the evacuation phase) no removals are allowed.
950 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
951 assert(nm != NULL, "sanity");
952 // Optimistic unlocked contains-check
953 if (!_code_roots.contains(nm)) {
954 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag);
955 add_strong_code_root_locked(nm);
956 }
957 }
959 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) {
960 assert(nm != NULL, "sanity");
961 _code_roots.add(nm);
962 }
964 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
965 assert(nm != NULL, "sanity");
966 assert_locked_or_safepoint(CodeCache_lock);
968 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag);
969 _code_roots.remove(nm);
971 // Check that there were no duplicates
972 guarantee(!_code_roots.contains(nm), "duplicate entry found");
973 }
975 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
976 _code_roots.nmethods_do(blk);
977 }
979 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) {
980 _code_roots.clean(hr);
981 }
983 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
984 return _code_roots.mem_size();
985 }
987 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
988 _hrrs(hrrs),
989 _g1h(G1CollectedHeap::heap()),
990 _coarse_map(&hrrs->_other_regions._coarse_map),
991 _bosa(hrrs->bosa()),
992 _is(Sparse),
993 // Set these values so that we increment to the first region.
994 _coarse_cur_region_index(-1),
995 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
996 _cur_card_in_prt(HeapRegion::CardsPerRegion),
997 _fine_cur_prt(NULL),
998 _n_yielded_coarse(0),
999 _n_yielded_fine(0),
1000 _n_yielded_sparse(0),
1001 _sparse_iter(&hrrs->_other_regions._sparse_table) {}
1003 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
1004 if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
1005 // Go to the next card.
1006 _coarse_cur_region_cur_card++;
1007 // Was the last the last card in the current region?
1008 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
1009 // Yes: find the next region. This may leave _coarse_cur_region_index
1010 // Set to the last index, in which case there are no more coarse
1011 // regions.
1012 _coarse_cur_region_index =
1013 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
1014 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
1015 _coarse_cur_region_cur_card = 0;
1016 HeapWord* r_bot =
1017 _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
1018 _cur_region_card_offset = _bosa->index_for(r_bot);
1019 } else {
1020 return false;
1021 }
1022 }
1023 // If we didn't return false above, then we can yield a card.
1024 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
1025 return true;
1026 }
1028 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
1029 if (fine_has_next()) {
1030 _cur_card_in_prt =
1031 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1032 }
1033 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) {
1034 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for
1035 // the remembered set.
1036 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) {
1037 return false;
1038 }
1039 PerRegionTable* next_prt = _fine_cur_prt->next();
1040 switch_to_prt(next_prt);
1041 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1042 }
1044 card_index = _cur_region_card_offset + _cur_card_in_prt;
1045 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion,
1046 err_msg("Card index "SIZE_FORMAT" must be within the region", _cur_card_in_prt));
1047 return true;
1048 }
1050 bool HeapRegionRemSetIterator::fine_has_next() {
1051 return _cur_card_in_prt != HeapRegion::CardsPerRegion;
1052 }
1054 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) {
1055 assert(prt != NULL, "Cannot switch to NULL prt");
1056 _fine_cur_prt = prt;
1058 HeapWord* r_bot = _fine_cur_prt->hr()->bottom();
1059 _cur_region_card_offset = _bosa->index_for(r_bot);
1061 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1.
1062 // To avoid special-casing this start case, and not miss the first bitmap
1063 // entry, initialize _cur_region_cur_card with -1 instead of 0.
1064 _cur_card_in_prt = (size_t)-1;
1065 }
1067 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
1068 switch (_is) {
1069 case Sparse: {
1070 if (_sparse_iter.has_next(card_index)) {
1071 _n_yielded_sparse++;
1072 return true;
1073 }
1074 // Otherwise, deliberate fall-through
1075 _is = Fine;
1076 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts;
1077 if (initial_fine_prt != NULL) {
1078 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts);
1079 }
1080 }
1081 case Fine:
1082 if (fine_has_next(card_index)) {
1083 _n_yielded_fine++;
1084 return true;
1085 }
1086 // Otherwise, deliberate fall-through
1087 _is = Coarse;
1088 case Coarse:
1089 if (coarse_has_next(card_index)) {
1090 _n_yielded_coarse++;
1091 return true;
1092 }
1093 // Otherwise...
1094 break;
1095 }
1096 assert(ParallelGCThreads > 1 ||
1097 n_yielded() == _hrrs->occupied(),
1098 "Should have yielded all the cards in the rem set "
1099 "(in the non-par case).");
1100 return false;
1101 }
1105 OopOrNarrowOopStar* HeapRegionRemSet::_recorded_oops = NULL;
1106 HeapWord** HeapRegionRemSet::_recorded_cards = NULL;
1107 HeapRegion** HeapRegionRemSet::_recorded_regions = NULL;
1108 int HeapRegionRemSet::_n_recorded = 0;
1110 HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
1111 int* HeapRegionRemSet::_recorded_event_index = NULL;
1112 int HeapRegionRemSet::_n_recorded_events = 0;
1114 void HeapRegionRemSet::record(HeapRegion* hr, OopOrNarrowOopStar f) {
1115 if (_recorded_oops == NULL) {
1116 assert(_n_recorded == 0
1117 && _recorded_cards == NULL
1118 && _recorded_regions == NULL,
1119 "Inv");
1120 _recorded_oops = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
1121 _recorded_cards = NEW_C_HEAP_ARRAY(HeapWord*, MaxRecorded, mtGC);
1122 _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*, MaxRecorded, mtGC);
1123 }
1124 if (_n_recorded == MaxRecorded) {
1125 gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
1126 } else {
1127 _recorded_cards[_n_recorded] =
1128 (HeapWord*)align_size_down(uintptr_t(f),
1129 CardTableModRefBS::card_size);
1130 _recorded_oops[_n_recorded] = f;
1131 _recorded_regions[_n_recorded] = hr;
1132 _n_recorded++;
1133 }
1134 }
1136 void HeapRegionRemSet::record_event(Event evnt) {
1137 if (!G1RecordHRRSEvents) return;
1139 if (_recorded_events == NULL) {
1140 assert(_n_recorded_events == 0
1141 && _recorded_event_index == NULL,
1142 "Inv");
1143 _recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents, mtGC);
1144 _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
1145 }
1146 if (_n_recorded_events == MaxRecordedEvents) {
1147 gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
1148 } else {
1149 _recorded_events[_n_recorded_events] = evnt;
1150 _recorded_event_index[_n_recorded_events] = _n_recorded;
1151 _n_recorded_events++;
1152 }
1153 }
1155 void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
1156 switch (evnt) {
1157 case Event_EvacStart:
1158 str->print("Evac Start");
1159 break;
1160 case Event_EvacEnd:
1161 str->print("Evac End");
1162 break;
1163 case Event_RSUpdateEnd:
1164 str->print("RS Update End");
1165 break;
1166 }
1167 }
1169 void HeapRegionRemSet::print_recorded() {
1170 int cur_evnt = 0;
1171 Event cur_evnt_kind;
1172 int cur_evnt_ind = 0;
1173 if (_n_recorded_events > 0) {
1174 cur_evnt_kind = _recorded_events[cur_evnt];
1175 cur_evnt_ind = _recorded_event_index[cur_evnt];
1176 }
1178 for (int i = 0; i < _n_recorded; i++) {
1179 while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
1180 gclog_or_tty->print("Event: ");
1181 print_event(gclog_or_tty, cur_evnt_kind);
1182 gclog_or_tty->cr();
1183 cur_evnt++;
1184 if (cur_evnt < MaxRecordedEvents) {
1185 cur_evnt_kind = _recorded_events[cur_evnt];
1186 cur_evnt_ind = _recorded_event_index[cur_evnt];
1187 }
1188 }
1189 gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
1190 " for ref " PTR_FORMAT ".\n",
1191 _recorded_cards[i], _recorded_regions[i]->bottom(),
1192 _recorded_oops[i]);
1193 }
1194 }
1196 void HeapRegionRemSet::reset_for_cleanup_tasks() {
1197 SparsePRT::reset_for_cleanup_tasks();
1198 }
1200 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
1201 _other_regions.do_cleanup_work(hrrs_cleanup_task);
1202 }
1204 void
1205 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
1206 SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
1207 }
1209 #ifndef PRODUCT
1210 void PerRegionTable::test_fl_mem_size() {
1211 PerRegionTable* dummy = alloc(NULL);
1213 size_t min_prt_size = sizeof(void*) + dummy->bm()->size_in_words() * HeapWordSize;
1214 assert(dummy->mem_size() > min_prt_size,
1215 err_msg("PerRegionTable memory usage is suspiciously small, only has "SIZE_FORMAT" bytes. "
1216 "Should be at least "SIZE_FORMAT" bytes.", dummy->mem_size(), min_prt_size));
1217 free(dummy);
1218 guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
1219 // try to reset the state
1220 _free_list = NULL;
1221 delete dummy;
1222 }
1224 void HeapRegionRemSet::test_prt() {
1225 PerRegionTable::test_fl_mem_size();
1226 }
1228 void HeapRegionRemSet::test() {
1229 os::sleep(Thread::current(), (jlong)5000, false);
1230 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1232 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
1233 // hash bucket.
1234 HeapRegion* hr0 = g1h->region_at(0);
1235 HeapRegion* hr1 = g1h->region_at(1);
1236 HeapRegion* hr2 = g1h->region_at(5);
1237 HeapRegion* hr3 = g1h->region_at(6);
1238 HeapRegion* hr4 = g1h->region_at(7);
1239 HeapRegion* hr5 = g1h->region_at(8);
1241 HeapWord* hr1_start = hr1->bottom();
1242 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
1243 HeapWord* hr1_last = hr1->end() - 1;
1245 HeapWord* hr2_start = hr2->bottom();
1246 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
1247 HeapWord* hr2_last = hr2->end() - 1;
1249 HeapWord* hr3_start = hr3->bottom();
1250 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
1251 HeapWord* hr3_last = hr3->end() - 1;
1253 HeapRegionRemSet* hrrs = hr0->rem_set();
1255 // Make three references from region 0x101...
1256 hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
1257 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
1258 hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
1260 hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
1261 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
1262 hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
1264 hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
1265 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
1266 hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
1268 // Now cause a coarsening.
1269 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
1270 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
1272 // Now, does iteration yield these three?
1273 HeapRegionRemSetIterator iter(hrrs);
1274 size_t sum = 0;
1275 size_t card_index;
1276 while (iter.has_next(card_index)) {
1277 HeapWord* card_start =
1278 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
1279 gclog_or_tty->print_cr(" Card " PTR_FORMAT ".", card_start);
1280 sum++;
1281 }
1282 guarantee(sum == 11 - 3 + 2048, "Failure");
1283 guarantee(sum == hrrs->occupied(), "Failure");
1284 }
1285 #endif