1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/concurrentG1Refine.hpp"
27 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/heapRegionManager.inline.hpp"
30 #include "gc/g1/heapRegionRemSet.hpp"
31 #include "gc/shared/space.inline.hpp"
32 #include "memory/allocation.hpp"
33 #include "memory/padded.inline.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "runtime/atomic.inline.hpp"
36 #include "utilities/bitMap.inline.hpp"
37 #include "utilities/globalDefinitions.hpp"
38 #include "utilities/growableArray.hpp"
39
40 class PerRegionTable: public CHeapObj<mtGC> {
41 friend class OtherRegionsTable;
42 friend class HeapRegionRemSetIterator;
43
44 HeapRegion* _hr;
45 BitMap _bm;
46 jint _occupied;
47
48 // next pointer for free/allocated 'all' list
49 PerRegionTable* _next;
50
51 // prev pointer for the allocated 'all' list
52 PerRegionTable* _prev;
53
54 // next pointer in collision list
55 PerRegionTable * _collision_list_next;
56
57 // Global free list of PRTs
58 static PerRegionTable* _free_list;
59
60 protected:
61 // We need access in order to union things into the base table.
62 BitMap* bm() { return &_bm; }
63
64 void recount_occupied() {
65 _occupied = (jint) bm()->count_one_bits();
66 }
67
68 PerRegionTable(HeapRegion* hr) :
69 _hr(hr),
70 _occupied(0),
71 _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
72 _collision_list_next(NULL), _next(NULL), _prev(NULL)
73 {}
74
75 void add_card_work(CardIdx_t from_card, bool par) {
76 if (!_bm.at(from_card)) {
77 if (par) {
78 if (_bm.par_at_put(from_card, 1)) {
79 Atomic::inc(&_occupied);
80 }
81 } else {
82 _bm.at_put(from_card, 1);
83 _occupied++;
84 }
85 }
86 }
87
88 void add_reference_work(OopOrNarrowOopStar from, bool par) {
89 // Must make this robust in case "from" is not in "_hr", because of
90 // concurrency.
91
92 HeapRegion* loc_hr = hr();
93 // If the test below fails, then this table was reused concurrently
94 // with this operation. This is OK, since the old table was coarsened,
95 // and adding a bit to the new table is never incorrect.
96 // If the table used to belong to a continues humongous region and is
97 // now reused for the corresponding start humongous region, we need to
98 // make sure that we detect this. Thus, we call is_in_reserved_raw()
99 // instead of just is_in_reserved() here.
100 if (loc_hr->is_in_reserved(from)) {
101 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
102 CardIdx_t from_card = (CardIdx_t)
103 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
104
105 assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
106 "Must be in range.");
107 add_card_work(from_card, par);
108 }
109 }
110
111 public:
112
113 HeapRegion* hr() const { return _hr; }
114
115 jint occupied() const {
116 // Overkill, but if we ever need it...
117 // guarantee(_occupied == _bm.count_one_bits(), "Check");
118 return _occupied;
119 }
120
121 void init(HeapRegion* hr, bool clear_links_to_all_list) {
122 if (clear_links_to_all_list) {
123 set_next(NULL);
124 set_prev(NULL);
125 }
126 _hr = hr;
127 _collision_list_next = NULL;
128 _occupied = 0;
129 _bm.clear();
130 }
131
132 void add_reference(OopOrNarrowOopStar from) {
133 add_reference_work(from, /*parallel*/ true);
134 }
135
136 void seq_add_reference(OopOrNarrowOopStar from) {
137 add_reference_work(from, /*parallel*/ false);
138 }
139
140 void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
141 HeapWord* hr_bot = hr()->bottom();
142 size_t hr_first_card_index = ctbs->index_for(hr_bot);
143 bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
144 recount_occupied();
145 }
146
147 void add_card(CardIdx_t from_card_index) {
148 add_card_work(from_card_index, /*parallel*/ true);
149 }
150
151 void seq_add_card(CardIdx_t from_card_index) {
152 add_card_work(from_card_index, /*parallel*/ false);
153 }
154
155 // (Destructively) union the bitmap of the current table into the given
156 // bitmap (which is assumed to be of the same size.)
157 void union_bitmap_into(BitMap* bm) {
158 bm->set_union(_bm);
159 }
160
161 // Mem size in bytes.
162 size_t mem_size() const {
163 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize;
164 }
165
166 // Requires "from" to be in "hr()".
167 bool contains_reference(OopOrNarrowOopStar from) const {
168 assert(hr()->is_in_reserved(from), "Precondition.");
169 size_t card_ind = pointer_delta(from, hr()->bottom(),
170 CardTableModRefBS::card_size);
171 return _bm.at(card_ind);
172 }
173
174 // Bulk-free the PRTs from prt to last, assumes that they are
175 // linked together using their _next field.
176 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
177 while (true) {
178 PerRegionTable* fl = _free_list;
179 last->set_next(fl);
180 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
181 if (res == fl) {
182 return;
183 }
184 }
185 ShouldNotReachHere();
186 }
187
188 static void free(PerRegionTable* prt) {
189 bulk_free(prt, prt);
190 }
191
192 // Returns an initialized PerRegionTable instance.
193 static PerRegionTable* alloc(HeapRegion* hr) {
194 PerRegionTable* fl = _free_list;
195 while (fl != NULL) {
196 PerRegionTable* nxt = fl->next();
197 PerRegionTable* res =
198 (PerRegionTable*)
199 Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
200 if (res == fl) {
201 fl->init(hr, true);
202 return fl;
203 } else {
204 fl = _free_list;
205 }
206 }
207 assert(fl == NULL, "Loop condition.");
208 return new PerRegionTable(hr);
209 }
210
211 PerRegionTable* next() const { return _next; }
212 void set_next(PerRegionTable* next) { _next = next; }
213 PerRegionTable* prev() const { return _prev; }
214 void set_prev(PerRegionTable* prev) { _prev = prev; }
215
216 // Accessor and Modification routines for the pointer for the
217 // singly linked collision list that links the PRTs within the
218 // OtherRegionsTable::_fine_grain_regions hash table.
219 //
220 // It might be useful to also make the collision list doubly linked
221 // to avoid iteration over the collisions list during scrubbing/deletion.
222 // OTOH there might not be many collisions.
223
224 PerRegionTable* collision_list_next() const {
225 return _collision_list_next;
226 }
227
228 void set_collision_list_next(PerRegionTable* next) {
229 _collision_list_next = next;
230 }
231
232 PerRegionTable** collision_list_next_addr() {
233 return &_collision_list_next;
234 }
235
236 static size_t fl_mem_size() {
237 PerRegionTable* cur = _free_list;
238 size_t res = 0;
239 while (cur != NULL) {
240 res += cur->mem_size();
241 cur = cur->next();
242 }
243 return res;
244 }
245
246 static void test_fl_mem_size();
247 };
248
249 PerRegionTable* PerRegionTable::_free_list = NULL;
250
251 size_t OtherRegionsTable::_max_fine_entries = 0;
252 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
253 size_t OtherRegionsTable::_fine_eviction_stride = 0;
254 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
255
256 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
257 _g1h(G1CollectedHeap::heap()),
258 _hr(hr), _m(m),
259 _coarse_map(G1CollectedHeap::heap()->max_regions(),
260 false /* in-resource-area */),
261 _fine_grain_regions(NULL),
262 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
263 _n_fine_entries(0), _n_coarse_entries(0),
264 _fine_eviction_start(0),
265 _sparse_table(hr)
266 {
267 typedef PerRegionTable* PerRegionTablePtr;
268
269 if (_max_fine_entries == 0) {
270 assert(_mod_max_fine_entries_mask == 0, "Both or none.");
271 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
272 _max_fine_entries = (size_t)1 << max_entries_log;
273 _mod_max_fine_entries_mask = _max_fine_entries - 1;
274
275 assert(_fine_eviction_sample_size == 0
276 && _fine_eviction_stride == 0, "All init at same time.");
277 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
278 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
279 }
280
281 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
282 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
283
284 if (_fine_grain_regions == NULL) {
285 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
286 "Failed to allocate _fine_grain_entries.");
287 }
288
289 for (size_t i = 0; i < _max_fine_entries; i++) {
290 _fine_grain_regions[i] = NULL;
291 }
292 }
293
294 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
295 // We always append to the beginning of the list for convenience;
296 // the order of entries in this list does not matter.
297 if (_first_all_fine_prts != NULL) {
298 assert(_first_all_fine_prts->prev() == NULL, "invariant");
299 _first_all_fine_prts->set_prev(prt);
300 prt->set_next(_first_all_fine_prts);
301 } else {
302 // this is the first element we insert. Adjust the "last" pointer
303 _last_all_fine_prts = prt;
304 assert(prt->next() == NULL, "just checking");
305 }
306 // the new element is always the first element without a predecessor
307 prt->set_prev(NULL);
308 _first_all_fine_prts = prt;
309
310 assert(prt->prev() == NULL, "just checking");
311 assert(_first_all_fine_prts == prt, "just checking");
312 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
313 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
314 "just checking");
315 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
316 "just checking");
317 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
318 "just checking");
319 }
320
321 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
322 if (prt->prev() != NULL) {
323 assert(_first_all_fine_prts != prt, "just checking");
324 prt->prev()->set_next(prt->next());
325 // removing the last element in the list?
326 if (_last_all_fine_prts == prt) {
327 _last_all_fine_prts = prt->prev();
328 }
329 } else {
330 assert(_first_all_fine_prts == prt, "just checking");
331 _first_all_fine_prts = prt->next();
332 // list is empty now?
333 if (_first_all_fine_prts == NULL) {
334 _last_all_fine_prts = NULL;
335 }
336 }
337
338 if (prt->next() != NULL) {
339 prt->next()->set_prev(prt->prev());
340 }
341
342 prt->set_next(NULL);
343 prt->set_prev(NULL);
344
345 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
346 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
347 "just checking");
348 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
349 "just checking");
350 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
351 "just checking");
352 }
353
354 int** FromCardCache::_cache = NULL;
355 uint FromCardCache::_max_regions = 0;
356 size_t FromCardCache::_static_mem_size = 0;
357
358 void FromCardCache::initialize(uint n_par_rs, uint max_num_regions) {
359 guarantee(_cache == NULL, "Should not call this multiple times");
360
361 _max_regions = max_num_regions;
362 _cache = Padded2DArray<int, mtGC>::create_unfreeable(n_par_rs,
363 _max_regions,
364 &_static_mem_size);
365
366 invalidate(0, _max_regions);
367 }
368
369 void FromCardCache::invalidate(uint start_idx, size_t new_num_regions) {
370 guarantee((size_t)start_idx + new_num_regions <= max_uintx,
371 "Trying to invalidate beyond maximum region, from %u size " SIZE_FORMAT,
372 start_idx, new_num_regions);
373 for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
374 uint end_idx = (start_idx + (uint)new_num_regions);
375 assert(end_idx <= _max_regions, "Must be within max.");
376 for (uint j = start_idx; j < end_idx; j++) {
377 set(i, j, InvalidCard);
378 }
379 }
380 }
381
382 #ifndef PRODUCT
383 void FromCardCache::print(outputStream* out) {
384 for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
385 for (uint j = 0; j < _max_regions; j++) {
386 out->print_cr("_from_card_cache[%u][%u] = %d.",
387 i, j, at(i, j));
388 }
389 }
390 }
391 #endif
392
393 void FromCardCache::clear(uint region_idx) {
394 uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
395 for (uint i = 0; i < num_par_remsets; i++) {
396 set(i, region_idx, InvalidCard);
397 }
398 }
399
400 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) {
401 uint cur_hrm_ind = _hr->hrm_index();
402
403 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
404
405 if (FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) {
406 assert(contains_reference(from), "We just added it!");
407 return;
408 }
409
410 // Note that this may be a continued H region.
411 HeapRegion* from_hr = _g1h->heap_region_containing(from);
412 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index();
413
414 // If the region is already coarsened, return.
415 if (_coarse_map.at(from_hrm_ind)) {
416 assert(contains_reference(from), "We just added it!");
417 return;
418 }
419
420 // Otherwise find a per-region table to add it to.
421 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask;
422 PerRegionTable* prt = find_region_table(ind, from_hr);
423 if (prt == NULL) {
424 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
425 // Confirm that it's really not there...
426 prt = find_region_table(ind, from_hr);
427 if (prt == NULL) {
428
429 uintptr_t from_hr_bot_card_index =
430 uintptr_t(from_hr->bottom())
431 >> CardTableModRefBS::card_shift;
432 CardIdx_t card_index = from_card - from_hr_bot_card_index;
433 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
434 "Must be in range.");
435 if (G1HRRSUseSparseTable &&
436 _sparse_table.add_card(from_hrm_ind, card_index)) {
437 assert(contains_reference_locked(from), "We just added it!");
438 return;
439 }
440
441 if (_n_fine_entries == _max_fine_entries) {
442 prt = delete_region_table();
443 // There is no need to clear the links to the 'all' list here:
444 // prt will be reused immediately, i.e. remain in the 'all' list.
445 prt->init(from_hr, false /* clear_links_to_all_list */);
446 } else {
447 prt = PerRegionTable::alloc(from_hr);
448 link_to_all(prt);
449 }
450
451 PerRegionTable* first_prt = _fine_grain_regions[ind];
452 prt->set_collision_list_next(first_prt);
453 // The assignment into _fine_grain_regions allows the prt to
454 // start being used concurrently. In addition to
455 // collision_list_next which must be visible (else concurrent
456 // parsing of the list, if any, may fail to see other entries),
457 // the content of the prt must be visible (else for instance
458 // some mark bits may not yet seem cleared or a 'later' update
459 // performed by a concurrent thread could be undone when the
460 // zeroing becomes visible). This requires store ordering.
461 OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt);
462 _n_fine_entries++;
463
464 if (G1HRRSUseSparseTable) {
465 // Transfer from sparse to fine-grain.
466 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind);
467 assert(sprt_entry != NULL, "There should have been an entry");
468 for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
469 CardIdx_t c = sprt_entry->card(i);
470 if (c != SparsePRTEntry::NullEntry) {
471 prt->add_card(c);
472 }
473 }
474 // Now we can delete the sparse entry.
475 bool res = _sparse_table.delete_entry(from_hrm_ind);
476 assert(res, "It should have been there.");
477 }
478 }
479 assert(prt != NULL && prt->hr() == from_hr, "consequence");
480 }
481 // Note that we can't assert "prt->hr() == from_hr", because of the
482 // possibility of concurrent reuse. But see head comment of
483 // OtherRegionsTable for why this is OK.
484 assert(prt != NULL, "Inv");
485
486 prt->add_reference(from);
487 assert(contains_reference(from), "We just added it!");
488 }
489
490 PerRegionTable*
491 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
492 assert(ind < _max_fine_entries, "Preconditions.");
493 PerRegionTable* prt = _fine_grain_regions[ind];
494 while (prt != NULL && prt->hr() != hr) {
495 prt = prt->collision_list_next();
496 }
497 // Loop postcondition is the method postcondition.
498 return prt;
499 }
500
501 jint OtherRegionsTable::_n_coarsenings = 0;
502
503 PerRegionTable* OtherRegionsTable::delete_region_table() {
504 assert(_m->owned_by_self(), "Precondition");
505 assert(_n_fine_entries == _max_fine_entries, "Precondition");
506 PerRegionTable* max = NULL;
507 jint max_occ = 0;
508 PerRegionTable** max_prev = NULL;
509 size_t max_ind;
510
511 size_t i = _fine_eviction_start;
512 for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
513 size_t ii = i;
514 // Make sure we get a non-NULL sample.
515 while (_fine_grain_regions[ii] == NULL) {
516 ii++;
517 if (ii == _max_fine_entries) ii = 0;
518 guarantee(ii != i, "We must find one.");
519 }
520 PerRegionTable** prev = &_fine_grain_regions[ii];
521 PerRegionTable* cur = *prev;
522 while (cur != NULL) {
523 jint cur_occ = cur->occupied();
524 if (max == NULL || cur_occ > max_occ) {
525 max = cur;
526 max_prev = prev;
527 max_ind = i;
528 max_occ = cur_occ;
529 }
530 prev = cur->collision_list_next_addr();
531 cur = cur->collision_list_next();
532 }
533 i = i + _fine_eviction_stride;
534 if (i >= _n_fine_entries) i = i - _n_fine_entries;
535 }
536
537 _fine_eviction_start++;
538
539 if (_fine_eviction_start >= _n_fine_entries) {
540 _fine_eviction_start -= _n_fine_entries;
541 }
542
543 guarantee(max != NULL, "Since _n_fine_entries > 0");
544 guarantee(max_prev != NULL, "Since max != NULL.");
545
546 // Set the corresponding coarse bit.
547 size_t max_hrm_index = (size_t) max->hr()->hrm_index();
548 if (!_coarse_map.at(max_hrm_index)) {
549 _coarse_map.at_put(max_hrm_index, true);
550 _n_coarse_entries++;
551 }
552
553 // Unsplice.
554 *max_prev = max->collision_list_next();
555 Atomic::inc(&_n_coarsenings);
556 _n_fine_entries--;
557 return max;
558 }
559
560 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
561 BitMap* region_bm, BitMap* card_bm) {
562 // First eliminated garbage regions from the coarse map.
563 if (G1RSScrubVerbose) {
564 gclog_or_tty->print_cr("Scrubbing region %u:", _hr->hrm_index());
565 }
566
567 assert(_coarse_map.size() == region_bm->size(), "Precondition");
568 if (G1RSScrubVerbose) {
569 gclog_or_tty->print(" Coarse map: before = " SIZE_FORMAT "...",
570 _n_coarse_entries);
571 }
572 _coarse_map.set_intersection(*region_bm);
573 _n_coarse_entries = _coarse_map.count_one_bits();
574 if (G1RSScrubVerbose) {
575 gclog_or_tty->print_cr(" after = " SIZE_FORMAT ".", _n_coarse_entries);
576 }
577
578 // Now do the fine-grained maps.
579 for (size_t i = 0; i < _max_fine_entries; i++) {
580 PerRegionTable* cur = _fine_grain_regions[i];
581 PerRegionTable** prev = &_fine_grain_regions[i];
582 while (cur != NULL) {
583 PerRegionTable* nxt = cur->collision_list_next();
584 // If the entire region is dead, eliminate.
585 if (G1RSScrubVerbose) {
586 gclog_or_tty->print_cr(" For other region %u:",
587 cur->hr()->hrm_index());
588 }
589 if (!region_bm->at((size_t) cur->hr()->hrm_index())) {
590 *prev = nxt;
591 cur->set_collision_list_next(NULL);
592 _n_fine_entries--;
593 if (G1RSScrubVerbose) {
594 gclog_or_tty->print_cr(" deleted via region map.");
595 }
596 unlink_from_all(cur);
597 PerRegionTable::free(cur);
598 } else {
599 // Do fine-grain elimination.
600 if (G1RSScrubVerbose) {
601 gclog_or_tty->print(" occ: before = %4d.", cur->occupied());
602 }
603 cur->scrub(ctbs, card_bm);
604 if (G1RSScrubVerbose) {
605 gclog_or_tty->print_cr(" after = %4d.", cur->occupied());
606 }
607 // Did that empty the table completely?
608 if (cur->occupied() == 0) {
609 *prev = nxt;
610 cur->set_collision_list_next(NULL);
611 _n_fine_entries--;
612 unlink_from_all(cur);
613 PerRegionTable::free(cur);
614 } else {
615 prev = cur->collision_list_next_addr();
616 }
617 }
618 cur = nxt;
619 }
620 }
621 // Since we may have deleted a from_card_cache entry from the RS, clear
622 // the FCC.
623 clear_fcc();
624 }
625
626 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const {
627 if (limit <= (size_t)G1RSetSparseRegionEntries) {
628 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit;
629 } else {
630 // Current uses of this method may only use values less than G1RSetSparseRegionEntries
631 // for the limit. The solution, comparing against occupied() would be too slow
632 // at this time.
633 Unimplemented();
634 return false;
635 }
636 }
637
638 bool OtherRegionsTable::is_empty() const {
639 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL;
640 }
641
642 size_t OtherRegionsTable::occupied() const {
643 size_t sum = occ_fine();
644 sum += occ_sparse();
645 sum += occ_coarse();
646 return sum;
647 }
648
649 size_t OtherRegionsTable::occ_fine() const {
650 size_t sum = 0;
651
652 size_t num = 0;
653 PerRegionTable * cur = _first_all_fine_prts;
654 while (cur != NULL) {
655 sum += cur->occupied();
656 cur = cur->next();
657 num++;
658 }
659 guarantee(num == _n_fine_entries, "just checking");
660 return sum;
661 }
662
663 size_t OtherRegionsTable::occ_coarse() const {
664 return (_n_coarse_entries * HeapRegion::CardsPerRegion);
665 }
666
667 size_t OtherRegionsTable::occ_sparse() const {
668 return _sparse_table.occupied();
669 }
670
671 size_t OtherRegionsTable::mem_size() const {
672 size_t sum = 0;
673 // all PRTs are of the same size so it is sufficient to query only one of them.
674 if (_first_all_fine_prts != NULL) {
675 assert(_last_all_fine_prts != NULL &&
676 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
677 sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
678 }
679 sum += (sizeof(PerRegionTable*) * _max_fine_entries);
680 sum += (_coarse_map.size_in_words() * HeapWordSize);
681 sum += (_sparse_table.mem_size());
682 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above.
683 return sum;
684 }
685
686 size_t OtherRegionsTable::static_mem_size() {
687 return FromCardCache::static_mem_size();
688 }
689
690 size_t OtherRegionsTable::fl_mem_size() {
691 return PerRegionTable::fl_mem_size();
692 }
693
694 void OtherRegionsTable::clear_fcc() {
695 FromCardCache::clear(_hr->hrm_index());
696 }
697
698 void OtherRegionsTable::clear() {
699 // if there are no entries, skip this step
700 if (_first_all_fine_prts != NULL) {
701 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
702 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
703 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
704 } else {
705 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
706 }
707
708 _first_all_fine_prts = _last_all_fine_prts = NULL;
709 _sparse_table.clear();
710 _coarse_map.clear();
711 _n_fine_entries = 0;
712 _n_coarse_entries = 0;
713
714 clear_fcc();
715 }
716
717 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
718 // Cast away const in this case.
719 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag);
720 return contains_reference_locked(from);
721 }
722
723 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
724 HeapRegion* hr = _g1h->heap_region_containing(from);
725 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index();
726 // Is this region in the coarse map?
727 if (_coarse_map.at(hr_ind)) return true;
728
729 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
730 hr);
731 if (prt != NULL) {
732 return prt->contains_reference(from);
733
734 } else {
735 uintptr_t from_card =
736 (uintptr_t(from) >> CardTableModRefBS::card_shift);
737 uintptr_t hr_bot_card_index =
738 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
739 assert(from_card >= hr_bot_card_index, "Inv");
740 CardIdx_t card_index = from_card - hr_bot_card_index;
741 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
742 "Must be in range.");
743 return _sparse_table.contains_card(hr_ind, card_index);
744 }
745 }
746
747 void
748 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
749 _sparse_table.do_cleanup_work(hrrs_cleanup_task);
750 }
751
752 // Determines how many threads can add records to an rset in parallel.
753 // This can be done by either mutator threads together with the
754 // concurrent refinement threads or GC threads.
755 uint HeapRegionRemSet::num_par_rem_sets() {
756 return MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), ParallelGCThreads);
757 }
758
759 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
760 HeapRegion* hr)
761 : _bosa(bosa),
762 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never),
763 _code_roots(), _other_regions(hr, &_m), _iter_state(Unclaimed), _iter_claimed(0) {
764 reset_for_par_iteration();
765 }
766
767 void HeapRegionRemSet::setup_remset_size() {
768 // Setup sparse and fine-grain tables sizes.
769 // table_size = base * (log(region_size / 1M) + 1)
770 const int LOG_M = 20;
771 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
772 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
773 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
774 }
775 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
776 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
777 }
778 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
779 }
780
781 bool HeapRegionRemSet::claim_iter() {
782 if (_iter_state != Unclaimed) return false;
783 jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
784 return (res == Unclaimed);
785 }
786
787 void HeapRegionRemSet::set_iter_complete() {
788 _iter_state = Complete;
789 }
790
791 bool HeapRegionRemSet::iter_is_complete() {
792 return _iter_state == Complete;
793 }
794
795 #ifndef PRODUCT
796 void HeapRegionRemSet::print() {
797 HeapRegionRemSetIterator iter(this);
798 size_t card_index;
799 while (iter.has_next(card_index)) {
800 HeapWord* card_start =
801 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
802 gclog_or_tty->print_cr(" Card " PTR_FORMAT, p2i(card_start));
803 }
804 if (iter.n_yielded() != occupied()) {
805 gclog_or_tty->print_cr("Yielded disagrees with occupied:");
806 gclog_or_tty->print_cr(" " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6)
807 " coarse, " SIZE_FORMAT_W(6) " fine).",
808 iter.n_yielded(),
809 iter.n_yielded_coarse(), iter.n_yielded_fine());
810 gclog_or_tty->print_cr(" " SIZE_FORMAT_W(6) " occ (" SIZE_FORMAT_W(6)
811 " coarse, " SIZE_FORMAT_W(6) " fine).",
812 occupied(), occ_coarse(), occ_fine());
813 }
814 guarantee(iter.n_yielded() == occupied(),
815 "We should have yielded all the represented cards.");
816 }
817 #endif
818
819 void HeapRegionRemSet::cleanup() {
820 SparsePRT::cleanup_all();
821 }
822
823 void HeapRegionRemSet::clear() {
824 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
825 clear_locked();
826 }
827
828 void HeapRegionRemSet::clear_locked() {
829 _code_roots.clear();
830 _other_regions.clear();
831 assert(occupied_locked() == 0, "Should be clear.");
832 reset_for_par_iteration();
833 }
834
835 void HeapRegionRemSet::reset_for_par_iteration() {
836 _iter_state = Unclaimed;
837 _iter_claimed = 0;
838 // It's good to check this to make sure that the two methods are in sync.
839 assert(verify_ready_for_par_iteration(), "post-condition");
840 }
841
842 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
843 BitMap* region_bm, BitMap* card_bm) {
844 _other_regions.scrub(ctbs, region_bm, card_bm);
845 }
846
847 // Code roots support
848 //
849 // The code root set is protected by two separate locking schemes
850 // When at safepoint the per-hrrs lock must be held during modifications
851 // except when doing a full gc.
852 // When not at safepoint the CodeCache_lock must be held during modifications.
853 // When concurrent readers access the contains() function
854 // (during the evacuation phase) no removals are allowed.
855
856 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
857 assert(nm != NULL, "sanity");
858 // Optimistic unlocked contains-check
859 if (!_code_roots.contains(nm)) {
860 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag);
861 add_strong_code_root_locked(nm);
862 }
863 }
864
865 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) {
866 assert(nm != NULL, "sanity");
867 _code_roots.add(nm);
868 }
869
870 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
871 assert(nm != NULL, "sanity");
872 assert_locked_or_safepoint(CodeCache_lock);
873
874 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag);
875 _code_roots.remove(nm);
876
877 // Check that there were no duplicates
878 guarantee(!_code_roots.contains(nm), "duplicate entry found");
879 }
880
881 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
882 _code_roots.nmethods_do(blk);
883 }
884
885 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) {
886 _code_roots.clean(hr);
887 }
888
889 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
890 return _code_roots.mem_size();
891 }
892
893 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
894 _hrrs(hrrs),
895 _g1h(G1CollectedHeap::heap()),
896 _coarse_map(&hrrs->_other_regions._coarse_map),
897 _bosa(hrrs->_bosa),
898 _is(Sparse),
899 // Set these values so that we increment to the first region.
900 _coarse_cur_region_index(-1),
901 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
902 _cur_card_in_prt(HeapRegion::CardsPerRegion),
903 _fine_cur_prt(NULL),
904 _n_yielded_coarse(0),
905 _n_yielded_fine(0),
906 _n_yielded_sparse(0),
907 _sparse_iter(&hrrs->_other_regions._sparse_table) {}
908
909 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
910 if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
911 // Go to the next card.
912 _coarse_cur_region_cur_card++;
913 // Was the last the last card in the current region?
914 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
915 // Yes: find the next region. This may leave _coarse_cur_region_index
916 // Set to the last index, in which case there are no more coarse
917 // regions.
918 _coarse_cur_region_index =
919 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
920 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
921 _coarse_cur_region_cur_card = 0;
922 HeapWord* r_bot =
923 _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
924 _cur_region_card_offset = _bosa->index_for(r_bot);
925 } else {
926 return false;
927 }
928 }
929 // If we didn't return false above, then we can yield a card.
930 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
931 return true;
932 }
933
934 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
935 if (fine_has_next()) {
936 _cur_card_in_prt =
937 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
938 }
939 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) {
940 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for
941 // the remembered set.
942 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) {
943 return false;
944 }
945 PerRegionTable* next_prt = _fine_cur_prt->next();
946 switch_to_prt(next_prt);
947 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
948 }
949
950 card_index = _cur_region_card_offset + _cur_card_in_prt;
951 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion,
952 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt);
953 return true;
954 }
955
956 bool HeapRegionRemSetIterator::fine_has_next() {
957 return _cur_card_in_prt != HeapRegion::CardsPerRegion;
958 }
959
960 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) {
961 assert(prt != NULL, "Cannot switch to NULL prt");
962 _fine_cur_prt = prt;
963
964 HeapWord* r_bot = _fine_cur_prt->hr()->bottom();
965 _cur_region_card_offset = _bosa->index_for(r_bot);
966
967 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1.
968 // To avoid special-casing this start case, and not miss the first bitmap
969 // entry, initialize _cur_region_cur_card with -1 instead of 0.
970 _cur_card_in_prt = (size_t)-1;
971 }
972
973 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
974 switch (_is) {
975 case Sparse: {
976 if (_sparse_iter.has_next(card_index)) {
977 _n_yielded_sparse++;
978 return true;
979 }
980 // Otherwise, deliberate fall-through
981 _is = Fine;
982 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts;
983 if (initial_fine_prt != NULL) {
984 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts);
985 }
986 }
987 case Fine:
988 if (fine_has_next(card_index)) {
989 _n_yielded_fine++;
990 return true;
991 }
992 // Otherwise, deliberate fall-through
993 _is = Coarse;
994 case Coarse:
995 if (coarse_has_next(card_index)) {
996 _n_yielded_coarse++;
997 return true;
998 }
999 // Otherwise...
1000 break;
1001 }
1002 assert(ParallelGCThreads > 1 ||
1003 n_yielded() == _hrrs->occupied(),
1004 "Should have yielded all the cards in the rem set "
1005 "(in the non-par case).");
1006 return false;
1007 }
1008
1009 void HeapRegionRemSet::reset_for_cleanup_tasks() {
1010 SparsePRT::reset_for_cleanup_tasks();
1011 }
1012
1013 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
1014 _other_regions.do_cleanup_work(hrrs_cleanup_task);
1015 }
1016
1017 void
1018 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
1019 SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
1020 }
1021
1022 #ifndef PRODUCT
1023 void HeapRegionRemSet::test() {
1024 os::sleep(Thread::current(), (jlong)5000, false);
1025 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1026
1027 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
1028 // hash bucket.
1029 HeapRegion* hr0 = g1h->region_at(0);
1030 HeapRegion* hr1 = g1h->region_at(1);
1031 HeapRegion* hr2 = g1h->region_at(5);
1032 HeapRegion* hr3 = g1h->region_at(6);
1033 HeapRegion* hr4 = g1h->region_at(7);
1034 HeapRegion* hr5 = g1h->region_at(8);
1035
1036 HeapWord* hr1_start = hr1->bottom();
1037 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
1038 HeapWord* hr1_last = hr1->end() - 1;
1039
1040 HeapWord* hr2_start = hr2->bottom();
1041 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
1042 HeapWord* hr2_last = hr2->end() - 1;
1043
1044 HeapWord* hr3_start = hr3->bottom();
1045 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
1046 HeapWord* hr3_last = hr3->end() - 1;
1047
1048 HeapRegionRemSet* hrrs = hr0->rem_set();
1049
1050 // Make three references from region 0x101...
1051 hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
1052 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
1053 hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
1054
1055 hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
1056 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
1057 hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
1058
1059 hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
1060 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
1061 hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
1062
1063 // Now cause a coarsening.
1064 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
1065 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
1066
1067 // Now, does iteration yield these three?
1068 HeapRegionRemSetIterator iter(hrrs);
1069 size_t sum = 0;
1070 size_t card_index;
1071 while (iter.has_next(card_index)) {
1072 HeapWord* card_start =
1073 G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
1074 gclog_or_tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start));
1075 sum++;
1076 }
1077 guarantee(sum == 11 - 3 + 2048, "Failure");
1078 guarantee(sum == hrrs->occupied(), "Failure");
1079 }
1080 #endif