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
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/g1CardLiveData.inline.hpp"
30 #include "gc/g1/heapRegionManager.inline.hpp"
31 #include "gc/g1/heapRegionRemSet.hpp"
32 #include "gc/shared/space.inline.hpp"
33 #include "memory/allocation.hpp"
34 #include "memory/padded.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "runtime/atomic.hpp"
37 #include "utilities/bitMap.inline.hpp"
38 #include "utilities/globalDefinitions.hpp"
39 #include "utilities/growableArray.hpp"
40
41 class PerRegionTable: public CHeapObj<mtGC> {
42 friend class OtherRegionsTable;
43 friend class HeapRegionRemSetIterator;
44
45 HeapRegion* _hr;
46 CHeapBitMap _bm;
47 jint _occupied;
48
49 // next pointer for free/allocated 'all' list
50 PerRegionTable* _next;
51
52 // prev pointer for the allocated 'all' list
53 PerRegionTable* _prev;
54
55 // next pointer in collision list
56 PerRegionTable * _collision_list_next;
57
58 // Global free list of PRTs
59 static PerRegionTable* _free_list;
60
61 protected:
62 // We need access in order to union things into the base table.
63 BitMap* bm() { return &_bm; }
64
65 void recount_occupied() {
66 _occupied = (jint) bm()->count_one_bits();
67 }
68
69 PerRegionTable(HeapRegion* hr) :
70 _hr(hr),
71 _occupied(0),
72 _bm(HeapRegion::CardsPerRegion),
73 _collision_list_next(NULL), _next(NULL), _prev(NULL)
74 {}
75
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 }
88
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.
92
93 HeapRegion* loc_hr = hr();
94 // If the test below fails, then this table was reused concurrently
95 // with this operation. This is OK, since the old table was coarsened,
96 // and adding a bit to the new table is never incorrect.
97 // If the table used to belong to a continues humongous region and is
98 // now reused for the corresponding start humongous region, we need to
99 // make sure that we detect this. Thus, we call is_in_reserved_raw()
100 // instead of just is_in_reserved() here.
101 if (loc_hr->is_in_reserved(from)) {
102 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
103 CardIdx_t from_card = (CardIdx_t)
104 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
105
106 assert((size_t)from_card < HeapRegion::CardsPerRegion,
107 "Must be in range.");
108 add_card_work(from_card, par);
109 }
110 }
111
112 public:
113
114 HeapRegion* hr() const {
115 return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr);
116 }
117
118 jint occupied() const {
119 // Overkill, but if we ever need it...
120 // guarantee(_occupied == _bm.count_one_bits(), "Check");
121 return _occupied;
122 }
123
124 void init(HeapRegion* hr, bool clear_links_to_all_list) {
125 if (clear_links_to_all_list) {
126 set_next(NULL);
127 set_prev(NULL);
128 }
129 _collision_list_next = NULL;
130 _occupied = 0;
131 _bm.clear();
132 // Make sure that the bitmap clearing above has been finished before publishing
133 // this PRT to concurrent threads.
134 OrderAccess::release_store_ptr(&_hr, hr);
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(G1CardLiveData* live_data) {
146 live_data->remove_nonlive_cards(hr()->hrm_index(), &_bm);
147 recount_occupied();
148 }
149
150 void add_card(CardIdx_t from_card_index) {
151 add_card_work(from_card_index, /*parallel*/ true);
152 }
153
154 void seq_add_card(CardIdx_t from_card_index) {
155 add_card_work(from_card_index, /*parallel*/ false);
156 }
157
158 // (Destructively) union the bitmap of the current table into the given
159 // bitmap (which is assumed to be of the same size.)
160 void union_bitmap_into(BitMap* bm) {
161 bm->set_union(_bm);
162 }
163
164 // Mem size in bytes.
165 size_t mem_size() const {
166 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize;
167 }
168
169 // Requires "from" to be in "hr()".
170 bool contains_reference(OopOrNarrowOopStar from) const {
171 assert(hr()->is_in_reserved(from), "Precondition.");
172 size_t card_ind = pointer_delta(from, hr()->bottom(),
173 CardTableModRefBS::card_size);
174 return _bm.at(card_ind);
175 }
176
177 // Bulk-free the PRTs from prt to last, assumes that they are
178 // linked together using their _next field.
179 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
180 while (true) {
181 PerRegionTable* fl = _free_list;
182 last->set_next(fl);
183 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
184 if (res == fl) {
185 return;
186 }
187 }
188 ShouldNotReachHere();
189 }
190
191 static void free(PerRegionTable* prt) {
192 bulk_free(prt, prt);
193 }
194
195 // Returns an initialized PerRegionTable instance.
196 static PerRegionTable* alloc(HeapRegion* hr) {
197 PerRegionTable* fl = _free_list;
198 while (fl != NULL) {
199 PerRegionTable* nxt = fl->next();
200 PerRegionTable* res =
201 (PerRegionTable*)
202 Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
203 if (res == fl) {
204 fl->init(hr, true);
205 return fl;
206 } else {
207 fl = _free_list;
208 }
209 }
210 assert(fl == NULL, "Loop condition.");
211 return new PerRegionTable(hr);
212 }
213
214 PerRegionTable* next() const { return _next; }
215 void set_next(PerRegionTable* next) { _next = next; }
216 PerRegionTable* prev() const { return _prev; }
217 void set_prev(PerRegionTable* prev) { _prev = prev; }
218
219 // Accessor and Modification routines for the pointer for the
220 // singly linked collision list that links the PRTs within the
221 // OtherRegionsTable::_fine_grain_regions hash table.
222 //
223 // It might be useful to also make the collision list doubly linked
224 // to avoid iteration over the collisions list during scrubbing/deletion.
225 // OTOH there might not be many collisions.
226
227 PerRegionTable* collision_list_next() const {
228 return _collision_list_next;
229 }
230
231 void set_collision_list_next(PerRegionTable* next) {
232 _collision_list_next = next;
233 }
234
235 PerRegionTable** collision_list_next_addr() {
236 return &_collision_list_next;
237 }
238
239 static size_t fl_mem_size() {
240 PerRegionTable* cur = _free_list;
241 size_t res = 0;
242 while (cur != NULL) {
243 res += cur->mem_size();
244 cur = cur->next();
245 }
246 return res;
247 }
248
249 static void test_fl_mem_size();
250 };
251
252 PerRegionTable* PerRegionTable::_free_list = NULL;
253
254 size_t OtherRegionsTable::_max_fine_entries = 0;
255 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
256 size_t OtherRegionsTable::_fine_eviction_stride = 0;
257 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
258
259 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
260 _g1h(G1CollectedHeap::heap()),
261 _hr(hr), _m(m),
262 _coarse_map(G1CollectedHeap::heap()->max_regions()),
263 _fine_grain_regions(NULL),
264 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
265 _n_fine_entries(0), _n_coarse_entries(0),
266 _fine_eviction_start(0),
267 _sparse_table(hr)
268 {
269 typedef PerRegionTable* PerRegionTablePtr;
270
271 if (_max_fine_entries == 0) {
272 assert(_mod_max_fine_entries_mask == 0, "Both or none.");
273 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
274 _max_fine_entries = (size_t)1 << max_entries_log;
275 _mod_max_fine_entries_mask = _max_fine_entries - 1;
276
277 assert(_fine_eviction_sample_size == 0
278 && _fine_eviction_stride == 0, "All init at same time.");
279 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
280 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
281 }
282
283 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
284 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
285
286 if (_fine_grain_regions == NULL) {
287 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
288 "Failed to allocate _fine_grain_entries.");
289 }
290
291 for (size_t i = 0; i < _max_fine_entries; i++) {
292 _fine_grain_regions[i] = NULL;
293 }
294 }
295
296 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
297 // We always append to the beginning of the list for convenience;
298 // the order of entries in this list does not matter.
299 if (_first_all_fine_prts != NULL) {
300 assert(_first_all_fine_prts->prev() == NULL, "invariant");
301 _first_all_fine_prts->set_prev(prt);
302 prt->set_next(_first_all_fine_prts);
303 } else {
304 // this is the first element we insert. Adjust the "last" pointer
305 _last_all_fine_prts = prt;
306 assert(prt->next() == NULL, "just checking");
307 }
308 // the new element is always the first element without a predecessor
309 prt->set_prev(NULL);
310 _first_all_fine_prts = prt;
311
312 assert(prt->prev() == NULL, "just checking");
313 assert(_first_all_fine_prts == prt, "just checking");
314 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
315 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
316 "just checking");
317 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
318 "just checking");
319 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
320 "just checking");
321 }
322
323 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
324 if (prt->prev() != NULL) {
325 assert(_first_all_fine_prts != prt, "just checking");
326 prt->prev()->set_next(prt->next());
327 // removing the last element in the list?
328 if (_last_all_fine_prts == prt) {
329 _last_all_fine_prts = prt->prev();
330 }
331 } else {
332 assert(_first_all_fine_prts == prt, "just checking");
333 _first_all_fine_prts = prt->next();
334 // list is empty now?
335 if (_first_all_fine_prts == NULL) {
336 _last_all_fine_prts = NULL;
337 }
338 }
339
340 if (prt->next() != NULL) {
341 prt->next()->set_prev(prt->prev());
342 }
343
344 prt->set_next(NULL);
345 prt->set_prev(NULL);
346
347 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
348 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
349 "just checking");
350 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
351 "just checking");
352 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
353 "just checking");
354 }
355
356 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) {
357 uint cur_hrm_ind = _hr->hrm_index();
358
359 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
360
361 if (G1FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) {
362 assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from));
363 return;
364 }
365
366 // Note that this may be a continued H region.
367 HeapRegion* from_hr = _g1h->heap_region_containing(from);
368 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index();
369
370 // If the region is already coarsened, return.
371 if (_coarse_map.at(from_hrm_ind)) {
372 assert(contains_reference(from), "We just found " PTR_FORMAT " in the Coarse table", p2i(from));
373 return;
374 }
375
376 // Otherwise find a per-region table to add it to.
377 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask;
378 PerRegionTable* prt = find_region_table(ind, from_hr);
379 if (prt == NULL) {
380 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
381 // Confirm that it's really not there...
382 prt = find_region_table(ind, from_hr);
383 if (prt == NULL) {
384
385 uintptr_t from_hr_bot_card_index =
386 uintptr_t(from_hr->bottom())
387 >> CardTableModRefBS::card_shift;
388 CardIdx_t card_index = from_card - from_hr_bot_card_index;
389 assert((size_t)card_index < HeapRegion::CardsPerRegion,
390 "Must be in range.");
391 if (G1HRRSUseSparseTable &&
392 _sparse_table.add_card(from_hrm_ind, card_index)) {
393 assert(contains_reference_locked(from), "We just added " PTR_FORMAT " to the Sparse table", p2i(from));
394 return;
395 }
396
397 if (_n_fine_entries == _max_fine_entries) {
398 prt = delete_region_table();
399 // There is no need to clear the links to the 'all' list here:
400 // prt will be reused immediately, i.e. remain in the 'all' list.
401 prt->init(from_hr, false /* clear_links_to_all_list */);
402 } else {
403 prt = PerRegionTable::alloc(from_hr);
404 link_to_all(prt);
405 }
406
407 PerRegionTable* first_prt = _fine_grain_regions[ind];
408 prt->set_collision_list_next(first_prt);
409 // The assignment into _fine_grain_regions allows the prt to
410 // start being used concurrently. In addition to
411 // collision_list_next which must be visible (else concurrent
412 // parsing of the list, if any, may fail to see other entries),
413 // the content of the prt must be visible (else for instance
414 // some mark bits may not yet seem cleared or a 'later' update
415 // performed by a concurrent thread could be undone when the
416 // zeroing becomes visible). This requires store ordering.
417 OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt);
418 _n_fine_entries++;
419
420 if (G1HRRSUseSparseTable) {
421 // Transfer from sparse to fine-grain.
422 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind);
423 assert(sprt_entry != NULL, "There should have been an entry");
424 for (int i = 0; i < sprt_entry->num_valid_cards(); i++) {
425 CardIdx_t c = sprt_entry->card(i);
426 prt->add_card(c);
427 }
428 // Now we can delete the sparse entry.
429 bool res = _sparse_table.delete_entry(from_hrm_ind);
430 assert(res, "It should have been there.");
431 }
432 }
433 assert(prt != NULL && prt->hr() == from_hr, "consequence");
434 }
435 // Note that we can't assert "prt->hr() == from_hr", because of the
436 // possibility of concurrent reuse. But see head comment of
437 // OtherRegionsTable for why this is OK.
438 assert(prt != NULL, "Inv");
439
440 prt->add_reference(from);
441 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from));
442 }
443
444 PerRegionTable*
445 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
446 assert(ind < _max_fine_entries, "Preconditions.");
447 PerRegionTable* prt = _fine_grain_regions[ind];
448 while (prt != NULL && prt->hr() != hr) {
449 prt = prt->collision_list_next();
450 }
451 // Loop postcondition is the method postcondition.
452 return prt;
453 }
454
455 jint OtherRegionsTable::_n_coarsenings = 0;
456
457 PerRegionTable* OtherRegionsTable::delete_region_table() {
458 assert(_m->owned_by_self(), "Precondition");
459 assert(_n_fine_entries == _max_fine_entries, "Precondition");
460 PerRegionTable* max = NULL;
461 jint max_occ = 0;
462 PerRegionTable** max_prev = NULL;
463 size_t max_ind;
464
465 size_t i = _fine_eviction_start;
466 for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
467 size_t ii = i;
468 // Make sure we get a non-NULL sample.
469 while (_fine_grain_regions[ii] == NULL) {
470 ii++;
471 if (ii == _max_fine_entries) ii = 0;
472 guarantee(ii != i, "We must find one.");
473 }
474 PerRegionTable** prev = &_fine_grain_regions[ii];
475 PerRegionTable* cur = *prev;
476 while (cur != NULL) {
477 jint cur_occ = cur->occupied();
478 if (max == NULL || cur_occ > max_occ) {
479 max = cur;
480 max_prev = prev;
481 max_ind = i;
482 max_occ = cur_occ;
483 }
484 prev = cur->collision_list_next_addr();
485 cur = cur->collision_list_next();
486 }
487 i = i + _fine_eviction_stride;
488 if (i >= _n_fine_entries) i = i - _n_fine_entries;
489 }
490
491 _fine_eviction_start++;
492
493 if (_fine_eviction_start >= _n_fine_entries) {
494 _fine_eviction_start -= _n_fine_entries;
495 }
496
497 guarantee(max != NULL, "Since _n_fine_entries > 0");
498 guarantee(max_prev != NULL, "Since max != NULL.");
499
500 // Set the corresponding coarse bit.
501 size_t max_hrm_index = (size_t) max->hr()->hrm_index();
502 if (!_coarse_map.at(max_hrm_index)) {
503 _coarse_map.at_put(max_hrm_index, true);
504 _n_coarse_entries++;
505 }
506
507 // Unsplice.
508 *max_prev = max->collision_list_next();
509 Atomic::inc(&_n_coarsenings);
510 _n_fine_entries--;
511 return max;
512 }
513
514 void OtherRegionsTable::scrub(G1CardLiveData* live_data) {
515 // First eliminated garbage regions from the coarse map.
516 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index());
517
518 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries);
519 if (_n_coarse_entries > 0) {
520 live_data->remove_nonlive_regions(&_coarse_map);
521 _n_coarse_entries = _coarse_map.count_one_bits();
522 }
523 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries);
524
525 // Now do the fine-grained maps.
526 for (size_t i = 0; i < _max_fine_entries; i++) {
527 PerRegionTable* cur = _fine_grain_regions[i];
528 PerRegionTable** prev = &_fine_grain_regions[i];
529 while (cur != NULL) {
530 PerRegionTable* nxt = cur->collision_list_next();
531 // If the entire region is dead, eliminate.
532 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index());
533 if (!live_data->is_region_live(cur->hr()->hrm_index())) {
534 *prev = nxt;
535 cur->set_collision_list_next(NULL);
536 _n_fine_entries--;
537 log_develop_trace(gc, remset, scrub)(" deleted via region map.");
538 unlink_from_all(cur);
539 PerRegionTable::free(cur);
540 } else {
541 // Do fine-grain elimination.
542 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied());
543 cur->scrub(live_data);
544 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied());
545 // Did that empty the table completely?
546 if (cur->occupied() == 0) {
547 *prev = nxt;
548 cur->set_collision_list_next(NULL);
549 _n_fine_entries--;
550 unlink_from_all(cur);
551 PerRegionTable::free(cur);
552 } else {
553 prev = cur->collision_list_next_addr();
554 }
555 }
556 cur = nxt;
557 }
558 }
559 // Since we may have deleted a from_card_cache entry from the RS, clear
560 // the FCC.
561 clear_fcc();
562 }
563
564 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const {
565 if (limit <= (size_t)G1RSetSparseRegionEntries) {
566 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit;
567 } else {
568 // Current uses of this method may only use values less than G1RSetSparseRegionEntries
569 // for the limit. The solution, comparing against occupied() would be too slow
570 // at this time.
571 Unimplemented();
572 return false;
573 }
574 }
575
576 bool OtherRegionsTable::is_empty() const {
577 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL;
578 }
579
580 size_t OtherRegionsTable::occupied() const {
581 size_t sum = occ_fine();
582 sum += occ_sparse();
583 sum += occ_coarse();
584 return sum;
585 }
586
587 size_t OtherRegionsTable::occ_fine() const {
588 size_t sum = 0;
589
590 size_t num = 0;
591 PerRegionTable * cur = _first_all_fine_prts;
592 while (cur != NULL) {
593 sum += cur->occupied();
594 cur = cur->next();
595 num++;
596 }
597 guarantee(num == _n_fine_entries, "just checking");
598 return sum;
599 }
600
601 size_t OtherRegionsTable::occ_coarse() const {
602 return (_n_coarse_entries * HeapRegion::CardsPerRegion);
603 }
604
605 size_t OtherRegionsTable::occ_sparse() const {
606 return _sparse_table.occupied();
607 }
608
609 size_t OtherRegionsTable::mem_size() const {
610 size_t sum = 0;
611 // all PRTs are of the same size so it is sufficient to query only one of them.
612 if (_first_all_fine_prts != NULL) {
613 assert(_last_all_fine_prts != NULL &&
614 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
615 sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
616 }
617 sum += (sizeof(PerRegionTable*) * _max_fine_entries);
618 sum += (_coarse_map.size_in_words() * HeapWordSize);
619 sum += (_sparse_table.mem_size());
620 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above.
621 return sum;
622 }
623
624 size_t OtherRegionsTable::static_mem_size() {
625 return G1FromCardCache::static_mem_size();
626 }
627
628 size_t OtherRegionsTable::fl_mem_size() {
629 return PerRegionTable::fl_mem_size();
630 }
631
632 void OtherRegionsTable::clear_fcc() {
633 G1FromCardCache::clear(_hr->hrm_index());
634 }
635
636 void OtherRegionsTable::clear() {
637 // if there are no entries, skip this step
638 if (_first_all_fine_prts != NULL) {
639 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
640 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
641 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
642 } else {
643 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
644 }
645
646 _first_all_fine_prts = _last_all_fine_prts = NULL;
647 _sparse_table.clear();
648 if (_n_coarse_entries > 0) {
649 _coarse_map.clear();
650 }
651 _n_fine_entries = 0;
652 _n_coarse_entries = 0;
653
654 clear_fcc();
655 }
656
657 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
658 // Cast away const in this case.
659 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag);
660 return contains_reference_locked(from);
661 }
662
663 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
664 HeapRegion* hr = _g1h->heap_region_containing(from);
665 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index();
666 // Is this region in the coarse map?
667 if (_coarse_map.at(hr_ind)) return true;
668
669 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
670 hr);
671 if (prt != NULL) {
672 return prt->contains_reference(from);
673
674 } else {
675 uintptr_t from_card =
676 (uintptr_t(from) >> CardTableModRefBS::card_shift);
677 uintptr_t hr_bot_card_index =
678 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
679 assert(from_card >= hr_bot_card_index, "Inv");
680 CardIdx_t card_index = from_card - hr_bot_card_index;
681 assert((size_t)card_index < HeapRegion::CardsPerRegion,
682 "Must be in range.");
683 return _sparse_table.contains_card(hr_ind, card_index);
684 }
685 }
686
687 void
688 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
689 _sparse_table.do_cleanup_work(hrrs_cleanup_task);
690 }
691
692 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot,
693 HeapRegion* hr)
694 : _bot(bot),
695 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never),
696 _code_roots(),
697 _other_regions(hr, &_m) {
698 }
699
700 void HeapRegionRemSet::setup_remset_size() {
701 // Setup sparse and fine-grain tables sizes.
702 // table_size = base * (log(region_size / 1M) + 1)
703 const int LOG_M = 20;
704 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
705 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
706 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
707 }
708 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
709 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
710 }
711 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
712 }
713
714 #ifndef PRODUCT
715 void HeapRegionRemSet::print() {
716 HeapRegionRemSetIterator iter(this);
717 size_t card_index;
718 while (iter.has_next(card_index)) {
719 HeapWord* card_start = _bot->address_for_index(card_index);
720 tty->print_cr(" Card " PTR_FORMAT, p2i(card_start));
721 }
722 if (iter.n_yielded() != occupied()) {
723 tty->print_cr("Yielded disagrees with occupied:");
724 tty->print_cr(" " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6)
725 " coarse, " SIZE_FORMAT_W(6) " fine).",
726 iter.n_yielded(),
727 iter.n_yielded_coarse(), iter.n_yielded_fine());
728 tty->print_cr(" " SIZE_FORMAT_W(6) " occ (" SIZE_FORMAT_W(6)
729 " coarse, " SIZE_FORMAT_W(6) " fine).",
730 occupied(), occ_coarse(), occ_fine());
731 }
732 guarantee(iter.n_yielded() == occupied(),
733 "We should have yielded all the represented cards.");
734 }
735 #endif
736
737 void HeapRegionRemSet::cleanup() {
738 SparsePRT::cleanup_all();
739 }
740
741 void HeapRegionRemSet::clear() {
742 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
743 clear_locked();
744 }
745
746 void HeapRegionRemSet::clear_locked() {
747 _code_roots.clear();
748 _other_regions.clear();
749 assert(occupied_locked() == 0, "Should be clear.");
750 }
751
752 void HeapRegionRemSet::scrub(G1CardLiveData* live_data) {
753 _other_regions.scrub(live_data);
754 }
755
756 // Code roots support
757 //
758 // The code root set is protected by two separate locking schemes
759 // When at safepoint the per-hrrs lock must be held during modifications
760 // except when doing a full gc.
761 // When not at safepoint the CodeCache_lock must be held during modifications.
762 // When concurrent readers access the contains() function
763 // (during the evacuation phase) no removals are allowed.
764
765 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
766 assert(nm != NULL, "sanity");
767 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()),
768 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s",
769 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()));
770 // Optimistic unlocked contains-check
771 if (!_code_roots.contains(nm)) {
772 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag);
773 add_strong_code_root_locked(nm);
774 }
775 }
776
777 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) {
778 assert(nm != NULL, "sanity");
779 assert((CodeCache_lock->owned_by_self() ||
780 (SafepointSynchronize::is_at_safepoint() &&
781 (_m.owned_by_self() || Thread::current()->is_VM_thread()))),
782 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s",
783 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()),
784 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread()));
785 _code_roots.add(nm);
786 }
787
788 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
789 assert(nm != NULL, "sanity");
790 assert_locked_or_safepoint(CodeCache_lock);
791
792 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag);
793 _code_roots.remove(nm);
794
795 // Check that there were no duplicates
796 guarantee(!_code_roots.contains(nm), "duplicate entry found");
797 }
798
799 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
800 _code_roots.nmethods_do(blk);
801 }
802
803 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) {
804 _code_roots.clean(hr);
805 }
806
807 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
808 return _code_roots.mem_size();
809 }
810
811 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
812 _hrrs(hrrs),
813 _g1h(G1CollectedHeap::heap()),
814 _coarse_map(&hrrs->_other_regions._coarse_map),
815 _bot(hrrs->_bot),
816 _is(Sparse),
817 // Set these values so that we increment to the first region.
818 _coarse_cur_region_index(-1),
819 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
820 _cur_card_in_prt(HeapRegion::CardsPerRegion),
821 _fine_cur_prt(NULL),
822 _n_yielded_coarse(0),
823 _n_yielded_fine(0),
824 _n_yielded_sparse(0),
825 _sparse_iter(&hrrs->_other_regions._sparse_table) {}
826
827 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
828 if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
829 // Go to the next card.
830 _coarse_cur_region_cur_card++;
831 // Was the last the last card in the current region?
832 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
833 // Yes: find the next region. This may leave _coarse_cur_region_index
834 // Set to the last index, in which case there are no more coarse
835 // regions.
836 _coarse_cur_region_index =
837 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
838 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
839 _coarse_cur_region_cur_card = 0;
840 HeapWord* r_bot =
841 _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
842 _cur_region_card_offset = _bot->index_for(r_bot);
843 } else {
844 return false;
845 }
846 }
847 // If we didn't return false above, then we can yield a card.
848 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
849 return true;
850 }
851
852 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
853 if (fine_has_next()) {
854 _cur_card_in_prt =
855 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
856 }
857 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) {
858 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for
859 // the remembered set.
860 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) {
861 return false;
862 }
863 PerRegionTable* next_prt = _fine_cur_prt->next();
864 switch_to_prt(next_prt);
865 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
866 }
867
868 card_index = _cur_region_card_offset + _cur_card_in_prt;
869 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion,
870 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt);
871 return true;
872 }
873
874 bool HeapRegionRemSetIterator::fine_has_next() {
875 return _cur_card_in_prt != HeapRegion::CardsPerRegion;
876 }
877
878 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) {
879 assert(prt != NULL, "Cannot switch to NULL prt");
880 _fine_cur_prt = prt;
881
882 HeapWord* r_bot = _fine_cur_prt->hr()->bottom();
883 _cur_region_card_offset = _bot->index_for(r_bot);
884
885 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1.
886 // To avoid special-casing this start case, and not miss the first bitmap
887 // entry, initialize _cur_region_cur_card with -1 instead of 0.
888 _cur_card_in_prt = (size_t)-1;
889 }
890
891 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
892 switch (_is) {
893 case Sparse: {
894 if (_sparse_iter.has_next(card_index)) {
895 _n_yielded_sparse++;
896 return true;
897 }
898 // Otherwise, deliberate fall-through
899 _is = Fine;
900 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts;
901 if (initial_fine_prt != NULL) {
902 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts);
903 }
904 }
905 case Fine:
906 if (fine_has_next(card_index)) {
907 _n_yielded_fine++;
908 return true;
909 }
910 // Otherwise, deliberate fall-through
911 _is = Coarse;
912 case Coarse:
913 if (coarse_has_next(card_index)) {
914 _n_yielded_coarse++;
915 return true;
916 }
917 // Otherwise...
918 break;
919 }
920 assert(ParallelGCThreads > 1 ||
921 n_yielded() == _hrrs->occupied(),
922 "Should have yielded all the cards in the rem set "
923 "(in the non-par case).");
924 return false;
925 }
926
927 void HeapRegionRemSet::reset_for_cleanup_tasks() {
928 SparsePRT::reset_for_cleanup_tasks();
929 }
930
931 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
932 _other_regions.do_cleanup_work(hrrs_cleanup_task);
933 }
934
935 void
936 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
937 SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
938 }
939
940 #ifndef PRODUCT
941 void HeapRegionRemSet::test() {
942 os::sleep(Thread::current(), (jlong)5000, false);
943 G1CollectedHeap* g1h = G1CollectedHeap::heap();
944
945 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
946 // hash bucket.
947 HeapRegion* hr0 = g1h->region_at(0);
948 HeapRegion* hr1 = g1h->region_at(1);
949 HeapRegion* hr2 = g1h->region_at(5);
950 HeapRegion* hr3 = g1h->region_at(6);
951 HeapRegion* hr4 = g1h->region_at(7);
952 HeapRegion* hr5 = g1h->region_at(8);
953
954 HeapWord* hr1_start = hr1->bottom();
955 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
956 HeapWord* hr1_last = hr1->end() - 1;
957
958 HeapWord* hr2_start = hr2->bottom();
959 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
960 HeapWord* hr2_last = hr2->end() - 1;
961
962 HeapWord* hr3_start = hr3->bottom();
963 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
964 HeapWord* hr3_last = hr3->end() - 1;
965
966 HeapRegionRemSet* hrrs = hr0->rem_set();
967
968 // Make three references from region 0x101...
969 hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
970 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
971 hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
972
973 hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
974 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
975 hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
976
977 hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
978 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
979 hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
980
981 // Now cause a coarsening.
982 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
983 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
984
985 // Now, does iteration yield these three?
986 HeapRegionRemSetIterator iter(hrrs);
987 size_t sum = 0;
988 size_t card_index;
989 while (iter.has_next(card_index)) {
990 HeapWord* card_start =
991 G1CollectedHeap::heap()->bot()->address_for_index(card_index);
992 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start));
993 sum++;
994 }
995 guarantee(sum == 11 - 3 + 2048, "Failure");
996 guarantee(sum == hrrs->occupied(), "Failure");
997 }
998 #endif