1 /*
2 * Copyright (c) 2001, 2019, 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/g1Arguments.hpp"
27 #include "gc/g1/g1CollectedHeap.inline.hpp"
28 #include "gc/g1/g1ConcurrentRefine.hpp"
29 #include "gc/g1/heapRegion.hpp"
30 #include "gc/g1/heapRegionManager.inline.hpp"
31 #include "gc/g1/heapRegionSet.inline.hpp"
32 #include "gc/g1/heterogeneousHeapRegionManager.hpp"
33 #include "logging/logStream.hpp"
34 #include "memory/allocation.hpp"
35 #include "utilities/bitMap.inline.hpp"
36
37 class MasterFreeRegionListChecker : public HeapRegionSetChecker {
38 public:
39 void check_mt_safety() {
40 // Master Free List MT safety protocol:
41 // (a) If we're at a safepoint, operations on the master free list
42 // should be invoked by either the VM thread (which will serialize
43 // them) or by the GC workers while holding the
44 // FreeList_lock.
45 // (b) If we're not at a safepoint, operations on the master free
46 // list should be invoked while holding the Heap_lock.
47
48 if (SafepointSynchronize::is_at_safepoint()) {
49 guarantee(Thread::current()->is_VM_thread() ||
50 FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint");
51 } else {
52 guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint");
53 }
54 }
55 bool is_correct_type(HeapRegion* hr) { return hr->is_free(); }
56 const char* get_description() { return "Free Regions"; }
57 };
58
59 HeapRegionManager::HeapRegionManager() :
60 _bot_mapper(NULL),
61 _cardtable_mapper(NULL),
62 _card_counts_mapper(NULL),
63 _available_map(mtGC),
64 _num_committed(0),
65 _allocated_heapregions_length(0),
66 _regions(), _heap_mapper(NULL),
67 _prev_bitmap_mapper(NULL),
68 _next_bitmap_mapper(NULL),
69 _free_list("Free list", new MasterFreeRegionListChecker())
70 { }
71
72 HeapRegionManager* HeapRegionManager::create_manager(G1CollectedHeap* heap) {
73 if (G1Arguments::is_heterogeneous_heap()) {
74 return new HeterogeneousHeapRegionManager((uint)(G1Arguments::heap_max_size_bytes() / HeapRegion::GrainBytes) /*heap size as num of regions*/);
75 }
76 return new HeapRegionManager();
77 }
78
79 void HeapRegionManager::initialize(G1RegionToSpaceMapper* heap_storage,
80 G1RegionToSpaceMapper* prev_bitmap,
81 G1RegionToSpaceMapper* next_bitmap,
82 G1RegionToSpaceMapper* bot,
83 G1RegionToSpaceMapper* cardtable,
84 G1RegionToSpaceMapper* card_counts) {
85 _allocated_heapregions_length = 0;
86
87 _heap_mapper = heap_storage;
88
89 _prev_bitmap_mapper = prev_bitmap;
90 _next_bitmap_mapper = next_bitmap;
91
92 _bot_mapper = bot;
93 _cardtable_mapper = cardtable;
94
95 _card_counts_mapper = card_counts;
96
97 MemRegion reserved = heap_storage->reserved();
98 _regions.initialize(reserved.start(), reserved.end(), HeapRegion::GrainBytes);
99
100 _available_map.initialize(_regions.length());
101 }
102
103 bool HeapRegionManager::is_available(uint region) const {
104 return _available_map.at(region);
105 }
106
107 // If log is enabled, compare actual node index and the node index. If those are different
108 // return the actual node index.
109 // If log is disabled, just return the node index.
110 static uint verify_actual_node_index(HeapWord* addr, uint node_index) {
111 LogTarget(Debug, gc, heap, numa, verification) lt;
112
113 if (lt.is_enabled()) {
114 LogStream ls(lt);
115
116 uint actual_node_index = G1MemoryNodeManager::mgr()->index_of_address(addr);
117 if (node_index != actual_node_index) {
118 ls.print_cr("Heap Region (%u) has different node index. actual index=%u, index=%u",
119 G1CollectedHeap::heap()->addr_to_region(addr), actual_node_index, node_index);
120 }
121 return actual_node_index;
122 }
123 return node_index;
124 }
125
126 HeapRegion* HeapRegionManager::allocate_free_region(HeapRegionType type, uint requested_node_index) {
127 G1MemoryNodeManager* mgr = G1MemoryNodeManager::mgr();
128 HeapRegion* hr = NULL;
129 bool from_head = !type.is_young();
130
131 if (mgr->num_active_nodes() > 1 && mgr->is_valid_node_index(requested_node_index)) {
132 // Try to allocate with requested node index.
133 hr = _free_list.remove_region_with_node_index(from_head, requested_node_index, NULL);
134 }
135
136 if (hr == NULL) {
137 // If there's a single active node or we did not get a region from our requested node,
138 // try without requested node index.
139 hr = _free_list.remove_region(from_head);
140 }
141
142 if (hr != NULL) {
143 assert(hr->next() == NULL, "Single region should not have next");
144 assert(is_available(hr->hrm_index()), "Must be committed");
145
146 verify_actual_node_index(hr->bottom(), hr->node_index());
147 }
148
149 return hr;
150 }
151
152 #ifdef ASSERT
153 bool HeapRegionManager::is_free(HeapRegion* hr) const {
154 return _free_list.contains(hr);
155 }
156 #endif
157
158 HeapRegion* HeapRegionManager::new_heap_region(uint hrm_index) {
159 G1CollectedHeap* g1h = G1CollectedHeap::heap();
160 HeapWord* bottom = g1h->bottom_addr_for_region(hrm_index);
161 MemRegion mr(bottom, bottom + HeapRegion::GrainWords);
162 assert(reserved().contains(mr), "invariant");
163 return g1h->new_heap_region(hrm_index, mr);
164 }
165
166 void HeapRegionManager::commit_regions(uint index, size_t num_regions, WorkGang* pretouch_gang) {
167 guarantee(num_regions > 0, "Must commit more than zero regions");
168 guarantee(_num_committed + num_regions <= max_length(), "Cannot commit more than the maximum amount of regions");
169
170 _num_committed += (uint)num_regions;
171
172 _heap_mapper->commit_regions(index, num_regions, pretouch_gang);
173
174 // Also commit auxiliary data
175 _prev_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang);
176 _next_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang);
177
178 _bot_mapper->commit_regions(index, num_regions, pretouch_gang);
179 _cardtable_mapper->commit_regions(index, num_regions, pretouch_gang);
180
181 _card_counts_mapper->commit_regions(index, num_regions, pretouch_gang);
182 }
183
184 void HeapRegionManager::uncommit_regions(uint start, size_t num_regions) {
185 guarantee(num_regions >= 1, "Need to specify at least one region to uncommit, tried to uncommit zero regions at %u", start);
186 guarantee(_num_committed >= num_regions, "pre-condition");
187
188 // Reset node index to distinguish with committed regions.
189 for (uint i = start; i < start + num_regions; i++) {
190 at(i)->set_node_index(G1MemoryNodeManager::InvalidNodeIndex);
191 }
192
193 // Print before uncommitting.
194 if (G1CollectedHeap::heap()->hr_printer()->is_active()) {
195 for (uint i = start; i < start + num_regions; i++) {
196 HeapRegion* hr = at(i);
197 G1CollectedHeap::heap()->hr_printer()->uncommit(hr);
198 }
199 }
200
201 _num_committed -= (uint)num_regions;
202
203 _available_map.par_clear_range(start, start + num_regions, BitMap::unknown_range);
204 _heap_mapper->uncommit_regions(start, num_regions);
205
206 // Also uncommit auxiliary data
207 _prev_bitmap_mapper->uncommit_regions(start, num_regions);
208 _next_bitmap_mapper->uncommit_regions(start, num_regions);
209
210 _bot_mapper->uncommit_regions(start, num_regions);
211 _cardtable_mapper->uncommit_regions(start, num_regions);
212
213 _card_counts_mapper->uncommit_regions(start, num_regions);
214 }
215
216 static void print_node_id_of_regions(uint start, uint num_regions) {
217 LogTarget(Trace, gc, heap, numa) lt;
218
219 if (lt.is_enabled()) {
220 LogStream ls(lt);
221
222 // Below logs are checked by TestG1NUMATouchRegions.java.
223 ls.print_cr("Numa id of heap regions from %u to %u", start, start + num_regions - 1);
224 ls.print_cr("Heap Region# : numa id of pages");
225
226 for (uint i = start; i < start + num_regions; i++) {
227 ls.print_cr("%6u : %02u", i, G1CollectedHeap::heap()->region_at(i)->node_index());
228 }
229 }
230 }
231
232 // Set node index of the given HeapRegion.
233 // If AlwaysPreTouch is enabled, set with actual node index.
234 // If it is disabled, set with preferred node index which is already decided.
235 static void set_heapregion_node_index(HeapRegion* hr) {
236 uint node_index = G1MemoryNodeManager::mgr()->preferred_index_for_address(hr->bottom());
237 if(AlwaysPreTouch) {
238 // If we already pretouched, we can check actual node index here.
239 node_index = verify_actual_node_index(hr->bottom(), node_index);
240 }
241 hr->set_node_index(node_index);
242 }
243
244 void HeapRegionManager::make_regions_available(uint start, uint num_regions, WorkGang* pretouch_gang) {
245 guarantee(num_regions > 0, "No point in calling this for zero regions");
246 commit_regions(start, num_regions, pretouch_gang);
247 for (uint i = start; i < start + num_regions; i++) {
248 if (_regions.get_by_index(i) == NULL) {
249 HeapRegion* new_hr = new_heap_region(i);
250 OrderAccess::storestore();
251 _regions.set_by_index(i, new_hr);
252 _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1);
253 }
254 }
255
256 _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range);
257
258 for (uint i = start; i < start + num_regions; i++) {
259 assert(is_available(i), "Just made region %u available but is apparently not.", i);
260 HeapRegion* hr = at(i);
261 if (G1CollectedHeap::heap()->hr_printer()->is_active()) {
262 G1CollectedHeap::heap()->hr_printer()->commit(hr);
263 }
264 HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i);
265 MemRegion mr(bottom, bottom + HeapRegion::GrainWords);
266
267 hr->initialize(mr);
268 // Set node index of the heap region after initialization but before inserting
269 // to free list.
270 set_heapregion_node_index(hr);
271 insert_into_free_list(at(i));
272 }
273
274 print_node_id_of_regions(start, num_regions);
275 }
276
277 MemoryUsage HeapRegionManager::get_auxiliary_data_memory_usage() const {
278 size_t used_sz =
279 _prev_bitmap_mapper->committed_size() +
280 _next_bitmap_mapper->committed_size() +
281 _bot_mapper->committed_size() +
282 _cardtable_mapper->committed_size() +
283 _card_counts_mapper->committed_size();
284
285 size_t committed_sz =
286 _prev_bitmap_mapper->reserved_size() +
287 _next_bitmap_mapper->reserved_size() +
288 _bot_mapper->reserved_size() +
289 _cardtable_mapper->reserved_size() +
290 _card_counts_mapper->reserved_size();
291
292 return MemoryUsage(0, used_sz, committed_sz, committed_sz);
293 }
294
295 uint HeapRegionManager::expand_by(uint num_regions, WorkGang* pretouch_workers) {
296 return expand_at(0, num_regions, pretouch_workers);
297 }
298
299 uint HeapRegionManager::expand_at(uint start, uint num_regions, WorkGang* pretouch_workers) {
300 if (num_regions == 0) {
301 return 0;
302 }
303
304 uint cur = start;
305 uint idx_last_found = 0;
306 uint num_last_found = 0;
307
308 uint expanded = 0;
309
310 while (expanded < num_regions &&
311 (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) {
312 uint to_expand = MIN2(num_regions - expanded, num_last_found);
313 make_regions_available(idx_last_found, to_expand, pretouch_workers);
314 expanded += to_expand;
315 cur = idx_last_found + num_last_found + 1;
316 }
317
318 verify_optional();
319 return expanded;
320 }
321
322 uint HeapRegionManager::expand_on_preferred_node(uint preferred_index) {
323 uint expand_candidate = UINT_MAX;
324 for (uint i = 0; i < max_length(); i++) {
325 if (is_available(i)) {
326 // Already in use continue
327 continue;
328 }
329 // Always save the candidate so we can expand later on.
330 expand_candidate = i;
331 if (is_on_preferred_index(expand_candidate, preferred_index)) {
332 // We have found a candidate on the preffered node, break.
333 break;
334 }
335 }
336
337 if (expand_candidate == UINT_MAX) {
338 // No regions left, expand failed.
339 return 0;
340 }
341
342 make_regions_available(expand_candidate, 1, NULL);
343 return 1;
344 }
345
346 bool HeapRegionManager::is_on_preferred_index(uint region_index, uint preferred_node_index) {
347 uint region_node_index = G1MemoryNodeManager::mgr()->preferred_index_for_address(
348 G1CollectedHeap::heap()->bottom_addr_for_region(region_index));
349 return region_node_index == preferred_node_index ||
350 preferred_node_index == G1MemoryNodeManager::AnyNodeIndex;
351 }
352
353 uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) {
354 uint found = 0;
355 size_t length_found = 0;
356 uint cur = 0;
357
358 while (length_found < num && cur < max_length()) {
359 HeapRegion* hr = _regions.get_by_index(cur);
360 if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) {
361 // This region is a potential candidate for allocation into.
362 length_found++;
363 } else {
364 // This region is not a candidate. The next region is the next possible one.
365 found = cur + 1;
366 length_found = 0;
367 }
368 cur++;
369 }
370
371 if (length_found == num) {
372 for (uint i = found; i < (found + num); i++) {
373 HeapRegion* hr = _regions.get_by_index(i);
374 // sanity check
375 guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()),
376 "Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT
377 " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr));
378 }
379 return found;
380 } else {
381 return G1_NO_HRM_INDEX;
382 }
383 }
384
385 HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const {
386 guarantee(r != NULL, "Start region must be a valid region");
387 guarantee(is_available(r->hrm_index()), "Trying to iterate starting from region %u which is not in the heap", r->hrm_index());
388 for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) {
389 HeapRegion* hr = _regions.get_by_index(i);
390 if (is_available(i)) {
391 return hr;
392 }
393 }
394 return NULL;
395 }
396
397 void HeapRegionManager::iterate(HeapRegionClosure* blk) const {
398 uint len = max_length();
399
400 for (uint i = 0; i < len; i++) {
401 if (!is_available(i)) {
402 continue;
403 }
404 guarantee(at(i) != NULL, "Tried to access region %u that has a NULL HeapRegion*", i);
405 bool res = blk->do_heap_region(at(i));
406 if (res) {
407 blk->set_incomplete();
408 return;
409 }
410 }
411 }
412
413 uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx) const {
414 guarantee(res_idx != NULL, "checking");
415 guarantee(start_idx <= (max_length() + 1), "checking");
416
417 uint num_regions = 0;
418
419 uint cur = start_idx;
420 while (cur < max_length() && is_available(cur)) {
421 cur++;
422 }
423 if (cur == max_length()) {
424 return num_regions;
425 }
426 *res_idx = cur;
427 while (cur < max_length() && !is_available(cur)) {
428 cur++;
429 }
430 num_regions = cur - *res_idx;
431 #ifdef ASSERT
432 for (uint i = *res_idx; i < (*res_idx + num_regions); i++) {
433 assert(!is_available(i), "just checking");
434 }
435 assert(cur == max_length() || num_regions == 0 || is_available(cur),
436 "The region at the current position %u must be available or at the end of the heap.", cur);
437 #endif
438 return num_regions;
439 }
440
441 uint HeapRegionManager::find_highest_free(bool* expanded) {
442 // Loop downwards from the highest region index, looking for an
443 // entry which is either free or not yet committed. If not yet
444 // committed, expand_at that index.
445 uint curr = max_length() - 1;
446 while (true) {
447 HeapRegion *hr = _regions.get_by_index(curr);
448 if (hr == NULL || !is_available(curr)) {
449 uint res = expand_at(curr, 1, NULL);
450 if (res == 1) {
451 *expanded = true;
452 return curr;
453 }
454 } else {
455 if (hr->is_free()) {
456 *expanded = false;
457 return curr;
458 }
459 }
460 if (curr == 0) {
461 return G1_NO_HRM_INDEX;
462 }
463 curr--;
464 }
465 }
466
467 bool HeapRegionManager::allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers) {
468 size_t commits = 0;
469 uint start_index = (uint)_regions.get_index_by_address(range.start());
470 uint last_index = (uint)_regions.get_index_by_address(range.last());
471
472 // Ensure that each G1 region in the range is free, returning false if not.
473 // Commit those that are not yet available, and keep count.
474 for (uint curr_index = start_index; curr_index <= last_index; curr_index++) {
475 if (!is_available(curr_index)) {
476 commits++;
477 expand_at(curr_index, 1, pretouch_workers);
478 }
479 HeapRegion* curr_region = _regions.get_by_index(curr_index);
480 if (!curr_region->is_free()) {
481 return false;
482 }
483 }
484
485 allocate_free_regions_starting_at(start_index, (last_index - start_index) + 1);
486 *commit_count = commits;
487 return true;
488 }
489
490 void HeapRegionManager::par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) const {
491 // Every worker will actually look at all regions, skipping over regions that
492 // are currently not committed.
493 // This also (potentially) iterates over regions newly allocated during GC. This
494 // is no problem except for some extra work.
495 const uint n_regions = hrclaimer->n_regions();
496 for (uint count = 0; count < n_regions; count++) {
497 const uint index = (start_index + count) % n_regions;
498 assert(index < n_regions, "sanity");
499 // Skip over unavailable regions
500 if (!is_available(index)) {
501 continue;
502 }
503 HeapRegion* r = _regions.get_by_index(index);
504 // We'll ignore regions already claimed.
505 // However, if the iteration is specified as concurrent, the values for
506 // is_starts_humongous and is_continues_humongous can not be trusted,
507 // and we should just blindly iterate over regions regardless of their
508 // humongous status.
509 if (hrclaimer->is_region_claimed(index)) {
510 continue;
511 }
512 // OK, try to claim it
513 if (!hrclaimer->claim_region(index)) {
514 continue;
515 }
516 bool res = blk->do_heap_region(r);
517 if (res) {
518 return;
519 }
520 }
521 }
522
523 uint HeapRegionManager::shrink_by(uint num_regions_to_remove) {
524 assert(length() > 0, "the region sequence should not be empty");
525 assert(length() <= _allocated_heapregions_length, "invariant");
526 assert(_allocated_heapregions_length > 0, "we should have at least one region committed");
527 assert(num_regions_to_remove < length(), "We should never remove all regions");
528
529 if (num_regions_to_remove == 0) {
530 return 0;
531 }
532
533 uint removed = 0;
534 uint cur = _allocated_heapregions_length - 1;
535 uint idx_last_found = 0;
536 uint num_last_found = 0;
537
538 while ((removed < num_regions_to_remove) &&
539 (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) {
540 uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found);
541
542 shrink_at(idx_last_found + num_last_found - to_remove, to_remove);
543
544 cur = idx_last_found;
545 removed += to_remove;
546 }
547
548 verify_optional();
549
550 return removed;
551 }
552
553 void HeapRegionManager::shrink_at(uint index, size_t num_regions) {
554 #ifdef ASSERT
555 for (uint i = index; i < (index + num_regions); i++) {
556 assert(is_available(i), "Expected available region at index %u", i);
557 assert(at(i)->is_empty(), "Expected empty region at index %u", i);
558 assert(at(i)->is_free(), "Expected free region at index %u", i);
559 }
560 #endif
561 uncommit_regions(index, num_regions);
562 }
563
564 uint HeapRegionManager::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const {
565 guarantee(start_idx < _allocated_heapregions_length, "checking");
566 guarantee(res_idx != NULL, "checking");
567
568 uint num_regions_found = 0;
569
570 jlong cur = start_idx;
571 while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) {
572 cur--;
573 }
574 if (cur == -1) {
575 return num_regions_found;
576 }
577 jlong old_cur = cur;
578 // cur indexes the first empty region
579 while (cur != -1 && is_available(cur) && at(cur)->is_empty()) {
580 cur--;
581 }
582 *res_idx = cur + 1;
583 num_regions_found = old_cur - cur;
584
585 #ifdef ASSERT
586 for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) {
587 assert(at(i)->is_empty(), "just checking");
588 }
589 #endif
590 return num_regions_found;
591 }
592
593 void HeapRegionManager::verify() {
594 guarantee(length() <= _allocated_heapregions_length,
595 "invariant: _length: %u _allocated_length: %u",
596 length(), _allocated_heapregions_length);
597 guarantee(_allocated_heapregions_length <= max_length(),
598 "invariant: _allocated_length: %u _max_length: %u",
599 _allocated_heapregions_length, max_length());
600
601 bool prev_committed = true;
602 uint num_committed = 0;
603 HeapWord* prev_end = heap_bottom();
604 for (uint i = 0; i < _allocated_heapregions_length; i++) {
605 if (!is_available(i)) {
606 prev_committed = false;
607 continue;
608 }
609 num_committed++;
610 HeapRegion* hr = _regions.get_by_index(i);
611 guarantee(hr != NULL, "invariant: i: %u", i);
612 guarantee(!prev_committed || hr->bottom() == prev_end,
613 "invariant i: %u " HR_FORMAT " prev_end: " PTR_FORMAT,
614 i, HR_FORMAT_PARAMS(hr), p2i(prev_end));
615 guarantee(hr->hrm_index() == i,
616 "invariant: i: %u hrm_index(): %u", i, hr->hrm_index());
617 // Asserts will fire if i is >= _length
618 HeapWord* addr = hr->bottom();
619 guarantee(addr_to_region(addr) == hr, "sanity");
620 // We cannot check whether the region is part of a particular set: at the time
621 // this method may be called, we have only completed allocation of the regions,
622 // but not put into a region set.
623 prev_committed = true;
624 prev_end = hr->end();
625 }
626 for (uint i = _allocated_heapregions_length; i < max_length(); i++) {
627 guarantee(_regions.get_by_index(i) == NULL, "invariant i: %u", i);
628 }
629
630 guarantee(num_committed == _num_committed, "Found %u committed regions, but should be %u", num_committed, _num_committed);
631 _free_list.verify();
632 }
633
634 #ifndef PRODUCT
635 void HeapRegionManager::verify_optional() {
636 verify();
637 }
638 #endif // PRODUCT
639
640 HeapRegionClaimer::HeapRegionClaimer(uint n_workers) :
641 _n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm->_allocated_heapregions_length), _claims(NULL) {
642 assert(n_workers > 0, "Need at least one worker.");
643 uint* new_claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC);
644 memset(new_claims, Unclaimed, sizeof(*_claims) * _n_regions);
645 _claims = new_claims;
646 }
647
648 HeapRegionClaimer::~HeapRegionClaimer() {
649 FREE_C_HEAP_ARRAY(uint, _claims);
650 }
651
652 uint HeapRegionClaimer::offset_for_worker(uint worker_id) const {
653 assert(worker_id < _n_workers, "Invalid worker_id.");
654 return _n_regions * worker_id / _n_workers;
655 }
656
657 bool HeapRegionClaimer::is_region_claimed(uint region_index) const {
658 assert(region_index < _n_regions, "Invalid index.");
659 return _claims[region_index] == Claimed;
660 }
661
662 bool HeapRegionClaimer::claim_region(uint region_index) {
663 assert(region_index < _n_regions, "Invalid index.");
664 uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed);
665 return old_val == Unclaimed;
666 }