1 /*
2 * Copyright (c) 2002, 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 "classfile/classLoaderData.hpp"
27 #include "gc_interface/collectedHeap.hpp"
28 #include "memory/genCollectedHeap.hpp"
29 #include "memory/heapInspection.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "runtime/os.hpp"
32 #include "utilities/globalDefinitions.hpp"
33 #include "utilities/macros.hpp"
34 #if INCLUDE_ALL_GCS
35 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
36 #endif // INCLUDE_ALL_GCS
37
38 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
39
40 // HeapInspection
41
42 int KlassInfoEntry::compare(KlassInfoEntry* e1, KlassInfoEntry* e2) {
43 if(e1->_instance_words > e2->_instance_words) {
44 return -1;
45 } else if(e1->_instance_words < e2->_instance_words) {
46 return 1;
47 }
48 // Sort alphabetically, note 'Z' < '[' < 'a', but it's better to group
49 // the array classes before all the instance classes.
50 ResourceMark rm;
51 const char* name1 = e1->klass()->external_name();
52 const char* name2 = e2->klass()->external_name();
53 bool d1 = (name1[0] == '[');
54 bool d2 = (name2[0] == '[');
55 if (d1 && !d2) {
56 return -1;
57 } else if (d2 && !d1) {
58 return 1;
59 } else {
60 return strcmp(name1, name2);
61 }
62 }
63
64 const char* KlassInfoEntry::name() const {
65 const char* name;
66 if (_klass->name() != NULL) {
67 name = _klass->external_name();
68 } else {
69 if (_klass == Universe::boolArrayKlassObj()) name = "<boolArrayKlass>"; else
70 if (_klass == Universe::charArrayKlassObj()) name = "<charArrayKlass>"; else
71 if (_klass == Universe::singleArrayKlassObj()) name = "<singleArrayKlass>"; else
72 if (_klass == Universe::doubleArrayKlassObj()) name = "<doubleArrayKlass>"; else
73 if (_klass == Universe::byteArrayKlassObj()) name = "<byteArrayKlass>"; else
74 if (_klass == Universe::shortArrayKlassObj()) name = "<shortArrayKlass>"; else
75 if (_klass == Universe::intArrayKlassObj()) name = "<intArrayKlass>"; else
76 if (_klass == Universe::longArrayKlassObj()) name = "<longArrayKlass>"; else
77 name = "<no name>";
78 }
79 return name;
80 }
81
82 void KlassInfoEntry::print_on(outputStream* st) const {
83 ResourceMark rm;
84
85 // simplify the formatting (ILP32 vs LP64) - always cast the numbers to 64-bit
86 st->print_cr(INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13) " %s",
87 (jlong) _instance_count,
88 (julong) _instance_words * HeapWordSize,
89 name());
90 }
91
92 KlassInfoEntry* KlassInfoBucket::lookup(Klass* const k) {
93 KlassInfoEntry* elt = _list;
94 while (elt != NULL) {
95 if (elt->is_equal(k)) {
96 return elt;
97 }
98 elt = elt->next();
99 }
100 elt = new (std::nothrow) KlassInfoEntry(k, list());
101 // We may be out of space to allocate the new entry.
102 if (elt != NULL) {
103 set_list(elt);
104 }
105 return elt;
106 }
107
108 void KlassInfoBucket::iterate(KlassInfoClosure* cic) {
109 KlassInfoEntry* elt = _list;
110 while (elt != NULL) {
111 cic->do_cinfo(elt);
112 elt = elt->next();
113 }
114 }
115
116 void KlassInfoBucket::empty() {
117 KlassInfoEntry* elt = _list;
118 _list = NULL;
119 while (elt != NULL) {
120 KlassInfoEntry* next = elt->next();
121 delete elt;
122 elt = next;
123 }
124 }
125
126 void KlassInfoTable::AllClassesFinder::do_klass(Klass* k) {
127 // This has the SIDE EFFECT of creating a KlassInfoEntry
128 // for <k>, if one doesn't exist yet.
129 _table->lookup(k);
130 }
131
132 KlassInfoTable::KlassInfoTable(bool add_all_classes) {
133 _size_of_instances_in_words = 0;
134 _size = 0;
135 _ref = (HeapWord*) Universe::boolArrayKlassObj();
136 _buckets =
137 (KlassInfoBucket*) AllocateHeap(sizeof(KlassInfoBucket) * _num_buckets,
138 mtInternal, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
139 if (_buckets != NULL) {
140 _size = _num_buckets;
141 for (int index = 0; index < _size; index++) {
142 _buckets[index].initialize();
143 }
144 if (add_all_classes) {
145 AllClassesFinder finder(this);
146 ClassLoaderDataGraph::classes_do(&finder);
147 }
148 }
149 }
150
151 KlassInfoTable::~KlassInfoTable() {
152 if (_buckets != NULL) {
153 for (int index = 0; index < _size; index++) {
154 _buckets[index].empty();
155 }
156 FREE_C_HEAP_ARRAY(KlassInfoBucket, _buckets);
157 _size = 0;
158 }
159 }
160
161 uint KlassInfoTable::hash(const Klass* p) {
162 return (uint)(((uintptr_t)p - (uintptr_t)_ref) >> 2);
163 }
164
165 KlassInfoEntry* KlassInfoTable::lookup(Klass* k) {
166 uint idx = hash(k) % _size;
167 assert(_buckets != NULL, "Allocation failure should have been caught");
168 KlassInfoEntry* e = _buckets[idx].lookup(k);
169 // Lookup may fail if this is a new klass for which we
170 // could not allocate space for an new entry.
171 assert(e == NULL || k == e->klass(), "must be equal");
172 return e;
173 }
174
175 // Return false if the entry could not be recorded on account
176 // of running out of space required to create a new entry.
177 bool KlassInfoTable::record_instance(const oop obj) {
178 Klass* k = obj->klass();
179 KlassInfoEntry* elt = lookup(k);
180 // elt may be NULL if it's a new klass for which we
181 // could not allocate space for a new entry in the hashtable.
182 if (elt != NULL) {
183 elt->set_count(elt->count() + 1);
184 elt->set_words(elt->words() + obj->size());
185 _size_of_instances_in_words += obj->size();
186 return true;
187 } else {
188 return false;
189 }
190 }
191
192 void KlassInfoTable::iterate(KlassInfoClosure* cic) {
193 assert(_size == 0 || _buckets != NULL, "Allocation failure should have been caught");
194 for (int index = 0; index < _size; index++) {
195 _buckets[index].iterate(cic);
196 }
197 }
198
199 size_t KlassInfoTable::size_of_instances_in_words() const {
200 return _size_of_instances_in_words;
201 }
202
203 int KlassInfoHisto::sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2) {
204 return (*e1)->compare(*e1,*e2);
205 }
206
207 KlassInfoHisto::KlassInfoHisto(KlassInfoTable* cit, const char* title) :
208 _cit(cit),
209 _title(title) {
210 _elements = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<KlassInfoEntry*>(_histo_initial_size, true);
211 }
212
213 KlassInfoHisto::~KlassInfoHisto() {
214 delete _elements;
215 }
216
217 void KlassInfoHisto::add(KlassInfoEntry* cie) {
218 elements()->append(cie);
219 }
220
221 void KlassInfoHisto::sort() {
222 elements()->sort(KlassInfoHisto::sort_helper);
223 }
224
225 void KlassInfoHisto::print_elements(outputStream* st) const {
226 // simplify the formatting (ILP32 vs LP64) - store the sum in 64-bit
227 jlong total = 0;
228 julong totalw = 0;
229 for(int i=0; i < elements()->length(); i++) {
230 st->print("%4d: ", i+1);
231 elements()->at(i)->print_on(st);
232 total += elements()->at(i)->count();
233 totalw += elements()->at(i)->words();
234 }
235 st->print_cr("Total " INT64_FORMAT_W(13) " " UINT64_FORMAT_W(13),
236 total, totalw * HeapWordSize);
237 }
238
239 #define MAKE_COL_NAME(field, name, help) #name,
240 #define MAKE_COL_HELP(field, name, help) help,
241
242 static const char *name_table[] = {
243 HEAP_INSPECTION_COLUMNS_DO(MAKE_COL_NAME)
244 };
245
246 static const char *help_table[] = {
247 HEAP_INSPECTION_COLUMNS_DO(MAKE_COL_HELP)
248 };
249
250 bool KlassInfoHisto::is_selected(const char *col_name) {
251 if (_selected_columns == NULL) {
252 return true;
253 }
254 if (strcmp(_selected_columns, col_name) == 0) {
255 return true;
256 }
257
258 const char *start = strstr(_selected_columns, col_name);
259 if (start == NULL) {
260 return false;
261 }
262
263 // The following must be true, because _selected_columns != col_name
264 if (start > _selected_columns && start[-1] != ',') {
265 return false;
266 }
267 char x = start[strlen(col_name)];
268 if (x != ',' && x != '\0') {
269 return false;
270 }
271
272 return true;
273 }
274
275 PRAGMA_FORMAT_NONLITERAL_IGNORED_EXTERNAL
276 void KlassInfoHisto::print_title(outputStream* st, bool csv_format,
277 bool selected[], int width_table[],
278 const char *name_table[]) {
279 if (csv_format) {
280 st->print("Index,Super");
281 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
282 if (selected[c]) {st->print(",%s", name_table[c]);}
283 }
284 st->print(",ClassName");
285 } else {
286 st->print("Index Super");
287 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
288 PRAGMA_DIAG_PUSH
289 PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
290 if (selected[c]) {st->print(str_fmt(width_table[c]), name_table[c]);}
291 PRAGMA_DIAG_POP
292 }
293 st->print(" ClassName");
294 }
295
296 if (is_selected("ClassLoader")) {
297 st->print(",ClassLoader");
298 }
299 st->cr();
300 }
301
302 class HierarchyClosure : public KlassInfoClosure {
303 private:
304 GrowableArray<KlassInfoEntry*> *_elements;
305 public:
306 HierarchyClosure(GrowableArray<KlassInfoEntry*> *_elements) : _elements(_elements) {}
307
308 void do_cinfo(KlassInfoEntry* cie) {
309 // ignore array classes
310 if (cie->klass()->oop_is_instance()) {
311 _elements->append(cie);
312 }
313 }
314 };
315
316 void KlassHierarchy::print_class_hierarchy(outputStream* st) {
317 ResourceMark rm;
318 int i;
319 Stack <KlassInfoEntry*, mtClass> class_stack;
320 Stack <KlassInfoEntry*, mtClass> super_stack;
321 GrowableArray<KlassInfoEntry*> elements;
322
323 // Add all classes to the KlassInfoTable, which allows for quick lookup.
324 // A KlassInfoEntry will be created for each class.
325 KlassInfoTable cit(true);
326 if (cit.allocation_failed()) {
327 st->print_cr("WARNING: Ran out of C-heap; hierarchy not generated");
328 return;
329 }
330
331 // Add all created KlassInfoEntry instances to the elements array for easy
332 // iteration, and to allow each KlassInfoEntry instance to have a unique index.
333 HierarchyClosure hc(&elements);
334 cit.iterate(&hc);
335
336 // Set the index for each class
337 for(i=0; i < elements.length(); i++) {
338 elements.at(i)->set_index(i+1);
339 }
340
341 // Iterate over all the classes, adding each class to the subclass array of
342 // its superclass.
343 for(i=0; i < elements.length(); i++) {
344 KlassInfoEntry* e = (KlassInfoEntry*)elements.at(i);
345 const Klass* k = e->klass();
346 Klass* super = ((InstanceKlass*)k)->java_super();
347 if (super != NULL) {
348 KlassInfoEntry* super_e = cit.lookup(super);
349 assert(super_e != NULL, "could not lookup superclass");
350 e->set_super_index(super_e->index());
351 super_e->add_subclass(e);
352 }
353 }
354
355 // Now we do a depth first traversal of the class hierachry. The class_stack will
356 // maintain the list of classes we still need to process. Start things off
357 // by priming it with java.lang.Object.
358 KlassInfoEntry* jlo_cie = cit.lookup(SystemDictionary::Object_klass());
359 assert(jlo_cie != NULL, "could not lookup java.lang.Object");
360 class_stack.push(jlo_cie);
361
362 // Repeatedly pop the top item off the stack, print its class info,
363 // and push all of its subclasses on to the stack. Do this until there
364 // are no classes left on the stack.
365 //
366 // We also keep track of the stack of superclasses so we know
367 // all the current superclasses for the current class. This is how
368 // we determine the proper indentation when printing the class.
369 long curr_super_index = -1;
370 while (!class_stack.is_empty()) {
371 KlassInfoEntry* curr_cie = class_stack.pop();
372
373 // Make sure super_stack is current with the class we just popped.
374 while (curr_cie->super_index() != curr_super_index) {
375 assert(!super_stack.is_empty(), "super_stack should not be empty");
376 curr_super_index = super_stack.pop()->super_index();
377 }
378
379 print_class(st, curr_cie, &super_stack);
380
381 if (curr_cie->subclasses() != NULL) {
382 // Current class has subclasses, so push all of them onto the stack
383 for (int i = 0; i < curr_cie->subclasses()->length(); i++) {
384 class_stack.push(curr_cie->subclasses()->at(i));
385 }
386 // Add current class to superclass stack.
387 super_stack.push(curr_cie);
388 curr_super_index = curr_cie->index();
389 }
390 }
391
392 st->flush();
393 }
394
395 void KlassHierarchy::print_class(outputStream* st, KlassInfoEntry* cie,
396 Stack <KlassInfoEntry*, mtClass> *super_stack) {
397 ResourceMark rm;
398
399 // print indentation with proper indicators of superclass.
400 StackIterator<KlassInfoEntry*, mtClass> iter(*super_stack);
401 while (!iter.is_empty()) {
402 KlassInfoEntry* super_cie = iter.next();
403 st->print("|");
404 if (iter.is_empty()) {
405 st->print("--");
406 } else {
407 st->print(" ");
408 }
409 }
410
411 // print the class name
412 st->print("%s\n", cie->name());
413 }
414
415 void KlassInfoHisto::print_class_stats(outputStream* st,
416 bool csv_format, const char *columns) {
417 ResourceMark rm;
418 KlassSizeStats sz, sz_sum;
419 int i;
420 julong *col_table = (julong*)(&sz);
421 julong *colsum_table = (julong*)(&sz_sum);
422 int width_table[KlassSizeStats::_num_columns];
423 bool selected[KlassSizeStats::_num_columns];
424
425 _selected_columns = columns;
426
427 memset(&sz_sum, 0, sizeof(sz_sum));
428 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
429 selected[c] = is_selected(name_table[c]);
430 }
431
432 for(i=0; i < elements()->length(); i++) {
433 elements()->at(i)->set_index(i+1);
434 }
435
436 // First iteration is for accumulating stats totals in colsum_table[].
437 // Second iteration is for printing stats for each class.
438 for (int pass=1; pass<=2; pass++) {
439 if (pass == 2) {
440 print_title(st, csv_format, selected, width_table, name_table);
441 }
442 for(i=0; i < elements()->length(); i++) {
443 KlassInfoEntry* e = (KlassInfoEntry*)elements()->at(i);
444 const Klass* k = e->klass();
445
446 // Get the stats for this class
447 memset(&sz, 0, sizeof(sz));
448 sz._inst_count = e->count();
449 sz._inst_bytes = HeapWordSize * e->words();
450 k->collect_statistics(&sz);
451 sz._total_bytes = sz._ro_bytes + sz._rw_bytes;
452
453 if (pass == 1) {
454 // Add the stats for this class to the overall totals
455 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
456 colsum_table[c] += col_table[c];
457 }
458 } else {
459 // Print the stats for this class.
460 if (k->oop_is_instance()) {
461 Klass* super = ((InstanceKlass*)k)->java_super();
462 if (super) {
463 KlassInfoEntry* super_e = _cit->lookup(super);
464 if (super_e) {
465 e->set_super_index(super_e->index());
466 }
467 }
468 }
469
470 if (csv_format) {
471 st->print("%d,%d", e->index(), e->super_index());
472 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
473 if (selected[c]) {st->print("," JULONG_FORMAT, col_table[c]);}
474 }
475 st->print(",%s",e->name());
476 } else {
477 st->print("%5d %5d", e->index(), e->super_index());
478 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
479 if (selected[c]) {print_julong(st, width_table[c], col_table[c]);}
480 }
481 st->print(" %s", e->name());
482 }
483 if (is_selected("ClassLoader")) {
484 ClassLoaderData* loader_data = k->class_loader_data();
485 st->print(",");
486 loader_data->print_value_on(st);
487 }
488 st->cr();
489 }
490 }
491
492 if (pass == 1) {
493 // Calculate the minimum width needed for the column by accounting for the
494 // column header width and the width of the largest value in the column.
495 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
496 width_table[c] = col_width(colsum_table[c], name_table[c]);
497 }
498 }
499 }
500
501 sz_sum._inst_size = 0;
502
503 // Print the column totals.
504 if (csv_format) {
505 st->print(",");
506 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
507 if (selected[c]) {st->print("," JULONG_FORMAT, colsum_table[c]);}
508 }
509 } else {
510 st->print(" ");
511 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
512 if (selected[c]) {print_julong(st, width_table[c], colsum_table[c]);}
513 }
514 st->print(" Total");
515 if (sz_sum._total_bytes > 0) {
516 st->cr();
517 st->print(" ");
518 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
519 if (selected[c]) {
520 switch (c) {
521 case KlassSizeStats::_index_inst_size:
522 case KlassSizeStats::_index_inst_count:
523 case KlassSizeStats::_index_method_count:
524 PRAGMA_DIAG_PUSH
525 PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
526 st->print(str_fmt(width_table[c]), "-");
527 PRAGMA_DIAG_POP
528 break;
529 default:
530 {
531 double perc = (double)(100) * (double)(colsum_table[c]) / (double)sz_sum._total_bytes;
532 PRAGMA_DIAG_PUSH
533 PRAGMA_FORMAT_NONLITERAL_IGNORED_INTERNAL
534 st->print(perc_fmt(width_table[c]), perc);
535 PRAGMA_DIAG_POP
536 }
537 }
538 }
539 }
540 }
541 }
542 st->cr();
543
544 if (!csv_format) {
545 print_title(st, csv_format, selected, width_table, name_table);
546 }
547 }
548
549 julong KlassInfoHisto::annotations_bytes(Array<AnnotationArray*>* p) const {
550 julong bytes = 0;
551 if (p != NULL) {
552 for (int i = 0; i < p->length(); i++) {
553 bytes += count_bytes_array(p->at(i));
554 }
555 bytes += count_bytes_array(p);
556 }
557 return bytes;
558 }
559
560 void KlassInfoHisto::print_histo_on(outputStream* st, bool print_stats,
561 bool csv_format, const char *columns) {
562 if (print_stats) {
563 print_class_stats(st, csv_format, columns);
564 } else {
565 st->print_cr("%s",title());
566 print_elements(st);
567 }
568 }
569
570 class HistoClosure : public KlassInfoClosure {
571 private:
572 KlassInfoHisto* _cih;
573 public:
574 HistoClosure(KlassInfoHisto* cih) : _cih(cih) {}
575
576 void do_cinfo(KlassInfoEntry* cie) {
577 _cih->add(cie);
578 }
579 };
580
581 class RecordInstanceClosure : public ObjectClosure {
582 private:
583 KlassInfoTable* _cit;
584 size_t _missed_count;
585 BoolObjectClosure* _filter;
586 public:
587 RecordInstanceClosure(KlassInfoTable* cit, BoolObjectClosure* filter) :
588 _cit(cit), _missed_count(0), _filter(filter) {}
589
590 void do_object(oop obj) {
591 if (should_visit(obj)) {
592 if (!_cit->record_instance(obj)) {
593 _missed_count++;
594 }
595 }
596 }
597
598 size_t missed_count() { return _missed_count; }
599
600 private:
601 bool should_visit(oop obj) {
602 return _filter == NULL || _filter->do_object_b(obj);
603 }
604 };
605
606 size_t HeapInspection::populate_table(KlassInfoTable* cit, BoolObjectClosure *filter) {
607 ResourceMark rm;
608
609 RecordInstanceClosure ric(cit, filter);
610 Universe::heap()->object_iterate(&ric);
611 return ric.missed_count();
612 }
613
614 void HeapInspection::heap_inspection(outputStream* st) {
615 ResourceMark rm;
616
617 if (_print_help) {
618 for (int c=0; c<KlassSizeStats::_num_columns; c++) {
619 st->print("%s:\n\t", name_table[c]);
620 const int max_col = 60;
621 int col = 0;
622 for (const char *p = help_table[c]; *p; p++,col++) {
623 if (col >= max_col && *p == ' ') {
624 st->print("\n\t");
625 col = 0;
626 } else {
627 st->print("%c", *p);
628 }
629 }
630 st->print_cr(".\n");
631 }
632 return;
633 }
634
635 KlassInfoTable cit(_print_class_stats);
636 if (!cit.allocation_failed()) {
637 // populate table with object allocation info
638 size_t missed_count = populate_table(&cit);
639 if (missed_count != 0) {
640 st->print_cr("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
641 " total instances in data below",
642 missed_count);
643 }
644
645 // Sort and print klass instance info
646 const char *title = "\n"
647 " num #instances #bytes class name\n"
648 "----------------------------------------------";
649 KlassInfoHisto histo(&cit, title);
650 HistoClosure hc(&histo);
651
652 cit.iterate(&hc);
653
654 histo.sort();
655 histo.print_histo_on(st, _print_class_stats, _csv_format, _columns);
656 } else {
657 st->print_cr("WARNING: Ran out of C-heap; histogram not generated");
658 }
659 st->flush();
660 }
661
662 class FindInstanceClosure : public ObjectClosure {
663 private:
664 Klass* _klass;
665 GrowableArray<oop>* _result;
666
667 public:
668 FindInstanceClosure(Klass* k, GrowableArray<oop>* result) : _klass(k), _result(result) {};
669
670 void do_object(oop obj) {
671 if (obj->is_a(_klass)) {
672 _result->append(obj);
673 }
674 }
675 };
676
677 void HeapInspection::find_instances_at_safepoint(Klass* k, GrowableArray<oop>* result) {
678 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
679 assert(Heap_lock->is_locked(), "should have the Heap_lock");
680
681 // Ensure that the heap is parsable
682 Universe::heap()->ensure_parsability(false); // no need to retire TALBs
683
684 // Iterate over objects in the heap
685 FindInstanceClosure fic(k, result);
686 // If this operation encounters a bad object when using CMS,
687 // consider using safe_object_iterate() which avoids metadata
688 // objects that may contain bad references.
689 Universe::heap()->object_iterate(&fic);
690 }