1 /*
2 * Copyright (c) 2000, 2012, 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/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "gc_implementation/shared/collectorCounters.hpp"
31 #include "gc_implementation/shared/gcTraceTime.hpp"
32 #include "gc_implementation/shared/vmGCOperations.hpp"
33 #include "gc_interface/collectedHeap.inline.hpp"
34 #include "memory/compactPermGen.hpp"
35 #include "memory/filemap.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/genCollectedHeap.hpp"
38 #include "memory/genOopClosures.inline.hpp"
39 #include "memory/generation.inline.hpp"
40 #include "memory/generationSpec.hpp"
41 #include "memory/permGen.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "memory/sharedHeap.hpp"
44 #include "memory/space.hpp"
45 #include "oops/oop.inline.hpp"
46 #include "oops/oop.inline2.hpp"
47 #include "runtime/aprofiler.hpp"
48 #include "runtime/biasedLocking.hpp"
49 #include "runtime/fprofiler.hpp"
50 #include "runtime/handles.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/vmThread.hpp"
54 #include "services/memoryService.hpp"
55 #include "services/memTracker.hpp"
56 #include "utilities/vmError.hpp"
57 #include "utilities/workgroup.hpp"
58 #ifndef SERIALGC
59 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
60 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
61 #endif
62
63 GenCollectedHeap* GenCollectedHeap::_gch;
64 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
65
66 // The set of potentially parallel tasks in strong root scanning.
67 enum GCH_process_strong_roots_tasks {
68 // We probably want to parallelize both of these internally, but for now...
69 GCH_PS_younger_gens,
70 // Leave this one last.
71 GCH_PS_NumElements
72 };
73
74 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
75 SharedHeap(policy),
76 _gen_policy(policy),
77 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
78 _full_collections_completed(0)
79 {
80 if (_gen_process_strong_tasks == NULL ||
81 !_gen_process_strong_tasks->valid()) {
82 vm_exit_during_initialization("Failed necessary allocation.");
83 }
84 assert(policy != NULL, "Sanity check");
85 _preloading_shared_classes = false;
86 }
87
88 jint GenCollectedHeap::initialize() {
89 CollectedHeap::pre_initialize();
90
91 int i;
92 _n_gens = gen_policy()->number_of_generations();
93
94 // While there are no constraints in the GC code that HeapWordSize
95 // be any particular value, there are multiple other areas in the
96 // system which believe this to be true (e.g. oop->object_size in some
97 // cases incorrectly returns the size in wordSize units rather than
98 // HeapWordSize).
99 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
100
101 // The heap must be at least as aligned as generations.
102 size_t alignment = Generation::GenGrain;
103
104 _gen_specs = gen_policy()->generations();
105 PermanentGenerationSpec *perm_gen_spec =
106 collector_policy()->permanent_generation();
107
108 // Make sure the sizes are all aligned.
109 for (i = 0; i < _n_gens; i++) {
110 _gen_specs[i]->align(alignment);
111 }
112 perm_gen_spec->align(alignment);
113
114 // If we are dumping the heap, then allocate a wasted block of address
115 // space in order to push the heap to a lower address. This extra
116 // address range allows for other (or larger) libraries to be loaded
117 // without them occupying the space required for the shared spaces.
118
119 if (DumpSharedSpaces) {
120 uintx reserved = 0;
121 uintx block_size = 64*1024*1024;
122 while (reserved < SharedDummyBlockSize) {
123 char* dummy = os::reserve_memory(block_size);
124 reserved += block_size;
125 }
126 }
127
128 // Allocate space for the heap.
129
130 char* heap_address;
131 size_t total_reserved = 0;
132 int n_covered_regions = 0;
133 ReservedSpace heap_rs(0);
134
135 heap_address = allocate(alignment, perm_gen_spec, &total_reserved,
136 &n_covered_regions, &heap_rs);
137
138 if (UseSharedSpaces) {
139 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) {
140 if (heap_rs.is_reserved()) {
141 heap_rs.release();
142 }
143 FileMapInfo* mapinfo = FileMapInfo::current_info();
144 mapinfo->fail_continue("Unable to reserve shared region.");
145 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions,
146 &heap_rs);
147 }
148 }
149
150 if (!heap_rs.is_reserved()) {
151 vm_shutdown_during_initialization(
152 "Could not reserve enough space for object heap");
153 return JNI_ENOMEM;
154 }
155
156 _reserved = MemRegion((HeapWord*)heap_rs.base(),
157 (HeapWord*)(heap_rs.base() + heap_rs.size()));
158
159 // It is important to do this in a way such that concurrent readers can't
160 // temporarily think somethings in the heap. (Seen this happen in asserts.)
161 _reserved.set_word_size(0);
162 _reserved.set_start((HeapWord*)heap_rs.base());
163 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size()
164 - perm_gen_spec->misc_code_size();
165 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
166
167 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
168 set_barrier_set(rem_set()->bs());
169
170 _gch = this;
171
172 for (i = 0; i < _n_gens; i++) {
173 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(),
174 UseSharedSpaces, UseSharedSpaces);
175 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
176 // tag generations in JavaHeap
177 MemTracker::record_virtual_memory_type((address)this_rs.base(), mtJavaHeap);
178 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
179 }
180 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set());
181 // tag PermGen
182 MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtJavaHeap);
183
184 clear_incremental_collection_failed();
185
186 #ifndef SERIALGC
187 // If we are running CMS, create the collector responsible
188 // for collecting the CMS generations.
189 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
190 bool success = create_cms_collector();
191 if (!success) return JNI_ENOMEM;
192 }
193 #endif // SERIALGC
194
195 return JNI_OK;
196 }
197
198
199 char* GenCollectedHeap::allocate(size_t alignment,
200 PermanentGenerationSpec* perm_gen_spec,
201 size_t* _total_reserved,
202 int* _n_covered_regions,
203 ReservedSpace* heap_rs){
204 // Now figure out the total size.
205 size_t total_reserved = 0;
206 int n_covered_regions = 0;
207 const size_t pageSize = UseLargePages ?
208 os::large_page_size() : os::vm_page_size();
209
210 for (int i = 0; i < _n_gens; i++) {
211 total_reserved = add_and_check_overflow(total_reserved, _gen_specs[i]->max_size());
212 n_covered_regions += _gen_specs[i]->n_covered_regions();
213 }
214
215 assert(total_reserved % pageSize == 0,
216 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
217 SIZE_FORMAT, total_reserved, pageSize));
218 total_reserved = add_and_check_overflow(total_reserved, perm_gen_spec->max_size());
219 assert(total_reserved % pageSize == 0,
220 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize="
221 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved,
222 pageSize, perm_gen_spec->max_size()));
223
224 n_covered_regions += perm_gen_spec->n_covered_regions();
225
226 // Add the size of the data area which shares the same reserved area
227 // as the heap, but which is not actually part of the heap.
228 size_t misc = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
229 total_reserved = add_and_check_overflow(total_reserved, misc);
230
231 if (UseLargePages) {
232 assert(total_reserved != 0, "total_reserved cannot be 0");
233 total_reserved = round_up_and_check_overflow(total_reserved, os::large_page_size());
234 }
235
236 // Calculate the address at which the heap must reside in order for
237 // the shared data to be at the required address.
238
239 char* heap_address;
240 if (UseSharedSpaces) {
241
242 // Calculate the address of the first word beyond the heap.
243 FileMapInfo* mapinfo = FileMapInfo::current_info();
244 int lr = CompactingPermGenGen::n_regions - 1;
245 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
246 heap_address = mapinfo->region_base(lr) + capacity;
247
248 // Calculate the address of the first word of the heap.
249 heap_address -= total_reserved;
250 } else {
251 heap_address = NULL; // any address will do.
252 if (UseCompressedOops) {
253 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
254 *_total_reserved = total_reserved;
255 *_n_covered_regions = n_covered_regions;
256 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
257 UseLargePages, heap_address);
258
259 if (heap_address != NULL && !heap_rs->is_reserved()) {
260 // Failed to reserve at specified address - the requested memory
261 // region is taken already, for example, by 'java' launcher.
262 // Try again to reserver heap higher.
263 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
264 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
265 UseLargePages, heap_address);
266
267 if (heap_address != NULL && !heap_rs->is_reserved()) {
268 // Failed to reserve at specified address again - give up.
269 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
270 assert(heap_address == NULL, "");
271 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
272 UseLargePages, heap_address);
273 }
274 }
275 return heap_address;
276 }
277 }
278
279 *_total_reserved = total_reserved;
280 *_n_covered_regions = n_covered_regions;
281 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
282 UseLargePages, heap_address);
283
284 return heap_address;
285 }
286
287
288 void GenCollectedHeap::post_initialize() {
289 SharedHeap::post_initialize();
290 TwoGenerationCollectorPolicy *policy =
291 (TwoGenerationCollectorPolicy *)collector_policy();
292 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
293 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
294 assert(def_new_gen->kind() == Generation::DefNew ||
295 def_new_gen->kind() == Generation::ParNew ||
296 def_new_gen->kind() == Generation::ASParNew,
297 "Wrong generation kind");
298
299 Generation* old_gen = get_gen(1);
300 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
301 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
302 old_gen->kind() == Generation::MarkSweepCompact,
303 "Wrong generation kind");
304
305 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
306 old_gen->capacity(),
307 def_new_gen->from()->capacity());
308 policy->initialize_gc_policy_counters();
309 }
310
311 void GenCollectedHeap::ref_processing_init() {
312 SharedHeap::ref_processing_init();
313 for (int i = 0; i < _n_gens; i++) {
314 _gens[i]->ref_processor_init();
315 }
316 }
317
318 size_t GenCollectedHeap::capacity() const {
319 size_t res = 0;
320 for (int i = 0; i < _n_gens; i++) {
321 res += _gens[i]->capacity();
322 }
323 return res;
324 }
325
326 size_t GenCollectedHeap::used() const {
327 size_t res = 0;
328 for (int i = 0; i < _n_gens; i++) {
329 res += _gens[i]->used();
330 }
331 return res;
332 }
333
334 // Save the "used_region" for generations level and lower,
335 // and, if perm is true, for perm gen.
336 void GenCollectedHeap::save_used_regions(int level, bool perm) {
337 assert(level < _n_gens, "Illegal level parameter");
338 for (int i = level; i >= 0; i--) {
339 _gens[i]->save_used_region();
340 }
341 if (perm) {
342 perm_gen()->save_used_region();
343 }
344 }
345
346 size_t GenCollectedHeap::max_capacity() const {
347 size_t res = 0;
348 for (int i = 0; i < _n_gens; i++) {
349 res += _gens[i]->max_capacity();
350 }
351 return res;
352 }
353
354 // Update the _full_collections_completed counter
355 // at the end of a stop-world full GC.
356 unsigned int GenCollectedHeap::update_full_collections_completed() {
357 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
358 assert(_full_collections_completed <= _total_full_collections,
359 "Can't complete more collections than were started");
360 _full_collections_completed = _total_full_collections;
361 ml.notify_all();
362 return _full_collections_completed;
363 }
364
365 // Update the _full_collections_completed counter, as appropriate,
366 // at the end of a concurrent GC cycle. Note the conditional update
367 // below to allow this method to be called by a concurrent collector
368 // without synchronizing in any manner with the VM thread (which
369 // may already have initiated a STW full collection "concurrently").
370 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
371 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
372 assert((_full_collections_completed <= _total_full_collections) &&
373 (count <= _total_full_collections),
374 "Can't complete more collections than were started");
375 if (count > _full_collections_completed) {
376 _full_collections_completed = count;
377 ml.notify_all();
378 }
379 return _full_collections_completed;
380 }
381
382
383 #ifndef PRODUCT
384 // Override of memory state checking method in CollectedHeap:
385 // Some collectors (CMS for example) can't have badHeapWordVal written
386 // in the first two words of an object. (For instance , in the case of
387 // CMS these words hold state used to synchronize between certain
388 // (concurrent) GC steps and direct allocating mutators.)
389 // The skip_header_HeapWords() method below, allows us to skip
390 // over the requisite number of HeapWord's. Note that (for
391 // generational collectors) this means that those many words are
392 // skipped in each object, irrespective of the generation in which
393 // that object lives. The resultant loss of precision seems to be
394 // harmless and the pain of avoiding that imprecision appears somewhat
395 // higher than we are prepared to pay for such rudimentary debugging
396 // support.
397 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
398 size_t size) {
399 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
400 // We are asked to check a size in HeapWords,
401 // but the memory is mangled in juint words.
402 juint* start = (juint*) (addr + skip_header_HeapWords());
403 juint* end = (juint*) (addr + size);
404 for (juint* slot = start; slot < end; slot += 1) {
405 assert(*slot == badHeapWordVal,
406 "Found non badHeapWordValue in pre-allocation check");
407 }
408 }
409 }
410 #endif
411
412 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
413 bool is_tlab,
414 bool first_only) {
415 HeapWord* res;
416 for (int i = 0; i < _n_gens; i++) {
417 if (_gens[i]->should_allocate(size, is_tlab)) {
418 res = _gens[i]->allocate(size, is_tlab);
419 if (res != NULL) return res;
420 else if (first_only) break;
421 }
422 }
423 // Otherwise...
424 return NULL;
425 }
426
427 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
428 bool* gc_overhead_limit_was_exceeded) {
429 return collector_policy()->mem_allocate_work(size,
430 false /* is_tlab */,
431 gc_overhead_limit_was_exceeded);
432 }
433
434 bool GenCollectedHeap::must_clear_all_soft_refs() {
435 return _gc_cause == GCCause::_last_ditch_collection;
436 }
437
438 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
439 return UseConcMarkSweepGC &&
440 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
441 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
442 }
443
444 void GenCollectedHeap::do_collection(bool full,
445 bool clear_all_soft_refs,
446 size_t size,
447 bool is_tlab,
448 int max_level) {
449 bool prepared_for_verification = false;
450 ResourceMark rm;
451 DEBUG_ONLY(Thread* my_thread = Thread::current();)
452
453 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
454 assert(my_thread->is_VM_thread() ||
455 my_thread->is_ConcurrentGC_thread(),
456 "incorrect thread type capability");
457 assert(Heap_lock->is_locked(),
458 "the requesting thread should have the Heap_lock");
459 guarantee(!is_gc_active(), "collection is not reentrant");
460 assert(max_level < n_gens(), "sanity check");
461
462 if (GC_locker::check_active_before_gc()) {
463 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
464 }
465
466 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
467 collector_policy()->should_clear_all_soft_refs();
468
469 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
470
471 const size_t perm_prev_used = perm_gen()->used();
472
473 print_heap_before_gc();
474
475 {
476 FlagSetting fl(_is_gc_active, true);
477
478 bool complete = full && (max_level == (n_gens()-1));
479 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
480 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
481 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL);
482
483 gc_prologue(complete);
484 increment_total_collections(complete);
485
486 size_t gch_prev_used = used();
487
488 int starting_level = 0;
489 if (full) {
490 // Search for the oldest generation which will collect all younger
491 // generations, and start collection loop there.
492 for (int i = max_level; i >= 0; i--) {
493 if (_gens[i]->full_collects_younger_generations()) {
494 starting_level = i;
495 break;
496 }
497 }
498 }
499
500 bool must_restore_marks_for_biased_locking = false;
501
502 int max_level_collected = starting_level;
503 for (int i = starting_level; i <= max_level; i++) {
504 if (_gens[i]->should_collect(full, size, is_tlab)) {
505 if (i == n_gens() - 1) { // a major collection is to happen
506 if (!complete) {
507 // The full_collections increment was missed above.
508 increment_total_full_collections();
509 }
510 pre_full_gc_dump(NULL); // do any pre full gc dumps
511 }
512 // Timer for individual generations. Last argument is false: no CR
513 // FIXME: We should try to start the timing earlier to cover more of the GC pause
514 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL);
515 TraceCollectorStats tcs(_gens[i]->counters());
516 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
517
518 size_t prev_used = _gens[i]->used();
519 _gens[i]->stat_record()->invocations++;
520 _gens[i]->stat_record()->accumulated_time.start();
521
522 // Must be done anew before each collection because
523 // a previous collection will do mangling and will
524 // change top of some spaces.
525 record_gen_tops_before_GC();
526
527 if (PrintGC && Verbose) {
528 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
529 i,
530 _gens[i]->stat_record()->invocations,
531 size*HeapWordSize);
532 }
533
534 if (VerifyBeforeGC && i >= VerifyGCLevel &&
535 total_collections() >= VerifyGCStartAt) {
536 HandleMark hm; // Discard invalid handles created during verification
537 if (!prepared_for_verification) {
538 prepare_for_verify();
539 prepared_for_verification = true;
540 }
541 gclog_or_tty->print(" VerifyBeforeGC:");
542 Universe::verify();
543 }
544 COMPILER2_PRESENT(DerivedPointerTable::clear());
545
546 if (!must_restore_marks_for_biased_locking &&
547 _gens[i]->performs_in_place_marking()) {
548 // We perform this mark word preservation work lazily
549 // because it's only at this point that we know whether we
550 // absolutely have to do it; we want to avoid doing it for
551 // scavenge-only collections where it's unnecessary
552 must_restore_marks_for_biased_locking = true;
553 BiasedLocking::preserve_marks();
554 }
555
556 // Do collection work
557 {
558 // Note on ref discovery: For what appear to be historical reasons,
559 // GCH enables and disabled (by enqueing) refs discovery.
560 // In the future this should be moved into the generation's
561 // collect method so that ref discovery and enqueueing concerns
562 // are local to a generation. The collect method could return
563 // an appropriate indication in the case that notification on
564 // the ref lock was needed. This will make the treatment of
565 // weak refs more uniform (and indeed remove such concerns
566 // from GCH). XXX
567
568 HandleMark hm; // Discard invalid handles created during gc
569 save_marks(); // save marks for all gens
570 // We want to discover references, but not process them yet.
571 // This mode is disabled in process_discovered_references if the
572 // generation does some collection work, or in
573 // enqueue_discovered_references if the generation returns
574 // without doing any work.
575 ReferenceProcessor* rp = _gens[i]->ref_processor();
576 // If the discovery of ("weak") refs in this generation is
577 // atomic wrt other collectors in this configuration, we
578 // are guaranteed to have empty discovered ref lists.
579 if (rp->discovery_is_atomic()) {
580 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
581 rp->setup_policy(do_clear_all_soft_refs);
582 } else {
583 // collect() below will enable discovery as appropriate
584 }
585 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
586 if (!rp->enqueuing_is_done()) {
587 rp->enqueue_discovered_references();
588 } else {
589 rp->set_enqueuing_is_done(false);
590 }
591 rp->verify_no_references_recorded();
592 }
593 max_level_collected = i;
594
595 // Determine if allocation request was met.
596 if (size > 0) {
597 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
598 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
599 size = 0;
600 }
601 }
602 }
603
604 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
605
606 _gens[i]->stat_record()->accumulated_time.stop();
607
608 update_gc_stats(i, full);
609
610 if (VerifyAfterGC && i >= VerifyGCLevel &&
611 total_collections() >= VerifyGCStartAt) {
612 HandleMark hm; // Discard invalid handles created during verification
613 gclog_or_tty->print(" VerifyAfterGC:");
614 Universe::verify();
615 }
616
617 if (PrintGCDetails) {
618 gclog_or_tty->print(":");
619 _gens[i]->print_heap_change(prev_used);
620 }
621 }
622 }
623
624 // Update "complete" boolean wrt what actually transpired --
625 // for instance, a promotion failure could have led to
626 // a whole heap collection.
627 complete = complete || (max_level_collected == n_gens() - 1);
628
629 if (complete) { // We did a "major" collection
630 // FIXME: See comment at pre_full_gc_dump call
631 post_full_gc_dump(NULL); // do any post full gc dumps
632 }
633
634 if (PrintGCDetails) {
635 print_heap_change(gch_prev_used);
636
637 // Print perm gen info for full GC with PrintGCDetails flag.
638 if (complete) {
639 print_perm_heap_change(perm_prev_used);
640 }
641 }
642
643 for (int j = max_level_collected; j >= 0; j -= 1) {
644 // Adjust generation sizes.
645 _gens[j]->compute_new_size();
646 }
647
648 if (complete) {
649 // Ask the permanent generation to adjust size for full collections
650 perm()->compute_new_size();
651 update_full_collections_completed();
652 }
653
654 // Track memory usage and detect low memory after GC finishes
655 MemoryService::track_memory_usage();
656
657 gc_epilogue(complete);
658
659 if (must_restore_marks_for_biased_locking) {
660 BiasedLocking::restore_marks();
661 }
662 }
663
664 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
665 AdaptiveSizePolicyOutput(sp, total_collections());
666
667 print_heap_after_gc();
668
669 #ifdef TRACESPINNING
670 ParallelTaskTerminator::print_termination_counts();
671 #endif
672 }
673
674 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
675 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
676 }
677
678 void GenCollectedHeap::set_par_threads(uint t) {
679 SharedHeap::set_par_threads(t);
680 _gen_process_strong_tasks->set_n_threads(t);
681 }
682
683 void GenCollectedHeap::
684 gen_process_strong_roots(int level,
685 bool younger_gens_as_roots,
686 bool activate_scope,
687 bool collecting_perm_gen,
688 SharedHeap::ScanningOption so,
689 OopsInGenClosure* not_older_gens,
690 bool do_code_roots,
691 OopsInGenClosure* older_gens) {
692 // General strong roots.
693
694 if (!do_code_roots) {
695 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
696 not_older_gens, NULL, older_gens);
697 } else {
698 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
699 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
700 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
701 not_older_gens, &code_roots, older_gens);
702 }
703
704 if (younger_gens_as_roots) {
705 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
706 for (int i = 0; i < level; i++) {
707 not_older_gens->set_generation(_gens[i]);
708 _gens[i]->oop_iterate(not_older_gens);
709 }
710 not_older_gens->reset_generation();
711 }
712 }
713 // When collection is parallel, all threads get to cooperate to do
714 // older-gen scanning.
715 for (int i = level+1; i < _n_gens; i++) {
716 older_gens->set_generation(_gens[i]);
717 rem_set()->younger_refs_iterate(_gens[i], older_gens);
718 older_gens->reset_generation();
719 }
720
721 _gen_process_strong_tasks->all_tasks_completed();
722 }
723
724 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
725 CodeBlobClosure* code_roots,
726 OopClosure* non_root_closure) {
727 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
728 // "Local" "weak" refs
729 for (int i = 0; i < _n_gens; i++) {
730 _gens[i]->ref_processor()->weak_oops_do(root_closure);
731 }
732 }
733
734 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
735 void GenCollectedHeap:: \
736 oop_since_save_marks_iterate(int level, \
737 OopClosureType* cur, \
738 OopClosureType* older) { \
739 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
740 for (int i = level+1; i < n_gens(); i++) { \
741 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
742 } \
743 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
744 }
745
746 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
747
748 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
749
750 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
751 for (int i = level; i < _n_gens; i++) {
752 if (!_gens[i]->no_allocs_since_save_marks()) return false;
753 }
754 return perm_gen()->no_allocs_since_save_marks();
755 }
756
757 bool GenCollectedHeap::supports_inline_contig_alloc() const {
758 return _gens[0]->supports_inline_contig_alloc();
759 }
760
761 HeapWord** GenCollectedHeap::top_addr() const {
762 return _gens[0]->top_addr();
763 }
764
765 HeapWord** GenCollectedHeap::end_addr() const {
766 return _gens[0]->end_addr();
767 }
768
769 size_t GenCollectedHeap::unsafe_max_alloc() {
770 return _gens[0]->unsafe_max_alloc_nogc();
771 }
772
773 // public collection interfaces
774
775 void GenCollectedHeap::collect(GCCause::Cause cause) {
776 if (should_do_concurrent_full_gc(cause)) {
777 #ifndef SERIALGC
778 // mostly concurrent full collection
779 collect_mostly_concurrent(cause);
780 #else // SERIALGC
781 ShouldNotReachHere();
782 #endif // SERIALGC
783 } else {
784 #ifdef ASSERT
785 if (cause == GCCause::_scavenge_alot) {
786 // minor collection only
787 collect(cause, 0);
788 } else {
789 // Stop-the-world full collection
790 collect(cause, n_gens() - 1);
791 }
792 #else
793 // Stop-the-world full collection
794 collect(cause, n_gens() - 1);
795 #endif
796 }
797 }
798
799 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
800 // The caller doesn't have the Heap_lock
801 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
802 MutexLocker ml(Heap_lock);
803 collect_locked(cause, max_level);
804 }
805
806 // This interface assumes that it's being called by the
807 // vm thread. It collects the heap assuming that the
808 // heap lock is already held and that we are executing in
809 // the context of the vm thread.
810 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
811 assert(Thread::current()->is_VM_thread(), "Precondition#1");
812 assert(Heap_lock->is_locked(), "Precondition#2");
813 GCCauseSetter gcs(this, cause);
814 switch (cause) {
815 case GCCause::_heap_inspection:
816 case GCCause::_heap_dump: {
817 HandleMark hm;
818 do_full_collection(false, // don't clear all soft refs
819 n_gens() - 1);
820 break;
821 }
822 default: // XXX FIX ME
823 ShouldNotReachHere(); // Unexpected use of this function
824 }
825 }
826
827 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
828 // The caller has the Heap_lock
829 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
830 collect_locked(cause, n_gens() - 1);
831 }
832
833 // this is the private collection interface
834 // The Heap_lock is expected to be held on entry.
835
836 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
837 if (_preloading_shared_classes) {
838 report_out_of_shared_space(SharedPermGen);
839 }
840 // Read the GC count while holding the Heap_lock
841 unsigned int gc_count_before = total_collections();
842 unsigned int full_gc_count_before = total_full_collections();
843 {
844 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
845 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
846 cause, max_level);
847 VMThread::execute(&op);
848 }
849 }
850
851 #ifndef SERIALGC
852 bool GenCollectedHeap::create_cms_collector() {
853
854 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
855 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
856 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
857 "Unexpected generation kinds");
858 // Skip two header words in the block content verification
859 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
860 CMSCollector* collector = new CMSCollector(
861 (ConcurrentMarkSweepGeneration*)_gens[1],
862 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
863 _rem_set->as_CardTableRS(),
864 (ConcurrentMarkSweepPolicy*) collector_policy());
865
866 if (collector == NULL || !collector->completed_initialization()) {
867 if (collector) {
868 delete collector; // Be nice in embedded situation
869 }
870 vm_shutdown_during_initialization("Could not create CMS collector");
871 return false;
872 }
873 return true; // success
874 }
875
876 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
877 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
878
879 MutexLocker ml(Heap_lock);
880 // Read the GC counts while holding the Heap_lock
881 unsigned int full_gc_count_before = total_full_collections();
882 unsigned int gc_count_before = total_collections();
883 {
884 MutexUnlocker mu(Heap_lock);
885 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
886 VMThread::execute(&op);
887 }
888 }
889 #endif // SERIALGC
890
891
892 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
893 int max_level) {
894 int local_max_level;
895 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
896 gc_cause() == GCCause::_gc_locker) {
897 local_max_level = 0;
898 } else {
899 local_max_level = max_level;
900 }
901
902 do_collection(true /* full */,
903 clear_all_soft_refs /* clear_all_soft_refs */,
904 0 /* size */,
905 false /* is_tlab */,
906 local_max_level /* max_level */);
907 // Hack XXX FIX ME !!!
908 // A scavenge may not have been attempted, or may have
909 // been attempted and failed, because the old gen was too full
910 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
911 incremental_collection_will_fail(false /* don't consult_young */)) {
912 if (PrintGCDetails) {
913 gclog_or_tty->print_cr("GC locker: Trying a full collection "
914 "because scavenge failed");
915 }
916 // This time allow the old gen to be collected as well
917 do_collection(true /* full */,
918 clear_all_soft_refs /* clear_all_soft_refs */,
919 0 /* size */,
920 false /* is_tlab */,
921 n_gens() - 1 /* max_level */);
922 }
923 }
924
925 bool GenCollectedHeap::is_in_young(oop p) {
926 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
927 assert(result == _gens[0]->is_in_reserved(p),
928 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, (void*)p));
929 return result;
930 }
931
932 // Returns "TRUE" iff "p" points into the committed areas of the heap.
933 bool GenCollectedHeap::is_in(const void* p) const {
934 #ifndef ASSERT
935 guarantee(VerifyBeforeGC ||
936 VerifyDuringGC ||
937 VerifyBeforeExit ||
938 PrintAssembly ||
939 tty->count() != 0 || // already printing
940 VerifyAfterGC ||
941 VMError::fatal_error_in_progress(), "too expensive");
942
943 #endif
944 // This might be sped up with a cache of the last generation that
945 // answered yes.
946 for (int i = 0; i < _n_gens; i++) {
947 if (_gens[i]->is_in(p)) return true;
948 }
949 if (_perm_gen->as_gen()->is_in(p)) return true;
950 // Otherwise...
951 return false;
952 }
953
954 #ifdef ASSERT
955 // Don't implement this by using is_in_young(). This method is used
956 // in some cases to check that is_in_young() is correct.
957 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
958 assert(is_in_reserved(p) || p == NULL,
959 "Does not work if address is non-null and outside of the heap");
960 // The order of the generations is young (low addr), old, perm (high addr)
961 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
962 }
963 #endif
964
965 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
966 for (int i = 0; i < _n_gens; i++) {
967 _gens[i]->oop_iterate(cl);
968 }
969 }
970
971 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
972 for (int i = 0; i < _n_gens; i++) {
973 _gens[i]->oop_iterate(mr, cl);
974 }
975 }
976
977 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
978 for (int i = 0; i < _n_gens; i++) {
979 _gens[i]->object_iterate(cl);
980 }
981 perm_gen()->object_iterate(cl);
982 }
983
984 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
985 for (int i = 0; i < _n_gens; i++) {
986 _gens[i]->safe_object_iterate(cl);
987 }
988 perm_gen()->safe_object_iterate(cl);
989 }
990
991 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
992 for (int i = 0; i < _n_gens; i++) {
993 _gens[i]->object_iterate_since_last_GC(cl);
994 }
995 }
996
997 Space* GenCollectedHeap::space_containing(const void* addr) const {
998 for (int i = 0; i < _n_gens; i++) {
999 Space* res = _gens[i]->space_containing(addr);
1000 if (res != NULL) return res;
1001 }
1002 Space* res = perm_gen()->space_containing(addr);
1003 if (res != NULL) return res;
1004 // Otherwise...
1005 assert(false, "Could not find containing space");
1006 return NULL;
1007 }
1008
1009
1010 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1011 assert(is_in_reserved(addr), "block_start of address outside of heap");
1012 for (int i = 0; i < _n_gens; i++) {
1013 if (_gens[i]->is_in_reserved(addr)) {
1014 assert(_gens[i]->is_in(addr),
1015 "addr should be in allocated part of generation");
1016 return _gens[i]->block_start(addr);
1017 }
1018 }
1019 if (perm_gen()->is_in_reserved(addr)) {
1020 assert(perm_gen()->is_in(addr),
1021 "addr should be in allocated part of perm gen");
1022 return perm_gen()->block_start(addr);
1023 }
1024 assert(false, "Some generation should contain the address");
1025 return NULL;
1026 }
1027
1028 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1029 assert(is_in_reserved(addr), "block_size of address outside of heap");
1030 for (int i = 0; i < _n_gens; i++) {
1031 if (_gens[i]->is_in_reserved(addr)) {
1032 assert(_gens[i]->is_in(addr),
1033 "addr should be in allocated part of generation");
1034 return _gens[i]->block_size(addr);
1035 }
1036 }
1037 if (perm_gen()->is_in_reserved(addr)) {
1038 assert(perm_gen()->is_in(addr),
1039 "addr should be in allocated part of perm gen");
1040 return perm_gen()->block_size(addr);
1041 }
1042 assert(false, "Some generation should contain the address");
1043 return 0;
1044 }
1045
1046 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1047 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1048 assert(block_start(addr) == addr, "addr must be a block start");
1049 for (int i = 0; i < _n_gens; i++) {
1050 if (_gens[i]->is_in_reserved(addr)) {
1051 return _gens[i]->block_is_obj(addr);
1052 }
1053 }
1054 if (perm_gen()->is_in_reserved(addr)) {
1055 return perm_gen()->block_is_obj(addr);
1056 }
1057 assert(false, "Some generation should contain the address");
1058 return false;
1059 }
1060
1061 bool GenCollectedHeap::supports_tlab_allocation() const {
1062 for (int i = 0; i < _n_gens; i += 1) {
1063 if (_gens[i]->supports_tlab_allocation()) {
1064 return true;
1065 }
1066 }
1067 return false;
1068 }
1069
1070 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1071 size_t result = 0;
1072 for (int i = 0; i < _n_gens; i += 1) {
1073 if (_gens[i]->supports_tlab_allocation()) {
1074 result += _gens[i]->tlab_capacity();
1075 }
1076 }
1077 return result;
1078 }
1079
1080 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1081 size_t result = 0;
1082 for (int i = 0; i < _n_gens; i += 1) {
1083 if (_gens[i]->supports_tlab_allocation()) {
1084 result += _gens[i]->unsafe_max_tlab_alloc();
1085 }
1086 }
1087 return result;
1088 }
1089
1090 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1091 bool gc_overhead_limit_was_exceeded;
1092 return collector_policy()->mem_allocate_work(size /* size */,
1093 true /* is_tlab */,
1094 &gc_overhead_limit_was_exceeded);
1095 }
1096
1097 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1098 // from the list headed by "*prev_ptr".
1099 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1100 bool first = true;
1101 size_t min_size = 0; // "first" makes this conceptually infinite.
1102 ScratchBlock **smallest_ptr, *smallest;
1103 ScratchBlock *cur = *prev_ptr;
1104 while (cur) {
1105 assert(*prev_ptr == cur, "just checking");
1106 if (first || cur->num_words < min_size) {
1107 smallest_ptr = prev_ptr;
1108 smallest = cur;
1109 min_size = smallest->num_words;
1110 first = false;
1111 }
1112 prev_ptr = &cur->next;
1113 cur = cur->next;
1114 }
1115 smallest = *smallest_ptr;
1116 *smallest_ptr = smallest->next;
1117 return smallest;
1118 }
1119
1120 // Sort the scratch block list headed by res into decreasing size order,
1121 // and set "res" to the result.
1122 static void sort_scratch_list(ScratchBlock*& list) {
1123 ScratchBlock* sorted = NULL;
1124 ScratchBlock* unsorted = list;
1125 while (unsorted) {
1126 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1127 smallest->next = sorted;
1128 sorted = smallest;
1129 }
1130 list = sorted;
1131 }
1132
1133 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1134 size_t max_alloc_words) {
1135 ScratchBlock* res = NULL;
1136 for (int i = 0; i < _n_gens; i++) {
1137 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1138 }
1139 sort_scratch_list(res);
1140 return res;
1141 }
1142
1143 void GenCollectedHeap::release_scratch() {
1144 for (int i = 0; i < _n_gens; i++) {
1145 _gens[i]->reset_scratch();
1146 }
1147 }
1148
1149 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1150 void do_generation(Generation* gen) {
1151 gen->prepare_for_verify();
1152 }
1153 };
1154
1155 void GenCollectedHeap::prepare_for_verify() {
1156 ensure_parsability(false); // no need to retire TLABs
1157 GenPrepareForVerifyClosure blk;
1158 generation_iterate(&blk, false);
1159 perm_gen()->prepare_for_verify();
1160 }
1161
1162
1163 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1164 bool old_to_young) {
1165 if (old_to_young) {
1166 for (int i = _n_gens-1; i >= 0; i--) {
1167 cl->do_generation(_gens[i]);
1168 }
1169 } else {
1170 for (int i = 0; i < _n_gens; i++) {
1171 cl->do_generation(_gens[i]);
1172 }
1173 }
1174 }
1175
1176 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1177 for (int i = 0; i < _n_gens; i++) {
1178 _gens[i]->space_iterate(cl, true);
1179 }
1180 perm_gen()->space_iterate(cl, true);
1181 }
1182
1183 bool GenCollectedHeap::is_maximal_no_gc() const {
1184 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1185 if (!_gens[i]->is_maximal_no_gc()) {
1186 return false;
1187 }
1188 }
1189 return true;
1190 }
1191
1192 void GenCollectedHeap::save_marks() {
1193 for (int i = 0; i < _n_gens; i++) {
1194 _gens[i]->save_marks();
1195 }
1196 perm_gen()->save_marks();
1197 }
1198
1199 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1200 for (int i = 0; i <= collectedGen; i++) {
1201 _gens[i]->compute_new_size();
1202 }
1203 }
1204
1205 GenCollectedHeap* GenCollectedHeap::heap() {
1206 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1207 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1208 return _gch;
1209 }
1210
1211
1212 void GenCollectedHeap::prepare_for_compaction() {
1213 Generation* scanning_gen = _gens[_n_gens-1];
1214 // Start by compacting into same gen.
1215 CompactPoint cp(scanning_gen, NULL, NULL);
1216 while (scanning_gen != NULL) {
1217 scanning_gen->prepare_for_compaction(&cp);
1218 scanning_gen = prev_gen(scanning_gen);
1219 }
1220 }
1221
1222 GCStats* GenCollectedHeap::gc_stats(int level) const {
1223 return _gens[level]->gc_stats();
1224 }
1225
1226 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1227 if (!silent) {
1228 gclog_or_tty->print("permgen ");
1229 }
1230 perm_gen()->verify();
1231 for (int i = _n_gens-1; i >= 0; i--) {
1232 Generation* g = _gens[i];
1233 if (!silent) {
1234 gclog_or_tty->print(g->name());
1235 gclog_or_tty->print(" ");
1236 }
1237 g->verify();
1238 }
1239 if (!silent) {
1240 gclog_or_tty->print("remset ");
1241 }
1242 rem_set()->verify();
1243 }
1244
1245 void GenCollectedHeap::print_on(outputStream* st) const {
1246 for (int i = 0; i < _n_gens; i++) {
1247 _gens[i]->print_on(st);
1248 }
1249 perm_gen()->print_on(st);
1250 }
1251
1252 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1253 if (workers() != NULL) {
1254 workers()->threads_do(tc);
1255 }
1256 #ifndef SERIALGC
1257 if (UseConcMarkSweepGC) {
1258 ConcurrentMarkSweepThread::threads_do(tc);
1259 }
1260 #endif // SERIALGC
1261 }
1262
1263 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1264 #ifndef SERIALGC
1265 if (UseParNewGC) {
1266 workers()->print_worker_threads_on(st);
1267 }
1268 if (UseConcMarkSweepGC) {
1269 ConcurrentMarkSweepThread::print_all_on(st);
1270 }
1271 #endif // SERIALGC
1272 }
1273
1274 void GenCollectedHeap::print_tracing_info() const {
1275 if (TraceGen0Time) {
1276 get_gen(0)->print_summary_info();
1277 }
1278 if (TraceGen1Time) {
1279 get_gen(1)->print_summary_info();
1280 }
1281 }
1282
1283 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1284 if (PrintGCDetails && Verbose) {
1285 gclog_or_tty->print(" " SIZE_FORMAT
1286 "->" SIZE_FORMAT
1287 "(" SIZE_FORMAT ")",
1288 prev_used, used(), capacity());
1289 } else {
1290 gclog_or_tty->print(" " SIZE_FORMAT "K"
1291 "->" SIZE_FORMAT "K"
1292 "(" SIZE_FORMAT "K)",
1293 prev_used / K, used() / K, capacity() / K);
1294 }
1295 }
1296
1297 //New method to print perm gen info with PrintGCDetails flag
1298 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1299 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1300 perm_gen()->print_heap_change(perm_prev_used);
1301 gclog_or_tty->print("]");
1302 }
1303
1304 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1305 private:
1306 bool _full;
1307 public:
1308 void do_generation(Generation* gen) {
1309 gen->gc_prologue(_full);
1310 }
1311 GenGCPrologueClosure(bool full) : _full(full) {};
1312 };
1313
1314 void GenCollectedHeap::gc_prologue(bool full) {
1315 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1316
1317 always_do_update_barrier = false;
1318 // Fill TLAB's and such
1319 CollectedHeap::accumulate_statistics_all_tlabs();
1320 ensure_parsability(true); // retire TLABs
1321
1322 // Call allocation profiler
1323 AllocationProfiler::iterate_since_last_gc();
1324 // Walk generations
1325 GenGCPrologueClosure blk(full);
1326 generation_iterate(&blk, false); // not old-to-young.
1327 perm_gen()->gc_prologue(full);
1328 };
1329
1330 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1331 private:
1332 bool _full;
1333 public:
1334 void do_generation(Generation* gen) {
1335 gen->gc_epilogue(_full);
1336 }
1337 GenGCEpilogueClosure(bool full) : _full(full) {};
1338 };
1339
1340 void GenCollectedHeap::gc_epilogue(bool full) {
1341 #ifdef COMPILER2
1342 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1343 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1344 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1345 #endif /* COMPILER2 */
1346
1347 resize_all_tlabs();
1348
1349 GenGCEpilogueClosure blk(full);
1350 generation_iterate(&blk, false); // not old-to-young.
1351 perm_gen()->gc_epilogue(full);
1352
1353 if (!CleanChunkPoolAsync) {
1354 Chunk::clean_chunk_pool();
1355 }
1356
1357 always_do_update_barrier = UseConcMarkSweepGC;
1358 };
1359
1360 #ifndef PRODUCT
1361 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1362 private:
1363 public:
1364 void do_generation(Generation* gen) {
1365 gen->record_spaces_top();
1366 }
1367 };
1368
1369 void GenCollectedHeap::record_gen_tops_before_GC() {
1370 if (ZapUnusedHeapArea) {
1371 GenGCSaveTopsBeforeGCClosure blk;
1372 generation_iterate(&blk, false); // not old-to-young.
1373 perm_gen()->record_spaces_top();
1374 }
1375 }
1376 #endif // not PRODUCT
1377
1378 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1379 public:
1380 void do_generation(Generation* gen) {
1381 gen->ensure_parsability();
1382 }
1383 };
1384
1385 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1386 CollectedHeap::ensure_parsability(retire_tlabs);
1387 GenEnsureParsabilityClosure ep_cl;
1388 generation_iterate(&ep_cl, false);
1389 perm_gen()->ensure_parsability();
1390 }
1391
1392 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1393 oop obj,
1394 size_t obj_size) {
1395 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1396 HeapWord* result = NULL;
1397
1398 // First give each higher generation a chance to allocate the promoted object.
1399 Generation* allocator = next_gen(gen);
1400 if (allocator != NULL) {
1401 do {
1402 result = allocator->allocate(obj_size, false);
1403 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1404 }
1405
1406 if (result == NULL) {
1407 // Then give gen and higher generations a chance to expand and allocate the
1408 // object.
1409 do {
1410 result = gen->expand_and_allocate(obj_size, false);
1411 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1412 }
1413
1414 if (result != NULL) {
1415 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1416 }
1417 return oop(result);
1418 }
1419
1420 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1421 jlong _time; // in ms
1422 jlong _now; // in ms
1423
1424 public:
1425 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1426
1427 jlong time() { return _time; }
1428
1429 void do_generation(Generation* gen) {
1430 _time = MIN2(_time, gen->time_of_last_gc(_now));
1431 }
1432 };
1433
1434 jlong GenCollectedHeap::millis_since_last_gc() {
1435 // We need a monotonically non-deccreasing time in ms but
1436 // os::javaTimeMillis() does not guarantee monotonicity.
1437 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1438 GenTimeOfLastGCClosure tolgc_cl(now);
1439 // iterate over generations getting the oldest
1440 // time that a generation was collected
1441 generation_iterate(&tolgc_cl, false);
1442 tolgc_cl.do_generation(perm_gen());
1443
1444 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1445 // provided the underlying platform provides such a time source
1446 // (and it is bug free). So we still have to guard against getting
1447 // back a time later than 'now'.
1448 jlong retVal = now - tolgc_cl.time();
1449 if (retVal < 0) {
1450 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);)
1451 return 0;
1452 }
1453 return retVal;
1454 }