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 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
481 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
482 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL);
483
484 gc_prologue(complete);
485 increment_total_collections(complete);
486
487 size_t gch_prev_used = used();
488
489 int starting_level = 0;
490 if (full) {
491 // Search for the oldest generation which will collect all younger
492 // generations, and start collection loop there.
493 for (int i = max_level; i >= 0; i--) {
494 if (_gens[i]->full_collects_younger_generations()) {
495 starting_level = i;
496 break;
497 }
498 }
499 }
500
501 bool must_restore_marks_for_biased_locking = false;
502
503 int max_level_collected = starting_level;
504 for (int i = starting_level; i <= max_level; i++) {
505 if (_gens[i]->should_collect(full, size, is_tlab)) {
506 if (i == n_gens() - 1) { // a major collection is to happen
507 if (!complete) {
508 // The full_collections increment was missed above.
509 increment_total_full_collections();
510 }
511 pre_full_gc_dump(NULL); // do any pre full gc dumps
512 }
513 // Timer for individual generations. Last argument is false: no CR
514 // FIXME: We should try to start the timing earlier to cover more of the GC pause
515 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL);
516 TraceCollectorStats tcs(_gens[i]->counters());
517 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
518
519 size_t prev_used = _gens[i]->used();
520 _gens[i]->stat_record()->invocations++;
521 _gens[i]->stat_record()->accumulated_time.start();
522
523 // Must be done anew before each collection because
524 // a previous collection will do mangling and will
525 // change top of some spaces.
526 record_gen_tops_before_GC();
527
528 if (PrintGC && Verbose) {
529 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
530 i,
531 _gens[i]->stat_record()->invocations,
532 size*HeapWordSize);
533 }
534
535 if (VerifyBeforeGC && i >= VerifyGCLevel &&
536 total_collections() >= VerifyGCStartAt) {
537 HandleMark hm; // Discard invalid handles created during verification
538 if (!prepared_for_verification) {
539 prepare_for_verify();
540 prepared_for_verification = true;
541 }
542 gclog_or_tty->print(" VerifyBeforeGC:");
543 Universe::verify();
544 }
545 COMPILER2_PRESENT(DerivedPointerTable::clear());
546
547 if (!must_restore_marks_for_biased_locking &&
548 _gens[i]->performs_in_place_marking()) {
549 // We perform this mark word preservation work lazily
550 // because it's only at this point that we know whether we
551 // absolutely have to do it; we want to avoid doing it for
552 // scavenge-only collections where it's unnecessary
553 must_restore_marks_for_biased_locking = true;
554 BiasedLocking::preserve_marks();
555 }
556
557 // Do collection work
558 {
559 // Note on ref discovery: For what appear to be historical reasons,
560 // GCH enables and disabled (by enqueing) refs discovery.
561 // In the future this should be moved into the generation's
562 // collect method so that ref discovery and enqueueing concerns
563 // are local to a generation. The collect method could return
564 // an appropriate indication in the case that notification on
565 // the ref lock was needed. This will make the treatment of
566 // weak refs more uniform (and indeed remove such concerns
567 // from GCH). XXX
568
569 HandleMark hm; // Discard invalid handles created during gc
570 save_marks(); // save marks for all gens
571 // We want to discover references, but not process them yet.
572 // This mode is disabled in process_discovered_references if the
573 // generation does some collection work, or in
574 // enqueue_discovered_references if the generation returns
575 // without doing any work.
576 ReferenceProcessor* rp = _gens[i]->ref_processor();
577 // If the discovery of ("weak") refs in this generation is
578 // atomic wrt other collectors in this configuration, we
579 // are guaranteed to have empty discovered ref lists.
580 if (rp->discovery_is_atomic()) {
581 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
582 rp->setup_policy(do_clear_all_soft_refs);
583 } else {
584 // collect() below will enable discovery as appropriate
585 }
586 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
587 if (!rp->enqueuing_is_done()) {
588 rp->enqueue_discovered_references();
589 } else {
590 rp->set_enqueuing_is_done(false);
591 }
592 rp->verify_no_references_recorded();
593 }
594 max_level_collected = i;
595
596 // Determine if allocation request was met.
597 if (size > 0) {
598 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
599 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
600 size = 0;
601 }
602 }
603 }
604
605 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
606
607 _gens[i]->stat_record()->accumulated_time.stop();
608
609 update_gc_stats(i, full);
610
611 if (VerifyAfterGC && i >= VerifyGCLevel &&
612 total_collections() >= VerifyGCStartAt) {
613 HandleMark hm; // Discard invalid handles created during verification
614 gclog_or_tty->print(" VerifyAfterGC:");
615 Universe::verify();
616 }
617
618 if (PrintGCDetails) {
619 gclog_or_tty->print(":");
620 _gens[i]->print_heap_change(prev_used);
621 }
622 }
623 }
624
625 // Update "complete" boolean wrt what actually transpired --
626 // for instance, a promotion failure could have led to
627 // a whole heap collection.
628 complete = complete || (max_level_collected == n_gens() - 1);
629
630 if (complete) { // We did a "major" collection
631 // FIXME: See comment at pre_full_gc_dump call
632 post_full_gc_dump(NULL); // do any post full gc dumps
633 }
634
635 if (PrintGCDetails) {
636 print_heap_change(gch_prev_used);
637
638 // Print perm gen info for full GC with PrintGCDetails flag.
639 if (complete) {
640 print_perm_heap_change(perm_prev_used);
641 }
642 }
643
644 for (int j = max_level_collected; j >= 0; j -= 1) {
645 // Adjust generation sizes.
646 _gens[j]->compute_new_size();
647 }
648
649 if (complete) {
650 // Ask the permanent generation to adjust size for full collections
651 perm()->compute_new_size();
652 update_full_collections_completed();
653 }
654
655 // Track memory usage and detect low memory after GC finishes
656 MemoryService::track_memory_usage();
657
658 gc_epilogue(complete);
659
660 if (must_restore_marks_for_biased_locking) {
661 BiasedLocking::restore_marks();
662 }
663 }
664
665 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
666 AdaptiveSizePolicyOutput(sp, total_collections());
667
668 print_heap_after_gc();
669
670 #ifdef TRACESPINNING
671 ParallelTaskTerminator::print_termination_counts();
672 #endif
673 }
674
675 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
676 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
677 }
678
679 void GenCollectedHeap::set_par_threads(uint t) {
680 SharedHeap::set_par_threads(t);
681 _gen_process_strong_tasks->set_n_threads(t);
682 }
683
684 void GenCollectedHeap::
685 gen_process_strong_roots(int level,
686 bool younger_gens_as_roots,
687 bool activate_scope,
688 bool collecting_perm_gen,
689 SharedHeap::ScanningOption so,
690 OopsInGenClosure* not_older_gens,
691 bool do_code_roots,
692 OopsInGenClosure* older_gens) {
693 // General strong roots.
694
695 if (!do_code_roots) {
696 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
697 not_older_gens, NULL, older_gens);
698 } else {
699 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
700 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
701 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
702 not_older_gens, &code_roots, older_gens);
703 }
704
705 if (younger_gens_as_roots) {
706 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
707 for (int i = 0; i < level; i++) {
708 not_older_gens->set_generation(_gens[i]);
709 _gens[i]->oop_iterate(not_older_gens);
710 }
711 not_older_gens->reset_generation();
712 }
713 }
714 // When collection is parallel, all threads get to cooperate to do
715 // older-gen scanning.
716 for (int i = level+1; i < _n_gens; i++) {
717 older_gens->set_generation(_gens[i]);
718 rem_set()->younger_refs_iterate(_gens[i], older_gens);
719 older_gens->reset_generation();
720 }
721
722 _gen_process_strong_tasks->all_tasks_completed();
723 }
724
725 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
726 CodeBlobClosure* code_roots,
727 OopClosure* non_root_closure) {
728 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
729 // "Local" "weak" refs
730 for (int i = 0; i < _n_gens; i++) {
731 _gens[i]->ref_processor()->weak_oops_do(root_closure);
732 }
733 }
734
735 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
736 void GenCollectedHeap:: \
737 oop_since_save_marks_iterate(int level, \
738 OopClosureType* cur, \
739 OopClosureType* older) { \
740 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
741 for (int i = level+1; i < n_gens(); i++) { \
742 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
743 } \
744 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
745 }
746
747 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
748
749 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
750
751 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
752 for (int i = level; i < _n_gens; i++) {
753 if (!_gens[i]->no_allocs_since_save_marks()) return false;
754 }
755 return perm_gen()->no_allocs_since_save_marks();
756 }
757
758 bool GenCollectedHeap::supports_inline_contig_alloc() const {
759 return _gens[0]->supports_inline_contig_alloc();
760 }
761
762 HeapWord** GenCollectedHeap::top_addr() const {
763 return _gens[0]->top_addr();
764 }
765
766 HeapWord** GenCollectedHeap::end_addr() const {
767 return _gens[0]->end_addr();
768 }
769
770 size_t GenCollectedHeap::unsafe_max_alloc() {
771 return _gens[0]->unsafe_max_alloc_nogc();
772 }
773
774 // public collection interfaces
775
776 void GenCollectedHeap::collect(GCCause::Cause cause) {
777 if (should_do_concurrent_full_gc(cause)) {
778 #ifndef SERIALGC
779 // mostly concurrent full collection
780 collect_mostly_concurrent(cause);
781 #else // SERIALGC
782 ShouldNotReachHere();
783 #endif // SERIALGC
784 } else {
785 #ifdef ASSERT
786 if (cause == GCCause::_scavenge_alot) {
787 // minor collection only
788 collect(cause, 0);
789 } else {
790 // Stop-the-world full collection
791 collect(cause, n_gens() - 1);
792 }
793 #else
794 // Stop-the-world full collection
795 collect(cause, n_gens() - 1);
796 #endif
797 }
798 }
799
800 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
801 // The caller doesn't have the Heap_lock
802 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
803 MutexLocker ml(Heap_lock);
804 collect_locked(cause, max_level);
805 }
806
807 // This interface assumes that it's being called by the
808 // vm thread. It collects the heap assuming that the
809 // heap lock is already held and that we are executing in
810 // the context of the vm thread.
811 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
812 assert(Thread::current()->is_VM_thread(), "Precondition#1");
813 assert(Heap_lock->is_locked(), "Precondition#2");
814 GCCauseSetter gcs(this, cause);
815 switch (cause) {
816 case GCCause::_heap_inspection:
817 case GCCause::_heap_dump: {
818 HandleMark hm;
819 do_full_collection(false, // don't clear all soft refs
820 n_gens() - 1);
821 break;
822 }
823 default: // XXX FIX ME
824 ShouldNotReachHere(); // Unexpected use of this function
825 }
826 }
827
828 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
829 // The caller has the Heap_lock
830 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
831 collect_locked(cause, n_gens() - 1);
832 }
833
834 // this is the private collection interface
835 // The Heap_lock is expected to be held on entry.
836
837 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
838 if (_preloading_shared_classes) {
839 report_out_of_shared_space(SharedPermGen);
840 }
841 // Read the GC count while holding the Heap_lock
842 unsigned int gc_count_before = total_collections();
843 unsigned int full_gc_count_before = total_full_collections();
844 {
845 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
846 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
847 cause, max_level);
848 VMThread::execute(&op);
849 }
850 }
851
852 #ifndef SERIALGC
853 bool GenCollectedHeap::create_cms_collector() {
854
855 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
856 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
857 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
858 "Unexpected generation kinds");
859 // Skip two header words in the block content verification
860 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
861 CMSCollector* collector = new CMSCollector(
862 (ConcurrentMarkSweepGeneration*)_gens[1],
863 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
864 _rem_set->as_CardTableRS(),
865 (ConcurrentMarkSweepPolicy*) collector_policy());
866
867 if (collector == NULL || !collector->completed_initialization()) {
868 if (collector) {
869 delete collector; // Be nice in embedded situation
870 }
871 vm_shutdown_during_initialization("Could not create CMS collector");
872 return false;
873 }
874 return true; // success
875 }
876
877 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
878 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
879
880 MutexLocker ml(Heap_lock);
881 // Read the GC counts while holding the Heap_lock
882 unsigned int full_gc_count_before = total_full_collections();
883 unsigned int gc_count_before = total_collections();
884 {
885 MutexUnlocker mu(Heap_lock);
886 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
887 VMThread::execute(&op);
888 }
889 }
890 #endif // SERIALGC
891
892
893 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
894 int max_level) {
895 int local_max_level;
896 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
897 gc_cause() == GCCause::_gc_locker) {
898 local_max_level = 0;
899 } else {
900 local_max_level = max_level;
901 }
902
903 do_collection(true /* full */,
904 clear_all_soft_refs /* clear_all_soft_refs */,
905 0 /* size */,
906 false /* is_tlab */,
907 local_max_level /* max_level */);
908 // Hack XXX FIX ME !!!
909 // A scavenge may not have been attempted, or may have
910 // been attempted and failed, because the old gen was too full
911 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
912 incremental_collection_will_fail(false /* don't consult_young */)) {
913 if (PrintGCDetails) {
914 gclog_or_tty->print_cr("GC locker: Trying a full collection "
915 "because scavenge failed");
916 }
917 // This time allow the old gen to be collected as well
918 do_collection(true /* full */,
919 clear_all_soft_refs /* clear_all_soft_refs */,
920 0 /* size */,
921 false /* is_tlab */,
922 n_gens() - 1 /* max_level */);
923 }
924 }
925
926 bool GenCollectedHeap::is_in_young(oop p) {
927 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
928 assert(result == _gens[0]->is_in_reserved(p),
929 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, (void*)p));
930 return result;
931 }
932
933 // Returns "TRUE" iff "p" points into the committed areas of the heap.
934 bool GenCollectedHeap::is_in(const void* p) const {
935 #ifndef ASSERT
936 guarantee(VerifyBeforeGC ||
937 VerifyDuringGC ||
938 VerifyBeforeExit ||
939 PrintAssembly ||
940 tty->count() != 0 || // already printing
941 VerifyAfterGC ||
942 VMError::fatal_error_in_progress(), "too expensive");
943
944 #endif
945 // This might be sped up with a cache of the last generation that
946 // answered yes.
947 for (int i = 0; i < _n_gens; i++) {
948 if (_gens[i]->is_in(p)) return true;
949 }
950 if (_perm_gen->as_gen()->is_in(p)) return true;
951 // Otherwise...
952 return false;
953 }
954
955 #ifdef ASSERT
956 // Don't implement this by using is_in_young(). This method is used
957 // in some cases to check that is_in_young() is correct.
958 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
959 assert(is_in_reserved(p) || p == NULL,
960 "Does not work if address is non-null and outside of the heap");
961 // The order of the generations is young (low addr), old, perm (high addr)
962 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
963 }
964 #endif
965
966 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
967 for (int i = 0; i < _n_gens; i++) {
968 _gens[i]->oop_iterate(cl);
969 }
970 }
971
972 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
973 for (int i = 0; i < _n_gens; i++) {
974 _gens[i]->oop_iterate(mr, cl);
975 }
976 }
977
978 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
979 for (int i = 0; i < _n_gens; i++) {
980 _gens[i]->object_iterate(cl);
981 }
982 perm_gen()->object_iterate(cl);
983 }
984
985 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
986 for (int i = 0; i < _n_gens; i++) {
987 _gens[i]->safe_object_iterate(cl);
988 }
989 perm_gen()->safe_object_iterate(cl);
990 }
991
992 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
993 for (int i = 0; i < _n_gens; i++) {
994 _gens[i]->object_iterate_since_last_GC(cl);
995 }
996 }
997
998 Space* GenCollectedHeap::space_containing(const void* addr) const {
999 for (int i = 0; i < _n_gens; i++) {
1000 Space* res = _gens[i]->space_containing(addr);
1001 if (res != NULL) return res;
1002 }
1003 Space* res = perm_gen()->space_containing(addr);
1004 if (res != NULL) return res;
1005 // Otherwise...
1006 assert(false, "Could not find containing space");
1007 return NULL;
1008 }
1009
1010
1011 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1012 assert(is_in_reserved(addr), "block_start of address outside of heap");
1013 for (int i = 0; i < _n_gens; i++) {
1014 if (_gens[i]->is_in_reserved(addr)) {
1015 assert(_gens[i]->is_in(addr),
1016 "addr should be in allocated part of generation");
1017 return _gens[i]->block_start(addr);
1018 }
1019 }
1020 if (perm_gen()->is_in_reserved(addr)) {
1021 assert(perm_gen()->is_in(addr),
1022 "addr should be in allocated part of perm gen");
1023 return perm_gen()->block_start(addr);
1024 }
1025 assert(false, "Some generation should contain the address");
1026 return NULL;
1027 }
1028
1029 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1030 assert(is_in_reserved(addr), "block_size of address outside of heap");
1031 for (int i = 0; i < _n_gens; i++) {
1032 if (_gens[i]->is_in_reserved(addr)) {
1033 assert(_gens[i]->is_in(addr),
1034 "addr should be in allocated part of generation");
1035 return _gens[i]->block_size(addr);
1036 }
1037 }
1038 if (perm_gen()->is_in_reserved(addr)) {
1039 assert(perm_gen()->is_in(addr),
1040 "addr should be in allocated part of perm gen");
1041 return perm_gen()->block_size(addr);
1042 }
1043 assert(false, "Some generation should contain the address");
1044 return 0;
1045 }
1046
1047 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1048 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1049 assert(block_start(addr) == addr, "addr must be a block start");
1050 for (int i = 0; i < _n_gens; i++) {
1051 if (_gens[i]->is_in_reserved(addr)) {
1052 return _gens[i]->block_is_obj(addr);
1053 }
1054 }
1055 if (perm_gen()->is_in_reserved(addr)) {
1056 return perm_gen()->block_is_obj(addr);
1057 }
1058 assert(false, "Some generation should contain the address");
1059 return false;
1060 }
1061
1062 bool GenCollectedHeap::supports_tlab_allocation() const {
1063 for (int i = 0; i < _n_gens; i += 1) {
1064 if (_gens[i]->supports_tlab_allocation()) {
1065 return true;
1066 }
1067 }
1068 return false;
1069 }
1070
1071 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1072 size_t result = 0;
1073 for (int i = 0; i < _n_gens; i += 1) {
1074 if (_gens[i]->supports_tlab_allocation()) {
1075 result += _gens[i]->tlab_capacity();
1076 }
1077 }
1078 return result;
1079 }
1080
1081 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1082 size_t result = 0;
1083 for (int i = 0; i < _n_gens; i += 1) {
1084 if (_gens[i]->supports_tlab_allocation()) {
1085 result += _gens[i]->unsafe_max_tlab_alloc();
1086 }
1087 }
1088 return result;
1089 }
1090
1091 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1092 bool gc_overhead_limit_was_exceeded;
1093 return collector_policy()->mem_allocate_work(size /* size */,
1094 true /* is_tlab */,
1095 &gc_overhead_limit_was_exceeded);
1096 }
1097
1098 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1099 // from the list headed by "*prev_ptr".
1100 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1101 bool first = true;
1102 size_t min_size = 0; // "first" makes this conceptually infinite.
1103 ScratchBlock **smallest_ptr, *smallest;
1104 ScratchBlock *cur = *prev_ptr;
1105 while (cur) {
1106 assert(*prev_ptr == cur, "just checking");
1107 if (first || cur->num_words < min_size) {
1108 smallest_ptr = prev_ptr;
1109 smallest = cur;
1110 min_size = smallest->num_words;
1111 first = false;
1112 }
1113 prev_ptr = &cur->next;
1114 cur = cur->next;
1115 }
1116 smallest = *smallest_ptr;
1117 *smallest_ptr = smallest->next;
1118 return smallest;
1119 }
1120
1121 // Sort the scratch block list headed by res into decreasing size order,
1122 // and set "res" to the result.
1123 static void sort_scratch_list(ScratchBlock*& list) {
1124 ScratchBlock* sorted = NULL;
1125 ScratchBlock* unsorted = list;
1126 while (unsorted) {
1127 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1128 smallest->next = sorted;
1129 sorted = smallest;
1130 }
1131 list = sorted;
1132 }
1133
1134 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1135 size_t max_alloc_words) {
1136 ScratchBlock* res = NULL;
1137 for (int i = 0; i < _n_gens; i++) {
1138 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1139 }
1140 sort_scratch_list(res);
1141 return res;
1142 }
1143
1144 void GenCollectedHeap::release_scratch() {
1145 for (int i = 0; i < _n_gens; i++) {
1146 _gens[i]->reset_scratch();
1147 }
1148 }
1149
1150 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1151 void do_generation(Generation* gen) {
1152 gen->prepare_for_verify();
1153 }
1154 };
1155
1156 void GenCollectedHeap::prepare_for_verify() {
1157 ensure_parsability(false); // no need to retire TLABs
1158 GenPrepareForVerifyClosure blk;
1159 generation_iterate(&blk, false);
1160 perm_gen()->prepare_for_verify();
1161 }
1162
1163
1164 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1165 bool old_to_young) {
1166 if (old_to_young) {
1167 for (int i = _n_gens-1; i >= 0; i--) {
1168 cl->do_generation(_gens[i]);
1169 }
1170 } else {
1171 for (int i = 0; i < _n_gens; i++) {
1172 cl->do_generation(_gens[i]);
1173 }
1174 }
1175 }
1176
1177 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1178 for (int i = 0; i < _n_gens; i++) {
1179 _gens[i]->space_iterate(cl, true);
1180 }
1181 perm_gen()->space_iterate(cl, true);
1182 }
1183
1184 bool GenCollectedHeap::is_maximal_no_gc() const {
1185 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1186 if (!_gens[i]->is_maximal_no_gc()) {
1187 return false;
1188 }
1189 }
1190 return true;
1191 }
1192
1193 void GenCollectedHeap::save_marks() {
1194 for (int i = 0; i < _n_gens; i++) {
1195 _gens[i]->save_marks();
1196 }
1197 perm_gen()->save_marks();
1198 }
1199
1200 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1201 for (int i = 0; i <= collectedGen; i++) {
1202 _gens[i]->compute_new_size();
1203 }
1204 }
1205
1206 GenCollectedHeap* GenCollectedHeap::heap() {
1207 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1208 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1209 return _gch;
1210 }
1211
1212
1213 void GenCollectedHeap::prepare_for_compaction() {
1214 Generation* scanning_gen = _gens[_n_gens-1];
1215 // Start by compacting into same gen.
1216 CompactPoint cp(scanning_gen, NULL, NULL);
1217 while (scanning_gen != NULL) {
1218 scanning_gen->prepare_for_compaction(&cp);
1219 scanning_gen = prev_gen(scanning_gen);
1220 }
1221 }
1222
1223 GCStats* GenCollectedHeap::gc_stats(int level) const {
1224 return _gens[level]->gc_stats();
1225 }
1226
1227 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1228 if (!silent) {
1229 gclog_or_tty->print("permgen ");
1230 }
1231 perm_gen()->verify();
1232 for (int i = _n_gens-1; i >= 0; i--) {
1233 Generation* g = _gens[i];
1234 if (!silent) {
1235 gclog_or_tty->print(g->name());
1236 gclog_or_tty->print(" ");
1237 }
1238 g->verify();
1239 }
1240 if (!silent) {
1241 gclog_or_tty->print("remset ");
1242 }
1243 rem_set()->verify();
1244 }
1245
1246 void GenCollectedHeap::print_on(outputStream* st) const {
1247 for (int i = 0; i < _n_gens; i++) {
1248 _gens[i]->print_on(st);
1249 }
1250 perm_gen()->print_on(st);
1251 }
1252
1253 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1254 if (workers() != NULL) {
1255 workers()->threads_do(tc);
1256 }
1257 #ifndef SERIALGC
1258 if (UseConcMarkSweepGC) {
1259 ConcurrentMarkSweepThread::threads_do(tc);
1260 }
1261 #endif // SERIALGC
1262 }
1263
1264 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1265 #ifndef SERIALGC
1266 if (UseParNewGC) {
1267 workers()->print_worker_threads_on(st);
1268 }
1269 if (UseConcMarkSweepGC) {
1270 ConcurrentMarkSweepThread::print_all_on(st);
1271 }
1272 #endif // SERIALGC
1273 }
1274
1275 void GenCollectedHeap::print_tracing_info() const {
1276 if (TraceGen0Time) {
1277 get_gen(0)->print_summary_info();
1278 }
1279 if (TraceGen1Time) {
1280 get_gen(1)->print_summary_info();
1281 }
1282 }
1283
1284 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1285 if (PrintGCDetails && Verbose) {
1286 gclog_or_tty->print(" " SIZE_FORMAT
1287 "->" SIZE_FORMAT
1288 "(" SIZE_FORMAT ")",
1289 prev_used, used(), capacity());
1290 } else {
1291 gclog_or_tty->print(" " SIZE_FORMAT "K"
1292 "->" SIZE_FORMAT "K"
1293 "(" SIZE_FORMAT "K)",
1294 prev_used / K, used() / K, capacity() / K);
1295 }
1296 }
1297
1298 //New method to print perm gen info with PrintGCDetails flag
1299 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1300 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1301 perm_gen()->print_heap_change(perm_prev_used);
1302 gclog_or_tty->print("]");
1303 }
1304
1305 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1306 private:
1307 bool _full;
1308 public:
1309 void do_generation(Generation* gen) {
1310 gen->gc_prologue(_full);
1311 }
1312 GenGCPrologueClosure(bool full) : _full(full) {};
1313 };
1314
1315 void GenCollectedHeap::gc_prologue(bool full) {
1316 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1317
1318 always_do_update_barrier = false;
1319 // Fill TLAB's and such
1320 CollectedHeap::accumulate_statistics_all_tlabs();
1321 ensure_parsability(true); // retire TLABs
1322
1323 // Call allocation profiler
1324 AllocationProfiler::iterate_since_last_gc();
1325 // Walk generations
1326 GenGCPrologueClosure blk(full);
1327 generation_iterate(&blk, false); // not old-to-young.
1328 perm_gen()->gc_prologue(full);
1329 };
1330
1331 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1332 private:
1333 bool _full;
1334 public:
1335 void do_generation(Generation* gen) {
1336 gen->gc_epilogue(_full);
1337 }
1338 GenGCEpilogueClosure(bool full) : _full(full) {};
1339 };
1340
1341 void GenCollectedHeap::gc_epilogue(bool full) {
1342 #ifdef COMPILER2
1343 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1344 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1345 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1346 #endif /* COMPILER2 */
1347
1348 resize_all_tlabs();
1349
1350 GenGCEpilogueClosure blk(full);
1351 generation_iterate(&blk, false); // not old-to-young.
1352 perm_gen()->gc_epilogue(full);
1353
1354 if (!CleanChunkPoolAsync) {
1355 Chunk::clean_chunk_pool();
1356 }
1357
1358 always_do_update_barrier = UseConcMarkSweepGC;
1359 };
1360
1361 #ifndef PRODUCT
1362 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1363 private:
1364 public:
1365 void do_generation(Generation* gen) {
1366 gen->record_spaces_top();
1367 }
1368 };
1369
1370 void GenCollectedHeap::record_gen_tops_before_GC() {
1371 if (ZapUnusedHeapArea) {
1372 GenGCSaveTopsBeforeGCClosure blk;
1373 generation_iterate(&blk, false); // not old-to-young.
1374 perm_gen()->record_spaces_top();
1375 }
1376 }
1377 #endif // not PRODUCT
1378
1379 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1380 public:
1381 void do_generation(Generation* gen) {
1382 gen->ensure_parsability();
1383 }
1384 };
1385
1386 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1387 CollectedHeap::ensure_parsability(retire_tlabs);
1388 GenEnsureParsabilityClosure ep_cl;
1389 generation_iterate(&ep_cl, false);
1390 perm_gen()->ensure_parsability();
1391 }
1392
1393 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1394 oop obj,
1395 size_t obj_size) {
1396 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1397 HeapWord* result = NULL;
1398
1399 // First give each higher generation a chance to allocate the promoted object.
1400 Generation* allocator = next_gen(gen);
1401 if (allocator != NULL) {
1402 do {
1403 result = allocator->allocate(obj_size, false);
1404 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1405 }
1406
1407 if (result == NULL) {
1408 // Then give gen and higher generations a chance to expand and allocate the
1409 // object.
1410 do {
1411 result = gen->expand_and_allocate(obj_size, false);
1412 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1413 }
1414
1415 if (result != NULL) {
1416 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1417 }
1418 return oop(result);
1419 }
1420
1421 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1422 jlong _time; // in ms
1423 jlong _now; // in ms
1424
1425 public:
1426 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1427
1428 jlong time() { return _time; }
1429
1430 void do_generation(Generation* gen) {
1431 _time = MIN2(_time, gen->time_of_last_gc(_now));
1432 }
1433 };
1434
1435 jlong GenCollectedHeap::millis_since_last_gc() {
1436 // We need a monotonically non-deccreasing time in ms but
1437 // os::javaTimeMillis() does not guarantee monotonicity.
1438 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1439 GenTimeOfLastGCClosure tolgc_cl(now);
1440 // iterate over generations getting the oldest
1441 // time that a generation was collected
1442 generation_iterate(&tolgc_cl, false);
1443 tolgc_cl.do_generation(perm_gen());
1444
1445 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1446 // provided the underlying platform provides such a time source
1447 // (and it is bug free). So we still have to guard against getting
1448 // back a time later than 'now'.
1449 jlong retVal = now - tolgc_cl.time();
1450 if (retVal < 0) {
1451 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);)
1452 return 0;
1453 }
1454 return retVal;
1455 }