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 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
205 "the maximum representable size";
206
207 // Now figure out the total size.
208 size_t total_reserved = 0;
209 int n_covered_regions = 0;
210 const size_t pageSize = UseLargePages ?
211 os::large_page_size() : os::vm_page_size();
212
213 for (int i = 0; i < _n_gens; i++) {
214 total_reserved += _gen_specs[i]->max_size();
215 if (total_reserved < _gen_specs[i]->max_size()) {
216 vm_exit_during_initialization(overflow_msg);
217 }
218 n_covered_regions += _gen_specs[i]->n_covered_regions();
219 }
220 assert(total_reserved % pageSize == 0,
221 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
222 SIZE_FORMAT, total_reserved, pageSize));
223 total_reserved += perm_gen_spec->max_size();
224 assert(total_reserved % pageSize == 0,
225 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize="
226 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved,
227 pageSize, perm_gen_spec->max_size()));
228
229 if (total_reserved < perm_gen_spec->max_size()) {
230 vm_exit_during_initialization(overflow_msg);
231 }
232 n_covered_regions += perm_gen_spec->n_covered_regions();
233
234 // Add the size of the data area which shares the same reserved area
235 // as the heap, but which is not actually part of the heap.
236 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
237
238 total_reserved += s;
239 if (total_reserved < s) {
240 vm_exit_during_initialization(overflow_msg);
241 }
242
243 if (UseLargePages) {
244 assert(total_reserved != 0, "total_reserved cannot be 0");
245 total_reserved = round_to(total_reserved, os::large_page_size());
246 if (total_reserved < os::large_page_size()) {
247 vm_exit_during_initialization(overflow_msg);
248 }
249 }
250
251 // Calculate the address at which the heap must reside in order for
252 // the shared data to be at the required address.
253
254 char* heap_address;
255 if (UseSharedSpaces) {
256
257 // Calculate the address of the first word beyond the heap.
258 FileMapInfo* mapinfo = FileMapInfo::current_info();
259 int lr = CompactingPermGenGen::n_regions - 1;
260 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
261 heap_address = mapinfo->region_base(lr) + capacity;
262
263 // Calculate the address of the first word of the heap.
264 heap_address -= total_reserved;
265 } else {
266 heap_address = NULL; // any address will do.
267 if (UseCompressedOops) {
268 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
269 *_total_reserved = total_reserved;
270 *_n_covered_regions = n_covered_regions;
271 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
272 UseLargePages, heap_address);
273
274 if (heap_address != NULL && !heap_rs->is_reserved()) {
275 // Failed to reserve at specified address - the requested memory
276 // region is taken already, for example, by 'java' launcher.
277 // Try again to reserver heap higher.
278 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
279 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
280 UseLargePages, heap_address);
281
282 if (heap_address != NULL && !heap_rs->is_reserved()) {
283 // Failed to reserve at specified address again - give up.
284 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
285 assert(heap_address == NULL, "");
286 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
287 UseLargePages, heap_address);
288 }
289 }
290 return heap_address;
291 }
292 }
293
294 *_total_reserved = total_reserved;
295 *_n_covered_regions = n_covered_regions;
296 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
297 UseLargePages, heap_address);
298
299 return heap_address;
300 }
301
302
303 void GenCollectedHeap::post_initialize() {
304 SharedHeap::post_initialize();
305 TwoGenerationCollectorPolicy *policy =
306 (TwoGenerationCollectorPolicy *)collector_policy();
307 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
308 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
309 assert(def_new_gen->kind() == Generation::DefNew ||
310 def_new_gen->kind() == Generation::ParNew ||
311 def_new_gen->kind() == Generation::ASParNew,
312 "Wrong generation kind");
313
314 Generation* old_gen = get_gen(1);
315 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
316 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
317 old_gen->kind() == Generation::MarkSweepCompact,
318 "Wrong generation kind");
319
320 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
321 old_gen->capacity(),
322 def_new_gen->from()->capacity());
323 policy->initialize_gc_policy_counters();
324 }
325
326 void GenCollectedHeap::ref_processing_init() {
327 SharedHeap::ref_processing_init();
328 for (int i = 0; i < _n_gens; i++) {
329 _gens[i]->ref_processor_init();
330 }
331 }
332
333 size_t GenCollectedHeap::capacity() const {
334 size_t res = 0;
335 for (int i = 0; i < _n_gens; i++) {
336 res += _gens[i]->capacity();
337 }
338 return res;
339 }
340
341 size_t GenCollectedHeap::used() const {
342 size_t res = 0;
343 for (int i = 0; i < _n_gens; i++) {
344 res += _gens[i]->used();
345 }
346 return res;
347 }
348
349 // Save the "used_region" for generations level and lower,
350 // and, if perm is true, for perm gen.
351 void GenCollectedHeap::save_used_regions(int level, bool perm) {
352 assert(level < _n_gens, "Illegal level parameter");
353 for (int i = level; i >= 0; i--) {
354 _gens[i]->save_used_region();
355 }
356 if (perm) {
357 perm_gen()->save_used_region();
358 }
359 }
360
361 size_t GenCollectedHeap::max_capacity() const {
362 size_t res = 0;
363 for (int i = 0; i < _n_gens; i++) {
364 res += _gens[i]->max_capacity();
365 }
366 return res;
367 }
368
369 // Update the _full_collections_completed counter
370 // at the end of a stop-world full GC.
371 unsigned int GenCollectedHeap::update_full_collections_completed() {
372 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
373 assert(_full_collections_completed <= _total_full_collections,
374 "Can't complete more collections than were started");
375 _full_collections_completed = _total_full_collections;
376 ml.notify_all();
377 return _full_collections_completed;
378 }
379
380 // Update the _full_collections_completed counter, as appropriate,
381 // at the end of a concurrent GC cycle. Note the conditional update
382 // below to allow this method to be called by a concurrent collector
383 // without synchronizing in any manner with the VM thread (which
384 // may already have initiated a STW full collection "concurrently").
385 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
386 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
387 assert((_full_collections_completed <= _total_full_collections) &&
388 (count <= _total_full_collections),
389 "Can't complete more collections than were started");
390 if (count > _full_collections_completed) {
391 _full_collections_completed = count;
392 ml.notify_all();
393 }
394 return _full_collections_completed;
395 }
396
397
398 #ifndef PRODUCT
399 // Override of memory state checking method in CollectedHeap:
400 // Some collectors (CMS for example) can't have badHeapWordVal written
401 // in the first two words of an object. (For instance , in the case of
402 // CMS these words hold state used to synchronize between certain
403 // (concurrent) GC steps and direct allocating mutators.)
404 // The skip_header_HeapWords() method below, allows us to skip
405 // over the requisite number of HeapWord's. Note that (for
406 // generational collectors) this means that those many words are
407 // skipped in each object, irrespective of the generation in which
408 // that object lives. The resultant loss of precision seems to be
409 // harmless and the pain of avoiding that imprecision appears somewhat
410 // higher than we are prepared to pay for such rudimentary debugging
411 // support.
412 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
413 size_t size) {
414 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
415 // We are asked to check a size in HeapWords,
416 // but the memory is mangled in juint words.
417 juint* start = (juint*) (addr + skip_header_HeapWords());
418 juint* end = (juint*) (addr + size);
419 for (juint* slot = start; slot < end; slot += 1) {
420 assert(*slot == badHeapWordVal,
421 "Found non badHeapWordValue in pre-allocation check");
422 }
423 }
424 }
425 #endif
426
427 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
428 bool is_tlab,
429 bool first_only) {
430 HeapWord* res;
431 for (int i = 0; i < _n_gens; i++) {
432 if (_gens[i]->should_allocate(size, is_tlab)) {
433 res = _gens[i]->allocate(size, is_tlab);
434 if (res != NULL) return res;
435 else if (first_only) break;
436 }
437 }
438 // Otherwise...
439 return NULL;
440 }
441
442 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
443 bool* gc_overhead_limit_was_exceeded) {
444 return collector_policy()->mem_allocate_work(size,
445 false /* is_tlab */,
446 gc_overhead_limit_was_exceeded);
447 }
448
449 bool GenCollectedHeap::must_clear_all_soft_refs() {
450 return _gc_cause == GCCause::_last_ditch_collection;
451 }
452
453 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
454 return UseConcMarkSweepGC &&
455 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
456 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
457 }
458
459 void GenCollectedHeap::do_collection(bool full,
460 bool clear_all_soft_refs,
461 size_t size,
462 bool is_tlab,
463 int max_level) {
464 bool prepared_for_verification = false;
465 ResourceMark rm;
466 DEBUG_ONLY(Thread* my_thread = Thread::current();)
467
468 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
469 assert(my_thread->is_VM_thread() ||
470 my_thread->is_ConcurrentGC_thread(),
471 "incorrect thread type capability");
472 assert(Heap_lock->is_locked(),
473 "the requesting thread should have the Heap_lock");
474 guarantee(!is_gc_active(), "collection is not reentrant");
475 assert(max_level < n_gens(), "sanity check");
476
477 if (GC_locker::check_active_before_gc()) {
478 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
479 }
480
481 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
482 collector_policy()->should_clear_all_soft_refs();
483
484 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
485
486 const size_t perm_prev_used = perm_gen()->used();
487
488 print_heap_before_gc();
489
490 {
491 FlagSetting fl(_is_gc_active, true);
492
493 bool complete = full && (max_level == (n_gens()-1));
494 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
495 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
496 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
497 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL);
498
499 gc_prologue(complete);
500 increment_total_collections(complete);
501
502 size_t gch_prev_used = used();
503
504 int starting_level = 0;
505 if (full) {
506 // Search for the oldest generation which will collect all younger
507 // generations, and start collection loop there.
508 for (int i = max_level; i >= 0; i--) {
509 if (_gens[i]->full_collects_younger_generations()) {
510 starting_level = i;
511 break;
512 }
513 }
514 }
515
516 bool must_restore_marks_for_biased_locking = false;
517
518 int max_level_collected = starting_level;
519 for (int i = starting_level; i <= max_level; i++) {
520 if (_gens[i]->should_collect(full, size, is_tlab)) {
521 if (i == n_gens() - 1) { // a major collection is to happen
522 if (!complete) {
523 // The full_collections increment was missed above.
524 increment_total_full_collections();
525 }
526 pre_full_gc_dump(NULL); // do any pre full gc dumps
527 }
528 // Timer for individual generations. Last argument is false: no CR
529 // FIXME: We should try to start the timing earlier to cover more of the GC pause
530 GCTraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, NULL);
531 TraceCollectorStats tcs(_gens[i]->counters());
532 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
533
534 size_t prev_used = _gens[i]->used();
535 _gens[i]->stat_record()->invocations++;
536 _gens[i]->stat_record()->accumulated_time.start();
537
538 // Must be done anew before each collection because
539 // a previous collection will do mangling and will
540 // change top of some spaces.
541 record_gen_tops_before_GC();
542
543 if (PrintGC && Verbose) {
544 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
545 i,
546 _gens[i]->stat_record()->invocations,
547 size*HeapWordSize);
548 }
549
550 if (VerifyBeforeGC && i >= VerifyGCLevel &&
551 total_collections() >= VerifyGCStartAt) {
552 HandleMark hm; // Discard invalid handles created during verification
553 if (!prepared_for_verification) {
554 prepare_for_verify();
555 prepared_for_verification = true;
556 }
557 gclog_or_tty->print(" VerifyBeforeGC:");
558 Universe::verify();
559 }
560 COMPILER2_PRESENT(DerivedPointerTable::clear());
561
562 if (!must_restore_marks_for_biased_locking &&
563 _gens[i]->performs_in_place_marking()) {
564 // We perform this mark word preservation work lazily
565 // because it's only at this point that we know whether we
566 // absolutely have to do it; we want to avoid doing it for
567 // scavenge-only collections where it's unnecessary
568 must_restore_marks_for_biased_locking = true;
569 BiasedLocking::preserve_marks();
570 }
571
572 // Do collection work
573 {
574 // Note on ref discovery: For what appear to be historical reasons,
575 // GCH enables and disabled (by enqueing) refs discovery.
576 // In the future this should be moved into the generation's
577 // collect method so that ref discovery and enqueueing concerns
578 // are local to a generation. The collect method could return
579 // an appropriate indication in the case that notification on
580 // the ref lock was needed. This will make the treatment of
581 // weak refs more uniform (and indeed remove such concerns
582 // from GCH). XXX
583
584 HandleMark hm; // Discard invalid handles created during gc
585 save_marks(); // save marks for all gens
586 // We want to discover references, but not process them yet.
587 // This mode is disabled in process_discovered_references if the
588 // generation does some collection work, or in
589 // enqueue_discovered_references if the generation returns
590 // without doing any work.
591 ReferenceProcessor* rp = _gens[i]->ref_processor();
592 // If the discovery of ("weak") refs in this generation is
593 // atomic wrt other collectors in this configuration, we
594 // are guaranteed to have empty discovered ref lists.
595 if (rp->discovery_is_atomic()) {
596 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
597 rp->setup_policy(do_clear_all_soft_refs);
598 } else {
599 // collect() below will enable discovery as appropriate
600 }
601 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
602 if (!rp->enqueuing_is_done()) {
603 rp->enqueue_discovered_references();
604 } else {
605 rp->set_enqueuing_is_done(false);
606 }
607 rp->verify_no_references_recorded();
608 }
609 max_level_collected = i;
610
611 // Determine if allocation request was met.
612 if (size > 0) {
613 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
614 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
615 size = 0;
616 }
617 }
618 }
619
620 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
621
622 _gens[i]->stat_record()->accumulated_time.stop();
623
624 update_gc_stats(i, full);
625
626 if (VerifyAfterGC && i >= VerifyGCLevel &&
627 total_collections() >= VerifyGCStartAt) {
628 HandleMark hm; // Discard invalid handles created during verification
629 gclog_or_tty->print(" VerifyAfterGC:");
630 Universe::verify();
631 }
632
633 if (PrintGCDetails) {
634 gclog_or_tty->print(":");
635 _gens[i]->print_heap_change(prev_used);
636 }
637 }
638 }
639
640 // Update "complete" boolean wrt what actually transpired --
641 // for instance, a promotion failure could have led to
642 // a whole heap collection.
643 complete = complete || (max_level_collected == n_gens() - 1);
644
645 if (complete) { // We did a "major" collection
646 // FIXME: See comment at pre_full_gc_dump call
647 post_full_gc_dump(NULL); // do any post full gc dumps
648 }
649
650 if (PrintGCDetails) {
651 print_heap_change(gch_prev_used);
652
653 // Print perm gen info for full GC with PrintGCDetails flag.
654 if (complete) {
655 print_perm_heap_change(perm_prev_used);
656 }
657 }
658
659 for (int j = max_level_collected; j >= 0; j -= 1) {
660 // Adjust generation sizes.
661 _gens[j]->compute_new_size();
662 }
663
664 if (complete) {
665 // Ask the permanent generation to adjust size for full collections
666 perm()->compute_new_size();
667 update_full_collections_completed();
668 }
669
670 // Track memory usage and detect low memory after GC finishes
671 MemoryService::track_memory_usage();
672
673 gc_epilogue(complete);
674
675 if (must_restore_marks_for_biased_locking) {
676 BiasedLocking::restore_marks();
677 }
678 }
679
680 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
681 AdaptiveSizePolicyOutput(sp, total_collections());
682
683 print_heap_after_gc();
684
685 #ifdef TRACESPINNING
686 ParallelTaskTerminator::print_termination_counts();
687 #endif
688 }
689
690 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
691 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
692 }
693
694 void GenCollectedHeap::set_par_threads(uint t) {
695 SharedHeap::set_par_threads(t);
696 _gen_process_strong_tasks->set_n_threads(t);
697 }
698
699 void GenCollectedHeap::
700 gen_process_strong_roots(int level,
701 bool younger_gens_as_roots,
702 bool activate_scope,
703 bool collecting_perm_gen,
704 SharedHeap::ScanningOption so,
705 OopsInGenClosure* not_older_gens,
706 bool do_code_roots,
707 OopsInGenClosure* older_gens) {
708 // General strong roots.
709
710 if (!do_code_roots) {
711 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
712 not_older_gens, NULL, older_gens);
713 } else {
714 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
715 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
716 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
717 not_older_gens, &code_roots, older_gens);
718 }
719
720 if (younger_gens_as_roots) {
721 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
722 for (int i = 0; i < level; i++) {
723 not_older_gens->set_generation(_gens[i]);
724 _gens[i]->oop_iterate(not_older_gens);
725 }
726 not_older_gens->reset_generation();
727 }
728 }
729 // When collection is parallel, all threads get to cooperate to do
730 // older-gen scanning.
731 for (int i = level+1; i < _n_gens; i++) {
732 older_gens->set_generation(_gens[i]);
733 rem_set()->younger_refs_iterate(_gens[i], older_gens);
734 older_gens->reset_generation();
735 }
736
737 _gen_process_strong_tasks->all_tasks_completed();
738 }
739
740 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
741 CodeBlobClosure* code_roots,
742 OopClosure* non_root_closure) {
743 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
744 // "Local" "weak" refs
745 for (int i = 0; i < _n_gens; i++) {
746 _gens[i]->ref_processor()->weak_oops_do(root_closure);
747 }
748 }
749
750 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
751 void GenCollectedHeap:: \
752 oop_since_save_marks_iterate(int level, \
753 OopClosureType* cur, \
754 OopClosureType* older) { \
755 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
756 for (int i = level+1; i < n_gens(); i++) { \
757 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
758 } \
759 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
760 }
761
762 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
763
764 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
765
766 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
767 for (int i = level; i < _n_gens; i++) {
768 if (!_gens[i]->no_allocs_since_save_marks()) return false;
769 }
770 return perm_gen()->no_allocs_since_save_marks();
771 }
772
773 bool GenCollectedHeap::supports_inline_contig_alloc() const {
774 return _gens[0]->supports_inline_contig_alloc();
775 }
776
777 HeapWord** GenCollectedHeap::top_addr() const {
778 return _gens[0]->top_addr();
779 }
780
781 HeapWord** GenCollectedHeap::end_addr() const {
782 return _gens[0]->end_addr();
783 }
784
785 size_t GenCollectedHeap::unsafe_max_alloc() {
786 return _gens[0]->unsafe_max_alloc_nogc();
787 }
788
789 // public collection interfaces
790
791 void GenCollectedHeap::collect(GCCause::Cause cause) {
792 if (should_do_concurrent_full_gc(cause)) {
793 #ifndef SERIALGC
794 // mostly concurrent full collection
795 collect_mostly_concurrent(cause);
796 #else // SERIALGC
797 ShouldNotReachHere();
798 #endif // SERIALGC
799 } else {
800 #ifdef ASSERT
801 if (cause == GCCause::_scavenge_alot) {
802 // minor collection only
803 collect(cause, 0);
804 } else {
805 // Stop-the-world full collection
806 collect(cause, n_gens() - 1);
807 }
808 #else
809 // Stop-the-world full collection
810 collect(cause, n_gens() - 1);
811 #endif
812 }
813 }
814
815 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
816 // The caller doesn't have the Heap_lock
817 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
818 MutexLocker ml(Heap_lock);
819 collect_locked(cause, max_level);
820 }
821
822 // This interface assumes that it's being called by the
823 // vm thread. It collects the heap assuming that the
824 // heap lock is already held and that we are executing in
825 // the context of the vm thread.
826 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
827 assert(Thread::current()->is_VM_thread(), "Precondition#1");
828 assert(Heap_lock->is_locked(), "Precondition#2");
829 GCCauseSetter gcs(this, cause);
830 switch (cause) {
831 case GCCause::_heap_inspection:
832 case GCCause::_heap_dump: {
833 HandleMark hm;
834 do_full_collection(false, // don't clear all soft refs
835 n_gens() - 1);
836 break;
837 }
838 default: // XXX FIX ME
839 ShouldNotReachHere(); // Unexpected use of this function
840 }
841 }
842
843 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
844 // The caller has the Heap_lock
845 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
846 collect_locked(cause, n_gens() - 1);
847 }
848
849 // this is the private collection interface
850 // The Heap_lock is expected to be held on entry.
851
852 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
853 if (_preloading_shared_classes) {
854 report_out_of_shared_space(SharedPermGen);
855 }
856 // Read the GC count while holding the Heap_lock
857 unsigned int gc_count_before = total_collections();
858 unsigned int full_gc_count_before = total_full_collections();
859 {
860 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
861 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
862 cause, max_level);
863 VMThread::execute(&op);
864 }
865 }
866
867 #ifndef SERIALGC
868 bool GenCollectedHeap::create_cms_collector() {
869
870 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
871 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
872 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
873 "Unexpected generation kinds");
874 // Skip two header words in the block content verification
875 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
876 CMSCollector* collector = new CMSCollector(
877 (ConcurrentMarkSweepGeneration*)_gens[1],
878 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
879 _rem_set->as_CardTableRS(),
880 (ConcurrentMarkSweepPolicy*) collector_policy());
881
882 if (collector == NULL || !collector->completed_initialization()) {
883 if (collector) {
884 delete collector; // Be nice in embedded situation
885 }
886 vm_shutdown_during_initialization("Could not create CMS collector");
887 return false;
888 }
889 return true; // success
890 }
891
892 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
893 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
894
895 MutexLocker ml(Heap_lock);
896 // Read the GC counts while holding the Heap_lock
897 unsigned int full_gc_count_before = total_full_collections();
898 unsigned int gc_count_before = total_collections();
899 {
900 MutexUnlocker mu(Heap_lock);
901 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
902 VMThread::execute(&op);
903 }
904 }
905 #endif // SERIALGC
906
907
908 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
909 int max_level) {
910 int local_max_level;
911 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
912 gc_cause() == GCCause::_gc_locker) {
913 local_max_level = 0;
914 } else {
915 local_max_level = max_level;
916 }
917
918 do_collection(true /* full */,
919 clear_all_soft_refs /* clear_all_soft_refs */,
920 0 /* size */,
921 false /* is_tlab */,
922 local_max_level /* max_level */);
923 // Hack XXX FIX ME !!!
924 // A scavenge may not have been attempted, or may have
925 // been attempted and failed, because the old gen was too full
926 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
927 incremental_collection_will_fail(false /* don't consult_young */)) {
928 if (PrintGCDetails) {
929 gclog_or_tty->print_cr("GC locker: Trying a full collection "
930 "because scavenge failed");
931 }
932 // This time allow the old gen to be collected as well
933 do_collection(true /* full */,
934 clear_all_soft_refs /* clear_all_soft_refs */,
935 0 /* size */,
936 false /* is_tlab */,
937 n_gens() - 1 /* max_level */);
938 }
939 }
940
941 bool GenCollectedHeap::is_in_young(oop p) {
942 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
943 assert(result == _gens[0]->is_in_reserved(p),
944 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, (void*)p));
945 return result;
946 }
947
948 // Returns "TRUE" iff "p" points into the committed areas of the heap.
949 bool GenCollectedHeap::is_in(const void* p) const {
950 #ifndef ASSERT
951 guarantee(VerifyBeforeGC ||
952 VerifyDuringGC ||
953 VerifyBeforeExit ||
954 PrintAssembly ||
955 tty->count() != 0 || // already printing
956 VerifyAfterGC ||
957 VMError::fatal_error_in_progress(), "too expensive");
958
959 #endif
960 // This might be sped up with a cache of the last generation that
961 // answered yes.
962 for (int i = 0; i < _n_gens; i++) {
963 if (_gens[i]->is_in(p)) return true;
964 }
965 if (_perm_gen->as_gen()->is_in(p)) return true;
966 // Otherwise...
967 return false;
968 }
969
970 #ifdef ASSERT
971 // Don't implement this by using is_in_young(). This method is used
972 // in some cases to check that is_in_young() is correct.
973 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
974 assert(is_in_reserved(p) || p == NULL,
975 "Does not work if address is non-null and outside of the heap");
976 // The order of the generations is young (low addr), old, perm (high addr)
977 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
978 }
979 #endif
980
981 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
982 for (int i = 0; i < _n_gens; i++) {
983 _gens[i]->oop_iterate(cl);
984 }
985 }
986
987 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
988 for (int i = 0; i < _n_gens; i++) {
989 _gens[i]->oop_iterate(mr, cl);
990 }
991 }
992
993 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
994 for (int i = 0; i < _n_gens; i++) {
995 _gens[i]->object_iterate(cl);
996 }
997 perm_gen()->object_iterate(cl);
998 }
999
1000 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
1001 for (int i = 0; i < _n_gens; i++) {
1002 _gens[i]->safe_object_iterate(cl);
1003 }
1004 perm_gen()->safe_object_iterate(cl);
1005 }
1006
1007 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
1008 for (int i = 0; i < _n_gens; i++) {
1009 _gens[i]->object_iterate_since_last_GC(cl);
1010 }
1011 }
1012
1013 Space* GenCollectedHeap::space_containing(const void* addr) const {
1014 for (int i = 0; i < _n_gens; i++) {
1015 Space* res = _gens[i]->space_containing(addr);
1016 if (res != NULL) return res;
1017 }
1018 Space* res = perm_gen()->space_containing(addr);
1019 if (res != NULL) return res;
1020 // Otherwise...
1021 assert(false, "Could not find containing space");
1022 return NULL;
1023 }
1024
1025
1026 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1027 assert(is_in_reserved(addr), "block_start of address outside of heap");
1028 for (int i = 0; i < _n_gens; i++) {
1029 if (_gens[i]->is_in_reserved(addr)) {
1030 assert(_gens[i]->is_in(addr),
1031 "addr should be in allocated part of generation");
1032 return _gens[i]->block_start(addr);
1033 }
1034 }
1035 if (perm_gen()->is_in_reserved(addr)) {
1036 assert(perm_gen()->is_in(addr),
1037 "addr should be in allocated part of perm gen");
1038 return perm_gen()->block_start(addr);
1039 }
1040 assert(false, "Some generation should contain the address");
1041 return NULL;
1042 }
1043
1044 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1045 assert(is_in_reserved(addr), "block_size of address outside of heap");
1046 for (int i = 0; i < _n_gens; i++) {
1047 if (_gens[i]->is_in_reserved(addr)) {
1048 assert(_gens[i]->is_in(addr),
1049 "addr should be in allocated part of generation");
1050 return _gens[i]->block_size(addr);
1051 }
1052 }
1053 if (perm_gen()->is_in_reserved(addr)) {
1054 assert(perm_gen()->is_in(addr),
1055 "addr should be in allocated part of perm gen");
1056 return perm_gen()->block_size(addr);
1057 }
1058 assert(false, "Some generation should contain the address");
1059 return 0;
1060 }
1061
1062 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1063 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1064 assert(block_start(addr) == addr, "addr must be a block start");
1065 for (int i = 0; i < _n_gens; i++) {
1066 if (_gens[i]->is_in_reserved(addr)) {
1067 return _gens[i]->block_is_obj(addr);
1068 }
1069 }
1070 if (perm_gen()->is_in_reserved(addr)) {
1071 return perm_gen()->block_is_obj(addr);
1072 }
1073 assert(false, "Some generation should contain the address");
1074 return false;
1075 }
1076
1077 bool GenCollectedHeap::supports_tlab_allocation() const {
1078 for (int i = 0; i < _n_gens; i += 1) {
1079 if (_gens[i]->supports_tlab_allocation()) {
1080 return true;
1081 }
1082 }
1083 return false;
1084 }
1085
1086 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1087 size_t result = 0;
1088 for (int i = 0; i < _n_gens; i += 1) {
1089 if (_gens[i]->supports_tlab_allocation()) {
1090 result += _gens[i]->tlab_capacity();
1091 }
1092 }
1093 return result;
1094 }
1095
1096 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1097 size_t result = 0;
1098 for (int i = 0; i < _n_gens; i += 1) {
1099 if (_gens[i]->supports_tlab_allocation()) {
1100 result += _gens[i]->unsafe_max_tlab_alloc();
1101 }
1102 }
1103 return result;
1104 }
1105
1106 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1107 bool gc_overhead_limit_was_exceeded;
1108 return collector_policy()->mem_allocate_work(size /* size */,
1109 true /* is_tlab */,
1110 &gc_overhead_limit_was_exceeded);
1111 }
1112
1113 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1114 // from the list headed by "*prev_ptr".
1115 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1116 bool first = true;
1117 size_t min_size = 0; // "first" makes this conceptually infinite.
1118 ScratchBlock **smallest_ptr, *smallest;
1119 ScratchBlock *cur = *prev_ptr;
1120 while (cur) {
1121 assert(*prev_ptr == cur, "just checking");
1122 if (first || cur->num_words < min_size) {
1123 smallest_ptr = prev_ptr;
1124 smallest = cur;
1125 min_size = smallest->num_words;
1126 first = false;
1127 }
1128 prev_ptr = &cur->next;
1129 cur = cur->next;
1130 }
1131 smallest = *smallest_ptr;
1132 *smallest_ptr = smallest->next;
1133 return smallest;
1134 }
1135
1136 // Sort the scratch block list headed by res into decreasing size order,
1137 // and set "res" to the result.
1138 static void sort_scratch_list(ScratchBlock*& list) {
1139 ScratchBlock* sorted = NULL;
1140 ScratchBlock* unsorted = list;
1141 while (unsorted) {
1142 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1143 smallest->next = sorted;
1144 sorted = smallest;
1145 }
1146 list = sorted;
1147 }
1148
1149 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1150 size_t max_alloc_words) {
1151 ScratchBlock* res = NULL;
1152 for (int i = 0; i < _n_gens; i++) {
1153 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1154 }
1155 sort_scratch_list(res);
1156 return res;
1157 }
1158
1159 void GenCollectedHeap::release_scratch() {
1160 for (int i = 0; i < _n_gens; i++) {
1161 _gens[i]->reset_scratch();
1162 }
1163 }
1164
1165 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1166 void do_generation(Generation* gen) {
1167 gen->prepare_for_verify();
1168 }
1169 };
1170
1171 void GenCollectedHeap::prepare_for_verify() {
1172 ensure_parsability(false); // no need to retire TLABs
1173 GenPrepareForVerifyClosure blk;
1174 generation_iterate(&blk, false);
1175 perm_gen()->prepare_for_verify();
1176 }
1177
1178
1179 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1180 bool old_to_young) {
1181 if (old_to_young) {
1182 for (int i = _n_gens-1; i >= 0; i--) {
1183 cl->do_generation(_gens[i]);
1184 }
1185 } else {
1186 for (int i = 0; i < _n_gens; i++) {
1187 cl->do_generation(_gens[i]);
1188 }
1189 }
1190 }
1191
1192 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1193 for (int i = 0; i < _n_gens; i++) {
1194 _gens[i]->space_iterate(cl, true);
1195 }
1196 perm_gen()->space_iterate(cl, true);
1197 }
1198
1199 bool GenCollectedHeap::is_maximal_no_gc() const {
1200 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1201 if (!_gens[i]->is_maximal_no_gc()) {
1202 return false;
1203 }
1204 }
1205 return true;
1206 }
1207
1208 void GenCollectedHeap::save_marks() {
1209 for (int i = 0; i < _n_gens; i++) {
1210 _gens[i]->save_marks();
1211 }
1212 perm_gen()->save_marks();
1213 }
1214
1215 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1216 for (int i = 0; i <= collectedGen; i++) {
1217 _gens[i]->compute_new_size();
1218 }
1219 }
1220
1221 GenCollectedHeap* GenCollectedHeap::heap() {
1222 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1223 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1224 return _gch;
1225 }
1226
1227
1228 void GenCollectedHeap::prepare_for_compaction() {
1229 Generation* scanning_gen = _gens[_n_gens-1];
1230 // Start by compacting into same gen.
1231 CompactPoint cp(scanning_gen, NULL, NULL);
1232 while (scanning_gen != NULL) {
1233 scanning_gen->prepare_for_compaction(&cp);
1234 scanning_gen = prev_gen(scanning_gen);
1235 }
1236 }
1237
1238 GCStats* GenCollectedHeap::gc_stats(int level) const {
1239 return _gens[level]->gc_stats();
1240 }
1241
1242 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1243 if (!silent) {
1244 gclog_or_tty->print("permgen ");
1245 }
1246 perm_gen()->verify();
1247 for (int i = _n_gens-1; i >= 0; i--) {
1248 Generation* g = _gens[i];
1249 if (!silent) {
1250 gclog_or_tty->print(g->name());
1251 gclog_or_tty->print(" ");
1252 }
1253 g->verify();
1254 }
1255 if (!silent) {
1256 gclog_or_tty->print("remset ");
1257 }
1258 rem_set()->verify();
1259 }
1260
1261 void GenCollectedHeap::print_on(outputStream* st) const {
1262 for (int i = 0; i < _n_gens; i++) {
1263 _gens[i]->print_on(st);
1264 }
1265 perm_gen()->print_on(st);
1266 }
1267
1268 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1269 if (workers() != NULL) {
1270 workers()->threads_do(tc);
1271 }
1272 #ifndef SERIALGC
1273 if (UseConcMarkSweepGC) {
1274 ConcurrentMarkSweepThread::threads_do(tc);
1275 }
1276 #endif // SERIALGC
1277 }
1278
1279 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1280 #ifndef SERIALGC
1281 if (UseParNewGC) {
1282 workers()->print_worker_threads_on(st);
1283 }
1284 if (UseConcMarkSweepGC) {
1285 ConcurrentMarkSweepThread::print_all_on(st);
1286 }
1287 #endif // SERIALGC
1288 }
1289
1290 void GenCollectedHeap::print_tracing_info() const {
1291 if (TraceGen0Time) {
1292 get_gen(0)->print_summary_info();
1293 }
1294 if (TraceGen1Time) {
1295 get_gen(1)->print_summary_info();
1296 }
1297 }
1298
1299 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1300 if (PrintGCDetails && Verbose) {
1301 gclog_or_tty->print(" " SIZE_FORMAT
1302 "->" SIZE_FORMAT
1303 "(" SIZE_FORMAT ")",
1304 prev_used, used(), capacity());
1305 } else {
1306 gclog_or_tty->print(" " SIZE_FORMAT "K"
1307 "->" SIZE_FORMAT "K"
1308 "(" SIZE_FORMAT "K)",
1309 prev_used / K, used() / K, capacity() / K);
1310 }
1311 }
1312
1313 //New method to print perm gen info with PrintGCDetails flag
1314 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1315 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1316 perm_gen()->print_heap_change(perm_prev_used);
1317 gclog_or_tty->print("]");
1318 }
1319
1320 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1321 private:
1322 bool _full;
1323 public:
1324 void do_generation(Generation* gen) {
1325 gen->gc_prologue(_full);
1326 }
1327 GenGCPrologueClosure(bool full) : _full(full) {};
1328 };
1329
1330 void GenCollectedHeap::gc_prologue(bool full) {
1331 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1332
1333 always_do_update_barrier = false;
1334 // Fill TLAB's and such
1335 CollectedHeap::accumulate_statistics_all_tlabs();
1336 ensure_parsability(true); // retire TLABs
1337
1338 // Call allocation profiler
1339 AllocationProfiler::iterate_since_last_gc();
1340 // Walk generations
1341 GenGCPrologueClosure blk(full);
1342 generation_iterate(&blk, false); // not old-to-young.
1343 perm_gen()->gc_prologue(full);
1344 };
1345
1346 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1347 private:
1348 bool _full;
1349 public:
1350 void do_generation(Generation* gen) {
1351 gen->gc_epilogue(_full);
1352 }
1353 GenGCEpilogueClosure(bool full) : _full(full) {};
1354 };
1355
1356 void GenCollectedHeap::gc_epilogue(bool full) {
1357 #ifdef COMPILER2
1358 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1359 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1360 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1361 #endif /* COMPILER2 */
1362
1363 resize_all_tlabs();
1364
1365 GenGCEpilogueClosure blk(full);
1366 generation_iterate(&blk, false); // not old-to-young.
1367 perm_gen()->gc_epilogue(full);
1368
1369 if (!CleanChunkPoolAsync) {
1370 Chunk::clean_chunk_pool();
1371 }
1372
1373 always_do_update_barrier = UseConcMarkSweepGC;
1374 };
1375
1376 #ifndef PRODUCT
1377 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1378 private:
1379 public:
1380 void do_generation(Generation* gen) {
1381 gen->record_spaces_top();
1382 }
1383 };
1384
1385 void GenCollectedHeap::record_gen_tops_before_GC() {
1386 if (ZapUnusedHeapArea) {
1387 GenGCSaveTopsBeforeGCClosure blk;
1388 generation_iterate(&blk, false); // not old-to-young.
1389 perm_gen()->record_spaces_top();
1390 }
1391 }
1392 #endif // not PRODUCT
1393
1394 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1395 public:
1396 void do_generation(Generation* gen) {
1397 gen->ensure_parsability();
1398 }
1399 };
1400
1401 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1402 CollectedHeap::ensure_parsability(retire_tlabs);
1403 GenEnsureParsabilityClosure ep_cl;
1404 generation_iterate(&ep_cl, false);
1405 perm_gen()->ensure_parsability();
1406 }
1407
1408 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1409 oop obj,
1410 size_t obj_size) {
1411 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1412 HeapWord* result = NULL;
1413
1414 // First give each higher generation a chance to allocate the promoted object.
1415 Generation* allocator = next_gen(gen);
1416 if (allocator != NULL) {
1417 do {
1418 result = allocator->allocate(obj_size, false);
1419 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1420 }
1421
1422 if (result == NULL) {
1423 // Then give gen and higher generations a chance to expand and allocate the
1424 // object.
1425 do {
1426 result = gen->expand_and_allocate(obj_size, false);
1427 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1428 }
1429
1430 if (result != NULL) {
1431 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1432 }
1433 return oop(result);
1434 }
1435
1436 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1437 jlong _time; // in ms
1438 jlong _now; // in ms
1439
1440 public:
1441 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1442
1443 jlong time() { return _time; }
1444
1445 void do_generation(Generation* gen) {
1446 _time = MIN2(_time, gen->time_of_last_gc(_now));
1447 }
1448 };
1449
1450 jlong GenCollectedHeap::millis_since_last_gc() {
1451 // We need a monotonically non-deccreasing time in ms but
1452 // os::javaTimeMillis() does not guarantee monotonicity.
1453 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1454 GenTimeOfLastGCClosure tolgc_cl(now);
1455 // iterate over generations getting the oldest
1456 // time that a generation was collected
1457 generation_iterate(&tolgc_cl, false);
1458 tolgc_cl.do_generation(perm_gen());
1459
1460 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1461 // provided the underlying platform provides such a time source
1462 // (and it is bug free). So we still have to guard against getting
1463 // back a time later than 'now'.
1464 jlong retVal = now - tolgc_cl.time();
1465 if (retVal < 0) {
1466 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);)
1467 return 0;
1468 }
1469 return retVal;
1470 }