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/vmGCOperations.hpp"
32 #include "gc_interface/collectedHeap.inline.hpp"
33 #include "memory/compactPermGen.hpp"
34 #include "memory/filemap.hpp"
35 #include "memory/gcLocker.inline.hpp"
36 #include "memory/genCollectedHeap.hpp"
37 #include "memory/genOopClosures.inline.hpp"
38 #include "memory/generation.inline.hpp"
39 #include "memory/generationSpec.hpp"
40 #include "memory/permGen.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "memory/sharedHeap.hpp"
43 #include "memory/space.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "runtime/aprofiler.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/fprofiler.hpp"
49 #include "runtime/handles.hpp"
50 #include "runtime/handles.inline.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/vmThread.hpp"
53 #include "services/memoryService.hpp"
54 #include "utilities/vmError.hpp"
55 #include "utilities/workgroup.hpp"
56 #ifndef SERIALGC
57 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
58 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp"
59 #endif
60
61 GenCollectedHeap* GenCollectedHeap::_gch;
62 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
63
64 // The set of potentially parallel tasks in strong root scanning.
65 enum GCH_process_strong_roots_tasks {
66 // We probably want to parallelize both of these internally, but for now...
67 GCH_PS_younger_gens,
68 // Leave this one last.
69 GCH_PS_NumElements
70 };
71
72 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
73 SharedHeap(policy),
74 _gen_policy(policy),
75 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
76 _full_collections_completed(0)
77 {
78 if (_gen_process_strong_tasks == NULL ||
79 !_gen_process_strong_tasks->valid()) {
80 vm_exit_during_initialization("Failed necessary allocation.");
81 }
82 assert(policy != NULL, "Sanity check");
83 _preloading_shared_classes = false;
84 }
85
86 jint GenCollectedHeap::initialize() {
87 CollectedHeap::pre_initialize();
88
89 int i;
90 _n_gens = gen_policy()->number_of_generations();
91
92 // While there are no constraints in the GC code that HeapWordSize
93 // be any particular value, there are multiple other areas in the
94 // system which believe this to be true (e.g. oop->object_size in some
95 // cases incorrectly returns the size in wordSize units rather than
96 // HeapWordSize).
97 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
98
99 // The heap must be at least as aligned as generations.
100 size_t alignment = Generation::GenGrain;
101
102 _gen_specs = gen_policy()->generations();
103 PermanentGenerationSpec *perm_gen_spec =
104 collector_policy()->permanent_generation();
105
106 // Make sure the sizes are all aligned.
107 for (i = 0; i < _n_gens; i++) {
108 _gen_specs[i]->align(alignment);
109 }
110 perm_gen_spec->align(alignment);
111
112 // If we are dumping the heap, then allocate a wasted block of address
113 // space in order to push the heap to a lower address. This extra
114 // address range allows for other (or larger) libraries to be loaded
115 // without them occupying the space required for the shared spaces.
116
117 if (DumpSharedSpaces) {
118 uintx reserved = 0;
119 uintx block_size = 64*1024*1024;
120 while (reserved < SharedDummyBlockSize) {
121 char* dummy = os::reserve_memory(block_size);
122 reserved += block_size;
123 }
124 }
125
126 // Allocate space for the heap.
127
128 char* heap_address;
129 size_t total_reserved = 0;
130 int n_covered_regions = 0;
131 ReservedSpace heap_rs(0);
132
133 heap_address = allocate(alignment, perm_gen_spec, &total_reserved,
134 &n_covered_regions, &heap_rs);
135
136 if (UseSharedSpaces) {
137 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) {
138 if (heap_rs.is_reserved()) {
139 heap_rs.release();
140 }
141 FileMapInfo* mapinfo = FileMapInfo::current_info();
142 mapinfo->fail_continue("Unable to reserve shared region.");
143 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions,
144 &heap_rs);
145 }
146 }
147
148 if (!heap_rs.is_reserved()) {
149 vm_shutdown_during_initialization(
150 "Could not reserve enough space for object heap");
151 return JNI_ENOMEM;
152 }
153
154 _reserved = MemRegion((HeapWord*)heap_rs.base(),
155 (HeapWord*)(heap_rs.base() + heap_rs.size()));
156
157 // It is important to do this in a way such that concurrent readers can't
158 // temporarily think somethings in the heap. (Seen this happen in asserts.)
159 _reserved.set_word_size(0);
160 _reserved.set_start((HeapWord*)heap_rs.base());
161 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size()
162 - perm_gen_spec->misc_code_size();
163 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
164
165 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
166 set_barrier_set(rem_set()->bs());
167
168 _gch = this;
169
170 for (i = 0; i < _n_gens; i++) {
171 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(),
172 UseSharedSpaces, UseSharedSpaces);
173 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
174 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
175 }
176 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set());
177
178 clear_incremental_collection_failed();
179
180 #ifndef SERIALGC
181 // If we are running CMS, create the collector responsible
182 // for collecting the CMS generations.
183 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
184 bool success = create_cms_collector();
185 if (!success) return JNI_ENOMEM;
186 }
187 #endif // SERIALGC
188
189 return JNI_OK;
190 }
191
192
193 char* GenCollectedHeap::allocate(size_t alignment,
194 PermanentGenerationSpec* perm_gen_spec,
195 size_t* _total_reserved,
196 int* _n_covered_regions,
197 ReservedSpace* heap_rs){
198 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
199 "the maximum representable size";
200
201 // Now figure out the total size.
202 size_t total_reserved = 0;
203 int n_covered_regions = 0;
204 const size_t pageSize = UseLargePages ?
205 os::large_page_size() : os::vm_page_size();
206
207 for (int i = 0; i < _n_gens; i++) {
208 total_reserved += _gen_specs[i]->max_size();
209 if (total_reserved < _gen_specs[i]->max_size()) {
210 vm_exit_during_initialization(overflow_msg);
211 }
212 n_covered_regions += _gen_specs[i]->n_covered_regions();
213 }
214 assert(total_reserved % pageSize == 0,
215 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
216 SIZE_FORMAT, total_reserved, pageSize));
217 total_reserved += perm_gen_spec->max_size();
218 assert(total_reserved % pageSize == 0,
219 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize="
220 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved,
221 pageSize, perm_gen_spec->max_size()));
222
223 if (total_reserved < perm_gen_spec->max_size()) {
224 vm_exit_during_initialization(overflow_msg);
225 }
226 n_covered_regions += perm_gen_spec->n_covered_regions();
227
228 // Add the size of the data area which shares the same reserved area
229 // as the heap, but which is not actually part of the heap.
230 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
231
232 total_reserved += s;
233 if (total_reserved < s) {
234 vm_exit_during_initialization(overflow_msg);
235 }
236
237 if (UseLargePages) {
238 assert(total_reserved != 0, "total_reserved cannot be 0");
239 total_reserved = round_to(total_reserved, os::large_page_size());
240 if (total_reserved < os::large_page_size()) {
241 vm_exit_during_initialization(overflow_msg);
242 }
243 }
244
245 // Calculate the address at which the heap must reside in order for
246 // the shared data to be at the required address.
247
248 char* heap_address;
249 if (UseSharedSpaces) {
250
251 // Calculate the address of the first word beyond the heap.
252 FileMapInfo* mapinfo = FileMapInfo::current_info();
253 int lr = CompactingPermGenGen::n_regions - 1;
254 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
255 heap_address = mapinfo->region_base(lr) + capacity;
256
257 // Calculate the address of the first word of the heap.
258 heap_address -= total_reserved;
259 } else {
260 heap_address = NULL; // any address will do.
261 if (UseCompressedOops) {
262 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
263 *_total_reserved = total_reserved;
264 *_n_covered_regions = n_covered_regions;
265 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
266 UseLargePages, heap_address);
267
268 if (heap_address != NULL && !heap_rs->is_reserved()) {
269 // Failed to reserve at specified address - the requested memory
270 // region is taken already, for example, by 'java' launcher.
271 // Try again to reserver heap higher.
272 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
273 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
274 UseLargePages, heap_address);
275
276 if (heap_address != NULL && !heap_rs->is_reserved()) {
277 // Failed to reserve at specified address again - give up.
278 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
279 assert(heap_address == NULL, "");
280 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
281 UseLargePages, heap_address);
282 }
283 }
284 return heap_address;
285 }
286 }
287
288 *_total_reserved = total_reserved;
289 *_n_covered_regions = n_covered_regions;
290 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
291 UseLargePages, heap_address);
292
293 return heap_address;
294 }
295
296
297 void GenCollectedHeap::post_initialize() {
298 SharedHeap::post_initialize();
299 TwoGenerationCollectorPolicy *policy =
300 (TwoGenerationCollectorPolicy *)collector_policy();
301 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
302 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
303 assert(def_new_gen->kind() == Generation::DefNew ||
304 def_new_gen->kind() == Generation::ParNew ||
305 def_new_gen->kind() == Generation::ASParNew,
306 "Wrong generation kind");
307
308 Generation* old_gen = get_gen(1);
309 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
310 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
311 old_gen->kind() == Generation::MarkSweepCompact,
312 "Wrong generation kind");
313
314 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
315 old_gen->capacity(),
316 def_new_gen->from()->capacity());
317 policy->initialize_gc_policy_counters();
318 }
319
320 void GenCollectedHeap::ref_processing_init() {
321 SharedHeap::ref_processing_init();
322 for (int i = 0; i < _n_gens; i++) {
323 _gens[i]->ref_processor_init();
324 }
325 }
326
327 size_t GenCollectedHeap::capacity() const {
328 size_t res = 0;
329 for (int i = 0; i < _n_gens; i++) {
330 res += _gens[i]->capacity();
331 }
332 return res;
333 }
334
335 size_t GenCollectedHeap::used() const {
336 size_t res = 0;
337 for (int i = 0; i < _n_gens; i++) {
338 res += _gens[i]->used();
339 }
340 return res;
341 }
342
343 // Save the "used_region" for generations level and lower,
344 // and, if perm is true, for perm gen.
345 void GenCollectedHeap::save_used_regions(int level, bool perm) {
346 assert(level < _n_gens, "Illegal level parameter");
347 for (int i = level; i >= 0; i--) {
348 _gens[i]->save_used_region();
349 }
350 if (perm) {
351 perm_gen()->save_used_region();
352 }
353 }
354
355 size_t GenCollectedHeap::max_capacity() const {
356 size_t res = 0;
357 for (int i = 0; i < _n_gens; i++) {
358 res += _gens[i]->max_capacity();
359 }
360 return res;
361 }
362
363 // Update the _full_collections_completed counter
364 // at the end of a stop-world full GC.
365 unsigned int GenCollectedHeap::update_full_collections_completed() {
366 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
367 assert(_full_collections_completed <= _total_full_collections,
368 "Can't complete more collections than were started");
369 _full_collections_completed = _total_full_collections;
370 ml.notify_all();
371 return _full_collections_completed;
372 }
373
374 // Update the _full_collections_completed counter, as appropriate,
375 // at the end of a concurrent GC cycle. Note the conditional update
376 // below to allow this method to be called by a concurrent collector
377 // without synchronizing in any manner with the VM thread (which
378 // may already have initiated a STW full collection "concurrently").
379 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
380 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
381 assert((_full_collections_completed <= _total_full_collections) &&
382 (count <= _total_full_collections),
383 "Can't complete more collections than were started");
384 if (count > _full_collections_completed) {
385 _full_collections_completed = count;
386 ml.notify_all();
387 }
388 return _full_collections_completed;
389 }
390
391
392 #ifndef PRODUCT
393 // Override of memory state checking method in CollectedHeap:
394 // Some collectors (CMS for example) can't have badHeapWordVal written
395 // in the first two words of an object. (For instance , in the case of
396 // CMS these words hold state used to synchronize between certain
397 // (concurrent) GC steps and direct allocating mutators.)
398 // The skip_header_HeapWords() method below, allows us to skip
399 // over the requisite number of HeapWord's. Note that (for
400 // generational collectors) this means that those many words are
401 // skipped in each object, irrespective of the generation in which
402 // that object lives. The resultant loss of precision seems to be
403 // harmless and the pain of avoiding that imprecision appears somewhat
404 // higher than we are prepared to pay for such rudimentary debugging
405 // support.
406 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
407 size_t size) {
408 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
409 // We are asked to check a size in HeapWords,
410 // but the memory is mangled in juint words.
411 juint* start = (juint*) (addr + skip_header_HeapWords());
412 juint* end = (juint*) (addr + size);
413 for (juint* slot = start; slot < end; slot += 1) {
414 assert(*slot == badHeapWordVal,
415 "Found non badHeapWordValue in pre-allocation check");
416 }
417 }
418 }
419 #endif
420
421 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
422 bool is_tlab,
423 bool first_only) {
424 HeapWord* res;
425 for (int i = 0; i < _n_gens; i++) {
426 if (_gens[i]->should_allocate(size, is_tlab)) {
427 res = _gens[i]->allocate(size, is_tlab);
428 if (res != NULL) return res;
429 else if (first_only) break;
430 }
431 }
432 // Otherwise...
433 return NULL;
434 }
435
436 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
437 bool* gc_overhead_limit_was_exceeded) {
438 return collector_policy()->mem_allocate_work(size,
439 false /* is_tlab */,
440 gc_overhead_limit_was_exceeded);
441 }
442
443 bool GenCollectedHeap::must_clear_all_soft_refs() {
444 return _gc_cause == GCCause::_last_ditch_collection;
445 }
446
447 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
448 return UseConcMarkSweepGC &&
449 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
450 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
451 }
452
453 void GenCollectedHeap::do_collection(bool full,
454 bool clear_all_soft_refs,
455 size_t size,
456 bool is_tlab,
457 int max_level) {
458 bool prepared_for_verification = false;
459 ResourceMark rm;
460 DEBUG_ONLY(Thread* my_thread = Thread::current();)
461
462 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
463 assert(my_thread->is_VM_thread() ||
464 my_thread->is_ConcurrentGC_thread(),
465 "incorrect thread type capability");
466 assert(Heap_lock->is_locked(),
467 "the requesting thread should have the Heap_lock");
468 guarantee(!is_gc_active(), "collection is not reentrant");
469 assert(max_level < n_gens(), "sanity check");
470
471 if (GC_locker::check_active_before_gc()) {
472 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
473 }
474
475 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
476 collector_policy()->should_clear_all_soft_refs();
477
478 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
479
480 const size_t perm_prev_used = perm_gen()->used();
481
482 print_heap_before_gc();
483
484 {
485 FlagSetting fl(_is_gc_active, true);
486
487 bool complete = full && (max_level == (n_gens()-1));
488 const char* gc_cause_prefix = complete ? "Full GC" : "GC";
489 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
490 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
491 TraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, gclog_or_tty);
492
493 gc_prologue(complete);
494 increment_total_collections(complete);
495
496 size_t gch_prev_used = used();
497
498 int starting_level = 0;
499 if (full) {
500 // Search for the oldest generation which will collect all younger
501 // generations, and start collection loop there.
502 for (int i = max_level; i >= 0; i--) {
503 if (_gens[i]->full_collects_younger_generations()) {
504 starting_level = i;
505 break;
506 }
507 }
508 }
509
510 bool must_restore_marks_for_biased_locking = false;
511
512 int max_level_collected = starting_level;
513 for (int i = starting_level; i <= max_level; i++) {
514 if (_gens[i]->should_collect(full, size, is_tlab)) {
515 if (i == n_gens() - 1) { // a major collection is to happen
516 if (!complete) {
517 // The full_collections increment was missed above.
518 increment_total_full_collections();
519 }
520 pre_full_gc_dump(); // do any pre full gc dumps
521 }
522 // Timer for individual generations. Last argument is false: no CR
523 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty);
524 TraceCollectorStats tcs(_gens[i]->counters());
525 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause());
526
527 size_t prev_used = _gens[i]->used();
528 _gens[i]->stat_record()->invocations++;
529 _gens[i]->stat_record()->accumulated_time.start();
530
531 // Must be done anew before each collection because
532 // a previous collection will do mangling and will
533 // change top of some spaces.
534 record_gen_tops_before_GC();
535
536 if (PrintGC && Verbose) {
537 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
538 i,
539 _gens[i]->stat_record()->invocations,
540 size*HeapWordSize);
541 }
542
543 if (VerifyBeforeGC && i >= VerifyGCLevel &&
544 total_collections() >= VerifyGCStartAt) {
545 HandleMark hm; // Discard invalid handles created during verification
546 if (!prepared_for_verification) {
547 prepare_for_verify();
548 prepared_for_verification = true;
549 }
550 gclog_or_tty->print(" VerifyBeforeGC:");
551 Universe::verify(true);
552 }
553 COMPILER2_PRESENT(DerivedPointerTable::clear());
554
555 if (!must_restore_marks_for_biased_locking &&
556 _gens[i]->performs_in_place_marking()) {
557 // We perform this mark word preservation work lazily
558 // because it's only at this point that we know whether we
559 // absolutely have to do it; we want to avoid doing it for
560 // scavenge-only collections where it's unnecessary
561 must_restore_marks_for_biased_locking = true;
562 BiasedLocking::preserve_marks();
563 }
564
565 // Do collection work
566 {
567 // Note on ref discovery: For what appear to be historical reasons,
568 // GCH enables and disabled (by enqueing) refs discovery.
569 // In the future this should be moved into the generation's
570 // collect method so that ref discovery and enqueueing concerns
571 // are local to a generation. The collect method could return
572 // an appropriate indication in the case that notification on
573 // the ref lock was needed. This will make the treatment of
574 // weak refs more uniform (and indeed remove such concerns
575 // from GCH). XXX
576
577 HandleMark hm; // Discard invalid handles created during gc
578 save_marks(); // save marks for all gens
579 // We want to discover references, but not process them yet.
580 // This mode is disabled in process_discovered_references if the
581 // generation does some collection work, or in
582 // enqueue_discovered_references if the generation returns
583 // without doing any work.
584 ReferenceProcessor* rp = _gens[i]->ref_processor();
585 // If the discovery of ("weak") refs in this generation is
586 // atomic wrt other collectors in this configuration, we
587 // are guaranteed to have empty discovered ref lists.
588 if (rp->discovery_is_atomic()) {
589 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
590 rp->setup_policy(do_clear_all_soft_refs);
591 } else {
592 // collect() below will enable discovery as appropriate
593 }
594 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
595 if (!rp->enqueuing_is_done()) {
596 rp->enqueue_discovered_references();
597 } else {
598 rp->set_enqueuing_is_done(false);
599 }
600 rp->verify_no_references_recorded();
601 }
602 max_level_collected = i;
603
604 // Determine if allocation request was met.
605 if (size > 0) {
606 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
607 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
608 size = 0;
609 }
610 }
611 }
612
613 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
614
615 _gens[i]->stat_record()->accumulated_time.stop();
616
617 update_gc_stats(i, full);
618
619 if (VerifyAfterGC && i >= VerifyGCLevel &&
620 total_collections() >= VerifyGCStartAt) {
621 HandleMark hm; // Discard invalid handles created during verification
622 gclog_or_tty->print(" VerifyAfterGC:");
623 Universe::verify(false);
624 }
625
626 if (PrintGCDetails) {
627 gclog_or_tty->print(":");
628 _gens[i]->print_heap_change(prev_used);
629 }
630 }
631 }
632
633 // Update "complete" boolean wrt what actually transpired --
634 // for instance, a promotion failure could have led to
635 // a whole heap collection.
636 complete = complete || (max_level_collected == n_gens() - 1);
637
638 if (complete) { // We did a "major" collection
639 post_full_gc_dump(); // do any post full gc dumps
640 }
641
642 if (PrintGCDetails) {
643 print_heap_change(gch_prev_used);
644
645 // Print perm gen info for full GC with PrintGCDetails flag.
646 if (complete) {
647 print_perm_heap_change(perm_prev_used);
648 }
649 }
650
651 for (int j = max_level_collected; j >= 0; j -= 1) {
652 // Adjust generation sizes.
653 _gens[j]->compute_new_size();
654 }
655
656 if (complete) {
657 // Ask the permanent generation to adjust size for full collections
658 perm()->compute_new_size();
659 update_full_collections_completed();
660 }
661
662 // Track memory usage and detect low memory after GC finishes
663 MemoryService::track_memory_usage();
664
665 gc_epilogue(complete);
666
667 if (must_restore_marks_for_biased_locking) {
668 BiasedLocking::restore_marks();
669 }
670 }
671
672 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
673 AdaptiveSizePolicyOutput(sp, total_collections());
674
675 print_heap_after_gc();
676
677 #ifdef TRACESPINNING
678 ParallelTaskTerminator::print_termination_counts();
679 #endif
680
681 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) {
682 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum);
683 vm_exit(-1);
684 }
685 }
686
687 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
688 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
689 }
690
691 void GenCollectedHeap::set_par_threads(uint t) {
692 SharedHeap::set_par_threads(t);
693 _gen_process_strong_tasks->set_n_threads(t);
694 }
695
696 void GenCollectedHeap::
697 gen_process_strong_roots(int level,
698 bool younger_gens_as_roots,
699 bool activate_scope,
700 bool collecting_perm_gen,
701 SharedHeap::ScanningOption so,
702 OopsInGenClosure* not_older_gens,
703 bool do_code_roots,
704 OopsInGenClosure* older_gens) {
705 // General strong roots.
706
707 if (!do_code_roots) {
708 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
709 not_older_gens, NULL, older_gens);
710 } else {
711 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
712 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
713 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
714 not_older_gens, &code_roots, older_gens);
715 }
716
717 if (younger_gens_as_roots) {
718 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
719 for (int i = 0; i < level; i++) {
720 not_older_gens->set_generation(_gens[i]);
721 _gens[i]->oop_iterate(not_older_gens);
722 }
723 not_older_gens->reset_generation();
724 }
725 }
726 // When collection is parallel, all threads get to cooperate to do
727 // older-gen scanning.
728 for (int i = level+1; i < _n_gens; i++) {
729 older_gens->set_generation(_gens[i]);
730 rem_set()->younger_refs_iterate(_gens[i], older_gens);
731 older_gens->reset_generation();
732 }
733
734 _gen_process_strong_tasks->all_tasks_completed();
735 }
736
737 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
738 CodeBlobClosure* code_roots,
739 OopClosure* non_root_closure) {
740 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
741 // "Local" "weak" refs
742 for (int i = 0; i < _n_gens; i++) {
743 _gens[i]->ref_processor()->weak_oops_do(root_closure);
744 }
745 }
746
747 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
748 void GenCollectedHeap:: \
749 oop_since_save_marks_iterate(int level, \
750 OopClosureType* cur, \
751 OopClosureType* older) { \
752 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
753 for (int i = level+1; i < n_gens(); i++) { \
754 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
755 } \
756 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
757 }
758
759 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
760
761 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
762
763 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
764 for (int i = level; i < _n_gens; i++) {
765 if (!_gens[i]->no_allocs_since_save_marks()) return false;
766 }
767 return perm_gen()->no_allocs_since_save_marks();
768 }
769
770 bool GenCollectedHeap::supports_inline_contig_alloc() const {
771 return _gens[0]->supports_inline_contig_alloc();
772 }
773
774 HeapWord** GenCollectedHeap::top_addr() const {
775 return _gens[0]->top_addr();
776 }
777
778 HeapWord** GenCollectedHeap::end_addr() const {
779 return _gens[0]->end_addr();
780 }
781
782 size_t GenCollectedHeap::unsafe_max_alloc() {
783 return _gens[0]->unsafe_max_alloc_nogc();
784 }
785
786 // public collection interfaces
787
788 void GenCollectedHeap::collect(GCCause::Cause cause) {
789 if (should_do_concurrent_full_gc(cause)) {
790 #ifndef SERIALGC
791 // mostly concurrent full collection
792 collect_mostly_concurrent(cause);
793 #else // SERIALGC
794 ShouldNotReachHere();
795 #endif // SERIALGC
796 } else {
797 #ifdef ASSERT
798 if (cause == GCCause::_scavenge_alot) {
799 // minor collection only
800 collect(cause, 0);
801 } else {
802 // Stop-the-world full collection
803 collect(cause, n_gens() - 1);
804 }
805 #else
806 // Stop-the-world full collection
807 collect(cause, n_gens() - 1);
808 #endif
809 }
810 }
811
812 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
813 // The caller doesn't have the Heap_lock
814 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
815 MutexLocker ml(Heap_lock);
816 collect_locked(cause, max_level);
817 }
818
819 // This interface assumes that it's being called by the
820 // vm thread. It collects the heap assuming that the
821 // heap lock is already held and that we are executing in
822 // the context of the vm thread.
823 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
824 assert(Thread::current()->is_VM_thread(), "Precondition#1");
825 assert(Heap_lock->is_locked(), "Precondition#2");
826 GCCauseSetter gcs(this, cause);
827 switch (cause) {
828 case GCCause::_heap_inspection:
829 case GCCause::_heap_dump: {
830 HandleMark hm;
831 do_full_collection(false, // don't clear all soft refs
832 n_gens() - 1);
833 break;
834 }
835 default: // XXX FIX ME
836 ShouldNotReachHere(); // Unexpected use of this function
837 }
838 }
839
840 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
841 // The caller has the Heap_lock
842 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
843 collect_locked(cause, n_gens() - 1);
844 }
845
846 // this is the private collection interface
847 // The Heap_lock is expected to be held on entry.
848
849 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
850 if (_preloading_shared_classes) {
851 report_out_of_shared_space(SharedPermGen);
852 }
853 // Read the GC count while holding the Heap_lock
854 unsigned int gc_count_before = total_collections();
855 unsigned int full_gc_count_before = total_full_collections();
856 {
857 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
858 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
859 cause, max_level);
860 VMThread::execute(&op);
861 }
862 }
863
864 #ifndef SERIALGC
865 bool GenCollectedHeap::create_cms_collector() {
866
867 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
868 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
869 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
870 "Unexpected generation kinds");
871 // Skip two header words in the block content verification
872 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
873 CMSCollector* collector = new CMSCollector(
874 (ConcurrentMarkSweepGeneration*)_gens[1],
875 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
876 _rem_set->as_CardTableRS(),
877 (ConcurrentMarkSweepPolicy*) collector_policy());
878
879 if (collector == NULL || !collector->completed_initialization()) {
880 if (collector) {
881 delete collector; // Be nice in embedded situation
882 }
883 vm_shutdown_during_initialization("Could not create CMS collector");
884 return false;
885 }
886 return true; // success
887 }
888
889 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
890 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
891
892 MutexLocker ml(Heap_lock);
893 // Read the GC counts while holding the Heap_lock
894 unsigned int full_gc_count_before = total_full_collections();
895 unsigned int gc_count_before = total_collections();
896 {
897 MutexUnlocker mu(Heap_lock);
898 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
899 VMThread::execute(&op);
900 }
901 }
902 #endif // SERIALGC
903
904
905 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
906 int max_level) {
907 int local_max_level;
908 if (!incremental_collection_will_fail(false /* don't consult_young */) &&
909 gc_cause() == GCCause::_gc_locker) {
910 local_max_level = 0;
911 } else {
912 local_max_level = max_level;
913 }
914
915 do_collection(true /* full */,
916 clear_all_soft_refs /* clear_all_soft_refs */,
917 0 /* size */,
918 false /* is_tlab */,
919 local_max_level /* max_level */);
920 // Hack XXX FIX ME !!!
921 // A scavenge may not have been attempted, or may have
922 // been attempted and failed, because the old gen was too full
923 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
924 incremental_collection_will_fail(false /* don't consult_young */)) {
925 if (PrintGCDetails) {
926 gclog_or_tty->print_cr("GC locker: Trying a full collection "
927 "because scavenge failed");
928 }
929 // This time allow the old gen to be collected as well
930 do_collection(true /* full */,
931 clear_all_soft_refs /* clear_all_soft_refs */,
932 0 /* size */,
933 false /* is_tlab */,
934 n_gens() - 1 /* max_level */);
935 }
936 }
937
938 bool GenCollectedHeap::is_in_young(oop p) {
939 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start();
940 assert(result == _gens[0]->is_in_reserved(p),
941 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, (void*)p));
942 return result;
943 }
944
945 // Returns "TRUE" iff "p" points into the committed areas of the heap.
946 bool GenCollectedHeap::is_in(const void* p) const {
947 #ifndef ASSERT
948 guarantee(VerifyBeforeGC ||
949 VerifyDuringGC ||
950 VerifyBeforeExit ||
951 PrintAssembly ||
952 tty->count() != 0 || // already printing
953 VerifyAfterGC ||
954 VMError::fatal_error_in_progress(), "too expensive");
955
956 #endif
957 // This might be sped up with a cache of the last generation that
958 // answered yes.
959 for (int i = 0; i < _n_gens; i++) {
960 if (_gens[i]->is_in(p)) return true;
961 }
962 if (_perm_gen->as_gen()->is_in(p)) return true;
963 // Otherwise...
964 return false;
965 }
966
967 #ifdef ASSERT
968 // Don't implement this by using is_in_young(). This method is used
969 // in some cases to check that is_in_young() is correct.
970 bool GenCollectedHeap::is_in_partial_collection(const void* p) {
971 assert(is_in_reserved(p) || p == NULL,
972 "Does not work if address is non-null and outside of the heap");
973 // The order of the generations is young (low addr), old, perm (high addr)
974 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL;
975 }
976 #endif
977
978 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
979 for (int i = 0; i < _n_gens; i++) {
980 _gens[i]->oop_iterate(cl);
981 }
982 }
983
984 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
985 for (int i = 0; i < _n_gens; i++) {
986 _gens[i]->oop_iterate(mr, cl);
987 }
988 }
989
990 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
991 for (int i = 0; i < _n_gens; i++) {
992 _gens[i]->object_iterate(cl);
993 }
994 perm_gen()->object_iterate(cl);
995 }
996
997 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
998 for (int i = 0; i < _n_gens; i++) {
999 _gens[i]->safe_object_iterate(cl);
1000 }
1001 perm_gen()->safe_object_iterate(cl);
1002 }
1003
1004 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
1005 for (int i = 0; i < _n_gens; i++) {
1006 _gens[i]->object_iterate_since_last_GC(cl);
1007 }
1008 }
1009
1010 Space* GenCollectedHeap::space_containing(const void* addr) const {
1011 for (int i = 0; i < _n_gens; i++) {
1012 Space* res = _gens[i]->space_containing(addr);
1013 if (res != NULL) return res;
1014 }
1015 Space* res = perm_gen()->space_containing(addr);
1016 if (res != NULL) return res;
1017 // Otherwise...
1018 assert(false, "Could not find containing space");
1019 return NULL;
1020 }
1021
1022
1023 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1024 assert(is_in_reserved(addr), "block_start of address outside of heap");
1025 for (int i = 0; i < _n_gens; i++) {
1026 if (_gens[i]->is_in_reserved(addr)) {
1027 assert(_gens[i]->is_in(addr),
1028 "addr should be in allocated part of generation");
1029 return _gens[i]->block_start(addr);
1030 }
1031 }
1032 if (perm_gen()->is_in_reserved(addr)) {
1033 assert(perm_gen()->is_in(addr),
1034 "addr should be in allocated part of perm gen");
1035 return perm_gen()->block_start(addr);
1036 }
1037 assert(false, "Some generation should contain the address");
1038 return NULL;
1039 }
1040
1041 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1042 assert(is_in_reserved(addr), "block_size of address outside of heap");
1043 for (int i = 0; i < _n_gens; i++) {
1044 if (_gens[i]->is_in_reserved(addr)) {
1045 assert(_gens[i]->is_in(addr),
1046 "addr should be in allocated part of generation");
1047 return _gens[i]->block_size(addr);
1048 }
1049 }
1050 if (perm_gen()->is_in_reserved(addr)) {
1051 assert(perm_gen()->is_in(addr),
1052 "addr should be in allocated part of perm gen");
1053 return perm_gen()->block_size(addr);
1054 }
1055 assert(false, "Some generation should contain the address");
1056 return 0;
1057 }
1058
1059 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1060 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1061 assert(block_start(addr) == addr, "addr must be a block start");
1062 for (int i = 0; i < _n_gens; i++) {
1063 if (_gens[i]->is_in_reserved(addr)) {
1064 return _gens[i]->block_is_obj(addr);
1065 }
1066 }
1067 if (perm_gen()->is_in_reserved(addr)) {
1068 return perm_gen()->block_is_obj(addr);
1069 }
1070 assert(false, "Some generation should contain the address");
1071 return false;
1072 }
1073
1074 bool GenCollectedHeap::supports_tlab_allocation() const {
1075 for (int i = 0; i < _n_gens; i += 1) {
1076 if (_gens[i]->supports_tlab_allocation()) {
1077 return true;
1078 }
1079 }
1080 return false;
1081 }
1082
1083 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1084 size_t result = 0;
1085 for (int i = 0; i < _n_gens; i += 1) {
1086 if (_gens[i]->supports_tlab_allocation()) {
1087 result += _gens[i]->tlab_capacity();
1088 }
1089 }
1090 return result;
1091 }
1092
1093 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1094 size_t result = 0;
1095 for (int i = 0; i < _n_gens; i += 1) {
1096 if (_gens[i]->supports_tlab_allocation()) {
1097 result += _gens[i]->unsafe_max_tlab_alloc();
1098 }
1099 }
1100 return result;
1101 }
1102
1103 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1104 bool gc_overhead_limit_was_exceeded;
1105 return collector_policy()->mem_allocate_work(size /* size */,
1106 true /* is_tlab */,
1107 &gc_overhead_limit_was_exceeded);
1108 }
1109
1110 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1111 // from the list headed by "*prev_ptr".
1112 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1113 bool first = true;
1114 size_t min_size = 0; // "first" makes this conceptually infinite.
1115 ScratchBlock **smallest_ptr, *smallest;
1116 ScratchBlock *cur = *prev_ptr;
1117 while (cur) {
1118 assert(*prev_ptr == cur, "just checking");
1119 if (first || cur->num_words < min_size) {
1120 smallest_ptr = prev_ptr;
1121 smallest = cur;
1122 min_size = smallest->num_words;
1123 first = false;
1124 }
1125 prev_ptr = &cur->next;
1126 cur = cur->next;
1127 }
1128 smallest = *smallest_ptr;
1129 *smallest_ptr = smallest->next;
1130 return smallest;
1131 }
1132
1133 // Sort the scratch block list headed by res into decreasing size order,
1134 // and set "res" to the result.
1135 static void sort_scratch_list(ScratchBlock*& list) {
1136 ScratchBlock* sorted = NULL;
1137 ScratchBlock* unsorted = list;
1138 while (unsorted) {
1139 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1140 smallest->next = sorted;
1141 sorted = smallest;
1142 }
1143 list = sorted;
1144 }
1145
1146 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1147 size_t max_alloc_words) {
1148 ScratchBlock* res = NULL;
1149 for (int i = 0; i < _n_gens; i++) {
1150 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1151 }
1152 sort_scratch_list(res);
1153 return res;
1154 }
1155
1156 void GenCollectedHeap::release_scratch() {
1157 for (int i = 0; i < _n_gens; i++) {
1158 _gens[i]->reset_scratch();
1159 }
1160 }
1161
1162 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1163 void do_generation(Generation* gen) {
1164 gen->prepare_for_verify();
1165 }
1166 };
1167
1168 void GenCollectedHeap::prepare_for_verify() {
1169 ensure_parsability(false); // no need to retire TLABs
1170 GenPrepareForVerifyClosure blk;
1171 generation_iterate(&blk, false);
1172 perm_gen()->prepare_for_verify();
1173 }
1174
1175
1176 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1177 bool old_to_young) {
1178 if (old_to_young) {
1179 for (int i = _n_gens-1; i >= 0; i--) {
1180 cl->do_generation(_gens[i]);
1181 }
1182 } else {
1183 for (int i = 0; i < _n_gens; i++) {
1184 cl->do_generation(_gens[i]);
1185 }
1186 }
1187 }
1188
1189 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1190 for (int i = 0; i < _n_gens; i++) {
1191 _gens[i]->space_iterate(cl, true);
1192 }
1193 perm_gen()->space_iterate(cl, true);
1194 }
1195
1196 bool GenCollectedHeap::is_maximal_no_gc() const {
1197 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1198 if (!_gens[i]->is_maximal_no_gc()) {
1199 return false;
1200 }
1201 }
1202 return true;
1203 }
1204
1205 void GenCollectedHeap::save_marks() {
1206 for (int i = 0; i < _n_gens; i++) {
1207 _gens[i]->save_marks();
1208 }
1209 perm_gen()->save_marks();
1210 }
1211
1212 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1213 for (int i = 0; i <= collectedGen; i++) {
1214 _gens[i]->compute_new_size();
1215 }
1216 }
1217
1218 GenCollectedHeap* GenCollectedHeap::heap() {
1219 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1220 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1221 return _gch;
1222 }
1223
1224
1225 void GenCollectedHeap::prepare_for_compaction() {
1226 Generation* scanning_gen = _gens[_n_gens-1];
1227 // Start by compacting into same gen.
1228 CompactPoint cp(scanning_gen, NULL, NULL);
1229 while (scanning_gen != NULL) {
1230 scanning_gen->prepare_for_compaction(&cp);
1231 scanning_gen = prev_gen(scanning_gen);
1232 }
1233 }
1234
1235 GCStats* GenCollectedHeap::gc_stats(int level) const {
1236 return _gens[level]->gc_stats();
1237 }
1238
1239 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) {
1240 if (!silent) {
1241 gclog_or_tty->print("permgen ");
1242 }
1243 perm_gen()->verify();
1244 for (int i = _n_gens-1; i >= 0; i--) {
1245 Generation* g = _gens[i];
1246 if (!silent) {
1247 gclog_or_tty->print(g->name());
1248 gclog_or_tty->print(" ");
1249 }
1250 g->verify();
1251 }
1252 if (!silent) {
1253 gclog_or_tty->print("remset ");
1254 }
1255 rem_set()->verify();
1256 }
1257
1258 void GenCollectedHeap::print_on(outputStream* st) const {
1259 for (int i = 0; i < _n_gens; i++) {
1260 _gens[i]->print_on(st);
1261 }
1262 perm_gen()->print_on(st);
1263 }
1264
1265 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1266 if (workers() != NULL) {
1267 workers()->threads_do(tc);
1268 }
1269 #ifndef SERIALGC
1270 if (UseConcMarkSweepGC) {
1271 ConcurrentMarkSweepThread::threads_do(tc);
1272 }
1273 #endif // SERIALGC
1274 }
1275
1276 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1277 #ifndef SERIALGC
1278 if (UseParNewGC) {
1279 workers()->print_worker_threads_on(st);
1280 }
1281 if (UseConcMarkSweepGC) {
1282 ConcurrentMarkSweepThread::print_all_on(st);
1283 }
1284 #endif // SERIALGC
1285 }
1286
1287 void GenCollectedHeap::print_tracing_info() const {
1288 if (TraceGen0Time) {
1289 get_gen(0)->print_summary_info();
1290 }
1291 if (TraceGen1Time) {
1292 get_gen(1)->print_summary_info();
1293 }
1294 }
1295
1296 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1297 if (PrintGCDetails && Verbose) {
1298 gclog_or_tty->print(" " SIZE_FORMAT
1299 "->" SIZE_FORMAT
1300 "(" SIZE_FORMAT ")",
1301 prev_used, used(), capacity());
1302 } else {
1303 gclog_or_tty->print(" " SIZE_FORMAT "K"
1304 "->" SIZE_FORMAT "K"
1305 "(" SIZE_FORMAT "K)",
1306 prev_used / K, used() / K, capacity() / K);
1307 }
1308 }
1309
1310 //New method to print perm gen info with PrintGCDetails flag
1311 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1312 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1313 perm_gen()->print_heap_change(perm_prev_used);
1314 gclog_or_tty->print("]");
1315 }
1316
1317 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1318 private:
1319 bool _full;
1320 public:
1321 void do_generation(Generation* gen) {
1322 gen->gc_prologue(_full);
1323 }
1324 GenGCPrologueClosure(bool full) : _full(full) {};
1325 };
1326
1327 void GenCollectedHeap::gc_prologue(bool full) {
1328 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1329
1330 always_do_update_barrier = false;
1331 // Fill TLAB's and such
1332 CollectedHeap::accumulate_statistics_all_tlabs();
1333 ensure_parsability(true); // retire TLABs
1334
1335 // Call allocation profiler
1336 AllocationProfiler::iterate_since_last_gc();
1337 // Walk generations
1338 GenGCPrologueClosure blk(full);
1339 generation_iterate(&blk, false); // not old-to-young.
1340 perm_gen()->gc_prologue(full);
1341 };
1342
1343 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1344 private:
1345 bool _full;
1346 public:
1347 void do_generation(Generation* gen) {
1348 gen->gc_epilogue(_full);
1349 }
1350 GenGCEpilogueClosure(bool full) : _full(full) {};
1351 };
1352
1353 void GenCollectedHeap::gc_epilogue(bool full) {
1354 #ifdef COMPILER2
1355 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1356 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1357 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1358 #endif /* COMPILER2 */
1359
1360 resize_all_tlabs();
1361
1362 GenGCEpilogueClosure blk(full);
1363 generation_iterate(&blk, false); // not old-to-young.
1364 perm_gen()->gc_epilogue(full);
1365
1366 if (!CleanChunkPoolAsync) {
1367 Chunk::clean_chunk_pool();
1368 }
1369
1370 always_do_update_barrier = UseConcMarkSweepGC;
1371 };
1372
1373 #ifndef PRODUCT
1374 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1375 private:
1376 public:
1377 void do_generation(Generation* gen) {
1378 gen->record_spaces_top();
1379 }
1380 };
1381
1382 void GenCollectedHeap::record_gen_tops_before_GC() {
1383 if (ZapUnusedHeapArea) {
1384 GenGCSaveTopsBeforeGCClosure blk;
1385 generation_iterate(&blk, false); // not old-to-young.
1386 perm_gen()->record_spaces_top();
1387 }
1388 }
1389 #endif // not PRODUCT
1390
1391 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1392 public:
1393 void do_generation(Generation* gen) {
1394 gen->ensure_parsability();
1395 }
1396 };
1397
1398 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1399 CollectedHeap::ensure_parsability(retire_tlabs);
1400 GenEnsureParsabilityClosure ep_cl;
1401 generation_iterate(&ep_cl, false);
1402 perm_gen()->ensure_parsability();
1403 }
1404
1405 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1406 oop obj,
1407 size_t obj_size) {
1408 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1409 HeapWord* result = NULL;
1410
1411 // First give each higher generation a chance to allocate the promoted object.
1412 Generation* allocator = next_gen(gen);
1413 if (allocator != NULL) {
1414 do {
1415 result = allocator->allocate(obj_size, false);
1416 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1417 }
1418
1419 if (result == NULL) {
1420 // Then give gen and higher generations a chance to expand and allocate the
1421 // object.
1422 do {
1423 result = gen->expand_and_allocate(obj_size, false);
1424 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1425 }
1426
1427 if (result != NULL) {
1428 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1429 }
1430 return oop(result);
1431 }
1432
1433 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1434 jlong _time; // in ms
1435 jlong _now; // in ms
1436
1437 public:
1438 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1439
1440 jlong time() { return _time; }
1441
1442 void do_generation(Generation* gen) {
1443 _time = MIN2(_time, gen->time_of_last_gc(_now));
1444 }
1445 };
1446
1447 jlong GenCollectedHeap::millis_since_last_gc() {
1448 // We need a monotonically non-deccreasing time in ms but
1449 // os::javaTimeMillis() does not guarantee monotonicity.
1450 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
1451 GenTimeOfLastGCClosure tolgc_cl(now);
1452 // iterate over generations getting the oldest
1453 // time that a generation was collected
1454 generation_iterate(&tolgc_cl, false);
1455 tolgc_cl.do_generation(perm_gen());
1456
1457 // javaTimeNanos() is guaranteed to be monotonically non-decreasing
1458 // provided the underlying platform provides such a time source
1459 // (and it is bug free). So we still have to guard against getting
1460 // back a time later than 'now'.
1461 jlong retVal = now - tolgc_cl.time();
1462 if (retVal < 0) {
1463 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);)
1464 return 0;
1465 }
1466 return retVal;
1467 }