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