1 /*
2 * Copyright (c) 2000, 2010, 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_will_fail();
179 clear_last_incremental_collection_failed();
180
181 #ifndef SERIALGC
182 // If we are running CMS, create the collector responsible
183 // for collecting the CMS generations.
184 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
185 bool success = create_cms_collector();
186 if (!success) return JNI_ENOMEM;
187 }
188 #endif // SERIALGC
189
190 return JNI_OK;
191 }
192
193
194 char* GenCollectedHeap::allocate(size_t alignment,
195 PermanentGenerationSpec* perm_gen_spec,
196 size_t* _total_reserved,
197 int* _n_covered_regions,
198 ReservedSpace* heap_rs){
199 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
200 "the maximum representable size";
201
202 // Now figure out the total size.
203 size_t total_reserved = 0;
204 int n_covered_regions = 0;
205 const size_t pageSize = UseLargePages ?
206 os::large_page_size() : os::vm_page_size();
207
208 for (int i = 0; i < _n_gens; i++) {
209 total_reserved += _gen_specs[i]->max_size();
210 if (total_reserved < _gen_specs[i]->max_size()) {
211 vm_exit_during_initialization(overflow_msg);
212 }
213 n_covered_regions += _gen_specs[i]->n_covered_regions();
214 }
215 assert(total_reserved % pageSize == 0,
216 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
217 SIZE_FORMAT, total_reserved, pageSize));
218 total_reserved += perm_gen_spec->max_size();
219 assert(total_reserved % pageSize == 0,
220 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize="
221 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved,
222 pageSize, perm_gen_spec->max_size()));
223
224 if (total_reserved < perm_gen_spec->max_size()) {
225 vm_exit_during_initialization(overflow_msg);
226 }
227 n_covered_regions += perm_gen_spec->n_covered_regions();
228
229 // Add the size of the data area which shares the same reserved area
230 // as the heap, but which is not actually part of the heap.
231 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
232
233 total_reserved += s;
234 if (total_reserved < s) {
235 vm_exit_during_initialization(overflow_msg);
236 }
237
238 if (UseLargePages) {
239 assert(total_reserved != 0, "total_reserved cannot be 0");
240 total_reserved = round_to(total_reserved, os::large_page_size());
241 if (total_reserved < os::large_page_size()) {
242 vm_exit_during_initialization(overflow_msg);
243 }
244 }
245
246 // Calculate the address at which the heap must reside in order for
247 // the shared data to be at the required address.
248
249 char* heap_address;
250 if (UseSharedSpaces) {
251
252 // Calculate the address of the first word beyond the heap.
253 FileMapInfo* mapinfo = FileMapInfo::current_info();
254 int lr = CompactingPermGenGen::n_regions - 1;
255 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
256 heap_address = mapinfo->region_base(lr) + capacity;
257
258 // Calculate the address of the first word of the heap.
259 heap_address -= total_reserved;
260 } else {
261 heap_address = NULL; // any address will do.
262 if (UseCompressedOops) {
263 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
264 *_total_reserved = total_reserved;
265 *_n_covered_regions = n_covered_regions;
266 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
267 UseLargePages, heap_address);
268
269 if (heap_address != NULL && !heap_rs->is_reserved()) {
270 // Failed to reserve at specified address - the requested memory
271 // region is taken already, for example, by 'java' launcher.
272 // Try again to reserver heap higher.
273 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
274 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
275 UseLargePages, heap_address);
276
277 if (heap_address != NULL && !heap_rs->is_reserved()) {
278 // Failed to reserve at specified address again - give up.
279 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
280 assert(heap_address == NULL, "");
281 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
282 UseLargePages, heap_address);
283 }
284 }
285 return heap_address;
286 }
287 }
288
289 *_total_reserved = total_reserved;
290 *_n_covered_regions = n_covered_regions;
291 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
292 UseLargePages, heap_address);
293
294 return heap_address;
295 }
296
297
298 void GenCollectedHeap::post_initialize() {
299 SharedHeap::post_initialize();
300 TwoGenerationCollectorPolicy *policy =
301 (TwoGenerationCollectorPolicy *)collector_policy();
302 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
303 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
304 assert(def_new_gen->kind() == Generation::DefNew ||
305 def_new_gen->kind() == Generation::ParNew ||
306 def_new_gen->kind() == Generation::ASParNew,
307 "Wrong generation kind");
308
309 Generation* old_gen = get_gen(1);
310 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
311 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
312 old_gen->kind() == Generation::MarkSweepCompact,
313 "Wrong generation kind");
314
315 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
316 old_gen->capacity(),
317 def_new_gen->from()->capacity());
318 policy->initialize_gc_policy_counters();
319 }
320
321 void GenCollectedHeap::ref_processing_init() {
322 SharedHeap::ref_processing_init();
323 for (int i = 0; i < _n_gens; i++) {
324 _gens[i]->ref_processor_init();
325 }
326 }
327
328 size_t GenCollectedHeap::capacity() const {
329 size_t res = 0;
330 for (int i = 0; i < _n_gens; i++) {
331 res += _gens[i]->capacity();
332 }
333 return res;
334 }
335
336 size_t GenCollectedHeap::used() const {
337 size_t res = 0;
338 for (int i = 0; i < _n_gens; i++) {
339 res += _gens[i]->used();
340 }
341 return res;
342 }
343
344 // Save the "used_region" for generations level and lower,
345 // and, if perm is true, for perm gen.
346 void GenCollectedHeap::save_used_regions(int level, bool perm) {
347 assert(level < _n_gens, "Illegal level parameter");
348 for (int i = level; i >= 0; i--) {
349 _gens[i]->save_used_region();
350 }
351 if (perm) {
352 perm_gen()->save_used_region();
353 }
354 }
355
356 size_t GenCollectedHeap::max_capacity() const {
357 size_t res = 0;
358 for (int i = 0; i < _n_gens; i++) {
359 res += _gens[i]->max_capacity();
360 }
361 return res;
362 }
363
364 // Update the _full_collections_completed counter
365 // at the end of a stop-world full GC.
366 unsigned int GenCollectedHeap::update_full_collections_completed() {
367 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
368 assert(_full_collections_completed <= _total_full_collections,
369 "Can't complete more collections than were started");
370 _full_collections_completed = _total_full_collections;
371 ml.notify_all();
372 return _full_collections_completed;
373 }
374
375 // Update the _full_collections_completed counter, as appropriate,
376 // at the end of a concurrent GC cycle. Note the conditional update
377 // below to allow this method to be called by a concurrent collector
378 // without synchronizing in any manner with the VM thread (which
379 // may already have initiated a STW full collection "concurrently").
380 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
381 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
382 assert((_full_collections_completed <= _total_full_collections) &&
383 (count <= _total_full_collections),
384 "Can't complete more collections than were started");
385 if (count > _full_collections_completed) {
386 _full_collections_completed = count;
387 ml.notify_all();
388 }
389 return _full_collections_completed;
390 }
391
392
393 #ifndef PRODUCT
394 // Override of memory state checking method in CollectedHeap:
395 // Some collectors (CMS for example) can't have badHeapWordVal written
396 // in the first two words of an object. (For instance , in the case of
397 // CMS these words hold state used to synchronize between certain
398 // (concurrent) GC steps and direct allocating mutators.)
399 // The skip_header_HeapWords() method below, allows us to skip
400 // over the requisite number of HeapWord's. Note that (for
401 // generational collectors) this means that those many words are
402 // skipped in each object, irrespective of the generation in which
403 // that object lives. The resultant loss of precision seems to be
404 // harmless and the pain of avoiding that imprecision appears somewhat
405 // higher than we are prepared to pay for such rudimentary debugging
406 // support.
407 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
408 size_t size) {
409 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
410 // We are asked to check a size in HeapWords,
411 // but the memory is mangled in juint words.
412 juint* start = (juint*) (addr + skip_header_HeapWords());
413 juint* end = (juint*) (addr + size);
414 for (juint* slot = start; slot < end; slot += 1) {
415 assert(*slot == badHeapWordVal,
416 "Found non badHeapWordValue in pre-allocation check");
417 }
418 }
419 }
420 #endif
421
422 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
423 bool is_tlab,
424 bool first_only) {
425 HeapWord* res;
426 for (int i = 0; i < _n_gens; i++) {
427 if (_gens[i]->should_allocate(size, is_tlab)) {
428 res = _gens[i]->allocate(size, is_tlab);
429 if (res != NULL) return res;
430 else if (first_only) break;
431 }
432 }
433 // Otherwise...
434 return NULL;
435 }
436
437 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
438 bool is_large_noref,
439 bool is_tlab,
440 bool* gc_overhead_limit_was_exceeded) {
441 return collector_policy()->mem_allocate_work(size,
442 is_tlab,
443 gc_overhead_limit_was_exceeded);
444 }
445
446 bool GenCollectedHeap::must_clear_all_soft_refs() {
447 return _gc_cause == GCCause::_last_ditch_collection;
448 }
449
450 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
451 return UseConcMarkSweepGC &&
452 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
453 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
454 }
455
456 void GenCollectedHeap::do_collection(bool full,
457 bool clear_all_soft_refs,
458 size_t size,
459 bool is_tlab,
460 int max_level) {
461 bool prepared_for_verification = false;
462 ResourceMark rm;
463 DEBUG_ONLY(Thread* my_thread = Thread::current();)
464
465 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
466 assert(my_thread->is_VM_thread() ||
467 my_thread->is_ConcurrentGC_thread(),
468 "incorrect thread type capability");
469 assert(Heap_lock->is_locked(),
470 "the requesting thread should have the Heap_lock");
471 guarantee(!is_gc_active(), "collection is not reentrant");
472 assert(max_level < n_gens(), "sanity check");
473
474 if (GC_locker::check_active_before_gc()) {
475 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
476 }
477
478 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
479 collector_policy()->should_clear_all_soft_refs();
480
481 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
482
483 const size_t perm_prev_used = perm_gen()->used();
484
485 if (PrintHeapAtGC) {
486 Universe::print_heap_before_gc();
487 if (Verbose) {
488 gclog_or_tty->print_cr("GC Cause: %s", GCCause::to_string(gc_cause()));
489 }
490 }
491
492 {
493 FlagSetting fl(_is_gc_active, true);
494
495 bool complete = full && (max_level == (n_gens()-1));
496 const char* gc_cause_str = "GC ";
497 if (complete) {
498 GCCause::Cause cause = gc_cause();
499 if (cause == GCCause::_java_lang_system_gc) {
500 gc_cause_str = "Full GC (System) ";
501 } else {
502 gc_cause_str = "Full GC ";
503 }
504 }
505 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
506 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
507 TraceTime t(gc_cause_str, PrintGCDetails, false, gclog_or_tty);
508
509 gc_prologue(complete);
510 increment_total_collections(complete);
511
512 size_t gch_prev_used = used();
513
514 int starting_level = 0;
515 if (full) {
516 // Search for the oldest generation which will collect all younger
517 // generations, and start collection loop there.
518 for (int i = max_level; i >= 0; i--) {
519 if (_gens[i]->full_collects_younger_generations()) {
520 starting_level = i;
521 break;
522 }
523 }
524 }
525
526 bool must_restore_marks_for_biased_locking = false;
527
528 int max_level_collected = starting_level;
529 for (int i = starting_level; i <= max_level; i++) {
530 if (_gens[i]->should_collect(full, size, is_tlab)) {
531 if (i == n_gens() - 1) { // a major collection is to happen
532 if (!complete) {
533 // The full_collections increment was missed above.
534 increment_total_full_collections();
535 }
536 pre_full_gc_dump(); // do any pre full gc dumps
537 }
538 // Timer for individual generations. Last argument is false: no CR
539 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty);
540 TraceCollectorStats tcs(_gens[i]->counters());
541 TraceMemoryManagerStats tmms(_gens[i]->kind());
542
543 size_t prev_used = _gens[i]->used();
544 _gens[i]->stat_record()->invocations++;
545 _gens[i]->stat_record()->accumulated_time.start();
546
547 // Must be done anew before each collection because
548 // a previous collection will do mangling and will
549 // change top of some spaces.
550 record_gen_tops_before_GC();
551
552 if (PrintGC && Verbose) {
553 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
554 i,
555 _gens[i]->stat_record()->invocations,
556 size*HeapWordSize);
557 }
558
559 if (VerifyBeforeGC && i >= VerifyGCLevel &&
560 total_collections() >= VerifyGCStartAt) {
561 HandleMark hm; // Discard invalid handles created during verification
562 if (!prepared_for_verification) {
563 prepare_for_verify();
564 prepared_for_verification = true;
565 }
566 gclog_or_tty->print(" VerifyBeforeGC:");
567 Universe::verify(true);
568 }
569 COMPILER2_PRESENT(DerivedPointerTable::clear());
570
571 if (!must_restore_marks_for_biased_locking &&
572 _gens[i]->performs_in_place_marking()) {
573 // We perform this mark word preservation work lazily
574 // because it's only at this point that we know whether we
575 // absolutely have to do it; we want to avoid doing it for
576 // scavenge-only collections where it's unnecessary
577 must_restore_marks_for_biased_locking = true;
578 BiasedLocking::preserve_marks();
579 }
580
581 // Do collection work
582 {
583 // Note on ref discovery: For what appear to be historical reasons,
584 // GCH enables and disabled (by enqueing) refs discovery.
585 // In the future this should be moved into the generation's
586 // collect method so that ref discovery and enqueueing concerns
587 // are local to a generation. The collect method could return
588 // an appropriate indication in the case that notification on
589 // the ref lock was needed. This will make the treatment of
590 // weak refs more uniform (and indeed remove such concerns
591 // from GCH). XXX
592
593 HandleMark hm; // Discard invalid handles created during gc
594 save_marks(); // save marks for all gens
595 // We want to discover references, but not process them yet.
596 // This mode is disabled in process_discovered_references if the
597 // generation does some collection work, or in
598 // enqueue_discovered_references if the generation returns
599 // without doing any work.
600 ReferenceProcessor* rp = _gens[i]->ref_processor();
601 // If the discovery of ("weak") refs in this generation is
602 // atomic wrt other collectors in this configuration, we
603 // are guaranteed to have empty discovered ref lists.
604 if (rp->discovery_is_atomic()) {
605 rp->verify_no_references_recorded();
606 rp->enable_discovery();
607 rp->setup_policy(do_clear_all_soft_refs);
608 } else {
609 // collect() below will enable discovery as appropriate
610 }
611 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
612 if (!rp->enqueuing_is_done()) {
613 rp->enqueue_discovered_references();
614 } else {
615 rp->set_enqueuing_is_done(false);
616 }
617 rp->verify_no_references_recorded();
618 }
619 max_level_collected = i;
620
621 // Determine if allocation request was met.
622 if (size > 0) {
623 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
624 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
625 size = 0;
626 }
627 }
628 }
629
630 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
631
632 _gens[i]->stat_record()->accumulated_time.stop();
633
634 update_gc_stats(i, full);
635
636 if (VerifyAfterGC && i >= VerifyGCLevel &&
637 total_collections() >= VerifyGCStartAt) {
638 HandleMark hm; // Discard invalid handles created during verification
639 gclog_or_tty->print(" VerifyAfterGC:");
640 Universe::verify(false);
641 }
642
643 if (PrintGCDetails) {
644 gclog_or_tty->print(":");
645 _gens[i]->print_heap_change(prev_used);
646 }
647 }
648 }
649
650 // Update "complete" boolean wrt what actually transpired --
651 // for instance, a promotion failure could have led to
652 // a whole heap collection.
653 complete = complete || (max_level_collected == n_gens() - 1);
654
655 if (complete) { // We did a "major" collection
656 post_full_gc_dump(); // do any post full gc dumps
657 }
658
659 if (PrintGCDetails) {
660 print_heap_change(gch_prev_used);
661
662 // Print perm gen info for full GC with PrintGCDetails flag.
663 if (complete) {
664 print_perm_heap_change(perm_prev_used);
665 }
666 }
667
668 for (int j = max_level_collected; j >= 0; j -= 1) {
669 // Adjust generation sizes.
670 _gens[j]->compute_new_size();
671 }
672
673 if (complete) {
674 // Ask the permanent generation to adjust size for full collections
675 perm()->compute_new_size();
676 update_full_collections_completed();
677 }
678
679 // Track memory usage and detect low memory after GC finishes
680 MemoryService::track_memory_usage();
681
682 gc_epilogue(complete);
683
684 if (must_restore_marks_for_biased_locking) {
685 BiasedLocking::restore_marks();
686 }
687 }
688
689 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
690 AdaptiveSizePolicyOutput(sp, total_collections());
691
692 if (PrintHeapAtGC) {
693 Universe::print_heap_after_gc();
694 }
695
696 #ifdef TRACESPINNING
697 ParallelTaskTerminator::print_termination_counts();
698 #endif
699
700 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) {
701 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum);
702 vm_exit(-1);
703 }
704 }
705
706 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
707 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
708 }
709
710 void GenCollectedHeap::set_par_threads(int t) {
711 SharedHeap::set_par_threads(t);
712 _gen_process_strong_tasks->set_par_threads(t);
713 }
714
715 class AssertIsPermClosure: public OopClosure {
716 public:
717 void do_oop(oop* p) {
718 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
719 }
720 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
721 };
722 static AssertIsPermClosure assert_is_perm_closure;
723
724 void GenCollectedHeap::
725 gen_process_strong_roots(int level,
726 bool younger_gens_as_roots,
727 bool activate_scope,
728 bool collecting_perm_gen,
729 SharedHeap::ScanningOption so,
730 OopsInGenClosure* not_older_gens,
731 bool do_code_roots,
732 OopsInGenClosure* older_gens) {
733 // General strong roots.
734
735 if (!do_code_roots) {
736 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
737 not_older_gens, NULL, older_gens);
738 } else {
739 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
740 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
741 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
742 not_older_gens, &code_roots, older_gens);
743 }
744
745 if (younger_gens_as_roots) {
746 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
747 for (int i = 0; i < level; i++) {
748 not_older_gens->set_generation(_gens[i]);
749 _gens[i]->oop_iterate(not_older_gens);
750 }
751 not_older_gens->reset_generation();
752 }
753 }
754 // When collection is parallel, all threads get to cooperate to do
755 // older-gen scanning.
756 for (int i = level+1; i < _n_gens; i++) {
757 older_gens->set_generation(_gens[i]);
758 rem_set()->younger_refs_iterate(_gens[i], older_gens);
759 older_gens->reset_generation();
760 }
761
762 _gen_process_strong_tasks->all_tasks_completed();
763 }
764
765 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
766 CodeBlobClosure* code_roots,
767 OopClosure* non_root_closure) {
768 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
769 // "Local" "weak" refs
770 for (int i = 0; i < _n_gens; i++) {
771 _gens[i]->ref_processor()->weak_oops_do(root_closure);
772 }
773 }
774
775 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
776 void GenCollectedHeap:: \
777 oop_since_save_marks_iterate(int level, \
778 OopClosureType* cur, \
779 OopClosureType* older) { \
780 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
781 for (int i = level+1; i < n_gens(); i++) { \
782 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
783 } \
784 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
785 }
786
787 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
788
789 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
790
791 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
792 for (int i = level; i < _n_gens; i++) {
793 if (!_gens[i]->no_allocs_since_save_marks()) return false;
794 }
795 return perm_gen()->no_allocs_since_save_marks();
796 }
797
798 bool GenCollectedHeap::supports_inline_contig_alloc() const {
799 return _gens[0]->supports_inline_contig_alloc();
800 }
801
802 HeapWord** GenCollectedHeap::top_addr() const {
803 return _gens[0]->top_addr();
804 }
805
806 HeapWord** GenCollectedHeap::end_addr() const {
807 return _gens[0]->end_addr();
808 }
809
810 size_t GenCollectedHeap::unsafe_max_alloc() {
811 return _gens[0]->unsafe_max_alloc_nogc();
812 }
813
814 // public collection interfaces
815
816 void GenCollectedHeap::collect(GCCause::Cause cause) {
817 if (should_do_concurrent_full_gc(cause)) {
818 #ifndef SERIALGC
819 // mostly concurrent full collection
820 collect_mostly_concurrent(cause);
821 #else // SERIALGC
822 ShouldNotReachHere();
823 #endif // SERIALGC
824 } else {
825 #ifdef ASSERT
826 if (cause == GCCause::_scavenge_alot) {
827 // minor collection only
828 collect(cause, 0);
829 } else {
830 // Stop-the-world full collection
831 collect(cause, n_gens() - 1);
832 }
833 #else
834 // Stop-the-world full collection
835 collect(cause, n_gens() - 1);
836 #endif
837 }
838 }
839
840 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
841 // The caller doesn't have the Heap_lock
842 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
843 MutexLocker ml(Heap_lock);
844 collect_locked(cause, max_level);
845 }
846
847 // This interface assumes that it's being called by the
848 // vm thread. It collects the heap assuming that the
849 // heap lock is already held and that we are executing in
850 // the context of the vm thread.
851 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
852 assert(Thread::current()->is_VM_thread(), "Precondition#1");
853 assert(Heap_lock->is_locked(), "Precondition#2");
854 GCCauseSetter gcs(this, cause);
855 switch (cause) {
856 case GCCause::_heap_inspection:
857 case GCCause::_heap_dump: {
858 HandleMark hm;
859 do_full_collection(false, // don't clear all soft refs
860 n_gens() - 1);
861 break;
862 }
863 default: // XXX FIX ME
864 ShouldNotReachHere(); // Unexpected use of this function
865 }
866 }
867
868 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
869 // The caller has the Heap_lock
870 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
871 collect_locked(cause, n_gens() - 1);
872 }
873
874 // this is the private collection interface
875 // The Heap_lock is expected to be held on entry.
876
877 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
878 if (_preloading_shared_classes) {
879 warning("\nThe permanent generation is not large enough to preload "
880 "requested classes.\nUse -XX:PermSize= to increase the initial "
881 "size of the permanent generation.\n");
882 vm_exit(2);
883 }
884 // Read the GC count while holding the Heap_lock
885 unsigned int gc_count_before = total_collections();
886 unsigned int full_gc_count_before = total_full_collections();
887 {
888 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
889 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
890 cause, max_level);
891 VMThread::execute(&op);
892 }
893 }
894
895 #ifndef SERIALGC
896 bool GenCollectedHeap::create_cms_collector() {
897
898 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
899 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
900 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
901 "Unexpected generation kinds");
902 // Skip two header words in the block content verification
903 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
904 CMSCollector* collector = new CMSCollector(
905 (ConcurrentMarkSweepGeneration*)_gens[1],
906 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
907 _rem_set->as_CardTableRS(),
908 (ConcurrentMarkSweepPolicy*) collector_policy());
909
910 if (collector == NULL || !collector->completed_initialization()) {
911 if (collector) {
912 delete collector; // Be nice in embedded situation
913 }
914 vm_shutdown_during_initialization("Could not create CMS collector");
915 return false;
916 }
917 return true; // success
918 }
919
920 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
921 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
922
923 MutexLocker ml(Heap_lock);
924 // Read the GC counts while holding the Heap_lock
925 unsigned int full_gc_count_before = total_full_collections();
926 unsigned int gc_count_before = total_collections();
927 {
928 MutexUnlocker mu(Heap_lock);
929 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
930 VMThread::execute(&op);
931 }
932 }
933 #endif // SERIALGC
934
935
936 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
937 int max_level) {
938 int local_max_level;
939 if (!incremental_collection_will_fail() &&
940 gc_cause() == GCCause::_gc_locker) {
941 local_max_level = 0;
942 } else {
943 local_max_level = max_level;
944 }
945
946 do_collection(true /* full */,
947 clear_all_soft_refs /* clear_all_soft_refs */,
948 0 /* size */,
949 false /* is_tlab */,
950 local_max_level /* max_level */);
951 // Hack XXX FIX ME !!!
952 // A scavenge may not have been attempted, or may have
953 // been attempted and failed, because the old gen was too full
954 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
955 incremental_collection_will_fail()) {
956 if (PrintGCDetails) {
957 gclog_or_tty->print_cr("GC locker: Trying a full collection "
958 "because scavenge failed");
959 }
960 // This time allow the old gen to be collected as well
961 do_collection(true /* full */,
962 clear_all_soft_refs /* clear_all_soft_refs */,
963 0 /* size */,
964 false /* is_tlab */,
965 n_gens() - 1 /* max_level */);
966 }
967 }
968
969 // Returns "TRUE" iff "p" points into the allocated area of the heap.
970 bool GenCollectedHeap::is_in(const void* p) const {
971 #ifndef ASSERT
972 guarantee(VerifyBeforeGC ||
973 VerifyDuringGC ||
974 VerifyBeforeExit ||
975 PrintAssembly ||
976 tty->count() != 0 || // already printing
977 VerifyAfterGC ||
978 VMError::fatal_error_in_progress(), "too expensive");
979
980 #endif
981 // This might be sped up with a cache of the last generation that
982 // answered yes.
983 for (int i = 0; i < _n_gens; i++) {
984 if (_gens[i]->is_in(p)) return true;
985 }
986 if (_perm_gen->as_gen()->is_in(p)) return true;
987 // Otherwise...
988 return false;
989 }
990
991 // Returns "TRUE" iff "p" points into the allocated area of the heap.
992 bool GenCollectedHeap::is_in_youngest(void* p) {
993 return _gens[0]->is_in(p);
994 }
995
996 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
997 for (int i = 0; i < _n_gens; i++) {
998 _gens[i]->oop_iterate(cl);
999 }
1000 }
1001
1002 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
1003 for (int i = 0; i < _n_gens; i++) {
1004 _gens[i]->oop_iterate(mr, cl);
1005 }
1006 }
1007
1008 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
1009 for (int i = 0; i < _n_gens; i++) {
1010 _gens[i]->object_iterate(cl);
1011 }
1012 perm_gen()->object_iterate(cl);
1013 }
1014
1015 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
1016 for (int i = 0; i < _n_gens; i++) {
1017 _gens[i]->safe_object_iterate(cl);
1018 }
1019 perm_gen()->safe_object_iterate(cl);
1020 }
1021
1022 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
1023 for (int i = 0; i < _n_gens; i++) {
1024 _gens[i]->object_iterate_since_last_GC(cl);
1025 }
1026 }
1027
1028 Space* GenCollectedHeap::space_containing(const void* addr) const {
1029 for (int i = 0; i < _n_gens; i++) {
1030 Space* res = _gens[i]->space_containing(addr);
1031 if (res != NULL) return res;
1032 }
1033 Space* res = perm_gen()->space_containing(addr);
1034 if (res != NULL) return res;
1035 // Otherwise...
1036 assert(false, "Could not find containing space");
1037 return NULL;
1038 }
1039
1040
1041 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1042 assert(is_in_reserved(addr), "block_start 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_start(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_start(addr);
1054 }
1055 assert(false, "Some generation should contain the address");
1056 return NULL;
1057 }
1058
1059 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1060 assert(is_in_reserved(addr), "block_size of address outside of heap");
1061 for (int i = 0; i < _n_gens; i++) {
1062 if (_gens[i]->is_in_reserved(addr)) {
1063 assert(_gens[i]->is_in(addr),
1064 "addr should be in allocated part of generation");
1065 return _gens[i]->block_size(addr);
1066 }
1067 }
1068 if (perm_gen()->is_in_reserved(addr)) {
1069 assert(perm_gen()->is_in(addr),
1070 "addr should be in allocated part of perm gen");
1071 return perm_gen()->block_size(addr);
1072 }
1073 assert(false, "Some generation should contain the address");
1074 return 0;
1075 }
1076
1077 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1078 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1079 assert(block_start(addr) == addr, "addr must be a block start");
1080 for (int i = 0; i < _n_gens; i++) {
1081 if (_gens[i]->is_in_reserved(addr)) {
1082 return _gens[i]->block_is_obj(addr);
1083 }
1084 }
1085 if (perm_gen()->is_in_reserved(addr)) {
1086 return perm_gen()->block_is_obj(addr);
1087 }
1088 assert(false, "Some generation should contain the address");
1089 return false;
1090 }
1091
1092 bool GenCollectedHeap::supports_tlab_allocation() const {
1093 for (int i = 0; i < _n_gens; i += 1) {
1094 if (_gens[i]->supports_tlab_allocation()) {
1095 return true;
1096 }
1097 }
1098 return false;
1099 }
1100
1101 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1102 size_t result = 0;
1103 for (int i = 0; i < _n_gens; i += 1) {
1104 if (_gens[i]->supports_tlab_allocation()) {
1105 result += _gens[i]->tlab_capacity();
1106 }
1107 }
1108 return result;
1109 }
1110
1111 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1112 size_t result = 0;
1113 for (int i = 0; i < _n_gens; i += 1) {
1114 if (_gens[i]->supports_tlab_allocation()) {
1115 result += _gens[i]->unsafe_max_tlab_alloc();
1116 }
1117 }
1118 return result;
1119 }
1120
1121 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1122 bool gc_overhead_limit_was_exceeded;
1123 HeapWord* result = mem_allocate(size /* size */,
1124 false /* is_large_noref */,
1125 true /* is_tlab */,
1126 &gc_overhead_limit_was_exceeded);
1127 return result;
1128 }
1129
1130 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1131 // from the list headed by "*prev_ptr".
1132 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1133 bool first = true;
1134 size_t min_size = 0; // "first" makes this conceptually infinite.
1135 ScratchBlock **smallest_ptr, *smallest;
1136 ScratchBlock *cur = *prev_ptr;
1137 while (cur) {
1138 assert(*prev_ptr == cur, "just checking");
1139 if (first || cur->num_words < min_size) {
1140 smallest_ptr = prev_ptr;
1141 smallest = cur;
1142 min_size = smallest->num_words;
1143 first = false;
1144 }
1145 prev_ptr = &cur->next;
1146 cur = cur->next;
1147 }
1148 smallest = *smallest_ptr;
1149 *smallest_ptr = smallest->next;
1150 return smallest;
1151 }
1152
1153 // Sort the scratch block list headed by res into decreasing size order,
1154 // and set "res" to the result.
1155 static void sort_scratch_list(ScratchBlock*& list) {
1156 ScratchBlock* sorted = NULL;
1157 ScratchBlock* unsorted = list;
1158 while (unsorted) {
1159 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1160 smallest->next = sorted;
1161 sorted = smallest;
1162 }
1163 list = sorted;
1164 }
1165
1166 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1167 size_t max_alloc_words) {
1168 ScratchBlock* res = NULL;
1169 for (int i = 0; i < _n_gens; i++) {
1170 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1171 }
1172 sort_scratch_list(res);
1173 return res;
1174 }
1175
1176 void GenCollectedHeap::release_scratch() {
1177 for (int i = 0; i < _n_gens; i++) {
1178 _gens[i]->reset_scratch();
1179 }
1180 }
1181
1182 size_t GenCollectedHeap::large_typearray_limit() {
1183 return gen_policy()->large_typearray_limit();
1184 }
1185
1186 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1187 void do_generation(Generation* gen) {
1188 gen->prepare_for_verify();
1189 }
1190 };
1191
1192 void GenCollectedHeap::prepare_for_verify() {
1193 ensure_parsability(false); // no need to retire TLABs
1194 GenPrepareForVerifyClosure blk;
1195 generation_iterate(&blk, false);
1196 perm_gen()->prepare_for_verify();
1197 }
1198
1199
1200 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1201 bool old_to_young) {
1202 if (old_to_young) {
1203 for (int i = _n_gens-1; i >= 0; i--) {
1204 cl->do_generation(_gens[i]);
1205 }
1206 } else {
1207 for (int i = 0; i < _n_gens; i++) {
1208 cl->do_generation(_gens[i]);
1209 }
1210 }
1211 }
1212
1213 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1214 for (int i = 0; i < _n_gens; i++) {
1215 _gens[i]->space_iterate(cl, true);
1216 }
1217 perm_gen()->space_iterate(cl, true);
1218 }
1219
1220 bool GenCollectedHeap::is_maximal_no_gc() const {
1221 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1222 if (!_gens[i]->is_maximal_no_gc()) {
1223 return false;
1224 }
1225 }
1226 return true;
1227 }
1228
1229 void GenCollectedHeap::save_marks() {
1230 for (int i = 0; i < _n_gens; i++) {
1231 _gens[i]->save_marks();
1232 }
1233 perm_gen()->save_marks();
1234 }
1235
1236 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1237 for (int i = 0; i <= collectedGen; i++) {
1238 _gens[i]->compute_new_size();
1239 }
1240 }
1241
1242 GenCollectedHeap* GenCollectedHeap::heap() {
1243 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1244 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1245 return _gch;
1246 }
1247
1248
1249 void GenCollectedHeap::prepare_for_compaction() {
1250 Generation* scanning_gen = _gens[_n_gens-1];
1251 // Start by compacting into same gen.
1252 CompactPoint cp(scanning_gen, NULL, NULL);
1253 while (scanning_gen != NULL) {
1254 scanning_gen->prepare_for_compaction(&cp);
1255 scanning_gen = prev_gen(scanning_gen);
1256 }
1257 }
1258
1259 GCStats* GenCollectedHeap::gc_stats(int level) const {
1260 return _gens[level]->gc_stats();
1261 }
1262
1263 void GenCollectedHeap::verify(bool allow_dirty, bool silent, bool option /* ignored */) {
1264 if (!silent) {
1265 gclog_or_tty->print("permgen ");
1266 }
1267 perm_gen()->verify(allow_dirty);
1268 for (int i = _n_gens-1; i >= 0; i--) {
1269 Generation* g = _gens[i];
1270 if (!silent) {
1271 gclog_or_tty->print(g->name());
1272 gclog_or_tty->print(" ");
1273 }
1274 g->verify(allow_dirty);
1275 }
1276 if (!silent) {
1277 gclog_or_tty->print("remset ");
1278 }
1279 rem_set()->verify();
1280 if (!silent) {
1281 gclog_or_tty->print("ref_proc ");
1282 }
1283 ReferenceProcessor::verify();
1284 }
1285
1286 void GenCollectedHeap::print() const { print_on(tty); }
1287 void GenCollectedHeap::print_on(outputStream* st) const {
1288 for (int i = 0; i < _n_gens; i++) {
1289 _gens[i]->print_on(st);
1290 }
1291 perm_gen()->print_on(st);
1292 }
1293
1294 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1295 if (workers() != NULL) {
1296 workers()->threads_do(tc);
1297 }
1298 #ifndef SERIALGC
1299 if (UseConcMarkSweepGC) {
1300 ConcurrentMarkSweepThread::threads_do(tc);
1301 }
1302 #endif // SERIALGC
1303 }
1304
1305 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1306 #ifndef SERIALGC
1307 if (UseParNewGC) {
1308 workers()->print_worker_threads_on(st);
1309 }
1310 if (UseConcMarkSweepGC) {
1311 ConcurrentMarkSweepThread::print_all_on(st);
1312 }
1313 #endif // SERIALGC
1314 }
1315
1316 void GenCollectedHeap::print_tracing_info() const {
1317 if (TraceGen0Time) {
1318 get_gen(0)->print_summary_info();
1319 }
1320 if (TraceGen1Time) {
1321 get_gen(1)->print_summary_info();
1322 }
1323 }
1324
1325 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1326 if (PrintGCDetails && Verbose) {
1327 gclog_or_tty->print(" " SIZE_FORMAT
1328 "->" SIZE_FORMAT
1329 "(" SIZE_FORMAT ")",
1330 prev_used, used(), capacity());
1331 } else {
1332 gclog_or_tty->print(" " SIZE_FORMAT "K"
1333 "->" SIZE_FORMAT "K"
1334 "(" SIZE_FORMAT "K)",
1335 prev_used / K, used() / K, capacity() / K);
1336 }
1337 }
1338
1339 //New method to print perm gen info with PrintGCDetails flag
1340 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1341 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1342 perm_gen()->print_heap_change(perm_prev_used);
1343 gclog_or_tty->print("]");
1344 }
1345
1346 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1347 private:
1348 bool _full;
1349 public:
1350 void do_generation(Generation* gen) {
1351 gen->gc_prologue(_full);
1352 }
1353 GenGCPrologueClosure(bool full) : _full(full) {};
1354 };
1355
1356 void GenCollectedHeap::gc_prologue(bool full) {
1357 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1358
1359 always_do_update_barrier = false;
1360 // Fill TLAB's and such
1361 CollectedHeap::accumulate_statistics_all_tlabs();
1362 ensure_parsability(true); // retire TLABs
1363
1364 // Call allocation profiler
1365 AllocationProfiler::iterate_since_last_gc();
1366 // Walk generations
1367 GenGCPrologueClosure blk(full);
1368 generation_iterate(&blk, false); // not old-to-young.
1369 perm_gen()->gc_prologue(full);
1370 };
1371
1372 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1373 private:
1374 bool _full;
1375 public:
1376 void do_generation(Generation* gen) {
1377 gen->gc_epilogue(_full);
1378 }
1379 GenGCEpilogueClosure(bool full) : _full(full) {};
1380 };
1381
1382 void GenCollectedHeap::gc_epilogue(bool full) {
1383 // Remember if a partial collection of the heap failed, and
1384 // we did a complete collection.
1385 if (full && incremental_collection_will_fail()) {
1386 set_last_incremental_collection_failed();
1387 } else {
1388 clear_last_incremental_collection_failed();
1389 }
1390 // Clear the flag, if set; the generation gc_epilogues will set the
1391 // flag again if the condition persists despite the collection.
1392 clear_incremental_collection_will_fail();
1393
1394 #ifdef COMPILER2
1395 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1396 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1397 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1398 #endif /* COMPILER2 */
1399
1400 resize_all_tlabs();
1401
1402 GenGCEpilogueClosure blk(full);
1403 generation_iterate(&blk, false); // not old-to-young.
1404 perm_gen()->gc_epilogue(full);
1405
1406 always_do_update_barrier = UseConcMarkSweepGC;
1407 };
1408
1409 #ifndef PRODUCT
1410 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1411 private:
1412 public:
1413 void do_generation(Generation* gen) {
1414 gen->record_spaces_top();
1415 }
1416 };
1417
1418 void GenCollectedHeap::record_gen_tops_before_GC() {
1419 if (ZapUnusedHeapArea) {
1420 GenGCSaveTopsBeforeGCClosure blk;
1421 generation_iterate(&blk, false); // not old-to-young.
1422 perm_gen()->record_spaces_top();
1423 }
1424 }
1425 #endif // not PRODUCT
1426
1427 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1428 public:
1429 void do_generation(Generation* gen) {
1430 gen->ensure_parsability();
1431 }
1432 };
1433
1434 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1435 CollectedHeap::ensure_parsability(retire_tlabs);
1436 GenEnsureParsabilityClosure ep_cl;
1437 generation_iterate(&ep_cl, false);
1438 perm_gen()->ensure_parsability();
1439 }
1440
1441 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1442 oop obj,
1443 size_t obj_size) {
1444 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1445 HeapWord* result = NULL;
1446
1447 // First give each higher generation a chance to allocate the promoted object.
1448 Generation* allocator = next_gen(gen);
1449 if (allocator != NULL) {
1450 do {
1451 result = allocator->allocate(obj_size, false);
1452 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1453 }
1454
1455 if (result == NULL) {
1456 // Then give gen and higher generations a chance to expand and allocate the
1457 // object.
1458 do {
1459 result = gen->expand_and_allocate(obj_size, false);
1460 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1461 }
1462
1463 if (result != NULL) {
1464 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1465 }
1466 return oop(result);
1467 }
1468
1469 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1470 jlong _time; // in ms
1471 jlong _now; // in ms
1472
1473 public:
1474 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1475
1476 jlong time() { return _time; }
1477
1478 void do_generation(Generation* gen) {
1479 _time = MIN2(_time, gen->time_of_last_gc(_now));
1480 }
1481 };
1482
1483 jlong GenCollectedHeap::millis_since_last_gc() {
1484 jlong now = os::javaTimeMillis();
1485 GenTimeOfLastGCClosure tolgc_cl(now);
1486 // iterate over generations getting the oldest
1487 // time that a generation was collected
1488 generation_iterate(&tolgc_cl, false);
1489 tolgc_cl.do_generation(perm_gen());
1490 // XXX Despite the assert above, since javaTimeMillis()
1491 // doesnot guarantee monotonically increasing return
1492 // values (note, i didn't say "strictly monotonic"),
1493 // we need to guard against getting back a time
1494 // later than now. This should be fixed by basing
1495 // on someting like gethrtime() which guarantees
1496 // monotonicity. Note that cond_wait() is susceptible
1497 // to a similar problem, because its interface is
1498 // based on absolute time in the form of the
1499 // system time's notion of UCT. See also 4506635
1500 // for yet another problem of similar nature. XXX
1501 jlong retVal = now - tolgc_cl.time();
1502 if (retVal < 0) {
1503 NOT_PRODUCT(warning("time warp: %d", retVal);)
1504 return 0;
1505 }
1506 return retVal;
1507 }