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 "incls/_precompiled.incl"
26 # include "incls/_genCollectedHeap.cpp.incl"
27
28 GenCollectedHeap* GenCollectedHeap::_gch;
29 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
30
31 // The set of potentially parallel tasks in strong root scanning.
32 enum GCH_process_strong_roots_tasks {
33 // We probably want to parallelize both of these internally, but for now...
34 GCH_PS_younger_gens,
35 // Leave this one last.
36 GCH_PS_NumElements
37 };
38
39 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
40 SharedHeap(policy),
41 _gen_policy(policy),
42 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
43 _full_collections_completed(0)
44 {
45 if (_gen_process_strong_tasks == NULL ||
46 !_gen_process_strong_tasks->valid()) {
47 vm_exit_during_initialization("Failed necessary allocation.");
48 }
49 assert(policy != NULL, "Sanity check");
50 _preloading_shared_classes = false;
51 }
52
53 jint GenCollectedHeap::initialize() {
54 CollectedHeap::pre_initialize();
55
56 int i;
57 _n_gens = gen_policy()->number_of_generations();
58
59 // While there are no constraints in the GC code that HeapWordSize
60 // be any particular value, there are multiple other areas in the
61 // system which believe this to be true (e.g. oop->object_size in some
62 // cases incorrectly returns the size in wordSize units rather than
63 // HeapWordSize).
64 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
65
66 // The heap must be at least as aligned as generations.
67 size_t alignment = Generation::GenGrain;
68
69 _gen_specs = gen_policy()->generations();
70 PermanentGenerationSpec *perm_gen_spec =
71 collector_policy()->permanent_generation();
72
73 // Make sure the sizes are all aligned.
74 for (i = 0; i < _n_gens; i++) {
75 _gen_specs[i]->align(alignment);
76 }
77 perm_gen_spec->align(alignment);
78
79 // If we are dumping the heap, then allocate a wasted block of address
80 // space in order to push the heap to a lower address. This extra
81 // address range allows for other (or larger) libraries to be loaded
82 // without them occupying the space required for the shared spaces.
83
84 if (DumpSharedSpaces) {
85 uintx reserved = 0;
86 uintx block_size = 64*1024*1024;
87 while (reserved < SharedDummyBlockSize) {
88 char* dummy = os::reserve_memory(block_size);
89 reserved += block_size;
90 }
91 }
92
93 // Allocate space for the heap.
94
95 char* heap_address;
96 size_t total_reserved = 0;
97 int n_covered_regions = 0;
98 ReservedSpace heap_rs(0);
99
100 heap_address = allocate(alignment, perm_gen_spec, &total_reserved,
101 &n_covered_regions, &heap_rs);
102
103 if (UseSharedSpaces) {
104 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) {
105 if (heap_rs.is_reserved()) {
106 heap_rs.release();
107 }
108 FileMapInfo* mapinfo = FileMapInfo::current_info();
109 mapinfo->fail_continue("Unable to reserve shared region.");
110 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions,
111 &heap_rs);
112 }
113 }
114
115 if (!heap_rs.is_reserved()) {
116 vm_shutdown_during_initialization(
117 "Could not reserve enough space for object heap");
118 return JNI_ENOMEM;
119 }
120
121 _reserved = MemRegion((HeapWord*)heap_rs.base(),
122 (HeapWord*)(heap_rs.base() + heap_rs.size()));
123
124 // It is important to do this in a way such that concurrent readers can't
125 // temporarily think somethings in the heap. (Seen this happen in asserts.)
126 _reserved.set_word_size(0);
127 _reserved.set_start((HeapWord*)heap_rs.base());
128 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size()
129 - perm_gen_spec->misc_code_size();
130 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
131
132 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
133 set_barrier_set(rem_set()->bs());
134
135 _gch = this;
136
137 for (i = 0; i < _n_gens; i++) {
138 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(),
139 UseSharedSpaces, UseSharedSpaces);
140 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
141 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
142 }
143 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set());
144
145 clear_incremental_collection_will_fail();
146 clear_last_incremental_collection_failed();
147
148 #ifndef SERIALGC
149 // If we are running CMS, create the collector responsible
150 // for collecting the CMS generations.
151 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
152 bool success = create_cms_collector();
153 if (!success) return JNI_ENOMEM;
154 }
155 #endif // SERIALGC
156
157 return JNI_OK;
158 }
159
160
161 char* GenCollectedHeap::allocate(size_t alignment,
162 PermanentGenerationSpec* perm_gen_spec,
163 size_t* _total_reserved,
164 int* _n_covered_regions,
165 ReservedSpace* heap_rs){
166 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
167 "the maximum representable size";
168
169 // Now figure out the total size.
170 size_t total_reserved = 0;
171 int n_covered_regions = 0;
172 const size_t pageSize = UseLargePages ?
173 os::large_page_size() : os::vm_page_size();
174
175 for (int i = 0; i < _n_gens; i++) {
176 total_reserved += _gen_specs[i]->max_size();
177 if (total_reserved < _gen_specs[i]->max_size()) {
178 vm_exit_during_initialization(overflow_msg);
179 }
180 n_covered_regions += _gen_specs[i]->n_covered_regions();
181 }
182 assert(total_reserved % pageSize == 0,
183 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize="
184 SIZE_FORMAT, total_reserved, pageSize));
185 total_reserved += perm_gen_spec->max_size();
186 assert(total_reserved % pageSize == 0,
187 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize="
188 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved,
189 pageSize, perm_gen_spec->max_size()));
190
191 if (total_reserved < perm_gen_spec->max_size()) {
192 vm_exit_during_initialization(overflow_msg);
193 }
194 n_covered_regions += perm_gen_spec->n_covered_regions();
195
196 // Add the size of the data area which shares the same reserved area
197 // as the heap, but which is not actually part of the heap.
198 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
199
200 total_reserved += s;
201 if (total_reserved < s) {
202 vm_exit_during_initialization(overflow_msg);
203 }
204
205 if (UseLargePages) {
206 assert(total_reserved != 0, "total_reserved cannot be 0");
207 total_reserved = round_to(total_reserved, os::large_page_size());
208 if (total_reserved < os::large_page_size()) {
209 vm_exit_during_initialization(overflow_msg);
210 }
211 }
212
213 // Calculate the address at which the heap must reside in order for
214 // the shared data to be at the required address.
215
216 char* heap_address;
217 if (UseSharedSpaces) {
218
219 // Calculate the address of the first word beyond the heap.
220 FileMapInfo* mapinfo = FileMapInfo::current_info();
221 int lr = CompactingPermGenGen::n_regions - 1;
222 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
223 heap_address = mapinfo->region_base(lr) + capacity;
224
225 // Calculate the address of the first word of the heap.
226 heap_address -= total_reserved;
227 } else {
228 heap_address = NULL; // any address will do.
229 if (UseCompressedOops) {
230 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop);
231 *_total_reserved = total_reserved;
232 *_n_covered_regions = n_covered_regions;
233 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
234 UseLargePages, heap_address);
235
236 if (heap_address != NULL && !heap_rs->is_reserved()) {
237 // Failed to reserve at specified address - the requested memory
238 // region is taken already, for example, by 'java' launcher.
239 // Try again to reserver heap higher.
240 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop);
241 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
242 UseLargePages, heap_address);
243
244 if (heap_address != NULL && !heap_rs->is_reserved()) {
245 // Failed to reserve at specified address again - give up.
246 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop);
247 assert(heap_address == NULL, "");
248 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
249 UseLargePages, heap_address);
250 }
251 }
252 return heap_address;
253 }
254 }
255
256 *_total_reserved = total_reserved;
257 *_n_covered_regions = n_covered_regions;
258 *heap_rs = ReservedHeapSpace(total_reserved, alignment,
259 UseLargePages, heap_address);
260
261 return heap_address;
262 }
263
264
265 void GenCollectedHeap::post_initialize() {
266 SharedHeap::post_initialize();
267 TwoGenerationCollectorPolicy *policy =
268 (TwoGenerationCollectorPolicy *)collector_policy();
269 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
270 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
271 assert(def_new_gen->kind() == Generation::DefNew ||
272 def_new_gen->kind() == Generation::ParNew ||
273 def_new_gen->kind() == Generation::ASParNew,
274 "Wrong generation kind");
275
276 Generation* old_gen = get_gen(1);
277 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
278 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
279 old_gen->kind() == Generation::MarkSweepCompact,
280 "Wrong generation kind");
281
282 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
283 old_gen->capacity(),
284 def_new_gen->from()->capacity());
285 policy->initialize_gc_policy_counters();
286 }
287
288 void GenCollectedHeap::ref_processing_init() {
289 SharedHeap::ref_processing_init();
290 for (int i = 0; i < _n_gens; i++) {
291 _gens[i]->ref_processor_init();
292 }
293 }
294
295 size_t GenCollectedHeap::capacity() const {
296 size_t res = 0;
297 for (int i = 0; i < _n_gens; i++) {
298 res += _gens[i]->capacity();
299 }
300 return res;
301 }
302
303 size_t GenCollectedHeap::used() const {
304 size_t res = 0;
305 for (int i = 0; i < _n_gens; i++) {
306 res += _gens[i]->used();
307 }
308 return res;
309 }
310
311 // Save the "used_region" for generations level and lower,
312 // and, if perm is true, for perm gen.
313 void GenCollectedHeap::save_used_regions(int level, bool perm) {
314 assert(level < _n_gens, "Illegal level parameter");
315 for (int i = level; i >= 0; i--) {
316 _gens[i]->save_used_region();
317 }
318 if (perm) {
319 perm_gen()->save_used_region();
320 }
321 }
322
323 size_t GenCollectedHeap::max_capacity() const {
324 size_t res = 0;
325 for (int i = 0; i < _n_gens; i++) {
326 res += _gens[i]->max_capacity();
327 }
328 return res;
329 }
330
331 // Update the _full_collections_completed counter
332 // at the end of a stop-world full GC.
333 unsigned int GenCollectedHeap::update_full_collections_completed() {
334 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
335 assert(_full_collections_completed <= _total_full_collections,
336 "Can't complete more collections than were started");
337 _full_collections_completed = _total_full_collections;
338 ml.notify_all();
339 return _full_collections_completed;
340 }
341
342 // Update the _full_collections_completed counter, as appropriate,
343 // at the end of a concurrent GC cycle. Note the conditional update
344 // below to allow this method to be called by a concurrent collector
345 // without synchronizing in any manner with the VM thread (which
346 // may already have initiated a STW full collection "concurrently").
347 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
348 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
349 assert((_full_collections_completed <= _total_full_collections) &&
350 (count <= _total_full_collections),
351 "Can't complete more collections than were started");
352 if (count > _full_collections_completed) {
353 _full_collections_completed = count;
354 ml.notify_all();
355 }
356 return _full_collections_completed;
357 }
358
359
360 #ifndef PRODUCT
361 // Override of memory state checking method in CollectedHeap:
362 // Some collectors (CMS for example) can't have badHeapWordVal written
363 // in the first two words of an object. (For instance , in the case of
364 // CMS these words hold state used to synchronize between certain
365 // (concurrent) GC steps and direct allocating mutators.)
366 // The skip_header_HeapWords() method below, allows us to skip
367 // over the requisite number of HeapWord's. Note that (for
368 // generational collectors) this means that those many words are
369 // skipped in each object, irrespective of the generation in which
370 // that object lives. The resultant loss of precision seems to be
371 // harmless and the pain of avoiding that imprecision appears somewhat
372 // higher than we are prepared to pay for such rudimentary debugging
373 // support.
374 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
375 size_t size) {
376 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
377 // We are asked to check a size in HeapWords,
378 // but the memory is mangled in juint words.
379 juint* start = (juint*) (addr + skip_header_HeapWords());
380 juint* end = (juint*) (addr + size);
381 for (juint* slot = start; slot < end; slot += 1) {
382 assert(*slot == badHeapWordVal,
383 "Found non badHeapWordValue in pre-allocation check");
384 }
385 }
386 }
387 #endif
388
389 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
390 bool is_tlab,
391 bool first_only) {
392 HeapWord* res;
393 for (int i = 0; i < _n_gens; i++) {
394 if (_gens[i]->should_allocate(size, is_tlab)) {
395 res = _gens[i]->allocate(size, is_tlab);
396 if (res != NULL) return res;
397 else if (first_only) break;
398 }
399 }
400 // Otherwise...
401 return NULL;
402 }
403
404 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
405 bool is_large_noref,
406 bool is_tlab,
407 bool* gc_overhead_limit_was_exceeded) {
408 return collector_policy()->mem_allocate_work(size,
409 is_tlab,
410 gc_overhead_limit_was_exceeded);
411 }
412
413 bool GenCollectedHeap::must_clear_all_soft_refs() {
414 return _gc_cause == GCCause::_last_ditch_collection;
415 }
416
417 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
418 return UseConcMarkSweepGC &&
419 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
420 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent));
421 }
422
423 void GenCollectedHeap::do_collection(bool full,
424 bool clear_all_soft_refs,
425 size_t size,
426 bool is_tlab,
427 int max_level) {
428 bool prepared_for_verification = false;
429 ResourceMark rm;
430 DEBUG_ONLY(Thread* my_thread = Thread::current();)
431
432 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
433 assert(my_thread->is_VM_thread() ||
434 my_thread->is_ConcurrentGC_thread(),
435 "incorrect thread type capability");
436 assert(Heap_lock->is_locked(),
437 "the requesting thread should have the Heap_lock");
438 guarantee(!is_gc_active(), "collection is not reentrant");
439 assert(max_level < n_gens(), "sanity check");
440
441 if (GC_locker::check_active_before_gc()) {
442 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
443 }
444
445 const bool do_clear_all_soft_refs = clear_all_soft_refs ||
446 collector_policy()->should_clear_all_soft_refs();
447
448 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
449
450 const size_t perm_prev_used = perm_gen()->used();
451
452 if (PrintHeapAtGC) {
453 Universe::print_heap_before_gc();
454 if (Verbose) {
455 gclog_or_tty->print_cr("GC Cause: %s", GCCause::to_string(gc_cause()));
456 }
457 }
458
459 {
460 FlagSetting fl(_is_gc_active, true);
461
462 bool complete = full && (max_level == (n_gens()-1));
463 const char* gc_cause_str = "GC ";
464 if (complete) {
465 GCCause::Cause cause = gc_cause();
466 if (cause == GCCause::_java_lang_system_gc) {
467 gc_cause_str = "Full GC (System) ";
468 } else {
469 gc_cause_str = "Full GC ";
470 }
471 }
472 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
473 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
474 TraceTime t(gc_cause_str, PrintGCDetails, false, gclog_or_tty);
475
476 gc_prologue(complete);
477 increment_total_collections(complete);
478
479 size_t gch_prev_used = used();
480
481 int starting_level = 0;
482 if (full) {
483 // Search for the oldest generation which will collect all younger
484 // generations, and start collection loop there.
485 for (int i = max_level; i >= 0; i--) {
486 if (_gens[i]->full_collects_younger_generations()) {
487 starting_level = i;
488 break;
489 }
490 }
491 }
492
493 bool must_restore_marks_for_biased_locking = false;
494
495 int max_level_collected = starting_level;
496 for (int i = starting_level; i <= max_level; i++) {
497 if (_gens[i]->should_collect(full, size, is_tlab)) {
498 if (i == n_gens() - 1) { // a major collection is to happen
499 if (!complete) {
500 // The full_collections increment was missed above.
501 increment_total_full_collections();
502 }
503 pre_full_gc_dump(); // do any pre full gc dumps
504 }
505 // Timer for individual generations. Last argument is false: no CR
506 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty);
507 TraceCollectorStats tcs(_gens[i]->counters());
508 TraceMemoryManagerStats tmms(_gens[i]->kind());
509
510 size_t prev_used = _gens[i]->used();
511 _gens[i]->stat_record()->invocations++;
512 _gens[i]->stat_record()->accumulated_time.start();
513
514 // Must be done anew before each collection because
515 // a previous collection will do mangling and will
516 // change top of some spaces.
517 record_gen_tops_before_GC();
518
519 if (PrintGC && Verbose) {
520 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
521 i,
522 _gens[i]->stat_record()->invocations,
523 size*HeapWordSize);
524 }
525
526 if (VerifyBeforeGC && i >= VerifyGCLevel &&
527 total_collections() >= VerifyGCStartAt) {
528 HandleMark hm; // Discard invalid handles created during verification
529 if (!prepared_for_verification) {
530 prepare_for_verify();
531 prepared_for_verification = true;
532 }
533 gclog_or_tty->print(" VerifyBeforeGC:");
534 Universe::verify(true);
535 }
536 COMPILER2_PRESENT(DerivedPointerTable::clear());
537
538 if (!must_restore_marks_for_biased_locking &&
539 _gens[i]->performs_in_place_marking()) {
540 // We perform this mark word preservation work lazily
541 // because it's only at this point that we know whether we
542 // absolutely have to do it; we want to avoid doing it for
543 // scavenge-only collections where it's unnecessary
544 must_restore_marks_for_biased_locking = true;
545 BiasedLocking::preserve_marks();
546 }
547
548 // Do collection work
549 {
550 // Note on ref discovery: For what appear to be historical reasons,
551 // GCH enables and disabled (by enqueing) refs discovery.
552 // In the future this should be moved into the generation's
553 // collect method so that ref discovery and enqueueing concerns
554 // are local to a generation. The collect method could return
555 // an appropriate indication in the case that notification on
556 // the ref lock was needed. This will make the treatment of
557 // weak refs more uniform (and indeed remove such concerns
558 // from GCH). XXX
559
560 HandleMark hm; // Discard invalid handles created during gc
561 save_marks(); // save marks for all gens
562 // We want to discover references, but not process them yet.
563 // This mode is disabled in process_discovered_references if the
564 // generation does some collection work, or in
565 // enqueue_discovered_references if the generation returns
566 // without doing any work.
567 ReferenceProcessor* rp = _gens[i]->ref_processor();
568 // If the discovery of ("weak") refs in this generation is
569 // atomic wrt other collectors in this configuration, we
570 // are guaranteed to have empty discovered ref lists.
571 if (rp->discovery_is_atomic()) {
572 rp->verify_no_references_recorded();
573 rp->enable_discovery();
574 rp->setup_policy(do_clear_all_soft_refs);
575 } else {
576 // collect() below will enable discovery as appropriate
577 }
578 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab);
579 if (!rp->enqueuing_is_done()) {
580 rp->enqueue_discovered_references();
581 } else {
582 rp->set_enqueuing_is_done(false);
583 }
584 rp->verify_no_references_recorded();
585 }
586 max_level_collected = i;
587
588 // Determine if allocation request was met.
589 if (size > 0) {
590 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
591 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
592 size = 0;
593 }
594 }
595 }
596
597 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
598
599 _gens[i]->stat_record()->accumulated_time.stop();
600
601 update_gc_stats(i, full);
602
603 if (VerifyAfterGC && i >= VerifyGCLevel &&
604 total_collections() >= VerifyGCStartAt) {
605 HandleMark hm; // Discard invalid handles created during verification
606 gclog_or_tty->print(" VerifyAfterGC:");
607 Universe::verify(false);
608 }
609
610 if (PrintGCDetails) {
611 gclog_or_tty->print(":");
612 _gens[i]->print_heap_change(prev_used);
613 }
614 }
615 }
616
617 // Update "complete" boolean wrt what actually transpired --
618 // for instance, a promotion failure could have led to
619 // a whole heap collection.
620 complete = complete || (max_level_collected == n_gens() - 1);
621
622 if (complete) { // We did a "major" collection
623 post_full_gc_dump(); // do any post full gc dumps
624 }
625
626 if (PrintGCDetails) {
627 print_heap_change(gch_prev_used);
628
629 // Print perm gen info for full GC with PrintGCDetails flag.
630 if (complete) {
631 print_perm_heap_change(perm_prev_used);
632 }
633 }
634
635 for (int j = max_level_collected; j >= 0; j -= 1) {
636 // Adjust generation sizes.
637 _gens[j]->compute_new_size();
638 }
639
640 if (complete) {
641 // Ask the permanent generation to adjust size for full collections
642 perm()->compute_new_size();
643 update_full_collections_completed();
644 }
645
646 // Track memory usage and detect low memory after GC finishes
647 MemoryService::track_memory_usage();
648
649 gc_epilogue(complete);
650
651 if (must_restore_marks_for_biased_locking) {
652 BiasedLocking::restore_marks();
653 }
654 }
655
656 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
657 AdaptiveSizePolicyOutput(sp, total_collections());
658
659 if (PrintHeapAtGC) {
660 Universe::print_heap_after_gc();
661 }
662
663 #ifdef TRACESPINNING
664 ParallelTaskTerminator::print_termination_counts();
665 #endif
666
667 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) {
668 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum);
669 vm_exit(-1);
670 }
671 }
672
673 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
674 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
675 }
676
677 void GenCollectedHeap::set_par_threads(int t) {
678 SharedHeap::set_par_threads(t);
679 _gen_process_strong_tasks->set_n_threads(t);
680 }
681
682 class AssertIsPermClosure: public OopClosure {
683 public:
684 void do_oop(oop* p) {
685 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
686 }
687 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
688 };
689 static AssertIsPermClosure assert_is_perm_closure;
690
691 void GenCollectedHeap::
692 gen_process_strong_roots(int level,
693 bool younger_gens_as_roots,
694 bool activate_scope,
695 bool collecting_perm_gen,
696 SharedHeap::ScanningOption so,
697 OopsInGenClosure* not_older_gens,
698 bool do_code_roots,
699 OopsInGenClosure* older_gens) {
700 // General strong roots.
701
702 if (!do_code_roots) {
703 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
704 not_older_gens, NULL, older_gens);
705 } else {
706 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active());
707 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking);
708 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so,
709 not_older_gens, &code_roots, older_gens);
710 }
711
712 if (younger_gens_as_roots) {
713 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
714 for (int i = 0; i < level; i++) {
715 not_older_gens->set_generation(_gens[i]);
716 _gens[i]->oop_iterate(not_older_gens);
717 }
718 not_older_gens->reset_generation();
719 }
720 }
721 // When collection is parallel, all threads get to cooperate to do
722 // older-gen scanning.
723 for (int i = level+1; i < _n_gens; i++) {
724 older_gens->set_generation(_gens[i]);
725 rem_set()->younger_refs_iterate(_gens[i], older_gens);
726 older_gens->reset_generation();
727 }
728
729 _gen_process_strong_tasks->all_tasks_completed();
730 }
731
732 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
733 CodeBlobClosure* code_roots,
734 OopClosure* non_root_closure) {
735 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure);
736 // "Local" "weak" refs
737 for (int i = 0; i < _n_gens; i++) {
738 _gens[i]->ref_processor()->weak_oops_do(root_closure);
739 }
740 }
741
742 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
743 void GenCollectedHeap:: \
744 oop_since_save_marks_iterate(int level, \
745 OopClosureType* cur, \
746 OopClosureType* older) { \
747 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
748 for (int i = level+1; i < n_gens(); i++) { \
749 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
750 } \
751 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
752 }
753
754 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
755
756 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
757
758 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
759 for (int i = level; i < _n_gens; i++) {
760 if (!_gens[i]->no_allocs_since_save_marks()) return false;
761 }
762 return perm_gen()->no_allocs_since_save_marks();
763 }
764
765 bool GenCollectedHeap::supports_inline_contig_alloc() const {
766 return _gens[0]->supports_inline_contig_alloc();
767 }
768
769 HeapWord** GenCollectedHeap::top_addr() const {
770 return _gens[0]->top_addr();
771 }
772
773 HeapWord** GenCollectedHeap::end_addr() const {
774 return _gens[0]->end_addr();
775 }
776
777 size_t GenCollectedHeap::unsafe_max_alloc() {
778 return _gens[0]->unsafe_max_alloc_nogc();
779 }
780
781 // public collection interfaces
782
783 void GenCollectedHeap::collect(GCCause::Cause cause) {
784 if (should_do_concurrent_full_gc(cause)) {
785 #ifndef SERIALGC
786 // mostly concurrent full collection
787 collect_mostly_concurrent(cause);
788 #else // SERIALGC
789 ShouldNotReachHere();
790 #endif // SERIALGC
791 } else {
792 #ifdef ASSERT
793 if (cause == GCCause::_scavenge_alot) {
794 // minor collection only
795 collect(cause, 0);
796 } else {
797 // Stop-the-world full collection
798 collect(cause, n_gens() - 1);
799 }
800 #else
801 // Stop-the-world full collection
802 collect(cause, n_gens() - 1);
803 #endif
804 }
805 }
806
807 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
808 // The caller doesn't have the Heap_lock
809 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
810 MutexLocker ml(Heap_lock);
811 collect_locked(cause, max_level);
812 }
813
814 // This interface assumes that it's being called by the
815 // vm thread. It collects the heap assuming that the
816 // heap lock is already held and that we are executing in
817 // the context of the vm thread.
818 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
819 assert(Thread::current()->is_VM_thread(), "Precondition#1");
820 assert(Heap_lock->is_locked(), "Precondition#2");
821 GCCauseSetter gcs(this, cause);
822 switch (cause) {
823 case GCCause::_heap_inspection:
824 case GCCause::_heap_dump: {
825 HandleMark hm;
826 do_full_collection(false, // don't clear all soft refs
827 n_gens() - 1);
828 break;
829 }
830 default: // XXX FIX ME
831 ShouldNotReachHere(); // Unexpected use of this function
832 }
833 }
834
835 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
836 // The caller has the Heap_lock
837 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
838 collect_locked(cause, n_gens() - 1);
839 }
840
841 // this is the private collection interface
842 // The Heap_lock is expected to be held on entry.
843
844 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
845 if (_preloading_shared_classes) {
846 warning("\nThe permanent generation is not large enough to preload "
847 "requested classes.\nUse -XX:PermSize= to increase the initial "
848 "size of the permanent generation.\n");
849 vm_exit(2);
850 }
851 // Read the GC count while holding the Heap_lock
852 unsigned int gc_count_before = total_collections();
853 unsigned int full_gc_count_before = total_full_collections();
854 {
855 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
856 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
857 cause, max_level);
858 VMThread::execute(&op);
859 }
860 }
861
862 #ifndef SERIALGC
863 bool GenCollectedHeap::create_cms_collector() {
864
865 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
866 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
867 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
868 "Unexpected generation kinds");
869 // Skip two header words in the block content verification
870 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
871 CMSCollector* collector = new CMSCollector(
872 (ConcurrentMarkSweepGeneration*)_gens[1],
873 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
874 _rem_set->as_CardTableRS(),
875 (ConcurrentMarkSweepPolicy*) collector_policy());
876
877 if (collector == NULL || !collector->completed_initialization()) {
878 if (collector) {
879 delete collector; // Be nice in embedded situation
880 }
881 vm_shutdown_during_initialization("Could not create CMS collector");
882 return false;
883 }
884 return true; // success
885 }
886
887 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
888 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
889
890 MutexLocker ml(Heap_lock);
891 // Read the GC counts while holding the Heap_lock
892 unsigned int full_gc_count_before = total_full_collections();
893 unsigned int gc_count_before = total_collections();
894 {
895 MutexUnlocker mu(Heap_lock);
896 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
897 VMThread::execute(&op);
898 }
899 }
900 #endif // SERIALGC
901
902
903 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
904 int max_level) {
905 int local_max_level;
906 if (!incremental_collection_will_fail() &&
907 gc_cause() == GCCause::_gc_locker) {
908 local_max_level = 0;
909 } else {
910 local_max_level = max_level;
911 }
912
913 do_collection(true /* full */,
914 clear_all_soft_refs /* clear_all_soft_refs */,
915 0 /* size */,
916 false /* is_tlab */,
917 local_max_level /* max_level */);
918 // Hack XXX FIX ME !!!
919 // A scavenge may not have been attempted, or may have
920 // been attempted and failed, because the old gen was too full
921 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
922 incremental_collection_will_fail()) {
923 if (PrintGCDetails) {
924 gclog_or_tty->print_cr("GC locker: Trying a full collection "
925 "because scavenge failed");
926 }
927 // This time allow the old gen to be collected as well
928 do_collection(true /* full */,
929 clear_all_soft_refs /* clear_all_soft_refs */,
930 0 /* size */,
931 false /* is_tlab */,
932 n_gens() - 1 /* max_level */);
933 }
934 }
935
936 // Returns "TRUE" iff "p" points into the allocated area of the heap.
937 bool GenCollectedHeap::is_in(const void* p) const {
938 #ifndef ASSERT
939 guarantee(VerifyBeforeGC ||
940 VerifyDuringGC ||
941 VerifyBeforeExit ||
942 PrintAssembly ||
943 tty->count() != 0 || // already printing
944 VerifyAfterGC ||
945 VMError::fatal_error_in_progress(), "too expensive");
946
947 #endif
948 // This might be sped up with a cache of the last generation that
949 // answered yes.
950 for (int i = 0; i < _n_gens; i++) {
951 if (_gens[i]->is_in(p)) return true;
952 }
953 if (_perm_gen->as_gen()->is_in(p)) return true;
954 // Otherwise...
955 return false;
956 }
957
958 // Returns "TRUE" iff "p" points into the allocated area of the heap.
959 bool GenCollectedHeap::is_in_youngest(void* p) {
960 return _gens[0]->is_in(p);
961 }
962
963 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
964 for (int i = 0; i < _n_gens; i++) {
965 _gens[i]->oop_iterate(cl);
966 }
967 }
968
969 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
970 for (int i = 0; i < _n_gens; i++) {
971 _gens[i]->oop_iterate(mr, cl);
972 }
973 }
974
975 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
976 for (int i = 0; i < _n_gens; i++) {
977 _gens[i]->object_iterate(cl);
978 }
979 perm_gen()->object_iterate(cl);
980 }
981
982 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
983 for (int i = 0; i < _n_gens; i++) {
984 _gens[i]->safe_object_iterate(cl);
985 }
986 perm_gen()->safe_object_iterate(cl);
987 }
988
989 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
990 for (int i = 0; i < _n_gens; i++) {
991 _gens[i]->object_iterate_since_last_GC(cl);
992 }
993 }
994
995 Space* GenCollectedHeap::space_containing(const void* addr) const {
996 for (int i = 0; i < _n_gens; i++) {
997 Space* res = _gens[i]->space_containing(addr);
998 if (res != NULL) return res;
999 }
1000 Space* res = perm_gen()->space_containing(addr);
1001 if (res != NULL) return res;
1002 // Otherwise...
1003 assert(false, "Could not find containing space");
1004 return NULL;
1005 }
1006
1007
1008 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
1009 assert(is_in_reserved(addr), "block_start of address outside of heap");
1010 for (int i = 0; i < _n_gens; i++) {
1011 if (_gens[i]->is_in_reserved(addr)) {
1012 assert(_gens[i]->is_in(addr),
1013 "addr should be in allocated part of generation");
1014 return _gens[i]->block_start(addr);
1015 }
1016 }
1017 if (perm_gen()->is_in_reserved(addr)) {
1018 assert(perm_gen()->is_in(addr),
1019 "addr should be in allocated part of perm gen");
1020 return perm_gen()->block_start(addr);
1021 }
1022 assert(false, "Some generation should contain the address");
1023 return NULL;
1024 }
1025
1026 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
1027 assert(is_in_reserved(addr), "block_size of address outside of heap");
1028 for (int i = 0; i < _n_gens; i++) {
1029 if (_gens[i]->is_in_reserved(addr)) {
1030 assert(_gens[i]->is_in(addr),
1031 "addr should be in allocated part of generation");
1032 return _gens[i]->block_size(addr);
1033 }
1034 }
1035 if (perm_gen()->is_in_reserved(addr)) {
1036 assert(perm_gen()->is_in(addr),
1037 "addr should be in allocated part of perm gen");
1038 return perm_gen()->block_size(addr);
1039 }
1040 assert(false, "Some generation should contain the address");
1041 return 0;
1042 }
1043
1044 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
1045 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
1046 assert(block_start(addr) == addr, "addr must be a block start");
1047 for (int i = 0; i < _n_gens; i++) {
1048 if (_gens[i]->is_in_reserved(addr)) {
1049 return _gens[i]->block_is_obj(addr);
1050 }
1051 }
1052 if (perm_gen()->is_in_reserved(addr)) {
1053 return perm_gen()->block_is_obj(addr);
1054 }
1055 assert(false, "Some generation should contain the address");
1056 return false;
1057 }
1058
1059 bool GenCollectedHeap::supports_tlab_allocation() const {
1060 for (int i = 0; i < _n_gens; i += 1) {
1061 if (_gens[i]->supports_tlab_allocation()) {
1062 return true;
1063 }
1064 }
1065 return false;
1066 }
1067
1068 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
1069 size_t result = 0;
1070 for (int i = 0; i < _n_gens; i += 1) {
1071 if (_gens[i]->supports_tlab_allocation()) {
1072 result += _gens[i]->tlab_capacity();
1073 }
1074 }
1075 return result;
1076 }
1077
1078 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
1079 size_t result = 0;
1080 for (int i = 0; i < _n_gens; i += 1) {
1081 if (_gens[i]->supports_tlab_allocation()) {
1082 result += _gens[i]->unsafe_max_tlab_alloc();
1083 }
1084 }
1085 return result;
1086 }
1087
1088 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
1089 bool gc_overhead_limit_was_exceeded;
1090 HeapWord* result = mem_allocate(size /* size */,
1091 false /* is_large_noref */,
1092 true /* is_tlab */,
1093 &gc_overhead_limit_was_exceeded);
1094 return result;
1095 }
1096
1097 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
1098 // from the list headed by "*prev_ptr".
1099 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
1100 bool first = true;
1101 size_t min_size = 0; // "first" makes this conceptually infinite.
1102 ScratchBlock **smallest_ptr, *smallest;
1103 ScratchBlock *cur = *prev_ptr;
1104 while (cur) {
1105 assert(*prev_ptr == cur, "just checking");
1106 if (first || cur->num_words < min_size) {
1107 smallest_ptr = prev_ptr;
1108 smallest = cur;
1109 min_size = smallest->num_words;
1110 first = false;
1111 }
1112 prev_ptr = &cur->next;
1113 cur = cur->next;
1114 }
1115 smallest = *smallest_ptr;
1116 *smallest_ptr = smallest->next;
1117 return smallest;
1118 }
1119
1120 // Sort the scratch block list headed by res into decreasing size order,
1121 // and set "res" to the result.
1122 static void sort_scratch_list(ScratchBlock*& list) {
1123 ScratchBlock* sorted = NULL;
1124 ScratchBlock* unsorted = list;
1125 while (unsorted) {
1126 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
1127 smallest->next = sorted;
1128 sorted = smallest;
1129 }
1130 list = sorted;
1131 }
1132
1133 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
1134 size_t max_alloc_words) {
1135 ScratchBlock* res = NULL;
1136 for (int i = 0; i < _n_gens; i++) {
1137 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
1138 }
1139 sort_scratch_list(res);
1140 return res;
1141 }
1142
1143 void GenCollectedHeap::release_scratch() {
1144 for (int i = 0; i < _n_gens; i++) {
1145 _gens[i]->reset_scratch();
1146 }
1147 }
1148
1149 size_t GenCollectedHeap::large_typearray_limit() {
1150 return gen_policy()->large_typearray_limit();
1151 }
1152
1153 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
1154 void do_generation(Generation* gen) {
1155 gen->prepare_for_verify();
1156 }
1157 };
1158
1159 void GenCollectedHeap::prepare_for_verify() {
1160 ensure_parsability(false); // no need to retire TLABs
1161 GenPrepareForVerifyClosure blk;
1162 generation_iterate(&blk, false);
1163 perm_gen()->prepare_for_verify();
1164 }
1165
1166
1167 void GenCollectedHeap::generation_iterate(GenClosure* cl,
1168 bool old_to_young) {
1169 if (old_to_young) {
1170 for (int i = _n_gens-1; i >= 0; i--) {
1171 cl->do_generation(_gens[i]);
1172 }
1173 } else {
1174 for (int i = 0; i < _n_gens; i++) {
1175 cl->do_generation(_gens[i]);
1176 }
1177 }
1178 }
1179
1180 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
1181 for (int i = 0; i < _n_gens; i++) {
1182 _gens[i]->space_iterate(cl, true);
1183 }
1184 perm_gen()->space_iterate(cl, true);
1185 }
1186
1187 bool GenCollectedHeap::is_maximal_no_gc() const {
1188 for (int i = 0; i < _n_gens; i++) { // skip perm gen
1189 if (!_gens[i]->is_maximal_no_gc()) {
1190 return false;
1191 }
1192 }
1193 return true;
1194 }
1195
1196 void GenCollectedHeap::save_marks() {
1197 for (int i = 0; i < _n_gens; i++) {
1198 _gens[i]->save_marks();
1199 }
1200 perm_gen()->save_marks();
1201 }
1202
1203 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
1204 for (int i = 0; i <= collectedGen; i++) {
1205 _gens[i]->compute_new_size();
1206 }
1207 }
1208
1209 GenCollectedHeap* GenCollectedHeap::heap() {
1210 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
1211 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
1212 return _gch;
1213 }
1214
1215
1216 void GenCollectedHeap::prepare_for_compaction() {
1217 Generation* scanning_gen = _gens[_n_gens-1];
1218 // Start by compacting into same gen.
1219 CompactPoint cp(scanning_gen, NULL, NULL);
1220 while (scanning_gen != NULL) {
1221 scanning_gen->prepare_for_compaction(&cp);
1222 scanning_gen = prev_gen(scanning_gen);
1223 }
1224 }
1225
1226 GCStats* GenCollectedHeap::gc_stats(int level) const {
1227 return _gens[level]->gc_stats();
1228 }
1229
1230 void GenCollectedHeap::verify(bool allow_dirty, bool silent, bool option /* ignored */) {
1231 if (!silent) {
1232 gclog_or_tty->print("permgen ");
1233 }
1234 perm_gen()->verify(allow_dirty);
1235 for (int i = _n_gens-1; i >= 0; i--) {
1236 Generation* g = _gens[i];
1237 if (!silent) {
1238 gclog_or_tty->print(g->name());
1239 gclog_or_tty->print(" ");
1240 }
1241 g->verify(allow_dirty);
1242 }
1243 if (!silent) {
1244 gclog_or_tty->print("remset ");
1245 }
1246 rem_set()->verify();
1247 if (!silent) {
1248 gclog_or_tty->print("ref_proc ");
1249 }
1250 ReferenceProcessor::verify();
1251 }
1252
1253 void GenCollectedHeap::print() const { print_on(tty); }
1254 void GenCollectedHeap::print_on(outputStream* st) const {
1255 for (int i = 0; i < _n_gens; i++) {
1256 _gens[i]->print_on(st);
1257 }
1258 perm_gen()->print_on(st);
1259 }
1260
1261 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
1262 if (workers() != NULL) {
1263 workers()->threads_do(tc);
1264 }
1265 #ifndef SERIALGC
1266 if (UseConcMarkSweepGC) {
1267 ConcurrentMarkSweepThread::threads_do(tc);
1268 }
1269 #endif // SERIALGC
1270 }
1271
1272 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
1273 #ifndef SERIALGC
1274 if (UseParNewGC) {
1275 workers()->print_worker_threads_on(st);
1276 }
1277 if (UseConcMarkSweepGC) {
1278 ConcurrentMarkSweepThread::print_all_on(st);
1279 }
1280 #endif // SERIALGC
1281 }
1282
1283 void GenCollectedHeap::print_tracing_info() const {
1284 if (TraceGen0Time) {
1285 get_gen(0)->print_summary_info();
1286 }
1287 if (TraceGen1Time) {
1288 get_gen(1)->print_summary_info();
1289 }
1290 }
1291
1292 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
1293 if (PrintGCDetails && Verbose) {
1294 gclog_or_tty->print(" " SIZE_FORMAT
1295 "->" SIZE_FORMAT
1296 "(" SIZE_FORMAT ")",
1297 prev_used, used(), capacity());
1298 } else {
1299 gclog_or_tty->print(" " SIZE_FORMAT "K"
1300 "->" SIZE_FORMAT "K"
1301 "(" SIZE_FORMAT "K)",
1302 prev_used / K, used() / K, capacity() / K);
1303 }
1304 }
1305
1306 //New method to print perm gen info with PrintGCDetails flag
1307 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
1308 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
1309 perm_gen()->print_heap_change(perm_prev_used);
1310 gclog_or_tty->print("]");
1311 }
1312
1313 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
1314 private:
1315 bool _full;
1316 public:
1317 void do_generation(Generation* gen) {
1318 gen->gc_prologue(_full);
1319 }
1320 GenGCPrologueClosure(bool full) : _full(full) {};
1321 };
1322
1323 void GenCollectedHeap::gc_prologue(bool full) {
1324 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
1325
1326 always_do_update_barrier = false;
1327 // Fill TLAB's and such
1328 CollectedHeap::accumulate_statistics_all_tlabs();
1329 ensure_parsability(true); // retire TLABs
1330
1331 // Call allocation profiler
1332 AllocationProfiler::iterate_since_last_gc();
1333 // Walk generations
1334 GenGCPrologueClosure blk(full);
1335 generation_iterate(&blk, false); // not old-to-young.
1336 perm_gen()->gc_prologue(full);
1337 };
1338
1339 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
1340 private:
1341 bool _full;
1342 public:
1343 void do_generation(Generation* gen) {
1344 gen->gc_epilogue(_full);
1345 }
1346 GenGCEpilogueClosure(bool full) : _full(full) {};
1347 };
1348
1349 void GenCollectedHeap::gc_epilogue(bool full) {
1350 // Remember if a partial collection of the heap failed, and
1351 // we did a complete collection.
1352 if (full && incremental_collection_will_fail()) {
1353 set_last_incremental_collection_failed();
1354 } else {
1355 clear_last_incremental_collection_failed();
1356 }
1357 // Clear the flag, if set; the generation gc_epilogues will set the
1358 // flag again if the condition persists despite the collection.
1359 clear_incremental_collection_will_fail();
1360
1361 #ifdef COMPILER2
1362 assert(DerivedPointerTable::is_empty(), "derived pointer present");
1363 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
1364 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
1365 #endif /* COMPILER2 */
1366
1367 resize_all_tlabs();
1368
1369 GenGCEpilogueClosure blk(full);
1370 generation_iterate(&blk, false); // not old-to-young.
1371 perm_gen()->gc_epilogue(full);
1372
1373 always_do_update_barrier = UseConcMarkSweepGC;
1374 };
1375
1376 #ifndef PRODUCT
1377 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure {
1378 private:
1379 public:
1380 void do_generation(Generation* gen) {
1381 gen->record_spaces_top();
1382 }
1383 };
1384
1385 void GenCollectedHeap::record_gen_tops_before_GC() {
1386 if (ZapUnusedHeapArea) {
1387 GenGCSaveTopsBeforeGCClosure blk;
1388 generation_iterate(&blk, false); // not old-to-young.
1389 perm_gen()->record_spaces_top();
1390 }
1391 }
1392 #endif // not PRODUCT
1393
1394 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
1395 public:
1396 void do_generation(Generation* gen) {
1397 gen->ensure_parsability();
1398 }
1399 };
1400
1401 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
1402 CollectedHeap::ensure_parsability(retire_tlabs);
1403 GenEnsureParsabilityClosure ep_cl;
1404 generation_iterate(&ep_cl, false);
1405 perm_gen()->ensure_parsability();
1406 }
1407
1408 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
1409 oop obj,
1410 size_t obj_size) {
1411 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
1412 HeapWord* result = NULL;
1413
1414 // First give each higher generation a chance to allocate the promoted object.
1415 Generation* allocator = next_gen(gen);
1416 if (allocator != NULL) {
1417 do {
1418 result = allocator->allocate(obj_size, false);
1419 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
1420 }
1421
1422 if (result == NULL) {
1423 // Then give gen and higher generations a chance to expand and allocate the
1424 // object.
1425 do {
1426 result = gen->expand_and_allocate(obj_size, false);
1427 } while (result == NULL && (gen = next_gen(gen)) != NULL);
1428 }
1429
1430 if (result != NULL) {
1431 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
1432 }
1433 return oop(result);
1434 }
1435
1436 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
1437 jlong _time; // in ms
1438 jlong _now; // in ms
1439
1440 public:
1441 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
1442
1443 jlong time() { return _time; }
1444
1445 void do_generation(Generation* gen) {
1446 _time = MIN2(_time, gen->time_of_last_gc(_now));
1447 }
1448 };
1449
1450 jlong GenCollectedHeap::millis_since_last_gc() {
1451 jlong now = os::javaTimeMillis();
1452 GenTimeOfLastGCClosure tolgc_cl(now);
1453 // iterate over generations getting the oldest
1454 // time that a generation was collected
1455 generation_iterate(&tolgc_cl, false);
1456 tolgc_cl.do_generation(perm_gen());
1457 // XXX Despite the assert above, since javaTimeMillis()
1458 // doesnot guarantee monotonically increasing return
1459 // values (note, i didn't say "strictly monotonic"),
1460 // we need to guard against getting back a time
1461 // later than now. This should be fixed by basing
1462 // on someting like gethrtime() which guarantees
1463 // monotonicity. Note that cond_wait() is susceptible
1464 // to a similar problem, because its interface is
1465 // based on absolute time in the form of the
1466 // system time's notion of UCT. See also 4506635
1467 // for yet another problem of similar nature. XXX
1468 jlong retVal = now - tolgc_cl.time();
1469 if (retVal < 0) {
1470 NOT_PRODUCT(warning("time warp: %d", retVal);)
1471 return 0;
1472 }
1473 return retVal;
1474 }