1 /*
2 * Copyright (c) 2001, 2019, 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/systemDictionary.hpp"
27 #include "gc/shared/allocTracer.hpp"
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/gcLocker.inline.hpp"
32 #include "gc/shared/gcHeapSummary.hpp"
33 #include "gc/shared/gcTrace.hpp"
34 #include "gc/shared/gcTraceTime.inline.hpp"
35 #include "gc/shared/gcVMOperations.hpp"
36 #include "gc/shared/gcWhen.hpp"
37 #include "gc/shared/memAllocator.hpp"
38 #include "logging/log.hpp"
39 #include "memory/metaspace.hpp"
40 #include "memory/resourceArea.hpp"
41 #include "memory/universe.hpp"
42 #include "oops/instanceMirrorKlass.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "runtime/handles.inline.hpp"
45 #include "runtime/init.hpp"
46 #include "runtime/thread.inline.hpp"
47 #include "runtime/threadSMR.hpp"
48 #include "runtime/vmThread.hpp"
49 #include "services/heapDumper.hpp"
50 #include "utilities/align.hpp"
51 #include "utilities/copy.hpp"
52
53 class ClassLoaderData;
54
55 size_t CollectedHeap::_filler_array_max_size = 0;
56
57 template <>
58 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
59 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
60 st->print_raw(m);
61 }
62
63 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
64 if (!should_log()) {
65 return;
66 }
67
68 double timestamp = fetch_timestamp();
69 MutexLocker ml(&_mutex, Mutex::_no_safepoint_check_flag);
70 int index = compute_log_index();
71 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
72 _records[index].timestamp = timestamp;
73 _records[index].data.is_before = before;
74 stringStream st(_records[index].data.buffer(), _records[index].data.size());
75
76 st.print_cr("{Heap %s GC invocations=%u (full %u):",
77 before ? "before" : "after",
78 heap->total_collections(),
79 heap->total_full_collections());
80
81 heap->print_on(&st);
82 st.print_cr("}");
83 }
84
85 size_t CollectedHeap::unused() const {
86 MutexLocker ml(Heap_lock);
87 return capacity() - used();
88 }
89
90 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
91 size_t capacity_in_words = capacity() / HeapWordSize;
92
93 return VirtualSpaceSummary(
94 _reserved.start(), _reserved.start() + capacity_in_words, _reserved.end());
95 }
96
97 GCHeapSummary CollectedHeap::create_heap_summary() {
98 VirtualSpaceSummary heap_space = create_heap_space_summary();
99 return GCHeapSummary(heap_space, used());
100 }
101
102 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
103 const MetaspaceSizes meta_space(
104 MetaspaceUtils::committed_bytes(),
105 MetaspaceUtils::used_bytes(),
106 MetaspaceUtils::reserved_bytes());
107 const MetaspaceSizes data_space(
108 MetaspaceUtils::committed_bytes(Metaspace::NonClassType),
109 MetaspaceUtils::used_bytes(Metaspace::NonClassType),
110 MetaspaceUtils::reserved_bytes(Metaspace::NonClassType));
111 const MetaspaceSizes class_space(
112 MetaspaceUtils::committed_bytes(Metaspace::ClassType),
113 MetaspaceUtils::used_bytes(Metaspace::ClassType),
114 MetaspaceUtils::reserved_bytes(Metaspace::ClassType));
115
116 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
117 MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);
118 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
119 MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);
120
121 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
122 ms_chunk_free_list_summary, class_chunk_free_list_summary);
123 }
124
125 void CollectedHeap::print_heap_before_gc() {
126 Universe::print_heap_before_gc();
127 if (_gc_heap_log != NULL) {
128 _gc_heap_log->log_heap_before(this);
129 }
130 }
131
132 void CollectedHeap::print_heap_after_gc() {
133 Universe::print_heap_after_gc();
134 if (_gc_heap_log != NULL) {
135 _gc_heap_log->log_heap_after(this);
136 }
137 }
138
139 void CollectedHeap::print() const { print_on(tty); }
140
141 void CollectedHeap::print_on_error(outputStream* st) const {
142 st->print_cr("Heap:");
143 print_extended_on(st);
144 st->cr();
145
146 BarrierSet::barrier_set()->print_on(st);
147 }
148
149 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
150 const GCHeapSummary& heap_summary = create_heap_summary();
151 gc_tracer->report_gc_heap_summary(when, heap_summary);
152
153 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
154 gc_tracer->report_metaspace_summary(when, metaspace_summary);
155 }
156
157 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
158 trace_heap(GCWhen::BeforeGC, gc_tracer);
159 }
160
161 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
162 trace_heap(GCWhen::AfterGC, gc_tracer);
163 }
164
165 // WhiteBox API support for concurrent collectors. These are the
166 // default implementations, for collectors which don't support this
167 // feature.
168 bool CollectedHeap::supports_concurrent_phase_control() const {
169 return false;
170 }
171
172 bool CollectedHeap::request_concurrent_phase(const char* phase) {
173 return false;
174 }
175
176 bool CollectedHeap::is_oop(oop object) const {
177 if (!is_object_aligned(object)) {
178 return false;
179 }
180
181 if (!is_in(object)) {
182 return false;
183 }
184
185 if (is_in(object->klass_or_null())) {
186 return false;
187 }
188
189 return true;
190 }
191
192 // Memory state functions.
193
194
195 CollectedHeap::CollectedHeap() :
196 _is_gc_active(false),
197 _total_collections(0),
198 _total_full_collections(0),
199 _gc_cause(GCCause::_no_gc),
200 _gc_lastcause(GCCause::_no_gc)
201 {
202 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
203 const size_t elements_per_word = HeapWordSize / sizeof(jint);
204 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
205 max_len / elements_per_word);
206
207 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
208 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
209
210 if (UsePerfData) {
211 EXCEPTION_MARK;
212
213 // create the gc cause jvmstat counters
214 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
215 80, GCCause::to_string(_gc_cause), CHECK);
216
217 _perf_gc_lastcause =
218 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
219 80, GCCause::to_string(_gc_lastcause), CHECK);
220 }
221
222 // Create the ring log
223 if (LogEvents) {
224 _gc_heap_log = new GCHeapLog();
225 } else {
226 _gc_heap_log = NULL;
227 }
228 }
229
230 // This interface assumes that it's being called by the
231 // vm thread. It collects the heap assuming that the
232 // heap lock is already held and that we are executing in
233 // the context of the vm thread.
234 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
235 assert(Thread::current()->is_VM_thread(), "Precondition#1");
236 assert(Heap_lock->is_locked(), "Precondition#2");
237 GCCauseSetter gcs(this, cause);
238 switch (cause) {
239 case GCCause::_heap_inspection:
240 case GCCause::_heap_dump:
241 case GCCause::_metadata_GC_threshold : {
242 HandleMark hm;
243 do_full_collection(false); // don't clear all soft refs
244 break;
245 }
246 case GCCause::_metadata_GC_clear_soft_refs: {
247 HandleMark hm;
248 do_full_collection(true); // do clear all soft refs
249 break;
250 }
251 default:
252 ShouldNotReachHere(); // Unexpected use of this function
253 }
254 }
255
256 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
257 size_t word_size,
258 Metaspace::MetadataType mdtype) {
259 uint loop_count = 0;
260 uint gc_count = 0;
261 uint full_gc_count = 0;
262
263 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
264
265 do {
266 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
267 if (result != NULL) {
268 return result;
269 }
270
271 if (GCLocker::is_active_and_needs_gc()) {
272 // If the GCLocker is active, just expand and allocate.
273 // If that does not succeed, wait if this thread is not
274 // in a critical section itself.
275 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
276 if (result != NULL) {
277 return result;
278 }
279 JavaThread* jthr = JavaThread::current();
280 if (!jthr->in_critical()) {
281 // Wait for JNI critical section to be exited
282 GCLocker::stall_until_clear();
283 // The GC invoked by the last thread leaving the critical
284 // section will be a young collection and a full collection
285 // is (currently) needed for unloading classes so continue
286 // to the next iteration to get a full GC.
287 continue;
288 } else {
289 if (CheckJNICalls) {
290 fatal("Possible deadlock due to allocating while"
291 " in jni critical section");
292 }
293 return NULL;
294 }
295 }
296
297 { // Need lock to get self consistent gc_count's
298 MutexLocker ml(Heap_lock);
299 gc_count = Universe::heap()->total_collections();
300 full_gc_count = Universe::heap()->total_full_collections();
301 }
302
303 // Generate a VM operation
304 VM_CollectForMetadataAllocation op(loader_data,
305 word_size,
306 mdtype,
307 gc_count,
308 full_gc_count,
309 GCCause::_metadata_GC_threshold);
310 VMThread::execute(&op);
311
312 // If GC was locked out, try again. Check before checking success because the
313 // prologue could have succeeded and the GC still have been locked out.
314 if (op.gc_locked()) {
315 continue;
316 }
317
318 if (op.prologue_succeeded()) {
319 return op.result();
320 }
321 loop_count++;
322 if ((QueuedAllocationWarningCount > 0) &&
323 (loop_count % QueuedAllocationWarningCount == 0)) {
324 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
325 " size=" SIZE_FORMAT, loop_count, word_size);
326 }
327 } while (true); // Until a GC is done
328 }
329
330 MemoryUsage CollectedHeap::memory_usage() {
331 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
332 }
333
334
335 #ifndef PRODUCT
336 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
337 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
338 for (size_t slot = 0; slot < size; slot += 1) {
339 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
340 "Found non badHeapWordValue in pre-allocation check");
341 }
342 }
343 }
344 #endif // PRODUCT
345
346 void CollectedHeap::check_oop_location(void* addr) const {
347 assert(is_object_aligned(addr), "address is not aligned");
348 assert(_reserved.contains(addr), "address is not in reserved heap");
349 }
350
351 size_t CollectedHeap::max_tlab_size() const {
352 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
353 // This restriction could be removed by enabling filling with multiple arrays.
354 // If we compute that the reasonable way as
355 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
356 // we'll overflow on the multiply, so we do the divide first.
357 // We actually lose a little by dividing first,
358 // but that just makes the TLAB somewhat smaller than the biggest array,
359 // which is fine, since we'll be able to fill that.
360 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
361 sizeof(jint) *
362 ((juint) max_jint / (size_t) HeapWordSize);
363 return align_down(max_int_size, MinObjAlignment);
364 }
365
366 size_t CollectedHeap::filler_array_hdr_size() {
367 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
368 }
369
370 size_t CollectedHeap::filler_array_min_size() {
371 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
372 }
373
374 #ifdef ASSERT
375 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
376 {
377 assert(words >= min_fill_size(), "too small to fill");
378 assert(is_object_aligned(words), "unaligned size");
379 DEBUG_ONLY(Universe::heap()->check_oop_location(start);)
380 DEBUG_ONLY(Universe::heap()->check_oop_location(start + words - MinObjAlignment);)
381 }
382
383 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
384 {
385 if (ZapFillerObjects && zap) {
386 Copy::fill_to_words(start + filler_array_hdr_size(),
387 words - filler_array_hdr_size(), 0XDEAFBABE);
388 }
389 }
390 #endif // ASSERT
391
392 void
393 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
394 {
395 assert(words >= filler_array_min_size(), "too small for an array");
396 assert(words <= filler_array_max_size(), "too big for a single object");
397
398 const size_t payload_size = words - filler_array_hdr_size();
399 const size_t len = payload_size * HeapWordSize / sizeof(jint);
400 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
401
402 ObjArrayAllocator allocator(Universe::intArrayKlassObj(), words, (int)len, /* do_zero */ false);
403 allocator.initialize(start);
404 DEBUG_ONLY(zap_filler_array(start, words, zap);)
405 }
406
407 void
408 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
409 {
410 assert(words <= filler_array_max_size(), "too big for a single object");
411
412 if (words >= filler_array_min_size()) {
413 fill_with_array(start, words, zap);
414 } else if (words > 0) {
415 assert(words == min_fill_size(), "unaligned size");
416 ObjAllocator allocator(SystemDictionary::Object_klass(), words);
417 allocator.initialize(start);
418 }
419 }
420
421 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
422 {
423 DEBUG_ONLY(fill_args_check(start, words);)
424 HandleMark hm; // Free handles before leaving.
425 fill_with_object_impl(start, words, zap);
426 }
427
428 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
429 {
430 DEBUG_ONLY(fill_args_check(start, words);)
431 HandleMark hm; // Free handles before leaving.
432
433 // Multiple objects may be required depending on the filler array maximum size. Fill
434 // the range up to that with objects that are filler_array_max_size sized. The
435 // remainder is filled with a single object.
436 const size_t min = min_fill_size();
437 const size_t max = filler_array_max_size();
438 while (words > max) {
439 const size_t cur = (words - max) >= min ? max : max - min;
440 fill_with_array(start, cur, zap);
441 start += cur;
442 words -= cur;
443 }
444
445 fill_with_object_impl(start, words, zap);
446 }
447
448 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
449 CollectedHeap::fill_with_object(start, end, zap);
450 }
451
452 size_t CollectedHeap::min_dummy_object_size() const {
453 return oopDesc::header_size();
454 }
455
456 size_t CollectedHeap::tlab_alloc_reserve() const {
457 size_t min_size = min_dummy_object_size();
458 return min_size > (size_t)MinObjAlignment ? align_object_size(min_size) : 0;
459 }
460
461 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
462 size_t requested_size,
463 size_t* actual_size) {
464 guarantee(false, "thread-local allocation buffers not supported");
465 return NULL;
466 }
467
468 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
469 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
470 "Should only be called at a safepoint or at start-up");
471
472 ThreadLocalAllocStats stats;
473
474 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
475 BarrierSet::barrier_set()->make_parsable(thread);
476 if (UseTLAB) {
477 if (retire_tlabs) {
478 thread->tlab().retire(&stats);
479 } else {
480 thread->tlab().make_parsable();
481 }
482 }
483 }
484
485 stats.publish();
486 }
487
488 void CollectedHeap::resize_all_tlabs() {
489 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
490 "Should only resize tlabs at safepoint");
491
492 if (UseTLAB && ResizeTLAB) {
493 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
494 thread->tlab().resize();
495 }
496 }
497 }
498
499 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
500 assert(timer != NULL, "timer is null");
501 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
502 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
503 HeapDumper::dump_heap();
504 }
505
506 LogTarget(Trace, gc, classhisto) lt;
507 if (lt.is_enabled()) {
508 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
509 ResourceMark rm;
510 LogStream ls(lt);
511 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
512 inspector.doit();
513 }
514 }
515
516 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
517 full_gc_dump(timer, true);
518 }
519
520 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
521 full_gc_dump(timer, false);
522 }
523
524 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) {
525 // It is important to do this in a way such that concurrent readers can't
526 // temporarily think something is in the heap. (Seen this happen in asserts.)
527 _reserved.set_word_size(0);
528 _reserved.set_start((HeapWord*)rs.base());
529 _reserved.set_end((HeapWord*)rs.end());
530 }
531
532 void CollectedHeap::post_initialize() {
533 initialize_serviceability();
534 }
535
536 #ifndef PRODUCT
537
538 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
539 // Access to count is not atomic; the value does not have to be exact.
540 if (PromotionFailureALot) {
541 const size_t gc_num = total_collections();
542 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
543 if (elapsed_gcs >= PromotionFailureALotInterval) {
544 // Test for unsigned arithmetic wrap-around.
545 if (++*count >= PromotionFailureALotCount) {
546 *count = 0;
547 return true;
548 }
549 }
550 }
551 return false;
552 }
553
554 bool CollectedHeap::promotion_should_fail() {
555 return promotion_should_fail(&_promotion_failure_alot_count);
556 }
557
558 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
559 if (PromotionFailureALot) {
560 _promotion_failure_alot_gc_number = total_collections();
561 *count = 0;
562 }
563 }
564
565 void CollectedHeap::reset_promotion_should_fail() {
566 reset_promotion_should_fail(&_promotion_failure_alot_count);
567 }
568
569 #endif // #ifndef PRODUCT
570
571 bool CollectedHeap::supports_object_pinning() const {
572 return false;
573 }
574
575 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
576 ShouldNotReachHere();
577 return NULL;
578 }
579
580 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
581 ShouldNotReachHere();
582 }
583
584 void CollectedHeap::deduplicate_string(oop str) {
585 // Do nothing, unless overridden in subclass.
586 }
587
588 size_t CollectedHeap::obj_size(oop obj) const {
589 return obj->size();
590 }
591
592 uint32_t CollectedHeap::hash_oop(oop obj) const {
593 const uintptr_t addr = cast_from_oop<uintptr_t>(obj);
594 return static_cast<uint32_t>(addr >> LogMinObjAlignment);
595 }