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