1 /*
2 * Copyright (c) 2001, 2020, 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* bs = BarrierSet::barrier_set();
147 if (bs != NULL) {
148 bs->print_on(st);
149 }
150 }
151
152 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
153 const GCHeapSummary& heap_summary = create_heap_summary();
154 gc_tracer->report_gc_heap_summary(when, heap_summary);
155
156 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
157 gc_tracer->report_metaspace_summary(when, metaspace_summary);
158 }
159
160 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
161 trace_heap(GCWhen::BeforeGC, gc_tracer);
162 }
163
164 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
165 trace_heap(GCWhen::AfterGC, gc_tracer);
166 }
167
168 // Default implementation, for collectors that don't support the feature.
169 bool CollectedHeap::supports_concurrent_gc_breakpoints() const {
170 return false;
171 }
172
173 bool CollectedHeap::is_oop(oop object) const {
174 if (!is_object_aligned(object)) {
175 return false;
176 }
177
178 if (!is_in(object)) {
179 return false;
180 }
181
182 if (is_in(object->klass_or_null())) {
183 return false;
184 }
185
186 return true;
187 }
188
189 // Memory state functions.
190
191
192 CollectedHeap::CollectedHeap() :
193 _is_gc_active(false),
194 _total_collections(0),
195 _total_full_collections(0),
196 _gc_cause(GCCause::_no_gc),
197 _gc_lastcause(GCCause::_no_gc)
198 {
199 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
200 const size_t elements_per_word = HeapWordSize / sizeof(jint);
201 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
202 max_len / elements_per_word);
203
204 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
205 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
206
207 if (UsePerfData) {
208 EXCEPTION_MARK;
209
210 // create the gc cause jvmstat counters
211 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
212 80, GCCause::to_string(_gc_cause), CHECK);
213
214 _perf_gc_lastcause =
215 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
216 80, GCCause::to_string(_gc_lastcause), CHECK);
217 }
218
219 // Create the ring log
220 if (LogEvents) {
221 _gc_heap_log = new GCHeapLog();
222 } else {
223 _gc_heap_log = NULL;
224 }
225 }
226
227 // This interface assumes that it's being called by the
228 // vm thread. It collects the heap assuming that the
229 // heap lock is already held and that we are executing in
230 // the context of the vm thread.
231 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
232 assert(Thread::current()->is_VM_thread(), "Precondition#1");
233 assert(Heap_lock->is_locked(), "Precondition#2");
234 GCCauseSetter gcs(this, cause);
235 switch (cause) {
236 case GCCause::_heap_inspection:
237 case GCCause::_heap_dump:
238 case GCCause::_metadata_GC_threshold : {
239 HandleMark hm;
240 do_full_collection(false); // don't clear all soft refs
241 break;
242 }
243 case GCCause::_archive_time_gc:
244 case GCCause::_metadata_GC_clear_soft_refs: {
245 HandleMark hm;
246 do_full_collection(true); // do clear all soft refs
247 break;
248 }
249 default:
250 ShouldNotReachHere(); // Unexpected use of this function
251 }
252 }
253
254 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
255 size_t word_size,
256 Metaspace::MetadataType mdtype) {
257 uint loop_count = 0;
258 uint gc_count = 0;
259 uint full_gc_count = 0;
260
261 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
262
263 do {
264 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
265 if (result != NULL) {
266 return result;
267 }
268
269 if (GCLocker::is_active_and_needs_gc()) {
270 // If the GCLocker is active, just expand and allocate.
271 // If that does not succeed, wait if this thread is not
272 // in a critical section itself.
273 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
274 if (result != NULL) {
275 return result;
276 }
277 JavaThread* jthr = JavaThread::current();
278 if (!jthr->in_critical()) {
279 // Wait for JNI critical section to be exited
280 GCLocker::stall_until_clear();
281 // The GC invoked by the last thread leaving the critical
282 // section will be a young collection and a full collection
283 // is (currently) needed for unloading classes so continue
284 // to the next iteration to get a full GC.
285 continue;
286 } else {
287 if (CheckJNICalls) {
288 fatal("Possible deadlock due to allocating while"
289 " in jni critical section");
290 }
291 return NULL;
292 }
293 }
294
295 { // Need lock to get self consistent gc_count's
296 MutexLocker ml(Heap_lock);
297 gc_count = Universe::heap()->total_collections();
298 full_gc_count = Universe::heap()->total_full_collections();
299 }
300
301 // Generate a VM operation
302 VM_CollectForMetadataAllocation op(loader_data,
303 word_size,
304 mdtype,
305 gc_count,
306 full_gc_count,
307 GCCause::_metadata_GC_threshold);
308 VMThread::execute(&op);
309
310 // If GC was locked out, try again. Check before checking success because the
311 // prologue could have succeeded and the GC still have been locked out.
312 if (op.gc_locked()) {
313 continue;
314 }
315
316 if (op.prologue_succeeded()) {
317 return op.result();
318 }
319 loop_count++;
320 if ((QueuedAllocationWarningCount > 0) &&
321 (loop_count % QueuedAllocationWarningCount == 0)) {
322 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
323 " size=" SIZE_FORMAT, loop_count, word_size);
324 }
325 } while (true); // Until a GC is done
326 }
327
328 MemoryUsage CollectedHeap::memory_usage() {
329 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
330 }
331
332
333 #ifndef PRODUCT
334 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
335 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
336 // please note mismatch between size (in 32/64 bit words), and ju_addr that always point to a 32 bit word
337 for (juint* ju_addr = reinterpret_cast<juint*>(addr); ju_addr < reinterpret_cast<juint*>(addr + size); ++ju_addr) {
338 assert(*ju_addr == badHeapWordVal, "Found non badHeapWordValue in pre-allocation check");
339 }
340 }
341 }
342 #endif // PRODUCT
343
344 size_t CollectedHeap::max_tlab_size() const {
345 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
346 // This restriction could be removed by enabling filling with multiple arrays.
347 // If we compute that the reasonable way as
348 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
349 // we'll overflow on the multiply, so we do the divide first.
350 // We actually lose a little by dividing first,
351 // but that just makes the TLAB somewhat smaller than the biggest array,
352 // which is fine, since we'll be able to fill that.
353 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
354 sizeof(jint) *
355 ((juint) max_jint / (size_t) HeapWordSize);
356 return align_down(max_int_size, MinObjAlignment);
357 }
358
359 size_t CollectedHeap::filler_array_hdr_size() {
360 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
361 }
362
363 size_t CollectedHeap::filler_array_min_size() {
364 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
365 }
366
367 #ifdef ASSERT
368 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
369 {
370 assert(words >= min_fill_size(), "too small to fill");
371 assert(is_object_aligned(words), "unaligned size");
372 }
373
374 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
375 {
376 if (ZapFillerObjects && zap) {
377 Copy::fill_to_words(start + filler_array_hdr_size(),
378 words - filler_array_hdr_size(), 0XDEAFBABE);
379 }
380 }
381 #endif // ASSERT
382
383 void
384 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
385 {
386 assert(words >= filler_array_min_size(), "too small for an array");
387 assert(words <= filler_array_max_size(), "too big for a single object");
388
389 const size_t payload_size = words - filler_array_hdr_size();
390 const size_t len = payload_size * HeapWordSize / sizeof(jint);
391 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
392
393 ObjArrayAllocator allocator(Universe::intArrayKlassObj(), words, (int)len, /* do_zero */ false);
394 allocator.initialize(start);
395 DEBUG_ONLY(zap_filler_array(start, words, zap);)
396 }
397
398 void
399 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
400 {
401 assert(words <= filler_array_max_size(), "too big for a single object");
402
403 if (words >= filler_array_min_size()) {
404 fill_with_array(start, words, zap);
405 } else if (words > 0) {
406 assert(words == min_fill_size(), "unaligned size");
407 ObjAllocator allocator(SystemDictionary::Object_klass(), words);
408 allocator.initialize(start);
409 }
410 }
411
412 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
413 {
414 DEBUG_ONLY(fill_args_check(start, words);)
415 HandleMark hm; // Free handles before leaving.
416 fill_with_object_impl(start, words, zap);
417 }
418
419 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
420 {
421 DEBUG_ONLY(fill_args_check(start, words);)
422 HandleMark hm; // Free handles before leaving.
423
424 // Multiple objects may be required depending on the filler array maximum size. Fill
425 // the range up to that with objects that are filler_array_max_size sized. The
426 // remainder is filled with a single object.
427 const size_t min = min_fill_size();
428 const size_t max = filler_array_max_size();
429 while (words > max) {
430 const size_t cur = (words - max) >= min ? max : max - min;
431 fill_with_array(start, cur, zap);
432 start += cur;
433 words -= cur;
434 }
435
436 fill_with_object_impl(start, words, zap);
437 }
438
439 void CollectedHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
440 CollectedHeap::fill_with_object(start, end, zap);
441 }
442
443 size_t CollectedHeap::min_dummy_object_size() const {
444 return oopDesc::header_size();
445 }
446
447 size_t CollectedHeap::tlab_alloc_reserve() const {
448 size_t min_size = min_dummy_object_size();
449 return min_size > (size_t)MinObjAlignment ? align_object_size(min_size) : 0;
450 }
451
452 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
453 size_t requested_size,
454 size_t* actual_size) {
455 guarantee(false, "thread-local allocation buffers not supported");
456 return NULL;
457 }
458
459 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
460 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
461 "Should only be called at a safepoint or at start-up");
462
463 ThreadLocalAllocStats stats;
464
465 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
466 BarrierSet::barrier_set()->make_parsable(thread);
467 if (UseTLAB) {
468 if (retire_tlabs) {
469 thread->tlab().retire(&stats);
470 } else {
471 thread->tlab().make_parsable();
472 }
473 }
474 }
475
476 stats.publish();
477 }
478
479 void CollectedHeap::resize_all_tlabs() {
480 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
481 "Should only resize tlabs at safepoint");
482
483 if (UseTLAB && ResizeTLAB) {
484 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
485 thread->tlab().resize();
486 }
487 }
488 }
489
490 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
491 assert(timer != NULL, "timer is null");
492 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
493 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
494 HeapDumper::dump_heap();
495 }
496
497 LogTarget(Trace, gc, classhisto) lt;
498 if (lt.is_enabled()) {
499 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
500 ResourceMark rm;
501 LogStream ls(lt);
502 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
503 inspector.doit();
504 }
505 }
506
507 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
508 full_gc_dump(timer, true);
509 }
510
511 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
512 full_gc_dump(timer, false);
513 }
514
515 void CollectedHeap::initialize_reserved_region(const ReservedHeapSpace& rs) {
516 // It is important to do this in a way such that concurrent readers can't
517 // temporarily think something is in the heap. (Seen this happen in asserts.)
518 _reserved.set_word_size(0);
519 _reserved.set_start((HeapWord*)rs.base());
520 _reserved.set_end((HeapWord*)rs.end());
521 }
522
523 void CollectedHeap::post_initialize() {
524 initialize_serviceability();
525 }
526
527 #ifndef PRODUCT
528
529 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
530 // Access to count is not atomic; the value does not have to be exact.
531 if (PromotionFailureALot) {
532 const size_t gc_num = total_collections();
533 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
534 if (elapsed_gcs >= PromotionFailureALotInterval) {
535 // Test for unsigned arithmetic wrap-around.
536 if (++*count >= PromotionFailureALotCount) {
537 *count = 0;
538 return true;
539 }
540 }
541 }
542 return false;
543 }
544
545 bool CollectedHeap::promotion_should_fail() {
546 return promotion_should_fail(&_promotion_failure_alot_count);
547 }
548
549 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
550 if (PromotionFailureALot) {
551 _promotion_failure_alot_gc_number = total_collections();
552 *count = 0;
553 }
554 }
555
556 void CollectedHeap::reset_promotion_should_fail() {
557 reset_promotion_should_fail(&_promotion_failure_alot_count);
558 }
559
560 #endif // #ifndef PRODUCT
561
562 bool CollectedHeap::supports_object_pinning() const {
563 return false;
564 }
565
566 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
567 ShouldNotReachHere();
568 return NULL;
569 }
570
571 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
572 ShouldNotReachHere();
573 }
574
575 void CollectedHeap::deduplicate_string(oop str) {
576 // Do nothing, unless overridden in subclass.
577 }
578
579 size_t CollectedHeap::obj_size(oop obj) const {
580 return obj->size();
581 }
582
583 uint32_t CollectedHeap::hash_oop(oop obj) const {
584 const uintptr_t addr = cast_from_oop<uintptr_t>(obj);
585 return static_cast<uint32_t>(addr >> LogMinObjAlignment);
586 }