1 /*
2 * Copyright (c) 2001, 2018, 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.inline.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/gcWhen.hpp"
36 #include "gc/shared/vmGCOperations.hpp"
37 #include "logging/log.hpp"
38 #include "memory/metaspace.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "oops/instanceMirrorKlass.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/init.hpp"
43 #include "runtime/thread.inline.hpp"
44 #include "runtime/threadSMR.hpp"
45 #include "runtime/vmThread.hpp"
46 #include "services/heapDumper.hpp"
47 #include "utilities/align.hpp"
48
49 class ClassLoaderData;
50
51 #ifdef ASSERT
52 int CollectedHeap::_fire_out_of_memory_count = 0;
53 #endif
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 MutexLockerEx 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 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
86 size_t capacity_in_words = capacity() / HeapWordSize;
87
88 return VirtualSpaceSummary(
89 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
90 }
91
92 GCHeapSummary CollectedHeap::create_heap_summary() {
93 VirtualSpaceSummary heap_space = create_heap_space_summary();
94 return GCHeapSummary(heap_space, used());
95 }
96
97 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
98 const MetaspaceSizes meta_space(
99 MetaspaceAux::committed_bytes(),
100 MetaspaceAux::used_bytes(),
101 MetaspaceAux::reserved_bytes());
102 const MetaspaceSizes data_space(
103 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
104 MetaspaceAux::used_bytes(Metaspace::NonClassType),
105 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
106 const MetaspaceSizes class_space(
107 MetaspaceAux::committed_bytes(Metaspace::ClassType),
108 MetaspaceAux::used_bytes(Metaspace::ClassType),
109 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
110
111 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
112 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
113 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
114 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
115
116 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
117 ms_chunk_free_list_summary, class_chunk_free_list_summary);
118 }
119
120 void CollectedHeap::print_heap_before_gc() {
121 Universe::print_heap_before_gc();
122 if (_gc_heap_log != NULL) {
123 _gc_heap_log->log_heap_before(this);
124 }
125 }
126
127 void CollectedHeap::print_heap_after_gc() {
128 Universe::print_heap_after_gc();
129 if (_gc_heap_log != NULL) {
130 _gc_heap_log->log_heap_after(this);
131 }
132 }
133
134 void CollectedHeap::print_on_error(outputStream* st) const {
135 st->print_cr("Heap:");
136 print_extended_on(st);
137 st->cr();
138
139 _barrier_set->print_on(st);
140 }
141
142 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
143 const GCHeapSummary& heap_summary = create_heap_summary();
144 gc_tracer->report_gc_heap_summary(when, heap_summary);
145
146 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
147 gc_tracer->report_metaspace_summary(when, metaspace_summary);
148 }
149
150 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
151 trace_heap(GCWhen::BeforeGC, gc_tracer);
152 }
153
154 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
155 trace_heap(GCWhen::AfterGC, gc_tracer);
156 }
157
158 // WhiteBox API support for concurrent collectors. These are the
159 // default implementations, for collectors which don't support this
160 // feature.
161 bool CollectedHeap::supports_concurrent_phase_control() const {
162 return false;
163 }
164
165 const char* const* CollectedHeap::concurrent_phases() const {
166 static const char* const result[] = { NULL };
167 return result;
168 }
169
170 bool CollectedHeap::request_concurrent_phase(const char* phase) {
171 return false;
172 }
173
174 // Memory state functions.
175
176
177 CollectedHeap::CollectedHeap() :
178 _barrier_set(NULL),
179 _is_gc_active(false),
180 _total_collections(0),
181 _total_full_collections(0),
182 _gc_cause(GCCause::_no_gc),
183 _gc_lastcause(GCCause::_no_gc)
184 {
185 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
186 const size_t elements_per_word = HeapWordSize / sizeof(jint);
187 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
188 max_len / elements_per_word);
189
190 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
191 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
192
193 if (UsePerfData) {
194 EXCEPTION_MARK;
195
196 // create the gc cause jvmstat counters
197 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
198 80, GCCause::to_string(_gc_cause), CHECK);
199
200 _perf_gc_lastcause =
201 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
202 80, GCCause::to_string(_gc_lastcause), CHECK);
203 }
204
205 // Create the ring log
206 if (LogEvents) {
207 _gc_heap_log = new GCHeapLog();
208 } else {
209 _gc_heap_log = NULL;
210 }
211 }
212
213 // This interface assumes that it's being called by the
214 // vm thread. It collects the heap assuming that the
215 // heap lock is already held and that we are executing in
216 // the context of the vm thread.
217 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
218 assert(Thread::current()->is_VM_thread(), "Precondition#1");
219 assert(Heap_lock->is_locked(), "Precondition#2");
220 GCCauseSetter gcs(this, cause);
221 switch (cause) {
222 case GCCause::_heap_inspection:
223 case GCCause::_heap_dump:
224 case GCCause::_metadata_GC_threshold : {
225 HandleMark hm;
226 do_full_collection(false); // don't clear all soft refs
227 break;
228 }
229 case GCCause::_metadata_GC_clear_soft_refs: {
230 HandleMark hm;
231 do_full_collection(true); // do clear all soft refs
232 break;
233 }
234 default:
235 ShouldNotReachHere(); // Unexpected use of this function
236 }
237 }
238
239 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
240 size_t word_size,
241 Metaspace::MetadataType mdtype) {
242 uint loop_count = 0;
243 uint gc_count = 0;
244 uint full_gc_count = 0;
245
246 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
247
248 do {
249 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
250 if (result != NULL) {
251 return result;
252 }
253
254 if (GCLocker::is_active_and_needs_gc()) {
255 // If the GCLocker is active, just expand and allocate.
256 // If that does not succeed, wait if this thread is not
257 // in a critical section itself.
258 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
259 if (result != NULL) {
260 return result;
261 }
262 JavaThread* jthr = JavaThread::current();
263 if (!jthr->in_critical()) {
264 // Wait for JNI critical section to be exited
265 GCLocker::stall_until_clear();
266 // The GC invoked by the last thread leaving the critical
267 // section will be a young collection and a full collection
268 // is (currently) needed for unloading classes so continue
269 // to the next iteration to get a full GC.
270 continue;
271 } else {
272 if (CheckJNICalls) {
273 fatal("Possible deadlock due to allocating while"
274 " in jni critical section");
275 }
276 return NULL;
277 }
278 }
279
280 { // Need lock to get self consistent gc_count's
281 MutexLocker ml(Heap_lock);
282 gc_count = Universe::heap()->total_collections();
283 full_gc_count = Universe::heap()->total_full_collections();
284 }
285
286 // Generate a VM operation
287 VM_CollectForMetadataAllocation op(loader_data,
288 word_size,
289 mdtype,
290 gc_count,
291 full_gc_count,
292 GCCause::_metadata_GC_threshold);
293 VMThread::execute(&op);
294
295 // If GC was locked out, try again. Check before checking success because the
296 // prologue could have succeeded and the GC still have been locked out.
297 if (op.gc_locked()) {
298 continue;
299 }
300
301 if (op.prologue_succeeded()) {
302 return op.result();
303 }
304 loop_count++;
305 if ((QueuedAllocationWarningCount > 0) &&
306 (loop_count % QueuedAllocationWarningCount == 0)) {
307 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
308 " size=" SIZE_FORMAT, loop_count, word_size);
309 }
310 } while (true); // Until a GC is done
311 }
312
313 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
314 _barrier_set = barrier_set;
315 BarrierSet::set_bs(barrier_set);
316 }
317
318 #ifndef PRODUCT
319 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
320 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
321 for (size_t slot = 0; slot < size; slot += 1) {
322 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
323 "Found badHeapWordValue in post-allocation check");
324 }
325 }
326 }
327
328 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
329 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
330 for (size_t slot = 0; slot < size; slot += 1) {
331 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
332 "Found non badHeapWordValue in pre-allocation check");
333 }
334 }
335 }
336 #endif // PRODUCT
337
338 #ifdef ASSERT
339 void CollectedHeap::check_for_valid_allocation_state() {
340 Thread *thread = Thread::current();
341 // How to choose between a pending exception and a potential
342 // OutOfMemoryError? Don't allow pending exceptions.
343 // This is a VM policy failure, so how do we exhaustively test it?
344 assert(!thread->has_pending_exception(),
345 "shouldn't be allocating with pending exception");
346 if (StrictSafepointChecks) {
347 assert(thread->allow_allocation(),
348 "Allocation done by thread for which allocation is blocked "
349 "by No_Allocation_Verifier!");
350 // Allocation of an oop can always invoke a safepoint,
351 // hence, the true argument
352 thread->check_for_valid_safepoint_state(true);
353 }
354 }
355 #endif
356
357 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
358
359 // Retain tlab and allocate object in shared space if
360 // the amount free in the tlab is too large to discard.
361 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
362 thread->tlab().record_slow_allocation(size);
363 return NULL;
364 }
365
366 // Discard tlab and allocate a new one.
367 // To minimize fragmentation, the last TLAB may be smaller than the rest.
368 size_t new_tlab_size = thread->tlab().compute_size(size);
369
370 thread->tlab().clear_before_allocation();
371
372 if (new_tlab_size == 0) {
373 return NULL;
374 }
375
376 // Allocate a new TLAB...
377 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
378 if (obj == NULL) {
379 return NULL;
380 }
381
382 AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);
383
384 if (ZeroTLAB) {
385 // ..and clear it.
386 Copy::zero_to_words(obj, new_tlab_size);
387 } else {
388 // ...and zap just allocated object.
389 #ifdef ASSERT
390 // Skip mangling the space corresponding to the object header to
391 // ensure that the returned space is not considered parsable by
392 // any concurrent GC thread.
393 size_t hdr_size = oopDesc::header_size();
394 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
395 #endif // ASSERT
396 }
397 thread->tlab().fill(obj, obj + size, new_tlab_size);
398 return obj;
399 }
400
401 size_t CollectedHeap::max_tlab_size() const {
402 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
403 // This restriction could be removed by enabling filling with multiple arrays.
404 // If we compute that the reasonable way as
405 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
406 // we'll overflow on the multiply, so we do the divide first.
407 // We actually lose a little by dividing first,
408 // but that just makes the TLAB somewhat smaller than the biggest array,
409 // which is fine, since we'll be able to fill that.
410 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
411 sizeof(jint) *
412 ((juint) max_jint / (size_t) HeapWordSize);
413 return align_down(max_int_size, MinObjAlignment);
414 }
415
416 size_t CollectedHeap::filler_array_hdr_size() {
417 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
418 }
419
420 size_t CollectedHeap::filler_array_min_size() {
421 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
422 }
423
424 #ifdef ASSERT
425 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
426 {
427 assert(words >= min_fill_size(), "too small to fill");
428 assert(is_object_aligned(words), "unaligned size");
429 assert(Universe::heap()->is_in_reserved(start), "not in heap");
430 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
431 }
432
433 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
434 {
435 if (ZapFillerObjects && zap) {
436 Copy::fill_to_words(start + filler_array_hdr_size(),
437 words - filler_array_hdr_size(), 0XDEAFBABE);
438 }
439 }
440 #endif // ASSERT
441
442 void
443 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
444 {
445 assert(words >= filler_array_min_size(), "too small for an array");
446 assert(words <= filler_array_max_size(), "too big for a single object");
447
448 const size_t payload_size = words - filler_array_hdr_size();
449 const size_t len = payload_size * HeapWordSize / sizeof(jint);
450 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
451
452 // Set the length first for concurrent GC.
453 ((arrayOop)start)->set_length((int)len);
454 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
455 DEBUG_ONLY(zap_filler_array(start, words, zap);)
456 }
457
458 void
459 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
460 {
461 assert(words <= filler_array_max_size(), "too big for a single object");
462
463 if (words >= filler_array_min_size()) {
464 fill_with_array(start, words, zap);
465 } else if (words > 0) {
466 assert(words == min_fill_size(), "unaligned size");
467 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
468 }
469 }
470
471 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
472 {
473 DEBUG_ONLY(fill_args_check(start, words);)
474 HandleMark hm; // Free handles before leaving.
475 fill_with_object_impl(start, words, zap);
476 }
477
478 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
479 {
480 DEBUG_ONLY(fill_args_check(start, words);)
481 HandleMark hm; // Free handles before leaving.
482
483 // Multiple objects may be required depending on the filler array maximum size. Fill
484 // the range up to that with objects that are filler_array_max_size sized. The
485 // remainder is filled with a single object.
486 const size_t min = min_fill_size();
487 const size_t max = filler_array_max_size();
488 while (words > max) {
489 const size_t cur = (words - max) >= min ? max : max - min;
490 fill_with_array(start, cur, zap);
491 start += cur;
492 words -= cur;
493 }
494
495 fill_with_object_impl(start, words, zap);
496 }
497
498 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
499 guarantee(false, "thread-local allocation buffers not supported");
500 return NULL;
501 }
502
503 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
504 // The second disjunct in the assertion below makes a concession
505 // for the start-up verification done while the VM is being
506 // created. Callers be careful that you know that mutators
507 // aren't going to interfere -- for instance, this is permissible
508 // if we are still single-threaded and have either not yet
509 // started allocating (nothing much to verify) or we have
510 // started allocating but are now a full-fledged JavaThread
511 // (and have thus made our TLAB's) available for filling.
512 assert(SafepointSynchronize::is_at_safepoint() ||
513 !is_init_completed(),
514 "Should only be called at a safepoint or at start-up"
515 " otherwise concurrent mutator activity may make heap "
516 " unparsable again");
517 const bool use_tlab = UseTLAB;
518 // The main thread starts allocating via a TLAB even before it
519 // has added itself to the threads list at vm boot-up.
520 JavaThreadIteratorWithHandle jtiwh;
521 assert(!use_tlab || jtiwh.length() > 0,
522 "Attempt to fill tlabs before main thread has been added"
523 " to threads list is doomed to failure!");
524 BarrierSet *bs = barrier_set();
525 for (; JavaThread *thread = jtiwh.next(); ) {
526 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
527 bs->make_parsable(thread);
528 }
529 }
530
531 void CollectedHeap::accumulate_statistics_all_tlabs() {
532 if (UseTLAB) {
533 assert(SafepointSynchronize::is_at_safepoint() ||
534 !is_init_completed(),
535 "should only accumulate statistics on tlabs at safepoint");
536
537 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
538 }
539 }
540
541 void CollectedHeap::resize_all_tlabs() {
542 if (UseTLAB) {
543 assert(SafepointSynchronize::is_at_safepoint() ||
544 !is_init_completed(),
545 "should only resize tlabs at safepoint");
546
547 ThreadLocalAllocBuffer::resize_all_tlabs();
548 }
549 }
550
551 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
552 assert(timer != NULL, "timer is null");
553 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
554 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
555 HeapDumper::dump_heap();
556 }
557
558 LogTarget(Trace, gc, classhisto) lt;
559 if (lt.is_enabled()) {
560 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
561 ResourceMark rm;
562 LogStream ls(lt);
563 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
564 inspector.doit();
565 }
566 }
567
568 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
569 full_gc_dump(timer, true);
570 }
571
572 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
573 full_gc_dump(timer, false);
574 }
575
576 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
577 // It is important to do this in a way such that concurrent readers can't
578 // temporarily think something is in the heap. (Seen this happen in asserts.)
579 _reserved.set_word_size(0);
580 _reserved.set_start(start);
581 _reserved.set_end(end);
582 }
583
584 void CollectedHeap::post_initialize() {
585 initialize_serviceability();
586 }