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 "services/heapDumper.hpp"
46 #include "utilities/align.hpp"
47
48 class ClassLoaderData;
49
50 #ifdef ASSERT
51 int CollectedHeap::_fire_out_of_memory_count = 0;
52 #endif
53
54 size_t CollectedHeap::_filler_array_max_size = 0;
55
56 template <>
57 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
58 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
59 st->print_raw(m);
60 }
61
62 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
63 if (!should_log()) {
64 return;
65 }
66
67 double timestamp = fetch_timestamp();
68 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
69 int index = compute_log_index();
70 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
71 _records[index].timestamp = timestamp;
72 _records[index].data.is_before = before;
73 stringStream st(_records[index].data.buffer(), _records[index].data.size());
74
75 st.print_cr("{Heap %s GC invocations=%u (full %u):",
76 before ? "before" : "after",
77 heap->total_collections(),
78 heap->total_full_collections());
79
80 heap->print_on(&st);
81 st.print_cr("}");
82 }
83
84 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
85 size_t capacity_in_words = capacity() / HeapWordSize;
86
87 return VirtualSpaceSummary(
88 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
89 }
90
91 GCHeapSummary CollectedHeap::create_heap_summary() {
92 VirtualSpaceSummary heap_space = create_heap_space_summary();
93 return GCHeapSummary(heap_space, used());
94 }
95
96 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
97 const MetaspaceSizes meta_space(
98 MetaspaceAux::committed_bytes(),
99 MetaspaceAux::used_bytes(),
100 MetaspaceAux::reserved_bytes());
101 const MetaspaceSizes data_space(
102 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
103 MetaspaceAux::used_bytes(Metaspace::NonClassType),
104 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
105 const MetaspaceSizes class_space(
106 MetaspaceAux::committed_bytes(Metaspace::ClassType),
107 MetaspaceAux::used_bytes(Metaspace::ClassType),
108 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
109
110 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
111 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
112 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
113 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
114
115 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
116 ms_chunk_free_list_summary, class_chunk_free_list_summary);
117 }
118
119 void CollectedHeap::print_heap_before_gc() {
120 Universe::print_heap_before_gc();
121 if (_gc_heap_log != NULL) {
122 _gc_heap_log->log_heap_before(this);
123 }
124 }
125
126 void CollectedHeap::print_heap_after_gc() {
127 Universe::print_heap_after_gc();
128 if (_gc_heap_log != NULL) {
129 _gc_heap_log->log_heap_after(this);
130 }
131 }
132
133 void CollectedHeap::print_on_error(outputStream* st) const {
134 st->print_cr("Heap:");
135 print_extended_on(st);
136 st->cr();
137
138 _barrier_set->print_on(st);
139 }
140
141 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
142 const GCHeapSummary& heap_summary = create_heap_summary();
143 gc_tracer->report_gc_heap_summary(when, heap_summary);
144
145 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
146 gc_tracer->report_metaspace_summary(when, metaspace_summary);
147 }
148
149 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
150 trace_heap(GCWhen::BeforeGC, gc_tracer);
151 }
152
153 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
154 trace_heap(GCWhen::AfterGC, gc_tracer);
155 }
156
157 // WhiteBox API support for concurrent collectors. These are the
158 // default implementations, for collectors which don't support this
159 // feature.
160 bool CollectedHeap::supports_concurrent_phase_control() const {
161 return false;
162 }
163
164 const char* const* CollectedHeap::concurrent_phases() const {
165 static const char* const result[] = { NULL };
166 return result;
167 }
168
169 bool CollectedHeap::request_concurrent_phase(const char* phase) {
170 return false;
171 }
172
173 // Memory state functions.
174
175
176 CollectedHeap::CollectedHeap() :
177 _barrier_set(NULL),
178 _is_gc_active(false),
179 _total_collections(0),
180 _total_full_collections(0),
181 _gc_cause(GCCause::_no_gc),
182 _gc_lastcause(GCCause::_no_gc)
183 {
184 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
185 const size_t elements_per_word = HeapWordSize / sizeof(jint);
186 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
187 max_len / elements_per_word);
188
189 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
190 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
191
192 if (UsePerfData) {
193 EXCEPTION_MARK;
194
195 // create the gc cause jvmstat counters
196 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
197 80, GCCause::to_string(_gc_cause), CHECK);
198
199 _perf_gc_lastcause =
200 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
201 80, GCCause::to_string(_gc_lastcause), CHECK);
202 }
203
204 // Create the ring log
205 if (LogEvents) {
206 _gc_heap_log = new GCHeapLog();
207 } else {
208 _gc_heap_log = NULL;
209 }
210 }
211
212 // This interface assumes that it's being called by the
213 // vm thread. It collects the heap assuming that the
214 // heap lock is already held and that we are executing in
215 // the context of the vm thread.
216 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
217 assert(Thread::current()->is_VM_thread(), "Precondition#1");
218 assert(Heap_lock->is_locked(), "Precondition#2");
219 GCCauseSetter gcs(this, cause);
220 switch (cause) {
221 case GCCause::_heap_inspection:
222 case GCCause::_heap_dump:
223 case GCCause::_metadata_GC_threshold : {
224 HandleMark hm;
225 do_full_collection(false); // don't clear all soft refs
226 break;
227 }
228 case GCCause::_metadata_GC_clear_soft_refs: {
229 HandleMark hm;
230 do_full_collection(true); // do clear all soft refs
231 break;
232 }
233 default:
234 ShouldNotReachHere(); // Unexpected use of this function
235 }
236 }
237
238 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
239 size_t word_size,
240 Metaspace::MetadataType mdtype) {
241 return MetaspaceGC::satisfy_failed_metadata_allocation(loader_data, word_size, mdtype);
242 }
243
244 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
245 _barrier_set = barrier_set;
246 BarrierSet::set_bs(barrier_set);
247 }
248
249 #ifndef PRODUCT
250 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
251 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
252 for (size_t slot = 0; slot < size; slot += 1) {
253 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
254 "Found badHeapWordValue in post-allocation check");
255 }
256 }
257 }
258
259 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
260 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
261 for (size_t slot = 0; slot < size; slot += 1) {
262 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
263 "Found non badHeapWordValue in pre-allocation check");
264 }
265 }
266 }
267 #endif // PRODUCT
268
269 #ifdef ASSERT
270 void CollectedHeap::check_for_valid_allocation_state() {
271 Thread *thread = Thread::current();
272 // How to choose between a pending exception and a potential
273 // OutOfMemoryError? Don't allow pending exceptions.
274 // This is a VM policy failure, so how do we exhaustively test it?
275 assert(!thread->has_pending_exception(),
276 "shouldn't be allocating with pending exception");
277 if (StrictSafepointChecks) {
278 assert(thread->allow_allocation(),
279 "Allocation done by thread for which allocation is blocked "
280 "by No_Allocation_Verifier!");
281 // Allocation of an oop can always invoke a safepoint,
282 // hence, the true argument
283 thread->check_for_valid_safepoint_state(true);
284 }
285 }
286 #endif
287
288 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
289
290 // Retain tlab and allocate object in shared space if
291 // the amount free in the tlab is too large to discard.
292 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
293 thread->tlab().record_slow_allocation(size);
294 return NULL;
295 }
296
297 // Discard tlab and allocate a new one.
298 // To minimize fragmentation, the last TLAB may be smaller than the rest.
299 size_t new_tlab_size = thread->tlab().compute_size(size);
300
301 thread->tlab().clear_before_allocation();
302
303 if (new_tlab_size == 0) {
304 return NULL;
305 }
306
307 // Allocate a new TLAB...
308 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
309 if (obj == NULL) {
310 return NULL;
311 }
312
313 AllocTracer::send_allocation_in_new_tlab(klass, obj, new_tlab_size * HeapWordSize, size * HeapWordSize, thread);
314
315 if (ZeroTLAB) {
316 // ..and clear it.
317 Copy::zero_to_words(obj, new_tlab_size);
318 } else {
319 // ...and zap just allocated object.
320 #ifdef ASSERT
321 // Skip mangling the space corresponding to the object header to
322 // ensure that the returned space is not considered parsable by
323 // any concurrent GC thread.
324 size_t hdr_size = oopDesc::header_size();
325 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
326 #endif // ASSERT
327 }
328 thread->tlab().fill(obj, obj + size, new_tlab_size);
329 return obj;
330 }
331
332 size_t CollectedHeap::max_tlab_size() const {
333 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
334 // This restriction could be removed by enabling filling with multiple arrays.
335 // If we compute that the reasonable way as
336 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
337 // we'll overflow on the multiply, so we do the divide first.
338 // We actually lose a little by dividing first,
339 // but that just makes the TLAB somewhat smaller than the biggest array,
340 // which is fine, since we'll be able to fill that.
341 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
342 sizeof(jint) *
343 ((juint) max_jint / (size_t) HeapWordSize);
344 return align_down(max_int_size, MinObjAlignment);
345 }
346
347 size_t CollectedHeap::filler_array_hdr_size() {
348 return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
349 }
350
351 size_t CollectedHeap::filler_array_min_size() {
352 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
353 }
354
355 #ifdef ASSERT
356 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
357 {
358 assert(words >= min_fill_size(), "too small to fill");
359 assert(is_object_aligned(words), "unaligned size");
360 assert(Universe::heap()->is_in_reserved(start), "not in heap");
361 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
362 }
363
364 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
365 {
366 if (ZapFillerObjects && zap) {
367 Copy::fill_to_words(start + filler_array_hdr_size(),
368 words - filler_array_hdr_size(), 0XDEAFBABE);
369 }
370 }
371 #endif // ASSERT
372
373 void
374 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
375 {
376 assert(words >= filler_array_min_size(), "too small for an array");
377 assert(words <= filler_array_max_size(), "too big for a single object");
378
379 const size_t payload_size = words - filler_array_hdr_size();
380 const size_t len = payload_size * HeapWordSize / sizeof(jint);
381 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
382
383 // Set the length first for concurrent GC.
384 ((arrayOop)start)->set_length((int)len);
385 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
386 DEBUG_ONLY(zap_filler_array(start, words, zap);)
387 }
388
389 void
390 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
391 {
392 assert(words <= filler_array_max_size(), "too big for a single object");
393
394 if (words >= filler_array_min_size()) {
395 fill_with_array(start, words, zap);
396 } else if (words > 0) {
397 assert(words == min_fill_size(), "unaligned size");
398 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
399 }
400 }
401
402 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
403 {
404 DEBUG_ONLY(fill_args_check(start, words);)
405 HandleMark hm; // Free handles before leaving.
406 fill_with_object_impl(start, words, zap);
407 }
408
409 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
410 {
411 DEBUG_ONLY(fill_args_check(start, words);)
412 HandleMark hm; // Free handles before leaving.
413
414 // Multiple objects may be required depending on the filler array maximum size. Fill
415 // the range up to that with objects that are filler_array_max_size sized. The
416 // remainder is filled with a single object.
417 const size_t min = min_fill_size();
418 const size_t max = filler_array_max_size();
419 while (words > max) {
420 const size_t cur = (words - max) >= min ? max : max - min;
421 fill_with_array(start, cur, zap);
422 start += cur;
423 words -= cur;
424 }
425
426 fill_with_object_impl(start, words, zap);
427 }
428
429 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
430 guarantee(false, "thread-local allocation buffers not supported");
431 return NULL;
432 }
433
434 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
435 // The second disjunct in the assertion below makes a concession
436 // for the start-up verification done while the VM is being
437 // created. Callers be careful that you know that mutators
438 // aren't going to interfere -- for instance, this is permissible
439 // if we are still single-threaded and have either not yet
440 // started allocating (nothing much to verify) or we have
441 // started allocating but are now a full-fledged JavaThread
442 // (and have thus made our TLAB's) available for filling.
443 assert(SafepointSynchronize::is_at_safepoint() ||
444 !is_init_completed(),
445 "Should only be called at a safepoint or at start-up"
446 " otherwise concurrent mutator activity may make heap "
447 " unparsable again");
448 const bool use_tlab = UseTLAB;
449 // The main thread starts allocating via a TLAB even before it
450 // has added itself to the threads list at vm boot-up.
451 JavaThreadIteratorWithHandle jtiwh;
452 assert(!use_tlab || jtiwh.length() > 0,
453 "Attempt to fill tlabs before main thread has been added"
454 " to threads list is doomed to failure!");
455 BarrierSet *bs = barrier_set();
456 for (; JavaThread *thread = jtiwh.next(); ) {
457 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
458 bs->make_parsable(thread);
459 }
460 }
461
462 void CollectedHeap::accumulate_statistics_all_tlabs() {
463 if (UseTLAB) {
464 assert(SafepointSynchronize::is_at_safepoint() ||
465 !is_init_completed(),
466 "should only accumulate statistics on tlabs at safepoint");
467
468 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
469 }
470 }
471
472 void CollectedHeap::resize_all_tlabs() {
473 if (UseTLAB) {
474 assert(SafepointSynchronize::is_at_safepoint() ||
475 !is_init_completed(),
476 "should only resize tlabs at safepoint");
477
478 ThreadLocalAllocBuffer::resize_all_tlabs();
479 }
480 }
481
482 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
483 assert(timer != NULL, "timer is null");
484 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
485 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
486 HeapDumper::dump_heap();
487 }
488
489 LogTarget(Trace, gc, classhisto) lt;
490 if (lt.is_enabled()) {
491 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
492 ResourceMark rm;
493 LogStream ls(lt);
494 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
495 inspector.doit();
496 }
497 }
498
499 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
500 full_gc_dump(timer, true);
501 }
502
503 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
504 full_gc_dump(timer, false);
505 }
506
507 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
508 // It is important to do this in a way such that concurrent readers can't
509 // temporarily think something is in the heap. (Seen this happen in asserts.)
510 _reserved.set_word_size(0);
511 _reserved.set_start(start);
512 _reserved.set_end(end);
513 }
514
515 void CollectedHeap::post_initialize() {
516 initialize_serviceability();
517 }