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.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/collectedHeap.inline.hpp"
31 #include "gc/shared/fill.hpp"
32 #include "gc/shared/gcLocker.inline.hpp"
33 #include "gc/shared/gcHeapSummary.hpp"
34 #include "gc/shared/gcTrace.hpp"
35 #include "gc/shared/gcTraceTime.inline.hpp"
36 #include "gc/shared/gcWhen.hpp"
37 #include "gc/shared/memAllocator.hpp"
38 #include "gc/shared/vmGCOperations.hpp"
39 #include "logging/log.hpp"
40 #include "memory/metaspace.hpp"
41 #include "memory/resourceArea.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 #ifdef ASSERT
56 int CollectedHeap::_fire_out_of_memory_count = 0;
57 #endif
58
59 template <>
60 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
61 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
62 st->print_raw(m);
63 }
64
65 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
66 if (!should_log()) {
67 return;
68 }
69
70 double timestamp = fetch_timestamp();
71 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
72 int index = compute_log_index();
73 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
74 _records[index].timestamp = timestamp;
75 _records[index].data.is_before = before;
76 stringStream st(_records[index].data.buffer(), _records[index].data.size());
77
78 st.print_cr("{Heap %s GC invocations=%u (full %u):",
79 before ? "before" : "after",
80 heap->total_collections(),
81 heap->total_full_collections());
82
83 heap->print_on(&st);
84 st.print_cr("}");
85 }
86
87 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
88 size_t capacity_in_words = capacity() / HeapWordSize;
89
90 return VirtualSpaceSummary(
91 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
92 }
93
94 GCHeapSummary CollectedHeap::create_heap_summary() {
95 VirtualSpaceSummary heap_space = create_heap_space_summary();
96 return GCHeapSummary(heap_space, used());
97 }
98
99 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
100 const MetaspaceSizes meta_space(
101 MetaspaceUtils::committed_bytes(),
102 MetaspaceUtils::used_bytes(),
103 MetaspaceUtils::reserved_bytes());
104 const MetaspaceSizes data_space(
105 MetaspaceUtils::committed_bytes(Metaspace::NonClassType),
106 MetaspaceUtils::used_bytes(Metaspace::NonClassType),
107 MetaspaceUtils::reserved_bytes(Metaspace::NonClassType));
108 const MetaspaceSizes class_space(
109 MetaspaceUtils::committed_bytes(Metaspace::ClassType),
110 MetaspaceUtils::used_bytes(Metaspace::ClassType),
111 MetaspaceUtils::reserved_bytes(Metaspace::ClassType));
112
113 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
114 MetaspaceUtils::chunk_free_list_summary(Metaspace::NonClassType);
115 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
116 MetaspaceUtils::chunk_free_list_summary(Metaspace::ClassType);
117
118 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
119 ms_chunk_free_list_summary, class_chunk_free_list_summary);
120 }
121
122 void CollectedHeap::print_heap_before_gc() {
123 Universe::print_heap_before_gc();
124 if (_gc_heap_log != NULL) {
125 _gc_heap_log->log_heap_before(this);
126 }
127 }
128
129 void CollectedHeap::print_heap_after_gc() {
130 Universe::print_heap_after_gc();
131 if (_gc_heap_log != NULL) {
132 _gc_heap_log->log_heap_after(this);
133 }
134 }
135
136 void CollectedHeap::print_on_error(outputStream* st) const {
137 st->print_cr("Heap:");
138 print_extended_on(st);
139 st->cr();
140
141 BarrierSet::barrier_set()->print_on(st);
142 }
143
144 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
145 const GCHeapSummary& heap_summary = create_heap_summary();
146 gc_tracer->report_gc_heap_summary(when, heap_summary);
147
148 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
149 gc_tracer->report_metaspace_summary(when, metaspace_summary);
150 }
151
152 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
153 trace_heap(GCWhen::BeforeGC, gc_tracer);
154 }
155
156 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
157 trace_heap(GCWhen::AfterGC, gc_tracer);
158 }
159
160 // WhiteBox API support for concurrent collectors. These are the
161 // default implementations, for collectors which don't support this
162 // feature.
163 bool CollectedHeap::supports_concurrent_phase_control() const {
164 return false;
165 }
166
167 const char* const* CollectedHeap::concurrent_phases() const {
168 static const char* const result[] = { NULL };
169 return result;
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 (!check_obj_alignment(object)) {
178 return false;
179 }
180
181 if (!is_in_reserved(object)) {
182 return false;
183 }
184
185 if (is_in_reserved(object->klass_or_null())) {
186 return false;
187 }
188
189 return true;
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 Fill::initialize();
200
201 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
202 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
203
204 if (UsePerfData) {
205 EXCEPTION_MARK;
206
207 // create the gc cause jvmstat counters
208 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
209 80, GCCause::to_string(_gc_cause), CHECK);
210
211 _perf_gc_lastcause =
212 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
213 80, GCCause::to_string(_gc_lastcause), CHECK);
214 }
215
216 // Create the ring log
217 if (LogEvents) {
218 _gc_heap_log = new GCHeapLog();
219 } else {
220 _gc_heap_log = NULL;
221 }
222 }
223
224 // This interface assumes that it's being called by the
225 // vm thread. It collects the heap assuming that the
226 // heap lock is already held and that we are executing in
227 // the context of the vm thread.
228 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
229 assert(Thread::current()->is_VM_thread(), "Precondition#1");
230 assert(Heap_lock->is_locked(), "Precondition#2");
231 GCCauseSetter gcs(this, cause);
232 switch (cause) {
233 case GCCause::_heap_inspection:
234 case GCCause::_heap_dump:
235 case GCCause::_metadata_GC_threshold : {
236 HandleMark hm;
237 do_full_collection(false); // don't clear all soft refs
238 break;
239 }
240 case GCCause::_metadata_GC_clear_soft_refs: {
241 HandleMark hm;
242 do_full_collection(true); // do clear all soft refs
243 break;
244 }
245 default:
246 ShouldNotReachHere(); // Unexpected use of this function
247 }
248 }
249
250 MetaWord* CollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
251 size_t word_size,
252 Metaspace::MetadataType mdtype) {
253 uint loop_count = 0;
254 uint gc_count = 0;
255 uint full_gc_count = 0;
256
257 assert(!Heap_lock->owned_by_self(), "Should not be holding the Heap_lock");
258
259 do {
260 MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
261 if (result != NULL) {
262 return result;
263 }
264
265 if (GCLocker::is_active_and_needs_gc()) {
266 // If the GCLocker is active, just expand and allocate.
267 // If that does not succeed, wait if this thread is not
268 // in a critical section itself.
269 result = loader_data->metaspace_non_null()->expand_and_allocate(word_size, mdtype);
270 if (result != NULL) {
271 return result;
272 }
273 JavaThread* jthr = JavaThread::current();
274 if (!jthr->in_critical()) {
275 // Wait for JNI critical section to be exited
276 GCLocker::stall_until_clear();
277 // The GC invoked by the last thread leaving the critical
278 // section will be a young collection and a full collection
279 // is (currently) needed for unloading classes so continue
280 // to the next iteration to get a full GC.
281 continue;
282 } else {
283 if (CheckJNICalls) {
284 fatal("Possible deadlock due to allocating while"
285 " in jni critical section");
286 }
287 return NULL;
288 }
289 }
290
291 { // Need lock to get self consistent gc_count's
292 MutexLocker ml(Heap_lock);
293 gc_count = Universe::heap()->total_collections();
294 full_gc_count = Universe::heap()->total_full_collections();
295 }
296
297 // Generate a VM operation
298 VM_CollectForMetadataAllocation op(loader_data,
299 word_size,
300 mdtype,
301 gc_count,
302 full_gc_count,
303 GCCause::_metadata_GC_threshold);
304 VMThread::execute(&op);
305
306 // If GC was locked out, try again. Check before checking success because the
307 // prologue could have succeeded and the GC still have been locked out.
308 if (op.gc_locked()) {
309 continue;
310 }
311
312 if (op.prologue_succeeded()) {
313 return op.result();
314 }
315 loop_count++;
316 if ((QueuedAllocationWarningCount > 0) &&
317 (loop_count % QueuedAllocationWarningCount == 0)) {
318 log_warning(gc, ergo)("satisfy_failed_metadata_allocation() retries %d times,"
319 " size=" SIZE_FORMAT, loop_count, word_size);
320 }
321 } while (true); // Until a GC is done
322 }
323
324 MemoryUsage CollectedHeap::memory_usage() {
325 return MemoryUsage(InitialHeapSize, used(), capacity(), max_capacity());
326 }
327
328
329 #ifndef PRODUCT
330 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
331 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
332 for (size_t slot = 0; slot < size; slot += 1) {
333 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
334 "Found non badHeapWordValue in pre-allocation check");
335 }
336 }
337 }
338 #endif // PRODUCT
339
340 size_t CollectedHeap::max_tlab_size() const {
341 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
342 // This restriction could be removed by enabling filling with multiple arrays.
343 // If we compute that the reasonable way as
344 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
345 // we'll overflow on the multiply, so we do the divide first.
346 // We actually lose a little by dividing first,
347 // but that just makes the TLAB somewhat smaller than the biggest array,
348 // which is fine, since we'll be able to fill that.
349 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
350 sizeof(jint) *
351 ((juint) max_jint / (size_t) HeapWordSize);
352 return align_down(max_int_size, MinObjAlignment);
353 }
354
355 HeapWord* CollectedHeap::allocate_new_tlab(size_t min_size,
356 size_t requested_size,
357 size_t* actual_size) {
358 guarantee(false, "thread-local allocation buffers not supported");
359 return NULL;
360 }
361
362 oop CollectedHeap::obj_allocate(Klass* klass, int size, TRAPS) {
363 ObjAllocator allocator(klass, size, THREAD);
364 return allocator.allocate();
365 }
366
367 oop CollectedHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
368 ObjArrayAllocator allocator(klass, size, length, do_zero, THREAD);
369 return allocator.allocate();
370 }
371
372 oop CollectedHeap::class_allocate(Klass* klass, int size, TRAPS) {
373 ClassAllocator allocator(klass, size, THREAD);
374 return allocator.allocate();
375 }
376
377 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
378 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
379 "Should only be called at a safepoint or at start-up");
380
381 ThreadLocalAllocStats stats;
382
383 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next();) {
384 BarrierSet::barrier_set()->make_parsable(thread);
385 if (UseTLAB) {
386 if (retire_tlabs) {
387 thread->tlab().retire(&stats);
388 } else {
389 thread->tlab().make_parsable();
390 }
391 }
392 }
393
394 stats.publish();
395 }
396
397 void CollectedHeap::resize_all_tlabs() {
398 assert(SafepointSynchronize::is_at_safepoint() || !is_init_completed(),
399 "Should only resize tlabs at safepoint");
400
401 if (UseTLAB && ResizeTLAB) {
402 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
403 thread->tlab().resize();
404 }
405 }
406 }
407
408 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
409 assert(timer != NULL, "timer is null");
410 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
411 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
412 HeapDumper::dump_heap();
413 }
414
415 LogTarget(Trace, gc, classhisto) lt;
416 if (lt.is_enabled()) {
417 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
418 ResourceMark rm;
419 LogStream ls(lt);
420 VM_GC_HeapInspection inspector(&ls, false /* ! full gc */);
421 inspector.doit();
422 }
423 }
424
425 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
426 full_gc_dump(timer, true);
427 }
428
429 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
430 full_gc_dump(timer, false);
431 }
432
433 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
434 // It is important to do this in a way such that concurrent readers can't
435 // temporarily think something is in the heap. (Seen this happen in asserts.)
436 _reserved.set_word_size(0);
437 _reserved.set_start(start);
438 _reserved.set_end(end);
439 }
440
441 void CollectedHeap::post_initialize() {
442 initialize_serviceability();
443 }
444
445 #ifndef PRODUCT
446
447 bool CollectedHeap::promotion_should_fail(volatile size_t* count) {
448 // Access to count is not atomic; the value does not have to be exact.
449 if (PromotionFailureALot) {
450 const size_t gc_num = total_collections();
451 const size_t elapsed_gcs = gc_num - _promotion_failure_alot_gc_number;
452 if (elapsed_gcs >= PromotionFailureALotInterval) {
453 // Test for unsigned arithmetic wrap-around.
454 if (++*count >= PromotionFailureALotCount) {
455 *count = 0;
456 return true;
457 }
458 }
459 }
460 return false;
461 }
462
463 bool CollectedHeap::promotion_should_fail() {
464 return promotion_should_fail(&_promotion_failure_alot_count);
465 }
466
467 void CollectedHeap::reset_promotion_should_fail(volatile size_t* count) {
468 if (PromotionFailureALot) {
469 _promotion_failure_alot_gc_number = total_collections();
470 *count = 0;
471 }
472 }
473
474 void CollectedHeap::reset_promotion_should_fail() {
475 reset_promotion_should_fail(&_promotion_failure_alot_count);
476 }
477
478 #endif // #ifndef PRODUCT
479
480 bool CollectedHeap::supports_object_pinning() const {
481 return false;
482 }
483
484 oop CollectedHeap::pin_object(JavaThread* thread, oop obj) {
485 ShouldNotReachHere();
486 return NULL;
487 }
488
489 void CollectedHeap::unpin_object(JavaThread* thread, oop obj) {
490 ShouldNotReachHere();
491 }
492
493 void CollectedHeap::deduplicate_string(oop str) {
494 // Do nothing, unless overridden in subclass.
495 }
496
497 size_t CollectedHeap::obj_size(oop obj) const {
498 return obj->size();
499 }