1 /*
2 * Copyright (c) 2001, 2017, 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/collectedHeap.hpp"
29 #include "gc/shared/collectedHeap.inline.hpp"
30 #include "gc/shared/gcHeapSummary.hpp"
31 #include "gc/shared/gcTrace.hpp"
32 #include "gc/shared/gcTraceTime.inline.hpp"
33 #include "gc/shared/gcWhen.hpp"
34 #include "gc/shared/vmGCOperations.hpp"
35 #include "logging/log.hpp"
36 #include "memory/metaspace.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "oops/instanceMirrorKlass.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/init.hpp"
41 #include "runtime/thread.inline.hpp"
42 #include "services/heapDumper.hpp"
43
44
45 #ifdef ASSERT
46 int CollectedHeap::_fire_out_of_memory_count = 0;
47 #endif
48
49 size_t CollectedHeap::_filler_array_max_size = 0;
50
51 template <>
52 void EventLogBase<GCMessage>::print(outputStream* st, GCMessage& m) {
53 st->print_cr("GC heap %s", m.is_before ? "before" : "after");
54 st->print_raw(m);
55 }
56
57 void GCHeapLog::log_heap(CollectedHeap* heap, bool before) {
58 if (!should_log()) {
59 return;
60 }
61
62 double timestamp = fetch_timestamp();
63 MutexLockerEx ml(&_mutex, Mutex::_no_safepoint_check_flag);
64 int index = compute_log_index();
65 _records[index].thread = NULL; // Its the GC thread so it's not that interesting.
66 _records[index].timestamp = timestamp;
67 _records[index].data.is_before = before;
68 stringStream st(_records[index].data.buffer(), _records[index].data.size());
69
70 st.print_cr("{Heap %s GC invocations=%u (full %u):",
71 before ? "before" : "after",
72 heap->total_collections(),
73 heap->total_full_collections());
74
75 heap->print_on(&st);
76 st.print_cr("}");
77 }
78
79 VirtualSpaceSummary CollectedHeap::create_heap_space_summary() {
80 size_t capacity_in_words = capacity() / HeapWordSize;
81
82 return VirtualSpaceSummary(
83 reserved_region().start(), reserved_region().start() + capacity_in_words, reserved_region().end());
84 }
85
86 GCHeapSummary CollectedHeap::create_heap_summary() {
87 VirtualSpaceSummary heap_space = create_heap_space_summary();
88 return GCHeapSummary(heap_space, used());
89 }
90
91 MetaspaceSummary CollectedHeap::create_metaspace_summary() {
92 const MetaspaceSizes meta_space(
93 MetaspaceAux::committed_bytes(),
94 MetaspaceAux::used_bytes(),
95 MetaspaceAux::reserved_bytes());
96 const MetaspaceSizes data_space(
97 MetaspaceAux::committed_bytes(Metaspace::NonClassType),
98 MetaspaceAux::used_bytes(Metaspace::NonClassType),
99 MetaspaceAux::reserved_bytes(Metaspace::NonClassType));
100 const MetaspaceSizes class_space(
101 MetaspaceAux::committed_bytes(Metaspace::ClassType),
102 MetaspaceAux::used_bytes(Metaspace::ClassType),
103 MetaspaceAux::reserved_bytes(Metaspace::ClassType));
104
105 const MetaspaceChunkFreeListSummary& ms_chunk_free_list_summary =
106 MetaspaceAux::chunk_free_list_summary(Metaspace::NonClassType);
107 const MetaspaceChunkFreeListSummary& class_chunk_free_list_summary =
108 MetaspaceAux::chunk_free_list_summary(Metaspace::ClassType);
109
110 return MetaspaceSummary(MetaspaceGC::capacity_until_GC(), meta_space, data_space, class_space,
111 ms_chunk_free_list_summary, class_chunk_free_list_summary);
112 }
113
114 void CollectedHeap::print_heap_before_gc() {
115 Universe::print_heap_before_gc();
116 if (_gc_heap_log != NULL) {
117 _gc_heap_log->log_heap_before(this);
118 }
119 }
120
121 void CollectedHeap::print_heap_after_gc() {
122 Universe::print_heap_after_gc();
123 if (_gc_heap_log != NULL) {
124 _gc_heap_log->log_heap_after(this);
125 }
126 }
127
128 void CollectedHeap::print_on_error(outputStream* st) const {
129 st->print_cr("Heap:");
130 print_extended_on(st);
131 st->cr();
132
133 _barrier_set->print_on(st);
134 }
135
136 void CollectedHeap::register_nmethod(nmethod* nm) {
137 assert_locked_or_safepoint(CodeCache_lock);
138 if (!nm->on_scavenge_root_list() && nm->detect_scavenge_root_oops()) {
139 CodeCache::add_scavenge_root_nmethod(nm);
140 }
141 }
142
143 void CollectedHeap::unregister_nmethod(nmethod* nm) {
144 assert_locked_or_safepoint(CodeCache_lock);
145 }
146
147 void CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) {
148 const GCHeapSummary& heap_summary = create_heap_summary();
149 gc_tracer->report_gc_heap_summary(when, heap_summary);
150
151 const MetaspaceSummary& metaspace_summary = create_metaspace_summary();
152 gc_tracer->report_metaspace_summary(when, metaspace_summary);
153 }
154
155 void CollectedHeap::trace_heap_before_gc(const GCTracer* gc_tracer) {
156 trace_heap(GCWhen::BeforeGC, gc_tracer);
157 }
158
159 void CollectedHeap::trace_heap_after_gc(const GCTracer* gc_tracer) {
160 trace_heap(GCWhen::AfterGC, gc_tracer);
161 }
162
163 // WhiteBox API support for concurrent collectors. These are the
164 // default implementations, for collectors which don't support this
165 // feature.
166 bool CollectedHeap::supports_concurrent_phase_control() const {
167 return false;
168 }
169
170 const char* const* CollectedHeap::concurrent_phases() const {
171 static const char* const result[] = { NULL };
172 return result;
173 }
174
175 bool CollectedHeap::request_concurrent_phase(const char* phase) {
176 return false;
177 }
178
179 // Memory state functions.
180
181
182 CollectedHeap::CollectedHeap() :
183 _barrier_set(NULL),
184 _is_gc_active(false),
185 _total_collections(0),
186 _total_full_collections(0),
187 _gc_cause(GCCause::_no_gc),
188 _gc_lastcause(GCCause::_no_gc)
189 {
190 const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
191 const size_t elements_per_word = HeapWordSize / sizeof(jint);
192 _filler_array_max_size = align_object_size(filler_array_hdr_size() +
193 max_len / elements_per_word);
194
195 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
196 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
197
198 if (UsePerfData) {
199 EXCEPTION_MARK;
200
201 // create the gc cause jvmstat counters
202 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
203 80, GCCause::to_string(_gc_cause), CHECK);
204
205 _perf_gc_lastcause =
206 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
207 80, GCCause::to_string(_gc_lastcause), CHECK);
208 }
209
210 // Create the ring log
211 if (LogEvents) {
212 _gc_heap_log = new GCHeapLog();
213 } else {
214 _gc_heap_log = NULL;
215 }
216 }
217
218 // This interface assumes that it's being called by the
219 // vm thread. It collects the heap assuming that the
220 // heap lock is already held and that we are executing in
221 // the context of the vm thread.
222 void CollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
223 assert(Thread::current()->is_VM_thread(), "Precondition#1");
224 assert(Heap_lock->is_locked(), "Precondition#2");
225 GCCauseSetter gcs(this, cause);
226 switch (cause) {
227 case GCCause::_heap_inspection:
228 case GCCause::_heap_dump:
229 case GCCause::_metadata_GC_threshold : {
230 HandleMark hm;
231 do_full_collection(false); // don't clear all soft refs
232 break;
233 }
234 case GCCause::_metadata_GC_clear_soft_refs: {
235 HandleMark hm;
236 do_full_collection(true); // do clear all soft refs
237 break;
238 }
239 default:
240 ShouldNotReachHere(); // Unexpected use of this function
241 }
242 }
243
244 void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
245 _barrier_set = barrier_set;
246 oopDesc::set_bs(_barrier_set);
247 }
248
249 void CollectedHeap::pre_initialize() {
250 }
251
252 #ifndef PRODUCT
253 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
254 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
255 for (size_t slot = 0; slot < size; slot += 1) {
256 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
257 "Found badHeapWordValue in post-allocation check");
258 }
259 }
260 }
261
262 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) {
263 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
264 for (size_t slot = 0; slot < size; slot += 1) {
265 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
266 "Found non badHeapWordValue in pre-allocation check");
267 }
268 }
269 }
270 #endif // PRODUCT
271
272 #ifdef ASSERT
273 void CollectedHeap::check_for_valid_allocation_state() {
274 Thread *thread = Thread::current();
275 // How to choose between a pending exception and a potential
276 // OutOfMemoryError? Don't allow pending exceptions.
277 // This is a VM policy failure, so how do we exhaustively test it?
278 assert(!thread->has_pending_exception(),
279 "shouldn't be allocating with pending exception");
280 if (StrictSafepointChecks) {
281 assert(thread->allow_allocation(),
282 "Allocation done by thread for which allocation is blocked "
283 "by No_Allocation_Verifier!");
284 // Allocation of an oop can always invoke a safepoint,
285 // hence, the true argument
286 thread->check_for_valid_safepoint_state(true);
287 }
288 }
289 #endif
290
291 HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, size_t size) {
292
293 // Retain tlab and allocate object in shared space if
294 // the amount free in the tlab is too large to discard.
295 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
296 thread->tlab().record_slow_allocation(size);
297 return NULL;
298 }
299
300 // Discard tlab and allocate a new one.
301 // To minimize fragmentation, the last TLAB may be smaller than the rest.
302 size_t new_tlab_size = thread->tlab().compute_size(size);
303
304 thread->tlab().clear_before_allocation();
305
306 if (new_tlab_size == 0) {
307 return NULL;
308 }
309
310 // Allocate a new TLAB...
311 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
312 if (obj == NULL) {
313 return NULL;
314 }
315
316 AllocTracer::send_allocation_in_new_tlab_event(klass, new_tlab_size * HeapWordSize, size * HeapWordSize);
317
318 if (ZeroTLAB) {
319 // ..and clear it.
320 Copy::zero_to_words(obj, new_tlab_size);
321 } else {
322 // ...and zap just allocated object.
323 #ifdef ASSERT
324 // Skip mangling the space corresponding to the object header to
325 // ensure that the returned space is not considered parsable by
326 // any concurrent GC thread.
327 size_t hdr_size = oopDesc::header_size();
328 Copy::fill_to_words(obj + hdr_size, new_tlab_size - hdr_size, badHeapWordVal);
329 #endif // ASSERT
330 }
331 thread->tlab().fill(obj, obj + size, new_tlab_size);
332 return obj;
333 }
334
335 size_t CollectedHeap::max_tlab_size() const {
336 // TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
337 // This restriction could be removed by enabling filling with multiple arrays.
338 // If we compute that the reasonable way as
339 // header_size + ((sizeof(jint) * max_jint) / HeapWordSize)
340 // we'll overflow on the multiply, so we do the divide first.
341 // We actually lose a little by dividing first,
342 // but that just makes the TLAB somewhat smaller than the biggest array,
343 // which is fine, since we'll be able to fill that.
344 size_t max_int_size = typeArrayOopDesc::header_size(T_INT) +
345 sizeof(jint) *
346 ((juint) max_jint / (size_t) HeapWordSize);
347 return align_size_down(max_int_size, MinObjAlignment);
348 }
349
350 size_t CollectedHeap::filler_array_hdr_size() {
351 return size_t(align_object_offset(arrayOopDesc::header_size(T_INT))); // align to Long
352 }
353
354 size_t CollectedHeap::filler_array_min_size() {
355 return align_object_size(filler_array_hdr_size()); // align to MinObjAlignment
356 }
357
358 #ifdef ASSERT
359 void CollectedHeap::fill_args_check(HeapWord* start, size_t words)
360 {
361 assert(words >= min_fill_size(), "too small to fill");
362 assert(words % MinObjAlignment == 0, "unaligned size");
363 assert(Universe::heap()->is_in_reserved(start), "not in heap");
364 assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
365 }
366
367 void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
368 {
369 if (ZapFillerObjects && zap) {
370 Copy::fill_to_words(start + filler_array_hdr_size(),
371 words - filler_array_hdr_size(), 0XDEAFBABE);
372 }
373 }
374 #endif // ASSERT
375
376 void
377 CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
378 {
379 assert(words >= filler_array_min_size(), "too small for an array");
380 assert(words <= filler_array_max_size(), "too big for a single object");
381
382 const size_t payload_size = words - filler_array_hdr_size();
383 const size_t len = payload_size * HeapWordSize / sizeof(jint);
384 assert((int)len >= 0, "size too large " SIZE_FORMAT " becomes %d", words, (int)len);
385
386 // Set the length first for concurrent GC.
387 ((arrayOop)start)->set_length((int)len);
388 post_allocation_setup_common(Universe::intArrayKlassObj(), start);
389 DEBUG_ONLY(zap_filler_array(start, words, zap);)
390 }
391
392 void
393 CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
394 {
395 assert(words <= filler_array_max_size(), "too big for a single object");
396
397 if (words >= filler_array_min_size()) {
398 fill_with_array(start, words, zap);
399 } else if (words > 0) {
400 assert(words == min_fill_size(), "unaligned size");
401 post_allocation_setup_common(SystemDictionary::Object_klass(), start);
402 }
403 }
404
405 void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
406 {
407 DEBUG_ONLY(fill_args_check(start, words);)
408 HandleMark hm; // Free handles before leaving.
409 fill_with_object_impl(start, words, zap);
410 }
411
412 void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
413 {
414 DEBUG_ONLY(fill_args_check(start, words);)
415 HandleMark hm; // Free handles before leaving.
416
417 // Multiple objects may be required depending on the filler array maximum size. Fill
418 // the range up to that with objects that are filler_array_max_size sized. The
419 // remainder is filled with a single object.
420 const size_t min = min_fill_size();
421 const size_t max = filler_array_max_size();
422 while (words > max) {
423 const size_t cur = (words - max) >= min ? max : max - min;
424 fill_with_array(start, cur, zap);
425 start += cur;
426 words -= cur;
427 }
428
429 fill_with_object_impl(start, words, zap);
430 }
431
432 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
433 guarantee(false, "thread-local allocation buffers not supported");
434 return NULL;
435 }
436
437 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
438 // The second disjunct in the assertion below makes a concession
439 // for the start-up verification done while the VM is being
440 // created. Callers be careful that you know that mutators
441 // aren't going to interfere -- for instance, this is permissible
442 // if we are still single-threaded and have either not yet
443 // started allocating (nothing much to verify) or we have
444 // started allocating but are now a full-fledged JavaThread
445 // (and have thus made our TLAB's) available for filling.
446 assert(SafepointSynchronize::is_at_safepoint() ||
447 !is_init_completed(),
448 "Should only be called at a safepoint or at start-up"
449 " otherwise concurrent mutator activity may make heap "
450 " unparsable again");
451 const bool use_tlab = UseTLAB;
452 // The main thread starts allocating via a TLAB even before it
453 // has added itself to the threads list at vm boot-up.
454 assert(!use_tlab || Threads::first() != NULL,
455 "Attempt to fill tlabs before main thread has been added"
456 " to threads list is doomed to failure!");
457 BarrierSet *bs = barrier_set();
458 for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
459 if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
460 bs->make_parsable(thread);
461 }
462 }
463
464 void CollectedHeap::accumulate_statistics_all_tlabs() {
465 if (UseTLAB) {
466 assert(SafepointSynchronize::is_at_safepoint() ||
467 !is_init_completed(),
468 "should only accumulate statistics on tlabs at safepoint");
469
470 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
471 }
472 }
473
474 void CollectedHeap::resize_all_tlabs() {
475 if (UseTLAB) {
476 assert(SafepointSynchronize::is_at_safepoint() ||
477 !is_init_completed(),
478 "should only resize tlabs at safepoint");
479
480 ThreadLocalAllocBuffer::resize_all_tlabs();
481 }
482 }
483
484 void CollectedHeap::full_gc_dump(GCTimer* timer, bool before) {
485 assert(timer != NULL, "timer is null");
486 if ((HeapDumpBeforeFullGC && before) || (HeapDumpAfterFullGC && !before)) {
487 GCTraceTime(Info, gc) tm(before ? "Heap Dump (before full gc)" : "Heap Dump (after full gc)", timer);
488 HeapDumper::dump_heap();
489 }
490
491 Log(gc, classhisto) log;
492 if (log.is_trace()) {
493 GCTraceTime(Trace, gc, classhisto) tm(before ? "Class Histogram (before full gc)" : "Class Histogram (after full gc)", timer);
494 ResourceMark rm;
495 VM_GC_HeapInspection inspector(log.trace_stream(), false /* ! full gc */);
496 inspector.doit();
497 }
498 }
499
500 void CollectedHeap::pre_full_gc_dump(GCTimer* timer) {
501 full_gc_dump(timer, true);
502 }
503
504 void CollectedHeap::post_full_gc_dump(GCTimer* timer) {
505 full_gc_dump(timer, false);
506 }
507
508 void CollectedHeap::initialize_reserved_region(HeapWord *start, HeapWord *end) {
509 // It is important to do this in a way such that concurrent readers can't
510 // temporarily think something is in the heap. (Seen this happen in asserts.)
511 _reserved.set_word_size(0);
512 _reserved.set_start(start);
513 _reserved.set_end(end);
514 }
515
516 void CollectedHeap::verify_nmethod_roots(nmethod* nmethod) {
517 nmethod->verify_scavenge_root_oops();
518 }