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