1 /*
2 * Copyright (c) 1997, 2015, 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 "compiler/compileBroker.hpp"
27 #include "gc/serial/markSweep.inline.hpp"
28 #include "gc/shared/collectedHeap.inline.hpp"
29 #include "gc/shared/gcTimer.hpp"
30 #include "gc/shared/gcTrace.hpp"
31 #include "gc/shared/specialized_oop_closures.hpp"
32 #include "memory/iterator.inline.hpp"
33 #include "oops/instanceClassLoaderKlass.inline.hpp"
34 #include "oops/instanceKlass.inline.hpp"
35 #include "oops/instanceMirrorKlass.inline.hpp"
36 #include "oops/instanceRefKlass.inline.hpp"
37 #include "oops/methodData.hpp"
38 #include "oops/objArrayKlass.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "utilities/macros.hpp"
41 #include "utilities/stack.inline.hpp"
42 #if INCLUDE_ALL_GCS
43 #include "gc/g1/g1StringDedup.hpp"
44 #endif // INCLUDE_ALL_GCS
45
46 uint MarkSweep::_total_invocations = 0;
47
48 Stack<oop, mtGC> MarkSweep::_marking_stack;
49 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
50
51 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack;
52 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack;
53 size_t MarkSweep::_preserved_count = 0;
54 size_t MarkSweep::_preserved_count_max = 0;
55 PreservedMark* MarkSweep::_preserved_marks = NULL;
56 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
57 STWGCTimer* MarkSweep::_gc_timer = NULL;
58 SerialOldTracer* MarkSweep::_gc_tracer = NULL;
59
60 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
61
62 MarkAndPushClosure MarkSweep::mark_and_push_closure;
63 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure);
64 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure);
65
66 inline void MarkSweep::mark_object(oop obj) {
67 #if INCLUDE_ALL_GCS
68 if (G1StringDedup::is_enabled()) {
69 // We must enqueue the object before it is marked
70 // as we otherwise can't read the object's age.
71 G1StringDedup::enqueue_from_mark(obj);
72 }
73 #endif
74 // some marks may contain information we need to preserve so we store them away
75 // and overwrite the mark. We'll restore it at the end of markSweep.
76 markOop mark = obj->mark();
77 obj->set_mark(markOopDesc::prototype()->set_marked());
78
79 if (mark->must_be_preserved(obj)) {
80 preserve_mark(obj, mark);
81 }
82 }
83
84 template <class T> inline void MarkSweep::mark_and_push(T* p) {
85 T heap_oop = oopDesc::load_heap_oop(p);
86 if (!oopDesc::is_null(heap_oop)) {
87 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
88 if (UseShenandoahGC) {
89 obj = ShenandoahBarrierSet::resolve_and_update_oop_static(p, obj);
90 }
91 if (!obj->mark()->is_marked() &&
92 !is_archive_object(obj)) {
93 mark_object(obj);
94 _marking_stack.push(obj);
95 }
96 }
97 }
98
99 inline void MarkSweep::follow_klass(Klass* klass) {
100 oop op = klass->klass_holder();
101 MarkSweep::mark_and_push(&op);
102 }
103
104 inline void MarkSweep::follow_cld(ClassLoaderData* cld) {
105 MarkSweep::follow_cld_closure.do_cld(cld);
106 }
107
108 template <typename T>
109 inline void MarkAndPushClosure::do_oop_nv(T* p) { MarkSweep::mark_and_push(p); }
110 void MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); }
111 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
112 inline bool MarkAndPushClosure::do_metadata_nv() { return true; }
113 bool MarkAndPushClosure::do_metadata() { return do_metadata_nv(); }
114 inline void MarkAndPushClosure::do_klass_nv(Klass* k) { MarkSweep::follow_klass(k); }
115 void MarkAndPushClosure::do_klass(Klass* k) { do_klass_nv(k); }
116 inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); }
117 void MarkAndPushClosure::do_cld(ClassLoaderData* cld) { do_cld_nv(cld); }
118
119 template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
120 mark_and_push(p);
121 }
122
123 void MarkSweep::push_objarray(oop obj, size_t index) {
124 ObjArrayTask task(obj, index);
125 assert(task.is_valid(), "bad ObjArrayTask");
126 _objarray_stack.push(task);
127 }
128
129 inline void MarkSweep::follow_array(objArrayOop array) {
130 MarkSweep::follow_klass(array->klass());
131 // Don't push empty arrays to avoid unnecessary work.
132 if (array->length() > 0) {
133 MarkSweep::push_objarray(array, 0);
134 }
135 }
136
137 inline void MarkSweep::follow_object(oop obj) {
138 assert(obj->is_gc_marked(), "should be marked");
139 if (obj->is_objArray()) {
140 // Handle object arrays explicitly to allow them to
141 // be split into chunks if needed.
142 MarkSweep::follow_array((objArrayOop)obj);
143 } else {
144 obj->oop_iterate(&mark_and_push_closure);
145 }
146 }
147
148 void MarkSweep::follow_array_chunk(objArrayOop array, int index) {
149 const int len = array->length();
150 const int beg_index = index;
151 assert(beg_index < len || len == 0, "index too large");
152
153 const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride);
154 const int end_index = beg_index + stride;
155
156 array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index);
157
158 if (end_index < len) {
159 MarkSweep::push_objarray(array, end_index); // Push the continuation.
160 }
161 }
162
163 void MarkSweep::follow_stack() {
164 do {
165 while (!_marking_stack.is_empty()) {
166 oop obj = _marking_stack.pop();
167 assert (obj->is_gc_marked(), "p must be marked");
168 follow_object(obj);
169 }
170 // Process ObjArrays one at a time to avoid marking stack bloat.
171 if (!_objarray_stack.is_empty()) {
172 ObjArrayTask task = _objarray_stack.pop();
173 follow_array_chunk(objArrayOop(task.obj()), task.index());
174 }
175 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
176 }
177
178 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
179
180 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
181
182 template <class T> inline void MarkSweep::follow_root(T* p) {
183 assert(!Universe::heap()->is_in_reserved(p),
184 "roots shouldn't be things within the heap");
185 T heap_oop = oopDesc::load_heap_oop(p);
186 if (!oopDesc::is_null(heap_oop)) {
187 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
188 if (UseShenandoahGC) {
189 obj = ShenandoahBarrierSet::resolve_and_update_oop_static(p, obj);
190 }
191 if (!obj->mark()->is_marked() &&
192 !is_archive_object(obj)) {
193 mark_object(obj);
194 follow_object(obj);
195 }
196 }
197 follow_stack();
198 }
199
200 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
201 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
202
203 void PreservedMark::adjust_pointer() {
204 MarkSweep::adjust_pointer(&_obj);
205 }
206
207 void PreservedMark::restore() {
208 _obj->set_mark(_mark);
209 }
210
211 // We preserve the mark which should be replaced at the end and the location
212 // that it will go. Note that the object that this markOop belongs to isn't
213 // currently at that address but it will be after phase4
214 void MarkSweep::preserve_mark(oop obj, markOop mark) {
215 // We try to store preserved marks in the to space of the new generation since
216 // this is storage which should be available. Most of the time this should be
217 // sufficient space for the marks we need to preserve but if it isn't we fall
218 // back to using Stacks to keep track of the overflow.
219 if (_preserved_count < _preserved_count_max) {
220 _preserved_marks[_preserved_count++].init(obj, mark);
221 } else {
222 _preserved_mark_stack.push(mark);
223 _preserved_oop_stack.push(obj);
224 }
225 }
226
227 void MarkSweep::set_ref_processor(ReferenceProcessor* rp) {
228 _ref_processor = rp;
229 mark_and_push_closure.set_ref_processor(_ref_processor);
230 }
231
232 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure;
233
234 template <typename T>
235 void MarkSweep::AdjustPointerClosure::do_oop_nv(T* p) { adjust_pointer(p); }
236 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); }
237 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
238
239 void MarkSweep::adjust_marks() {
240 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
241 "inconsistent preserved oop stacks");
242
243 // adjust the oops we saved earlier
244 for (size_t i = 0; i < _preserved_count; i++) {
245 _preserved_marks[i].adjust_pointer();
246 }
247
248 // deal with the overflow stack
249 StackIterator<oop, mtGC> iter(_preserved_oop_stack);
250 while (!iter.is_empty()) {
251 oop* p = iter.next_addr();
252 adjust_pointer(p);
253 }
254 }
255
256 void MarkSweep::restore_marks() {
257 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
258 "inconsistent preserved oop stacks");
259 if (PrintGC && Verbose) {
260 gclog_or_tty->print_cr("Restoring " SIZE_FORMAT " marks",
261 _preserved_count + _preserved_oop_stack.size());
262 }
263
264 // restore the marks we saved earlier
265 for (size_t i = 0; i < _preserved_count; i++) {
266 _preserved_marks[i].restore();
267 }
268
269 // deal with the overflow
270 while (!_preserved_oop_stack.is_empty()) {
271 oop obj = _preserved_oop_stack.pop();
272 markOop mark = _preserved_mark_stack.pop();
273 obj->set_mark(mark);
274 }
275 }
276
277 MarkSweep::IsAliveClosure MarkSweep::is_alive;
278
279 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked() || is_archive_object(p); }
280
281 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
282
283 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
284 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
285
286 void marksweep_init() {
287 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
288 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();
289 }
290
291 int InstanceKlass::oop_ms_adjust_pointers(oop obj) {
292 int size = size_helper();
293 oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::adjust_pointer_closure);
294 return size;
295 }
296
297 int InstanceMirrorKlass::oop_ms_adjust_pointers(oop obj) {
298 int size = oop_size(obj);
299 InstanceKlass::oop_ms_adjust_pointers(obj);
300
301 oop_oop_iterate_statics<true>(obj, &MarkSweep::adjust_pointer_closure);
302 return size;
303 }
304
305 int InstanceClassLoaderKlass::oop_ms_adjust_pointers(oop obj) {
306 return InstanceKlass::oop_ms_adjust_pointers(obj);
307 }
308
309 #ifdef ASSERT
310 template <class T> static void trace_reference_gc(const char *s, oop obj,
311 T* referent_addr,
312 T* next_addr,
313 T* discovered_addr) {
314 if(TraceReferenceGC && PrintGCDetails) {
315 gclog_or_tty->print_cr("%s obj " PTR_FORMAT, s, p2i(obj));
316 gclog_or_tty->print_cr(" referent_addr/* " PTR_FORMAT " / "
317 PTR_FORMAT, p2i(referent_addr),
318 p2i(referent_addr ?
319 (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL));
320 gclog_or_tty->print_cr(" next_addr/* " PTR_FORMAT " / "
321 PTR_FORMAT, p2i(next_addr),
322 p2i(next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL));
323 gclog_or_tty->print_cr(" discovered_addr/* " PTR_FORMAT " / "
324 PTR_FORMAT, p2i(discovered_addr),
325 p2i(discovered_addr ?
326 (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL));
327 }
328 }
329 #endif
330
331 template <class T> void static adjust_object_specialized(oop obj) {
332 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
333 MarkSweep::adjust_pointer(referent_addr);
334 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
335 MarkSweep::adjust_pointer(next_addr);
336 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
337 MarkSweep::adjust_pointer(discovered_addr);
338 debug_only(trace_reference_gc("InstanceRefKlass::oop_ms_adjust_pointers", obj,
339 referent_addr, next_addr, discovered_addr);)
340 }
341
342 int InstanceRefKlass::oop_ms_adjust_pointers(oop obj) {
343 int size = size_helper();
344 InstanceKlass::oop_ms_adjust_pointers(obj);
345
346 if (UseCompressedOops) {
347 adjust_object_specialized<narrowOop>(obj);
348 } else {
349 adjust_object_specialized<oop>(obj);
350 }
351 return size;
352 }
353
354 int ObjArrayKlass::oop_ms_adjust_pointers(oop obj) {
355 assert(obj->is_objArray(), "obj must be obj array");
356 objArrayOop a = objArrayOop(obj);
357 // Get size before changing pointers.
358 // Don't call size() or oop_size() since that is a virtual call.
359 int size = a->object_size();
360 oop_oop_iterate_elements<true>(a, &MarkSweep::adjust_pointer_closure);
361 return size;
362 }
363
364 int TypeArrayKlass::oop_ms_adjust_pointers(oop obj) {
365 assert(obj->is_typeArray(), "must be a type array");
366 typeArrayOop t = typeArrayOop(obj);
367 // Performance tweak: We skip iterating over the klass pointer since we
368 // know that Universe::TypeArrayKlass never moves.
369 return t->object_size();
370 }
371
372 // Generate MS specialized oop_oop_iterate functions.
373 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)