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