1 /*
2 * Copyright (c) 1997, 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 "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 "oops/typeArrayOop.inline.hpp"
41 #include "utilities/macros.hpp"
42 #include "utilities/stack.inline.hpp"
43
44 uint MarkSweep::_total_invocations = 0;
45
46 Stack<oop, mtGC> MarkSweep::_marking_stack;
47 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
48
49 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack;
50 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack;
51 size_t MarkSweep::_preserved_count = 0;
52 size_t MarkSweep::_preserved_count_max = 0;
53 PreservedMark* MarkSweep::_preserved_marks = NULL;
54 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
55 STWGCTimer* MarkSweep::_gc_timer = NULL;
56 SerialOldTracer* MarkSweep::_gc_tracer = NULL;
57
58 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
59
60 MarkAndPushClosure MarkSweep::mark_and_push_closure;
61 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure);
62 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure);
63
64 inline void MarkSweep::mark_object(oop obj) {
65 // some marks may contain information we need to preserve so we store them away
66 // and overwrite the mark. We'll restore it at the end of markSweep.
67 markOop mark = obj->mark_raw();
68 obj->set_mark_raw(markOopDesc::prototype()->set_marked());
69
70 if (mark->must_be_preserved(obj)) {
71 preserve_mark(obj, mark);
72 }
73 }
74
75 template <class T> inline void MarkSweep::mark_and_push(T* p) {
76 T heap_oop = oopDesc::load_heap_oop(p);
77 if (!oopDesc::is_null(heap_oop)) {
78 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
79 if (!obj->mark_raw()->is_marked()) {
80 mark_object(obj);
81 _marking_stack.push(obj);
82 }
83 }
84 }
85
86 inline void MarkSweep::follow_klass(Klass* klass) {
87 oop op = klass->klass_holder();
88 MarkSweep::mark_and_push(&op);
89 }
90
91 inline void MarkSweep::follow_cld(ClassLoaderData* cld) {
92 MarkSweep::follow_cld_closure.do_cld(cld);
93 }
94
95 template <typename T>
96 inline void MarkAndPushClosure::do_oop_nv(T* p) { MarkSweep::mark_and_push(p); }
97 void MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); }
98 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
99 inline bool MarkAndPushClosure::do_metadata_nv() { return true; }
100 bool MarkAndPushClosure::do_metadata() { return do_metadata_nv(); }
101 inline void MarkAndPushClosure::do_klass_nv(Klass* k) { MarkSweep::follow_klass(k); }
102 void MarkAndPushClosure::do_klass(Klass* k) { do_klass_nv(k); }
103 inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); }
104 void MarkAndPushClosure::do_cld(ClassLoaderData* cld) { do_cld_nv(cld); }
105
106 template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
107 mark_and_push(p);
108 }
109
110 void MarkSweep::push_objarray(oop obj, size_t index) {
111 ObjArrayTask task(obj, index);
112 assert(task.is_valid(), "bad ObjArrayTask");
113 _objarray_stack.push(task);
114 }
115
116 inline void MarkSweep::follow_array(objArrayOop array) {
117 MarkSweep::follow_klass(array->klass());
118 // Don't push empty arrays to avoid unnecessary work.
119 if (array->length() > 0) {
120 MarkSweep::push_objarray(array, 0);
121 }
122 }
123
124 inline void MarkSweep::follow_object(oop obj) {
125 assert(obj->is_gc_marked(), "should be marked");
126 if (obj->is_objArray()) {
127 // Handle object arrays explicitly to allow them to
128 // be split into chunks if needed.
129 MarkSweep::follow_array((objArrayOop)obj);
130 } else {
131 obj->oop_iterate(&mark_and_push_closure);
132 }
133 }
134
135 void MarkSweep::follow_array_chunk(objArrayOop array, int index) {
136 const int len = array->length();
137 const int beg_index = index;
138 assert(beg_index < len || len == 0, "index too large");
139
140 const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride);
141 const int end_index = beg_index + stride;
142
143 array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index);
144
145 if (end_index < len) {
146 MarkSweep::push_objarray(array, end_index); // Push the continuation.
147 }
148 }
149
150 void MarkSweep::follow_stack() {
151 do {
152 while (!_marking_stack.is_empty()) {
153 oop obj = _marking_stack.pop();
154 assert (obj->is_gc_marked(), "p must be marked");
155 follow_object(obj);
156 }
157 // Process ObjArrays one at a time to avoid marking stack bloat.
158 if (!_objarray_stack.is_empty()) {
159 ObjArrayTask task = _objarray_stack.pop();
160 follow_array_chunk(objArrayOop(task.obj()), task.index());
161 }
162 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
163 }
164
165 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
166
167 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
168
169 template <class T> inline void MarkSweep::follow_root(T* p) {
170 assert(!Universe::heap()->is_in_reserved(p),
171 "roots shouldn't be things within the heap");
172 T heap_oop = oopDesc::load_heap_oop(p);
173 if (!oopDesc::is_null(heap_oop)) {
174 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
175 if (!obj->mark_raw()->is_marked()) {
176 mark_object(obj);
177 follow_object(obj);
178 }
179 }
180 follow_stack();
181 }
182
183 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
184 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
185
186 void PreservedMark::adjust_pointer() {
187 MarkSweep::adjust_pointer(&_obj);
188 }
189
190 void PreservedMark::restore() {
191 _obj->set_mark_raw(_mark);
192 }
193
194 // We preserve the mark which should be replaced at the end and the location
195 // that it will go. Note that the object that this markOop belongs to isn't
196 // currently at that address but it will be after phase4
197 void MarkSweep::preserve_mark(oop obj, markOop mark) {
198 // We try to store preserved marks in the to space of the new generation since
199 // this is storage which should be available. Most of the time this should be
200 // sufficient space for the marks we need to preserve but if it isn't we fall
201 // back to using Stacks to keep track of the overflow.
202 if (_preserved_count < _preserved_count_max) {
203 _preserved_marks[_preserved_count++].init(obj, mark);
204 } else {
205 _preserved_mark_stack.push(mark);
206 _preserved_oop_stack.push(obj);
207 }
208 }
209
210 void MarkSweep::set_ref_processor(ReferenceProcessor* rp) {
211 _ref_processor = rp;
212 mark_and_push_closure.set_ref_processor(_ref_processor);
213 }
214
215 AdjustPointerClosure MarkSweep::adjust_pointer_closure;
216
217 template <typename T>
218 void AdjustPointerClosure::do_oop_nv(T* p) { MarkSweep::adjust_pointer(p); }
219 void AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); }
220 void AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
221
222 void MarkSweep::adjust_marks() {
223 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
224 "inconsistent preserved oop stacks");
225
226 // adjust the oops we saved earlier
227 for (size_t i = 0; i < _preserved_count; i++) {
228 _preserved_marks[i].adjust_pointer();
229 }
230
231 // deal with the overflow stack
232 StackIterator<oop, mtGC> iter(_preserved_oop_stack);
233 while (!iter.is_empty()) {
234 oop* p = iter.next_addr();
235 adjust_pointer(p);
236 }
237 }
238
239 void MarkSweep::restore_marks() {
240 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
241 "inconsistent preserved oop stacks");
242 log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_oop_stack.size());
243
244 // restore the marks we saved earlier
245 for (size_t i = 0; i < _preserved_count; i++) {
246 _preserved_marks[i].restore();
247 }
248
249 // deal with the overflow
250 while (!_preserved_oop_stack.is_empty()) {
251 oop obj = _preserved_oop_stack.pop();
252 markOop mark = _preserved_mark_stack.pop();
253 obj->set_mark_raw(mark);
254 }
255 }
256
257 MarkSweep::IsAliveClosure MarkSweep::is_alive;
258
259 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
260
261 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
262
263 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
264 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
265
266 void marksweep_init() {
267 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
268 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();
269 }
270
271 // Generate MS specialized oop_oop_iterate functions.
272 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)