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