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_implementation/shared/gcTimer.hpp"
28 #include "gc_implementation/shared/gcTrace.hpp"
29 #include "gc_implementation/shared/markSweep.inline.hpp"
30 #include "gc_interface/collectedHeap.inline.hpp"
31 #include "oops/methodData.hpp"
32 #include "oops/objArrayKlass.inline.hpp"
33 #include "oops/oop.inline.hpp"
34
35 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
36
37 uint MarkSweep::_total_invocations = 0;
38
39 Stack<oop, mtGC> MarkSweep::_marking_stack;
40 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
41
42 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack;
43 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack;
44 size_t MarkSweep::_preserved_count = 0;
45 size_t MarkSweep::_preserved_count_max = 0;
46 PreservedMark* MarkSweep::_preserved_marks = NULL;
47 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
48 STWGCTimer* MarkSweep::_gc_timer = NULL;
49 SerialOldTracer* MarkSweep::_gc_tracer = NULL;
50
51 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
52
53 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
54 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
55
56 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
57 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure);
58 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure);
59
60 void MarkSweep::MarkAndPushClosure::do_oop(oop* p) { mark_and_push(p); }
61 void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(p); }
62
63 void MarkSweep::follow_class_loader(ClassLoaderData* cld) {
64 MarkSweep::follow_cld_closure.do_cld(cld);
65 }
66
67 void MarkSweep::follow_array(objArrayOop array, int index) {
68 ObjArrayKlass* k = (ObjArrayKlass*)array->klass();
69 k->oop_follow_contents(array, index);
70 }
71
72 void MarkSweep::follow_stack() {
73 do {
74 while (!_marking_stack.is_empty()) {
75 oop obj = _marking_stack.pop();
76 assert (obj->is_gc_marked(), "p must be marked");
77 follow_object(obj);
78 }
79 // Process ObjArrays one at a time to avoid marking stack bloat.
80 if (!_objarray_stack.is_empty()) {
81 ObjArrayTask task = _objarray_stack.pop();
82 follow_array(objArrayOop(task.obj()), task.index());
83 }
84 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
85 }
86
87 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
88
89 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
90
91 void PreservedMark::adjust_pointer() {
92 MarkSweep::adjust_pointer(&_obj);
93 }
94
95 void PreservedMark::restore() {
96 _obj->set_mark(_mark);
97 }
98
99 // We preserve the mark which should be replaced at the end and the location
100 // that it will go. Note that the object that this markOop belongs to isn't
101 // currently at that address but it will be after phase4
102 void MarkSweep::preserve_mark(oop obj, markOop mark) {
103 // We try to store preserved marks in the to space of the new generation since
104 // this is storage which should be available. Most of the time this should be
105 // sufficient space for the marks we need to preserve but if it isn't we fall
106 // back to using Stacks to keep track of the overflow.
107 if (_preserved_count < _preserved_count_max) {
108 _preserved_marks[_preserved_count++].init(obj, mark);
109 } else {
110 _preserved_mark_stack.push(mark);
111 _preserved_oop_stack.push(obj);
112 }
113 }
114
115 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure;
116
117 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p); }
118 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p); }
119
120 void MarkSweep::adjust_marks() {
121 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
122 "inconsistent preserved oop stacks");
123
124 // adjust the oops we saved earlier
125 for (size_t i = 0; i < _preserved_count; i++) {
126 _preserved_marks[i].adjust_pointer();
127 }
128
129 // deal with the overflow stack
130 StackIterator<oop, mtGC> iter(_preserved_oop_stack);
131 while (!iter.is_empty()) {
132 oop* p = iter.next_addr();
133 adjust_pointer(p);
134 }
135 }
136
137 void MarkSweep::restore_marks() {
138 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
139 "inconsistent preserved oop stacks");
140 if (PrintGC && Verbose) {
141 gclog_or_tty->print_cr("Restoring " SIZE_FORMAT " marks",
142 _preserved_count + _preserved_oop_stack.size());
143 }
144
145 // restore the marks we saved earlier
146 for (size_t i = 0; i < _preserved_count; i++) {
147 _preserved_marks[i].restore();
148 }
149
150 // deal with the overflow
151 while (!_preserved_oop_stack.is_empty()) {
152 oop obj = _preserved_oop_stack.pop();
153 markOop mark = _preserved_mark_stack.pop();
154 obj->set_mark(mark);
155 }
156 }
157
158 MarkSweep::IsAliveClosure MarkSweep::is_alive;
159
160 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
161
162 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
163
164 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
165 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
166
167 void marksweep_init() {
168 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
169 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();
170 }
171
172 #ifndef PRODUCT
173
174 void MarkSweep::trace(const char* msg) {
175 if (TraceMarkSweep)
176 gclog_or_tty->print("%s", msg);
177 }
178
179 #endif