43
44 Stack<oop, mtGC> MarkSweep::_marking_stack;
45 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
46
47 Stack<PreservedMark, mtGC> MarkSweep::_preserved_overflow_stack;
48 size_t MarkSweep::_preserved_count = 0;
49 size_t MarkSweep::_preserved_count_max = 0;
50 PreservedMark* MarkSweep::_preserved_marks = nullptr;
51 STWGCTimer* MarkSweep::_gc_timer = nullptr;
52 SerialOldTracer* MarkSweep::_gc_tracer = nullptr;
53
54 AlwaysTrueClosure MarkSweep::_always_true_closure;
55 ReferenceProcessor* MarkSweep::_ref_processor;
56
57 StringDedup::Requests* MarkSweep::_string_dedup_requests = nullptr;
58
59 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
60
61 MarkAndPushClosure MarkSweep::mark_and_push_closure(ClassLoaderData::_claim_stw_fullgc_mark);
62 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure, ClassLoaderData::_claim_stw_fullgc_mark);
63 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure, ClassLoaderData::_claim_stw_fullgc_adjust);
64
65 template <class T> void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
66 mark_and_push(p);
67 }
68
69 void MarkSweep::push_objarray(oop obj, size_t index) {
70 ObjArrayTask task(obj, index);
71 assert(task.is_valid(), "bad ObjArrayTask");
72 _objarray_stack.push(task);
73 }
74
75 void MarkSweep::follow_array(objArrayOop array) {
76 mark_and_push_closure.do_klass(array->klass());
77 // Don't push empty arrays to avoid unnecessary work.
78 if (array->length() > 0) {
79 MarkSweep::push_objarray(array, 0);
80 }
81 }
82
83 void MarkSweep::follow_object(oop obj) {
125
126 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
127
128 template <class T> void MarkSweep::follow_root(T* p) {
129 assert(!Universe::heap()->is_in(p),
130 "roots shouldn't be things within the heap");
131 T heap_oop = RawAccess<>::oop_load(p);
132 if (!CompressedOops::is_null(heap_oop)) {
133 oop obj = CompressedOops::decode_not_null(heap_oop);
134 if (!obj->mark().is_marked()) {
135 mark_object(obj);
136 follow_object(obj);
137 }
138 }
139 follow_stack();
140 }
141
142 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
143 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
144
145 void PreservedMark::adjust_pointer() {
146 MarkSweep::adjust_pointer(&_obj);
147 }
148
149 void PreservedMark::restore() {
150 _obj->set_mark(_mark);
151 }
152
153 // We preserve the mark which should be replaced at the end and the location
154 // that it will go. Note that the object that this markWord belongs to isn't
155 // currently at that address but it will be after phase4
156 void MarkSweep::preserve_mark(oop obj, markWord mark) {
157 // We try to store preserved marks in the to space of the new generation since
158 // this is storage which should be available. Most of the time this should be
159 // sufficient space for the marks we need to preserve but if it isn't we fall
160 // back to using Stacks to keep track of the overflow.
161 if (_preserved_count < _preserved_count_max) {
162 _preserved_marks[_preserved_count++] = PreservedMark(obj, mark);
163 } else {
164 _preserved_overflow_stack.push(PreservedMark(obj, mark));
165 }
166 }
167
168 void MarkSweep::mark_object(oop obj) {
169 if (StringDedup::is_enabled() &&
170 java_lang_String::is_instance(obj) &&
171 SerialStringDedup::is_candidate_from_mark(obj)) {
172 _string_dedup_requests->add(obj);
173 }
174
175 // some marks may contain information we need to preserve so we store them away
176 // and overwrite the mark. We'll restore it at the end of markSweep.
177 markWord mark = obj->mark();
178 obj->set_mark(markWord::prototype().set_marked());
179
180 ContinuationGCSupport::transform_stack_chunk(obj);
181
182 if (obj->mark_must_be_preserved(mark)) {
183 preserve_mark(obj, mark);
184 }
185 }
186
187 template <class T> void MarkSweep::mark_and_push(T* p) {
188 T heap_oop = RawAccess<>::oop_load(p);
189 if (!CompressedOops::is_null(heap_oop)) {
190 oop obj = CompressedOops::decode_not_null(heap_oop);
191 if (!obj->mark().is_marked()) {
192 mark_object(obj);
193 _marking_stack.push(obj);
194 }
195 }
196 }
197
198 template <typename T>
199 void MarkAndPushClosure::do_oop_work(T* p) { MarkSweep::mark_and_push(p); }
200 void MarkAndPushClosure::do_oop( oop* p) { do_oop_work(p); }
201 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_work(p); }
202
203 AdjustPointerClosure MarkSweep::adjust_pointer_closure;
204
205 void MarkSweep::adjust_marks() {
206 // adjust the oops we saved earlier
207 for (size_t i = 0; i < _preserved_count; i++) {
208 _preserved_marks[i].adjust_pointer();
209 }
210
211 // deal with the overflow stack
212 StackIterator<PreservedMark, mtGC> iter(_preserved_overflow_stack);
213 while (!iter.is_empty()) {
214 PreservedMark* p = iter.next_addr();
215 p->adjust_pointer();
216 }
217 }
218
219 void MarkSweep::restore_marks() {
220 log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_overflow_stack.size());
221
222 // restore the marks we saved earlier
223 for (size_t i = 0; i < _preserved_count; i++) {
224 _preserved_marks[i].restore();
225 }
226
227 // deal with the overflow
228 while (!_preserved_overflow_stack.is_empty()) {
229 PreservedMark p = _preserved_overflow_stack.pop();
230 p.restore();
231 }
232 }
233
234 MarkSweep::IsAliveClosure MarkSweep::is_alive;
235
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43
44 Stack<oop, mtGC> MarkSweep::_marking_stack;
45 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
46
47 Stack<PreservedMark, mtGC> MarkSweep::_preserved_overflow_stack;
48 size_t MarkSweep::_preserved_count = 0;
49 size_t MarkSweep::_preserved_count_max = 0;
50 PreservedMark* MarkSweep::_preserved_marks = nullptr;
51 STWGCTimer* MarkSweep::_gc_timer = nullptr;
52 SerialOldTracer* MarkSweep::_gc_tracer = nullptr;
53
54 AlwaysTrueClosure MarkSweep::_always_true_closure;
55 ReferenceProcessor* MarkSweep::_ref_processor;
56
57 StringDedup::Requests* MarkSweep::_string_dedup_requests = nullptr;
58
59 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
60
61 MarkAndPushClosure MarkSweep::mark_and_push_closure(ClassLoaderData::_claim_stw_fullgc_mark);
62 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure, ClassLoaderData::_claim_stw_fullgc_mark);
63
64 template <class T> void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
65 mark_and_push(p);
66 }
67
68 void MarkSweep::push_objarray(oop obj, size_t index) {
69 ObjArrayTask task(obj, index);
70 assert(task.is_valid(), "bad ObjArrayTask");
71 _objarray_stack.push(task);
72 }
73
74 void MarkSweep::follow_array(objArrayOop array) {
75 mark_and_push_closure.do_klass(array->klass());
76 // Don't push empty arrays to avoid unnecessary work.
77 if (array->length() > 0) {
78 MarkSweep::push_objarray(array, 0);
79 }
80 }
81
82 void MarkSweep::follow_object(oop obj) {
124
125 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
126
127 template <class T> void MarkSweep::follow_root(T* p) {
128 assert(!Universe::heap()->is_in(p),
129 "roots shouldn't be things within the heap");
130 T heap_oop = RawAccess<>::oop_load(p);
131 if (!CompressedOops::is_null(heap_oop)) {
132 oop obj = CompressedOops::decode_not_null(heap_oop);
133 if (!obj->mark().is_marked()) {
134 mark_object(obj);
135 follow_object(obj);
136 }
137 }
138 follow_stack();
139 }
140
141 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
142 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
143
144 template <bool ALT_FWD>
145 void PreservedMark::adjust_pointer() {
146 MarkSweep::adjust_pointer<ALT_FWD>(&_obj);
147 }
148
149 void PreservedMark::restore() {
150 _obj->set_mark(_mark);
151 }
152
153 // We preserve the mark which should be replaced at the end and the location
154 // that it will go. Note that the object that this markWord belongs to isn't
155 // currently at that address but it will be after phase4
156 void MarkSweep::preserve_mark(oop obj, markWord mark) {
157 // We try to store preserved marks in the to space of the new generation since
158 // this is storage which should be available. Most of the time this should be
159 // sufficient space for the marks we need to preserve but if it isn't we fall
160 // back to using Stacks to keep track of the overflow.
161 if (_preserved_count < _preserved_count_max) {
162 _preserved_marks[_preserved_count++] = PreservedMark(obj, mark);
163 } else {
164 _preserved_overflow_stack.push(PreservedMark(obj, mark));
165 }
166 }
167
168 void MarkSweep::mark_object(oop obj) {
169 if (StringDedup::is_enabled() &&
170 java_lang_String::is_instance(obj) &&
171 SerialStringDedup::is_candidate_from_mark(obj)) {
172 _string_dedup_requests->add(obj);
173 }
174
175 // Do the transform while we still have the header intact,
176 // which might include important class information.
177 ContinuationGCSupport::transform_stack_chunk(obj);
178
179 // some marks may contain information we need to preserve so we store them away
180 // and overwrite the mark. We'll restore it at the end of markSweep.
181 markWord mark = obj->mark();
182 obj->set_mark(obj->prototype_mark().set_marked());
183
184 if (obj->mark_must_be_preserved(mark)) {
185 preserve_mark(obj, mark);
186 }
187 }
188
189 template <class T> void MarkSweep::mark_and_push(T* p) {
190 T heap_oop = RawAccess<>::oop_load(p);
191 if (!CompressedOops::is_null(heap_oop)) {
192 oop obj = CompressedOops::decode_not_null(heap_oop);
193 if (!obj->mark().is_marked()) {
194 mark_object(obj);
195 _marking_stack.push(obj);
196 }
197 }
198 }
199
200 template <typename T>
201 void MarkAndPushClosure::do_oop_work(T* p) { MarkSweep::mark_and_push(p); }
202 void MarkAndPushClosure::do_oop( oop* p) { do_oop_work(p); }
203 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_work(p); }
204
205 template <bool ALT_FWD>
206 void MarkSweep::adjust_marks_impl() {
207 // adjust the oops we saved earlier
208 for (size_t i = 0; i < _preserved_count; i++) {
209 _preserved_marks[i].adjust_pointer<ALT_FWD>();
210 }
211
212 // deal with the overflow stack
213 StackIterator<PreservedMark, mtGC> iter(_preserved_overflow_stack);
214 while (!iter.is_empty()) {
215 PreservedMark* p = iter.next_addr();
216 p->adjust_pointer<ALT_FWD>();
217 }
218 }
219
220 void MarkSweep::adjust_marks() {
221 if (UseAltGCForwarding) {
222 adjust_marks_impl<true>();
223 } else {
224 adjust_marks_impl<false>();
225 }
226 }
227
228 void MarkSweep::restore_marks() {
229 log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_overflow_stack.size());
230
231 // restore the marks we saved earlier
232 for (size_t i = 0; i < _preserved_count; i++) {
233 _preserved_marks[i].restore();
234 }
235
236 // deal with the overflow
237 while (!_preserved_overflow_stack.is_empty()) {
238 PreservedMark p = _preserved_overflow_stack.pop();
239 p.restore();
240 }
241 }
242
243 MarkSweep::IsAliveClosure MarkSweep::is_alive;
244
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