1 /*
2 * Copyright 1997-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_markSweep.cpp.incl"
27
28 GrowableArray<oop>* MarkSweep::_marking_stack = NULL;
29 GrowableArray<Klass*>* MarkSweep::_revisit_klass_stack = NULL;
30 GrowableArray<DataLayout*>* MarkSweep::_revisit_mdo_stack = NULL;
31
32 GrowableArray<oop>* MarkSweep::_preserved_oop_stack = NULL;
33 GrowableArray<markOop>* MarkSweep::_preserved_mark_stack= NULL;
34 size_t MarkSweep::_preserved_count = 0;
35 size_t MarkSweep::_preserved_count_max = 0;
36 PreservedMark* MarkSweep::_preserved_marks = NULL;
37 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
38
39 #ifdef VALIDATE_MARK_SWEEP
40 GrowableArray<void*>* MarkSweep::_root_refs_stack = NULL;
41 GrowableArray<oop> * MarkSweep::_live_oops = NULL;
42 GrowableArray<oop> * MarkSweep::_live_oops_moved_to = NULL;
43 GrowableArray<size_t>* MarkSweep::_live_oops_size = NULL;
44 size_t MarkSweep::_live_oops_index = 0;
45 size_t MarkSweep::_live_oops_index_at_perm = 0;
46 GrowableArray<void*>* MarkSweep::_other_refs_stack = NULL;
47 GrowableArray<void*>* MarkSweep::_adjusted_pointers = NULL;
48 bool MarkSweep::_pointer_tracking = false;
49 bool MarkSweep::_root_tracking = true;
50
51 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops = NULL;
52 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops_moved_to = NULL;
53 GrowableArray<size_t> * MarkSweep::_cur_gc_live_oops_size = NULL;
54 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops = NULL;
55 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops_moved_to = NULL;
56 GrowableArray<size_t> * MarkSweep::_last_gc_live_oops_size = NULL;
57 #endif
58
59 void MarkSweep::revisit_weak_klass_link(Klass* k) {
60 _revisit_klass_stack->push(k);
61 }
62
63 void MarkSweep::follow_weak_klass_links() {
64 // All klasses on the revisit stack are marked at this point.
65 // Update and follow all subklass, sibling and implementor links.
66 if (PrintRevisitStats) {
67 gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());
68 gclog_or_tty->print_cr("Revisit klass stack length = %d", _revisit_klass_stack->length());
69 }
70 for (int i = 0; i < _revisit_klass_stack->length(); i++) {
71 _revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
72 }
73 follow_stack();
74 }
75
76 #if ( defined(COMPILER1) || defined(COMPILER2) )
77 void MarkSweep::revisit_mdo(DataLayout* p) {
78 _revisit_mdo_stack->push(p);
79 }
80
81 void MarkSweep::follow_mdo_weak_refs() {
82 // All strongly reachable oops have been marked at this point;
83 // we can visit and clear any weak references from MDO's which
84 // we memoized during the strong marking phase.
85 assert(_marking_stack->is_empty(), "Marking stack should be empty");
86 if (PrintRevisitStats) {
87 gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());
88 gclog_or_tty->print_cr("Revisit MDO stack length = %d", _revisit_mdo_stack->length());
89 }
90 for (int i = 0; i < _revisit_mdo_stack->length(); i++) {
91 _revisit_mdo_stack->at(i)->follow_weak_refs(&is_alive);
92 }
93 follow_stack();
94 }
95 #endif // ( COMPILER1 || COMPILER2 )
96
97 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
98
99 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
100 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
101
102 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
103
104 void MarkSweep::MarkAndPushClosure::do_oop(oop* p) { mark_and_push(p); }
105 void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(p); }
106
107 void MarkSweep::follow_stack() {
108 while (!_marking_stack->is_empty()) {
109 oop obj = _marking_stack->pop();
110 assert (obj->is_gc_marked(), "p must be marked");
111 obj->follow_contents();
112 }
113 }
114
115 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
116
117 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
118
119 // We preserve the mark which should be replaced at the end and the location that it
120 // will go. Note that the object that this markOop belongs to isn't currently at that
121 // address but it will be after phase4
122 void MarkSweep::preserve_mark(oop obj, markOop mark) {
123 // we try to store preserved marks in the to space of the new generation since this
124 // is storage which should be available. Most of the time this should be sufficient
125 // space for the marks we need to preserve but if it isn't we fall back in using
126 // GrowableArrays to keep track of the overflow.
127 if (_preserved_count < _preserved_count_max) {
128 _preserved_marks[_preserved_count++].init(obj, mark);
129 } else {
130 if (_preserved_mark_stack == NULL) {
131 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);
132 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);
133 }
134 _preserved_mark_stack->push(mark);
135 _preserved_oop_stack->push(obj);
136 }
137 }
138
139 MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);
140 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);
141
142 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p, _is_root); }
143 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }
144
145 void MarkSweep::adjust_marks() {
146 assert(_preserved_oop_stack == NULL ||
147 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
148 "inconsistent preserved oop stacks");
149
150 // adjust the oops we saved earlier
151 for (size_t i = 0; i < _preserved_count; i++) {
152 _preserved_marks[i].adjust_pointer();
153 }
154
155 // deal with the overflow stack
156 if (_preserved_oop_stack) {
157 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
158 oop* p = _preserved_oop_stack->adr_at(i);
159 adjust_pointer(p);
160 }
161 }
162 }
163
164 void MarkSweep::restore_marks() {
165 assert(_preserved_oop_stack == NULL ||
166 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
167 "inconsistent preserved oop stacks");
168 if (PrintGC && Verbose) {
169 gclog_or_tty->print_cr("Restoring %d marks", _preserved_count +
170 (_preserved_oop_stack ? _preserved_oop_stack->length() : 0));
171 }
172
173 // restore the marks we saved earlier
174 for (size_t i = 0; i < _preserved_count; i++) {
175 _preserved_marks[i].restore();
176 }
177
178 // deal with the overflow
179 if (_preserved_oop_stack) {
180 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
181 oop obj = _preserved_oop_stack->at(i);
182 markOop mark = _preserved_mark_stack->at(i);
183 obj->set_mark(mark);
184 }
185 }
186 }
187
188 #ifdef VALIDATE_MARK_SWEEP
189
190 void MarkSweep::track_adjusted_pointer(void* p, bool isroot) {
191 if (!ValidateMarkSweep)
192 return;
193
194 if (!isroot) {
195 if (_pointer_tracking) {
196 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
197 _adjusted_pointers->remove(p);
198 }
199 } else {
200 ptrdiff_t index = _root_refs_stack->find(p);
201 if (index != -1) {
202 int l = _root_refs_stack->length();
203 if (l > 0 && l - 1 != index) {
204 void* last = _root_refs_stack->pop();
205 assert(last != p, "should be different");
206 _root_refs_stack->at_put(index, last);
207 } else {
208 _root_refs_stack->remove(p);
209 }
210 }
211 }
212 }
213
214 void MarkSweep::check_adjust_pointer(void* p) {
215 _adjusted_pointers->push(p);
216 }
217
218 class AdjusterTracker: public OopClosure {
219 public:
220 AdjusterTracker() {}
221 void do_oop(oop* o) { MarkSweep::check_adjust_pointer(o); }
222 void do_oop(narrowOop* o) { MarkSweep::check_adjust_pointer(o); }
223 };
224
225 void MarkSweep::track_interior_pointers(oop obj) {
226 if (ValidateMarkSweep) {
227 _adjusted_pointers->clear();
228 _pointer_tracking = true;
229
230 AdjusterTracker checker;
231 obj->oop_iterate(&checker);
232 }
233 }
234
235 void MarkSweep::check_interior_pointers() {
236 if (ValidateMarkSweep) {
237 _pointer_tracking = false;
238 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
239 }
240 }
241
242 void MarkSweep::reset_live_oop_tracking(bool at_perm) {
243 if (ValidateMarkSweep) {
244 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
245 _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
246 }
247 }
248
249 void MarkSweep::register_live_oop(oop p, size_t size) {
250 if (ValidateMarkSweep) {
251 _live_oops->push(p);
252 _live_oops_size->push(size);
253 _live_oops_index++;
254 }
255 }
256
257 void MarkSweep::validate_live_oop(oop p, size_t size) {
258 if (ValidateMarkSweep) {
259 oop obj = _live_oops->at((int)_live_oops_index);
260 guarantee(obj == p, "should be the same object");
261 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
262 _live_oops_index++;
263 }
264 }
265
266 void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,
267 HeapWord* compaction_top) {
268 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
269 "should be moved to forwarded location");
270 if (ValidateMarkSweep) {
271 MarkSweep::validate_live_oop(oop(q), size);
272 _live_oops_moved_to->push(oop(compaction_top));
273 }
274 if (RecordMarkSweepCompaction) {
275 _cur_gc_live_oops->push(q);
276 _cur_gc_live_oops_moved_to->push(compaction_top);
277 _cur_gc_live_oops_size->push(size);
278 }
279 }
280
281 void MarkSweep::compaction_complete() {
282 if (RecordMarkSweepCompaction) {
283 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
284 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
285 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
286
287 _cur_gc_live_oops = _last_gc_live_oops;
288 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
289 _cur_gc_live_oops_size = _last_gc_live_oops_size;
290 _last_gc_live_oops = _tmp_live_oops;
291 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
292 _last_gc_live_oops_size = _tmp_live_oops_size;
293 }
294 }
295
296 void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {
297 if (!RecordMarkSweepCompaction) {
298 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
299 return;
300 }
301
302 if (_last_gc_live_oops == NULL) {
303 tty->print_cr("No compaction information gathered yet");
304 return;
305 }
306
307 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
308 HeapWord* old_oop = _last_gc_live_oops->at(i);
309 size_t sz = _last_gc_live_oops_size->at(i);
310 if (old_oop <= q && q < (old_oop + sz)) {
311 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
312 size_t offset = (q - old_oop);
313 tty->print_cr("Address " PTR_FORMAT, q);
314 tty->print_cr(" Was in oop " PTR_FORMAT ", size " SIZE_FORMAT ", at offset " SIZE_FORMAT, old_oop, sz, offset);
315 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
316 return;
317 }
318 }
319
320 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
321 }
322 #endif //VALIDATE_MARK_SWEEP
323
324 MarkSweep::IsAliveClosure MarkSweep::is_alive;
325
326 void MarkSweep::IsAliveClosure::do_object(oop p) { ShouldNotReachHere(); }
327 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
328
329 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
330
331 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
332 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
333
334 void marksweep_init() { /* empty */ }
335
336 #ifndef PRODUCT
337
338 void MarkSweep::trace(const char* msg) {
339 if (TraceMarkSweep)
340 gclog_or_tty->print("%s", msg);
341 }
342
343 #endif