1 /*
2 * Copyright (c) 1997, 2010, 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/markSweep.inline.hpp"
28 #include "gc_interface/collectedHeap.inline.hpp"
29 #include "oops/methodDataOop.hpp"
30 #include "oops/objArrayKlass.inline.hpp"
31 #include "oops/oop.inline.hpp"
32
33 Stack<oop> MarkSweep::_marking_stack;
34 Stack<DataLayout*> MarkSweep::_revisit_mdo_stack;
35 Stack<Klass*> MarkSweep::_revisit_klass_stack;
36 Stack<ObjArrayTask> MarkSweep::_objarray_stack;
37
38 Stack<oop> MarkSweep::_preserved_oop_stack;
39 Stack<markOop> MarkSweep::_preserved_mark_stack;
40 size_t MarkSweep::_preserved_count = 0;
41 size_t MarkSweep::_preserved_count_max = 0;
42 PreservedMark* MarkSweep::_preserved_marks = NULL;
43 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
44
45 #ifdef VALIDATE_MARK_SWEEP
46 GrowableArray<void*>* MarkSweep::_root_refs_stack = NULL;
47 GrowableArray<oop> * MarkSweep::_live_oops = NULL;
48 GrowableArray<oop> * MarkSweep::_live_oops_moved_to = NULL;
49 GrowableArray<size_t>* MarkSweep::_live_oops_size = NULL;
50 size_t MarkSweep::_live_oops_index = 0;
51 size_t MarkSweep::_live_oops_index_at_perm = 0;
52 GrowableArray<void*>* MarkSweep::_other_refs_stack = NULL;
53 GrowableArray<void*>* MarkSweep::_adjusted_pointers = NULL;
54 bool MarkSweep::_pointer_tracking = false;
55 bool MarkSweep::_root_tracking = true;
56
57 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops = NULL;
58 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops_moved_to = NULL;
59 GrowableArray<size_t> * MarkSweep::_cur_gc_live_oops_size = NULL;
60 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops = NULL;
61 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops_moved_to = NULL;
62 GrowableArray<size_t> * MarkSweep::_last_gc_live_oops_size = NULL;
63 #endif
64
65 void MarkSweep::revisit_weak_klass_link(Klass* k) {
66 _revisit_klass_stack.push(k);
67 }
68
69 void MarkSweep::follow_weak_klass_links() {
70 // All klasses on the revisit stack are marked at this point.
71 // Update and follow all subklass, sibling and implementor links.
72 if (PrintRevisitStats) {
73 gclog_or_tty->print_cr("#classes in system dictionary = %d",
74 SystemDictionary::number_of_classes());
75 gclog_or_tty->print_cr("Revisit klass stack size = " SIZE_FORMAT,
76 _revisit_klass_stack.size());
77 }
78 while (!_revisit_klass_stack.is_empty()) {
79 Klass* const k = _revisit_klass_stack.pop();
80 k->follow_weak_klass_links(&is_alive, &keep_alive);
81 }
82 follow_stack();
83 }
84
85 void MarkSweep::revisit_mdo(DataLayout* p) {
86 _revisit_mdo_stack.push(p);
87 }
88
89 void MarkSweep::follow_mdo_weak_refs() {
90 // All strongly reachable oops have been marked at this point;
91 // we can visit and clear any weak references from MDO's which
92 // we memoized during the strong marking phase.
93 assert(_marking_stack.is_empty(), "Marking stack should be empty");
94 if (PrintRevisitStats) {
95 gclog_or_tty->print_cr("#classes in system dictionary = %d",
96 SystemDictionary::number_of_classes());
97 gclog_or_tty->print_cr("Revisit MDO stack size = " SIZE_FORMAT,
98 _revisit_mdo_stack.size());
99 }
100 while (!_revisit_mdo_stack.is_empty()) {
101 _revisit_mdo_stack.pop()->follow_weak_refs(&is_alive);
102 }
103 follow_stack();
104 }
105
106 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
107 CodeBlobToOopClosure MarkSweep::follow_code_root_closure(&MarkSweep::follow_root_closure, /*do_marking=*/ true);
108
109 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
110 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
111
112 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
113
114 void MarkSweep::MarkAndPushClosure::do_oop(oop* p) { mark_and_push(p); }
115 void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(p); }
116
117 void MarkSweep::follow_stack() {
118 do {
119 while (!_marking_stack.is_empty()) {
120 oop obj = _marking_stack.pop();
121 assert (obj->is_gc_marked(), "p must be marked");
122 obj->follow_contents();
123 }
124 // Process ObjArrays one at a time to avoid marking stack bloat.
125 if (!_objarray_stack.is_empty()) {
126 ObjArrayTask task = _objarray_stack.pop();
127 objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
128 k->oop_follow_contents(task.obj(), task.index());
129 }
130 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
131 }
132
133 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
134
135 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
136
137 // We preserve the mark which should be replaced at the end and the location
138 // that it will go. Note that the object that this markOop belongs to isn't
139 // currently at that address but it will be after phase4
140 void MarkSweep::preserve_mark(oop obj, markOop mark) {
141 // We try to store preserved marks in the to space of the new generation since
142 // this is storage which should be available. Most of the time this should be
143 // sufficient space for the marks we need to preserve but if it isn't we fall
144 // back to using Stacks to keep track of the overflow.
145 if (_preserved_count < _preserved_count_max) {
146 _preserved_marks[_preserved_count++].init(obj, mark);
147 } else {
148 _preserved_mark_stack.push(mark);
149 _preserved_oop_stack.push(obj);
150 }
151 }
152
153 MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);
154 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);
155
156 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p, _is_root); }
157 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }
158
159 void MarkSweep::adjust_marks() {
160 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
161 "inconsistent preserved oop stacks");
162
163 // adjust the oops we saved earlier
164 for (size_t i = 0; i < _preserved_count; i++) {
165 _preserved_marks[i].adjust_pointer();
166 }
167
168 // deal with the overflow stack
169 StackIterator<oop> iter(_preserved_oop_stack);
170 while (!iter.is_empty()) {
171 oop* p = iter.next_addr();
172 adjust_pointer(p);
173 }
174 }
175
176 void MarkSweep::restore_marks() {
177 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
178 "inconsistent preserved oop stacks");
179 if (PrintGC && Verbose) {
180 gclog_or_tty->print_cr("Restoring %d marks",
181 _preserved_count + _preserved_oop_stack.size());
182 }
183
184 // restore the marks we saved earlier
185 for (size_t i = 0; i < _preserved_count; i++) {
186 _preserved_marks[i].restore();
187 }
188
189 // deal with the overflow
190 while (!_preserved_oop_stack.is_empty()) {
191 oop obj = _preserved_oop_stack.pop();
192 markOop mark = _preserved_mark_stack.pop();
193 obj->set_mark(mark);
194 }
195 }
196
197 #ifdef VALIDATE_MARK_SWEEP
198
199 void MarkSweep::track_adjusted_pointer(void* p, bool isroot) {
200 if (!ValidateMarkSweep)
201 return;
202
203 if (!isroot) {
204 if (_pointer_tracking) {
205 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
206 _adjusted_pointers->remove(p);
207 }
208 } else {
209 ptrdiff_t index = _root_refs_stack->find(p);
210 if (index != -1) {
211 int l = _root_refs_stack->length();
212 if (l > 0 && l - 1 != index) {
213 void* last = _root_refs_stack->pop();
214 assert(last != p, "should be different");
215 _root_refs_stack->at_put(index, last);
216 } else {
217 _root_refs_stack->remove(p);
218 }
219 }
220 }
221 }
222
223 void MarkSweep::check_adjust_pointer(void* p) {
224 _adjusted_pointers->push(p);
225 }
226
227 class AdjusterTracker: public OopClosure {
228 public:
229 AdjusterTracker() {}
230 void do_oop(oop* o) { MarkSweep::check_adjust_pointer(o); }
231 void do_oop(narrowOop* o) { MarkSweep::check_adjust_pointer(o); }
232 };
233
234 void MarkSweep::track_interior_pointers(oop obj) {
235 if (ValidateMarkSweep) {
236 _adjusted_pointers->clear();
237 _pointer_tracking = true;
238
239 AdjusterTracker checker;
240 obj->oop_iterate(&checker);
241 }
242 }
243
244 void MarkSweep::check_interior_pointers() {
245 if (ValidateMarkSweep) {
246 _pointer_tracking = false;
247 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
248 }
249 }
250
251 void MarkSweep::reset_live_oop_tracking(bool at_perm) {
252 if (ValidateMarkSweep) {
253 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
254 _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
255 }
256 }
257
258 void MarkSweep::register_live_oop(oop p, size_t size) {
259 if (ValidateMarkSweep) {
260 _live_oops->push(p);
261 _live_oops_size->push(size);
262 _live_oops_index++;
263 }
264 }
265
266 void MarkSweep::validate_live_oop(oop p, size_t size) {
267 if (ValidateMarkSweep) {
268 oop obj = _live_oops->at((int)_live_oops_index);
269 guarantee(obj == p, "should be the same object");
270 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
271 _live_oops_index++;
272 }
273 }
274
275 void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,
276 HeapWord* compaction_top) {
277 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
278 "should be moved to forwarded location");
279 if (ValidateMarkSweep) {
280 MarkSweep::validate_live_oop(oop(q), size);
281 _live_oops_moved_to->push(oop(compaction_top));
282 }
283 if (RecordMarkSweepCompaction) {
284 _cur_gc_live_oops->push(q);
285 _cur_gc_live_oops_moved_to->push(compaction_top);
286 _cur_gc_live_oops_size->push(size);
287 }
288 }
289
290 void MarkSweep::compaction_complete() {
291 if (RecordMarkSweepCompaction) {
292 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
293 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
294 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
295
296 _cur_gc_live_oops = _last_gc_live_oops;
297 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
298 _cur_gc_live_oops_size = _last_gc_live_oops_size;
299 _last_gc_live_oops = _tmp_live_oops;
300 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
301 _last_gc_live_oops_size = _tmp_live_oops_size;
302 }
303 }
304
305 void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {
306 if (!RecordMarkSweepCompaction) {
307 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
308 return;
309 }
310
311 if (_last_gc_live_oops == NULL) {
312 tty->print_cr("No compaction information gathered yet");
313 return;
314 }
315
316 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
317 HeapWord* old_oop = _last_gc_live_oops->at(i);
318 size_t sz = _last_gc_live_oops_size->at(i);
319 if (old_oop <= q && q < (old_oop + sz)) {
320 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
321 size_t offset = (q - old_oop);
322 tty->print_cr("Address " PTR_FORMAT, q);
323 tty->print_cr(" Was in oop " PTR_FORMAT ", size " SIZE_FORMAT ", at offset " SIZE_FORMAT, old_oop, sz, offset);
324 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
325 return;
326 }
327 }
328
329 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
330 }
331 #endif //VALIDATE_MARK_SWEEP
332
333 MarkSweep::IsAliveClosure MarkSweep::is_alive;
334
335 void MarkSweep::IsAliveClosure::do_object(oop p) { ShouldNotReachHere(); }
336 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
337
338 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
339
340 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
341 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
342
343 void marksweep_init() { /* empty */ }
344
345 #ifndef PRODUCT
346
347 void MarkSweep::trace(const char* msg) {
348 if (TraceMarkSweep)
349 gclog_or_tty->print("%s", msg);
350 }
351
352 #endif