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 GrowableArray<oop>* MarkSweep::_marking_stack = NULL;
34 GrowableArray<ObjArrayTask>* MarkSweep::_objarray_stack = NULL;
35 GrowableArray<Klass*>* MarkSweep::_revisit_klass_stack = NULL;
36 GrowableArray<DataLayout*>* MarkSweep::_revisit_mdo_stack = NULL;
37
38 GrowableArray<oop>* MarkSweep::_preserved_oop_stack = NULL;
39 GrowableArray<markOop>* MarkSweep::_preserved_mark_stack= NULL;
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", SystemDictionary::number_of_classes());
74 gclog_or_tty->print_cr("Revisit klass stack length = %d", _revisit_klass_stack->length());
75 }
76 for (int i = 0; i < _revisit_klass_stack->length(); i++) {
77 _revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
78 }
79 follow_stack();
80 }
81
82 void MarkSweep::revisit_mdo(DataLayout* p) {
83 _revisit_mdo_stack->push(p);
84 }
85
86 void MarkSweep::follow_mdo_weak_refs() {
87 // All strongly reachable oops have been marked at this point;
88 // we can visit and clear any weak references from MDO's which
89 // we memoized during the strong marking phase.
90 assert(_marking_stack->is_empty(), "Marking stack should be empty");
91 if (PrintRevisitStats) {
92 gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());
93 gclog_or_tty->print_cr("Revisit MDO stack length = %d", _revisit_mdo_stack->length());
94 }
95 for (int i = 0; i < _revisit_mdo_stack->length(); i++) {
96 _revisit_mdo_stack->at(i)->follow_weak_refs(&is_alive);
97 }
98 follow_stack();
99 }
100
101 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
102 CodeBlobToOopClosure MarkSweep::follow_code_root_closure(&MarkSweep::follow_root_closure, /*do_marking=*/ true);
103
104 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
105 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
106
107 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
108
109 void MarkSweep::MarkAndPushClosure::do_oop(oop* p) { mark_and_push(p); }
110 void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(p); }
111
112 void MarkSweep::follow_stack() {
113 do {
114 while (!_marking_stack->is_empty()) {
115 oop obj = _marking_stack->pop();
116 assert (obj->is_gc_marked(), "p must be marked");
117 obj->follow_contents();
118 }
119 // Process ObjArrays one at a time to avoid marking stack bloat.
120 if (!_objarray_stack->is_empty()) {
121 ObjArrayTask task = _objarray_stack->pop();
122 objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
123 k->oop_follow_contents(task.obj(), task.index());
124 }
125 } while (!_marking_stack->is_empty() || !_objarray_stack->is_empty());
126 }
127
128 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
129
130 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
131
132 // We preserve the mark which should be replaced at the end and the location that it
133 // will go. Note that the object that this markOop belongs to isn't currently at that
134 // address but it will be after phase4
135 void MarkSweep::preserve_mark(oop obj, markOop mark) {
136 // we try to store preserved marks in the to space of the new generation since this
137 // is storage which should be available. Most of the time this should be sufficient
138 // space for the marks we need to preserve but if it isn't we fall back in using
139 // GrowableArrays to keep track of the overflow.
140 if (_preserved_count < _preserved_count_max) {
141 _preserved_marks[_preserved_count++].init(obj, mark);
142 } else {
143 if (_preserved_mark_stack == NULL) {
144 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);
145 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);
146 }
147 _preserved_mark_stack->push(mark);
148 _preserved_oop_stack->push(obj);
149 }
150 }
151
152 MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);
153 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);
154
155 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p, _is_root); }
156 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }
157
158 void MarkSweep::adjust_marks() {
159 assert(_preserved_oop_stack == NULL ||
160 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
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 if (_preserved_oop_stack) {
170 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
171 oop* p = _preserved_oop_stack->adr_at(i);
172 adjust_pointer(p);
173 }
174 }
175 }
176
177 void MarkSweep::restore_marks() {
178 assert(_preserved_oop_stack == NULL ||
179 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
180 "inconsistent preserved oop stacks");
181 if (PrintGC && Verbose) {
182 gclog_or_tty->print_cr("Restoring %d marks", _preserved_count +
183 (_preserved_oop_stack ? _preserved_oop_stack->length() : 0));
184 }
185
186 // restore the marks we saved earlier
187 for (size_t i = 0; i < _preserved_count; i++) {
188 _preserved_marks[i].restore();
189 }
190
191 // deal with the overflow
192 if (_preserved_oop_stack) {
193 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
194 oop obj = _preserved_oop_stack->at(i);
195 markOop mark = _preserved_mark_stack->at(i);
196 obj->set_mark(mark);
197 }
198 }
199 }
200
201 #ifdef VALIDATE_MARK_SWEEP
202
203 void MarkSweep::track_adjusted_pointer(void* p, bool isroot) {
204 if (!ValidateMarkSweep)
205 return;
206
207 if (!isroot) {
208 if (_pointer_tracking) {
209 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
210 _adjusted_pointers->remove(p);
211 }
212 } else {
213 ptrdiff_t index = _root_refs_stack->find(p);
214 if (index != -1) {
215 int l = _root_refs_stack->length();
216 if (l > 0 && l - 1 != index) {
217 void* last = _root_refs_stack->pop();
218 assert(last != p, "should be different");
219 _root_refs_stack->at_put(index, last);
220 } else {
221 _root_refs_stack->remove(p);
222 }
223 }
224 }
225 }
226
227 void MarkSweep::check_adjust_pointer(void* p) {
228 _adjusted_pointers->push(p);
229 }
230
231 class AdjusterTracker: public OopClosure {
232 public:
233 AdjusterTracker() {}
234 void do_oop(oop* o) { MarkSweep::check_adjust_pointer(o); }
235 void do_oop(narrowOop* o) { MarkSweep::check_adjust_pointer(o); }
236 };
237
238 void MarkSweep::track_interior_pointers(oop obj) {
239 if (ValidateMarkSweep) {
240 _adjusted_pointers->clear();
241 _pointer_tracking = true;
242
243 AdjusterTracker checker;
244 obj->oop_iterate(&checker);
245 }
246 }
247
248 void MarkSweep::check_interior_pointers() {
249 if (ValidateMarkSweep) {
250 _pointer_tracking = false;
251 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
252 }
253 }
254
255 void MarkSweep::reset_live_oop_tracking(bool at_perm) {
256 if (ValidateMarkSweep) {
257 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
258 _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
259 }
260 }
261
262 void MarkSweep::register_live_oop(oop p, size_t size) {
263 if (ValidateMarkSweep) {
264 _live_oops->push(p);
265 _live_oops_size->push(size);
266 _live_oops_index++;
267 }
268 }
269
270 void MarkSweep::validate_live_oop(oop p, size_t size) {
271 if (ValidateMarkSweep) {
272 oop obj = _live_oops->at((int)_live_oops_index);
273 guarantee(obj == p, "should be the same object");
274 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
275 _live_oops_index++;
276 }
277 }
278
279 void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,
280 HeapWord* compaction_top) {
281 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
282 "should be moved to forwarded location");
283 if (ValidateMarkSweep) {
284 MarkSweep::validate_live_oop(oop(q), size);
285 _live_oops_moved_to->push(oop(compaction_top));
286 }
287 if (RecordMarkSweepCompaction) {
288 _cur_gc_live_oops->push(q);
289 _cur_gc_live_oops_moved_to->push(compaction_top);
290 _cur_gc_live_oops_size->push(size);
291 }
292 }
293
294 void MarkSweep::compaction_complete() {
295 if (RecordMarkSweepCompaction) {
296 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
297 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
298 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
299
300 _cur_gc_live_oops = _last_gc_live_oops;
301 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
302 _cur_gc_live_oops_size = _last_gc_live_oops_size;
303 _last_gc_live_oops = _tmp_live_oops;
304 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
305 _last_gc_live_oops_size = _tmp_live_oops_size;
306 }
307 }
308
309 void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {
310 if (!RecordMarkSweepCompaction) {
311 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
312 return;
313 }
314
315 if (_last_gc_live_oops == NULL) {
316 tty->print_cr("No compaction information gathered yet");
317 return;
318 }
319
320 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
321 HeapWord* old_oop = _last_gc_live_oops->at(i);
322 size_t sz = _last_gc_live_oops_size->at(i);
323 if (old_oop <= q && q < (old_oop + sz)) {
324 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
325 size_t offset = (q - old_oop);
326 tty->print_cr("Address " PTR_FORMAT, q);
327 tty->print_cr(" Was in oop " PTR_FORMAT ", size " SIZE_FORMAT ", at offset " SIZE_FORMAT, old_oop, sz, offset);
328 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
329 return;
330 }
331 }
332
333 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
334 }
335 #endif //VALIDATE_MARK_SWEEP
336
337 MarkSweep::IsAliveClosure MarkSweep::is_alive;
338
339 void MarkSweep::IsAliveClosure::do_object(oop p) { ShouldNotReachHere(); }
340 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }
341
342 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
343
344 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
345 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
346
347 void marksweep_init() { /* empty */ }
348
349 #ifndef PRODUCT
350
351 void MarkSweep::trace(const char* msg) {
352 if (TraceMarkSweep)
353 gclog_or_tty->print("%s", msg);
354 }
355
356 #endif