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/serial/markSweep.inline.hpp"
28 #include "gc/shared/collectedHeap.inline.hpp"
29 #include "gc/shared/gcTimer.hpp"
30 #include "gc/shared/gcTrace.hpp"
31 #include "gc/shared/specialized_oop_closures.hpp"
32 #include "memory/iterator.inline.hpp"
33 #include "oops/instanceClassLoaderKlass.inline.hpp"
34 #include "oops/instanceKlass.inline.hpp"
35 #include "oops/instanceMirrorKlass.inline.hpp"
36 #include "oops/instanceRefKlass.inline.hpp"
37 #include "oops/methodData.hpp"
38 #include "oops/objArrayKlass.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "oops/typeArrayOop.inline.hpp"
41 #include "utilities/macros.hpp"
42 #include "utilities/stack.inline.hpp"
43 #if INCLUDE_ALL_GCS
44 #include "gc/g1/g1StringDedup.hpp"
45 #endif // INCLUDE_ALL_GCS
46
47 uint MarkSweep::_total_invocations = 0;
48
49 Stack<oop, mtGC> MarkSweep::_marking_stack;
50 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack;
51
52 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack;
53 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack;
54 size_t MarkSweep::_preserved_count = 0;
55 size_t MarkSweep::_preserved_count_max = 0;
56 PreservedMark* MarkSweep::_preserved_marks = NULL;
57 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
58 STWGCTimer* MarkSweep::_gc_timer = NULL;
59 SerialOldTracer* MarkSweep::_gc_tracer = NULL;
60
61 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
62
63 MarkAndPushClosure MarkSweep::mark_and_push_closure;
64 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure);
65 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure);
66
67 inline void MarkSweep::mark_object(oop obj) {
68 #if INCLUDE_ALL_GCS
69 if (G1StringDedup::is_enabled()) {
70 // We must enqueue the object before it is marked
71 // as we otherwise can't read the object's age.
72 G1StringDedup::enqueue_from_mark(obj);
73 }
74 #endif
75 // some marks may contain information we need to preserve so we store them away
76 // and overwrite the mark. We'll restore it at the end of markSweep.
77 markOop mark = obj->mark();
78 obj->set_mark(markOopDesc::prototype()->set_marked());
79
80 if (mark->must_be_preserved(obj)) {
81 preserve_mark(obj, mark);
82 }
83 }
84
85 template <class T> inline void MarkSweep::mark_and_push(T* p) {
86 T heap_oop = oopDesc::load_heap_oop(p);
87 if (!oopDesc::is_null(heap_oop)) {
88 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
89 if (!obj->mark()->is_marked() &&
90 !is_archive_object(obj)) {
91 mark_object(obj);
92 _marking_stack.push(obj);
93 }
94 }
95 }
96
97 inline void MarkSweep::follow_klass(Klass* klass) {
98 oop op = klass->klass_holder();
99 MarkSweep::mark_and_push(&op);
100 }
101
102 inline void MarkSweep::follow_cld(ClassLoaderData* cld) {
103 MarkSweep::follow_cld_closure.do_cld(cld);
104 }
105
106 template <typename T>
107 inline void MarkAndPushClosure::do_oop_nv(T* p) { MarkSweep::mark_and_push(p); }
108 void MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); }
109 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
110 inline bool MarkAndPushClosure::do_metadata_nv() { return true; }
111 bool MarkAndPushClosure::do_metadata() { return do_metadata_nv(); }
112 inline void MarkAndPushClosure::do_klass_nv(Klass* k) { MarkSweep::follow_klass(k); }
113 void MarkAndPushClosure::do_klass(Klass* k) { do_klass_nv(k); }
114 inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); }
115 void MarkAndPushClosure::do_cld(ClassLoaderData* cld) { do_cld_nv(cld); }
116
117 template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {
118 mark_and_push(p);
119 }
120
121 void MarkSweep::push_objarray(oop obj, size_t index) {
122 ObjArrayTask task(obj, index);
123 assert(task.is_valid(), "bad ObjArrayTask");
124 _objarray_stack.push(task);
125 }
126
127 inline void MarkSweep::follow_array(objArrayOop array) {
128 MarkSweep::follow_klass(array->klass());
129 // Don't push empty arrays to avoid unnecessary work.
130 if (array->length() > 0) {
131 MarkSweep::push_objarray(array, 0);
132 }
133 }
134
135 inline void MarkSweep::follow_object(oop obj) {
136 assert(obj->is_gc_marked(), "should be marked");
137 if (obj->is_objArray()) {
138 // Handle object arrays explicitly to allow them to
139 // be split into chunks if needed.
140 MarkSweep::follow_array((objArrayOop)obj);
141 } else {
142 obj->oop_iterate(&mark_and_push_closure);
143 }
144 }
145
146 void MarkSweep::follow_array_chunk(objArrayOop array, int index) {
147 const int len = array->length();
148 const int beg_index = index;
149 assert(beg_index < len || len == 0, "index too large");
150
151 const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride);
152 const int end_index = beg_index + stride;
153
154 array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index);
155
156 if (end_index < len) {
157 MarkSweep::push_objarray(array, end_index); // Push the continuation.
158 }
159 }
160
161 void MarkSweep::follow_stack() {
162 do {
163 while (!_marking_stack.is_empty()) {
164 oop obj = _marking_stack.pop();
165 assert (obj->is_gc_marked(), "p must be marked");
166 follow_object(obj);
167 }
168 // Process ObjArrays one at a time to avoid marking stack bloat.
169 if (!_objarray_stack.is_empty()) {
170 ObjArrayTask task = _objarray_stack.pop();
171 follow_array_chunk(objArrayOop(task.obj()), task.index());
172 }
173 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
174 }
175
176 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
177
178 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }
179
180 template <class T> inline void MarkSweep::follow_root(T* p) {
181 assert(!Universe::heap()->is_in_reserved(p),
182 "roots shouldn't be things within the heap");
183 T heap_oop = oopDesc::load_heap_oop(p);
184 if (!oopDesc::is_null(heap_oop)) {
185 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
186 if (!obj->mark()->is_marked() &&
187 !is_archive_object(obj)) {
188 mark_object(obj);
189 follow_object(obj);
190 }
191 }
192 follow_stack();
193 }
194
195 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); }
196 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }
197
198 void PreservedMark::adjust_pointer() {
199 MarkSweep::adjust_pointer(&_obj);
200 }
201
202 void PreservedMark::restore() {
203 _obj->set_mark(_mark);
204 }
205
206 // We preserve the mark which should be replaced at the end and the location
207 // that it will go. Note that the object that this markOop belongs to isn't
208 // currently at that address but it will be after phase4
209 void MarkSweep::preserve_mark(oop obj, markOop mark) {
210 // We try to store preserved marks in the to space of the new generation since
211 // this is storage which should be available. Most of the time this should be
212 // sufficient space for the marks we need to preserve but if it isn't we fall
213 // back to using Stacks to keep track of the overflow.
214 if (_preserved_count < _preserved_count_max) {
215 _preserved_marks[_preserved_count++].init(obj, mark);
216 } else {
217 _preserved_mark_stack.push(mark);
218 _preserved_oop_stack.push(obj);
219 }
220 }
221
222 void MarkSweep::set_ref_processor(ReferenceProcessor* rp) {
223 _ref_processor = rp;
224 mark_and_push_closure.set_ref_processor(_ref_processor);
225 }
226
227 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure;
228
229 template <typename T>
230 void MarkSweep::AdjustPointerClosure::do_oop_nv(T* p) { adjust_pointer(p); }
231 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); }
232 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); }
233
234 void MarkSweep::adjust_marks() {
235 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
236 "inconsistent preserved oop stacks");
237
238 // adjust the oops we saved earlier
239 for (size_t i = 0; i < _preserved_count; i++) {
240 _preserved_marks[i].adjust_pointer();
241 }
242
243 // deal with the overflow stack
244 StackIterator<oop, mtGC> iter(_preserved_oop_stack);
245 while (!iter.is_empty()) {
246 oop* p = iter.next_addr();
247 adjust_pointer(p);
248 }
249 }
250
251 void MarkSweep::restore_marks() {
252 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
253 "inconsistent preserved oop stacks");
254 log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_oop_stack.size());
255
256 // restore the marks we saved earlier
257 for (size_t i = 0; i < _preserved_count; i++) {
258 _preserved_marks[i].restore();
259 }
260
261 // deal with the overflow
262 while (!_preserved_oop_stack.is_empty()) {
263 oop obj = _preserved_oop_stack.pop();
264 markOop mark = _preserved_mark_stack.pop();
265 obj->set_mark(mark);
266 }
267 }
268
269 MarkSweep::IsAliveClosure MarkSweep::is_alive;
270
271 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked() || is_archive_object(p); }
272
273 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
274
275 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
276 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }
277
278 void marksweep_init() {
279 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
280 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();
281 }
282
283 int InstanceKlass::oop_ms_adjust_pointers(oop obj) {
284 int size = size_helper();
285 oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::adjust_pointer_closure);
286 return size;
287 }
288
289 int InstanceMirrorKlass::oop_ms_adjust_pointers(oop obj) {
290 int size = oop_size(obj);
291 InstanceKlass::oop_ms_adjust_pointers(obj);
292
293 oop_oop_iterate_statics<true>(obj, &MarkSweep::adjust_pointer_closure);
294 return size;
295 }
296
297 int InstanceClassLoaderKlass::oop_ms_adjust_pointers(oop obj) {
298 return InstanceKlass::oop_ms_adjust_pointers(obj);
299 }
300
301 #ifdef ASSERT
302 template <class T> static void trace_reference_gc(const char *s, oop obj,
303 T* referent_addr,
304 T* next_addr,
305 T* discovered_addr) {
306 log_develop_trace(gc, ref)("%s obj " PTR_FORMAT, s, p2i(obj));
307 log_develop_trace(gc, ref)(" referent_addr/* " PTR_FORMAT " / " PTR_FORMAT,
308 p2i(referent_addr), p2i(referent_addr ? (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL));
309 log_develop_trace(gc, ref)(" next_addr/* " PTR_FORMAT " / " PTR_FORMAT,
310 p2i(next_addr), p2i(next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL));
311 log_develop_trace(gc, ref)(" discovered_addr/* " PTR_FORMAT " / " PTR_FORMAT,
312 p2i(discovered_addr), p2i(discovered_addr ? (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL));
313 }
314 #endif
315
316 template <class T> void static adjust_object_specialized(oop obj) {
317 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
318 MarkSweep::adjust_pointer(referent_addr);
319 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
320 MarkSweep::adjust_pointer(next_addr);
321 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
322 MarkSweep::adjust_pointer(discovered_addr);
323 debug_only(trace_reference_gc("InstanceRefKlass::oop_ms_adjust_pointers", obj,
324 referent_addr, next_addr, discovered_addr);)
325 }
326
327 int InstanceRefKlass::oop_ms_adjust_pointers(oop obj) {
328 int size = size_helper();
329 InstanceKlass::oop_ms_adjust_pointers(obj);
330
331 if (UseCompressedOops) {
332 adjust_object_specialized<narrowOop>(obj);
333 } else {
334 adjust_object_specialized<oop>(obj);
335 }
336 return size;
337 }
338
339 int ObjArrayKlass::oop_ms_adjust_pointers(oop obj) {
340 assert(obj->is_objArray(), "obj must be obj array");
341 objArrayOop a = objArrayOop(obj);
342 // Get size before changing pointers.
343 // Don't call size() or oop_size() since that is a virtual call.
344 int size = a->object_size();
345 oop_oop_iterate_elements<true>(a, &MarkSweep::adjust_pointer_closure);
346 return size;
347 }
348
349 int TypeArrayKlass::oop_ms_adjust_pointers(oop obj) {
350 assert(obj->is_typeArray(), "must be a type array");
351 typeArrayOop t = typeArrayOop(obj);
352 // Performance tweak: We skip iterating over the klass pointer since we
353 // know that Universe::TypeArrayKlass never moves.
354 return t->object_size();
355 }
356
357 // Generate MS specialized oop_oop_iterate functions.
358 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)