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 "utilities/macros.hpp" 41 #include "utilities/stack.inline.hpp" 42 #if INCLUDE_ALL_GCS 43 #include "gc/g1/g1StringDedup.hpp" 44 #endif // INCLUDE_ALL_GCS 45 46 uint MarkSweep::_total_invocations = 0; 47 48 Stack<oop, mtGC> MarkSweep::_marking_stack; 49 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack; 50 51 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack; 52 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack; 53 size_t MarkSweep::_preserved_count = 0; 54 size_t MarkSweep::_preserved_count_max = 0; 55 PreservedMark* MarkSweep::_preserved_marks = NULL; 56 ReferenceProcessor* MarkSweep::_ref_processor = NULL; 57 STWGCTimer* MarkSweep::_gc_timer = NULL; 58 SerialOldTracer* MarkSweep::_gc_tracer = NULL; 59 60 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure; 61 62 MarkAndPushClosure MarkSweep::mark_and_push_closure; 63 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure); 64 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure); 65 66 inline void MarkSweep::mark_object(oop obj) { 67 #if INCLUDE_ALL_GCS 68 if (G1StringDedup::is_enabled()) { 69 // We must enqueue the object before it is marked 70 // as we otherwise can't read the object's age. 71 G1StringDedup::enqueue_from_mark(obj); 72 } 73 #endif 74 // some marks may contain information we need to preserve so we store them away 75 // and overwrite the mark. We'll restore it at the end of markSweep. 76 markOop mark = obj->mark(); 77 obj->set_mark(markOopDesc::prototype()->set_marked()); 78 79 if (mark->must_be_preserved(obj)) { 80 preserve_mark(obj, mark); 81 } 82 } 83 84 template <class T> inline void MarkSweep::mark_and_push(T* p) { 85 T heap_oop = oopDesc::load_heap_oop(p); 86 if (!oopDesc::is_null(heap_oop)) { 87 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 88 if (!obj->mark()->is_marked() && 89 !is_archive_object(obj)) { 90 mark_object(obj); 91 _marking_stack.push(obj); 92 } 93 } 94 } 95 96 inline void MarkSweep::follow_klass(Klass* klass) { 97 oop op = klass->klass_holder(); 98 MarkSweep::mark_and_push(&op); 99 } 100 101 inline void MarkSweep::follow_cld(ClassLoaderData* cld) { 102 MarkSweep::follow_cld_closure.do_cld(cld); 103 } 104 105 template <typename T> 106 inline void MarkAndPushClosure::do_oop_nv(T* p) { MarkSweep::mark_and_push(p); } 107 void MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); } 108 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 109 inline bool MarkAndPushClosure::do_metadata_nv() { return true; } 110 bool MarkAndPushClosure::do_metadata() { return do_metadata_nv(); } 111 inline void MarkAndPushClosure::do_klass_nv(Klass* k) { MarkSweep::follow_klass(k); } 112 void MarkAndPushClosure::do_klass(Klass* k) { do_klass_nv(k); } 113 inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); } 114 void MarkAndPushClosure::do_cld(ClassLoaderData* cld) { do_cld_nv(cld); } 115 116 template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) { 117 mark_and_push(p); 118 } 119 120 void MarkSweep::push_objarray(oop obj, size_t index) { 121 ObjArrayTask task(obj, index); 122 assert(task.is_valid(), "bad ObjArrayTask"); 123 _objarray_stack.push(task); 124 } 125 126 inline void MarkSweep::follow_array(objArrayOop array) { 127 MarkSweep::follow_klass(array->klass()); 128 // Don't push empty arrays to avoid unnecessary work. 129 if (array->length() > 0) { 130 MarkSweep::push_objarray(array, 0); 131 } 132 } 133 134 inline void MarkSweep::follow_object(oop obj) { 135 assert(obj->is_gc_marked(), "should be marked"); 136 if (obj->is_objArray()) { 137 // Handle object arrays explicitly to allow them to 138 // be split into chunks if needed. 139 MarkSweep::follow_array((objArrayOop)obj); 140 } else { 141 obj->oop_iterate(&mark_and_push_closure); 142 } 143 } 144 145 void MarkSweep::follow_array_chunk(objArrayOop array, int index) { 146 const int len = array->length(); 147 const int beg_index = index; 148 assert(beg_index < len || len == 0, "index too large"); 149 150 const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride); 151 const int end_index = beg_index + stride; 152 153 array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index); 154 155 if (end_index < len) { 156 MarkSweep::push_objarray(array, end_index); // Push the continuation. 157 } 158 } 159 160 void MarkSweep::follow_stack() { 161 do { 162 while (!_marking_stack.is_empty()) { 163 oop obj = _marking_stack.pop(); 164 assert (obj->is_gc_marked(), "p must be marked"); 165 follow_object(obj); 166 } 167 // Process ObjArrays one at a time to avoid marking stack bloat. 168 if (!_objarray_stack.is_empty()) { 169 ObjArrayTask task = _objarray_stack.pop(); 170 follow_array_chunk(objArrayOop(task.obj()), task.index()); 171 } 172 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty()); 173 } 174 175 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure; 176 177 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); } 178 179 template <class T> inline void MarkSweep::follow_root(T* p) { 180 assert(!Universe::heap()->is_in_reserved(p), 181 "roots shouldn't be things within the heap"); 182 T heap_oop = oopDesc::load_heap_oop(p); 183 if (!oopDesc::is_null(heap_oop)) { 184 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 185 if (!obj->mark()->is_marked() && 186 !is_archive_object(obj)) { 187 mark_object(obj); 188 follow_object(obj); 189 } 190 } 191 follow_stack(); 192 } 193 194 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); } 195 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); } 196 197 void PreservedMark::adjust_pointer() { 198 MarkSweep::adjust_pointer(&_obj); 199 } 200 201 void PreservedMark::restore() { 202 _obj->set_mark(_mark); 203 } 204 205 // We preserve the mark which should be replaced at the end and the location 206 // that it will go. Note that the object that this markOop belongs to isn't 207 // currently at that address but it will be after phase4 208 void MarkSweep::preserve_mark(oop obj, markOop mark) { 209 // We try to store preserved marks in the to space of the new generation since 210 // this is storage which should be available. Most of the time this should be 211 // sufficient space for the marks we need to preserve but if it isn't we fall 212 // back to using Stacks to keep track of the overflow. 213 if (_preserved_count < _preserved_count_max) { 214 _preserved_marks[_preserved_count++].init(obj, mark); 215 } else { 216 _preserved_mark_stack.push(mark); 217 _preserved_oop_stack.push(obj); 218 } 219 } 220 221 void MarkSweep::set_ref_processor(ReferenceProcessor* rp) { 222 _ref_processor = rp; 223 mark_and_push_closure.set_ref_processor(_ref_processor); 224 } 225 226 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure; 227 228 template <typename T> 229 void MarkSweep::AdjustPointerClosure::do_oop_nv(T* p) { adjust_pointer(p); } 230 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); } 231 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 232 233 void MarkSweep::adjust_marks() { 234 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(), 235 "inconsistent preserved oop stacks"); 236 237 // adjust the oops we saved earlier 238 for (size_t i = 0; i < _preserved_count; i++) { 239 _preserved_marks[i].adjust_pointer(); 240 } 241 242 // deal with the overflow stack 243 StackIterator<oop, mtGC> iter(_preserved_oop_stack); 244 while (!iter.is_empty()) { 245 oop* p = iter.next_addr(); 246 adjust_pointer(p); 247 } 248 } 249 250 void MarkSweep::restore_marks() { 251 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(), 252 "inconsistent preserved oop stacks"); 253 if (PrintGC && Verbose) { 254 gclog_or_tty->print_cr("Restoring " SIZE_FORMAT " marks", 255 _preserved_count + _preserved_oop_stack.size()); 256 } 257 258 // restore the marks we saved earlier 259 for (size_t i = 0; i < _preserved_count; i++) { 260 _preserved_marks[i].restore(); 261 } 262 263 // deal with the overflow 264 while (!_preserved_oop_stack.is_empty()) { 265 oop obj = _preserved_oop_stack.pop(); 266 markOop mark = _preserved_mark_stack.pop(); 267 obj->set_mark(mark); 268 } 269 } 270 271 MarkSweep::IsAliveClosure MarkSweep::is_alive; 272 273 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked() || is_archive_object(p); } 274 275 MarkSweep::KeepAliveClosure MarkSweep::keep_alive; 276 277 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 278 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 279 280 void marksweep_init() { 281 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer(); 282 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer(); 283 } 284 285 int InstanceKlass::oop_ms_adjust_pointers(oop obj) { 286 int size = size_helper(); 287 oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::adjust_pointer_closure); 288 return size; 289 } 290 291 int InstanceMirrorKlass::oop_ms_adjust_pointers(oop obj) { 292 int size = oop_size(obj); 293 InstanceKlass::oop_ms_adjust_pointers(obj); 294 295 oop_oop_iterate_statics<true>(obj, &MarkSweep::adjust_pointer_closure); 296 return size; 297 } 298 299 int InstanceClassLoaderKlass::oop_ms_adjust_pointers(oop obj) { 300 return InstanceKlass::oop_ms_adjust_pointers(obj); 301 } 302 303 #ifdef ASSERT 304 template <class T> static void trace_reference_gc(const char *s, oop obj, 305 T* referent_addr, 306 T* next_addr, 307 T* discovered_addr) { 308 if(TraceReferenceGC && PrintGCDetails) { 309 gclog_or_tty->print_cr("%s obj " PTR_FORMAT, s, p2i(obj)); 310 gclog_or_tty->print_cr(" referent_addr/* " PTR_FORMAT " / " 311 PTR_FORMAT, p2i(referent_addr), 312 p2i(referent_addr ? 313 (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL)); 314 gclog_or_tty->print_cr(" next_addr/* " PTR_FORMAT " / " 315 PTR_FORMAT, p2i(next_addr), 316 p2i(next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL)); 317 gclog_or_tty->print_cr(" discovered_addr/* " PTR_FORMAT " / " 318 PTR_FORMAT, p2i(discovered_addr), 319 p2i(discovered_addr ? 320 (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL)); 321 } 322 } 323 #endif 324 325 template <class T> void static adjust_object_specialized(oop obj) { 326 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); 327 MarkSweep::adjust_pointer(referent_addr); 328 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); 329 MarkSweep::adjust_pointer(next_addr); 330 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); 331 MarkSweep::adjust_pointer(discovered_addr); 332 debug_only(trace_reference_gc("InstanceRefKlass::oop_ms_adjust_pointers", obj, 333 referent_addr, next_addr, discovered_addr);) 334 } 335 336 int InstanceRefKlass::oop_ms_adjust_pointers(oop obj) { 337 int size = size_helper(); 338 InstanceKlass::oop_ms_adjust_pointers(obj); 339 340 if (UseCompressedOops) { 341 adjust_object_specialized<narrowOop>(obj); 342 } else { 343 adjust_object_specialized<oop>(obj); 344 } 345 return size; 346 } 347 348 int ObjArrayKlass::oop_ms_adjust_pointers(oop obj) { 349 assert(obj->is_objArray(), "obj must be obj array"); 350 objArrayOop a = objArrayOop(obj); 351 // Get size before changing pointers. 352 // Don't call size() or oop_size() since that is a virtual call. 353 int size = a->object_size(); 354 oop_oop_iterate_elements<true>(a, &MarkSweep::adjust_pointer_closure); 355 return size; 356 } 357 358 int TypeArrayKlass::oop_ms_adjust_pointers(oop obj) { 359 assert(obj->is_typeArray(), "must be a type array"); 360 typeArrayOop t = typeArrayOop(obj); 361 // Performance tweak: We skip iterating over the klass pointer since we 362 // know that Universe::TypeArrayKlass never moves. 363 return t->object_size(); 364 } 365 366 // Generate MS specialized oop_oop_iterate functions. 367 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)