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_implementation/shared/gcTimer.hpp" 28 #include "gc_implementation/shared/gcTrace.hpp" 29 #include "gc_implementation/shared/markSweep.inline.hpp" 30 #include "gc_interface/collectedHeap.inline.hpp" 31 #include "oops/instanceKlass.inline.hpp" 32 #include "oops/instanceMirrorKlass.inline.hpp" 33 #include "oops/methodData.hpp" 34 #include "oops/objArrayKlass.inline.hpp" 35 #include "oops/oop.inline.hpp" 36 37 uint MarkSweep::_total_invocations = 0; 38 39 Stack<oop, mtGC> MarkSweep::_marking_stack; 40 Stack<ObjArrayTask, mtGC> MarkSweep::_objarray_stack; 41 42 Stack<oop, mtGC> MarkSweep::_preserved_oop_stack; 43 Stack<markOop, mtGC> MarkSweep::_preserved_mark_stack; 44 size_t MarkSweep::_preserved_count = 0; 45 size_t MarkSweep::_preserved_count_max = 0; 46 PreservedMark* MarkSweep::_preserved_marks = NULL; 47 ReferenceProcessor* MarkSweep::_ref_processor = NULL; 48 STWGCTimer* MarkSweep::_gc_timer = NULL; 49 SerialOldTracer* MarkSweep::_gc_tracer = NULL; 50 51 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure; 52 53 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); } 54 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); } 55 56 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure; 57 CLDToOopClosure MarkSweep::follow_cld_closure(&mark_and_push_closure); 58 CLDToOopClosure MarkSweep::adjust_cld_closure(&adjust_pointer_closure); 59 60 template <typename T> 61 void MarkSweep::MarkAndPushClosure::do_oop_nv(T* p) { mark_and_push(p); } 62 void MarkSweep::MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); } 63 void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 64 65 void MarkSweep::follow_class_loader(ClassLoaderData* cld) { 66 MarkSweep::follow_cld_closure.do_cld(cld); 67 } 68 69 void InstanceKlass::oop_ms_follow_contents(oop obj) { 70 assert(obj != NULL, "can't follow the content of NULL object"); 71 MarkSweep::follow_klass(this); 72 73 oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::mark_and_push_closure); 74 } 75 76 void InstanceMirrorKlass::oop_ms_follow_contents(oop obj) { 77 InstanceKlass::oop_ms_follow_contents(obj); 78 79 // Follow the klass field in the mirror 80 Klass* klass = java_lang_Class::as_Klass(obj); 81 if (klass != NULL) { 82 // An anonymous class doesn't have its own class loader, so the call 83 // to follow_klass will mark and push its java mirror instead of the 84 // class loader. When handling the java mirror for an anonymous class 85 // we need to make sure its class loader data is claimed, this is done 86 // by calling follow_class_loader explicitly. For non-anonymous classes 87 // the call to follow_class_loader is made when the class loader itself 88 // is handled. 89 if (klass->oop_is_instance() && InstanceKlass::cast(klass)->is_anonymous()) { 90 MarkSweep::follow_class_loader(klass->class_loader_data()); 91 } else { 92 MarkSweep::follow_klass(klass); 93 } 94 } else { 95 // If klass is NULL then this a mirror for a primitive type. 96 // We don't have to follow them, since they are handled as strong 97 // roots in Universe::oops_do. 98 assert(java_lang_Class::is_primitive(obj), "Sanity check"); 99 } 100 101 oop_oop_iterate_statics<true>(obj, &MarkSweep::mark_and_push_closure); 102 } 103 104 void InstanceClassLoaderKlass::oop_ms_follow_contents(oop obj) { 105 InstanceKlass::oop_ms_follow_contents(obj); 106 107 ClassLoaderData * const loader_data = java_lang_ClassLoader::loader_data(obj); 108 109 // We must NULL check here, since the class loader 110 // can be found before the loader data has been set up. 111 if(loader_data != NULL) { 112 MarkSweep::follow_class_loader(loader_data); 113 } 114 } 115 116 template <class T> 117 static void oop_ms_follow_contents_specialized(InstanceRefKlass* klass, oop obj) { 118 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); 119 T heap_oop = oopDesc::load_heap_oop(referent_addr); 120 debug_only( 121 if(TraceReferenceGC && PrintGCDetails) { 122 gclog_or_tty->print_cr("InstanceRefKlass::oop_ms_follow_contents_specialized " PTR_FORMAT, p2i(obj)); 123 } 124 ) 125 if (!oopDesc::is_null(heap_oop)) { 126 oop referent = oopDesc::decode_heap_oop_not_null(heap_oop); 127 if (!referent->is_gc_marked() && 128 MarkSweep::ref_processor()->discover_reference(obj, klass->reference_type())) { 129 // reference was discovered, referent will be traversed later 130 klass->InstanceKlass::oop_ms_follow_contents(obj); 131 debug_only( 132 if(TraceReferenceGC && PrintGCDetails) { 133 gclog_or_tty->print_cr(" Non NULL enqueued " PTR_FORMAT, p2i(obj)); 134 } 135 ) 136 return; 137 } else { 138 // treat referent as normal oop 139 debug_only( 140 if(TraceReferenceGC && PrintGCDetails) { 141 gclog_or_tty->print_cr(" Non NULL normal " PTR_FORMAT, p2i(obj)); 142 } 143 ) 144 MarkSweep::mark_and_push(referent_addr); 145 } 146 } 147 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); 148 // Treat discovered as normal oop, if ref is not "active", 149 // i.e. if next is non-NULL. 150 T next_oop = oopDesc::load_heap_oop(next_addr); 151 if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active" 152 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); 153 debug_only( 154 if(TraceReferenceGC && PrintGCDetails) { 155 gclog_or_tty->print_cr(" Process discovered as normal " 156 PTR_FORMAT, p2i(discovered_addr)); 157 } 158 ) 159 MarkSweep::mark_and_push(discovered_addr); 160 } 161 // treat next as normal oop. next is a link in the reference queue. 162 debug_only( 163 if(TraceReferenceGC && PrintGCDetails) { 164 gclog_or_tty->print_cr(" Process next as normal " PTR_FORMAT, p2i(next_addr)); 165 } 166 ) 167 MarkSweep::mark_and_push(next_addr); 168 klass->InstanceKlass::oop_ms_follow_contents(obj); 169 } 170 171 void InstanceRefKlass::oop_ms_follow_contents(oop obj) { 172 if (UseCompressedOops) { 173 oop_ms_follow_contents_specialized<narrowOop>(this, obj); 174 } else { 175 oop_ms_follow_contents_specialized<oop>(this, obj); 176 } 177 } 178 179 template <class T> 180 static void oop_ms_follow_contents_specialized(oop obj, int index) { 181 objArrayOop a = objArrayOop(obj); 182 const size_t len = size_t(a->length()); 183 const size_t beg_index = size_t(index); 184 assert(beg_index < len || len == 0, "index too large"); 185 186 const size_t stride = MIN2(len - beg_index, ObjArrayMarkingStride); 187 const size_t end_index = beg_index + stride; 188 T* const base = (T*)a->base(); 189 T* const beg = base + beg_index; 190 T* const end = base + end_index; 191 192 // Push the non-NULL elements of the next stride on the marking stack. 193 for (T* e = beg; e < end; e++) { 194 MarkSweep::mark_and_push<T>(e); 195 } 196 197 if (end_index < len) { 198 MarkSweep::push_objarray(a, end_index); // Push the continuation. 199 } 200 } 201 202 void ObjArrayKlass::oop_ms_follow_contents(oop obj) { 203 assert (obj->is_array(), "obj must be array"); 204 MarkSweep::follow_klass(this); 205 if (UseCompressedOops) { 206 oop_ms_follow_contents_specialized<narrowOop>(obj, 0); 207 } else { 208 oop_ms_follow_contents_specialized<oop>(obj, 0); 209 } 210 } 211 212 void TypeArrayKlass::oop_ms_follow_contents(oop obj) { 213 assert(obj->is_typeArray(),"must be a type array"); 214 // Performance tweak: We skip iterating over the klass pointer since we 215 // know that Universe::TypeArrayKlass never moves. 216 } 217 218 void MarkSweep::follow_array(objArrayOop array, int index) { 219 if (UseCompressedOops) { 220 oop_ms_follow_contents_specialized<narrowOop>(array, index); 221 } else { 222 oop_ms_follow_contents_specialized<oop>(array, index); 223 } 224 } 225 226 void MarkSweep::follow_stack() { 227 do { 228 while (!_marking_stack.is_empty()) { 229 oop obj = _marking_stack.pop(); 230 assert (obj->is_gc_marked(), "p must be marked"); 231 follow_object(obj); 232 } 233 // Process ObjArrays one at a time to avoid marking stack bloat. 234 if (!_objarray_stack.is_empty()) { 235 ObjArrayTask task = _objarray_stack.pop(); 236 follow_array(objArrayOop(task.obj()), task.index()); 237 } 238 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty()); 239 } 240 241 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure; 242 243 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); } 244 245 void PreservedMark::adjust_pointer() { 246 MarkSweep::adjust_pointer(&_obj); 247 } 248 249 void PreservedMark::restore() { 250 _obj->set_mark(_mark); 251 } 252 253 // We preserve the mark which should be replaced at the end and the location 254 // that it will go. Note that the object that this markOop belongs to isn't 255 // currently at that address but it will be after phase4 256 void MarkSweep::preserve_mark(oop obj, markOop mark) { 257 // We try to store preserved marks in the to space of the new generation since 258 // this is storage which should be available. Most of the time this should be 259 // sufficient space for the marks we need to preserve but if it isn't we fall 260 // back to using Stacks to keep track of the overflow. 261 if (_preserved_count < _preserved_count_max) { 262 _preserved_marks[_preserved_count++].init(obj, mark); 263 } else { 264 _preserved_mark_stack.push(mark); 265 _preserved_oop_stack.push(obj); 266 } 267 } 268 269 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure; 270 271 template <typename T> 272 void MarkSweep::AdjustPointerClosure::do_oop_nv(T* p) { adjust_pointer(p); } 273 void MarkSweep::AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); } 274 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 275 276 void MarkSweep::adjust_marks() { 277 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(), 278 "inconsistent preserved oop stacks"); 279 280 // adjust the oops we saved earlier 281 for (size_t i = 0; i < _preserved_count; i++) { 282 _preserved_marks[i].adjust_pointer(); 283 } 284 285 // deal with the overflow stack 286 StackIterator<oop, mtGC> iter(_preserved_oop_stack); 287 while (!iter.is_empty()) { 288 oop* p = iter.next_addr(); 289 adjust_pointer(p); 290 } 291 } 292 293 void MarkSweep::restore_marks() { 294 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(), 295 "inconsistent preserved oop stacks"); 296 if (PrintGC && Verbose) { 297 gclog_or_tty->print_cr("Restoring " SIZE_FORMAT " marks", 298 _preserved_count + _preserved_oop_stack.size()); 299 } 300 301 // restore the marks we saved earlier 302 for (size_t i = 0; i < _preserved_count; i++) { 303 _preserved_marks[i].restore(); 304 } 305 306 // deal with the overflow 307 while (!_preserved_oop_stack.is_empty()) { 308 oop obj = _preserved_oop_stack.pop(); 309 markOop mark = _preserved_mark_stack.pop(); 310 obj->set_mark(mark); 311 } 312 } 313 314 MarkSweep::IsAliveClosure MarkSweep::is_alive; 315 316 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); } 317 318 MarkSweep::KeepAliveClosure MarkSweep::keep_alive; 319 320 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 321 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 322 323 void marksweep_init() { 324 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer(); 325 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer(); 326 } 327 328 int InstanceKlass::oop_ms_adjust_pointers(oop obj) { 329 int size = size_helper(); 330 oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::adjust_pointer_closure); 331 return size; 332 } 333 334 int InstanceMirrorKlass::oop_ms_adjust_pointers(oop obj) { 335 int size = oop_size(obj); 336 InstanceKlass::oop_ms_adjust_pointers(obj); 337 338 oop_oop_iterate_statics<true>(obj, &MarkSweep::adjust_pointer_closure); 339 return size; 340 } 341 342 int InstanceClassLoaderKlass::oop_ms_adjust_pointers(oop obj) { 343 return InstanceKlass::oop_ms_adjust_pointers(obj); 344 } 345 346 #ifdef ASSERT 347 template <class T> static void trace_reference_gc(const char *s, oop obj, 348 T* referent_addr, 349 T* next_addr, 350 T* discovered_addr) { 351 if(TraceReferenceGC && PrintGCDetails) { 352 gclog_or_tty->print_cr("%s obj " PTR_FORMAT, s, p2i(obj)); 353 gclog_or_tty->print_cr(" referent_addr/* " PTR_FORMAT " / " 354 PTR_FORMAT, p2i(referent_addr), 355 p2i(referent_addr ? 356 (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL)); 357 gclog_or_tty->print_cr(" next_addr/* " PTR_FORMAT " / " 358 PTR_FORMAT, p2i(next_addr), 359 p2i(next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL)); 360 gclog_or_tty->print_cr(" discovered_addr/* " PTR_FORMAT " / " 361 PTR_FORMAT, p2i(discovered_addr), 362 p2i(discovered_addr ? 363 (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL)); 364 } 365 } 366 #endif 367 368 template <class T> void static adjust_object_specialized(oop obj) { 369 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); 370 MarkSweep::adjust_pointer(referent_addr); 371 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); 372 MarkSweep::adjust_pointer(next_addr); 373 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); 374 MarkSweep::adjust_pointer(discovered_addr); 375 debug_only(trace_reference_gc("InstanceRefKlass::oop_ms_adjust_pointers", obj, 376 referent_addr, next_addr, discovered_addr);) 377 } 378 379 int InstanceRefKlass::oop_ms_adjust_pointers(oop obj) { 380 int size = size_helper(); 381 InstanceKlass::oop_ms_adjust_pointers(obj); 382 383 if (UseCompressedOops) { 384 adjust_object_specialized<narrowOop>(obj); 385 } else { 386 adjust_object_specialized<oop>(obj); 387 } 388 return size; 389 } 390 391 int ObjArrayKlass::oop_ms_adjust_pointers(oop obj) { 392 assert(obj->is_objArray(), "obj must be obj array"); 393 objArrayOop a = objArrayOop(obj); 394 // Get size before changing pointers. 395 // Don't call size() or oop_size() since that is a virtual call. 396 int size = a->object_size(); 397 oop_oop_iterate_elements<true>(a, &MarkSweep::adjust_pointer_closure); 398 return size; 399 } 400 401 int TypeArrayKlass::oop_ms_adjust_pointers(oop obj) { 402 assert(obj->is_typeArray(), "must be a type array"); 403 typeArrayOop t = typeArrayOop(obj); 404 // Performance tweak: We skip iterating over the klass pointer since we 405 // know that Universe::TypeArrayKlass never moves. 406 return t->object_size(); 407 }