1 /* 2 * Copyright (c) 1997, 2018, 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/access.inline.hpp" 34 #include "oops/compressedOops.inline.hpp" 35 #include "oops/instanceClassLoaderKlass.inline.hpp" 36 #include "oops/instanceKlass.inline.hpp" 37 #include "oops/instanceMirrorKlass.inline.hpp" 38 #include "oops/instanceRefKlass.inline.hpp" 39 #include "oops/methodData.hpp" 40 #include "oops/objArrayKlass.inline.hpp" 41 #include "oops/oop.inline.hpp" 42 #include "oops/typeArrayOop.inline.hpp" 43 #include "utilities/macros.hpp" 44 #include "utilities/stack.inline.hpp" 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 // some marks may contain information we need to preserve so we store them away 68 // and overwrite the mark. We'll restore it at the end of markSweep. 69 markOop mark = obj->mark(); 70 obj->set_mark(markOopDesc::prototype()->set_marked()); 71 72 if (mark->must_be_preserved(obj)) { 73 preserve_mark(obj, mark); 74 } 75 } 76 77 template <class T> inline void MarkSweep::mark_and_push(T* p) { 78 T heap_oop = RawAccess<>::oop_load(p); 79 if (!CompressedOops::is_null(heap_oop)) { 80 oop obj = CompressedOops::decode_not_null(heap_oop); 81 if (!obj->mark()->is_marked()) { 82 mark_object(obj); 83 _marking_stack.push(obj); 84 } 85 } 86 } 87 88 inline void MarkSweep::follow_klass(Klass* klass) { 89 oop op = klass->klass_holder(); 90 MarkSweep::mark_and_push(&op); 91 } 92 93 inline void MarkSweep::follow_cld(ClassLoaderData* cld) { 94 MarkSweep::follow_cld_closure.do_cld(cld); 95 } 96 97 template <typename T> 98 inline void MarkAndPushClosure::do_oop_nv(T* p) { MarkSweep::mark_and_push(p); } 99 void MarkAndPushClosure::do_oop(oop* p) { do_oop_nv(p); } 100 void MarkAndPushClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 101 inline bool MarkAndPushClosure::do_metadata_nv() { return true; } 102 bool MarkAndPushClosure::do_metadata() { return do_metadata_nv(); } 103 inline void MarkAndPushClosure::do_klass_nv(Klass* k) { MarkSweep::follow_klass(k); } 104 void MarkAndPushClosure::do_klass(Klass* k) { do_klass_nv(k); } 105 inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); } 106 void MarkAndPushClosure::do_cld(ClassLoaderData* cld) { do_cld_nv(cld); } 107 108 template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) { 109 mark_and_push(p); 110 } 111 112 void MarkSweep::push_objarray(oop obj, size_t index) { 113 ObjArrayTask task(obj, index); 114 assert(task.is_valid(), "bad ObjArrayTask"); 115 _objarray_stack.push(task); 116 } 117 118 inline void MarkSweep::follow_array(objArrayOop array) { 119 MarkSweep::follow_klass(array->klass()); 120 // Don't push empty arrays to avoid unnecessary work. 121 if (array->length() > 0) { 122 MarkSweep::push_objarray(array, 0); 123 } 124 } 125 126 inline void MarkSweep::follow_object(oop obj) { 127 assert(obj->is_gc_marked(), "should be marked"); 128 if (obj->is_objArray()) { 129 // Handle object arrays explicitly to allow them to 130 // be split into chunks if needed. 131 MarkSweep::follow_array((objArrayOop)obj); 132 } else { 133 obj->oop_iterate(&mark_and_push_closure); 134 } 135 } 136 137 void MarkSweep::follow_array_chunk(objArrayOop array, int index) { 138 const int len = array->length(); 139 const int beg_index = index; 140 assert(beg_index < len || len == 0, "index too large"); 141 142 const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride); 143 const int end_index = beg_index + stride; 144 145 array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index); 146 147 if (end_index < len) { 148 MarkSweep::push_objarray(array, end_index); // Push the continuation. 149 } 150 } 151 152 void MarkSweep::follow_stack() { 153 do { 154 while (!_marking_stack.is_empty()) { 155 oop obj = _marking_stack.pop(); 156 assert (obj->is_gc_marked(), "p must be marked"); 157 follow_object(obj); 158 } 159 // Process ObjArrays one at a time to avoid marking stack bloat. 160 if (!_objarray_stack.is_empty()) { 161 ObjArrayTask task = _objarray_stack.pop(); 162 follow_array_chunk(objArrayOop(task.obj()), task.index()); 163 } 164 } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty()); 165 } 166 167 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure; 168 169 void MarkSweep::FollowStackClosure::do_void() { follow_stack(); } 170 171 template <class T> inline void MarkSweep::follow_root(T* p) { 172 assert(!Universe::heap()->is_in_reserved(p), 173 "roots shouldn't be things within the heap"); 174 T heap_oop = RawAccess<>::oop_load(p); 175 if (!CompressedOops::is_null(heap_oop)) { 176 oop obj = CompressedOops::decode_not_null(heap_oop); 177 if (!obj->mark()->is_marked()) { 178 mark_object(obj); 179 follow_object(obj); 180 } 181 } 182 follow_stack(); 183 } 184 185 void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); } 186 void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); } 187 188 void PreservedMark::adjust_pointer() { 189 MarkSweep::adjust_pointer(&_obj); 190 } 191 192 void PreservedMark::restore() { 193 _obj->set_mark(_mark); 194 } 195 196 // We preserve the mark which should be replaced at the end and the location 197 // that it will go. Note that the object that this markOop belongs to isn't 198 // currently at that address but it will be after phase4 199 void MarkSweep::preserve_mark(oop obj, markOop mark) { 200 // We try to store preserved marks in the to space of the new generation since 201 // this is storage which should be available. Most of the time this should be 202 // sufficient space for the marks we need to preserve but if it isn't we fall 203 // back to using Stacks to keep track of the overflow. 204 if (_preserved_count < _preserved_count_max) { 205 _preserved_marks[_preserved_count++].init(obj, mark); 206 } else { 207 _preserved_mark_stack.push(mark); 208 _preserved_oop_stack.push(obj); 209 } 210 } 211 212 void MarkSweep::set_ref_processor(ReferenceProcessor* rp) { 213 _ref_processor = rp; 214 mark_and_push_closure.set_ref_discoverer(_ref_processor); 215 } 216 217 AdjustPointerClosure MarkSweep::adjust_pointer_closure; 218 219 template <typename T> 220 void AdjustPointerClosure::do_oop_nv(T* p) { MarkSweep::adjust_pointer(p); } 221 void AdjustPointerClosure::do_oop(oop* p) { do_oop_nv(p); } 222 void AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 223 224 void MarkSweep::adjust_marks() { 225 assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(), 226 "inconsistent preserved oop stacks"); 227 228 // adjust the oops we saved earlier 229 for (size_t i = 0; i < _preserved_count; i++) { 230 _preserved_marks[i].adjust_pointer(); 231 } 232 233 // deal with the overflow stack 234 StackIterator<oop, mtGC> iter(_preserved_oop_stack); 235 while (!iter.is_empty()) { 236 oop* p = iter.next_addr(); 237 adjust_pointer(p); 238 } 239 } 240 241 void MarkSweep::restore_marks() { 242 assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(), 243 "inconsistent preserved oop stacks"); 244 log_trace(gc)("Restoring " SIZE_FORMAT " marks", _preserved_count + _preserved_oop_stack.size()); 245 246 // restore the marks we saved earlier 247 for (size_t i = 0; i < _preserved_count; i++) { 248 _preserved_marks[i].restore(); 249 } 250 251 // deal with the overflow 252 while (!_preserved_oop_stack.is_empty()) { 253 oop obj = _preserved_oop_stack.pop(); 254 markOop mark = _preserved_mark_stack.pop(); 255 obj->set_mark(mark); 256 } 257 } 258 259 MarkSweep::IsAliveClosure MarkSweep::is_alive; 260 261 bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); } 262 263 MarkSweep::KeepAliveClosure MarkSweep::keep_alive; 264 265 void MarkSweep::KeepAliveClosure::do_oop(oop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 266 void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); } 267 268 void marksweep_init() { 269 MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer(); 270 MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer(); 271 } 272 273 // Generate MS specialized oop_oop_iterate functions. 274 SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)