1 /* 2 * Copyright (c) 2014, 2016, 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 "code/codeCache.hpp" 27 #include "code/nmethod.hpp" 28 #include "gc/g1/g1CodeRootSetTable.hpp" 29 #include "gc/g1/g1CodeCacheRemSet.hpp" 30 #include "gc/g1/heapRegion.hpp" 31 #include "memory/heap.hpp" 32 #include "memory/iterator.hpp" 33 #include "oops/oop.inline.hpp" 34 #include "utilities/hashtable.inline.hpp" 35 #include "utilities/stack.inline.hpp" 36 37 G1CodeRootSetTable* volatile G1CodeRootSetTable::_purge_list = NULL; 38 39 size_t G1CodeRootSetTable::mem_size() { 40 return sizeof(G1CodeRootSetTable) + (entry_size() * number_of_entries()) + (sizeof(HashtableBucket<mtGC>) * table_size()); 41 } 42 43 G1CodeRootSetTable::Entry* G1CodeRootSetTable::new_entry(nmethod* nm) { 44 unsigned int hash = compute_hash(nm); 45 Entry* entry = (Entry*) new_entry_free_list(); 46 if (entry == NULL) { 47 entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC); 48 } 49 entry->set_next(NULL); 50 entry->set_hash(hash); 51 entry->set_literal(nm); 52 return entry; 53 } 54 55 void G1CodeRootSetTable::remove_entry(Entry* e, Entry* previous) { 56 int index = hash_to_index(e->hash()); 57 assert((e == bucket(index)) == (previous == NULL), "if e is the first entry then previous should be null"); 58 59 if (previous == NULL) { 60 set_entry(index, e->next()); 61 } else { 62 previous->set_next(e->next()); 63 } 64 free_entry(e); 65 } 66 67 G1CodeRootSetTable::~G1CodeRootSetTable() { 68 for (int index = 0; index < table_size(); ++index) { 69 for (Entry* e = bucket(index); e != NULL; ) { 70 Entry* to_remove = e; 71 // read next before freeing. 72 e = e->next(); 73 unlink_entry(to_remove); 74 FREE_C_HEAP_ARRAY(char, to_remove); 75 } 76 } 77 assert(number_of_entries() == 0, "should have removed all entries"); 78 free_buckets(); 79 for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) { 80 FREE_C_HEAP_ARRAY(char, e); 81 } 82 } 83 84 bool G1CodeRootSetTable::add(nmethod* nm) { 85 if (!contains(nm)) { 86 Entry* e = new_entry(nm); 87 int index = hash_to_index(e->hash()); 88 add_entry(index, e); 89 return true; 90 } 91 return false; 92 } 93 94 bool G1CodeRootSetTable::contains(nmethod* nm) { 95 int index = hash_to_index(compute_hash(nm)); 96 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 97 if (e->literal() == nm) { 98 return true; 99 } 100 } 101 return false; 102 } 103 104 bool G1CodeRootSetTable::remove(nmethod* nm) { 105 int index = hash_to_index(compute_hash(nm)); 106 Entry* previous = NULL; 107 for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) { 108 if (e->literal() == nm) { 109 remove_entry(e, previous); 110 return true; 111 } 112 } 113 return false; 114 } 115 116 void G1CodeRootSetTable::copy_to(G1CodeRootSetTable* new_table) { 117 for (int index = 0; index < table_size(); ++index) { 118 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 119 new_table->add(e->literal()); 120 } 121 } 122 new_table->copy_freelist(this); 123 } 124 125 void G1CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) { 126 for (int index = 0; index < table_size(); ++index) { 127 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 128 blk->do_code_blob(e->literal()); 129 } 130 } 131 } 132 133 template<typename CB> 134 int G1CodeRootSetTable::remove_if(CB& should_remove) { 135 int num_removed = 0; 136 for (int index = 0; index < table_size(); ++index) { 137 Entry* previous = NULL; 138 Entry* e = bucket(index); 139 while (e != NULL) { 140 Entry* next = e->next(); 141 if (should_remove(e->literal())) { 142 remove_entry(e, previous); 143 ++num_removed; 144 } else { 145 previous = e; 146 } 147 e = next; 148 } 149 } 150 return num_removed; 151 } 152 153 G1CodeRootSet::~G1CodeRootSet() { 154 delete _table; 155 } 156 157 G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() { 158 return (G1CodeRootSetTable*) OrderAccess::load_ptr_acquire(&_table); 159 } 160 161 void G1CodeRootSet::allocate_small_table() { 162 G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize); 163 164 OrderAccess::release_store_ptr(&_table, temp); 165 } 166 167 void G1CodeRootSetTable::purge_list_append(G1CodeRootSetTable* table) { 168 for (;;) { 169 table->_purge_next = _purge_list; 170 G1CodeRootSetTable* old = (G1CodeRootSetTable*) Atomic::cmpxchg_ptr(table, &_purge_list, table->_purge_next); 171 if (old == table->_purge_next) { 172 break; 173 } 174 } 175 } 176 177 void G1CodeRootSetTable::purge() { 178 G1CodeRootSetTable* table = _purge_list; 179 _purge_list = NULL; 180 while (table != NULL) { 181 G1CodeRootSetTable* to_purge = table; 182 table = table->_purge_next; 183 delete to_purge; 184 } 185 } 186 187 void G1CodeRootSet::move_to_large() { 188 G1CodeRootSetTable* temp = new G1CodeRootSetTable(LargeSize); 189 190 _table->copy_to(temp); 191 192 G1CodeRootSetTable::purge_list_append(_table); 193 194 OrderAccess::release_store_ptr(&_table, temp); 195 } 196 197 void G1CodeRootSet::purge() { 198 G1CodeRootSetTable::purge(); 199 } 200 201 size_t G1CodeRootSet::static_mem_size() { 202 return G1CodeRootSetTable::static_mem_size(); 203 } 204 205 void G1CodeRootSet::add(nmethod* method) { 206 bool added = false; 207 if (is_empty()) { 208 allocate_small_table(); 209 } 210 added = _table->add(method); 211 if (added) { 212 if (_length == Threshold) { 213 move_to_large(); 214 } 215 ++_length; 216 } 217 assert(_length == (size_t)_table->number_of_entries(), "sizes should match"); 218 } 219 220 bool G1CodeRootSet::remove(nmethod* method) { 221 bool removed = false; 222 if (_table != NULL) { 223 removed = _table->remove(method); 224 } 225 if (removed) { 226 _length--; 227 if (_length == 0) { 228 clear(); 229 } 230 } 231 assert((_length == 0 && _table == NULL) || 232 (_length == (size_t)_table->number_of_entries()), "sizes should match"); 233 return removed; 234 } 235 236 bool G1CodeRootSet::contains(nmethod* method) { 237 G1CodeRootSetTable* table = load_acquire_table(); // contains() may be called outside of lock, so ensure mem sync. 238 if (table != NULL) { 239 return table->contains(method); 240 } 241 return false; 242 } 243 244 void G1CodeRootSet::clear() { 245 delete _table; 246 _table = NULL; 247 _length = 0; 248 } 249 250 size_t G1CodeRootSet::mem_size() { 251 return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0); 252 } 253 254 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const { 255 if (_table != NULL) { 256 _table->nmethods_do(blk); 257 } 258 } 259 260 class CleanCallback : public StackObj { 261 class PointsIntoHRDetectionClosure : public OopClosure { 262 HeapRegion* _hr; 263 public: 264 bool _points_into; 265 PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {} 266 267 void do_oop(narrowOop* o) { 268 do_oop_work(o); 269 } 270 271 void do_oop(oop* o) { 272 do_oop_work(o); 273 } 274 275 template <typename T> 276 void do_oop_work(T* p) { 277 if (_hr->is_in(oopDesc::load_decode_heap_oop(p))) { 278 _points_into = true; 279 } 280 } 281 }; 282 283 PointsIntoHRDetectionClosure _detector; 284 CodeBlobToOopClosure _blobs; 285 286 public: 287 CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {} 288 289 bool operator() (nmethod* nm) { 290 _detector._points_into = false; 291 _blobs.do_code_blob(nm); 292 return !_detector._points_into; 293 } 294 }; 295 296 void G1CodeRootSet::clean(HeapRegion* owner) { 297 CleanCallback should_clean(owner); 298 if (_table != NULL) { 299 int removed = _table->remove_if(should_clean); 300 assert((size_t)removed <= _length, "impossible"); 301 _length -= removed; 302 } 303 if (_length == 0) { 304 clear(); 305 } 306 }