1 /* 2 * Copyright (c) 2014, 2017, 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/access.inline.hpp" 34 #include "oops/oop.inline.hpp" 35 #include "utilities/hashtable.inline.hpp" 36 #include "utilities/stack.inline.hpp" 37 38 G1CodeRootSetTable* volatile G1CodeRootSetTable::_purge_list = NULL; 39 40 size_t G1CodeRootSetTable::mem_size() { 41 return sizeof(G1CodeRootSetTable) + (entry_size() * number_of_entries()) + (sizeof(HashtableBucket<mtGC>) * table_size()); 42 } 43 44 G1CodeRootSetTable::Entry* G1CodeRootSetTable::new_entry(nmethod* nm) { 45 unsigned int hash = compute_hash(nm); 46 Entry* entry = (Entry*) new_entry_free_list(); 47 if (entry == NULL) { 48 entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC); 49 } 50 entry->set_next(NULL); 51 entry->set_hash(hash); 52 entry->set_literal(nm); 53 return entry; 54 } 55 56 void G1CodeRootSetTable::remove_entry(Entry* e, Entry* previous) { 57 int index = hash_to_index(e->hash()); 58 assert((e == bucket(index)) == (previous == NULL), "if e is the first entry then previous should be null"); 59 60 if (previous == NULL) { 61 set_entry(index, e->next()); 62 } else { 63 previous->set_next(e->next()); 64 } 65 free_entry(e); 66 } 67 68 G1CodeRootSetTable::~G1CodeRootSetTable() { 69 for (int index = 0; index < table_size(); ++index) { 70 for (Entry* e = bucket(index); e != NULL; ) { 71 Entry* to_remove = e; 72 // read next before freeing. 73 e = e->next(); 74 unlink_entry(to_remove); 75 FREE_C_HEAP_ARRAY(char, to_remove); 76 } 77 } 78 assert(number_of_entries() == 0, "should have removed all entries"); 79 free_buckets(); 80 for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) { 81 FREE_C_HEAP_ARRAY(char, e); 82 } 83 } 84 85 bool G1CodeRootSetTable::add(nmethod* nm) { 86 if (!contains(nm)) { 87 Entry* e = new_entry(nm); 88 int index = hash_to_index(e->hash()); 89 add_entry(index, e); 90 return true; 91 } 92 return false; 93 } 94 95 bool G1CodeRootSetTable::contains(nmethod* nm) { 96 int index = hash_to_index(compute_hash(nm)); 97 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 98 if (e->literal() == nm) { 99 return true; 100 } 101 } 102 return false; 103 } 104 105 bool G1CodeRootSetTable::remove(nmethod* nm) { 106 int index = hash_to_index(compute_hash(nm)); 107 Entry* previous = NULL; 108 for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) { 109 if (e->literal() == nm) { 110 remove_entry(e, previous); 111 return true; 112 } 113 } 114 return false; 115 } 116 117 void G1CodeRootSetTable::copy_to(G1CodeRootSetTable* new_table) { 118 for (int index = 0; index < table_size(); ++index) { 119 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 120 new_table->add(e->literal()); 121 } 122 } 123 new_table->copy_freelist(this); 124 } 125 126 void G1CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) { 127 for (int index = 0; index < table_size(); ++index) { 128 for (Entry* e = bucket(index); e != NULL; e = e->next()) { 129 blk->do_code_blob(e->literal()); 130 } 131 } 132 } 133 134 template<typename CB> 135 int G1CodeRootSetTable::remove_if(CB& should_remove) { 136 int num_removed = 0; 137 for (int index = 0; index < table_size(); ++index) { 138 Entry* previous = NULL; 139 Entry* e = bucket(index); 140 while (e != NULL) { 141 Entry* next = e->next(); 142 if (should_remove(e->literal())) { 143 remove_entry(e, previous); 144 ++num_removed; 145 } else { 146 previous = e; 147 } 148 e = next; 149 } 150 } 151 return num_removed; 152 } 153 154 G1CodeRootSet::~G1CodeRootSet() { 155 delete _table; 156 } 157 158 G1CodeRootSetTable* G1CodeRootSet::load_acquire_table() { 159 return OrderAccess::load_acquire(&_table); 160 } 161 162 void G1CodeRootSet::allocate_small_table() { 163 G1CodeRootSetTable* temp = new G1CodeRootSetTable(SmallSize); 164 165 OrderAccess::release_store(&_table, temp); 166 } 167 168 void G1CodeRootSetTable::purge_list_append(G1CodeRootSetTable* table) { 169 for (;;) { 170 table->_purge_next = _purge_list; 171 G1CodeRootSetTable* old = Atomic::cmpxchg(table, &_purge_list, table->_purge_next); 172 if (old == table->_purge_next) { 173 break; 174 } 175 } 176 } 177 178 void G1CodeRootSetTable::purge() { 179 G1CodeRootSetTable* table = _purge_list; 180 _purge_list = NULL; 181 while (table != NULL) { 182 G1CodeRootSetTable* to_purge = table; 183 table = table->_purge_next; 184 delete to_purge; 185 } 186 } 187 188 void G1CodeRootSet::move_to_large() { 189 G1CodeRootSetTable* temp = new G1CodeRootSetTable(LargeSize); 190 191 _table->copy_to(temp); 192 193 G1CodeRootSetTable::purge_list_append(_table); 194 195 OrderAccess::release_store(&_table, temp); 196 } 197 198 void G1CodeRootSet::purge() { 199 G1CodeRootSetTable::purge(); 200 } 201 202 size_t G1CodeRootSet::static_mem_size() { 203 return G1CodeRootSetTable::static_mem_size(); 204 } 205 206 void G1CodeRootSet::add(nmethod* method) { 207 bool added = false; 208 if (is_empty()) { 209 allocate_small_table(); 210 } 211 added = _table->add(method); 212 if (added) { 213 if (_length == Threshold) { 214 move_to_large(); 215 } 216 ++_length; 217 } 218 assert(_length == (size_t)_table->number_of_entries(), "sizes should match"); 219 } 220 221 bool G1CodeRootSet::remove(nmethod* method) { 222 bool removed = false; 223 if (_table != NULL) { 224 removed = _table->remove(method); 225 } 226 if (removed) { 227 _length--; 228 if (_length == 0) { 229 clear(); 230 } 231 } 232 assert((_length == 0 && _table == NULL) || 233 (_length == (size_t)_table->number_of_entries()), "sizes should match"); 234 return removed; 235 } 236 237 bool G1CodeRootSet::contains(nmethod* method) { 238 G1CodeRootSetTable* table = load_acquire_table(); // contains() may be called outside of lock, so ensure mem sync. 239 if (table != NULL) { 240 return table->contains(method); 241 } 242 return false; 243 } 244 245 void G1CodeRootSet::clear() { 246 delete _table; 247 _table = NULL; 248 _length = 0; 249 } 250 251 size_t G1CodeRootSet::mem_size() { 252 return sizeof(*this) + (_table != NULL ? _table->mem_size() : 0); 253 } 254 255 void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const { 256 if (_table != NULL) { 257 _table->nmethods_do(blk); 258 } 259 } 260 261 class CleanCallback : public StackObj { 262 class PointsIntoHRDetectionClosure : public OopClosure { 263 HeapRegion* _hr; 264 public: 265 bool _points_into; 266 PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {} 267 268 void do_oop(narrowOop* o) { 269 do_oop_work(o); 270 } 271 272 void do_oop(oop* o) { 273 do_oop_work(o); 274 } 275 276 template <typename T> 277 void do_oop_work(T* p) { 278 if (_hr->is_in(RawAccess<>::oop_load(p))) { 279 _points_into = true; 280 } 281 } 282 }; 283 284 PointsIntoHRDetectionClosure _detector; 285 CodeBlobToOopClosure _blobs; 286 287 public: 288 CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {} 289 290 bool operator() (nmethod* nm) { 291 _detector._points_into = false; 292 _blobs.do_code_blob(nm); 293 return !_detector._points_into; 294 } 295 }; 296 297 void G1CodeRootSet::clean(HeapRegion* owner) { 298 CleanCallback should_clean(owner); 299 if (_table != NULL) { 300 int removed = _table->remove_if(should_clean); 301 assert((size_t)removed <= _length, "impossible"); 302 _length -= removed; 303 } 304 if (_length == 0) { 305 clear(); 306 } 307 }