1 /* 2 * Copyright (c) 2001, 2020, 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 #ifndef SHARE_MEMORY_BINARYTREEDICTIONARY_HPP 26 #define SHARE_MEMORY_BINARYTREEDICTIONARY_HPP 27 28 #include "memory/freeList.hpp" 29 #include "memory/memRegion.hpp" 30 31 class Mutex; 32 33 /* 34 * A binary tree based search structure for free blocks. 35 * This is currently used in the Concurrent Mark&Sweep implementation, but 36 * will be used for free block management for metadata. 37 */ 38 39 // A TreeList is a FreeList which can be used to maintain a 40 // binary tree of free lists. 41 42 template <class Chunk_t, class FreeList_t> class TreeChunk; 43 template <class Chunk_t, class FreeList_t> class BinaryTreeDictionary; 44 template <class Chunk_t, class FreeList_t> class AscendTreeCensusClosure; 45 template <class Chunk_t, class FreeList_t> class DescendTreeCensusClosure; 46 template <class Chunk_t, class FreeList_t> class DescendTreeSearchClosure; 47 48 template <class Chunk_t, class FreeList_t> 49 class TreeList : public FreeList_t { 50 friend class TreeChunk<Chunk_t, FreeList_t>; 51 friend class BinaryTreeDictionary<Chunk_t, FreeList_t>; 52 friend class AscendTreeCensusClosure<Chunk_t, FreeList_t>; 53 friend class DescendTreeCensusClosure<Chunk_t, FreeList_t>; 54 friend class DescendTreeSearchClosure<Chunk_t, FreeList_t>; 55 56 TreeList<Chunk_t, FreeList_t>* _parent; 57 TreeList<Chunk_t, FreeList_t>* _left; 58 TreeList<Chunk_t, FreeList_t>* _right; 59 60 protected: 61 62 TreeList<Chunk_t, FreeList_t>* parent() const { return _parent; } 63 TreeList<Chunk_t, FreeList_t>* left() const { return _left; } 64 TreeList<Chunk_t, FreeList_t>* right() const { return _right; } 65 66 // Wrapper on call to base class, to get the template to compile. 67 Chunk_t* head() const { return FreeList_t::head(); } 68 Chunk_t* tail() const { return FreeList_t::tail(); } 69 void set_head(Chunk_t* head) { FreeList_t::set_head(head); } 70 void set_tail(Chunk_t* tail) { FreeList_t::set_tail(tail); } 71 72 size_t size() const { return FreeList_t::size(); } 73 74 // Accessors for links in tree. 75 76 void set_left(TreeList<Chunk_t, FreeList_t>* tl) { 77 _left = tl; 78 if (tl != NULL) 79 tl->set_parent(this); 80 } 81 void set_right(TreeList<Chunk_t, FreeList_t>* tl) { 82 _right = tl; 83 if (tl != NULL) 84 tl->set_parent(this); 85 } 86 void set_parent(TreeList<Chunk_t, FreeList_t>* tl) { _parent = tl; } 87 88 void clear_left() { _left = NULL; } 89 void clear_right() { _right = NULL; } 90 void clear_parent() { _parent = NULL; } 91 void initialize() { clear_left(); clear_right(), clear_parent(); FreeList_t::initialize(); } 92 93 // For constructing a TreeList from a Tree chunk or 94 // address and size. 95 TreeList(); 96 static TreeList<Chunk_t, FreeList_t>* 97 as_TreeList(TreeChunk<Chunk_t, FreeList_t>* tc); 98 static TreeList<Chunk_t, FreeList_t>* as_TreeList(HeapWord* addr, size_t size); 99 100 // Returns the head of the free list as a pointer to a TreeChunk. 101 TreeChunk<Chunk_t, FreeList_t>* head_as_TreeChunk(); 102 103 // Returns the first available chunk in the free list as a pointer 104 // to a TreeChunk. 105 TreeChunk<Chunk_t, FreeList_t>* first_available(); 106 107 // Returns the block with the largest heap address amongst 108 // those in the list for this size; potentially slow and expensive, 109 // use with caution! 110 TreeChunk<Chunk_t, FreeList_t>* largest_address(); 111 112 TreeList<Chunk_t, FreeList_t>* get_better_list( 113 BinaryTreeDictionary<Chunk_t, FreeList_t>* dictionary); 114 115 // remove_chunk_replace_if_needed() removes the given "tc" from the TreeList. 116 // If "tc" is the first chunk in the list, it is also the 117 // TreeList that is the node in the tree. remove_chunk_replace_if_needed() 118 // returns the possibly replaced TreeList* for the node in 119 // the tree. It also updates the parent of the original 120 // node to point to the new node. 121 TreeList<Chunk_t, FreeList_t>* remove_chunk_replace_if_needed(TreeChunk<Chunk_t, FreeList_t>* tc); 122 // See FreeList. 123 void return_chunk_at_tail(TreeChunk<Chunk_t, FreeList_t>* tc); 124 }; 125 126 // A TreeChunk is a subclass of a Chunk that additionally 127 // maintains a pointer to the free list on which it is currently 128 // linked. 129 // A TreeChunk is also used as a node in the binary tree. This 130 // allows the binary tree to be maintained without any additional 131 // storage (the free chunks are used). In a binary tree the first 132 // chunk in the free list is also the tree node. Note that the 133 // TreeChunk has an embedded TreeList for this purpose. Because 134 // the first chunk in the list is distinguished in this fashion 135 // (also is the node in the tree), it is the last chunk to be found 136 // on the free list for a node in the tree and is only removed if 137 // it is the last chunk on the free list. 138 139 template <class Chunk_t, class FreeList_t> 140 class TreeChunk : public Chunk_t { 141 friend class TreeList<Chunk_t, FreeList_t>; 142 TreeList<Chunk_t, FreeList_t>* _list; 143 TreeList<Chunk_t, FreeList_t> _embedded_list; // if non-null, this chunk is on _list 144 145 static size_t _min_tree_chunk_size; 146 147 protected: 148 TreeList<Chunk_t, FreeList_t>* embedded_list() const { return (TreeList<Chunk_t, FreeList_t>*) &_embedded_list; } 149 void set_embedded_list(TreeList<Chunk_t, FreeList_t>* v) { _embedded_list = *v; } 150 public: 151 TreeList<Chunk_t, FreeList_t>* list() { return _list; } 152 void set_list(TreeList<Chunk_t, FreeList_t>* v) { _list = v; } 153 static TreeChunk<Chunk_t, FreeList_t>* as_TreeChunk(Chunk_t* fc); 154 // Initialize fields in a TreeChunk that should be 155 // initialized when the TreeChunk is being added to 156 // a free list in the tree. 157 void initialize() { embedded_list()->initialize(); } 158 159 Chunk_t* next() const { return Chunk_t::next(); } 160 Chunk_t* prev() const { return Chunk_t::prev(); } 161 size_t size() const { return Chunk_t::size(); } 162 163 static size_t min_size(); 164 165 // debugging 166 void verify_tree_chunk_list() const; 167 void assert_is_mangled() const; 168 }; 169 170 template <class Chunk_t, class FreeList_t> 171 size_t TreeChunk<Chunk_t, FreeList_t>::_min_tree_chunk_size = sizeof(TreeChunk<Chunk_t, FreeList_t>)/HeapWordSize; 172 template <class Chunk_t, class FreeList_t> 173 size_t TreeChunk<Chunk_t, FreeList_t>::min_size() { return _min_tree_chunk_size; } 174 175 template <class Chunk_t, class FreeList_t> 176 class BinaryTreeDictionary: public CHeapObj<mtGC> { 177 friend class VMStructs; 178 179 protected: 180 size_t _total_size; 181 size_t _total_free_blocks; 182 TreeList<Chunk_t, FreeList_t>* _root; 183 184 // private accessors 185 void set_total_size(size_t v) { _total_size = v; } 186 void inc_total_size(size_t v); 187 void dec_total_size(size_t v); 188 void set_total_free_blocks(size_t v) { _total_free_blocks = v; } 189 TreeList<Chunk_t, FreeList_t>* root() const { return _root; } 190 void set_root(TreeList<Chunk_t, FreeList_t>* v) { _root = v; } 191 192 // This field is added and can be set to point to the 193 // the Mutex used to synchronize access to the 194 // dictionary so that assertion checking can be done. 195 // For example it is set to point to _parDictionaryAllocLock. 196 NOT_PRODUCT(Mutex* _lock;) 197 198 // Remove a chunk of size "size" or larger from the tree and 199 // return it. If the chunk 200 // is the last chunk of that size, remove the node for that size 201 // from the tree. 202 TreeChunk<Chunk_t, FreeList_t>* get_chunk_from_tree(size_t size); 203 // Remove this chunk from the tree. If the removal results 204 // in an empty list in the tree, remove the empty list. 205 TreeChunk<Chunk_t, FreeList_t>* remove_chunk_from_tree(TreeChunk<Chunk_t, FreeList_t>* tc); 206 // Remove the node in the trees starting at tl that has the 207 // minimum value and return it. Repair the tree as needed. 208 TreeList<Chunk_t, FreeList_t>* remove_tree_minimum(TreeList<Chunk_t, FreeList_t>* tl); 209 // Add this free chunk to the tree. 210 void insert_chunk_in_tree(Chunk_t* freeChunk); 211 public: 212 213 // Return a list of the specified size or NULL from the tree. 214 // The list is not removed from the tree. 215 TreeList<Chunk_t, FreeList_t>* find_list (size_t size) const; 216 217 void verify_tree() const; 218 // verify that the given chunk is in the tree. 219 bool verify_chunk_in_free_list(Chunk_t* tc) const; 220 private: 221 void verify_tree_helper(TreeList<Chunk_t, FreeList_t>* tl) const; 222 static size_t verify_prev_free_ptrs(TreeList<Chunk_t, FreeList_t>* tl); 223 224 // Returns the total number of chunks in the list. 225 size_t total_list_length(TreeList<Chunk_t, FreeList_t>* tl) const; 226 // Returns the total number of words in the chunks in the tree 227 // starting at "tl". 228 size_t total_size_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const; 229 // Returns the sum of the square of the size of each block 230 // in the tree starting at "tl". 231 double sum_of_squared_block_sizes(TreeList<Chunk_t, FreeList_t>* const tl) const; 232 // Returns the total number of free blocks in the tree starting 233 // at "tl". 234 size_t total_free_blocks_in_tree(TreeList<Chunk_t, FreeList_t>* tl) const; 235 size_t num_free_blocks() const; 236 size_t tree_height() const; 237 size_t tree_height_helper(TreeList<Chunk_t, FreeList_t>* tl) const; 238 size_t total_nodes_helper(TreeList<Chunk_t, FreeList_t>* tl) const; 239 240 public: 241 // Constructor 242 BinaryTreeDictionary() : 243 _total_size(0), _total_free_blocks(0), _root(0) {} 244 245 BinaryTreeDictionary(MemRegion mr); 246 247 // Public accessors 248 size_t total_size() const { return _total_size; } 249 size_t total_free_blocks() const { return _total_free_blocks; } 250 251 // Reset the dictionary to the initial conditions with 252 // a single free chunk. 253 void reset(MemRegion mr); 254 void reset(HeapWord* addr, size_t size); 255 // Reset the dictionary to be empty. 256 void reset(); 257 258 // Return a chunk of size "size" or greater from 259 // the tree. 260 Chunk_t* get_chunk(size_t size) { 261 verify_par_locked(); 262 Chunk_t* res = get_chunk_from_tree(size); 263 assert(res == NULL || res->is_free(), 264 "Should be returning a free chunk"); 265 return res; 266 } 267 268 void return_chunk(Chunk_t* chunk) { 269 verify_par_locked(); 270 insert_chunk_in_tree(chunk); 271 } 272 273 void remove_chunk(Chunk_t* chunk) { 274 verify_par_locked(); 275 remove_chunk_from_tree((TreeChunk<Chunk_t, FreeList_t>*)chunk); 276 assert(chunk->is_free(), "Should still be a free chunk"); 277 } 278 279 size_t max_chunk_size() const; 280 inline size_t total_chunk_size(debug_only(const Mutex* lock)) const; 281 282 size_t min_size() const { 283 return TreeChunk<Chunk_t, FreeList_t>::min_size(); 284 } 285 286 double sum_of_squared_block_sizes() const { 287 return sum_of_squared_block_sizes(root()); 288 } 289 290 Chunk_t* find_chunk_ends_at(HeapWord* target) const; 291 292 // Return the largest free chunk in the tree. 293 Chunk_t* find_largest_dict() const; 294 295 void print_free_lists(outputStream* st) const; 296 297 // For debugging. Returns the sum of the _returned_bytes for 298 // all lists in the tree. 299 size_t sum_dict_returned_bytes() PRODUCT_RETURN0; 300 // Sets the _returned_bytes for all the lists in the tree to zero. 301 void initialize_dict_returned_bytes() PRODUCT_RETURN; 302 // For debugging. Return the total number of chunks in the dictionary. 303 size_t total_count() PRODUCT_RETURN0; 304 305 void report_statistics(outputStream* st) const; 306 307 void verify() const; 308 309 Mutex* par_lock() const PRODUCT_RETURN0; 310 void set_par_lock(Mutex* lock) PRODUCT_RETURN; 311 void verify_par_locked() const PRODUCT_RETURN; 312 }; 313 314 315 // Closures for walking the binary tree. 316 // do_list() walks the free list in a node applying the closure 317 // to each free chunk in the list 318 // do_tree() walks the nodes in the binary tree applying do_list() 319 // to each list at each node. 320 321 template <class Chunk_t, class FreeList_t> 322 class TreeCensusClosure : public StackObj { 323 protected: 324 virtual void do_list(FreeList_t* fl) = 0; 325 public: 326 virtual void do_tree(TreeList<Chunk_t, FreeList_t>* tl) = 0; 327 }; 328 329 template <class Chunk_t, class FreeList_t> 330 class AscendTreeCensusClosure : public TreeCensusClosure<Chunk_t, FreeList_t> { 331 public: 332 void do_tree(TreeList<Chunk_t, FreeList_t>* tl) { 333 if (tl != NULL) { 334 do_tree(tl->left()); 335 this->do_list(tl); 336 do_tree(tl->right()); 337 } 338 } 339 }; 340 341 template <class Chunk_t, class FreeList_t> 342 class DescendTreeCensusClosure : public TreeCensusClosure<Chunk_t, FreeList_t> { 343 public: 344 void do_tree(TreeList<Chunk_t, FreeList_t>* tl) { 345 if (tl != NULL) { 346 do_tree(tl->right()); 347 this->do_list(tl); 348 do_tree(tl->left()); 349 } 350 } 351 }; 352 353 // Used to search the tree until a condition is met. 354 // Similar to TreeCensusClosure but searches the 355 // tree and returns promptly when found. 356 357 template <class Chunk_t, class FreeList_t> 358 class TreeSearchClosure : public StackObj { 359 protected: 360 virtual bool do_list(FreeList_t* fl) = 0; 361 public: 362 virtual bool do_tree(TreeList<Chunk_t, FreeList_t>* tl) = 0; 363 }; 364 365 #if 0 // Don't need this yet but here for symmetry. 366 template <class Chunk_t, class FreeList_t> 367 class AscendTreeSearchClosure : public TreeSearchClosure<Chunk_t> { 368 public: 369 bool do_tree(TreeList<Chunk_t, FreeList_t>* tl) { 370 if (tl != NULL) { 371 if (do_tree(tl->left())) return true; 372 if (do_list(tl)) return true; 373 if (do_tree(tl->right())) return true; 374 } 375 return false; 376 } 377 }; 378 #endif 379 380 template <class Chunk_t, class FreeList_t> 381 class DescendTreeSearchClosure : public TreeSearchClosure<Chunk_t, FreeList_t> { 382 public: 383 bool do_tree(TreeList<Chunk_t, FreeList_t>* tl) { 384 if (tl != NULL) { 385 if (do_tree(tl->right())) return true; 386 if (this->do_list(tl)) return true; 387 if (do_tree(tl->left())) return true; 388 } 389 return false; 390 } 391 }; 392 393 #endif // SHARE_MEMORY_BINARYTREEDICTIONARY_HPP