1 /* 2 * Copyright (c) 2018, 2019, 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_METASPACE_BLOCKFREELIST_HPP 26 #define SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP 27 28 #include "memory/allocation.hpp" 29 #include "memory/binaryTreeDictionary.hpp" 30 #include "memory/freeList.hpp" 31 #include "memory/metaspace/smallBlocks.hpp" 32 #include "memory/metaspace/metablock.hpp" 33 #include "utilities/globalDefinitions.hpp" 34 35 namespace metaspace { 36 37 typedef BinaryTreeDictionary<Metablock, FreeList<Metablock> > BlockTreeDictionary; 38 39 // Used to manage the free list of Metablocks (a block corresponds 40 // to the allocation of a quantum of metadata). 41 class BlockFreelist : public CHeapObj<mtClass> { 42 43 BlockTreeDictionary* const _dictionary; 44 SmallBlocks* _small_blocks; 45 46 // Only allocate and split from freelist if the size of the allocation 47 // is at least 1/4th the size of the available block. 48 const static int WasteMultiplier = 4; 49 50 // Accessors 51 BlockTreeDictionary* dictionary() const { return _dictionary; } 52 SmallBlocks* small_blocks() { 53 if (_small_blocks == NULL) { 54 _small_blocks = new SmallBlocks(); 55 } 56 return _small_blocks; 57 } 58 59 public: 60 61 BlockFreelist(); 62 ~BlockFreelist(); 63 64 // Get and return a block to the free list 65 MetaWord* get_block(size_t word_size); 66 void return_block(MetaWord* p, size_t word_size); 67 68 // Returns the total size, in words, of all blocks kept in this structure. 69 size_t total_size() const { 70 size_t result = dictionary()->total_size(); 71 if (_small_blocks != NULL) { 72 result = result + _small_blocks->total_size(); 73 } 74 return result; 75 } 76 77 // Returns the number of all blocks kept in this structure. 78 uintx num_blocks() const { 79 uintx result = dictionary()->total_free_blocks(); 80 if (_small_blocks != NULL) { 81 result = result + _small_blocks->total_num_blocks(); 82 } 83 return result; 84 } 85 86 static size_t min_dictionary_size() { return TreeChunk<Metablock, FreeList<Metablock> >::min_size(); } 87 void print_on(outputStream* st) const; 88 }; 89 90 } // namespace metaspace 91 92 #endif // SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP