1 /* 2 * Copyright (c) 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 #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 namespace internals { 37 38 typedef BinaryTreeDictionary<Metablock, FreeList<Metablock> > BlockTreeDictionary; 39 40 // Used to manage the free list of Metablocks (a block corresponds 41 // to the allocation of a quantum of metadata). 42 class BlockFreelist : public CHeapObj<mtClass> { 43 44 BlockTreeDictionary* const _dictionary; 45 SmallBlocks* _small_blocks; 46 47 // Only allocate and split from freelist if the size of the allocation 48 // is at least 1/4th the size of the available block. 49 const static int WasteMultiplier = 4; 50 51 // Accessors 52 BlockTreeDictionary* dictionary() const { return _dictionary; } 53 SmallBlocks* small_blocks() { 54 if (_small_blocks == NULL) { 55 _small_blocks = new SmallBlocks(); 56 } 57 return _small_blocks; 58 } 59 60 public: 61 62 BlockFreelist(); 63 ~BlockFreelist(); 64 65 // Get and return a block to the free list 66 MetaWord* get_block(size_t word_size); 67 void return_block(MetaWord* p, size_t word_size); 68 69 // Returns the total size, in words, of all blocks kept in this structure. 70 size_t total_size() const { 71 size_t result = dictionary()->total_size(); 72 if (_small_blocks != NULL) { 73 result = result + _small_blocks->total_size(); 74 } 75 return result; 76 } 77 78 // Returns the number of all blocks kept in this structure. 79 uintx num_blocks() const { 80 uintx result = dictionary()->total_free_blocks(); 81 if (_small_blocks != NULL) { 82 result = result + _small_blocks->total_num_blocks(); 83 } 84 return result; 85 } 86 87 static size_t min_dictionary_size() { return TreeChunk<Metablock, FreeList<Metablock> >::min_size(); } 88 void print_on(outputStream* st) const; 89 }; 90 91 } // namespace metaspace 92 } // namespace internals 93 94 #endif /* SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP_ */