1 /* 2 * Copyright (c) 2012, 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 "memory/allocation.hpp" 27 #include "memory/metachunk.hpp" 28 #include "utilities/copy.hpp" 29 #include "utilities/debug.hpp" 30 31 class VirtualSpaceNode; 32 33 const size_t metadata_chunk_initialize = 0xf7f7f7f7; 34 35 size_t Metachunk::object_alignment() { 36 return ARENA_AMALLOC_ALIGNMENT; 37 } 38 39 size_t Metachunk::overhead() { 40 return align_size_up(sizeof(Metachunk), object_alignment()) / BytesPerWord; 41 } 42 43 // Metachunk methods 44 45 Metachunk::Metachunk(size_t word_size, 46 VirtualSpaceNode* container) 47 : Metamem<Metachunk>(word_size), 48 _top(NULL), 49 _container(container) 50 { 51 _top = initial_top(); 52 #ifdef ASSERT 53 set_is_marked_free(false); 54 size_t data_word_size = pointer_delta(end(), 55 _top, 56 sizeof(MetaWord)); 57 Copy::fill_to_words((HeapWord*)_top, 58 data_word_size, 59 metadata_chunk_initialize); 60 #endif 61 } 62 63 MetaWord* Metachunk::allocate(size_t word_size) { 64 MetaWord* result = NULL; 65 // If available, bump the pointer to allocate. 66 if (free_word_size() >= word_size) { 67 result = _top; 68 _top = _top + word_size; 69 } 70 return result; 71 } 72 73 // _bottom points to the start of the chunk including the overhead. 74 size_t Metachunk::used_word_size() const { 75 return pointer_delta(_top, bottom(), sizeof(MetaWord)); 76 } 77 78 size_t Metachunk::free_word_size() const { 79 return pointer_delta(end(), _top, sizeof(MetaWord)); 80 } 81 82 void Metachunk::print_on(outputStream* st) const { 83 st->print_cr("Metachunk:" 84 " bottom " PTR_FORMAT " top " PTR_FORMAT 85 " end " PTR_FORMAT " size " SIZE_FORMAT, 86 bottom(), _top, end(), word_size()); 87 if (Verbose) { 88 st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT, 89 used_word_size(), free_word_size()); 90 } 91 } 92 93 #ifndef PRODUCT 94 void Metachunk::mangle() { 95 // Mangle the payload of the chunk and not the links that 96 // maintain list of chunks. 97 HeapWord* start = (HeapWord*)(bottom() + overhead()); 98 size_t size = word_size() - overhead(); 99 Copy::fill_to_words(start, size, metadata_chunk_initialize); 100 } 101 #endif // PRODUCT 102 103 void Metachunk::verify() { 104 #ifdef ASSERT 105 // Cannot walk through the blocks unless the blocks have 106 // headers with sizes. 107 assert(bottom() <= _top && 108 _top <= (MetaWord*)end(), 109 "Chunk has been smashed"); 110 #endif 111 return; 112 } 113 114 /////////////// Unit tests /////////////// 115 116 #ifndef PRODUCT 117 118 class TestMetachunk { 119 public: 120 static void test() { 121 size_t size = 2 * 1024 * 1024; 122 void* memory = malloc(size); 123 assert(memory != NULL, "Failed to malloc 2MB"); 124 125 Metachunk* metachunk = new (memory) Metachunk(size / BytesPerWord, NULL); 126 127 assert(metachunk->bottom() == (MetaWord*)metachunk, "assert"); 128 assert(metachunk->end() == (uintptr_t*)metachunk + metachunk->size(), "assert"); 129 130 // Check sizes 131 assert(metachunk->size() == metachunk->word_size(), "assert"); 132 assert(metachunk->word_size() == pointer_delta(metachunk->end(), metachunk->bottom(), 133 sizeof(MetaWord*)), "assert"); 134 135 // Check usage 136 assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); 137 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 138 assert(metachunk->top() == metachunk->initial_top(), "assert"); 139 assert(metachunk->is_empty(), "assert"); 140 141 // Allocate 142 size_t alloc_size = 64; // Words 143 assert(is_size_aligned(alloc_size, Metachunk::object_alignment()), "assert"); 144 145 MetaWord* mem = metachunk->allocate(alloc_size); 146 147 // Check post alloc 148 assert(mem == metachunk->initial_top(), "assert"); 149 assert(mem + alloc_size == metachunk->top(), "assert"); 150 assert(metachunk->used_word_size() == metachunk->overhead() + alloc_size, "assert"); 151 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 152 assert(!metachunk->is_empty(), "assert"); 153 154 // Clear chunk 155 metachunk->reset_empty(); 156 157 // Check post clear 158 assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); 159 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 160 assert(metachunk->top() == metachunk->initial_top(), "assert"); 161 assert(metachunk->is_empty(), "assert"); 162 163 free(memory); 164 } 165 }; 166 167 void TestMetachunk_test() { 168 TestMetachunk::test(); 169 } 170 171 #endif