1 /* 2 * Copyright (c) 2012, 2014, 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 // Must align pointers and sizes to 8, 37 // so that 64 bit types get correctly aligned. 38 const size_t alignment = 8; 39 40 // Make sure that the Klass alignment also agree. 41 STATIC_ASSERT(alignment == (size_t)KlassAlignmentInBytes); 42 43 return alignment; 44 } 45 46 size_t Metachunk::overhead() { 47 return align_size_up(sizeof(Metachunk), object_alignment()) / BytesPerWord; 48 } 49 50 // Metachunk methods 51 52 Metachunk::Metachunk(size_t word_size, 53 VirtualSpaceNode* container) 54 : Metabase<Metachunk>(word_size), 55 _top(NULL), 56 _container(container) 57 { 58 _top = initial_top(); 59 #ifdef ASSERT 60 set_is_tagged_free(false); 61 size_t data_word_size = pointer_delta(end(), 62 _top, 63 sizeof(MetaWord)); 64 Copy::fill_to_words((HeapWord*)_top, 65 data_word_size, 66 metadata_chunk_initialize); 67 #endif 68 } 69 70 MetaWord* Metachunk::allocate(size_t word_size) { 71 MetaWord* result = NULL; 72 // If available, bump the pointer to allocate. 73 if (free_word_size() >= word_size) { 74 result = _top; 75 _top = _top + word_size; 76 } 77 return result; 78 } 79 80 // _bottom points to the start of the chunk including the overhead. 81 size_t Metachunk::used_word_size() const { 82 return pointer_delta(_top, bottom(), sizeof(MetaWord)); 83 } 84 85 size_t Metachunk::free_word_size() const { 86 return pointer_delta(end(), _top, sizeof(MetaWord)); 87 } 88 89 void Metachunk::print_on(outputStream* st) const { 90 st->print_cr("Metachunk:" 91 " bottom " PTR_FORMAT " top " PTR_FORMAT 92 " end " PTR_FORMAT " size " SIZE_FORMAT, 93 p2i(bottom()), p2i(_top), p2i(end()), word_size()); 94 if (Verbose) { 95 st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT, 96 used_word_size(), free_word_size()); 97 } 98 } 99 100 #ifndef PRODUCT 101 void Metachunk::mangle() { 102 // Mangle the payload of the chunk and not the links that 103 // maintain list of chunks. 104 HeapWord* start = (HeapWord*)(bottom() + overhead()); 105 size_t size = word_size() - overhead(); 106 Copy::fill_to_words(start, size, metadata_chunk_initialize); 107 } 108 #endif // PRODUCT 109 110 void Metachunk::verify() { 111 #ifdef ASSERT 112 // Cannot walk through the blocks unless the blocks have 113 // headers with sizes. 114 assert(bottom() <= _top && 115 _top <= (MetaWord*)end(), 116 "Chunk has been smashed"); 117 #endif 118 return; 119 } 120 121 /////////////// Unit tests /////////////// 122 123 #ifndef PRODUCT 124 125 class TestMetachunk { 126 public: 127 static void test() { 128 size_t size = 2 * 1024 * 1024; 129 void* memory = malloc(size); 130 assert(memory != NULL, "Failed to malloc 2MB"); 131 132 Metachunk* metachunk = ::new (memory) Metachunk(size / BytesPerWord, NULL); 133 134 assert(metachunk->bottom() == (MetaWord*)metachunk, "assert"); 135 assert(metachunk->end() == (uintptr_t*)metachunk + metachunk->size(), "assert"); 136 137 // Check sizes 138 assert(metachunk->size() == metachunk->word_size(), "assert"); 139 assert(metachunk->word_size() == pointer_delta(metachunk->end(), metachunk->bottom(), 140 sizeof(MetaWord*)), "assert"); 141 142 // Check usage 143 assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); 144 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 145 assert(metachunk->top() == metachunk->initial_top(), "assert"); 146 assert(metachunk->is_empty(), "assert"); 147 148 // Allocate 149 size_t alloc_size = 64; // Words 150 assert(is_size_aligned(alloc_size, Metachunk::object_alignment()), "assert"); 151 152 MetaWord* mem = metachunk->allocate(alloc_size); 153 154 // Check post alloc 155 assert(mem == metachunk->initial_top(), "assert"); 156 assert(mem + alloc_size == metachunk->top(), "assert"); 157 assert(metachunk->used_word_size() == metachunk->overhead() + alloc_size, "assert"); 158 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 159 assert(!metachunk->is_empty(), "assert"); 160 161 // Clear chunk 162 metachunk->reset_empty(); 163 164 // Check post clear 165 assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); 166 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); 167 assert(metachunk->top() == metachunk->initial_top(), "assert"); 168 assert(metachunk->is_empty(), "assert"); 169 170 free(memory); 171 } 172 }; 173 174 void TestMetachunk_test() { 175 TestMetachunk::test(); 176 } 177 178 #endif