1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/metachunk.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,180 @@
1.4 +/*
1.5 + * Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "memory/allocation.hpp"
1.30 +#include "memory/metachunk.hpp"
1.31 +#include "utilities/copy.hpp"
1.32 +#include "utilities/debug.hpp"
1.33 +
1.34 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.35 +
1.36 +class VirtualSpaceNode;
1.37 +
1.38 +const size_t metadata_chunk_initialize = 0xf7f7f7f7;
1.39 +
1.40 +size_t Metachunk::object_alignment() {
1.41 + // Must align pointers and sizes to 8,
1.42 + // so that 64 bit types get correctly aligned.
1.43 + const size_t alignment = 8;
1.44 +
1.45 + // Make sure that the Klass alignment also agree.
1.46 + STATIC_ASSERT(alignment == (size_t)KlassAlignmentInBytes);
1.47 +
1.48 + return alignment;
1.49 +}
1.50 +
1.51 +size_t Metachunk::overhead() {
1.52 + return align_size_up(sizeof(Metachunk), object_alignment()) / BytesPerWord;
1.53 +}
1.54 +
1.55 +// Metachunk methods
1.56 +
1.57 +Metachunk::Metachunk(size_t word_size,
1.58 + VirtualSpaceNode* container)
1.59 + : Metabase<Metachunk>(word_size),
1.60 + _top(NULL),
1.61 + _container(container)
1.62 +{
1.63 + _top = initial_top();
1.64 +#ifdef ASSERT
1.65 + set_is_tagged_free(false);
1.66 + size_t data_word_size = pointer_delta(end(),
1.67 + _top,
1.68 + sizeof(MetaWord));
1.69 + Copy::fill_to_words((HeapWord*)_top,
1.70 + data_word_size,
1.71 + metadata_chunk_initialize);
1.72 +#endif
1.73 +}
1.74 +
1.75 +MetaWord* Metachunk::allocate(size_t word_size) {
1.76 + MetaWord* result = NULL;
1.77 + // If available, bump the pointer to allocate.
1.78 + if (free_word_size() >= word_size) {
1.79 + result = _top;
1.80 + _top = _top + word_size;
1.81 + }
1.82 + return result;
1.83 +}
1.84 +
1.85 +// _bottom points to the start of the chunk including the overhead.
1.86 +size_t Metachunk::used_word_size() const {
1.87 + return pointer_delta(_top, bottom(), sizeof(MetaWord));
1.88 +}
1.89 +
1.90 +size_t Metachunk::free_word_size() const {
1.91 + return pointer_delta(end(), _top, sizeof(MetaWord));
1.92 +}
1.93 +
1.94 +void Metachunk::print_on(outputStream* st) const {
1.95 + st->print_cr("Metachunk:"
1.96 + " bottom " PTR_FORMAT " top " PTR_FORMAT
1.97 + " end " PTR_FORMAT " size " SIZE_FORMAT,
1.98 + bottom(), _top, end(), word_size());
1.99 + if (Verbose) {
1.100 + st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT,
1.101 + used_word_size(), free_word_size());
1.102 + }
1.103 +}
1.104 +
1.105 +#ifndef PRODUCT
1.106 +void Metachunk::mangle() {
1.107 + // Mangle the payload of the chunk and not the links that
1.108 + // maintain list of chunks.
1.109 + HeapWord* start = (HeapWord*)(bottom() + overhead());
1.110 + size_t size = word_size() - overhead();
1.111 + Copy::fill_to_words(start, size, metadata_chunk_initialize);
1.112 +}
1.113 +#endif // PRODUCT
1.114 +
1.115 +void Metachunk::verify() {
1.116 +#ifdef ASSERT
1.117 + // Cannot walk through the blocks unless the blocks have
1.118 + // headers with sizes.
1.119 + assert(bottom() <= _top &&
1.120 + _top <= (MetaWord*)end(),
1.121 + "Chunk has been smashed");
1.122 +#endif
1.123 + return;
1.124 +}
1.125 +
1.126 +/////////////// Unit tests ///////////////
1.127 +
1.128 +#ifndef PRODUCT
1.129 +
1.130 +class TestMetachunk {
1.131 + public:
1.132 + static void test() {
1.133 + size_t size = 2 * 1024 * 1024;
1.134 + void* memory = malloc(size);
1.135 + assert(memory != NULL, "Failed to malloc 2MB");
1.136 +
1.137 + Metachunk* metachunk = ::new (memory) Metachunk(size / BytesPerWord, NULL);
1.138 +
1.139 + assert(metachunk->bottom() == (MetaWord*)metachunk, "assert");
1.140 + assert(metachunk->end() == (uintptr_t*)metachunk + metachunk->size(), "assert");
1.141 +
1.142 + // Check sizes
1.143 + assert(metachunk->size() == metachunk->word_size(), "assert");
1.144 + assert(metachunk->word_size() == pointer_delta(metachunk->end(), metachunk->bottom(),
1.145 + sizeof(MetaWord*)), "assert");
1.146 +
1.147 + // Check usage
1.148 + assert(metachunk->used_word_size() == metachunk->overhead(), "assert");
1.149 + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
1.150 + assert(metachunk->top() == metachunk->initial_top(), "assert");
1.151 + assert(metachunk->is_empty(), "assert");
1.152 +
1.153 + // Allocate
1.154 + size_t alloc_size = 64; // Words
1.155 + assert(is_size_aligned(alloc_size, Metachunk::object_alignment()), "assert");
1.156 +
1.157 + MetaWord* mem = metachunk->allocate(alloc_size);
1.158 +
1.159 + // Check post alloc
1.160 + assert(mem == metachunk->initial_top(), "assert");
1.161 + assert(mem + alloc_size == metachunk->top(), "assert");
1.162 + assert(metachunk->used_word_size() == metachunk->overhead() + alloc_size, "assert");
1.163 + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
1.164 + assert(!metachunk->is_empty(), "assert");
1.165 +
1.166 + // Clear chunk
1.167 + metachunk->reset_empty();
1.168 +
1.169 + // Check post clear
1.170 + assert(metachunk->used_word_size() == metachunk->overhead(), "assert");
1.171 + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
1.172 + assert(metachunk->top() == metachunk->initial_top(), "assert");
1.173 + assert(metachunk->is_empty(), "assert");
1.174 +
1.175 + free(memory);
1.176 + }
1.177 +};
1.178 +
1.179 +void TestMetachunk_test() {
1.180 + TestMetachunk::test();
1.181 +}
1.182 +
1.183 +#endif
