Mercurial > hg > graal-compiler
view src/share/vm/memory/metachunk.cpp @ 9484:2b663d5893d3
Allow rounding errors in probabilities
author | Christian Wimmer <christian.wimmer@oracle.com> |
---|---|
date | Wed, 01 May 2013 13:33:07 -0700 |
parents | e51c9860cf66 |
children | c23dbf0e8ab7 |
line wrap: on
line source
/* * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "memory/allocation.hpp" #include "memory/metachunk.hpp" #include "utilities/copy.hpp" #include "utilities/debug.hpp" // // Future modification // // The Metachunk can conceivable be replaced by the Chunk in // allocation.hpp. Note that the latter Chunk is the space for // allocation (allocations from the chunk are out of the space in // the Chunk after the header for the Chunk) where as Metachunks // point to space in a VirtualSpace. To replace Metachunks with // Chunks, change Chunks so that they can be allocated out of a VirtualSpace. const size_t metadata_chunk_initialize = 0xf7f7f7f7; size_t Metachunk::_overhead = Chunk::aligned_overhead_size(sizeof(Metachunk)) / BytesPerWord; // Metachunk methods Metachunk* Metachunk::initialize(MetaWord* ptr, size_t word_size) { // Set bottom, top, and end. Allow space for the Metachunk itself Metachunk* chunk = (Metachunk*) ptr; MetaWord* chunk_bottom = ptr + _overhead; chunk->set_bottom(ptr); chunk->set_top(chunk_bottom); MetaWord* chunk_end = ptr + word_size; assert(chunk_end > chunk_bottom, "Chunk must be too small"); chunk->set_end(chunk_end); chunk->set_next(NULL); chunk->set_prev(NULL); chunk->set_word_size(word_size); #ifdef ASSERT size_t data_word_size = pointer_delta(chunk_end, chunk_bottom, sizeof(MetaWord)); Copy::fill_to_words((HeapWord*) chunk_bottom, data_word_size, metadata_chunk_initialize); #endif return chunk; } MetaWord* Metachunk::allocate(size_t word_size) { MetaWord* result = NULL; // If available, bump the pointer to allocate. if (free_word_size() >= word_size) { result = _top; _top = _top + word_size; } return result; } // _bottom points to the start of the chunk including the overhead. size_t Metachunk::used_word_size() const { return pointer_delta(_top, _bottom, sizeof(MetaWord)); } size_t Metachunk::free_word_size() const { return pointer_delta(_end, _top, sizeof(MetaWord)); } size_t Metachunk::capacity_word_size() const { return pointer_delta(_end, _bottom, sizeof(MetaWord)); } void Metachunk::print_on(outputStream* st) const { st->print_cr("Metachunk:" " bottom " PTR_FORMAT " top " PTR_FORMAT " end " PTR_FORMAT " size " SIZE_FORMAT, bottom(), top(), end(), word_size()); if (Verbose) { st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT, used_word_size(), free_word_size()); } } #ifndef PRODUCT void Metachunk::mangle() { // Mangle the payload of the chunk and not the links that // maintain list of chunks. HeapWord* start = (HeapWord*)(bottom() + overhead()); size_t word_size = capacity_word_size() - overhead(); Copy::fill_to_words(start, word_size, metadata_chunk_initialize); } #endif // PRODUCT void Metachunk::verify() { #ifdef ASSERT // Cannot walk through the blocks unless the blocks have // headers with sizes. assert(_bottom <= _top && _top <= _end, "Chunk has been smashed"); #endif return; }