Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2012, 2013, 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/metablock.hpp"

 #include "utilities/copy.hpp"

 #include "utilities/debug.hpp"

 // Blocks of space for metadata are allocated out of Metachunks.

 //

 // Metachunk are allocated out of MetadataVirtualspaces and once

 // allocated there is no explicit link between a Metachunk and

 // the MetadataVirtualspaces from which it was allocated.

 //

 // Each SpaceManager maintains a

 // list of the chunks it is using and the current chunk.  The current

 // chunk is the chunk from which allocations are done.  Space freed in

 // a chunk is placed on the free list of blocks (BlockFreelist) and

 // reused from there.

 //

 // 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.

 size_t Metablock::_min_block_byte_size = sizeof(Metablock);

 #ifdef ASSERT

 size_t Metablock::_overhead =

   Chunk::aligned_overhead_size(sizeof(Metablock)) / BytesPerWord;

 #else

 size_t Metablock::_overhead = 0;

 #endif

 // New blocks returned by the Metaspace are zero initialized.

 // We should fix the constructors to not assume this instead.

 Metablock* Metablock::initialize(MetaWord* p, size_t word_size) {

   if (p == NULL) {

     return NULL;

   }

   Metablock* result = (Metablock*) p;

   // Clear the memory

   Copy::fill_to_aligned_words((HeapWord*)result, word_size);

 #ifdef ASSERT

   result->set_word_size(word_size);

 #endif

   return result;

 }