haiku/src/system/libroot/posix/malloc/superblock.cpp
Axel Dörfler 5af32e7526 Renamed src/kernel to src/system.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@12359 a95241bf-73f2-0310-859d-f6bbb57e9c96
2005-04-13 13:06:35 +00:00

130 lines
4.1 KiB
C++

///-*-C++-*-//////////////////////////////////////////////////////////////////
//
// The Hoard Multiprocessor Memory Allocator
// Contact author: Emery Berger, http://www.cs.utexas.edu/users/emery
//
// Copyright (c) 1998-2000, The University of Texas at Austin.
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as
// published by the Free Software Foundation, http://www.fsf.org.
//
// This library 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
// Library General Public License for more details.
//
//////////////////////////////////////////////////////////////////////////////
/*
superblock.cpp
------------------------------------------------------------------------
The superblock class controls a number of blocks (which are
allocatable units of memory).
------------------------------------------------------------------------
Emery Berger | <http://www.cs.utexas.edu/users/emery>
Department of Computer Sciences | <http://www.cs.utexas.edu>
University of Texas at Austin | <http://www.utexas.edu>
========================================================================
*/
#include <string.h>
#include "arch-specific.h"
#include "config.h"
#include "heap.h"
#include "processheap.h"
#include "superblock.h"
using namespace BPrivate;
superblock::superblock(int numBlocks, // The number of blocks in the sb.
int szclass, // The size class of the blocks.
hoardHeap * o) // The heap that "owns" this sb.
:
#if HEAP_DEBUG
_magic(SUPERBLOCK_MAGIC),
#endif
_sizeClass(szclass),
_numBlocks(numBlocks),
_numAvailable(0),
_fullness(0), _freeList(NULL), _owner(o), _next(NULL), _prev(NULL)
{
assert(_numBlocks >= 1);
// Determine the size of each block.
const int blksize = hoardHeap::align(sizeof(block)
+ hoardHeap::sizeFromClass(_sizeClass));
// Make sure this size is in fact aligned.
assert((blksize & hoardHeap::ALIGNMENT_MASK) == 0);
// Set the first block to just past this superblock header.
block *b = (block *) hoardHeap::align((unsigned long)(this + 1));
// Initialize all the blocks,
// and insert the block pointers into the linked list.
for (int i = 0; i < _numBlocks; i++) {
// Make sure the block is on a double-word boundary.
assert(((unsigned int)b & hoardHeap::ALIGNMENT_MASK) == 0);
new(b) block(this);
assert(b->getSuperblock() == this);
b->setNext(_freeList);
_freeList = b;
b = (block *)((char *)b + blksize);
}
_numAvailable = _numBlocks;
computeFullness();
assert((unsigned long)b <= hoardHeap::align(sizeof(superblock) + blksize * _numBlocks)
+ (unsigned long)this);
hoardLockInit(_upLock, "hoard superblock");
}
superblock *
superblock::makeSuperblock(int sizeclass, processHeap *pHeap)
{
// We need to get more memory.
char *buf;
int numBlocks = hoardHeap::numBlocks(sizeclass);
// Compute how much memory we need.
unsigned long moreMemory;
if (numBlocks > 1) {
moreMemory = hoardHeap::SUPERBLOCK_SIZE;
assert(moreMemory >= hoardHeap::align(sizeof(superblock)
+ (hoardHeap::align(sizeof(block)
+ hoardHeap::sizeFromClass(sizeclass))) * numBlocks));
// Get some memory from the process heap.
buf = (char *)pHeap->getSuperblockBuffer();
} else {
// One object.
assert(numBlocks == 1);
size_t blksize = hoardHeap::align(sizeof(block)
+ hoardHeap::sizeFromClass(sizeclass));
moreMemory = hoardHeap::align(sizeof(superblock) + blksize);
// Get space from the system.
buf = (char *)hoardSbrk(moreMemory);
}
// Make sure that we actually got the memory.
if (buf == NULL)
return 0;
buf = (char *)hoardHeap::align((unsigned long)buf);
// Make sure this buffer is double-word aligned.
assert(buf == (char *)hoardHeap::align((unsigned long)buf));
assert((((unsigned long)buf) & hoardHeap::ALIGNMENT_MASK) == 0);
// Instantiate the new superblock in the buffer.
return new(buf) superblock(numBlocks, sizeclass, NULL);
}