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// $Header$
//
// \file private_allocator.cc
// This file contains the implementation of our own STL allocator, used with g++-4.x.
//
// Copyright (C) 2005, by
//
// Carlo Wood, Run on IRC <carlo@alinoe.com>
// RSA-1024 0x624ACAD5 1997-01-26 Sign & Encrypt
// Fingerprint16 = 32 EC A7 B6 AC DB 65 A6 F6 F6 55 DD 1C DC FF 61
//
// This file may be distributed under the terms of the Q Public License
// version 1.0 as appearing in the file LICENSE.QPL included in the
// packaging of this file.
//
#include "sys.h"
#include <libcwd/config.h>
#if CWDEBUG_ALLOC && __GNUC__ == 4
#include <libcwd/private_allocator.h>
#include <libcwd/private_set_alloc_checking.h>
#include "zone.h"
namespace libcwd {
namespace _private_ {
// Maximum overhead needed for non-internal allocations.
#if CWDEBUG_MAGIC
static size_t const malloc_overhead_c = sizeof(prezone) + sizeof(size_t) - 1 + sizeof(postzone) + CW_MALLOC_OVERHEAD;
#else
static size_t const malloc_overhead_c = CW_MALLOC_OVERHEAD;
#endif
// The minimum size we allocate: two or three page sizes minus the (maximum) malloc
// overhead (modulo the page size). Since this is rather large, we assume
// the same for internal allocations (which is only not true when configuring
// libcwd with --disable-magic).
static size_t const page_size_c = 4096;
#if defined(LIBCWD_REDZONE_BLOCKS) && LIBCWD_REDZONE_BLOCKS > 0
static size_t const block_size_c = 3 * page_size_c - (malloc_overhead_c % page_size_c);
#else
static size_t const block_size_c = 2 * page_size_c - malloc_overhead_c;
#endif
char* FreeList::allocate(int power, size_t size)
{
BlockList& list(M_list_notfull[power - minimum_size_exp]); // The linked list with Block's that aren't full yet.
Node const* const end = list.end(); // The 'end' node of the list.
BlockNode* block = list.begin(); // Make block point to begin.
if (block == end) // No non-empty blocks left?
{
// Allocate a new BlockNode.
block = reinterpret_cast<BlockNode*>(::operator new(block_size_c));
// Partition BlockNode.
Node* first_chunk = block->M_data; // First chunk.
block->M_chunks.M_next = first_chunk; // Make root point to the first chunk.
first_chunk->M_prev = &block->M_chunks; // Make first chunk point back to the root.
int const offset_of_M_data = (char*)first_chunk - (char*)block;
int const number_of_chunks = (block_size_c - offset_of_M_data) / size;
Node* chunk = first_chunk;
for (int i = 1; i < number_of_chunks; ++i)
{
Node* prev_chunk = chunk;
chunk = reinterpret_cast<Node*>((char*)chunk + size); // Next chunk.
chunk->M_prev = prev_chunk;
prev_chunk->M_next = chunk;
}
// Link root and last chunk.
block->M_chunks.M_prev = chunk;
chunk->M_next = &block->M_chunks;
// The number of allocated chunks.
block->M_chunks.M_used_count = 0;
// Insert block at the front of the chain.
list.insert(block);
++M_count[power - minimum_size_exp];
}
ChunkNode* chunk = block->M_chunks.begin(); // Get the first chunk of this (free) list.
chunk->unlink(); // Unlink the chunk from the free list.
++block->M_chunks.M_used_count; // Number of chunks in use in this block.
if (block->M_chunks.empty())
{
// There are no more (free) chunks in this block, need to move
// it from M_list_notfull to M_list_full.
block->unlink(); // Remove it from M_list_notfull.
M_list_full[power - minimum_size_exp].insert(block); // Add it to M_list_full.
}
*reinterpret_cast<BlockNode**>(chunk) = block;
return (char*)chunk + sizeof(BlockNode*);
}
void FreeList::deallocate(char* ptr, int power, size_t /*size*/)
{
ptr -= sizeof(BlockNode*);
BlockNode* block = *reinterpret_cast<BlockNode**>(ptr);
Node* chunk = reinterpret_cast<Node*>(ptr);
if (block->M_chunks.empty())
{
// Move the block back to M_list_notfull.
block->unlink(); // Remove it from M_list_full.
M_list_notfull[power - minimum_size_exp].insert_back(block); // Add it to M_list_notfull.
}
block->M_chunks.insert(chunk);
if (--block->M_chunks.M_used_count == 0 && M_count[power - minimum_size_exp] > M_keep[power - minimum_size_exp])
{
// ChunkList of block empty (and not the last block): remove it.
block->unlink();
::operator delete(block);
--M_count[power - minimum_size_exp];
}
}
void BlockList::initialize(unsigned int* count_ptr, unsigned short internal)
{
M_next = M_prev = this;
M_count_ptr = count_ptr;
M_internal = internal;
}
void BlockList::uninitialize(void)
{
if (!M_next) // Never initialized?
return;
#if CWDEBUG_DEBUG
consistency_check();
#endif
// No need for locking here-- this is only called when there is just one thread left.
BlockList& list(*this);
BlockNode* block = list.begin(); // There can be at most M_keep empty blocks.
Node const* const end = list.end(); // The 'end' node of the list.
// Search for first non-empty BlockNode.
while (block != end && block->M_chunks.M_used_count == 0)
{
block->unlink();
BlockNode* next = block->next();
LIBCWD_TSD_DECLARATION;
if (M_internal)
set_alloc_checking_off(LIBCWD_TSD);
::operator delete(block);
if (M_internal)
set_alloc_checking_on(LIBCWD_TSD);
--(*M_count_ptr);
block = next;
}
}
void FreeList::uninitialize(void)
{
if (!M_initialized)
return;
#if CWDEBUG_DEBUG
consistency_check();
#endif
// Delete all empty blocks from now on.
for (int i = 0; i < bucket_sizes; ++i)
M_keep[i] = 0;
}
#if LIBCWD_THREAD_SAFE
pthread_mutex_t FreeList::S_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
void FreeList::initialize(LIBCWD_TSD_PARAM)
{
bool initialized;
#if LIBCWD_THREAD_SAFE
pthread_mutex_lock(&S_mutex);
#endif
initialized = M_initialized;
M_initialized = true;
#if LIBCWD_THREAD_SAFE
pthread_mutex_unlock(&S_mutex);
#endif
if (initialized)
return;
#if LIBCWD_THREAD_SAFE
pthread_mutexattr_t mutex_attr;
pthread_mutexattr_init(&mutex_attr);
#if CWDEBUG_DEBUGT
pthread_mutexattr_settype(&mutex_attr, PTHREAD_MUTEX_ERRORCHECK);
#else
pthread_mutexattr_settype(&mutex_attr, PTHREAD_MUTEX_NORMAL);
#endif
pthread_mutex_init(&M_mutex, &mutex_attr);
pthread_mutexattr_destroy(&mutex_attr);
#endif
for (int i = 0; i < bucket_sizes; ++i)
{
M_count[i] = 0;
M_keep[i] = 1;
M_list_notfull[i].initialize(&M_count[i], (__libcwd_tsd.internal > 0) ? 1 : 0);
M_list_full[i].initialize(&M_count[i], (__libcwd_tsd.internal > 0) ? 1 : 0);
}
}
#if CWDEBUG_DEBUG
void FreeList::consistency_check(void)
{
assert(M_initialized);
// M_mutex is either already locked when we get here, or there is just one thread.
for (int i = 0; i < bucket_sizes; ++i)
{
assert(M_keep[i] == 1);
assert(M_list_notfull[i].M_count_ptr == &M_count[i]);
assert(M_list_full[i].M_count_ptr == &M_count[i]);
M_list_notfull[i].consistency_check();
M_list_full[i].consistency_check();
unsigned int count = 0;
for (Node* iter = M_list_notfull[i].begin(); iter != M_list_notfull[i].end(); iter = iter->M_next)
++count;
for (Node* iter = M_list_full[i].begin(); iter != M_list_full[i].end(); iter = iter->M_next)
++count;
assert(count == M_count[i]);
}
}
void BlockList::consistency_check(void)
{
assert(begin() == M_next);
assert(end() == this);
Node* prev_node = this;
Node* node = begin();
int count = 0;
do
{
assert(node->M_prev == prev_node);
prev_node = node;
node = node->M_next;
++count;
}
while (node != M_next && count != 123456);
assert(count != 123456);
}
#endif
} // namespace _private_
} // namespace libcwd
#endif // CWDEBUG_ALLOC && __GNUC__ == 4
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