memory pools
[D-Bus secret internal implementation details]

DBusMemPool object. More...

Typedefs
typedef DBusMemPool	DBusMemPool
	Opaque object representing a memory pool.
Functions
DBusMemPool *	_dbus_mem_pool_new (int element_size, dbus_bool_t zero_elements)
	Creates a new memory pool, or returns NULL on failure.
void	_dbus_mem_pool_free (DBusMemPool *pool)
	Frees a memory pool (and all elements allocated from it).
void *	_dbus_mem_pool_alloc (DBusMemPool *pool)
	Allocates an object from the memory pool.
dbus_bool_t	_dbus_mem_pool_dealloc (DBusMemPool *pool, void *element)
	Deallocates an object previously created with _dbus_mem_pool_alloc().

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Detailed Description

DBusMemPool object.

Types and functions related to DBusMemPool. A memory pool is used to decrease memory fragmentation/overhead and increase speed for blocks of small uniformly-sized objects. The main point is to avoid the overhead of a malloc block for each small object, speed is secondary.

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Typedef Documentation

DBusMemPool

Opaque object representing a memory pool.

Memory pools allow avoiding per-malloc-block memory overhead when allocating a lot of small objects that are all the same size. They are slightly faster than calling malloc() also.

Definition at line 33 of file dbus-mempool.h.

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Function Documentation

void* _dbus_mem_pool_alloc

(

DBusMemPool *

pool

)

Allocates an object from the memory pool.

The object must be freed with _dbus_mem_pool_dealloc().

Parameters:

pool

the memory pool

Returns:

the allocated object or NULL if no memory.

Definition at line 208 of file dbus-mempool.c.

References _dbus_assert, _DBUS_INT_MAX, allocated_elements, block_size, blocks, dbus_malloc(), dbus_malloc0(), ELEMENT_PADDING, element_size, DBusMemBlock::elements, free_elements, DBusMemBlock::next, DBusFreedElement::next, NULL, DBusMemBlock::used_so_far, and zero_elements.

dbus_bool_t _dbus_mem_pool_dealloc	(	DBusMemPool *	pool,
		void *	element
	)

Deallocates an object previously created with _dbus_mem_pool_alloc().

The previous object must have come from this same pool.

Parameters:

	pool	the memory pool
	element	the element earlier allocated.

Returns:

TRUE if there are no remaining allocated elements

Definition at line 336 of file dbus-mempool.c.

References _dbus_assert, _dbus_assert_not_reached, allocated_elements, blocks, dbus_free(), DBusMemBlock::elements, FALSE, free_elements, DBusMemBlock::next, DBusFreedElement::next, and NULL.

Referenced by _dbus_hash_table_free_preallocated_entry().

void _dbus_mem_pool_free

(

DBusMemPool *

pool

)

Frees a memory pool (and all elements allocated from it).

Parameters:

pool

the memory pool.

Definition at line 183 of file dbus-mempool.c.

References blocks, dbus_free(), DBusMemBlock::next, and NULL.

Referenced by _dbus_hash_table_unref().

DBusMemPool* _dbus_mem_pool_new	(	int	element_size,
		dbus_bool_t	zero_elements
	)

Creates a new memory pool, or returns NULL on failure.

Objects in the pool must be at least sizeof(void*) bytes each, due to the way memory pools work. To avoid creating 64 bit problems, this means at least 8 bytes on all platforms, unless you are 4 bytes on 32-bit and 8 bytes on 64-bit.

Parameters:

	element_size	size of an element allocated from the pool.
	zero_elements	whether to zero-initialize elements

Returns:

the new pool or NULL

Definition at line 136 of file dbus-mempool.c.

References _dbus_assert, allocated_elements, block_size, dbus_new0, element_size, FALSE, NULL, and zero_elements.

Referenced by _dbus_hash_table_new().

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