Virtual memory support
[Portability layer]

Modules
	Memory protection flags
	Memory page size directives
	These defines can be used instead of explicit calls to port_vmem_page_sizes().
Typedefs
typedef port_vmem_t	port_vmem_t
	Virtual memory block descriptor.
Functions
apr_status_t	port_vmem_reserve (port_vmem_t **block, void **address, size_t amount, unsigned int protectionMode, size_t pageSize, apr_pool_t *pool)
	Reserves a continuous memory region in the virtual address space of the calling process.
apr_status_t	port_vmem_commit (void **address, size_t amount, port_vmem_t *block)
	Commits (a part of) the previously reserved memory region.
apr_status_t	port_vmem_decommit (void *address, size_t amount, port_vmem_t *block)
	Decommits the specified region of committed memory.
apr_status_t	port_vmem_release (port_vmem_t *block)
	Releases previously reserved virtual memory region as a whole.
size_t *	port_vmem_page_sizes ()
	Returns a zero-terminated array of supported memory page sizes.
size_t	port_vmem_used_size ()
	Returns the amount of currently used memory in bytes or 0 if this value could not be calculated.
size_t	port_vmem_committed_size ()
	Returns the amount of committed memory in bytes or 0 if this value could not be calculated.
size_t	port_vmem_reserved_size ()
	Returns the amount of reserved memory in bytes or 0 if this value could not be calculated.
size_t	port_vmem_max_size ()
	Returns the maximum amount of memory which could be reserved in bytes or 0 if this value could not be calculated.
apr_status_t	port_vmem_allocate (void **addr, size_t size, unsigned int mode)
	Allocate memory with default page size.
apr_status_t	port_vmem_free (void *addr, size_t size)
	Releases previously reserved virtual memory region as a whole.

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Typedef Documentation

typedef struct port_vmem_t port_vmem_t

Virtual memory block descriptor.

This is an incomplete type, the run-time instance should be obtained via port_vmem_reserve() call

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Function Documentation

apr_status_t port_vmem_reserve	(	port_vmem_t **	block,
		void **	address,
		size_t	amount,
		unsigned int	protectionMode,
		size_t	pageSize,
		apr_pool_t *	pool
	)

Reserves a continuous memory region in the virtual address space of the calling process.

Parameters:

[out]	block	- descriptor for the reserved memory, required for further operations with the memory
[in,out]	address	- desired starting address of the region to allocate. If NULL, the system determines the appropriate location.On success, the actual allocated address is returned
	amount	- the size of the region in bytes. For large pages, the size must be multiply of page size
	protectionMode	- the bit mask of PORT_VMEM_MODE_* flags
	pageSize	- the desired size of the memory page; should contain PORT_VMEM_PAGESIZE_DEFAULT, PORT_VMEM_PAGESIZE_LARGE or the actual size in bytes
	pool	- the auxiliary pool to allocate the descriptor data, etc

Returns:

APR_SUCCESS if OK; otherwise, an error code.

See also:

port_vmem_page_sizes()

apr_status_t port_vmem_commit	(	void **	address,
		size_t	amount,
		port_vmem_t *	block
	)

Commits (a part of) the previously reserved memory region.

The allocated memory is initialized to zero.

Parameters:

[in,out]	address	- the starting address of the region to commit; the returned value may differ due to page alignment
	amount	- the size of the region in bytes
	block	- the descriptor to the reserved virtual memory

Returns:

APR_SUCCESS if OK; otherwise, an error code.

apr_status_t port_vmem_decommit	(	void *	address,
		size_t	amount,
		port_vmem_t *	block
	)

Decommits the specified region of committed memory.

It is safe to decommit a reserved (but not committed) region.

Parameters:

	address	- the starting address of the region to decommit
	amount	- the size of the region in bytes
	block	- the memory region descriptor

Returns:

APR_SUCCESS if OK; otherwise, an error code.

apr_status_t port_vmem_release

(

port_vmem_t *

block

)

Releases previously reserved virtual memory region as a whole.

If the region was committed, the function first decommits it.

Parameters:

block

- the memory region descriptor

Returns:

APR_SUCCESS if OK; otherwise, an error code.

size_t* port_vmem_page_sizes

(

)

Returns a zero-terminated array of supported memory page sizes.

The first element refers to the system default size and is guaranteed to be non-zero. Subsequent elements (if any) provide large page sizes.

size_t port_vmem_used_size

(

)

Returns the amount of currently used memory in bytes or 0 if this value could not be calculated.

size_t port_vmem_committed_size

(

)

Returns the amount of committed memory in bytes or 0 if this value could not be calculated.

size_t port_vmem_reserved_size

(

)

Returns the amount of reserved memory in bytes or 0 if this value could not be calculated.

size_t port_vmem_max_size

(

)

Returns the maximum amount of memory which could be reserved in bytes or 0 if this value could not be calculated.

apr_status_t port_vmem_allocate	(	void **	addr,
		size_t	size,
		unsigned int	mode
	)

Allocate memory with default page size.

Parameters:

[in,out]	addr	- desired starting address of the region to allocate. If NULL, the system determines the appropriate location.On success, the actual allocated address is returned
	size	- the size of the region in bytes. For large pages, the size must be multiply of page size
	mode	- the bit mask of PORT_VMEM_MODE_* flags

apr_status_t port_vmem_free	(	void *	addr,
		size_t	size
	)

Releases previously reserved virtual memory region as a whole.

If the region was committed, the function first decommits it.

Parameters:

	addr	- the memory region address
	size	- size of the allocated memory

Returns:

APR_SUCCESS if OK; otherwise, an error code.

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