ACE_MMAP_Memory_Pool Class Reference

Make a memory pool that is based on mmap(2). This implementation allows memory to be shared between processes. More...

#include <MMAP_Memory_Pool.h>

Inheritance diagram for ACE_MMAP_Memory_Pool:

[legend]Collaboration diagram for ACE_MMAP_Memory_Pool:

[legend]List of all members.


Public Types
typedef ACE_MMAP_Memory_Pool_Options	OPTIONS
Public Member Functions
	ACE_MMAP_Memory_Pool (const ACE_TCHAR backing_store_name=0, const OPTIONS options=0)
	Initialize the pool.
virtual	~ACE_MMAP_Memory_Pool (void)
	Destructor.
virtual void *	init_acquire (size_t nbytes, size_t &rounded_bytes, int &first_time)
	Ask system for initial chunk of shared memory.
virtual void *	acquire (size_t nbytes, size_t &rounded_bytes)
virtual int	release (int destroy=1)
	Instruct the memory pool to release all of its resources.
virtual int	sync (ssize_t len=-1, int flags=MS_SYNC)
virtual int	sync (void *addr, size_t len, int flags=MS_SYNC)
	Sync the memory region to the backing store starting at addr.
virtual int	protect (ssize_t len=-1, int prot=PROT_RDWR)
virtual int	protect (void *addr, size_t len, int prot=PROT_RDWR)
virtual int	seh_selector (void *)
virtual int	remap (void *addr)
virtual void *	base_addr (void) const
	Return the base address of this memory pool.
virtual void	dump (void) const
	Dump the state of an object.
ACE_Mem_Map const &	mmap (void) const
	Get reference to underlying ACE_Mem_Map object.
ACE_Mem_Map &	mmap (void)
	Get reference to underlying ACE_Mem_Map object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Member Functions
virtual size_t	round_up (size_t nbytes)
virtual int	commit_backing_store_name (size_t rounded_bytes, ACE_LOFF_T &map_size)
virtual int	map_file (ACE_LOFF_T map_size)
	Memory map the file up to map_size bytes.
virtual int	handle_signal (int signum, siginfo_t , ucontext_t )
Protected Attributes
ACE_Sig_Handler	signal_handler_
	Handles SIGSEGV.
ACE_Mem_Map	mmap_
	Memory-mapping object.
void *	base_addr_
int	use_fixed_addr_
	Must we use the `base_addr_` or can we let mmap(2) select it?
int	flags_
	Flags passed into <ACE_OS::mmap>.
int	write_each_page_
ACE_LOFF_T	minimum_bytes_
	What the minimum bytes of the initial segment should be.
ACE_TCHAR	backing_store_name_ [MAXPATHLEN+1]
	Name of the backing store where the shared memory pool is kept.
bool	guess_on_fault_
LPSECURITY_ATTRIBUTES	sa_
	Security attributes object, only used on NT.
mode_t	file_mode_
	Protection mode for mmaped file.

Detailed Description

Make a memory pool that is based on mmap(2). This implementation allows memory to be shared between processes.

Member Typedef Documentation

typedef ACE_MMAP_Memory_Pool_Options ACE_MMAP_Memory_Pool::OPTIONS

Constructor & Destructor Documentation

ACE_MMAP_Memory_Pool::ACE_MMAP_Memory_Pool	(	const ACE_TCHAR *	backing_store_name = `0`,
		const OPTIONS *	options = `0`
	)

Initialize the pool.

ACE_MMAP_Memory_Pool::~ACE_MMAP_Memory_Pool ( void ) [virtual]

Destructor.

Member Function Documentation

void * ACE_MMAP_Memory_Pool::acquire	(	size_t	nbytes,
		size_t &	rounded_bytes
	)			`[virtual]`

Acquire at least nbytes from the memory pool. rounded_bytes is the actual number of bytes allocated. Also acquires an internal semaphore that ensures proper serialization of ACE_MMAP_Memory_Pool initialization across processes.

void * ACE_MMAP_Memory_Pool::base_addr ( void ) const [virtual]

Return the base address of this memory pool.

int ACE_MMAP_Memory_Pool::commit_backing_store_name	(	size_t	rounded_bytes,
		ACE_LOFF_T &	map_size
	)			`[protected, virtual]`

Compute the new map_size of the backing store and commit the memory.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL void ACE_MMAP_Memory_Pool::dump ( void ) const [virtual]

Dump the state of an object.

int ACE_MMAP_Memory_Pool::handle_signal	(	int	signum,
		siginfo_t *	,
		ucontext_t *
	)			`[protected, virtual]`

Handle SIGSEGV and SIGBUS signals to remap shared memory properly.

Reimplemented from ACE_Event_Handler.

void * ACE_MMAP_Memory_Pool::init_acquire	(	size_t	nbytes,
		size_t &	rounded_bytes,
		int &	first_time
	)			`[virtual]`

Ask system for initial chunk of shared memory.

int ACE_MMAP_Memory_Pool::map_file ( ACE_LOFF_T map_size ) [protected, virtual]

Memory map the file up to map_size bytes.

ACE_INLINE ACE_Mem_Map & ACE_MMAP_Memory_Pool::mmap ( void )

Get reference to underlying ACE_Mem_Map object.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE ACE_Mem_Map const & ACE_MMAP_Memory_Pool::mmap ( void ) const

Get reference to underlying ACE_Mem_Map object.

int ACE_MMAP_Memory_Pool::protect	(	void *	addr,
		size_t	len,
		int	prot = `PROT_RDWR`
	)			`[virtual]`

Change the protection of the pages of the mapped region to prot starting at addr up to len bytes.

int ACE_MMAP_Memory_Pool::protect	(	ssize_t	len = `-1`,
		int	prot = `PROT_RDWR`
	)			`[virtual]`

Change the protection of the pages of the mapped region to <prot> starting at <this->base_addr_> up to <len> bytes. If <len> == -1 then change protection of all pages in the mapped region.

int ACE_MMAP_Memory_Pool::release ( int destroy = 1 ) [virtual]

Instruct the memory pool to release all of its resources.

int ACE_MMAP_Memory_Pool::remap ( void * addr ) [virtual]

Try to extend the virtual address space so that addr is now covered by the address mapping. The method succeeds and returns 0 if the backing store has adequate memory to cover this address. Otherwise, it returns -1. This method is typically called by a UNIX signal handler for SIGSEGV or a Win32 structured exception when another process has grown the backing store (and its mapping) and our process now incurs a fault because our mapping isn't in range (yet).

size_t ACE_MMAP_Memory_Pool::round_up ( size_t nbytes ) [protected, virtual]

Implement the algorithm for rounding up the request to an appropriate chunksize.

int ACE_MMAP_Memory_Pool::seh_selector ( void * ) [virtual]

Win32 Structural exception selector. The return value decides how to handle memory pool related structural exceptions. Returns 1, 0, or , -1.

int ACE_MMAP_Memory_Pool::sync	(	void *	addr,
		size_t	len,
		int	flags = `MS_SYNC`
	)			`[virtual]`

Sync the memory region to the backing store starting at addr.

Reimplemented in ACE_Lite_MMAP_Memory_Pool.

int ACE_MMAP_Memory_Pool::sync	(	ssize_t	len = `-1`,
		int	flags = `MS_SYNC`
	)			`[virtual]`

Sync the memory region to the backing store starting at this->base_addr_.

Reimplemented in ACE_Lite_MMAP_Memory_Pool.

Member Data Documentation

ACE_MMAP_Memory_Pool::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

ACE_TCHAR ACE_MMAP_Memory_Pool::backing_store_name_[MAXPATHLEN+1] [protected]

Name of the backing store where the shared memory pool is kept.

void* ACE_MMAP_Memory_Pool::base_addr_ [protected]

Base of mapped region. If this has the value of 0 then the OS is free to select any address to map the file, otherwise this value is what the OS must try to use to mmap the file.

mode_t ACE_MMAP_Memory_Pool::file_mode_ [protected]

Protection mode for mmaped file.

int ACE_MMAP_Memory_Pool::flags_ [protected]

Flags passed into <ACE_OS::mmap>.

bool ACE_MMAP_Memory_Pool::guess_on_fault_ [protected]

Try to remap without knowing the faulting address. This parameter is ignored on platforms that know the faulting address (UNIX with SI_ADDR and Win32).

ACE_LOFF_T ACE_MMAP_Memory_Pool::minimum_bytes_ [protected]

What the minimum bytes of the initial segment should be.

ACE_Mem_Map ACE_MMAP_Memory_Pool::mmap_ [protected]

Memory-mapping object.

LPSECURITY_ATTRIBUTES ACE_MMAP_Memory_Pool::sa_ [protected]

Security attributes object, only used on NT.

ACE_Sig_Handler ACE_MMAP_Memory_Pool::signal_handler_ [protected]

Handles SIGSEGV.

int ACE_MMAP_Memory_Pool::use_fixed_addr_ [protected]

Must we use the base_addr_ or can we let mmap(2) select it?

int ACE_MMAP_Memory_Pool::write_each_page_ [protected]

Should we write a byte to each page to forceably allocate memory for this backing store?