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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 <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 Methods
	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.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Methods
virtual size_t	round_up (size_t nbytes)
virtual int	commit_backing_store_name (size_t rounded_bytes, off_t &map_size)
virtual int	map_file (off_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_
off_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.
int	guess_on_fault_
LPSECURITY_ATTRIBUTES	sa_
	Security attributes object, only used on NT.
mode_t	file_mode_
	Protection mode for mmaped file.

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Detailed Description

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

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Member Typedef Documentation

typedef ACE_MMAP_Memory_Pool_Options ACE_MMAP_Memory_Pool::OPTIONS

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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_INLINE ACE_MMAP_Memory_Pool::~ACE_MMAP_Memory_Pool (  void    )  [virtual]

Destructor.

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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.

ACE_INLINE 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, off_t &    map_size )  [protected, virtual]

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

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 (  off_t    map_size )  [protected, virtual]

Memory map the file up to <map_size> bytes.

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).

ACE_INLINE 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.

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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>.

int 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).

off_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?

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The documentation for this class was generated from the following files:

• Memory_Pool.h
• Memory_Pool.cpp
• Memory_Pool.i

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