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 (size_t len, int flags=MS_SYNC)
virtual int	sync (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 (size_t len, int prot=PROT_RDWR)
virtual int	protect (int prot=PROT_RDWR)
virtual int	protect (void *addr, size_t len, int prot=PROT_RDWR)
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, size_t &map_size)
virtual int	map_file (size_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().
bool	write_each_page_
size_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.
bool	install_signal_handler_
	Should we install a signal handler.

---

Detailed Description

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

Definition at line 136 of file MMAP_Memory_Pool.h.

---

Member Typedef Documentation

typedef ACE_MMAP_Memory_Pool_Options ACE_MMAP_Memory_Pool::OPTIONS

Definition at line 139 of file MMAP_Memory_Pool.h.

---

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.

Definition at line 116 of file MMAP_Memory_Pool.cpp.

References ACE_ERROR, ACE_SET_BITS, ACE_TEXT, ACE_TRACE, ACE_MMAP_Memory_Pool_Options::ALWAYS_FIXED, backing_store_name_, ACE_MMAP_Memory_Pool_Options::base_addr_, base_addr_, ACE_MMAP_Memory_Pool_Options::file_mode_, file_mode_, flags_, ACE_MMAP_Memory_Pool_Options::flags_, ACE::get_temp_dir(), ACE_MMAP_Memory_Pool_Options::guess_on_fault_, guess_on_fault_, ACE_MMAP_Memory_Pool_Options::install_signal_handler_, install_signal_handler_, LM_ERROR, MAXPATHLEN, ACE_MMAP_Memory_Pool_Options::minimum_bytes_, minimum_bytes_, ACE_OS::mktemp(), sa_, ACE_MMAP_Memory_Pool_Options::sa_, SIGSEGV, ACE_OS::strcat(), ACE_OS::strcpy(), ACE_OS::strsncpy(), ACE_MMAP_Memory_Pool_Options::unique_, ACE_MMAP_Memory_Pool_Options::use_fixed_addr_, use_fixed_addr_, ACE_MMAP_Memory_Pool_Options::write_each_page_, and write_each_page_.

  : base_addr_ (0),
    use_fixed_addr_(0),
    flags_ (MAP_SHARED),
    write_each_page_ (false),
    minimum_bytes_ (0),
    sa_ (0),
    file_mode_ (ACE_DEFAULT_FILE_PERMS),
    install_signal_handler_ (true)
{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::ACE_MMAP_Memory_Pool");

#if (defined (ACE_HAS_SIGINFO_T) && !defined (ACE_LACKS_SI_ADDR)) || defined (ACE_WIN32)
      // For plaforms that give the faulting address.
      guess_on_fault_ = false;
#else
      // For plaforms that do NOT give the faulting address, let the
      // options decide whether to guess or not.
      if (options)
        guess_on_fault_ = options->guess_on_fault_;
      else
        // If no options are specified, default to true.
        guess_on_fault_ = true;
#endif /* (defined (ACE_HAS_SIGINFO_T) && !defined (ACE_LACKS_SI_ADDR)) || defined (ACE_WIN32) */

  // Only change the defaults if <options> != 0.
  if (options)
    {
      if (options->flags_ != 0)
        this->flags_ = options->flags_;
      use_fixed_addr_ = options->use_fixed_addr_;

      if (use_fixed_addr_ == ACE_MMAP_Memory_Pool_Options::ALWAYS_FIXED)
        {
          this->base_addr_ = const_cast<void *> (options->base_addr_);
          ACE_SET_BITS (flags_, MAP_FIXED);
        }
      this->write_each_page_ = options->write_each_page_;
      this->minimum_bytes_ = options->minimum_bytes_;
      if (options->sa_ != 0)
        this->sa_ = options->sa_;
      this->file_mode_ = options->file_mode_;
      this->install_signal_handler_ = options->install_signal_handler_;
    }

  if (backing_store_name == 0)
    {
      // Only create a new unique filename for the backing store file
      // if the user didn't supply one...
#if defined (ACE_DEFAULT_BACKING_STORE)
      // Create a temporary file.
      ACE_OS::strcpy (this->backing_store_name_,
                      ACE_DEFAULT_BACKING_STORE);
#else /* ACE_DEFAULT_BACKING_STORE */
      if (ACE::get_temp_dir (this->backing_store_name_,
                             MAXPATHLEN - 17) == -1)
        // -17 for ace-malloc-XXXXXX
        {
          ACE_ERROR ((LM_ERROR,
                      ACE_TEXT ("Temporary path too long, ")
                      ACE_TEXT ("defaulting to current directory\n")));
          this->backing_store_name_[0] = 0;
        }

      // Add the filename to the end
      ACE_OS::strcat (this->backing_store_name_,
                      ACE_TEXT ("ace-malloc-XXXXXX"));

      // If requested an unique filename, use mktemp to get a random file.
      if (options && options->unique_)
        ACE_OS::mktemp(this->backing_store_name_);
#endif /* ACE_DEFAULT_BACKING_STORE */
    }
  else
    ACE_OS::strsncpy (this->backing_store_name_,
                      backing_store_name,
                      (sizeof this->backing_store_name_ / sizeof (ACE_TCHAR)));

#if !defined (ACE_WIN32)
  if (this->install_signal_handler_)
    {
      if (this->signal_handler_.register_handler (SIGSEGV, this) == -1)
        ACE_ERROR ((LM_ERROR,
                    "%p\n", this->backing_store_name_));
    }
#endif /* ACE_WIN32 */
}

ACE_MMAP_Memory_Pool::~ACE_MMAP_Memory_Pool

(

void

)

[virtual]

Destructor.

Definition at line 206 of file MMAP_Memory_Pool.cpp.

{
}

---

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.

Definition at line 328 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, mmap_, round_up(), and ACE_Mem_Map::size().

Referenced by init_acquire().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::acquire");
  rounded_bytes = this->round_up (nbytes);

  // ACE_DEBUG ((LM_DEBUG, "(%P|%t) acquiring more chunks, nbytes =
  // %B, rounded_bytes = %B\n", nbytes, rounded_bytes));

  size_t map_size;

  if (this->commit_backing_store_name (rounded_bytes,
                                       map_size) == -1)
    return 0;
  else if (this->map_file (map_size) == -1)
    return 0;

  // ACE_DEBUG ((LM_DEBUG, "(%P|%t) acquired more chunks, nbytes = %B,
  // rounded_bytes = %B, map_size = %B\n", nbytes, rounded_bytes,
  // map_size));

  return (void *) ((char *) this->mmap_.addr () + (this->mmap_.size () - rounded_bytes));
}

void * ACE_MMAP_Memory_Pool::base_addr

(

void

)

const [virtual]

Return the base address of this memory pool.

Definition at line 543 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, and base_addr_.

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::base_addr");
  return this->base_addr_;
}

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

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

Definition at line 213 of file MMAP_Memory_Pool.cpp.

References ACE_ERROR_RETURN, ACE_TEXT, ACE_TRACE, ACE_OS::fsync(), ACE_Mem_Map::handle(), LM_ERROR, ACE_OS::lseek(), mmap_, round_up(), and ACE_OS::write().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::commit_backing_store_name");

#if defined (__Lynx__)
  map_size = rounded_bytes;
#else
  size_t seek_len;

  if (this->write_each_page_)
    // Write to the end of every block to ensure that we have enough
    // space in the backing store.
    seek_len = this->round_up (1); // round_up(1) is one page.
  else
    // We're willing to risk it all in the name of efficiency...
    seek_len = rounded_bytes;

  // The following loop will execute multiple times (if
  // this->write_each_page == 1) or just once (if
  // this->write_each_page == 0).

  for (size_t cur_block = 0;
       cur_block < rounded_bytes;
       cur_block += seek_len)
    {
      map_size =
        ACE_Utils::truncate_cast<size_t> (
          ACE_OS::lseek (this->mmap_.handle (),
                         static_cast<ACE_OFF_T> (seek_len - 1),
                         SEEK_END));

      if (map_size == static_cast<size_t> (-1)
          || ACE_OS::write (this->mmap_.handle (),
                            "",
                            1) == -1)
        ACE_ERROR_RETURN ((LM_ERROR,
                           ACE_TEXT ("(%P|%t) %p\n"),
                           this->backing_store_name_),
                          -1);
    }

#if defined (ACE_OPENVMS)
  ::fsync(this->mmap_.handle());
#endif

  // Increment by one to put us at the beginning of the next chunk...
  ++map_size;
#endif /* __Lynx__ */
  return 0;
}

ACE_BEGIN_VERSIONED_NAMESPACE_DECL void ACE_MMAP_Memory_Pool::dump

(

void

)

const [virtual]

Dump the state of an object.

Definition at line 30 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE.

{
#if defined (ACE_HAS_DUMP)
  ACE_TRACE ("ACE_MMAP_Memory_Pool::dump");
#endif /* ACE_HAS_DUMP */
}

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

Handle SIGSEGV and SIGBUS signals to remap memory properly. When a process reads or writes to non-mapped memory a signal (SIGBUS or SIGSEGV) will be triggered. At that point, the ACE_Sig_Handler (which is part of the ACE_Reactor) will catch the signal and dispatch the handle_signal() method defined here. If the SIGSEGV signal occurred due to the fact that the mapping wasn't uptodate with respect to the backing store, the handler method below will update the mapping accordingly. When the signal handler returns, the instruction should be restarted and the operation should work.

Reimplemented from ACE_Event_Handler.

Definition at line 486 of file MMAP_Memory_Pool.cpp.

References ACE_DEBUG, ACE_TEXT, ACE_OS::filesize(), guess_on_fault_, LM_DEBUG, map_file(), and SIGSEGV.

{
  if (signum != SIGSEGV)
    return -1;
#if 0
  else
    ACE_DEBUG ((LM_DEBUG,  ACE_TEXT ("(%P|%t) received %S\n"), signum));
#endif
  // ACE_DEBUG ((LM_DEBUG,  ACE_TEXT ("(%P|%t) new mapping address = %@\n"), (char *) this->base_addr_ + current_map_size));

#if defined (ACE_HAS_SIGINFO_T) && !defined (ACE_LACKS_SI_ADDR)
  // Make sure that the pointer causing the problem is within the
  // range of the backing store.

  if (siginfo != 0)
    {
      // ACE_DEBUG ((LM_DEBUG,  ACE_TEXT ("(%P|%t) si_signo = %d, si_code = %d, addr = %@\n"), siginfo->si_signo, siginfo->si_code, siginfo->si_addr));
      if (this->remap ((void *) siginfo->si_addr) == -1)
        return -1;
      // ACE_ERROR_RETURN ((LM_ERROR, "(%P|%t) address %@ out of range\n",
      // siginfo->si_addr), -1);
      return 0;
    }
#else
  ACE_UNUSED_ARG(siginfo);
#endif /* ACE_HAS_SIGINFO_T && !defined ACE_LACKS_SI_ADDR */
  // If guess_on_fault_ is true, then we want to try to remap without
  // knowing the faulting address.  guess_on_fault_ can only be true
  // on platforms that do not provide the faulting address through
  // signals or exceptions.  We check to see if the mapping is up to
  // date. If it is, then this fault isn't due to this mapping and we
  // pass it on.
  if (guess_on_fault_)
    {
      // Check if the current mapping is up to date.
      size_t const current_map_size =
        ACE_Utils::truncate_cast<size_t> (ACE_OS::filesize (this->mmap_.handle ()));

      if (static_cast<size_t> (current_map_size) == this->mmap_.size ())
        {
          // The mapping is up to date so this really is a bad
          // address.  Thus, remove current signal handler so process
          // will fail with default action and core file will be
          // written.
          this->signal_handler_.remove_handler (SIGSEGV);
          return 0;
        }

      // Extend the mapping to cover the size of the backing store.
      return this->map_file (current_map_size);
    }
  else
    return -1;
}

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.

Definition at line 355 of file MMAP_Memory_Pool.cpp.

References ACE_ERROR_RETURN, ACE_SET_BITS, ACE_TEXT, ACE_TRACE, acquire(), ACE_Mem_Map::addr(), ACE_MMAP_Memory_Pool_Options::FIRSTCALL_FIXED, flags_, LM_ERROR, minimum_bytes_, mmap_, PROT_RDWR, ACE_Mem_Map::size(), and use_fixed_addr_.

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::init_acquire");

  first_time = 0;

  if (nbytes < static_cast <size_t> (this->minimum_bytes_))
    nbytes = static_cast <size_t> (this->minimum_bytes_);

  if (this->mmap_.open (this->backing_store_name_,
                        O_RDWR | O_CREAT | O_TRUNC | O_EXCL,
                        this->file_mode_, this->sa_) != -1)
    {
      // First time in, so need to acquire memory.
      first_time = 1;

      void *result = this->acquire (nbytes, rounded_bytes);
      // After the first time, reset the flag so that subsequent calls
      // will use MAP_FIXED
      if (use_fixed_addr_ == ACE_MMAP_Memory_Pool_Options::FIRSTCALL_FIXED)
        {
          ACE_SET_BITS (flags_, MAP_FIXED);
        }
      return result;
    }
  else if (errno == EEXIST)
    {
      errno = 0;
      // Reopen file *without* using O_EXCL...
      if (this->mmap_.map (this->backing_store_name_,
                           static_cast<size_t> (-1),
                           O_RDWR,
                           this->file_mode_,
                           PROT_RDWR,
                           this->flags_,
                           this->base_addr_,
                           0,
                           this->sa_) == -1)
        ACE_ERROR_RETURN ((LM_ERROR,
                           ACE_TEXT ("%p\n"),
                           ACE_TEXT ("MMAP_Memory_Pool::init_acquire, EEXIST")),
                          0);
      // After the first time, reset the flag so that subsequent calls
      // will use MAP_FIXED
      if (use_fixed_addr_ == ACE_MMAP_Memory_Pool_Options::FIRSTCALL_FIXED)
        {
          ACE_SET_BITS (flags_, MAP_FIXED);
        }
#if (ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1)
      // Update the mapped segment information
      ACE_BASED_POINTER_REPOSITORY::instance ()->bind (this->mmap_.addr(),
                                                       this->mmap_.size());
#endif /* ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1 */

      return this->mmap_.addr ();
    }
  else
    ACE_ERROR_RETURN ((LM_ERROR,
                       ACE_TEXT ("%p\n"),
                       ACE_TEXT ("MMAP_Memory_Pool::init_acquire")),
                      0);
}

int ACE_MMAP_Memory_Pool::map_file

(

size_t

map_size

)

[protected, virtual]

Memory map the file up to map_size bytes.

Definition at line 268 of file MMAP_Memory_Pool.cpp.

References ACE_ERROR, ACE_TEXT, ACE_TRACE, ACE_Mem_Map::addr(), backing_store_name_, base_addr_, LM_ERROR, mmap_, ACE_MMAP_Memory_Pool_Options::NEVER_FIXED, PROT_RDWR, ACE_Mem_Map::unmap(), and use_fixed_addr_.

Referenced by handle_signal(), and remap().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::map_file");
#if (ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1)
    void* obase_addr = this->base_addr_;
#endif /* ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1 */

  // Unmap the existing mapping.
  this->mmap_.unmap ();

#if (ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1)
  if (use_fixed_addr_ == ACE_MMAP_Memory_Pool_Options::NEVER_FIXED)
    this->base_addr_ = 0;
#endif /* ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1 */

  // Remap the file; try to stay at the same location as a previous mapping
  // but do not force it with MAP_FIXED. Doing so will give the OS permission
  // to map locations currently holding other things (such as the heap, or
  // the C library) into the map file, producing very unexpected results.
  if (this->mmap_.map (map_size,
                       PROT_RDWR,
                       this->flags_,
                       this->base_addr_,
                       0,
                       this->sa_) == -1
      || this->base_addr_ != 0
#ifdef ACE_HAS_WINCE
      && this->mmap_.addr () == 0)  // WinCE does not allow users to specify alloc addr.
#else
      && this->mmap_.addr () != this->base_addr_)
#endif  // ACE_HAS_WINCE
    {
#if 0
      ACE_ERROR ((LM_ERROR,
                  ACE_TEXT ("(%P|%t) addr = %@, base_addr = %@, map_size = %B, %p\n"),
                  this->mmap_.addr (),
                  this->base_addr_,
                  map_size,
                  this->backing_store_name_));
#endif /* 0 */
      return -1;
    }
  else
    {
#if (ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1)
      this->base_addr_ = this->mmap_.addr ();
      if(obase_addr && this->base_addr_ != obase_addr)
         ACE_BASED_POINTER_REPOSITORY::instance ()->unbind (obase_addr);
      ACE_BASED_POINTER_REPOSITORY::instance ()->bind (this->base_addr_,
                                                       map_size);
#endif /* ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1 */
      return 0;
    }
}

ACE_INLINE ACE_Mem_Map & ACE_MMAP_Memory_Pool::mmap

(

void

)

Get reference to underlying ACE_Mem_Map object.

Definition at line 16 of file MMAP_Memory_Pool.inl.

References mmap_.

{
  return mmap_;
}

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.

Definition at line 9 of file MMAP_Memory_Pool.inl.

References mmap_.

{
  return mmap_;
}

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.

Definition at line 110 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, and ACE_OS::mprotect().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::protect");
  return ACE_OS::mprotect (addr, len, prot);
}

int ACE_MMAP_Memory_Pool::protect

(

int

prot = PROT_RDWR

)

[virtual]

Change the protection of all the pages of the mapped region to prot starting at this->base_addr_.

Definition at line 95 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, ACE_OS::lseek(), mmap_, and ACE_Mem_Map::protect().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::protect");

  size_t const len = ACE_Utils::truncate_cast<size_t> (
    ACE_OS::lseek (this->mmap_.handle (), 0, SEEK_END));

  return this->mmap_.protect (len, prot);
}

int ACE_MMAP_Memory_Pool::protect	(	size_t	len,
		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.

Definition at line 87 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, mmap_, and ACE_Mem_Map::protect().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::protect");

  return this->mmap_.protect (len, prot);
}

int ACE_MMAP_Memory_Pool::release

(

int

destroy = 1

)

[virtual]

Instruct the memory pool to release all of its resources.

Definition at line 38 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, ACE_Mem_Map::close(), mmap_, and ACE_Mem_Map::remove().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::release");

#if (ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1)
  ACE_BASED_POINTER_REPOSITORY::instance ()->unbind (this->mmap_.addr ());
#endif /* ACE_HAS_POSITION_INDEPENDENT_POINTERS == 1 */

  if (destroy)
  this->mmap_.remove ();
  else
    this->mmap_.close ();
  return 0;
}

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).

Definition at line 440 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, ACE_OS::filesize(), and map_file().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::remap");
  //  ACE_DEBUG ((LM_DEBUG,  ACE_TEXT ("Remapping with fault address at: %@\n"), addr));
  size_t const current_map_size =
    ACE_Utils::truncate_cast<size_t> (ACE_OS::filesize (this->mmap_.handle ()));
  // ACE_OS::lseek (this->mmap_.handle (), 0, SEEK_END);

  if (!(addr < (void *) ((char *) this->mmap_.addr () + current_map_size)
        && addr >= this->mmap_.addr ()))
    return -1;

  // Extend the mapping to cover the size of the backing store.
  return this->map_file (current_map_size);
}

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.

Definition at line 550 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, and ACE::round_to_pagesize().

Referenced by acquire(), and commit_backing_store_name().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::round_up");
  return ACE::round_to_pagesize (nbytes);
}

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.

Definition at line 76 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, and ACE_OS::msync().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::sync");
  return ACE_OS::msync (addr, len, flags);
}

int ACE_MMAP_Memory_Pool::sync

(

int

flags = MS_SYNC

)

[virtual]

Sync the memory region to the backing store starting at this->base_addr_. Will sync as much as the backing file allows.

Reimplemented in ACE_Lite_MMAP_Memory_Pool.

Definition at line 62 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, ACE_OS::lseek(), mmap_, and ACE_Mem_Map::sync().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::sync");

  size_t const len = ACE_Utils::truncate_cast<size_t> (
    ACE_OS::lseek (this->mmap_.handle (), 0, SEEK_END));

  return this->mmap_.sync (len, flags);
}

int ACE_MMAP_Memory_Pool::sync	(	size_t	len,
		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.

Definition at line 54 of file MMAP_Memory_Pool.cpp.

References ACE_TRACE, mmap_, and ACE_Mem_Map::sync().

{
  ACE_TRACE ("ACE_MMAP_Memory_Pool::sync");

  return this->mmap_.sync (len, flags);
}

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Member Data Documentation

ACE_MMAP_Memory_Pool::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Definition at line 230 of file MMAP_Memory_Pool.h.

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

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

Definition at line 289 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), and map_file().

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.

Definition at line 273 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), base_addr(), and map_file().

mode_t ACE_MMAP_Memory_Pool::file_mode_ [protected]

Protection mode for mmaped file.

Definition at line 302 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool().

int ACE_MMAP_Memory_Pool::flags_ [protected]

Flags passed into ACE_OS::mmap().

Definition at line 279 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), and init_acquire().

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).

Definition at line 296 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), and handle_signal().

bool ACE_MMAP_Memory_Pool::install_signal_handler_ [protected]

Should we install a signal handler.

Definition at line 305 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool().

size_t ACE_MMAP_Memory_Pool::minimum_bytes_ [protected]

What the minimum bytes of the initial segment should be.

Definition at line 286 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), and init_acquire().

ACE_Mem_Map ACE_MMAP_Memory_Pool::mmap_ [protected]

Memory-mapping object.

Definition at line 266 of file MMAP_Memory_Pool.h.

Referenced by acquire(), commit_backing_store_name(), init_acquire(), map_file(), mmap(), protect(), release(), and sync().

LPSECURITY_ATTRIBUTES ACE_MMAP_Memory_Pool::sa_ [protected]

Security attributes object, only used on NT.

Definition at line 299 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool().

ACE_Sig_Handler ACE_MMAP_Memory_Pool::signal_handler_ [protected]

Handles SIGSEGV.

Definition at line 262 of file MMAP_Memory_Pool.h.

int ACE_MMAP_Memory_Pool::use_fixed_addr_ [protected]

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

Definition at line 276 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool(), init_acquire(), and map_file().

bool ACE_MMAP_Memory_Pool::write_each_page_ [protected]

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

Definition at line 283 of file MMAP_Memory_Pool.h.

Referenced by ACE_MMAP_Memory_Pool().

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

• MMAP_Memory_Pool.h
• MMAP_Memory_Pool.cpp
• MMAP_Memory_Pool.inl

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