@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / storage / ipc / ipci . c , v 1.64 2004 / 02 / 10 01 : 55 : 25 tgl Exp $
* $ PostgreSQL : pgsql / src / backend / storage / ipc / ipci . c , v 1.65 2004 / 02 / 25 19 : 41 : 22 momjian Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -36,8 +36,10 @@
* Creates and initializes shared memory and semaphores .
*
* This is called by the postmaster or by a standalone backend .
* It is NEVER called by a backend forked from the postmaster ;
* for such a backend , the shared memory is already ready - to - go .
* It is also called by a backend forked from the postmaster under
* the EXEC_BACKEND case
*
* In the non EXEC_BACKEND case , backends already have shared memory ready - to - go .
*
* If " makePrivate " is true then we only need private memory , not shared
* memory . This is true for a standalone backend , false for a postmaster .
@ -47,53 +49,68 @@ CreateSharedMemoryAndSemaphores(bool makePrivate,
int maxBackends ,
int port )
{
int size ;
int numSemas ;
PGShmemHeader * seghdr ;
/*
* Size of the Postgres shared - memory block is estimated via
* moderately - accurate estimates for the big hogs , plus 100 K for the
* stuff that ' s too small to bother with estimating .
*/
size = BufferShmemSize ( ) ;
size + = LockShmemSize ( maxBackends ) ;
size + = XLOGShmemSize ( ) ;
size + = CLOGShmemSize ( ) ;
size + = LWLockShmemSize ( ) ;
size + = SInvalShmemSize ( maxBackends ) ;
size + = FreeSpaceShmemSize ( ) ;
PGShmemHeader * seghdr = NULL ;
if ( ! IsUnderPostmaster )
{
int size ;
int numSemas ;
/*
* Size of the Postgres shared - memory block is estimated via
* moderately - accurate estimates for the big hogs , plus 100 K for the
* stuff that ' s too small to bother with estimating .
*/
size = BufferShmemSize ( ) ;
size + = LockShmemSize ( maxBackends ) ;
size + = XLOGShmemSize ( ) ;
size + = CLOGShmemSize ( ) ;
size + = LWLockShmemSize ( ) ;
size + = SInvalShmemSize ( maxBackends ) ;
size + = FreeSpaceShmemSize ( ) ;
# ifdef EXEC_BACKEND
size + = ShmemBackendArraySize ( ) ;
size + = ShmemBackendArraySize ( ) ;
# endif
size + = 100000 ;
/* might as well round it off to a multiple of a typical page size */
size + = 8192 - ( size % 8192 ) ;
elog ( DEBUG3 , " invoking IpcMemoryCreate(size=%d) " , size ) ;
size + = 100000 ;
/* might as well round it off to a multiple of a typical page size */
size + = 8192 - ( size % 8192 ) ;
elog ( DEBUG3 , " invoking IpcMemoryCreate(size=%d) " , size ) ;
/*
* Create the shmem segment
*/
seghdr = PGSharedMemoryCreate ( size , makePrivate , port ) ;
/*
* Create semaphores
*/
numSemas = ProcGlobalSemas ( maxBackends ) ;
numSemas + = SpinlockSemas ( ) ;
PGReserveSemaphores ( numSemas , port ) ;
}
else
{
/*
* Attach to the shmem segment .
* ( this should only ever be reached by EXEC_BACKEND code ,
* and only then with makePrivate = = false )
*/
Assert ( ExecBackend & & ! makePrivate ) ;
seghdr = PGSharedMemoryCreate ( - 1 , makePrivate , 0 ) ;
}
/*
* Create the shmem segment
*/
seghdr = PGSharedMemoryCreate ( size , makePrivate , port ) ;
/*
* Create semaphores
*/
numSemas = ProcGlobalSemas ( maxBackends ) ;
numSemas + = SpinlockSemas ( ) ;
PGReserveSemaphores ( numSemas , port ) ;
/*
* Set up shared memory allocation mechanism
*/
InitShmemAllocation ( seghdr , true ) ;
InitShmemAllocation ( seghdr , ! IsUnderPostmaster ) ;
/*
* Now initialize LWLocks , which do shared memory allocation and are
* needed for InitShmemIndex .
*/
CreateLWLocks ( ) ;
if ( ! IsUnderPostmaster )
CreateLWLocks ( ) ;
/*
* Set up shmem . c index hashtable
@ -137,41 +154,7 @@ CreateSharedMemoryAndSemaphores(bool makePrivate,
/*
* Alloc the win32 shared backend array
*/
ShmemBackendArrayAllocation ( ) ;
if ( ! IsUnderPostmaster )
ShmemBackendArrayAllocation ( ) ;
# endif
}
# ifdef EXEC_BACKEND
/*
* AttachSharedMemoryAndSemaphores
* Attaches to the existing shared resources .
*/
/* FIXME: [fork/exec] This function is starting to look pretty much like
CreateSharedMemoryAndSemaphores . Refactor ? */
void
AttachSharedMemoryAndSemaphores ( void )
{
PGShmemHeader * seghdr = PGSharedMemoryCreate ( - 1 , false , - 1 ) ;
InitShmemAllocation ( seghdr , false ) ;
InitShmemIndex ( ) ;
XLOGShmemInit ( ) ;
CLOGShmemInit ( ) ;
InitBufferPool ( ) ;
InitLocks ( ) ;
InitLockTable ( MaxBackends ) ;
InitProcGlobal ( MaxBackends ) ;
CreateSharedInvalidationState ( MaxBackends ) ;
InitFreeSpaceMap ( ) ;
PMSignalInit ( ) ;
}
# endif
Bruce Momjian
22 years ago