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GLAST/LAT > DAQ and FSW > FSW > Doxygen Index > PBS / V2-11-0

Constituent: pbs     Tag: mv2304

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MBA.h File Reference

Random memory allocation, function prototypes. More...

#include "PBS/impl/MBA.h.xx-xxx-xxx"

Include dependency graph for MBA.h:

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Data Structures
struct	_MBA_badBlock
	Definition of a bad block of memory. More...
Typedefs
typedef _MBA_badBlock	MBA_badBlock
	Typedef for struct _MBA_badBlock.
typedef PART_ID(*	MBA_create_cb )(void *prm)
	Function signature for a user definition initialization routine.
Functions
void *	MBA_align (unsigned int alignment, unsigned int nBytes)
	Allocates nBytes of aligned memory.
void *	MBA_alloc (unsigned int nBytes)
	Allocates nBytes of at least word aligned memory.
int	MBA_free (void *pBlock)
	Frees a piece of memory allocated with either MBA_align() or MBA_alloc().
int	MBA_statsGet (MBA_stats *stats)
	Gets the memory stats for the MBA partition.
int	MBA_initialize (MBA_create_cb create, void *prm)
	One time initialization of the MBA facility.

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Detailed Description

Random memory allocation, function prototypes.

Author:

JJRussell - russell@slac.stanford.edu

    CVS $Id: MBA.h,v 1.3 2005/05/12 19:42:56 russell Exp $

SYNOPSIS

This file acts as a front for malloc() and memalign() on host platforms and for memPartAlloc and memPartAlignedAlloc on VxWorks. Application level code should always use the equivalent M routines. On VxWork's platforms, malloc() and memalign(), by default, allocate out of the system partition. Because the VxWork's dynamic loader uses malloc() and because restrictions on the range of branch statements, the system partition must be limited to less than 24Mbytes.

With this in mind, FSW decided on a policy that discourages use of malloc() and memalign() in application code, effectively reserving the system partition for exclusive use by VxWorks itself.

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Typedef Documentation

MBA_badBlock

Typedef for struct _MBA_badBlock. A bad block is defined as a starting address and a length, in bytes. Typically one will specify a list of bad blocks. By convention, the list is terminated with a block specified with a beginning address of 0 and a length of 0. On embedded systems, MBA will remove bad blocks that fall within the range of its pool. This will be done at system initialization time. Unforturnately, there is no easy way to do this if the bad blocks fall within the system partition. It appears the only method here is to rebuild the kernel. Note: This should have been an easy job. One would have used the memory mapping registers to remap around the bad blocks. But, alas, the page registers do not work on the RAD750, hence this method.

PART_ID(* MBA_create_cb)(void *prm)

Function signature for a user definition initialization routine. Returns: The partition id Parameters: prm  Arbitrary user parameter While this function will get called back on non-VxWorks targets, it has no effect and is there simply for portability.

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Function Documentation

void * MBA_align (  unsigned int  alignment, unsigned int  nBytes )

Allocates nBytes of aligned memory. Parameters: alignment  The alignment factor. This must be a power of 2 nBytes  The number of bytes to allocate Returns: If successful, a pointer to the allocated memory, Else NULL Warning: Note that the calling sequence to this routine follows the convention of memalign(), not that of the VxWorks routine memPartAlign().

void * MBA_alloc (  unsigned int  nBytes  )

Allocates nBytes of at least word aligned memory. Parameters: nBytes  The number of bytes to allocate Returns: If successful, a pointer to the allocated memory, Else NULL

int MBA_free (  void *  pBlock  )

Frees a piece of memory allocated with either MBA_align() or MBA_alloc(). Parameters: pBlock  Pointer to the block of memory to be freed. Return values: 0,if  successful -1,if  error The return error codes are only supported on VxWorks platforms. On generic platforms, success is always returned. This is because free() does not give any indication of success or failure, whereas the VxWorks memPart routines do.

int MBA_initialize (  MBA_create_cb  create, void *  prm )

One time initialization of the MBA facility. Returns: Status Parameters: create  User callback partition creation meant to usurp the default creation routine in an extreme emergency prm  Arbitrary user parameter passed to partition creation routine. If the partition creation routine is specified as NULL, then, if this parameter is treated as a pointer to a list of bad blocks, MBA_badBlock. This is not meant to be a user callable routine.

int MBA_statsGet (  MBA_stats *  stats  )

Gets the memory stats for the MBA partition. Parameters: stats  Pointer to the statistics block to fill Return values: 0,if  successful -1,if  error On VXWORKS platforms, this is just a cover for memInfoGet. Warning: These statistics do not exist on generic platforms. The call interface is provided only as a convenience. On generic platforms, the caller should only use the contents for logging or display purposes. It is up to the caller to make his code portable across both a VXWORS and a generic platform. Additional advise. Even under VXWORKS, unless one can guarantee that the partition is not being used by another thread of execution at the time of call till the time one acts on a decision made as a result of examining the contents of the statistics block, then do not depend on the results of the call for anything more than logging or display purposes. Without the single-threaded constraint, the statistics can certainly change between the time one gathers the statistics and when one acts on them. Bottom line, this call should only ever be used for display or casual diagnostic reasons.

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