DMA_RELEASE_FROM_COH(9) Device drivers infrastructure DMA_RELEASE_FROM_COH(9)NAME
dma_release_from_coherent - try to free the memory allocated from per-device coherent memory pool
SYNOPSIS
int dma_release_from_coherent(struct device * dev, int order, void * vaddr);
ARGUMENTS
dev
device from which the memory was allocated
order
the order of pages allocated
vaddr
virtual address of allocated pages
DESCRIPTION
This checks whether the memory was allocated from the per-device coherent memory pool and if so, releases that memory.
Returns 1 if we correctly released the memory, or 0 if dma_release_coherent should proceed with releasing memory from generic pools.
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 DMA_RELEASE_FROM_COH(9)
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ost::MemPager(3) Library Functions Manual ost::MemPager(3)NAME
ost::MemPager -
The memory pager is used to allocate cumulative memory pages for storing object specific 'persistant' data that is presumed to persist
during the life of a given derived object.
SYNOPSIS
#include <misc.h>
Inherited by ost::Keydata [protected], ost::SharedMemPager, and ost::StackPager [protected].
Classes
struct _page
Public Member Functions
int getPages (void)
Return the total number of pages that have been allocated for this memory pool.
Protected Member Functions
virtual void * first (size_t size)
Allocate first workspace from paged memory.
virtual void * alloc (size_t size)
Allocate memory from either the currently active page, or allocate a new page for the object.
char * first (char *str)
Allocate a string from the memory pager pool and copy the string into it's new memory area.
char * alloc (const char *str)
Allocate a string from the memory pager pool and copy the string inti it's new memory area.
MemPager (size_t pagesize=4096)
Create a paged memory pool for cumulative storage.
void purge (void)
purge the current memory pool.
void clean (void)
Clean for memory cleanup before exiting.
virtual ~MemPager ()
Delete the memory pool and all allocated memory.
Friends
class String
class MemPagerObject
Detailed Description
The memory pager is used to allocate cumulative memory pages for storing object specific 'persistant' data that is presumed to persist
during the life of a given derived object.
When the object is destroyed, all accumulated data is automatically purged.
There are a number of odd and specialized utility classes found in Common C++. The most common of these is the 'MemPager' class. This is
basically a class to enable page-grouped 'cumulative' memory allocation; all accumulated allocations are dropped during the destructor.
This class has found it's way in a lot of other utility classes in Common C++.
Author:
David Sugar dyfet@ostel.com Accumulative object memory allocator.
Constructor &; Destructor Documentation
ost::MemPager::MemPager (size_tpagesize = 4096) [protected]
Create a paged memory pool for cumulative storage. This pool allocates memory in fixed 'pagesize' chunks. Ideal performance is achived when
the pool size matches the system page size. This pool can only exist in derived objects.
Parameters:
pagesize page size to allocate chunks.
virtual ost::MemPager::~MemPager () [protected], [virtual]
Delete the memory pool and all allocated memory.
Member Function Documentation
virtual void* ost::MemPager::alloc (size_tsize) [protected], [virtual]
Allocate memory from either the currently active page, or allocate a new page for the object. Parameters:
size size of memory to allocate.
Returns:
pointer to allocated memory.
Reimplemented in ost::SharedMemPager.
char* ost::MemPager::alloc (const char *str) [protected]
Allocate a string from the memory pager pool and copy the string inti it's new memory area. This checks only the last active page for
available space before allocating a new page.
Parameters:
str string to allocate and copy into paged memory pool.
Returns:
copy of string from allocated memory.
void ost::MemPager::clean (void) [protected]
Clean for memory cleanup before exiting.
virtual void* ost::MemPager::first (size_tsize) [protected], [virtual]
Allocate first workspace from paged memory. This method scans all currently allocated blocks for available space before adding new pages
and hence is both slower and more efficient.
Parameters:
size size of memory to allocate.
Returns:
pointer to allocated memory.
Reimplemented in ost::SharedMemPager.
char* ost::MemPager::first (char *str) [protected]
Allocate a string from the memory pager pool and copy the string into it's new memory area. This method allocates memory by first searching
for an available page, and then allocating a new page if no space is found.
Parameters:
str string to allocate and copy into paged memory pool.
Returns:
copy of string from allocated memory.
int ost::MemPager::getPages (void) [inline]
Return the total number of pages that have been allocated for this memory pool. Returns:
number of pages allocated.
void ost::MemPager::purge (void) [protected]
purge the current memory pool.
Reimplemented in ost::SharedMemPager, and ost::StackPager.
Friends And Related Function Documentation
friend class MemPagerObject [friend]
friend class String [friend]
Author
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GNU CommonC++ Sat Jun 23 2012 ost::MemPager(3)