backend/mmapcache.h File Reference

---

Detailed Description

Mmapcache stores a MRU cache of all established mmaped memory regions which are currently not in use.

The mmapcache also manages the upper limit about how much memory can be mmaped.

Definition in file mmapcache.h.

#include "lib/error.h"
#include "lib/mrucache.h"
#include "lib/mutex.h"
#include "backend/mmap.h"
#include <nobug.h>

Include dependency graph for mmapcache.h:

Go to the source code of this file.

Classes
struct	lumiera_mmapcache_struct
Typedefs
typedef struct lumiera_mmapcache_struct	lumiera_mmapcache
typedef lumiera_mmapcache *	LumieraMMapcache
Functions
int	lumiera_mmapcache_age (LumieraMMapcache self)
	Destroy and free the nelem oldest elements.
void	lumiera_mmapcache_announce (LumieraMMapcache self, LumieraMMap map)
	Announce a new mmap object to the cache quotas.
void	lumiera_mmapcache_checkin (LumieraMMapcache self, LumieraMMap handle)
	Put a mmap into the cache Mmaps which are checked in are subject of cache aging and might get destroyed and reused.
LumieraMMap	lumiera_mmapcache_checkout (LumieraMMapcache self, LumieraMMap handle)
	Remove a mmap from cache aging Mmaps which are subject of cache aging must be checked out before they can be used.
void	lumiera_mmapcache_delete (void)
	Delete the mmap cache.
void	lumiera_mmapcache_forget (LumieraMMapcache self, LumieraMMap map)
	Remove a mmap object from the cache quotas.
LumieraMMap	lumiera_mmapcache_mmap_acquire (LumieraMMapcache self)
	Get a fresh mmap object.
void	lumiera_mmapcache_new (size_t limit)
	Initializes the mmapcache.
Variables
LumieraMMapcache	lumiera_mcache

---

Function Documentation

void lumiera_mmapcache_new

(

size_t

limit

)

Initializes the mmapcache.

Parameters:

limit

the mmapcache will drop elements when the sum of all mmapings gives over limit

void lumiera_mmapcache_delete

(

void

)

Delete the mmap cache.

No mmaps in the cache must be locked, this would be a fatal error. The handles are closed automatically.

LumieraMMap lumiera_mmapcache_mmap_acquire

(

LumieraMMapcache

self

)

Get a fresh mmap object.

when mmaped_limit is reached, the oldest mmap object gets dropped else a new allocated object is returned

Parameters:

self

pointer to the cache

Returns:

the new mmap

void lumiera_mmapcache_announce	(	LumieraMMapcache	self,
		LumieraMMap	map
	)

Announce a new mmap object to the cache quotas.

Update the statistics kept in the cache, the map object is still considered to be checked out

Parameters:

	self	pointer to the cache
	map	object to be announced

void lumiera_mmapcache_forget	(	LumieraMMapcache	self,
		LumieraMMap	map
	)

Remove a mmap object from the cache quotas.

Update the statistics kept in the cache, called by mmap's destructor only

Parameters:

	self	pointer to the cache
	map	object to be removed

int lumiera_mmapcache_age

(

LumieraMMapcache

self

)

Destroy and free the nelem oldest elements.

Used to free up resources and memory.

Parameters:

self

cache where to free elements.

Returns:

nelem-(numer of elements which got freed), that is 0 if all requested elements got freed

LumieraMMap lumiera_mmapcache_checkout	(	LumieraMMapcache	self,
		LumieraMMap	handle
	)

Remove a mmap from cache aging Mmaps which are subject of cache aging must be checked out before they can be used.

Parameters:

	self	the mmapcache
	handle	the mmap to be checked out

void lumiera_mmapcache_checkin	(	LumieraMMapcache	self,
		LumieraMMap	handle
	)

Put a mmap into the cache Mmaps which are checked in are subject of cache aging and might get destroyed and reused.

Parameters:

	self	the mmapcache
	handle	the mmap to be checked in