buddysystem.h File Reference

Buddy System. More...

Go to the source code of this file.

Classes
struct	bb_page_t
	The base structure representing a bb page. More...
struct	bb_free_area_t
	Buddy system descriptor: collection of free page blocks. Each block represents 2^k free contiguous page. More...
struct	bb_instance_t
	Buddy system instance, that represents a memory area managed by the buddy system. More...

Macros
#define	MAX_BUDDYSYSTEM_GFP_ORDER   14
	Max gfp pages order of buddysystem blocks.
#define	BBSTRUCT_OFFSET(page, element)    ((uint32_t) & (((page *)NULL)->element))
	Provide the offset of the element inside the given type of page.
#define	PG_FROM_BBSTRUCT(bbstruct, page, element)    ((page *)(((uint32_t)(bbstruct)) - BBSTRUCT_OFFSET(page, element)))
	Returns the address of the given element of a given type of page, based on the provided bbstruct.

Typedefs
typedef struct bb_page_t	bb_page_t
	The base structure representing a bb page.
typedef struct bb_free_area_t	bb_free_area_t
	Buddy system descriptor: collection of free page blocks. Each block represents 2^k free contiguous page.
typedef struct bb_instance_t	bb_instance_t
	Buddy system instance, that represents a memory area managed by the buddy system.

Functions
bb_page_t *	bb_alloc_pages (bb_instance_t *instance, unsigned int order)
	Allocate a block of page frames of size 2^order. More...
void	bb_free_pages (bb_instance_t *instance, bb_page_t *page)
	Free a block of page frames of size 2^order. More...
bb_page_t *	bb_alloc_page_cached (bb_instance_t *instance)
	Alloc a page using bb cache. More...
void	bb_free_page_cached (bb_instance_t *instance, bb_page_t *page)
	Free a page allocated with bb_alloc_page_cached. More...
void	buddy_system_init (bb_instance_t *instance, const char *name, void *pages_start, uint32_t bbpage_offset, uint32_t pages_stride, uint32_t pages_count)
	Initialize Buddy System. More...
void	buddy_system_dump (bb_instance_t *instance)
	Print the size of free_list of each free_area. More...
unsigned long	buddy_system_get_total_space (bb_instance_t *instance)
	Returns the total space for the given instance. More...
unsigned long	buddy_system_get_free_space (bb_instance_t *instance)
	Returns the free space for the given instance. More...
unsigned long	buddy_system_get_cached_space (bb_instance_t *instance)
	Returns the cached space for the given instance. More...

Detailed Description

Buddy System.

Copyright

(c) 2014-2024 This file is distributed under the MIT License. See LICENSE.md for details.

Function Documentation

bb_alloc_page_cached()

bb_page_t* bb_alloc_page_cached

(

bb_instance_t *

instance

)

Alloc a page using bb cache.

Parameters

instance

Buddy system instance.

Returns

An allocated page.

bb_alloc_pages()

bb_page_t* bb_alloc_pages	(	bb_instance_t *	instance,
		unsigned int	order
	)

Allocate a block of page frames of size 2^order.

Parameters

instance	A buddy system instance.
order	The logarithm of the size of the block.

Returns

The address of the first page descriptor of the block, or NULL.

bb_free_page_cached()

void bb_free_page_cached	(	bb_instance_t *	instance,
		bb_page_t *	page
	)

Free a page allocated with bb_alloc_page_cached.

Parameters

instance	Buddy system instance.
page	The address of the first page descriptor of the block.

bb_free_pages()

void bb_free_pages	(	bb_instance_t *	instance,
		bb_page_t *	page
	)

Free a block of page frames of size 2^order.

Parameters

instance	A buddy system instance.
page	The address of the first page descriptor of the block.

buddy_system_dump()

void buddy_system_dump

(

bb_instance_t *

instance

)

Print the size of free_list of each free_area.

Parameters

instance

A buddy system instance.

buddy_system_get_cached_space()

unsigned long buddy_system_get_cached_space

(

bb_instance_t *

instance

)

Returns the cached space for the given instance.

Parameters

instance

A buddy system instance.

Returns

The requested total sapce.

buddy_system_get_free_space()

unsigned long buddy_system_get_free_space

(

bb_instance_t *

instance

)

Returns the free space for the given instance.

Parameters

instance

A buddy system instance.

Returns

The requested total sapce.

buddy_system_get_total_space()

unsigned long buddy_system_get_total_space

(

bb_instance_t *

instance

)

Returns the total space for the given instance.

Parameters

instance

A buddy system instance.

Returns

The requested total sapce.

buddy_system_init()

void buddy_system_init	(	bb_instance_t *	instance,
		const char *	name,
		void *	pages_start,
		uint32_t	bbpage_offset,
		uint32_t	pages_stride,
		uint32_t	pages_count
	)

Initialize Buddy System.

Parameters

instance	A buddysystem instance.
name	The name of the current instance (for debug purposes)
pages_start	The start address of the page structures
bbpage_offset	The offset from the start of the whole page of the bb_page_t struct.
pages_stride	The (padded) size of the whole page structure
pages_count	The number of pages in this region