slab.h File Reference

Functions and structures for managing memory slabs. More...

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Classes
struct	kmem_cache_t
	Stores the information of a cache. More...

Macros
#define	KMEM_CREATE(objtype)    kmem_cache_create(#objtype, sizeof(objtype), alignof(objtype), GFP_KERNEL, NULL, NULL)
	Create a new cache.
#define	KMEM_CREATE_CTOR(objtype, ctor)    kmem_cache_create(#objtype, sizeof(objtype), alignof(objtype), GFP_KERNEL, (kmem_fun_t)(ctor), NULL)
	Creates a new cache and allows to specify the constructor.

Typedefs
typedef unsigned int	slab_flags_t
	Type for slab flags.
typedef void(*	kmem_fun_t) (void *)
	Type of function used as constructor/destructor for cache creation and destruction.
typedef struct kmem_cache_t	kmem_cache_t
	Stores the information of a cache.

Functions
int	kmem_cache_init (void)
	Initializes the kernel memory cache system. More...
kmem_cache_t *	kmem_cache_create (const char *name, unsigned int size, unsigned int align, slab_flags_t flags, kmem_fun_t ctor, kmem_fun_t dtor)
	Creates a new kmem_cache structure. More...
int	kmem_cache_destroy (kmem_cache_t *cachep)
	Destroys a specified kmem_cache structure. More...
void *	kmem_cache_alloc (kmem_cache_t *cachep, gfp_t flags)
	Allocates an object from the specified kmem_cache_t. More...
void	kmem_cache_free (void *addr)
	Frees an object previously allocated from a kmem_cache_t. More...
void *	kmalloc (unsigned int size)
	Allocates memory of the specified size using kmalloc. More...
void	kfree (void *ptr)
	Frees memory allocated by kmalloc or kmem_cache_alloc. More...

Detailed Description

Functions and structures for managing memory slabs.

Copyright

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

Function Documentation

kfree()

void kfree

(

void *

ptr

)

Frees memory allocated by kmalloc or kmem_cache_alloc.

Parameters

ptr	Pointer to the memory to free.

kmalloc()

void* kmalloc

(

unsigned int

size

)

Allocates memory of the specified size using kmalloc.

Parameters

size	Size of the memory to allocate.

Returns

Pointer to the allocated memory, or NULL if allocation fails.

kmem_cache_alloc()

void* kmem_cache_alloc	(	kmem_cache_t *	cachep,
		gfp_t	flags
	)

Allocates an object from the specified kmem_cache_t.

Parameters

cachep	Pointer to the cache from which to allocate the object.
flags	Flags for the allocation (e.g., GFP_KERNEL).

Returns

Pointer to the allocated object, or NULL if allocation fails.

kmem_cache_create()

kmem_cache_t* kmem_cache_create	(	const char *	name,
		unsigned int	size,
		unsigned int	align,
		slab_flags_t	flags,
		kmem_fun_t	ctor,
		kmem_fun_t	dtor
	)

Creates a new kmem_cache structure.

This function allocates memory for a new cache and initializes it with the provided parameters. The cache is ready for use after this function returns.

Parameters

name	Name of the cache.
size	Size of each object in the cache.
align	Alignment requirement for objects in the cache.
flags	Flags for slab allocation.
ctor	Constructor function for initializing objects (can be NULL).
dtor	Destructor function for cleaning up objects (can be NULL).

Returns

Pointer to the newly created kmem_cache_t, or NULL if allocation fails.

kmem_cache_destroy()

int kmem_cache_destroy

(

kmem_cache_t *

cachep

)

Destroys a specified kmem_cache structure.

This function cleans up and frees all memory associated with the specified cache, including all associated slab pages. After calling this function, the cache should no longer be used.

Parameters

cachep

Pointer to the kmem_cache_t structure to destroy.

Returns

Returns 0 on success, or -1 if an error occurs.

kmem_cache_free()

void kmem_cache_free

(

void *

addr

)

Frees an object previously allocated from a kmem_cache_t.

Parameters

addr	Pointer to the object to free.

kmem_cache_init()

int kmem_cache_init

(

void

)

Initializes the kernel memory cache system.

This function initializes the global cache list and creates the main cache for managing kmem_cache_t structures. It also creates caches for different order sizes for kmalloc allocations.

Note

This function should be called during system initialization.

Returns

Returns 0 on success, or -1 if an error occurs.