buddy.h File Reference

Buddy-system memory allocator.

#include <stdint.h>
#include <sys/queue.h>

Go to the source code of this file.

Data Structures
struct	buddy_list
struct	buddy_list_bucket

Macros
#define	BUDDY_ALIGN_PREF   (32 - 2 * sizeof(void*) - sizeof(uint32_t) - sizeof(purpose_t))

Typedefs
typedef enum purpose	purpose_t
typedef struct buddy_list	buddy_list_t
typedef enum valid	valid_t
typedef struct buddy_list_bucket	buddy_list_bucket_t

Enumerations
enum	purpose { FREE , USED }
enum	valid { VALID , INVALID }

Functions
buddy_list_bucket_t *	create_buddy_table (unsigned int power_of_two)
void *	buddy_alloc (unsigned size)
void	buddy_free (void *ptr)

Macro Definition Documentation

BUDDY_ALIGN_PREF

#define BUDDY_ALIGN_PREF   (32 - 2 * sizeof(void*) - sizeof(uint32_t) - sizeof(purpose_t))

Definition at line 14 of file buddy.h.

Typedef Documentation

buddy_list_bucket_t

typedef struct buddy_list_bucket buddy_list_bucket_t

Bucket of 2^order sized free memory blocks.

buddy_list_t

typedef struct buddy_list buddy_list_t

Metadata about this particular block (and stored at the beginning of this block). One per allocated block of memory. Should be 32 bytes to not screw up alignment.

purpose_t

typedef enum purpose purpose_t

valid_t

typedef enum valid valid_t

Enumeration Type Documentation

purpose

enum purpose

Enumerator
FREE
USED

Definition at line 12 of file buddy.h.

valid

enum valid

Enumerator
VALID
INVALID

Definition at line 31 of file buddy.h.

Function Documentation

buddy_alloc()

void * buddy_alloc

(

unsigned

size

)

Find the smallest block that will contain size and return it. Note this returns the memory allocated and usable, not the entire buffer. This may involve breaking up larger blocks.

Parameters

size	The size of the data this allocation must be able to hold.

Definition at line 234 of file buddy.c.

References buddy_split(), buddy_list_bucket::count, g_tw_buddy_master, INVALID, buddy_list_bucket::is_valid, next_power2(), buddy_list_bucket::order, tw_error(), TW_LOC, buddy_list::use, and USED.

Referenced by tw_snapshot_delta().

buddy_free()

void buddy_free

(

void *

ptr

)

Free the given pointer (and coalesce it with its buddy if possible).

Parameters

ptr	The pointer to free.

Definition at line 137 of file buddy.c.

References buddy_try_merge(), buddy_list_bucket::count, FREE, g_tw_buddy_master, buddy_list_bucket::order, buddy_list::size, TW_LOC, tw_printf(), buddy_list::use, and USED.

Referenced by tw_event_free(), tw_event_rollback(), and tw_eventq_push_list().

create_buddy_table()

buddy_list_bucket_t * create_buddy_table

(

unsigned int

power_of_two

)

Pass in the power of two e.g., passing 5 will yield 2^5 = 32.

Parameters

power_of_two

The largest "order" this table will support.

<Minimum block order

<Minimum block order

<Minimum block order

<Minimum block order

Definition at line 288 of file buddy.c.

References buddy_base_address, BUDDY_BLOCK_ORDER, buddy_list_bucket::count, FREE, INVALID, buddy_list_bucket::is_valid, buddy_list_bucket::order, buddy_list::size, tw_calloc(), TW_LOC, buddy_list::use, and VALID.

Referenced by setup_pes().