alloc.cc File Reference

#include "utils/alloc.h"
#include "utils/alloc_buddy.h"
#include "utils/math.h"
#include "utils/string.h"
#include "machine/cache.h"
#include "debug/assert.h"

Include dependency graph for alloc.cc:

Functions
static void *	reserve (void *start, size_t size)
	Memory reservation function for allocator Will return memory from a statically allocated char array in bss.
void *	malloc (size_t size)
	Allocate a memory block The memory is not initialized.
void	free (void *ptr)
	Free an allocated memory block.
void *	realloc (void *ptr, size_t size)
	Change the size of an allocated memory block The contents will be unchanged in the range from the start of the region up to the minimum of the old and new sizes. If the new size is larger than the old size, the added memory will not be initialized.
void *	calloc (size_t nmemb, size_t size)
	Allocate memory for an array of elements The memory is set to zero.

Constants
cache_aligned bool	in_use = false
	Concurrent access is not allowed Use assertions to detect bugs.
static const size_t	ALLOC_LOG2 = 24
	Reserved memory size as power of 2.
static const size_t	mem_size = 1 << ALLOC_LOG2
	(Resulting) reserved memory size
static char	mem [mem_size]
	Reserved memory (will be statically allocated in bss)
static Allocator::Buddy< 4, ALLOC_LOG2, sizeof(size_t) *2, reserve >	allocator
	Instantiate a Buddy allocator using the custom reserve function.

Function Documentation

reserve()

static void * reserve ( void *  start, size_t  size  )

static

Memory reservation function for allocator Will return memory from a statically allocated char array in bss.

Parameters

start	Start address for requested memory, if nullptr it will use the pointer to the char array instead
size	Requested memory size

Returns

If the requested size after the start address is within the allocated char array, the start address is returned – nullptr otherwise.

malloc()

void * malloc

(

size_t

size

)

Allocate a memory block The memory is not initialized.

Parameters

size	Requested size of memory in bytes.

Returns

Pointer to memory or nullptr on error (no memory available) or if size was zero.

Optional:

Implement method

free()

void free

(

void *

ptr

)

Free an allocated memory block.

Parameters

ptr	Pointer to an previously allocated memory block.

Optional:

Implement method

realloc()

void * realloc	(	void *	ptr,
		size_t	size
	)

Change the size of an allocated memory block The contents will be unchanged in the range from the start of the region up to the minimum of the old and new sizes. If the new size is larger than the old size, the added memory will not be initialized.

Parameters

ptr	Pointer to an previously allocated memory block. If nullptr, then the call is equivalent to malloc().
size	New size of the memory block. If equal to zero, then the call is equivalent to free

Returns

Pointer to new memory block or nullptr on error

Optional:

Implement method

calloc()

void * calloc	(	size_t	nmemb,
		size_t	size
	)

Allocate memory for an array of elements The memory is set to zero.

Parameters

nmemb	Number of elements
size	Size of an element in bytes

Returns

pointer to the allocated memory or nullptr if the request fails

Optional:

Implement method

Variable Documentation

in_use

cache_aligned bool in_use = false

Concurrent access is not allowed Use assertions to detect bugs.

ALLOC_LOG2

const size_t ALLOC_LOG2 = 24

static

Reserved memory size as power of 2.

mem_size

const size_t mem_size = 1 << ALLOC_LOG2

static

(Resulting) reserved memory size

mem

char mem[mem_size]

static

Reserved memory (will be statically allocated in bss)

allocator

Allocator::Buddy<4, ALLOC_LOG2, sizeof(size_t) * 2, reserve> allocator

static

Instantiate a Buddy allocator using the custom reserve function.