PMM Bitmap

A generic bitmap page allocator. More...

Data Structures
struct	pmm_bitmap_t
	Represents a bitmap allocator's state. More...

Functions
void	pmm_bitmap_init (pmm_bitmap_t *bitmap, void *buffer, uint64_t size, uintptr_t maxAddr)
	Initializes a PMM bitmap.
void *	pmm_bitmap_alloc (pmm_bitmap_t *bitmap, uint64_t count, uintptr_t maxAddr, uint64_t alignment)
	Allocates a contiguous region of pages from the bitmap.
void	pmm_bitmap_free (pmm_bitmap_t *bitmap, void *address, uint64_t count)
	Frees a region of pages, returning them to the bitmap.

Detailed Description

A generic bitmap page allocator.

The PMM bitmap provides a flexible allocator for more specific allocations, for example it can handle contiguous pages, specific alignments and allocating below some specified address. This flexibility comes at the cost of performance, so the bitmap should only be used when necessary.

Function Documentation

pmm_bitmap_alloc()

void * pmm_bitmap_alloc	(	pmm_bitmap_t *	bitmap,
		uint64_t	count,
		uintptr_t	maxAddr,
		uint64_t	alignment
	)

Allocates a contiguous region of pages from the bitmap.

Parameters

bitmap	The bitmap to allocate from.
count	The number of pages to allocate.
maxAddr	The maximum address for the allocation.
alignment	The required alignment for the allocation.

Returns

On success, a pointer to the allocated region. On failure NULL and errno is set.

Definition at line 16 of file pmm_bitmap.c.

References pmm_bitmap_t::bitmap, bitmap, bitmap_find_clear_region_and_set(), count, pmm_bitmap_t::free, bitmap_t::length, MAX, pmm_bitmap_t::maxAddr, MIN, NULL, PAGE_SIZE, PML_HIGHER_HALF_START, and ROUND_UP.

Referenced by pmm_alloc_bitmap().

pmm_bitmap_free()

void pmm_bitmap_free	(	pmm_bitmap_t *	bitmap,
		void *	address,
		uint64_t	count
	)

Frees a region of pages, returning them to the bitmap.

Parameters

bitmap	The bitmap to free to.
address	The address of the region to free.
count	The number of pages to free.

Definition at line 32 of file pmm_bitmap.c.

References address, assert, pmm_bitmap_t::bitmap, bitmap, bitmap_clear_range(), count, pmm_bitmap_t::free, PAGE_SIZE, PML_HIGHER_TO_LOWER, and ROUND_DOWN.

Referenced by pmm_free_pages_unlocked(), and pmm_free_unlocked().

pmm_bitmap_init()

void pmm_bitmap_init	(	pmm_bitmap_t *	bitmap,
		void *	buffer,
		uint64_t	size,
		uintptr_t	maxAddr
	)

Initializes a PMM bitmap.

Parameters

bitmap	The bitmap to initialize.
buffer	The buffer to use for the bitmap data.
size	The number of pages to manage.
maxAddr	The maximum address to manage.

Definition at line 7 of file pmm_bitmap.c.

References assert, pmm_bitmap_t::bitmap, bitmap, bitmap_init(), buffer, pmm_bitmap_t::free, pmm_bitmap_t::maxAddr, PAGE_SIZE, and pmm_bitmap_t::total.

Referenced by pmm_init().