PMM Stack

A generic free stack page allocator. More...

Data Structures
struct	page_buffer_t
	Structure for a page buffer in the PMM stack. More...
struct	pmm_stack_t
	PMM stack structure for managing higher physical memory. More...

Macros
#define	PMM_BUFFER_MAX   ((PAGE_SIZE - sizeof(page_buffer_t)) / sizeof(void*))
	The maximum number of pages that can be stored in a page_buffer_t.

Functions
void	pmm_stack_init (pmm_stack_t *stack)
	Initializes a PMM stack.
void *	pmm_stack_alloc (pmm_stack_t *stack)
	Allocates a single page from the stack.
void	pmm_stack_free (pmm_stack_t *stack, void *address)
	Frees a single page, returning it to the stack.

Detailed Description

A generic free stack page allocator.

The PMM stack provides a fast, O(1) allocator for single pages. It uses freed pages to store metadata about other free pages, forming a stack of page buffers.

Macro Definition Documentation

PMM_BUFFER_MAX

#define PMM_BUFFER_MAX   ((PAGE_SIZE - sizeof(page_buffer_t)) / sizeof(void*))

The maximum number of pages that can be stored in a page_buffer_t.

Definition at line 36 of file pmm_stack.h.

Function Documentation

pmm_stack_alloc()

void * pmm_stack_alloc

(

pmm_stack_t *

stack

)

Allocates a single page from the stack.

Parameters

stack

The stack to allocate from.

Returns

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

Definition at line 12 of file pmm_stack.c.

References address, pmm_stack_t::free, pmm_stack_t::index, pmm_stack_t::last, NULL, page_buffer_t::pages, PMM_BUFFER_MAX, page_buffer_t::prev, and stack.

Referenced by pmm_alloc(), and pmm_alloc_pages().

pmm_stack_free()

void pmm_stack_free	(	pmm_stack_t *	stack,
		void *	address
	)

Frees a single page, returning it to the stack.

Parameters

stack	The stack to free to.
address	The address of the page to free.

Definition at line 36 of file pmm_stack.c.

References address, pmm_stack_t::free, pmm_stack_t::index, pmm_stack_t::last, next, NULL, PAGE_SIZE, page_buffer_t::pages, PMM_BUFFER_MAX, page_buffer_t::prev, ROUND_DOWN, and stack.

Referenced by pmm_alloc_pages(), pmm_free_pages_unlocked(), and pmm_free_unlocked().

pmm_stack_init()

void pmm_stack_init

(

pmm_stack_t *

stack

)

Initializes a PMM stack.

Parameters

stack

The stack to initialize.

Definition at line 5 of file pmm_stack.c.

References pmm_stack_t::free, pmm_stack_t::index, pmm_stack_t::last, NULL, and stack.

Referenced by pmm_init().