Virtual_memory Class Reference

Virtual_memory is the allocator/deallocator for virtual memory. More...

#include <virtmem.h>

Collaboration diagram for Virtual_memory:

[legend]List of all members.

Public Member Functions
void	init (unsigned &last_available_address)
void *	alloc (Size request_size)
void *	resize (void *memory, Size new_size)
void	free (void *memory)
void	enable ()
bool	is_enabled ()
bool	manages (void *virtual_page)
void	print ()
Static Public Member Functions
Virtual_memory *	create (unsigned &last_available_address, bool map_memory=false)
Public Attributes
Page_allocator	virtual_pages
Protected Attributes
Slab_allocator	allocators [PAGE_ALIGNMENT]
bool	enabled
Static Protected Attributes
const unsigned	MAX_PAGE_SPAN_ALIGNMENT = 16

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Detailed Description

Virtual_memory is the allocator/deallocator for virtual memory.

The original slab allocator code was generously contributed by Lee Salzman. There is one slab allocator for each power-of-two object size up to PAGE_SIZE.

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Member Function Documentation

void * Virtual_memory::alloc (  Size  request_size  )

Allocate some virtual memory of the given size in bytes and return it.

Virtual_memory * Virtual_memory::create (  unsigned &  last_available_address, bool  map_memory = false )  [static]

Create a Virtual_memory allocator object below the given address and return a pointer to the new object. If map_memory is true then this new allocator will be mapped into physical memory, and init() should be be called on it before use. If map_memory is false, then this allocator will be brought in from disk and then immediately enabled.

void Virtual_memory::enable (   )  [inline]

Enable the virtual memory and allow allocation.

void Virtual_memory::free (  void *  memory  )

Free some virtual memory previously allocated by alloc().

void Virtual_memory::init (  unsigned &  last_available_address  )

Initialize the virtual memory allocator.

bool Virtual_memory::is_enabled (   )  [inline]

Return whether virtual memory is active.

bool Virtual_memory::manages (  void *  virtual_page  )  [inline]

Return whether this virtual memory allocator manages the given page.

void Virtual_memory::print (   )

Print basic information on the virtual memory allocator.

void * Virtual_memory::resize (  void *  memory, Size  new_size )

Resize some existing allocated memory to a new size.

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Member Data Documentation

Slab_allocator Virtual_memory::allocators[PAGE_ALIGNMENT] [protected]

managed slab allocators

bool Virtual_memory::enabled [protected]

whether virtual memory is active

const unsigned Virtual_memory::MAX_PAGE_SPAN_ALIGNMENT = 16 [static, protected]

largest possible page span is PAGE_SIZE * 2^MAX_PAGE_SPAN_ALIGNMENT bytes

Page_allocator Virtual_memory::virtual_pages

page allocator for virtual memory

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The documentation for this class was generated from the following files:

• virtmem.h
• virtmem.cc

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Torsion Operating System, Copyright (C) 2000-2004 Dan Helfman