#include <MemoryMappedFile.h>

Inheritance diagram for MemoryMappedFile:

Collaboration diagram for MemoryMappedFile:

Public Member Functions
	MemoryMappedFile (uintptr_t address, size_t length, size_t offset, File *backing, bool bCopyOnWrite, Permissions perms)

virtual MemoryMappedObject *	clone ()

virtual MemoryMappedObject *	split (uintptr_t at)

virtual bool	remove (size_t length)

virtual void	setPermissions (MemoryMappedObject::Permissions perms)

virtual void	sync (uintptr_t at, bool async)

virtual void	invalidate (uintptr_t at)

virtual void	unmap ()

virtual bool	trap (uintptr_t address, bool bWrite)

virtual bool	compact ()

Public Member Functions inherited from MemoryMappedObject
	MemoryMappedObject (uintptr_t address, bool bCopyOnWrite, size_t length, Permissions perms)

bool	matches (uintptr_t address)

uintptr_t	address () const

size_t	length () const

Private Member Functions
void	unmapUnlocked ()

void	trackMapping (uintptr_t, physical_uintptr_t)

void	untrackMapping (uintptr_t)

physical_uintptr_t	getMapping (uintptr_t)

size_t	getMappingCount ()

void	clearMappings ()

Private Attributes
File *	m_pBacking

size_t	m_Offset

Tree< uintptr_t, physical_uintptr_t >	m_Mappings

Spinlock	m_Lock

Additional Inherited Members
Public Types inherited from MemoryMappedObject
typedef int	Permissions

Static Public Attributes inherited from MemoryMappedObject
static const int	None = 0x0

static const int	Read = 0x1

static const int	Write = 0x2

static const int	Exec = 0x4

Protected Attributes inherited from MemoryMappedObject
bool	m_bCopyOnWrite

uintptr_t	m_Address

size_t	m_Length

Permissions	m_Permissions

Detailed Description

File map object.

File maps actually provide a backing file for a memory region. These are used for loading binaries or for opening files for reading without the overhead of read/write syscalls (assuming the syscall is more expensive than a page fault).

Definition at line 323 of file MemoryMappedFile.h.

Member Function Documentation

void MemoryMappedFile::clearMappings ( )

private

Clear all mappings.

Definition at line 951 of file MemoryMappedFile.cc.

MemoryMappedObject * MemoryMappedFile::clone ( )

virtual

Clones the existing metadata of this object into another.

Returns a MemoryMappedObject that exactly matches this one, but which can be used for reference in a new address space. Used for address space clones.

Note that mappings are automatically cloned - only clone metadata in this method.

Implements MemoryMappedObject.

Definition at line 359 of file MemoryMappedFile.cc.

References m_Mappings.

bool MemoryMappedFile::compact ( )

virtual

Syncs back all dirty pages to their respective backing store.

Compacting begins by doing a pass to find any pages that can be synced and then unpinned, allowing a future Cache eviction. Should that pass successfully free memory, the compact will be considered successful.

If that pass is not successful, read-only pages are evicted. At this stage, this is done in a linear fashion; there is no LRU or other type of algorithm at play.

Todo:: Improve this.

Returns: true if at least one page was released, false otherwise.

Reimplemented from MemoryMappedObject.

Definition at line 807 of file MemoryMappedFile.cc.

References PhysicalMemoryManager::freePage(), VirtualAddressSpace::getMapping(), PhysicalMemoryManager::getPageSize(), Processor::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), NOTICE, VirtualAddressSpace::unmap(), and VirtualAddressSpace::Write.

physical_uintptr_t MemoryMappedFile::getMapping ( uintptr_t addr )

private

Get a specific mapping.

Definition at line 941 of file MemoryMappedFile.cc.

size_t MemoryMappedFile::getMappingCount ( )

private

Get the number of mappings we currently have.

Definition at line 946 of file MemoryMappedFile.cc.

void MemoryMappedFile::invalidate ( uintptr_t at )

virtual

If the given page is dirty (and this is a CoW mapping), restore it to the file's actual content.

Reimplemented from MemoryMappedObject.

Definition at line 616 of file MemoryMappedFile.cc.

References ERROR, VirtualAddressSpace::Execute, PhysicalMemoryManager::freePage(), Processor::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), VirtualAddressSpace::map(), VirtualAddressSpace::Shared, and VirtualAddressSpace::unmap().

bool MemoryMappedFile::remove ( size_t length )

virtual

Removes pages from the start of this MemoryMappedObject.

To remove pages from the middle or end of a MemoryMappedObject, use split() and then remove()/unmap() on the returned object).

Returns: true if the remove() has effectively removed the entire MemoryMappedObject, false otherwise.

Implements MemoryMappedObject.

Definition at line 423 of file MemoryMappedFile.cc.

References PhysicalMemoryManager::freePage(), VirtualAddressSpace::getMapping(), PhysicalMemoryManager::getPageSize(), Processor::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), VirtualAddressSpace::unmap(), and VirtualAddressSpace::Write.

void MemoryMappedFile::setPermissions ( MemoryMappedObject::Permissions perms )

virtual

Sets permissions on this object.

This may trigger unmaps if the new permissions.

Implements MemoryMappedObject.

Definition at line 483 of file MemoryMappedFile.cc.

References Spinlock::acquire(), ERROR, VirtualAddressSpace::Execute, VirtualAddressSpace::getMapping(), File::getName(), PhysicalMemoryManager::getPageSize(), File::getPhysicalPage(), Processor::information(), VirtualAddressSpace::isMapped(), File::read(), Spinlock::release(), VirtualAddressSpace::setFlags(), VirtualAddressSpace::Shared, and VirtualAddressSpace::Write.

MemoryMappedObject * MemoryMappedFile::split ( uintptr_t at )

virtual

Splits the metadata of this object at the given address and creates a new MemoryMappedObject that begins at the page of the split.

Implements MemoryMappedObject.

Definition at line 379 of file MemoryMappedFile.cc.

References ERROR, PhysicalMemoryManager::getPageSize(), and trackMapping().

void MemoryMappedFile::sync	(	uintptr_t	at,
		bool	async
	)

virtual

Sync back the given page to a backing store, if one exists.

Reimplemented from MemoryMappedObject.

Definition at line 579 of file MemoryMappedFile.cc.

References ERROR, VirtualAddressSpace::getMapping(), Processor::information(), VirtualAddressSpace::isMapped(), and VirtualAddressSpace::Write.

void MemoryMappedFile::trackMapping	(	uintptr_t	addr,
		physical_uintptr_t	phys
	)

private

Track a new mapping.

Definition at line 931 of file MemoryMappedFile.cc.

Referenced by split().

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bool MemoryMappedFile::trap	(	uintptr_t	address,
		bool	bWrite
	)

virtual

Trap entry

Implement this in your implementation to actually perform the mapping of memory into the address space.

Returns: true if the trap was successful, false otherwise.

Todo:: how to manage this with potentially more traps taking place?

Implements MemoryMappedObject.

Definition at line 683 of file MemoryMappedFile.cc.

References PhysicalMemoryManager::allocatePage(), DEBUG_LOG, ERROR, VirtualAddressSpace::Execute, PhysicalMemoryManager::getPageSize(), Processor::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), VirtualAddressSpace::map(), NOTICE, VirtualAddressSpace::Shared, VirtualAddressSpace::unmap(), and VirtualAddressSpace::Write.

void MemoryMappedFile::unmap ( )

virtual

Unmaps existing mappings in this object from the address space.

Implementations are expected to track these as necessary for the implementation.

Implements MemoryMappedObject.

Definition at line 676 of file MemoryMappedFile.cc.

void MemoryMappedFile::untrackMapping ( uintptr_t addr )

private

Stop tracking a mapping.

Definition at line 936 of file MemoryMappedFile.cc.

Member Data Documentation

Spinlock MemoryMappedFile::m_Lock

private

Lock for anything to do with the memory mapped file.

Definition at line 390 of file MemoryMappedFile.h.

Tree<uintptr_t, physical_uintptr_t> MemoryMappedFile::m_Mappings

private

List of existing mappings.

Definition at line 387 of file MemoryMappedFile.h.

Referenced by clone().

size_t MemoryMappedFile::m_Offset

private

Offset within the file that this mapping begins at.

Definition at line 384 of file MemoryMappedFile.h.

File* MemoryMappedFile::m_pBacking

private

Backing file.

Definition at line 381 of file MemoryMappedFile.h.

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

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

Member Data Documentation