#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, Permissions maximumPerms=Read\|Write\|Exec, const SharedPointer< MappingAttachment > &attachment=SharedPointer< MappingAttachment >(), const FileMappingOrigin &origin={}, bool executableUse=false)

virtual MemoryMappedObject *	clone () override

virtual MemoryMappedObject *	split (uintptr_t at) override

MemoryMappedObject *	stageSlice (uintptr_t source, size_t sourceLength, uintptr_t destination, size_t destinationLength) override

void	releaseDetachedPage (uintptr_t oldAddress, const VirtualAddressSpace::DetachedPage &page) override

void	discardRange (VirtualAddressSpace &space, uintptr_t base, size_t length) override

File *	backingFile () const override

bool	backingRangeValid (uintptr_t source, size_t length) const override

bool	resident (VirtualAddressSpace &space, uintptr_t address, FileResidencyAccess access, void *credentials) override

virtual bool	remove (size_t length) override

virtual void	setPermissions (MemoryMappedObject::Permissions perms) override

virtual bool	sync (uintptr_t at, bool async) override

bool	syncRange (uintptr_t at, size_t length, bool async) override

virtual void	invalidate (uintptr_t at) override

virtual bool	sharedBacking (uintptr_t at, uintptr_t &identity, size_t &offset) const override

virtual bool	usesBacking (uintptr_t identity) const override

virtual bool	beyondBackingEnd (uintptr_t at) const override

virtual void	discardFilePages (VirtualAddressSpace &space, size_t end) override

virtual bool	preparePermissions (uintptr_t base, size_t length, Permissions perms) override

virtual void	unmap () override

virtual bool	trap (VirtualAddressSpace &space, uintptr_t address, bool bWrite, PopulationStatus *population=nullptr) override

virtual bool	compact () override

Public Member Functions inherited from MemoryMappedObject
	MemoryMappedObject (uintptr_t address, bool bCopyOnWrite, size_t length, Permissions perms, Permissions maximumPerms=Read\|Write\|Exec)

void	setMappingOwnership (bool ownsMappings)

virtual PopulationStatus	prepareResidentAccess (VirtualAddressSpace &space, uintptr_t address)

PopulationStatus	populatePage (VirtualAddressSpace &space, uintptr_t address)

MemoryLockMode	lockMode () const

virtual bool	supportsPageOut (VirtualAddressSpace &space, uintptr_t address)

virtual SwapStatus	pageOutAt (VirtualAddressSpace &space, uintptr_t address, bool &released)

virtual bool	reclaimAnonymousPage (VirtualAddressSpace &space)

virtual SwapStatus	restoreSwapPages (VirtualAddressSpace &space)

bool	matches (uintptr_t address)

uintptr_t	address () const

size_t	length () const

Permissions	permissions () const

Permissions	maximumPermissions () const

Private Member Functions
void	unmapUnlocked ()

physical_uintptr_t	getBackingPage (size_t fileOffset, size_t mappingBytes)

void	releaseDetachedPageUnlocked (uintptr_t oldAddress, const VirtualAddressSpace::DetachedPage &page)

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

size_t	m_ReadAheadEnd = ~size_t{0}

size_t	m_ReadAheadPages = 4

Tree< uintptr_t, physical_uintptr_t >	m_Mappings

FileMappingOrigin	m_Origin

Mutex	m_Lock

bool	m_bVfsLease

bool	m_ExecutableUse

bool	m_SharedWriteUse

bool	m_UseAdmitted

Friends
class	MemoryMapManager

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

Permissions	m_MaximumPermissions

SharedPointer< MappingAttachment >	m_Attachment

Process *	m_OwnerProcess

bool	m_OwnsMappings

MemoryLockMode	m_LockMode

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 442 of file MemoryMappedFile.h.

Constructor & Destructor Documentation

◆ MemoryMappedFile()

MemoryMappedFile::MemoryMappedFile	(	uintptr_t	address,
		size_t	length,
		size_t	offset,
		File *	backing,
		bool	bCopyOnWrite,
		MemoryMappedObject::Permissions	perms,
		MemoryMappedObject::Permissions	maximumPerms = `Read \| Write \| Exec`,
		const SharedPointer< MappingAttachment > &	attachment = `SharedPointer<MappingAttachment>()`,
		const FileMappingOrigin &	origin = `{}`,
		bool	executableUse = `false`
	)

Definition at line 176 of file MemoryMappedFile.cc.

◆ ~MemoryMappedFile()

MemoryMappedFile::~MemoryMappedFile ( )

overridevirtual

Definition at line 195 of file MemoryMappedFile.cc.

Member Function Documentation

◆ backingFile()

File * MemoryMappedFile::backingFile ( ) const

inlineoverridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 461 of file MemoryMappedFile.h.

◆ backingRangeValid()

bool MemoryMappedFile::backingRangeValid	(	uintptr_t	source,
		size_t	length
	)		const

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 13 of file MemoryMappedFile-remap.cc.

◆ beyondBackingEnd()

bool MemoryMappedFile::beyondBackingEnd ( uintptr_t at ) const

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 382 of file MemoryMappedFile.cc.

◆ clearMappings()

void MemoryMappedFile::clearMappings ( )

private

Clear all mappings.

Definition at line 778 of file MemoryMappedFile.cc.

References Tree< K, E >::clear(), and m_Mappings.

◆ clone()

MemoryMappedObject * MemoryMappedFile::clone ( )

overridevirtual

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 208 of file MemoryMappedFile.cc.

References assert, Tree< K, E >::begin(), Tree< K, E >::end(), File::getPhysicalPage(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Mappings, m_Offset, m_pBacking, and MemoryMappedObject::m_Permissions.

◆ compact()

bool MemoryMappedFile::compact ( )

overridevirtual

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 688 of file MemoryMappedFile.cc.

References MemoryMappedObject::address(), VirtualAddressSpace::detachMapping(), getMapping(), PhysicalMemoryManager::getPageSize(), ProcessorBase::information(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Offset, m_pBacking, Semaphore::release(), File::returnPhysicalPage(), File::sync(), Semaphore::tryAcquire(), File::tryBeginMappingRelease(), and untrackMapping().

◆ discardFilePages()

void MemoryMappedFile::discardFilePages	(	VirtualAddressSpace &	space,
		size_t	end
	)

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 390 of file MemoryMappedFile.cc.

◆ discardRange()

void MemoryMappedFile::discardRange	(	VirtualAddressSpace &	space,
		uintptr_t	base,
		size_t	length
	)

overridevirtual

Implements MemoryMappedObject.

Definition at line 57 of file MemoryMappedFile-advice.cc.

◆ getBackingPage()

physical_uintptr_t MemoryMappedFile::getBackingPage	(	size_t	fileOffset,
		size_t	mappingBytes
	)

private

Definition at line 423 of file MemoryMappedFile.cc.

◆ getMapping()

physical_uintptr_t MemoryMappedFile::getMapping ( uintptr_t addr )

private

Get a specific mapping.

Definition at line 770 of file MemoryMappedFile.cc.

References Tree< K, E >::lookup(), and m_Mappings.

Referenced by compact(), remove(), split(), sync(), and syncRange().

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◆ getMappingCount()

size_t MemoryMappedFile::getMappingCount ( )

private

Get the number of mappings we currently have.

Definition at line 774 of file MemoryMappedFile.cc.

References Tree< K, E >::count(), and m_Mappings.

◆ invalidate()

void MemoryMappedFile::invalidate ( uintptr_t at )

overridevirtual

Invalidate cached state without discarding private modifications.

Reimplemented from MemoryMappedObject.

Definition at line 517 of file MemoryMappedFile.cc.

◆ preparePermissions()

bool MemoryMappedFile::preparePermissions	(	uintptr_t	base,
		size_t	length,
		Permissions	perms
	)

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 354 of file MemoryMappedFile.cc.

◆ releaseDetachedPage()

void MemoryMappedFile::releaseDetachedPage	(	uintptr_t	oldAddress,
		const VirtualAddressSpace::DetachedPage &	page
	)

overridevirtual

Implements MemoryMappedObject.

Definition at line 51 of file MemoryMappedFile-advice.cc.

◆ releaseDetachedPageUnlocked()

void MemoryMappedFile::releaseDetachedPageUnlocked	(	uintptr_t	oldAddress,
		const VirtualAddressSpace::DetachedPage &	page
	)

private

Definition at line 35 of file MemoryMappedFile-advice.cc.

◆ remove()

bool MemoryMappedFile::remove ( size_t length )

overridevirtual

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 273 of file MemoryMappedFile.cc.

References PhysicalMemoryManager::freePage(), getMapping(), VirtualAddressSpace::getMapping(), PhysicalMemoryManager::getPageSize(), ProcessorBase::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), MemoryMappedObject::length(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Offset, m_pBacking, File::returnPhysicalPage(), File::syncAndReturnPhysicalPage(), VirtualAddressSpace::unmap(), and untrackMapping().

◆ resident()

bool MemoryMappedFile::resident	(	VirtualAddressSpace &	space,
		uintptr_t	address,
		FileResidencyAccess	access,
		void *	credentials
	)

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 17 of file MemoryMappedFile-advice.cc.

◆ setPermissions()

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

overridevirtual

Sets permissions on this object.

Resident pages retain their contents and ownership.

Implements MemoryMappedObject.

Definition at line 326 of file MemoryMappedFile.cc.

References File::acquireMappingUse(), MemoryMappedObject::address(), assert, Tree< K, E >::begin(), Tree< K, E >::end(), VirtualAddressSpace::getMapping(), ProcessorBase::information(), VirtualAddressSpace::isMapped(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, m_Lock, m_Mappings, m_Offset, m_pBacking, MemoryMappedObject::m_Permissions, File::markPageExternallyWritable(), VirtualAddressSpace::setFlags(), and VirtualAddressSpace::Write.

◆ sharedBacking()

bool MemoryMappedFile::sharedBacking	(	uintptr_t	at,
		uintptr_t &	identity,
		size_t &	offset
	)		const

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 369 of file MemoryMappedFile.cc.

◆ split()

MemoryMappedObject * MemoryMappedFile::split ( uintptr_t at )

overridevirtual

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 229 of file MemoryMappedFile.cc.

References assert, Tree< K, E >::contains(), getMapping(), PhysicalMemoryManager::getPageSize(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Mappings, m_Offset, m_pBacking, MemoryMappedObject::m_Permissions, trackMapping(), and untrackMapping().

◆ stageSlice()

MemoryMappedObject * MemoryMappedFile::stageSlice	(	uintptr_t	source,
		size_t	sourceLength,
		uintptr_t	destination,
		size_t	destinationLength
	)

overridevirtual

Prepared slices transfer existing page ownership only after publication.

Implements MemoryMappedObject.

Definition at line 18 of file MemoryMappedFile-remap.cc.

References Tree< K, E >::begin(), Tree< K, E >::count(), Tree< K, E >::end(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Mappings, m_Offset, m_pBacking, and MemoryMappedObject::m_Permissions.

◆ sync()

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

overridevirtual

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

Reimplemented from MemoryMappedObject.

Definition at line 507 of file MemoryMappedFile.cc.

References getMapping(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Offset, m_pBacking, and File::sync().

◆ syncRange()

bool MemoryMappedFile::syncRange	(	uintptr_t	at,
		size_t	length,
		bool	async
	)

overridevirtual

Synchronise a contiguous mapping range without imposing a barrier per page.

Reimplemented from MemoryMappedObject.

Definition at line 473 of file MemoryMappedFile.cc.

References MemoryMappedObject::address(), getMapping(), PhysicalMemoryManager::getPageSize(), MemoryMappedObject::length(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Offset, m_pBacking, File::sync(), and File::syncPages().

◆ trackMapping()

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

private

Track a new mapping.

Definition at line 762 of file MemoryMappedFile.cc.

References Tree< K, E >::insert(), and m_Mappings.

Referenced by split().

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◆ trap()

bool MemoryMappedFile::trap	(	VirtualAddressSpace &	space,
		uintptr_t	address,
		bool	bWrite,
		PopulationStatus *	population = `nullptr`
	)

overridevirtual

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.

Implements MemoryMappedObject.

Definition at line 529 of file MemoryMappedFile.cc.

References MemoryMappedObject::address(), PhysicalMemoryManager::allocatePage(), VirtualAddressSpace::Borrowed, EMIT_IF, VirtualAddressSpace::Execute, PhysicalMemoryManager::freePage(), PhysicalMemoryManager::getPageSize(), ProcessorBase::information(), PhysicalMemoryManager::instance(), VirtualAddressSpace::isMapped(), MemoryMappedObject::m_Address, MemoryMappedObject::m_bCopyOnWrite, MemoryMappedObject::m_Length, m_Lock, m_Mappings, m_Offset, m_pBacking, MemoryMappedObject::m_Permissions, VirtualAddressSpace::map(), File::markPageExternallyWritable(), File::prepareSharedMapping(), File::read(), File::returnPhysicalPage(), VirtualAddressSpace::Shared, Tree< K, E >::tryInsert(), VirtualAddressSpace::unmap(), untrackMapping(), and VirtualAddressSpace::Write.

◆ unmap()

void MemoryMappedFile::unmap ( )

overridevirtual

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 522 of file MemoryMappedFile.cc.

References m_Lock.

◆ unmapUnlocked()

void MemoryMappedFile::unmapUnlocked ( )

private

Definition at line 726 of file MemoryMappedFile.cc.

◆ untrackMapping()

void MemoryMappedFile::untrackMapping ( uintptr_t addr )

private

Stop tracking a mapping.

Definition at line 766 of file MemoryMappedFile.cc.

References m_Mappings, and Tree< K, E >::remove().

Referenced by compact(), remove(), split(), and trap().

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◆ usesBacking()

bool MemoryMappedFile::usesBacking ( uintptr_t identity ) const

overridevirtual

Reimplemented from MemoryMappedObject.

Definition at line 378 of file MemoryMappedFile.cc.

Friends And Related Symbol Documentation

◆ MemoryMapManager

friend class MemoryMapManager

friend

Definition at line 443 of file MemoryMappedFile.h.

Member Data Documentation

◆ m_bVfsLease

bool MemoryMappedFile::m_bVfsLease

private

Whether this mapping retained an established VFS File owner.

Definition at line 547 of file MemoryMappedFile.h.

◆ m_ExecutableUse

bool MemoryMappedFile::m_ExecutableUse

private

Definition at line 548 of file MemoryMappedFile.h.

◆ m_Lock

Mutex MemoryMappedFile::m_Lock

private

Lock for anything to do with the memory mapped file.

Backing-file reads and synchronisation may block, so this must be a sleeping lock rather than a Spinlock.

Definition at line 544 of file MemoryMappedFile.h.

Referenced by clone(), compact(), remove(), setPermissions(), split(), sync(), syncRange(), trap(), and unmap().

◆ m_Mappings

Tree<uintptr_t, physical_uintptr_t> MemoryMappedFile::m_Mappings

private

List of existing mappings.

Definition at line 535 of file MemoryMappedFile.h.

Referenced by clearMappings(), clone(), getMapping(), getMappingCount(), setPermissions(), split(), stageSlice(), trackMapping(), trap(), and untrackMapping().

◆ m_Offset

size_t MemoryMappedFile::m_Offset

private

Offset within the file that this mapping begins at.

Definition at line 529 of file MemoryMappedFile.h.

Referenced by clone(), compact(), remove(), setPermissions(), split(), stageSlice(), sync(), syncRange(), and trap().

◆ m_Origin

FileMappingOrigin MemoryMappedFile::m_Origin

private

Definition at line 536 of file MemoryMappedFile.h.

◆ m_pBacking

File* MemoryMappedFile::m_pBacking

private

Backing file.

Definition at line 526 of file MemoryMappedFile.h.

Referenced by clone(), compact(), remove(), setPermissions(), split(), stageSlice(), sync(), syncRange(), and trap().

◆ m_ReadAheadEnd

size_t MemoryMappedFile::m_ReadAheadEnd = ~size_t{0}

private

Definition at line 531 of file MemoryMappedFile.h.

◆ m_ReadAheadPages

size_t MemoryMappedFile::m_ReadAheadPages = 4

private

Definition at line 532 of file MemoryMappedFile.h.

◆ m_SharedWriteUse

bool MemoryMappedFile::m_SharedWriteUse

private

Definition at line 549 of file MemoryMappedFile.h.

◆ m_UseAdmitted

bool MemoryMappedFile::m_UseAdmitted

private

Definition at line 550 of file MemoryMappedFile.h.

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

Public Member Functions

Private Member Functions

Private Attributes

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MemoryMappedFile()

◆ ~MemoryMappedFile()

Member Function Documentation

◆ backingFile()

◆ backingRangeValid()

◆ beyondBackingEnd()

◆ clearMappings()

◆ clone()

◆ compact()

◆ discardFilePages()

◆ discardRange()

◆ getBackingPage()

◆ getMapping()

◆ getMappingCount()

◆ invalidate()

◆ preparePermissions()

◆ releaseDetachedPage()

◆ releaseDetachedPageUnlocked()

◆ remove()

◆ resident()

◆ setPermissions()

◆ sharedBacking()

◆ split()

◆ stageSlice()

◆ sync()

◆ syncRange()

◆ trackMapping()

◆ trap()

◆ unmap()

◆ unmapUnlocked()

◆ untrackMapping()

◆ usesBacking()

Friends And Related Symbol Documentation

◆ MemoryMapManager

Member Data Documentation

◆ m_bVfsLease

◆ m_ExecutableUse

◆ m_Lock

◆ m_Mappings

◆ m_Offset

◆ m_Origin

◆ m_pBacking

◆ m_ReadAheadEnd

◆ m_ReadAheadPages

◆ m_SharedWriteUse

◆ m_UseAdmitted