Specialization for accessing a copy-on-write disk image layer. More...

#include <disk_image.hh>

Inheritance diagram for gem5::CowDiskImage:

Classes
struct	Sector

Public Types
typedef CowDiskImageParams	Params

Public Types inherited from gem5::DiskImage
typedef DiskImageParams	Params

Public Types inherited from gem5::SimObject
typedef SimObjectParams	Params

Public Member Functions
	CowDiskImage (const Params &p)

	~CowDiskImage ()

void	notifyFork () override
	Notify a child process of a fork.

void	initSectorTable (int hash_size)

bool	open (const std::string &file)

void	save () const

void	save (const std::string &file) const

void	writeback ()

void	serialize (CheckpointOut &cp) const override
	Serialize an object.

void	unserialize (CheckpointIn &cp) override
	Unserialize an object.

std::streampos	size () const override

std::streampos	read (uint8_t *data, std::streampos offset) const override

std::streampos	write (const uint8_t *data, std::streampos offset) override

Public Member Functions inherited from gem5::DiskImage
	DiskImage (const Params &p)

virtual	~DiskImage ()

Public Member Functions inherited from gem5::SimObject
const Params &	params () const

	SimObject (const Params &p)

virtual	~SimObject ()

virtual void	init ()
	init() is called after all C++ SimObjects have been created and all ports are connected.

virtual void	loadState (CheckpointIn &cp)
	loadState() is called on each SimObject when restoring from a checkpoint.

virtual void	initState ()
	initState() is called on each SimObject when not restoring from a checkpoint.

virtual void	regProbePoints ()
	Register probe points for this object.

virtual void	regProbeListeners ()
	Register probe listeners for this object.

ProbeManager *	getProbeManager ()
	Get the probe manager for this object.

virtual Port &	getPort (const std::string &if_name, PortID idx=InvalidPortID)
	Get a port with a given name and index.

virtual void	startup ()
	startup() is the final initialization call before simulation.

DrainState	drain () override
	Provide a default implementation of the drain interface for objects that don't need draining.

virtual void	memWriteback ()
	Write back dirty buffers to memory using functional writes.

virtual void	memInvalidate ()
	Invalidate the contents of memory buffers.

void	serialize (CheckpointOut &cp) const override
	Serialize an object.

void	unserialize (CheckpointIn &cp) override
	Unserialize an object.

Public Member Functions inherited from gem5::EventManager
EventQueue *	eventQueue () const

void	schedule (Event &event, Tick when)

void	deschedule (Event &event)

void	reschedule (Event &event, Tick when, bool always=false)

void	schedule (Event *event, Tick when)

void	deschedule (Event *event)

void	reschedule (Event *event, Tick when, bool always=false)

void	wakeupEventQueue (Tick when=(Tick) -1)
	This function is not needed by the usual gem5 event loop but may be necessary in derived EventQueues which host gem5 on other schedulers.

void	setCurTick (Tick newVal)

	EventManager (EventManager &em)
	Event manger manages events in the event queue.

	EventManager (EventManager *em)

	EventManager (EventQueue *eq)

Public Member Functions inherited from gem5::Serializable
	Serializable ()

virtual	~Serializable ()

void	serializeSection (CheckpointOut &cp, const char *name) const
	Serialize an object into a new section.

void	serializeSection (CheckpointOut &cp, const std::string &name) const

void	unserializeSection (CheckpointIn &cp, const char *name)
	Unserialize an a child object.

void	unserializeSection (CheckpointIn &cp, const std::string &name)

Public Member Functions inherited from gem5::Drainable
DrainState	drainState () const
	Return the current drain state of an object.

Public Member Functions inherited from gem5::statistics::Group
	Group (Group parent, const char name=nullptr)
	Construct a new statistics group.

virtual	~Group ()

virtual void	regStats ()
	Callback to set stat parameters.

virtual void	resetStats ()
	Callback to reset stats.

virtual void	preDumpStats ()
	Callback before stats are dumped.

void	addStat (statistics::Info *info)
	Register a stat with this group.

const std::map< std::string, Group * > &	getStatGroups () const
	Get all child groups associated with this object.

const std::vector< Info * > &	getStats () const
	Get all stats associated with this object.

void	addStatGroup (const char name, Group block)
	Add a stat block as a child of this block.

const Info *	resolveStat (std::string name) const
	Resolve a stat by its name within this group.

void	mergeStatGroup (Group *block)
	Merge the contents (stats & children) of a block to this block.

	Group ()=delete

	Group (const Group &)=delete

Group &	operator= (const Group &)=delete

Public Member Functions inherited from gem5::Named
	Named (const std::string &name_)

virtual	~Named ()=default

virtual std::string	name () const

Static Public Attributes
static const uint32_t	VersionMajor = 1

static const uint32_t	VersionMinor = 0

Protected Types
typedef std::unordered_map< uint64_t, Sector * >	SectorTable

Protected Attributes
std::string	filename

DiskImage *	child

SectorTable *	table

Protected Attributes inherited from gem5::DiskImage
bool	initialized

Protected Attributes inherited from gem5::SimObject
const SimObjectParams &	_params
	Cached copy of the object parameters.

Protected Attributes inherited from gem5::EventManager
EventQueue *	eventq
	A pointer to this object's event queue.

Additional Inherited Members
Static Public Member Functions inherited from gem5::SimObject
static void	serializeAll (const std::string &cpt_dir)
	Create a checkpoint by serializing all SimObjects in the system.

static SimObject *	find (const char *name)
	Find the SimObject with the given name and return a pointer to it.

static void	setSimObjectResolver (SimObjectResolver *resolver)
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

static SimObjectResolver *	getSimObjectResolver ()
	There is a single object name resolver, and it is only set when simulation is restoring from checkpoints.

Static Public Member Functions inherited from gem5::Serializable
static const std::string &	currentSection ()
	Gets the fully-qualified name of the active section.

static void	generateCheckpointOut (const std::string &cpt_dir, std::ofstream &outstream)
	Generate a checkpoint file so that the serialization can be routed to it.

Protected Member Functions inherited from gem5::Drainable
	Drainable ()

virtual	~Drainable ()

virtual void	drainResume ()
	Resume execution after a successful drain.

void	signalDrainDone () const
	Signal that an object is drained.

Detailed Description

Specialization for accessing a copy-on-write disk image layer.

A copy-on-write(COW) layer must be stacked on top of another disk image layer this layer can be another CowDiskImage, or a RawDiskImage.

This object is designed to provide a mechanism for persistant changes to a main disk image, or to provide a place for temporary changes to the image to take place that later may be thrown away.

Definition at line 107 of file disk_image.hh.

Member Typedef Documentation

◆ Params

typedef CowDiskImageParams gem5::CowDiskImage::Params

Definition at line 126 of file disk_image.hh.

◆ SectorTable

typedef std::unordered_map<uint64_t, Sector *> gem5::CowDiskImage::SectorTable

protected

Definition at line 118 of file disk_image.hh.

Constructor & Destructor Documentation

◆ CowDiskImage()

gem5::CowDiskImage::CowDiskImage ( const Params & p )

Definition at line 171 of file disk_image.cc.

References fatal, filename, initSectorTable(), open(), gem5::MipsISA::p, gem5::registerExitCallback(), and save().

◆ ~CowDiskImage()

gem5::CowDiskImage::~CowDiskImage ( )

Definition at line 188 of file disk_image.cc.

References gem5::ArmISA::i, and table.

Member Function Documentation

◆ initSectorTable()

void gem5::CowDiskImage::initSectorTable ( int hash_size )

Definition at line 285 of file disk_image.cc.

References gem5::DiskImage::initialized, and table.

Referenced by CowDiskImage().

◆ notifyFork()

void gem5::CowDiskImage::notifyFork ( )

overridevirtual

Notify a child process of a fork.

SimObjects are told that the process is going to be forked.

Forking is a process of splitting a process in to two processes, which is then used for multiprocessing.

When calling fork in gem5, we need to ensure that resources shared between the parent and the child are consistent. This method is intended to be overloaded to handle that. For example, an object could use this method to re-open input files to get a separate file description with a private file offset.

This method is only called in the child of the fork. The call takes place in a drained system.

Reimplemented from gem5::Drainable.

Definition at line 200 of file disk_image.cc.

References filename, inform, and gem5::SimObject::params().