A map of MemMapSlots indexed by their keys, with read/write slot locking. More...

#include <MemMap.h>

Collaboration diagram for Ipc::MemMap:

Classes
class	Shared
	data shared across maps in different processes More...

Public Types
typedef MemMapSlot	Slot

typedef Mem::Owner< Shared >	Owner

Public Member Functions
	MemMap (const char *const aPath)

Slot *	openForWriting (const cache_key *const key, sfileno &fileno)

Slot *	openForWritingAt (sfileno fileno, bool overwriteExisting=true)

void	closeForWriting (const sfileno fileno)
	successfully finish writing the entry

void	switchWritingToReading (const sfileno fileno)
	stop writing the locked entry and start reading it

const Slot *	peekAtReader (const sfileno fileno) const
	only works on locked entries; returns nil unless the slot is readable

void	free (const sfileno fileno)
	mark the slot as waiting to be freed and, if possible, free it

const Slot *	openForReading (const cache_key *const key, sfileno &fileno)
	open slot for reading, increments read level

const Slot *	openForReadingAt (const sfileno fileno)
	open slot for reading, increments read level

void	closeForReading (const sfileno fileno)
	close slot after reading, decrements read level

bool	full () const
	there are no empty slots left

bool	valid (const int n) const
	whether n is a valid slot coordinate

int	entryCount () const
	number of used slots

int	entryLimit () const
	maximum number of slots that can be used

void	updateStats (ReadWriteLockStats &stats) const
	adds approximate current stats to the supplied ones

Static Public Member Functions
static Owner *	Init (const char *const path, const int limit)
	initialize shared memory

Public Attributes
MemMapCleaner *	cleaner

Static Protected Member Functions
static Owner *	Init (const char *const path, const int limit, const size_t extrasSize)

Protected Attributes
const SBuf	path
	cache_dir path, used for logging

Mem::Pointer< Shared >	shared

Private Member Functions
int	slotIndexByKey (const cache_key *const key) const

Slot &	slotByKey (const cache_key *const key)

Slot *	openForReading (Slot &s)

void	abortWriting (const sfileno fileno)
	terminate writing the entry, freeing its slot for others to use

void	freeIfNeeded (Slot &s)

void	freeLocked (Slot &s, bool keepLocked)
	unconditionally frees the already exclusively locked slot and releases lock

Detailed Description

Definition at line 56 of file MemMap.h.

Member Typedef Documentation

◆ Owner

typedef Mem::Owner<Shared> Ipc::MemMap::Owner

Definition at line 77 of file MemMap.h.

◆ Slot

typedef MemMapSlot Ipc::MemMap::Slot

Definition at line 59 of file MemMap.h.

Constructor & Destructor Documentation

◆ MemMap()

Ipc::MemMap::MemMap ( const char *const aPath )

Definition at line 16 of file MemMap.cc.

References assert, debugs, path, and shared.

Member Function Documentation

◆ abortWriting()

void Ipc::MemMap::abortWriting ( const sfileno fileno )

private

Definition at line 114 of file MemMap.cc.

References assert, debugs, and Ipc::MemMapSlot::writing().

◆ closeForReading()

void Ipc::MemMap::closeForReading ( const sfileno fileno )

Definition at line 207 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::lock, Ipc::MemMapSlot::reading(), and Ipc::ReadWriteLock::unlockShared().

Referenced by get_session_cb(), and remove_session_cb().

◆ closeForWriting()

void Ipc::MemMap::closeForWriting ( const sfileno fileno )

Definition at line 91 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::unlockExclusive(), and Ipc::MemMapSlot::writing().

Referenced by store_session_cb().

◆ entryCount()

int Ipc::MemMap::entryCount ( ) const

Definition at line 224 of file MemMap.cc.

◆ entryLimit()

int Ipc::MemMap::entryLimit ( ) const

Definition at line 218 of file MemMap.cc.

◆ free()

void Ipc::MemMap::free ( const sfileno fileno )

Definition at line 138 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::lockExclusive(), and Ipc::MemMapSlot::waitingToBeFreed.

Referenced by remove_session_cb().

◆ freeIfNeeded()

void Ipc::MemMap::freeIfNeeded ( Slot & s )

private

◆ freeLocked()

void Ipc::MemMap::freeLocked	(	Slot &	s,
		bool	keepLocked
	)

private

Definition at line 276 of file MemMap.cc.

References debugs, Ipc::MemMapSlot::empty(), Ipc::MemMapSlot::key, Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::unlockExclusive(), and Ipc::MemMapSlot::waitingToBeFreed.

◆ full()

bool Ipc::MemMap::full ( ) const

Definition at line 230 of file MemMap.cc.

◆ Init() [1/2]

Ipc::MemMap::Owner * Ipc::MemMap::Init	(	const char *const	path,
		const int	limit
	)

static

Definition at line 36 of file MemMap.cc.

Referenced by SharedSessionCacheRr::create().

◆ Init() [2/2]

Ipc::MemMap::Owner * Ipc::MemMap::Init	(	const char *const	path,
		const int	limit,
		const size_t	extrasSize
	)

staticprotected

Definition at line 27 of file MemMap.cc.

References assert, debugs, and shm_new.

◆ openForReading() [1/2]

const Ipc::MemMap::Slot * Ipc::MemMap::openForReading	(	const cache_key *const	key,
		sfileno &	fileno
	)

Definition at line 153 of file MemMap.cc.

References debugs, and storeKeyText().

Referenced by get_session_cb(), and remove_session_cb().

◆ openForReading() [2/2]

Slot * Ipc::MemMap::openForReading ( Slot & s )

private

◆ openForReadingAt()

const Ipc::MemMap::Slot * Ipc::MemMap::openForReadingAt ( const sfileno fileno )

Definition at line 174 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::empty(), Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::lockShared(), Ipc::ReadWriteLock::unlockShared(), and Ipc::MemMapSlot::waitingToBeFreed.

◆ openForWriting()

Ipc::MemMap::Slot * Ipc::MemMap::openForWriting	(	const cache_key *const	key,
		sfileno &	fileno
	)

finds, locks and return a slot for an empty key position, erasing the old entry (if any)

Definition at line 42 of file MemMap.cc.

References debugs, and storeKeyText().

Referenced by store_session_cb().

◆ openForWritingAt()

Ipc::MemMap::Slot * Ipc::MemMap::openForWritingAt	(	sfileno	fileno,
		bool	overwriteExisting = `true`
	)

locks and returns a slot for the empty fileno position; if overwriteExisting is false and the position is not empty, returns nil

Definition at line 57 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::empty(), Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::lockExclusive(), Ipc::MemMapSlot::reading(), Ipc::ReadWriteLock::unlockExclusive(), Ipc::MemMapSlot::waitingToBeFreed, and Ipc::MemMapSlot::writing().

◆ peekAtReader()

const Ipc::MemMap::Slot * Ipc::MemMap::peekAtReader ( const sfileno fileno ) const

Definition at line 125 of file MemMap.cc.

References assert, Ipc::MemMapSlot::reading(), and Ipc::MemMapSlot::writing().

◆ slotByKey()

Ipc::MemMap::Slot & Ipc::MemMap::slotByKey ( const cache_key *const key )

private

Definition at line 269 of file MemMap.cc.

◆ slotIndexByKey()

int Ipc::MemMap::slotIndexByKey ( const cache_key *const key ) const

private

Definition at line 262 of file MemMap.cc.

References hash_key(), and MEMMAP_SLOT_KEY_SIZE.

◆ switchWritingToReading()

void Ipc::MemMap::switchWritingToReading ( const sfileno fileno )

Definition at line 102 of file MemMap.cc.

References assert, debugs, Ipc::MemMapSlot::lock, Ipc::ReadWriteLock::switchExclusiveToShared(), and Ipc::MemMapSlot::writing().

◆ updateStats()

void Ipc::MemMap::updateStats ( ReadWriteLockStats & stats ) const

Definition at line 236 of file MemMap.cc.

◆ valid()

bool Ipc::MemMap::valid ( const int n ) const

Definition at line 243 of file MemMap.cc.

Member Data Documentation

◆ cleaner

MemMapCleaner* Ipc::MemMap::cleaner

The cleaner MemMapCleaner::noteFreeMapSlot method called when a readable entry is freed.

Definition at line 123 of file MemMap.h.

◆ path

const SBuf Ipc::MemMap::path

protected

Definition at line 128 of file MemMap.h.

Referenced by MemMap().

◆ shared

Mem::Pointer<Shared> Ipc::MemMap::shared

protected

Definition at line 129 of file MemMap.h.

Referenced by MemMap().

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

squid/src/ipc/MemMap.h
squid/src/ipc/MemMap.cc

Classes

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Static Protected Member Functions

Protected Attributes

Private Member Functions

Detailed Description

Member Typedef Documentation

◆ Owner

◆ Slot

Constructor & Destructor Documentation

◆ MemMap()

Member Function Documentation

◆ abortWriting()

◆ closeForReading()

◆ closeForWriting()

◆ entryCount()

◆ entryLimit()

◆ free()

◆ freeIfNeeded()

◆ freeLocked()

◆ full()

◆ Init() [1/2]

◆ Init() [2/2]

◆ openForReading() [1/2]

◆ openForReading() [2/2]

◆ openForReadingAt()

◆ openForWriting()

◆ openForWritingAt()

◆ peekAtReader()

◆ slotByKey()

◆ slotIndexByKey()

◆ switchWritingToReading()

◆ updateStats()

◆ valid()

Member Data Documentation

◆ cleaner

◆ path

◆ shared