occ_rwlock Struct Reference

A multiple-reader/single-writer lock based on pthreads (blocking) More...

#include <latches.h>

Public Member Functions
	occ_rwlock ()
	~occ_rwlock ()
void	acquire_read ()
	The normal way to acquire a read lock. More...
void	release_read ()
	The normal way to release a read lock. More...
void	acquire_write ()
	The normal way to acquire a write lock. More...
void	release_write ()
	The normal way to release a write lock. More...

Private Types
enum	{ WRITER = 1, READER = 2 }

Private Attributes
unsigned int volatile	_active_count
occ_rlock	_read_lock
occ_wlock	_write_lock
pthread_mutex_t	_read_write_mutex
pthread_cond_t	_read_cond
pthread_cond_t	_write_cond

Detailed Description

A multiple-reader/single-writer lock based on pthreads (blocking)

Use this to protect data structures that get hammered by reads and where updates are very rare. It is used in the storage manager by the histograms (histo.cpp), and in place of some mutexen, where strict exclusion isn't required.

This lock is used in the storage manager by the checkpoint thread (the only acquire-writer) and other threads to be sure they don't do certain nasty things when a checkpoint is going on.

The idiom for using these locks is that the qnode is on a threads's stack, so the qnode implicitly identifies the owning thread.

See also: REFSYNC

Member Enumeration Documentation

anonymous enum

anonymous enum

private

skip

Enumerator
WRITER
READER

Constructor & Destructor Documentation

occ_rwlock()

occ_rwlock::occ_rwlock

(

)

~occ_rwlock()

occ_rwlock::~occ_rwlock

(

)

Member Function Documentation

acquire_read()

void occ_rwlock::acquire_read

(

)

The normal way to acquire a read lock.

acquire_write()

void occ_rwlock::acquire_write

(

)

The normal way to acquire a write lock.

release_read()

void occ_rwlock::release_read

(

)

The normal way to release a read lock.

release_write()

void occ_rwlock::release_write

(

)

The normal way to release a write lock.

Member Data Documentation

_active_count

unsigned int volatile occ_rwlock::_active_count

private

_read_cond

pthread_cond_t occ_rwlock::_read_cond

private

_read_lock

occ_rlock occ_rwlock::_read_lock

private

_read_write_mutex

pthread_mutex_t occ_rwlock::_read_write_mutex

private

_write_cond

pthread_cond_t occ_rwlock::_write_cond

private

_write_lock

occ_wlock occ_rwlock::_write_lock

private

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

• src/sm/latches.h
• src/sm/latches.cpp