sync0sync.ic File Reference

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Functions
UNIV_INTERN void	mutex_set_waiters (ib_mutex_t *mutex, ulint n)
UNIV_INTERN void	mutex_spin_wait (ib_mutex_t *mutex, const char *file_name, ulint line)
UNIV_INTERN void	mutex_set_debug_info (ib_mutex_t *mutex, const char *file_name, ulint line)
UNIV_INTERN void	mutex_signal_object (ib_mutex_t *mutex)
UNIV_INLINE byte	ib_mutex_test_and_set (ib_mutex_t *mutex)
UNIV_INLINE void	mutex_reset_lock_word (ib_mutex_t *mutex)
UNIV_INLINE lock_word_t	mutex_get_lock_word (const ib_mutex_t *mutex)
UNIV_INLINE ulint	mutex_get_waiters (const ib_mutex_t *mutex)
UNIV_INLINE void	mutex_exit_func (ib_mutex_t *mutex)
UNIV_INLINE void	mutex_enter_func (ib_mutex_t *mutex, const char *file_name, ulint line)
UNIV_INLINE void	os_atomic_dec_ulint_func (ib_mutex_t *mutex, volatile ulint *var, ulint delta)
UNIV_INLINE void	os_atomic_inc_ulint_func (ib_mutex_t *mutex, volatile ulint *var, ulint delta)

Detailed Description

Mutex, the basic synchronization primitive

Created 9/5/1995 Heikki Tuuri

Function Documentation

UNIV_INLINE byte ib_mutex_test_and_set

(

ib_mutex_t *

mutex

)

Performs an atomic test-and-set instruction to the lock_word field of a mutex.

Returns

the previous value of lock_word: 0 or 1

Parameters

mutex

in: mutex

UNIV_INLINE void mutex_enter_func	(	ib_mutex_t *	mutex,
		const char *	file_name,
		ulint	line
	)

Locks a mutex for the current thread. If the mutex is reserved, the function spins a preset time (controlled by SYNC_SPIN_ROUNDS), waiting for the mutex before suspending the thread.

Parameters

mutex	in: pointer to mutex
file_name	in: file name where locked
line	in: line where locked

UNIV_INLINE void mutex_exit_func

(

ib_mutex_t *

mutex

)

NOTE! Use the corresponding macro mutex_exit(), not directly this function! Unlocks a mutex owned by the current thread.

Parameters

mutex

in: pointer to mutex

UNIV_INLINE lock_word_t mutex_get_lock_word

(

const ib_mutex_t *

mutex

)

Gets the value of the lock word.

Parameters

mutex

in: mutex

UNIV_INLINE ulint mutex_get_waiters

(

const ib_mutex_t *

mutex

)

Gets the waiters field in a mutex.

Returns

value to set

< declared volatile to ensure that the value is read from memory

Parameters

mutex

in: mutex

UNIV_INLINE void mutex_reset_lock_word

(

ib_mutex_t *

mutex

)

Performs a reset instruction to the lock_word field of a mutex. This instruction also serializes memory operations to the program order.

Parameters

mutex

in: mutex

UNIV_INTERN void mutex_set_debug_info	(	ib_mutex_t *	mutex,
		const char *	file_name,
		ulint	line
	)

Sets the debug information for a reserved mutex. in: line where requested

Parameters

mutex	in: mutex
file_name	in: file where requested

UNIV_INTERN void mutex_set_waiters	(	ib_mutex_t *	mutex,
		ulint	n
	)

Sets the waiters field in a mutex. in: value to set

Parameters

mutex

in: mutex

UNIV_INTERN void mutex_signal_object

(

ib_mutex_t *

mutex

)

Releases the threads waiting in the primary wait array for this mutex. in: mutex

UNIV_INTERN void mutex_spin_wait	(	ib_mutex_t *	mutex,
		const char *	file_name,
		ulint	line
	)

Reserves a mutex for the current thread. If the mutex is reserved, the function spins a preset time (controlled by SYNC_SPIN_ROUNDS) waiting for the mutex before suspending the thread. in: line where requested

Parameters

mutex	in: pointer to mutex
file_name	in: file name where mutex requested

UNIV_INLINE void os_atomic_dec_ulint_func	(	ib_mutex_t *	mutex,
		volatile ulint *	var,
		ulint	delta
	)

Function that uses a mutex to decrement a variable atomically

Parameters

mutex	in: mutex guarding the dec
var	in/out: variable to decrement
delta	in: delta to decrement

UNIV_INLINE void os_atomic_inc_ulint_func	(	ib_mutex_t *	mutex,
		volatile ulint *	var,
		ulint	delta
	)

Function that uses a mutex to increment a variable atomically

Parameters

mutex	in: mutex guarding the increment
var	in/out: variable to increment
delta	in: delta to increment