sync0rw.ic File Reference

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Functions
UNIV_INTERN void	rw_lock_s_lock_spin (rw_lock_t *lock, ulint pass, const char *file_name, ulint line)
UNIV_INTERN void	rw_lock_add_debug_info (rw_lock_t *lock, ulint pass, ulint lock_type, const char *file_name, ulint line)
UNIV_INTERN void	rw_lock_remove_debug_info (rw_lock_t *lock, ulint pass, ulint lock_type)
UNIV_INLINE ulint	rw_lock_get_waiters (const rw_lock_t *lock)
UNIV_INLINE void	rw_lock_set_waiter_flag (rw_lock_t *lock)
UNIV_INLINE void	rw_lock_reset_waiter_flag (rw_lock_t *lock)
UNIV_INLINE ulint	rw_lock_get_writer (const rw_lock_t *lock)
UNIV_INLINE ulint	rw_lock_get_reader_count (const rw_lock_t *lock)
UNIV_INLINE ib_mutex_t *	rw_lock_get_mutex (rw_lock_t *lock)
UNIV_INLINE ulint	rw_lock_get_x_lock_count (const rw_lock_t *lock)
UNIV_INLINE ibool	rw_lock_lock_word_decr (rw_lock_t *lock, ulint amount)
UNIV_INLINE lint	rw_lock_lock_word_incr (rw_lock_t *lock, ulint amount)
UNIV_INLINE void	rw_lock_set_writer_id_and_recursion_flag (rw_lock_t *lock, ibool recursive)
UNIV_INLINE ibool	rw_lock_s_lock_low (rw_lock_t *lock, ulint pass)
UNIV_INLINE ibool const char ulint line	if (!rw_lock_lock_word_decr(lock, 1))
	rw_lock_add_debug_info (lock, pass, RW_LOCK_SHARED, file_name, line)
	return (TRUE)
UNIV_INLINE void	rw_lock_s_lock_func (rw_lock_t *lock, ulint pass, const char *file_name, ulint line)
UNIV_INLINE ibool	rw_lock_x_lock_func_nowait (rw_lock_t *lock, const char *file_name, ulint line)
UNIV_INLINE void	rw_lock_s_unlock_func (ulint pass, rw_lock_t *lock)
UNIV_INLINE void	rw_lock_x_unlock_func (ulint pass, rw_lock_t *lock)

Variables
UNIV_INLINE ibool const char *	file_name
lock	last_s_file_name = file_name
lock	last_s_line = line

Detailed Description

The read-write lock (for threads)

Created 9/11/1995 Heikki Tuuri

Function Documentation

UNIV_INLINE ibool const char ulint line if

(

!

rw_lock_lock_word_decrlock, 1

)

< in: line where requested

UNIV_INTERN void rw_lock_add_debug_info	(	rw_lock_t *	lock,
		ulint	pass,
		ulint	lock_type,
		const char *	file_name,
		ulint	line
	)

Inserts the debug information for an rw-lock. in: line where requested

Parameters

lock	in: rw-lock
pass	in: pass value
lock_type	in: lock type
file_name	in: file where requested

UNIV_INLINE ulint rw_lock_get_reader_count

(

const rw_lock_t *

lock

)

Returns the number of readers.

Returns

number of readers

Parameters

lock	in: rw-lock

UNIV_INLINE ulint rw_lock_get_waiters

(

const rw_lock_t *

lock

)

Check if there are threads waiting for the rw-lock.

Returns

1 if waiters, 0 otherwise

Parameters

lock	in: rw-lock

UNIV_INLINE ulint rw_lock_get_writer

(

const rw_lock_t *

lock

)

Returns the write-status of the lock - this function made more sense with the old rw_lock implementation.

Returns

RW_LOCK_NOT_LOCKED, RW_LOCK_EX, RW_LOCK_WAIT_EX

Parameters

lock	in: rw-lock

UNIV_INLINE ulint rw_lock_get_x_lock_count

(

const rw_lock_t *

lock

)

Returns the value of writer_count for the lock. Does not reserve the lock mutex, so the caller must be sure it is not changed during the call.

Returns

value of writer_count

Parameters

lock	in: rw-lock

UNIV_INLINE ibool rw_lock_lock_word_decr	(	rw_lock_t *	lock,
		ulint	amount
	)

Two different implementations for decrementing the lock_word of a rw_lock: one for systems supporting atomic operations, one for others. This does does not support recusive x-locks: they should be handled by the caller and need not be atomic since they are performed by the current lock holder. Returns true if the decrement was made, false if not.

Returns

TRUE if decr occurs

Parameters

lock	in/out: rw-lock
amount	in: amount to decrement

UNIV_INLINE lint rw_lock_lock_word_incr	(	rw_lock_t *	lock,
		ulint	amount
	)

Increments lock_word the specified amount and returns new value.

Returns

lock->lock_word after increment

Parameters

lock	in/out: rw-lock
amount	in: amount of increment

UNIV_INTERN void rw_lock_remove_debug_info	(	rw_lock_t *	lock,
		ulint	pass,
		ulint	lock_type
	)

Removes a debug information struct for an rw-lock. in: lock type

Parameters

lock	in: rw-lock
pass	in: pass value

UNIV_INLINE void rw_lock_reset_waiter_flag

(

rw_lock_t *

lock

)

Resets lock->waiters to 0. It is not an error if lock->waiters is already 0. On platforms where ATOMIC builtins are used this function enforces a memory barrier.

Parameters

lock	in/out: rw-lock

UNIV_INLINE void rw_lock_s_lock_func	(	rw_lock_t *	lock,
		ulint	pass,
		const char *	file_name,
		ulint	line
	)

NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in shared mode for the current thread. If the rw-lock is locked in exclusive mode, or there is an exclusive lock request waiting, the function spins a preset time (controlled by SYNC_SPIN_ROUNDS), waiting for the lock, before suspending the thread.

Parameters

lock	in: pointer to rw-lock
pass	in: pass value; != 0, if the lock will be passed to another thread to unlock
file_name	in: file name where lock requested
line	in: line where requested

UNIV_INLINE ibool rw_lock_s_lock_low	(	rw_lock_t *	lock,
		ulint	pass
	)

Low-level function which tries to lock an rw-lock in s-mode. Performs no spinning.

Returns

TRUE if success

Parameters

lock	in: pointer to rw-lock

UNIV_INTERN void rw_lock_s_lock_spin	(	rw_lock_t *	lock,
		ulint	pass,
		const char *	file_name,
		ulint	line
	)

Lock an rw-lock in shared mode for the current thread. If the rw-lock is locked in exclusive mode, or there is an exclusive lock request waiting, the function spins a preset time (controlled by SYNC_SPIN_ROUNDS), waiting for the lock before suspending the thread. in: line where requested

Parameters

lock	in: pointer to rw-lock
pass	in: pass value; != 0, if the lock will be passed to another thread to unlock
file_name	in: file name where lock requested

UNIV_INLINE void rw_lock_s_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

Releases a shared mode lock.

Parameters

pass	in: pass value; != 0, if the lock may have been passed to another thread to unlock
lock	in/out: rw-lock

UNIV_INLINE void rw_lock_set_waiter_flag

(

rw_lock_t *

lock

)

Sets lock->waiters to 1. It is not an error if lock->waiters is already

1. On platforms where ATOMIC builtins are used this function enforces a memory barrier.

Parameters

lock	in/out: rw-lock

UNIV_INLINE void rw_lock_set_writer_id_and_recursion_flag	(	rw_lock_t *	lock,
		ibool	recursive
	)

This function sets the lock->writer_thread and lock->recursive fields. For platforms where we are using atomic builtins instead of lock->mutex it sets the lock->writer_thread field using atomics to ensure memory ordering. Note that it is assumed that the caller of this function effectively owns the lock i.e.: nobody else is allowed to modify lock->writer_thread at this point in time. The protocol is that lock->writer_thread MUST be updated BEFORE the lock->recursive flag is set.

Parameters

lock	in/out: lock to work on
recursive	in: TRUE if recursion allowed

UNIV_INLINE ibool rw_lock_x_lock_func_nowait	(	rw_lock_t *	lock,
		const char *	file_name,
		ulint	line
	)

NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in exclusive mode for the current thread if the lock can be obtained immediately.

Returns

TRUE if success

Parameters

lock	in: pointer to rw-lock
file_name	in: file name where lock requested
line	in: line where requested

UNIV_INLINE void rw_lock_x_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

Releases an exclusive mode lock.

Parameters

pass	in: pass value; != 0, if the lock may have been passed to another thread to unlock
lock	in/out: rw-lock

Variable Documentation

UNIV_INLINE ibool const char* file_name

< in: pass value; != 0, if the lock will be passed to another thread to unlock in: file name where lock requested