The read-write lock (for threads) More...

#include "os0event.h"

Functions
void	rw_lock_s_lock_spin (rw_lock_t *lock, ulint pass, ut::Location location)
	Lock an rw-lock in shared mode for the current thread. More...

void	rw_lock_add_debug_info (rw_lock_t *lock, ulint pass, ulint lock_type, ut::Location location)
	Inserts the debug information for an rw-lock. More...

void	rw_lock_remove_debug_info (rw_lock_t *lock, ulint pass, ulint lock_type)
	Removes a debug information struct for an rw-lock. More...

static bool	rw_lock_get_waiters (const rw_lock_t *lock)
	Check if there are threads waiting for the rw-lock. More...

static void	rw_lock_set_waiter_flag (rw_lock_t *lock)
	Sets lock->waiters to true. More...

static void	rw_lock_reset_waiter_flag (rw_lock_t *lock)
	Resets lock->waiters to false. More...

static 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. More...

static ulint	rw_lock_get_reader_count (const rw_lock_t *lock)
	Returns the number of readers (s-locks). More...

static ulint	rw_lock_get_x_lock_count (const rw_lock_t *lock)
	Returns the value of writer_count for the lock. More...

static ulint	rw_lock_get_sx_lock_count (const rw_lock_t *lock)
	Returns the number of sx-lock for the lock. More...

ALWAYS_INLINE bool	rw_lock_lock_word_decr (rw_lock_t *lock, ulint amount, lint threshold)
	Two different implementations for decrementing the lock_word of a rw_lock: one for systems supporting atomic operations, one for others. More...

static lint	rw_lock_lock_word_incr (rw_lock_t *lock, ulint amount)
	Increments lock_word the specified amount and returns new value. More...

static void	rw_lock_set_writer_id_and_recursion_flag (rw_lock_t *lock, bool recursive)

ALWAYS_INLINE bool	rw_lock_s_lock_low (rw_lock_t *lock, ulint pass, ut::Location location)
	Low-level function which tries to lock an rw-lock in s-mode. More...

static void	rw_lock_s_lock_func (rw_lock_t *lock, ulint pass, ut::Location location)
	NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in shared mode for the current thread. More...

static bool	rw_lock_x_lock_func_nowait (rw_lock_t *lock, ut::Location location)
	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. More...

static void	rw_lock_s_unlock_func (ulint pass, rw_lock_t *lock)
	Releases a shared mode lock. More...

static void	rw_lock_x_unlock_func (ulint pass, rw_lock_t *lock)
	Releases an exclusive mode lock. More...

static void	rw_lock_sx_unlock_func (ulint pass, rw_lock_t *lock)
	Releases a sx mode lock. More...

static void	pfs_rw_lock_create_func (mysql_pfs_key_t key, rw_lock_t *lock, latch_id_t id, ut::Location clocation)

static void	pfs_rw_lock_x_lock_func (rw_lock_t *lock, ulint pass, ut::Location location)
	Performance schema instrumented wrap function for rw_lock_x_lock_func() NOTE! Please use the corresponding macro rw_lock_x_lock(), not directly this function! More...

static bool	pfs_rw_lock_x_lock_func_nowait (rw_lock_t *lock, ut::Location location)
	Performance schema instrumented wrap function for rw_lock_x_lock_func_nowait() NOTE! Please use the corresponding macro rw_lock_x_lock_func(), not directly this function! More...

static void	pfs_rw_lock_free_func (rw_lock_t *lock)
	Performance schema instrumented wrap function for rw_lock_free_func() NOTE! Please use the corresponding macro rw_lock_free(), not directly this function! More...

ALWAYS_INLINE void	pfs_rw_lock_s_lock_func (rw_lock_t *lock, ulint pass, ut::Location location)
	Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function! More...

static void	pfs_rw_lock_sx_lock_func (rw_lock_t *lock, ulint pass, ut::Location location)
	Performance schema instrumented wrap function for rw_lock_sx_lock_func() NOTE! Please use the corresponding macro rw_lock_sx_lock(), not directly this function! More...

static bool	pfs_rw_lock_s_lock_low (rw_lock_t *lock, ulint pass, ut::Location location)

static bool	pfs_rw_lock_sx_lock_low (rw_lock_t *lock, ulint pass, ut::Location location)
	Performance schema instrumented wrap function for rw_lock_sx_lock_nowait() NOTE! Please use the corresponding macro, not directly this function! More...

static void	pfs_rw_lock_x_unlock_func (ulint pass, rw_lock_t *lock)
	Performance schema instrumented wrap function for rw_lock_x_unlock_func() NOTE! Please use the corresponding macro rw_lock_x_unlock(), not directly this function! More...

static void	pfs_rw_lock_sx_unlock_func (ulint pass, rw_lock_t *lock)

ALWAYS_INLINE void	pfs_rw_lock_s_unlock_func (ulint pass, rw_lock_t *lock)
	Performance schema instrumented wrap function for rw_lock_s_unlock_func() NOTE! Please use the corresponding macro rw_lock_s_unlock(), not directly this function! More...

Detailed Description

The read-write lock (for threads)

Created 9/11/1995 Heikki Tuuri

Function Documentation

◆ pfs_rw_lock_create_func()

static void pfs_rw_lock_create_func	(	mysql_pfs_key_t	key,
		rw_lock_t *	lock,
		latch_id_t	id,
		ut::Location	clocation
	)

inlinestatic

◆ pfs_rw_lock_free_func()

static void pfs_rw_lock_free_func ( rw_lock_t * lock )

inlinestatic

Performance schema instrumented wrap function for rw_lock_free_func() NOTE! Please use the corresponding macro rw_lock_free(), not directly this function!

Parameters

lock	in: pointer to rw-lock

◆ pfs_rw_lock_s_lock_func()

ALWAYS_INLINE void pfs_rw_lock_s_lock_func	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inline

Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function!

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; != 0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

◆ pfs_rw_lock_s_lock_low()

static bool pfs_rw_lock_s_lock_low	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inlinestatic

◆ pfs_rw_lock_s_unlock_func()

ALWAYS_INLINE void pfs_rw_lock_s_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inline

Performance schema instrumented wrap function for rw_lock_s_unlock_func() NOTE! Please use the corresponding macro rw_lock_s_unlock(), not directly this function!

Parameters

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

◆ pfs_rw_lock_sx_lock_func()

static void pfs_rw_lock_sx_lock_func	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inlinestatic

Performance schema instrumented wrap function for rw_lock_sx_lock_func() NOTE! Please use the corresponding macro rw_lock_sx_lock(), not directly this function!

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; != 0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

◆ pfs_rw_lock_sx_lock_low()

static bool pfs_rw_lock_sx_lock_low	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inlinestatic

Performance schema instrumented wrap function for rw_lock_sx_lock_nowait() NOTE! Please use the corresponding macro, not directly this function!

Parameters

[in]	lock	pointer to rw-loxk
[in]	pass	pass value; != 0 if the lock will be passed to another thread to unlock
[in]	location	location where requested

Returns: true if success

◆ pfs_rw_lock_sx_unlock_func()

static void pfs_rw_lock_sx_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inlinestatic

◆ pfs_rw_lock_x_lock_func()

static void pfs_rw_lock_x_lock_func	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inlinestatic

Performance schema instrumented wrap function for rw_lock_x_lock_func() NOTE! Please use the corresponding macro rw_lock_x_lock(), not directly this function!

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; != 0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

◆ pfs_rw_lock_x_lock_func_nowait()

static bool pfs_rw_lock_x_lock_func_nowait	(	rw_lock_t *	lock,
		ut::Location	location
	)

inlinestatic

Performance schema instrumented wrap function for rw_lock_x_lock_func_nowait() NOTE! Please use the corresponding macro rw_lock_x_lock_func(), not directly this function!

Returns: true if success

Parameters

lock	in: pointer to rw-lock
location	in: line where requested

◆ pfs_rw_lock_x_unlock_func()

static void pfs_rw_lock_x_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inlinestatic

Performance schema instrumented wrap function for rw_lock_x_unlock_func() NOTE! Please use the corresponding macro rw_lock_x_unlock(), not directly this function!

◆ rw_lock_add_debug_info()

void rw_lock_add_debug_info	(	rw_lock_t *	lock,
		ulint	pass,
		ulint	lock_type,
		ut::Location	location
	)

Inserts the debug information for an rw-lock.

Parameters

[in]	lock	rw-lock
[in]	pass	pass value
[in]	lock_type	lock type
[in]	location	location where requested

◆ rw_lock_get_reader_count()

static ulint rw_lock_get_reader_count ( const rw_lock_t * lock )

inlinestatic

Returns the number of readers (s-locks).

Returns: number of readers

Parameters

lock	in: rw-lock

◆ rw_lock_get_sx_lock_count()

static ulint rw_lock_get_sx_lock_count ( const rw_lock_t * lock )

inlinestatic

Returns the number of sx-lock 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 sx-lock count

Parameters

lock	in: rw-lock

◆ rw_lock_get_waiters()

static bool rw_lock_get_waiters ( const rw_lock_t * lock )

inlinestatic

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

Returns: true if waiters, false otherwise

Parameters

lock	in: rw-lock

◆ rw_lock_get_writer()

static ulint rw_lock_get_writer ( const rw_lock_t * lock )

inlinestatic

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_X, RW_LOCK_X_WAIT, RW_LOCK_SX

Parameters

lock	in: rw-lock

◆ rw_lock_get_x_lock_count()

static ulint rw_lock_get_x_lock_count ( const rw_lock_t * lock )

inlinestatic

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

◆ rw_lock_lock_word_decr()

ALWAYS_INLINE bool rw_lock_lock_word_decr	(	rw_lock_t *	lock,
		ulint	amount,
		lint	threshold
	)

inline

Two different implementations for decrementing the lock_word of a rw_lock: one for systems supporting atomic operations, one for others.

Decrements lock_word the specified amount if it is greater than 0.

This does does not support recursive 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
threshold	in: threshold of judgement

◆ rw_lock_lock_word_incr()

static lint rw_lock_lock_word_incr	(	rw_lock_t *	lock,
		ulint	amount
	)

inlinestatic

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

◆ rw_lock_remove_debug_info()

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
lock_type	in: lock type

◆ rw_lock_reset_waiter_flag()

static void rw_lock_reset_waiter_flag ( rw_lock_t * lock )

inlinestatic

Resets lock->waiters to false.

It is not an error if lock->waiters is already false.

Parameters

lock	in/out: rw-lock

◆ rw_lock_s_lock_func()

static void rw_lock_s_lock_func	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inlinestatic

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 srv_n_spin_wait_rounds), waiting for the lock, before suspending the thread.

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; != 0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

◆ rw_lock_s_lock_low()

ALWAYS_INLINE bool rw_lock_s_lock_low	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

inline

Low-level function which tries to lock an rw-lock in s-mode.

Performs no spinning.

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; != 0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

Returns: true if success

◆ rw_lock_s_lock_spin()

void rw_lock_s_lock_spin	(	rw_lock_t *	lock,
		ulint	pass,
		ut::Location	location
	)

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 srv_n_spin_wait_rounds), waiting for the lock before suspending the thread.

Parameters

[in]	lock	pointer to rw-lock
[in]	pass	pass value; !=0, if the lock will be passed to another thread to unlock
[in]	location	location where requested

◆ rw_lock_s_unlock_func()

static void rw_lock_s_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inlinestatic

Releases a shared mode lock.

Parameters

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

◆ rw_lock_set_waiter_flag()

static void rw_lock_set_waiter_flag ( rw_lock_t * lock )

inlinestatic

Sets lock->waiters to true.

It is not an error if lock->waiters is already true.

Parameters

lock	in/out: rw-lock

◆ rw_lock_set_writer_id_and_recursion_flag()

static void rw_lock_set_writer_id_and_recursion_flag	(	rw_lock_t *	lock,
		bool	recursive
	)

inlinestatic

◆ rw_lock_sx_unlock_func()

static void rw_lock_sx_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inlinestatic

Releases a sx mode lock.

Parameters

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

◆ rw_lock_x_lock_func_nowait()

static bool rw_lock_x_lock_func_nowait	(	rw_lock_t *	lock,
		ut::Location	location
	)

inlinestatic

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.

Parameters

[in]	lock	pointer to rw-lock
[in]	location	location where requested

Returns: true if success

◆ rw_lock_x_unlock_func()

static void rw_lock_x_unlock_func	(	ulint	pass,
		rw_lock_t *	lock
	)

inlinestatic

Releases an exclusive mode lock.

Parameters

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

Functions

Detailed Description

Function Documentation

◆ pfs_rw_lock_create_func()

◆ pfs_rw_lock_free_func()

◆ pfs_rw_lock_s_lock_func()

◆ pfs_rw_lock_s_lock_low()

◆ pfs_rw_lock_s_unlock_func()

◆ pfs_rw_lock_sx_lock_func()

◆ pfs_rw_lock_sx_lock_low()

◆ pfs_rw_lock_sx_unlock_func()

◆ pfs_rw_lock_x_lock_func()

◆ pfs_rw_lock_x_lock_func_nowait()

◆ pfs_rw_lock_x_unlock_func()

◆ rw_lock_add_debug_info()

◆ rw_lock_get_reader_count()

◆ rw_lock_get_sx_lock_count()

◆ rw_lock_get_waiters()

◆ rw_lock_get_writer()

◆ rw_lock_get_x_lock_count()

◆ rw_lock_lock_word_decr()

◆ rw_lock_lock_word_incr()

◆ rw_lock_remove_debug_info()

◆ rw_lock_reset_waiter_flag()

◆ rw_lock_s_lock_func()

◆ rw_lock_s_lock_low()

◆ rw_lock_s_lock_spin()

◆ rw_lock_s_unlock_func()

◆ rw_lock_set_waiter_flag()

◆ rw_lock_set_writer_id_and_recursion_flag()

◆ rw_lock_sx_unlock_func()

◆ rw_lock_x_lock_func_nowait()

◆ rw_lock_x_unlock_func()