sync0arr.h File Reference

#include "univ.i"
#include "ut0lst.h"
#include "ut0mem.h"
#include "os0thread.h"
#include "sync0arr.ic"

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Functions
UNIV_INLINE sync_array_t *	sync_array_get_and_reserve_cell (void *object, ulint type, const char *file, ulint line, ulint *index)
UNIV_INTERN bool	sync_array_reserve_cell (sync_array_t *arr, void *object, ulint type, const char *file, ulint line, ulint *index)
UNIV_INTERN void	sync_array_wait_event (sync_array_t *arr, ulint index)
UNIV_INTERN void	sync_array_free_cell (sync_array_t *arr, ulint index)
UNIV_INTERN void	sync_array_object_signalled (void)
UNIV_INTERN void	sync_arr_wake_threads_if_sema_free (void)
UNIV_INTERN ibool	sync_array_print_long_waits (os_thread_id_t *waiter, const void **sema))
UNIV_INTERN void	sync_array_validate (sync_array_t *arr)
UNIV_INTERN void	sync_array_print (FILE *file)
UNIV_INTERN void	sync_array_init (ulint n_threads)
UNIV_INTERN void	sync_array_close (void)
UNIV_INTERN sync_array_t *	sync_array_get (void)

Detailed Description

The wait array used in synchronization primitives

Created 9/5/1995 Heikki Tuuri

Function Documentation

UNIV_INTERN void sync_arr_wake_threads_if_sema_free

(

void

)

If the wakeup algorithm does not work perfectly at semaphore relases, this function will do the waking (see the comment in mutex_exit). This function should be called about every 1 second in the server.

UNIV_INTERN void sync_array_close

(

void

)

Close sync array wait sub-system.

UNIV_INTERN void sync_array_free_cell	(	sync_array_t *	arr,
		ulint	index
	)

Frees the cell. NOTE! sync_array_wait_event frees the cell automatically! in: index of the cell in array

Parameters

arr	in: wait array

UNIV_INTERN sync_array_t* sync_array_get

(

void

)

Get an instance of the sync wait array.

UNIV_INLINE sync_array_t* sync_array_get_and_reserve_cell	(	void *	object,
		ulint	type,
		const char *	file,
		ulint	line,
		ulint *	index
	)

Get an instance of the sync wait array and reserve a wait array cell in the instance for waiting for an object. The event of the cell is reset to nonsignalled state. If reserving cell of the instance fails, try to get another new instance until we can reserve an empty cell of it.

Returns

the instance found, never NULL. out: index of the reserved cell

Get an instance of the sync wait array and reserve a wait array cell in the instance for waiting for an object. The event of the cell is reset to nonsignalled state. If reserving cell of the instance fails, try to get another new instance until we can reserve an empty cell of it.

Returns

the instance found, never NULL.

Parameters

object	in: pointer to the object to wait for
type	in: lock request type
file	in: file where requested
line	in: line where requested
index	out: index of the reserved cell

UNIV_INTERN void sync_array_init

(

ulint

n_threads

)

Create the primary system wait array(s), they are protected by an OS mutex in: Number of slots to create

UNIV_INTERN void sync_array_object_signalled

(

void

)

Note that one of the wait objects was signalled.

UNIV_INTERN void sync_array_print

(

FILE *

file

)

Prints info of the wait array. in: file where to print

UNIV_INTERN ibool sync_array_print_long_waits	(	os_thread_id_t *	waiter,
		const void **	sema
	)

Prints warnings of long semaphore waits to stderr.

Returns

TRUE if fatal semaphore wait threshold was exceeded

Parameters

waiter	out: longest waiting thread
sema	out: longest-waited-for semaphore

UNIV_INTERN bool sync_array_reserve_cell	(	sync_array_t *	arr,
		void *	object,
		ulint	type,
		const char *	file,
		ulint	line,
		ulint *	index
	)

Reserves a wait array cell for waiting for an object. The event of the cell is reset to nonsignalled state.

Returns

true if free cell is found, otherwise false out: index of the reserved cell

Parameters

arr	in: wait array
object	in: pointer to the object to wait for
type	in: lock request type
file	in: file where requested
line	in: line where requested

UNIV_INTERN void sync_array_validate

(

sync_array_t *

arr

)

Validates the integrity of the wait array. Checks that the number of reserved cells equals the count variable. in: sync wait array

UNIV_INTERN void sync_array_wait_event	(	sync_array_t *	arr,
		ulint	index
	)

This function should be called when a thread starts to wait on a wait array cell. In the debug version this function checks if the wait for a semaphore will result in a deadlock, in which case prints info and asserts. in: index of the reserved cell

Parameters

arr	in: wait array