polardbxengine/storage/innobase/include/sync0arr.h

113 lines
4.5 KiB
C

/*****************************************************************************
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*****************************************************************************/
/** @file include/sync0arr.h
The wait array used in synchronization primitives
Created 9/5/1995 Heikki Tuuri
*******************************************************/
#ifndef sync0arr_h
#define sync0arr_h
#include "os0thread.h"
#include "univ.i"
/** Synchronization wait array cell */
struct sync_cell_t;
/** Synchronization wait array */
struct sync_array_t;
/** 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.
@param[in] object pointer to the object to wait for
@param[in] type lock request type
@param[in] file file where requested
@param[in] line line where requested
@param[out] cell the cell reserved, never NULL
@return the sync array found, never NULL. */
UNIV_INLINE
sync_array_t *sync_array_get_and_reserve_cell(void *object, ulint type,
const char *file, ulint line,
sync_cell_t **cell);
/** Reserves a wait array cell for waiting for an object.
The event of the cell is reset to nonsignalled state. */
sync_cell_t *sync_array_reserve_cell(
sync_array_t *arr, /*!< in: wait array */
void *object, /*!< in: pointer to the object to wait for */
ulint type, /*!< in: lock request type */
const char *file, /*!< in: file where requested */
ulint line); /*!< in: line where requested */
/** 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. */
void sync_array_wait_event(sync_array_t *arr, /*!< in: wait array */
sync_cell_t *&cell); /*!< in: the reserved cell */
/** Frees the cell. NOTE! sync_array_wait_event frees the cell
automatically! */
void sync_array_free_cell(sync_array_t *arr, /*!< in: wait array */
sync_cell_t *&cell); /*!< in: the reserved cell */
/** Note that one of the wait objects was signalled. */
void sync_array_object_signalled();
/** 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. */
void sync_arr_wake_threads_if_sema_free();
/** Prints warnings of long semaphore waits to stderr.
@return true if fatal semaphore wait threshold was exceeded */
ibool sync_array_print_long_waits(
os_thread_id_t *waiter, /*!< out: longest waiting thread */
const void **sema); /*!< out: longest-waited-for semaphore */
/** Prints info of the wait array. */
void sync_array_print(FILE *file); /*!< in: file where to print */
/** Create the primary system wait array(s), they are protected by an OS mutex
*/
void sync_array_init(ulint n_threads); /*!< in: Number of slots to create */
/** Close sync array wait sub-system. */
void sync_array_close();
/** Get an instance of the sync wait array. */
UNIV_INLINE
sync_array_t *sync_array_get();
#include "sync0arr.ic"
#endif /* sync0arr_h */