mariadb/storage/innobase/include/sync0arr.ic

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/**************************************************//**
@file include/sync0arr.ic
The wait array for synchronization primitives

Inline code

Created 9/5/1995 Heikki Tuuri
*******************************************************/

extern ulint		sync_array_size;
extern sync_array_t**	sync_wait_array;

#include "ut0counter.h"

/**********************************************************************//**
Get an instance of the sync wait array.
@return an instance of the sync wait array. */

UNIV_INLINE
sync_array_t*
sync_array_get()
/*============*/
{
	if (sync_array_size <= 1) {
		return(sync_wait_array[0]);
	}

	return(sync_wait_array[default_indexer_t<>::get_rnd_index()
			       % sync_array_size]);
}

/******************************************************************//**
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.
@return the sync array reserved, never NULL. */
UNIV_INLINE
sync_array_t*
sync_array_get_and_reserve_cell(
/*============================*/
	void*		object, /*!< in: pointer to the object to wait for */
	ulint		type,	/*!< in: lock request type */
	const char*	file,	/*!< in: file where requested */
	unsigned	line,	/*!< in: line where requested */
	sync_cell_t**	cell)	/*!< out: the cell reserved, never NULL */
{
	sync_array_t*	sync_arr = NULL;

	*cell = NULL;
	for (ulint i = 0; i < sync_array_size && *cell == NULL; ++i) {
		/* Although the sync_array is get in a random way currently,
		we still try at most sync_array_size times, in case any
		of the sync_array we get is full */
		sync_arr = sync_array_get();
		*cell = sync_array_reserve_cell(sync_arr, object, type,
					       file, line);
        }

	/* This won't be true every time, for the loop above may execute
	more than srv_sync_array_size times to reserve a cell.
	But an assertion here makes the code more solid. */
	ut_a(*cell != NULL);

	return(sync_arr);
}