mariadb/storage/innobase/ha/hash0hash.cc

/*****************************************************************************

Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file ha/hash0hash.cc
The simple hash table utility

Created 5/20/1997 Heikki Tuuri
*******************************************************/

#include "hash0hash.h"
#include "mem0mem.h"
#include "sync0sync.h"

/************************************************************//**
Reserves all the locks of a hash table, in an ascending order. */
void
hash_lock_x_all(
/*============*/
	hash_table_t*	table)	/*!< in: hash table */
{
	ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

	for (ulint i = 0; i < table->n_sync_obj; i++) {

		rw_lock_t* lock = table->sync_obj.rw_locks + i;

		ut_ad(!rw_lock_own(lock, RW_LOCK_S));
		ut_ad(!rw_lock_own(lock, RW_LOCK_X));

		rw_lock_x_lock(lock);
	}
}

/************************************************************//**
Releases all the locks of a hash table, in an ascending order. */
void
hash_unlock_x_all(
/*==============*/
	hash_table_t*	table)	/*!< in: hash table */
{
	ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

	for (ulint i = 0; i < table->n_sync_obj; i++) {

		rw_lock_t* lock = table->sync_obj.rw_locks + i;

		ut_ad(rw_lock_own(lock, RW_LOCK_X));

		rw_lock_x_unlock(lock);
	}
}

/************************************************************//**
Releases all but passed in lock of a hash table, */
void
hash_unlock_x_all_but(
/*==================*/
	hash_table_t*	table,		/*!< in: hash table */
	rw_lock_t*	keep_lock)	/*!< in: lock to keep */
{
	ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);

	for (ulint i = 0; i < table->n_sync_obj; i++) {

		rw_lock_t* lock = table->sync_obj.rw_locks + i;

		ut_ad(rw_lock_own(lock, RW_LOCK_X));

		if (keep_lock != lock) {
			rw_lock_x_unlock(lock);
		}
	}
}

/*************************************************************//**
Creates a hash table with >= n array cells. The actual number of cells is
chosen to be a prime number slightly bigger than n.
@return own: created table */
hash_table_t*
hash_create(
/*========*/
	ulint	n)	/*!< in: number of array cells */
{
	hash_cell_t*	array;
	ulint		prime;
	hash_table_t*	table;

	prime = ut_find_prime(n);

	table = static_cast<hash_table_t*>(
		ut_malloc_nokey(sizeof(hash_table_t)));

	array = static_cast<hash_cell_t*>(
		ut_malloc_nokey(sizeof(hash_cell_t) * prime));

	/* The default type of hash_table is HASH_TABLE_SYNC_NONE i.e.:
	the caller is responsible for access control to the table. */
	table->type = HASH_TABLE_SYNC_NONE;
	table->array = array;
	table->n_cells = prime;
#ifdef BTR_CUR_HASH_ADAPT
# if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
	table->adaptive = FALSE;
# endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
#endif /* BTR_CUR_HASH_ADAPT */
	table->n_sync_obj = 0;
	table->sync_obj.mutexes = NULL;
	table->heaps = NULL;
	table->heap = NULL;
	ut_d(table->magic_n = HASH_TABLE_MAGIC_N);

	/* Initialize the cell array */
	hash_table_clear(table);

	return(table);
}

/*************************************************************//**
Frees a hash table. */
void
hash_table_free(
/*============*/
	hash_table_t*	table)	/*!< in, own: hash table */
{
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

	ut_free(table->array);
	ut_free(table);
}

/*************************************************************//**
Creates a sync object array to protect a hash table.
::sync_obj can be mutexes or rw_locks depening on the type of
hash table. */
void
hash_create_sync_obj(
/*=================*/
	hash_table_t*		table,	/*!< in: hash table */
	enum hash_table_sync_t	type,	/*!< in: HASH_TABLE_SYNC_MUTEX
					or HASH_TABLE_SYNC_RW_LOCK */
	latch_id_t		id,	/*!< in: latch ID */
	ulint			n_sync_obj)/*!< in: number of sync objects,
					must be a power of 2 */
{
	ut_a(n_sync_obj > 0);
	ut_a(ut_is_2pow(n_sync_obj));
	ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

	table->type = type;

	switch (table->type) {
	case HASH_TABLE_SYNC_MUTEX:
		table->sync_obj.mutexes = static_cast<ib_mutex_t*>(
			ut_malloc_nokey(n_sync_obj * sizeof(ib_mutex_t)));

		for (ulint i = 0; i < n_sync_obj; i++) {
			mutex_create(id, table->sync_obj.mutexes + i);
		}

		break;

	case HASH_TABLE_SYNC_RW_LOCK: {

		latch_level_t	level = sync_latch_get_level(id);

		ut_a(level != SYNC_UNKNOWN);

		table->sync_obj.rw_locks = static_cast<rw_lock_t*>(
			ut_malloc_nokey(n_sync_obj * sizeof(rw_lock_t)));

		for (ulint i = 0; i < n_sync_obj; i++) {
			rw_lock_create(hash_table_locks_key,
			     table->sync_obj.rw_locks + i, level);
		}

		break;
	}

	case HASH_TABLE_SYNC_NONE:
		ut_error;
	}

	table->n_sync_obj = n_sync_obj;
}