mariadb/storage/xtradb/include/mem0pool.h

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

Copyright (c) 1994, 2009, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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

/**************************************************//**
@file include/mem0pool.h
The lowest-level memory management

Created 6/9/1994 Heikki Tuuri
*******************************************************/

#ifndef mem0pool_h
#define mem0pool_h

#include "univ.i"
#include "os0file.h"
#include "ut0lst.h"

/** Memory pool */
struct mem_pool_t;

/** The common memory pool */
extern mem_pool_t*	mem_comm_pool;

/** Memory area header */
struct mem_area_t{
	ulint		size_and_free;	/*!< memory area size is obtained by
					anding with ~MEM_AREA_FREE; area in
					a free list if ANDing with
					MEM_AREA_FREE results in nonzero */
	UT_LIST_NODE_T(mem_area_t)
			free_list;	/*!< free list node */
};

/** Each memory area takes this many extra bytes for control information */
#define MEM_AREA_EXTRA_SIZE	(ut_calc_align(sizeof(struct mem_area_t),\
			UNIV_MEM_ALIGNMENT))

/********************************************************************//**
Creates a memory pool.
@return	memory pool */
UNIV_INTERN
mem_pool_t*
mem_pool_create(
/*============*/
	ulint	size);	/*!< in: pool size in bytes */
/********************************************************************//**
Frees a memory pool. */
UNIV_INTERN
void
mem_pool_free(
/*==========*/
	mem_pool_t*	pool);	/*!< in, own: memory pool */
/********************************************************************//**
Allocates memory from a pool. NOTE: This low-level function should only be
used in mem0mem.*!
@return	own: allocated memory buffer */
UNIV_INTERN
void*
mem_area_alloc(
/*===========*/
	ulint*		psize,	/*!< in: requested size in bytes; for optimum
				space usage, the size should be a power of 2
				minus MEM_AREA_EXTRA_SIZE;
				out: allocated size in bytes (greater than
				or equal to the requested size) */
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Frees memory to a pool. */
UNIV_INTERN
void
mem_area_free(
/*==========*/
	void*		ptr,	/*!< in, own: pointer to allocated memory
				buffer */
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Returns the amount of reserved memory.
@return	reserved mmeory in bytes */
UNIV_INTERN
ulint
mem_pool_get_reserved(
/*==================*/
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Validates a memory pool.
@return	TRUE if ok */
UNIV_INTERN
ibool
mem_pool_validate(
/*==============*/
	mem_pool_t*	pool);	/*!< in: memory pool */
/********************************************************************//**
Prints info of a memory pool. */
UNIV_INTERN
void
mem_pool_print_info(
/*================*/
	FILE*		outfile,/*!< in: output file to write to */
	mem_pool_t*	pool);	/*!< in: memory pool */


#ifndef UNIV_NONINL
#include "mem0pool.ic"
#endif

#endif