include/common/memory.h

/*
 * include/common/memory.h
 * Memory management definitions..
 *
 * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, version 2.1
 * exclusively.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef _COMMON_MEMORY_H
#define _COMMON_MEMORY_H

#include <stdlib.h>

#include <common/config.h>
#include <common/mini-clist.h>

#define MEM_F_SHARED	0x1

struct pool_head {
	void **free_list;
	struct list list;	/* list of all known pools */
	unsigned int used;	/* how many chunks are currently in use */
	unsigned int allocated;	/* how many chunks have been allocated */
	unsigned int limit;	/* hard limit on the number of chunks */
	unsigned int minavail;	/* how many chunks are expected to be used */
	unsigned int size;	/* chunk size */
	unsigned int flags;	/* MEM_F_* */
	unsigned int users;	/* number of pools sharing this zone */
	char name[12];		/* name of the pool */
};

/* poison each newly allocated area with this byte if not null */
extern char mem_poison_byte;

/*
 * This function destroys a pull by freeing it completely.
 * This should be called only under extreme circumstances.
 */
static inline void pool_destroy(void **pool)
{
	void *temp, *next;
	next = pool;
	while (next) {
		temp = next;
		next = *(void **)temp;
		free(temp);
	}
}

/* Allocate a new entry for pool <pool>, and return it for immediate use.
 * NULL is returned if no memory is available for a new creation.
 */
void *pool_refill_alloc(struct pool_head *pool);

/* Try to find an existing shared pool with the same characteristics and
 * returns it, otherwise creates this one. NULL is returned if no memory
 * is available for a new creation.
 */
struct pool_head *create_pool(char *name, unsigned int size, unsigned int flags);

/* Dump statistics on pools usage.
 */
void dump_pools_to_trash();
void dump_pools(void);

/*
 * This function frees whatever can be freed in pool <pool>.
 */
void pool_flush2(struct pool_head *pool);

/*
 * This function frees whatever can be freed in all pools, but respecting
 * the minimum thresholds imposed by owners.
 */
void pool_gc2();

/*
 * This function destroys a pull by freeing it completely.
 * This should be called only under extreme circumstances.
 */
void *pool_destroy2(struct pool_head *pool);

/*
 * Returns a pointer to type <type> taken from the
 * pool <pool_type> or dynamically allocated. In the
 * first case, <pool_type> is updated to point to the
 * next element in the list.
 */
#define pool_alloc2(pool)                                       \
({                                                              \
        void *__p;                                              \
        if ((__p = (pool)->free_list) == NULL)			\
                __p = pool_refill_alloc(pool);                  \
        else {                                                  \
                (pool)->free_list = *(void **)(pool)->free_list;\
		(pool)->used++;					\
		if (unlikely(mem_poison_byte))			\
			memset(__p, mem_poison_byte, (pool)->size);	\
        }                                                       \
        __p;                                                    \
})

/*
 * Puts a memory area back to the corresponding pool.
 * Items are chained directly through a pointer that
 * is written in the beginning of the memory area, so
 * there's no need for any carrier cell. This implies
 * that each memory area is at least as big as one
 * pointer. Just like with the libc's free(), nothing
 * is done if <ptr> is NULL.
 */
#define pool_free2(pool, ptr)                           \
({                                                      \
        if (likely((ptr) != NULL)) {                    \
                *(void **)(ptr) = (void *)(pool)->free_list;	\
                (pool)->free_list = (void *)(ptr);	\
                (pool)->used--;				\
        }                                               \
})


#endif /* _COMMON_MEMORY_H */

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */