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/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup genericmm
 * @{
 */
/** @file
 */

#ifndef KERN_SLAB_H_
#define KERN_SLAB_H_

#include <adt/list.h>
#include <synch/spinlock.h>
#include <atomic.h>
#include <mm/frame.h>

/** Minimum size to be allocated by malloc */
#define SLAB_MIN_MALLOC_W 4

/** Maximum size to be allocated by malloc */
#define SLAB_MAX_MALLOC_W 18

/** Initial Magazine size (TODO: dynamically growing magazines) */
#define SLAB_MAG_SIZE  4

/** If object size is less, store control structure inside SLAB */
#define SLAB_INSIDE_SIZE   (PAGE_SIZE >> 3)

/** Maximum wasted space we allow for cache */
#define SLAB_MAX_BADNESS(cache)   (((unsigned int) PAGE_SIZE << (cache)->order) >> 2)

/* slab_reclaim constants */

/** Reclaim all possible memory, because we are in memory stress */
#define SLAB_RECLAIM_ALL  0x1 

/* cache_create flags */

/** Do not use per-cpu cache */
#define SLAB_CACHE_NOMAGAZINE 0x1
/** Have control structure inside SLAB */
#define SLAB_CACHE_SLINSIDE   0x2
/** We add magazine cache later, if we have this flag */
#define SLAB_CACHE_MAGDEFERRED (0x4 | SLAB_CACHE_NOMAGAZINE)

typedef struct {
    link_t link;
    count_t busy;   /**< Count of full slots in magazine */
    count_t size;   /**< Number of slots in magazine */
    void *objs[];   /**< Slots in magazine */
} slab_magazine_t;

typedef struct {
    slab_magazine_t *current;
    slab_magazine_t *last;
    SPINLOCK_DECLARE(lock);
} slab_mag_cache_t;


typedef struct {
    char *name;

    link_t link;

    /* Configuration */
    /** Size of slab position - align_up(sizeof(obj)) */
    size_t size;

    int (*constructor)(void *obj, int kmflag);
    int (*destructor)(void *obj);

    /** Flags changing behaviour of cache */
    int flags;

    /* Computed values */
    uint8_t order;              /**< Order of frames to be allocated */
    unsigned int objects;       /**< Number of objects that fit in */

    /* Statistics */
    atomic_t allocated_slabs;
    atomic_t allocated_objs;
    atomic_t cached_objs;
    /** How many magazines in magazines list */
    atomic_t magazine_counter; 

    /* Slabs */
    link_t full_slabs;  /**< List of full slabs */
    link_t partial_slabs;   /**< List of partial slabs */
    SPINLOCK_DECLARE(slablock);
    /* Magazines  */
    link_t magazines;   /**< List o full magazines */
    SPINLOCK_DECLARE(maglock);

    /** CPU cache */
    slab_mag_cache_t *mag_cache;
} slab_cache_t;

extern slab_cache_t * slab_cache_create(char *name, size_t size, size_t align,
    int (*constructor)(void *obj, int kmflag), int (*destructor)(void *obj),
    int flags);
extern void slab_cache_destroy(slab_cache_t *cache);

extern void * slab_alloc(slab_cache_t *cache, int flags);
extern void slab_free(slab_cache_t *cache, void *obj);
extern count_t slab_reclaim(int flags);

/* slab subsytem initialization */
extern void slab_cache_init(void);
extern void slab_enable_cpucache(void);

/* kconsole debug */
extern void slab_print_list(void);

/* malloc support */
extern void * malloc(unsigned int size, int flags);
extern void * realloc(void *ptr, unsigned int size, int flags);
extern void free(void *ptr);
#endif

/** @}
 */