结构体mem_pool_t

/** Memory area header */
typedef struct mem_area_struct    mem_area_t;
/** Memory pool */
typedef struct mem_pool_struct    mem_pool_t;


/** Memory area header */

struct mem_area_struct{
    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 */
};

/** Data structure for a memory pool. The space is allocated using the buddy
algorithm, where free list i contains areas of size 2 to power i. */
struct mem_pool_struct{
    byte*        buf;        /*!< memory pool */
    ulint        size;        /*!< memory common pool size */
    ulint        reserved;    /*!< amount of currently allocated
                    memory */
    mutex_t        mutex;        /*!< mutex protecting this struct */
    UT_LIST_BASE_NODE_T(mem_area_t)
            free_list[64];    /*!< lists of free memory areas: an
                    area is put to the list whose number
                    is the 2-logarithm of the area size */
};