usr/src/sys/sys/map.h

/*      map.h   4.6     81/05/12        */

/*
 * Resource Allocation Maps.
 *
 * Associated routines manage sub-allocation of an address space using
 * an array of segment descriptors.  The first element of this array
 * is a map structure, describing the arrays extent and the name
 * of the controlled object.  Each additional structure represents
 * a free segment of the address space.
 *
 * A call to rminit initializes a resource map and may also be used
 * to free some address space for the map.  Subsequent calls to rmalloc
 * and rmfree allocate and free space in the resource map.  If the resource
 * map becomes too fragmented to be described in the available space,
 * then some of the resource is discarded.  This may lead to critical
 * shortages, but is better than not checking (as the previous versions
 * of these routines did) or giving up and calling panic().  The routines
 * could use linked lists and call a memory allocator when they run
 * out of space, but that would not solve the out of space problem when
 * called at interrupt time.
 *
 * N.B.: The address 0 in the resource address space is not available
 * as it is used internally by the resource map routines.
 */
struct map {
        struct  mapent *m_limit;        /* address of last slot in map */
        char    *m_name;                /* name of resource */
/* we use m_name when the map overflows, in warning messages */
};
struct mapent
{
        int     m_size;         /* size of this segment of the map */
        int     m_addr;         /* resource-space addr of start of segment */
};

#ifdef KERNEL
struct  map *swapmap;
int     nswapmap;
struct  map *argmap;
#define ARGMAPSIZE      16
struct  map *kernelmap;
#ifdef BBNNET
struct  map *netmap;
#endif
#endif