[unix-history] / usr / src / sys / sys / map.h

/*-
* Copyright (c) 1982, 1986, The Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*
*      @(#)map.h       7.5 (Berkeley) %G%
*/

/*
* 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, for messages */
};

struct mapent {
       int     m_size;                 /* size of this segment of the map */
       int     m_addr;                 /* start of segment */
};

#ifdef KERNEL
#define ARGMAPSIZE      16
struct  map *kmemmap, *mbmap, *swapmap;
int     nswapmap;
#endif