/* * Copyright (c) 1982, 1986 Regents of the University of California. * All rights reserved. The Berkeley software License Agreement * specifies the terms and conditions for redistribution. * * @(#)map.h 7.1 (Berkeley) 6/4/86 */ /* * 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; struct map *mbmap; #endif