| 1 | /* map.h 4.5 81/02/28 */ |
| 2 | |
| 3 | /* |
| 4 | * Resource Allocation Maps. |
| 5 | * |
| 6 | * Associated routines manage sub-allocation of an address space using |
| 7 | * an array of segment descriptors. The first element of this array |
| 8 | * is a map structure, describing the arrays extent and the name |
| 9 | * of the controlled object. Each additional structure represents |
| 10 | * a free segment of the address space. |
| 11 | * |
| 12 | * A call to rminit initializes a resource map and may also be used |
| 13 | * to free some address space for the map. Subsequent calls to rmalloc |
| 14 | * and rmfree allocate and free space in the resource map. If the resource |
| 15 | * map becomes too fragmented to be described in the available space, |
| 16 | * then some of the resource is discarded. This may lead to critical |
| 17 | * shortages, but is better than not checking (as the previous versions |
| 18 | * of these routines did) or giving up and calling panic(). The routines |
| 19 | * could use linked lists and call a memory allocator when they run |
| 20 | * out of space, but that would not solve the out of space problem when |
| 21 | * called at interrupt time. |
| 22 | * |
| 23 | * N.B.: The address 0 in the resource address space is not available |
| 24 | * as it is used internally by the resource map routines. |
| 25 | */ |
| 26 | struct map { |
| 27 | struct mapent *m_limit; /* address of last slot in map */ |
| 28 | char *m_name; /* name of resource */ |
| 29 | /* we use m_name when the map overflows, in warning messages */ |
| 30 | }; |
| 31 | struct mapent |
| 32 | { |
| 33 | int m_size; /* size of this segment of the map */ |
| 34 | int m_addr; /* resource-space addr of start of segment */ |
| 35 | }; |
| 36 | |
| 37 | #ifdef KERNEL |
| 38 | struct map *swapmap; |
| 39 | int nswapmap; |
| 40 | struct map *argmap; |
| 41 | #define ARGMAPSIZE 16 |
| 42 | struct map *kernelmap; |
| 43 | #endif |