* Find a memory region that: * - is free * - sits inside the limit range * - meets the alignment requirement */
| 1225 | * - meets the alignment requirement |
| 1226 | */ |
| 1227 | static void *_find_free(rt_aspace_t aspace, void *prefer, rt_size_t req_size, |
| 1228 | void *limit_start, rt_size_t limit_size, |
| 1229 | mm_flag_t flags) |
| 1230 | { |
| 1231 | rt_varea_t varea = NULL; |
| 1232 | void *va = RT_NULL; |
| 1233 | struct _mm_range limit = {limit_start, (char *)limit_start + limit_size - 1}; |
| 1234 | |
| 1235 | rt_ubase_t align_mask = ~0ul; |
| 1236 | if (flags & MMF_REQUEST_ALIGN) |
| 1237 | { |
| 1238 | align_mask = ~((1 << MMF_GET_ALIGN(flags)) - 1); |
| 1239 | } |
| 1240 | |
| 1241 | if (flags & MMF_MAP_FIXED) |
| 1242 | { |
| 1243 | struct _mm_range range = {prefer, (char *)prefer + req_size - 1}; |
| 1244 | |
| 1245 | /* caller should guarantee that the request region is legal */ |
| 1246 | RT_ASSERT(!_not_in_range(flags, prefer, req_size, limit_start, limit_size)); |
| 1247 | |
| 1248 | varea = _aspace_bst_search_overlap(aspace, range); |
| 1249 | if (!varea) |
| 1250 | { |
| 1251 | va = prefer; |
| 1252 | } |
| 1253 | else |
| 1254 | { |
| 1255 | /* region not freed */ |
| 1256 | } |
| 1257 | } |
| 1258 | else if (prefer != RT_NULL) |
| 1259 | { |
| 1260 | struct _mm_range range; |
| 1261 | |
| 1262 | /* ceiling the prefer address */ |
| 1263 | prefer = _align(prefer, align_mask); |
| 1264 | if (_not_in_range(flags, prefer, req_size, limit_start, limit_size)) |
| 1265 | { |
| 1266 | prefer = limit_start; |
| 1267 | } |
| 1268 | |
| 1269 | range.start = prefer; |
| 1270 | range.end = (char *)prefer + req_size - 1; |
| 1271 | varea = _aspace_bst_search_overlap(aspace, range); |
| 1272 | |
| 1273 | if (!varea) |
| 1274 | { |
| 1275 | /* if preferred and free, just return the prefer region */ |
| 1276 | va = prefer; |
| 1277 | } |
| 1278 | else |
| 1279 | { |
| 1280 | /* search from `varea` in ascending order */ |
| 1281 | va = _ascending_search(varea, req_size, align_mask, limit); |
| 1282 | if (va == RT_NULL) |
| 1283 | { |
| 1284 | /* rewind to first range */ |
no test coverage detected