On Tue, Apr 25, 2006 at 04:38:02PM -0400, Greg Troxel wrote: > NetBSD says to use MAP_FAILED, and to include sys/mman.h, which > contains: > > #define MAP_FAILED ((void *) -1) /* mmap() failed */
Strange that is exactly what we use. The only place that mmaps in rwcdb is rwcdb_file.c:file_mread. And that file includes <sys/mman.h> and even defines MAP_FAILED the same way if it happens to be missing. Then the mmap return is checked against MAP_FAILED in which case we set f->map to NULL to make us fall back on the 'read into allocated memory buffer' code. I actually wonder how much the mmap buys us here, we clearly have the potential for unaligned accesses and solving that will require the extra memory copy. Reading into the pre-allocated buffer will always be aligned. Also the pdb database is really only accessed when a new RPC2 connection is set up. We get the sorted list of all groups a user is a member of at that time and associate the list with the connection. After that when we need to check a directory ACL it is compared against the cached list. Jan
