Daniel A. Ramaley wrote:
I have not seen documented how mfs allocates memory, so i just did a quick test. On a machine with 205 MB of RAM free i mounted a 128 MB mfs. Free RAM dropped to 199 MB; only 6 MB used! So OpenBSD must only allocate RAM for sectors that have actually been written to. Since the system is not using any more RAM than it has to, i think i'll switch to using mfs for /tmp as well.
mount_mfs uses mmap(), which in turn will only use those pages which the program actually touches. An unused (large) mfs will not take up much ram, and if it does, it can swap out seldom used pages too.
