Most things seem to function fine without /dev/shm, but it is expected
to be there (quoting linux/Documentation/filesystems/tmpfs.txt:
glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for POSIX
shared memory (shm_open, shm_unlink)).
Since /tmp/ is already mounted as tmpfs, it would be enough to mkdir
/tmp/shm and chmod it. Mounting it separately has the advantage that
it can be easily remounted to change the quota.
Zbigniew Jędrzejewski-Szmek
ede89845a4