[CentOS] Starting emacs gives "shmget failed: error 28" message

Thu Sep 3 01:04:38 UTC 2015
Robert Nichols <rnicholsNOSPAM at comcast.net>

In CentOS 6.7, if I start emacs from a terminal session, I always see
a message, "(emacs:{PID}): Gdk-WARNING **: shmget failed: error 28 (No 
space left on device)"

The message is also logged to .xsession-errors, and that occurs
regardless of how emacs is started. The same thing occurs with
SELinux in permissive mode.

Emacs version is emacs-23.1-28.el6.x86_64 .

Output from strace shows:
    shmget(IPC_PRIVATE, 393216, IPC_CREAT|0600) = -1 ENOSPC (No space 
left on device)

/proc/mounts contains:
    tmpfs /dev/shm tmpfs rw,seclabel,relatime 0 0

and "df /dev/shm" shows:
    Filesystem     1K-blocks  Used Available Use% Mounted on
    tmpfs            8194164   172   8193992   1% /dev/shm

I can't identify any behavior problems that I can relate to this,
but it seems that something is wrong.  Any clues as to what?

Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.