tmpfs != /dev/shm (was Re: noexec on /dev/shm)

On Tue, Dec 14, 2010 at 10:19:38PM -0800, John Reiser wrote:

Also, the claim "The API for /dev/shm is shm_open()" is incorrect. See the other message for the history. When something is in the file system, then by default the file system APIs (including creat, open, read, write, close, execve, dlopen, ...) are legitimate uses. (Originally [System V] shared memory was *not* in the file system, and this caused problems.)

I think you're confusing two things here. POSIX shared memory objects are implemented on Linux using a tmpfs filesystem mounted at /dev/shm.

I don't think there's a particularly good reason to use that filesystem for other uses. Just mount another tmpfs elsewhere.