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

[Matthew Miller]

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.


-- 
Matthew Miller <mattdm at mattdm.org>
Senior Systems Architect -- Instructional & Research Computing Services
Harvard School of Engineering & Applied Sciences