[lobster_johnson]

The problem is that if you disable swap completely and let the system refuse allocation, you will face failures not just from the process that was responsible for taking most of the memory, but from existing ones that attempt to continue operating normally -- including innocuous processes such as bash and sshd.

This would affect C programs in particular, since they usually manage their memory manually. If bash can't malloc() a buffer for its input, for example, it will simply fail, and you might be able to do anything to fix the system; the same goes for sshd, which might end up refusing new connections as a result. Programs that preallocate important data structures, and programs using garbage collection, would fare somewhat better.

In other words, if swap is disabled you will still need a sort of soft limit or reserved space to ensure that programs can survive memory starvation. I don't know if the Linux kernel (or the GNU C library) has anything of the sort.