Linux supports overcommitted memory and so will lie to your application about memory availability. When I tested several common open-source applications in a memory-constrained environment none of them, except for the Java VM, handled OOM conditions gracefully. I came to the conclusion it's not worth the programming effort unless your application will specifically expect this condition to occur.
I work on systems that don't run on Linux, and those systems also have reasonable business requirements for graceful failure on OOM. This is unhelpful.
