[cesarb]

The problem with allocation failure is that it's non-local. Suppose thread A does a huge allocation of several hundred megabytes. The best case scenario is that this allocation fails cleanly; the worst case scenario is that this allocation succeeds but causes a small 1024-byte allocation in an unrelated thread B to fail (and it doesn't have to be multiple threads, this can happen even within a single thread). I don't know of any solution for this problem, other than statically reserving the memory which will be used for each part of the system.

[a1369209993]

The horrible part is that this isn't even limited to threads; a competely separate process (even, eg, a browser JS engine running 'completely' untrusted remote code) can cause your program to hit a allocation failure, and then not have enough memory to preform nontrivial error-handling.