I have a perplexing problem with my Macbook Pro (16GB RAM, OS X 10.8.4). If I use up all my main memory, the computer crashes. The screen freezes on whatever window it was on (not a kernel panic), and is totally unresponsive.
I have also noticed that the "wired" memory usage in Activity Monitor seems to get very high – most of my RAM usage is "wired". And even upon boot, there is a kernel_task process that uses 1.5GB + of memory which seems somewhat high. These points may or may not be relevant.
I know I have needed virtual memory in the past and had no problems, so I have no idea what is wrong. It seems as if the computer just flat-out refuses to use virtual memory – that would certainly explain the crash. In fact, my /private/var/vm/ folder does not even exist.
Best Answer
Turns out the simple solution sometimes is the proper one after all! It seems /private/var/vm/ should always exist (even if it is empty, ie on restart), so however it got deleted the answer was to just
sudo mkdir /private/var/vm/. Seemingly non-robust coding on Apple's part, but at least it's fixed. Never mind!