I've found (part of) the answer to my own question - the virtual memory comes from the thread stacks. Setting -t 1 reduces the virtual memory to around 20MB.
I've read from other posts that it is no longer possible to have a non- threaded memcached version. It appears on my system that the stack size being used is 10MB. This is almost certainly way too large. Is there any way to conveniently (i.e. without major edits to the source code) set the thread stack size for the threads that memcached uses, e.g. through a macro setting?
