I'm using a memory-limited machine, and would like to tune the buffer
caching behavior a bit.  In particular, I'd like to limit the amount
of caching the kernel does on behalf of xmms, since I'm more likely to
play the next song than the previous.  But I don't want to slow down
the system on pkgsrc builds, etc., that really benefit from the buffer
cache.

Is there a way to give the system hints about how to limit the cache
on a per-program or per-filesystem basis?  Or even better, to hint
that a particular program or filesystem tends not to exhibit an MRU
file access pattern?

  Alan