Not sure where to begin so here goes anway. Today I did an rsync backup
of a server with 2million+ files. Before doing so the used memory on the
server this was initiated from was under 200meg (excluding buffers and
cache). During the rsync the memory used grew to just shy of 1.6gig and
now, about 2 hours after the rsync has well and truly finished, the used
memory is at 1.23gig. This is what free reports:

             total       used       free     shared    buffers cached
Mem:       2058128    1994468      63660          0     688604 11432
-/+ buffers/cache:    1294432     763696
Swap:      1048568          0    1048568

There are 75 processes on the box of which almost 47 are kernel
processes + init. Of the rest, the top 3 have an RSS of 9.4meg, 6.2meg
and 4.8meg, 7 are at around 2meg and the rest are below 2meg with the
majority below 1. So unless I'm misunderstanding something, processess
alone do not account for the amount of used memory.

The destination of the rsync was an ext3 filesystem over raid5 over ahci
sata.

I've included /proc/meminfo, /proc/slabinfo and config.gz. If there's
anything else please shout.

-- 
    "To the extent that we overreact, we proffer the terrorists the
    greatest tribute."
    	- High Court Judge Michael Kirby