From george_samuel on Mon, 19 Jul 1999
I find that the amount of memory free decreases after copying large files. --(I have a PII 300 with 128Mb ram kernel 2.2.10-ac10 ). the amount of free memory as shown by free becomes ~6Mb even after doing a sync and verifying that there are no dirty blocks.If I again do some copying - swap out happens and the amount of free memory decreases. The amount in buffer used increases.I read in kerneltraffic that memory allocated for caching filesystem metadata is not given back but is kept for future use --that happens only when I mount some filesystem and later unmount it.I am ignorant .Please elaborate on this
Don't worry about it.
The memory that's listed as being in use by the buffer cache can be used by applications as the kernel sees fit.
Here's my current 'free' output:
total used free shared buffers cached Mem: 63200 61488 1712 31712 3000 31236 -/+ buffers/cache: 27252 35948 Swap: 104416 0 104416
Here's a bit more info on my current state:
uptime: 4:27am up 5 days, 16:00, 9 users, load average: 0.00, 0.00, 0.00 uname -a: Linux canopus 2.2.0 #8 Fri Jan 29 19:17:29 PST 1999 i586 unknown
(The uptime is so short because I installed a new distribution on a secondary partition recently --- and I've been playing with it).
Notice that my free memory is less than 2K. That is typical. It just means that my kernel isn't using that small chunk of RAM for anything better (buffers, and caching are better uses for it).