Free memory exhausted by networking

[RW]

On Wed, 14 Dec 2011 00:57:52 +0700
Dmitriy Kryuk wrote:

> I'm running Transmission (http://www.transmissionbt.com/), а
> BitTorrent client on my FreeBSD 7.2 box. It requests large recieve
> buffers for its network connections. This leaves my system with
> absolutely no free memory. If some process frees a large amount of
> memory, it gets consumed about 1.5 megabytes per second until it
> drops to zero. I don't seem to have any problems like denied network
> connections or memory allocation, but it makes my system swap in and
> out often. As top shows:
> 
> CPU: 24.9% user, 0.0% nice, 27.2% system, 33.1% interrupt, 14.8% idle
> Mem: 217M Active, 143M Inact, 105M Wired, 25M Cache, 59M Buf, 8K Free
> Swap: 4352M Total, 236K Used, 4352M Free

Swapping doesn't have much to do with low free memory.

There's actually very little swap use, but only 2 pages of free memory.
I think that means that the memory is being used for interrupt
handling, because anything else would allocate from the cache queue
well before that happened. 

You might try switching the interface to polling or increasing both of
the free memory watermarks vm.v_free_min and vm.v_free_target.