[bouncycastle]

sometimes swap seems to accumulate even though there is plenty of ram. It is too "greedy" by default, probably set for desktops not servers in mind.

Therefore it is better to always tune "vm.swappiness" to 1 in /etc/sysctl.conf

You can also configure your web server / TCP stack buffers / file limits so they never allocate memory over the physical ram available. (eg. in nginx you can setup worker/connection limits and buffer sizes.)