I'm running Gentoo Hardened AMD64 using kernel 4.3.3-hardened-r4. After keeping the Bitcoin Core 0.10.1.0 client opened for about 5 hours, Linux eats a lot of RAM. I know for one that Bitcoin Core is pretty memory-intensive so I thought closing it would free my memory, but it didn't. This is not due to filesystem cache, kernel-managed buffers and stuff; every single tool I've used that does account for that kind of "taken but free" memory shows my entire RAM as claimed by a process.
After closing it, Linux keeps eating almost 3 GB of RAM with hardly any process opened except for X, uxterm, my window manager, GKrellM, basic system services like cron, DHCP or wpa_supplicant, a bunch of BASH shells, and hardly more than 600 KB saved to tmpfs filesystems.
If I keep Bitcoin Core running for about 8-12 hours, my system just runs out of memory and throws a kernel panic.
A manually compiled and installed instance of Bitcoin Core 0.12 still presents the same issue.
As you can see here, I have hardly any processes opened save for Firefox, X, GKrellm, my window manager (wmaker) and some BASH sessions:
http://i.stack.imgur.com/uGUOk.pngAny idea of where is my free memory going?
Update: Right now, after closing the Bitcoin Core client and still staying with 2 GB of taken RAM, a few minutes later my RAM usage suddenly went back to normal. What I did in the meantime was issuing
emerge -aNDu --with-bdeps=y @world after globally enabling
USE="X" on make.conf, opening a
screen session as ROOT and starting nmon, htop and iotop, and cleaning up remnants of a failed Chromium build on /var/tmp/portage. Based on these actions I'll attempt to reproduce what made my system suddenly release all that taken RAM.