I have a strange error on my Raspberry Pi2. System is archlinuxarm.

Short after boot (about 30 secs), the system states that it is out of memory, resulting in closing many applications, most time till a kernel panic (Out of Memory but no killable processes). Strange thing is, that I deployed a 18GB Swap partition and the problem remains ( at least it should take more time to fill it). So I used free in these 30secs to monitor.

free -mws 0.5

The result is that there is about 70M used and the rest increasingly used for cache, which is afaik the normal behavior. Then, with reaching the ~30sec, free output slows down as if the system is in high load. Swap gets filled with about 40M, leaving the rest as it is. Here I would expect, that first cache is decreasing, before swap is used. Then the system starts killing processes, so that I can't monitor the memory anymore. In the statistics, that are readable while killing it still says that swap is nearly unused.

So It seems that the kernel doesn't frees up cache as it should and neither used swap at low memory.

Does everyone knows what is happening here.

P.S. After kernel-panic, kdb is entered, but I can't do anything, because the keyboard isn't working.

Sample dmesg/log output Graph of non-constant output of /proc/meminfo: enter image description here

  • Do you have at least stack trace of the panic? – myaut Apr 3 '15 at 15:01
  • I'd also check the output of the dmesg command in case it's printing something relevant there. – Bratchley Apr 3 '15 at 15:04
  • cat /proc/meminfo is probably much more useful than the summary provided by free. Also, what's the workload that's causing this? – derobert Apr 3 '15 at 16:09
  • I added the dmesg/log output of one boot. I somhow can't reproduce the kernel panic and didn't find it in the logs. – bvolkmer Apr 4 '15 at 16:43
  • @derobert I've added a graph of the non-constant /proc/meminfo output, captured from login till oom (as the capture is also killed). I don't know what unevictable means, I can't even find a definition. Also I don't know how to figure out the workload. – bvolkmer Apr 4 '15 at 19:05

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