nf_conntrack: table full

From: Pietro Paolini
Date: Tue Apr 01 2014 - 16:42:04 EST


Hello,
I am doing some investigation regarding an error I am experiencing using my linux embedded device as router in my home network.

If I try to push the number the connections to around 20K I will se a lot of messages from the kernel saying :

nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.
nf_conntrack: table full, dropping packet.

Actually this is fine for me since the number of allowed conntrack is /proc/sys/net/netfilter/nf_conntrack_max is around 7844, the
strange thing is that the device will reboot after a while - actually my watchdog reboots the device since is not able to allocate memory -
I have a try with slabtop running and I have seen that but monitoring the /proc/slabinfo:
3968 nf_conntrack_c0d4eacc
4392 size-8192
6360 skbuff_head_cache
15356 size-4096
31808 size-1024

Well size-1024 is quite high, do you know where is that from and how is that related to the packets coming in ? Even point me at the right
folder in the source code could be great since I am really lost here.

Thanks in advance,
Pietro.

"And therefore never send to know for whom the bell tolls"
pulsarpietro@xxxxxxx
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