nf_conntrack: table full .. leads to reboot

[Pietro Paolini]

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.