Re: OOM when adding ipv6 route: How to make available more per-cpu memory?

[Ben Greear <greearb@candelatech.com>]

On 11/08/2010 03:02 AM, Eric Dumazet wrote:
> Le samedi 06 novembre 2010 à 10:08 -0700, Ben Greear a écrit :
>
>> At least I don't see any percpu dumps in dmesg.  I vaguely remember
>> someone posting some ipv6 address scalability patches some time back.
>> I think they had to hack on /proc fs as well.  I'll see if I can
>> dig those up.
>>
>>> Make sure udev / hotplug is not the problem, if you create your devices
>>> very fast.
>>
>> We can create the macvlans w/out problem, though I'm sure that could
>> be sped up.  The problem is when we try to add IPv6 addresses to
>> them.
>
> I see. Did you check /proc/sys/net/ipv6/ tunables ?
>
> For example, I bet you need to make route/max_size a bigger value than
> default (4096)

I'm having a hard time figuring out how this actually causes something
to fail.

It seems that having max_size too small would cause the garbage collector
logic to happen more often, but I don't see any place it actually
removes or limits entries, and I can't find any other references to
ip6_rt_max_size.

I must just be missing something..so if you have any ideas where to
look, I'd love to hear it!

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com