[tor-relays] Out of memory message

[Roger Dingledine]

On Sun, Dec 07, 2014 at 09:52:47AM +0100, Logforme wrote:
> I run the relay Logforme (855BC2DABE24C861CD887DB9B2E950424B49FC3).
> Yesterday I saw new messages in the log file:
> Dec 06 09:28:13.000 [notice] We're low on memory.  Killing circuits with
> over-long queues. (This behavior is controlled by MaxMemInQueues.)
> Dec 06 09:28:16.000 [notice] Removed 1040388096 bytes by killing 1
> circuits; 14631 circuits remain alive.
> 
> Do I read that correctly as one circuit using 1GB of memory?

Wow! Never thought I'd see that in practice.

>  The relay and the
> box is so far working fine, I just wonder if this is some kind of attack
> or if anything is wrong and if there is anything I should do about it.

Actually what you're seeing is a defense to an attack: Rob explains it
well at
https://blog.torproject.org/blog/new-tor-denial-service-attacks-and-defenses

Of course, it's also possible that this behavior occurred naturally
in some way.

Has anybody else here seen messages like this?

--Roger