Set max-conns to 0 by default, making concurrency limit opt-in
Fixes #552 (closed).
We have a connection concurrency limiter which defaults to 5000 connections. However, beyond this limit it is not very well behaved. It simply stalls new connections on accept(2) and does not explicitly reject them. There is a separate issue to improve the observability of this mechanism: #551.
However, we also would like to disable the limiter by default. I suspect we'd be fine without this on gitlab.com. We can likely handle way more connections than 5k, and will most likely saturate other resources first.
In fact, I don't believe linux has a hard limit on number of incoming connections.
Edited by Igor