Docker instructions would be good.

But how can a build need more than 2GB of memory??

Complex C/C++ projects can need lots of memory at final link, especially if they're using WPO/SCU or aggressive optimisation levels.

w/ Docker, the article would be reduced to 'so we started passing in `-m` to our `docker run` command.

there is a certain amount of overhead from Codeship, it's around 200-300M. the memory usage also includes all running services inside the build (eg. Postgres, MySQL, etc.)

i think most developer don't optimize their tests for minimal memory usage. we observed that C/C++/Java projects consume a bigger amount of memory during the compilation step.

An example: webkitgtk requires (IIRC) 16GB of memory for the final link step if you turn on debugging.