One of my commits has some large generated files (a few thousand lines). When viewing it on Differential, the error 'Failed to proc_open(): proc_open(): fork failed - Cannot allocate memory' was shown on the web interface.
Can anyone give some pointers?
You could try increasing your PHP memory limit to something larger than what it's set to now.
Your system might also be memory constrained and not actually have enough memory to allocate for the task. In that case you should try to add more RAM, whatever that means for your setup.