how would you get a deadlock with non-blocking requests ?

I never said you did ?

not you per-se no.

but this whole thread started with deadlock on remote calls, and i was curious about how that could be with async calls.

Oh, I think that the mailbox access a process has can wont block unless its full, in which case the message will be dropped.

I think you can check message_queue_len using erlang:process_info/2 to find the mailbox size and simply back off, or fail noisly.