If the player allocates a bit too much cache, this could cause pages of the player's binary to be pushed out of memory. As soon as any code-path hits one of these pages, the player will pause until the disk is spun up and the page is read back.

man mlockall

The car-player never, ever, pages out. (The Rio Central player can, but even there all the code needed to come back from sleep is mlocked.)

I even have a feeling we needed to hack the kernel to disable a sanity check on the total amount of mlocked memory.

Peter