What's the best way to memory map a file on the roku HD1000?

Hello,
	I'm using an index file on a roku app I've written.  Currently, I just 
read the whole file into memory.  But I am concerned that I will use up all 
of the system memory.  Is there any way to use memmap on the Roku without 
using swapon?  Assuming I open the file as read only, and then memmap it to 
local memory.  The OS should be able to swap out (i.e discard and re-read) 
unused memory.

-Techtom