Size of on-chip memory

Hello all,

Can someone please explain how the Nios On-Chip memory component is constructed of the device's RAM blocks ? Can it reside in only one type of blocks, i.e. M-RAMs ?

My problem is that although the EP2S30 device seemingly has lots of memory (1.3 mln bits), I don't manage squeezing more than 72Kbyte of On-chip memory into it - the Quartus fitter says it's impossible.

What is the solution ?

Thanks in advance