[ofa-general] max_mr limit

[Or Gerlitz]

Rajouri Jammu wrote:
> Does that mean that no matter how I size my memory regions the maximum 
> amount of (total) memory I can register is = 2^20 * 4K = 4GB?
> I.e., Am I limited by the total number of MTTs?
Generally speaking, yes, the IB network MMU (MTT this case) is limited 
in the number of slots it has and so in the amount of memory it can map 
at once, but I assume this is typical eg for I/O MMUs and makes sense.

However, each slot can map --more-- then 4K, so one should be able to 
use huge-pages etc. I am not sure what is the actual status of 
registering huge-pages by the Linux IB stack, maybe Roland can comment 
on that.

Or.