On Monday 17 March 2008 09:22, Or Gerlitz wrote: > 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.
In Mellanox HCAs, each memory region (i.e., mpt) can specify how many pages each mtt entry it uses represents. This would allow a much larger number of large regions to be mapped (essentially eliminating the current limitation). Currently, this feature is not supported by the driver code. - Jack > > > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
