[openib-general] fmr vs. mr?

[Roland Dreier]

>>>>> "Joe" == Joe Damato <damato at psc.edu> writes:

    Joe> I am attempting to port some code from gen1 to gen2, has fmr
    Joe> been deprecated? What -is- fmr and how does it differ from a
    Joe> mr? If I am correct the type struct ib_mr has become struct
    Joe> ibv_mr...

FMRs are "fast" memory regions, where the memory mapping is written
directly into the HCA's context, rather than through a firmware
command interface.  This means that FMRs are faster but are limited to
a small list of physical buffers of the same side.

Are you porting userspace code or kernel code?  FMRs are only
available to kernel space, since userspace cannot be trusted to write
addresses directly into the HCA's contet.

If you post the section of code you're stuck on, we can probably help
you port it.

 - R.