[openib-general] Re: RDMA memory registration

[Roland Dreier]

    Bill> I'm very confused at this point. Can you briefly explain how
    Bill> this works, or point me to a description? I don't see how
    Bill> you could do user level I/O without registering the memory
    Bill> with the hardware. I'm especially confused by the comment
    Bill> (may not have been yours) that the memory doesn't have to be
    Bill> pinned.  -- Bill Jordan InfiniCon Systems

You add a hook to the kernel so it tells you if a page is about to be
paged out or otherwise move.  Then you set a bit in the adapter's page
table so that it won't try to access that page without telling you.
If the adapter asks for the page, you get the kernel to fault the page
in and program the new physical mapping in the adapter.

 - R.