Re: Maximum size for memory registration (ibv_reg_mr)

Eli Cohen
2010-10-07T11:49:04Z

On Thu, Oct 07, 2010 at 01:21:36PM +0200, Or Gerlitz wrote:
> I would implement it for regular pages and drop a note in the
> libibverbs man page that if huge pages are used (well, the huge
> pages patch set isn't fully merged, maybe its about time to make
> this happen...) then the actual limit is bigger, e.g follows the
> proportion between the regular to the huge pages used.
>
What you're proposing is to change something that is not accurate in
another not accurate thing. Even when you don't use huge pages, a
calculation based on regular pages would be inaccurate too. That's
because the allocator allocates MTTs in 2^n quantities while the
registered memory need not be sized like that. Moreover, such
calculation is less accurate then what we have now.