Re: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbsimplementation

Andrew Morton
2005-04-25T23:18:29Z

Timur Tabi <timur.tabi@ammasso.com> wrote:
>
> Bob Woodruff wrote:
>
> > There definitely needs to be a mechanism to prevent people from pinning
> > too much memory.
>
> Any limit would have to be very high - definitely more than just half. What if the
> application needs to pin 2GB? The customer is not going to buy 4+ GB of RAM just because
> Linux doesn't like pinning more than half. In an x86-32 system, that would required PAE
> support and slow everything down.
>
> Off the top of my head, I'd say Linux would need to allow all but 512MB to be pinned. So
> you have 3GB of RAM, Linux should allow you to pin 2.5GB.
>

You can pin the whole darn lot *if you have the correct privileges*.