[openib-general] Re: [PATCH 10 of 18] ipath - support for userspace apps using core driver

[Bryan O'Sullivan]

On Wed, 2006-03-22 at 19:06 -0800, Andrew Morton wrote:

> CPU topology is available in sysfs - it shouild be possible to push policy
> decisions like this up to userspace.

We covered this in an earlier round of submission, but I should have
updated the inline comments.

While we expose a way for userspace to open an explicit device based on
its knowledge of topology, I think we need a "take your best shot" minor
number, too, which is what this is.

If we *don't* provide one, userspace can end up with exactly the kinds
of messy race situations that used to be seen with ptys before /dev/ptmx
and /dev/pts came along.

	<b