make concurrency kit a module

[Warner Losh]

On Wed, May 17, 2017 at 11:53 PM, Baptiste Daroussin <bapt at freebsd.org> wrote:
> On Wed, May 17, 2017 at 06:04:09PM -0700, Adrian Chadd wrote:
>> https://reviews.freebsd.org/D10778
>>
>
> Except there are plans to use it elsewhere. Many areas may be improved using it.
>
> Having it as a module would mean some devs might refrain from using it because
> there is no waranty for it to be there
>
> Areas like VFS and network stack could have a good benefice from using it.
>
> Out of curiousity what size is saved?

I'd planned on using it newbus to solve the lifetime issues we have
with device_t's....

Warner