What parts of UMA are part of the stable ABI?

[Ryan Stone]

On Wed, Mar 18, 2015 at 10:24 AM, John Baldwin <jhb at freebsd.org> wrote:

> I do think the normal zone callbacks passed to uma_zcreate() are too public
> to change.  Or at least, you would need to do some crazy ABI shim where you
> have a uma_zcreate_new() that you map to uma_zcreate() via a #define for
> the API, but include a legacy uma_zcreate() symbol that older modules can
> call (and then somehow tag the old function pointers via an internal flag
> in the zone and patch UMA to cast to the old function signatures for zones
> with that flag).
>

I really wasn't clear here.  I definitely don't think that changing the
ctor, etc to accept a size_t is MFC'able, and I don't think that the
problem (which is really only theoretical at this point) warrants an MFC to
-stable.  I was talking about potentially doing it in a separate commit to
head, but that does leave -stable and head with a different API.  This can
be painful for downstream consumers to deal with, which is why I wanted
comments.