Re: [Xenomai-core] First thoughts on fast xnsynch

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
> Hi Gilles,
> 
> I spent a few brain cycles on the design of a generic fast-lock via
> xnsynch. The first thing was defining the lock word and going through
> its use cases.
> 
> You suggested to realize lock stealing directly in user space, but I
> don't see now how this should work reasonably. Our problem is that we
> would have to atomically check for the woken state AND compare the
> current priority against the owner ones. Imaginable only if we replicate
> the priorities into the lock word - but this makes things at least
> horribly complicated (e.g. when priorities change). So I think we have
> to drop this goal. Or what did you have in mind?

No, you are right, it is a scheduler's decition, so must be done in
kernel-space.

-- 
					    Gilles.