Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation

Steven Rostedt
2005-12-16T22:32:41Z

On Fri, 2005-12-16 at 14:19 -0800, Linus Torvalds wrote:
>
> On Fri, 16 Dec 2005, Thomas Gleixner wrote:
> >
> > Well, in case of a semaphore it is a semantically correct use case. In
> > case of of a mutex it is not.
>
> I disagree.
>
> Think of "initialization" as a user. The system starts out initializing
> stuff, and as such the mutex should start out being held. It's that
> simple. It _is_ mutual exclusion, with one user being the early bootup
> state.

That's stretching it quite a bit. So you are saying that the owner is
the first swapper task, from the booting CPU? Well, you better have
that same process unlock that mutex, since a mutex has a owner and the
owner _must_ be the one to unlock it. And in lots of these cases, it's
some other thread that releases the lock.

With mutexs, the owner is not a state, but a task.

-- Steve