Re: [PATCH] Lightweight userspace semaphores...

[Linus Torvalds]

On Mon, 25 Feb 2002, Rusty Russell wrote:
> >
> >   sys_sem_create()
> >   sys_sem_destroy()
>
> There is no create and destroy (init is purely userspace).  There is
> "this is a semapore: up it".  This is a feature.

No, that's a bug.

You have to realize that there are architectures that need special
initialization and page allocation for semaphores: they need special flags
in the TLB for "careful access", for example (sometimes the careful access
ends up being non-cached).

You can't just put semaphores anywhere and tell the kernel to try to fix
up whatever happened.

			Linus