Re: light weight user level semaphores

Alan Cox
2001-04-19T21:38:45Z

> Are you sure, you can implement SMP-safe, atomic operations (which you need
> for all up()/down() in user space) WITHOUT using privileged
> instructions on ALL archs Linux supports?

You don't need to. For some architectures the semaphore code would always call
into the kernel. For those that allow fast locks in userspace it won't. The
API is the thing, and the public exposure would I assume be pthreads