Re: [PATCH 6/24] make atomic_read() behave consistently on frv

Chris Snook
2007-08-09T17:00:57Z

Chris Snook wrote:
> From: Chris Snook <csnook@redhat.com>
>
> Make atomic_read() volatile on frv. This ensures that busy-waiting
> for an interrupt handler to change an atomic_t won't get compiled to an
> infinite loop, consistent with SMP architectures.

To head off the criticism, I admit this is an oversimplification, and true
busy-waiters should be using cpu_relax(), which contains a barrier. As
discussed in recent threads, there are other cases which can be optimized by
removing the need for a barrier, and having behavior consistent with
architectures where the benefit is more profound is also valuable.

-- Chris