Re: [PATCH 0/24] make atomic_read() behave consistently across allarchitectures

From: Christoph Lameter
Date: Tue Aug 14 2007 - 19:14:58 EST


On Tue, 14 Aug 2007, Chris Snook wrote:

> Because atomic operations are generally used for synchronization, which
> requires volatile behavior. Most such codepaths currently use an inefficient
> barrier(). Some forget to and we get bugs, because people assume that
> atomic_read() actually reads something, and atomic_write() actually writes
> something. Worse, these are architecture-specific, even compiler
> version-specific bugs that are often difficult to track down.

Looks like we need to have lock and unlock semantics?

atomic_read()

which has no barrier or volatile implications.

atomic_read_for_lock

Acquire semantics?


atomic_read_for_unlock

Release semantics?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/