On Mon, Jul 27, 2015 at 10:14:30AM +0100, Peter Zijlstra wrote: > On Fri, Jul 24, 2015 at 03:04:34PM +0100, Will Deacon wrote: > > This patch introduces three new ordering semantics for these operations: > > > > - *_relaxed: No ordering guarantees. This is similar to what we have > > already for the non-return atomics (e.g. atomic_add). > > > > - *_acquire: ACQUIRE semantics, similar to smp_load_acquire. > > > > - *_release: RELEASE semantics, similar to smp_store_release. > > Do we want to further specify that for the RmW operations the Read/load > will provide the acquire and the Write/store the release? Yeah, that's not a bad idea, but if we add that then I probably need to re-iterate the cmpxchg strangeness since a failed cmpxchg_acquire would still not have barrier semantics with the current implementation even though it must have performed a Read/load access. Will -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
