On Thu, Nov 21, 2013 at 10:17:36AM +0000, Will Deacon wrote: > On Thu, Nov 21, 2013 at 04:53:33AM +0000, Paul E. McKenney wrote: > > On Wed, Nov 20, 2013 at 03:51:54PM -0800, Tim Chen wrote: > > > If we intend to use smp_load_acquire and smp_store_release extensively > > > for locks, making RCsc semantics the default will simply things a lot. > > > > The other option is to weaken lock semantics so that unlock-lock no > > longer implies a full barrier, but I believe that we would regret taking > > that path. (It would be OK by me, I would just add a few smp_mb() > > calls on various slowpaths in RCU. But...) > > Unsurprisingly, my vote is for RCsc semantics. That was in fact my guess. ;-) > One major advantage (in my opinion) of the acquire/release accessors is that > they feel intuitive in an area where intuition is hardly rife. I believe > that the additional reordering permitted by RCpc detracts from the relative > simplicity of what is currently being proposed. Fair point! Let's see what others (both hackers and architectures) say. Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>