On Thu, Jul 30, 2015 at 08:34:52AM -0700, Paul E. McKenney wrote: > On Thu, Jul 30, 2015 at 04:44:55PM +0200, Peter Zijlstra wrote:
> > If the extra read before the cmpxchg() does not hurt, we should do the > > same for mutex and make the above redundant. > > I am pretty sure that different hardware wants it done differently. :-/ I think that most archs won't notice since any RmW includes a load of that variable anyhow. The only case where it can matter is if the RmW is done outside of the normal cache hierarchy -- like on Power, where the ll/sc bypasses the L1. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
