On Tue, Feb 04, 2014 at 11:16:58AM -0800, Linus Torvalds wrote: > On Tue, Feb 4, 2014 at 11:05 AM, Peter Zijlstra > > > >> So writes move down, not up. > > > > Right, but the ll-sc store might move down over a later store. > > Unlikely. The thing is, in order for the sc to succeed, it has to > already have hit the cache coherency domain (or at least reserved it - > ie maybe the value is not actually *in* the cache, but the sc needs to > have gotten exclusive access to the cacheline). > > So just how do you expect a later store (that is *after* the > conditional branch that tests the result of the sc) to move up before > it? Ah, I completely overlooked the control dependency to the subsequent store. Yes, given that this makes sense.
