On Tue, Feb 04, 2014 at 11:16:58AM -0800, Linus Torvalds wrote:

On Tue, Feb 4, 2014 at 11:05 AM, Peter Zijlstra

quoted

quoted

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.