On Tue, May 06, 2008 at 12:11:53PM -0700, Paul E. McKenney wrote: > On Tue, May 06, 2008 at 07:53:23AM -0700, Linus Torvalds wrote: > > > > > > On Tue, 6 May 2008, Nick Piggin wrote: > > > > > > Right. As the comment says, the x86 stuff is kind of a "reference" > > > implementation, although if you prefer it isn't there, then I I can > > > easily just make it alpha only. > > > > If there really was a point in teaching people about > > "read_barrier_depends()", I'd agree that it's probably good to have it as > > a reference in the x86 implementation. > > > > But since alpha is the only one that needs it, and is likely to remain so, > > it's not like we ever want to copy that code to anything else, and it > > really is better to make it alpha-only if the code is so much uglier. > > > > Maybe just a comment? > > > > As to the ACCESS_ONCE() thing, thinking about it some more, I doubt it > > really matters. We're never going to change pgd anyway, so who cares if we > > access it once or a hundred times? > > If we are never going to change mm->pgd, then why do we need the > smp_read_barrier_depends()? Is this handling the initialization > case or some such? No, I had another look and I think Linus is correct. We don't need it for mm->pgd. -- 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
