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. No, *everyone* (except arch-only non-alpha developer) needs to know about it. x86 especially is a reference and often is a proving ground for code that becomes generic, so I'd say even x86 developers should need to know about it too. > Maybe just a comment? At the end of the day I don't care that much. I'm surprised you do, but I'll do whatever it takes to get merged ;) > 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? I will just re-review that I have my pointer following sequence correct, it could be that I have one too many... but anyway it is needed for lower levels I guess (as a general pattern -- in the actual case of pagetable walking, I don't think it matters anywhere if a pointer gets refetched after being dereferenced) -- 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
