Messages in this thread | | | Date | Wed, 28 Oct 2015 06:33:56 +0900 | Subject | Re: [PATCH 3/4] x86,asm: Re-work smp_store_mb() | From | Linus Torvalds <> |
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On Wed, Oct 28, 2015 at 4:53 AM, Davidlohr Bueso <dave@stgolabs.net> wrote: > > Note that this might affect callers that could/would rely on the > atomicity semantics, but there are no guarantees of that for > smp_store_mb() mentioned anywhere, plus most archs use this anyway. > Thus we continue to be consistent with the memory-barriers.txt file, > and more importantly, maintain the semantics of the smp_ nature.
So I dislike this patch, mostly because it now makes it obvious that smp_store_mb() seems to be totally pointless. Every single implementation is now apparently WRITE_ONCE+smp_mb(), and there are what, five users of it, so why not then open-code it?
But more importantly, is the "WRITE_ONCE()" even necessary? If there are no atomicity guarantees, then why bother with WRTE_ONCE() either?
So with this patch, the whole thing becomes pointless, I feel. (Ok, so it may have been pointless before too, but at least before this patch it generated special code, now it doesn't). So why carry it along at all?
Linus
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