Messages in this thread | | | Date | Fri, 25 Nov 2016 17:17:09 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 0/3] virtio/vringh: kill off ACCESS_ONCE() |
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On Fri, Nov 25, 2016 at 04:10:04PM +0000, Mark Rutland wrote: > On Fri, Nov 25, 2016 at 04:21:39PM +0100, Dmitry Vyukov wrote:
> > What are use cases for such primitive that won't be OK with "read once > > _and_ atomically"? > > I have none to hand.
Whatever triggers the __builtin_memcpy() paths, and even the size==8 paths on 32bit.
You could put a WARN in there to easily find them.
The advantage of introducing the SINGLE_{LOAD,STORE}() helpers is that they compiletime validate this the size is 'right' and can runtime check alignment constraints.
IE, they are strictly stronger than {READ,WRITE}_ONCE().
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