On Wed, Sep 16, 2015 at 11:49:32PM +0800, Boqun Feng wrote:
> Implement xchg_relaxed and define atomic{,64}_xchg_* as xchg_relaxed,
> based on these _relaxed variants, release/acquire variants can be built.
>
> Note that xchg_relaxed and atomic_{,64}_xchg_relaxed are not compiler
> barriers.
Hmm, and I note your previous patch creating the regular _relaxed
thingies also removes the memory clobber.
And looking at the ARM _relaxed patch from Will, I see their _relaxed
ops are also not a compiler barrier.
I must say I'm somewhat surprised by this level of relaxation, I had
expected to only loose SMP barriers, not the program order ones.
Is there a good argument for this?
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