Re: [RFC PATCH 03/15] Provide atomic_t functions implemented with ISO-C++11 atomics

[Peter Zijlstra]

On Wed, May 18, 2016 at 04:10:59PM +0100, David Howells wrote:
>      (b) An ISYNC instruction is emitted as the Acquire barrier with
>      	 __ATOMIC_SEQ_CST, but I'm not sure this is strong enough.
> 
>      (c) An LWSYNC instruction is emitted as the Release barrier with
>      	 __ATOMIC_ACQ_REL or __ATOMIC_RELEASE.  Is this strong enough that
>      	 we could use these memorders instead?

Our atomic acquire/release operations are RCpc, so yes. Our locks would
like to be RCsc but currently powerpc is an RCpc holdout there as well.