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Date: Mon, 16 May 2016 14:27:01 -0400
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20160516182701.GA13292@flamenco>
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Subject: Re: [Qemu-devel] [PATCH v5 06/18] atomics: add atomic_read_acquire
 and atomic_set_release
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To: Pranith Kumar <bobby.prani@gmail.com>
Cc: MTTCG Devel <mttcg@listserver.greensocs.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, QEMU Developers <qemu-devel@nongnu.org>, Sergey Fedorov <serge.fdrv@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Alex =?iso-8859-1?Q?Benn=E9e?= <alex.bennee@linaro.org>, Richard Henderson <rth@twiddle.net>

On Sun, May 15, 2016 at 06:22:36 -0400, Pranith Kumar wrote:
> On Fri, May 13, 2016 at 11:34 PM, Emilio G. Cota <cota@braap.org> wrote:
> > When __atomic is not available, we use full memory barriers instead
> > of smp/wmb, since acquire/release barriers apply to all memory
> > operations and not just to loads/stores, respectively.
> 
> If it is not too late can we rename this to
> atomic_load_acquire()/atomic_store_release() like in the linux kernel?

I'd keep read/set just for consistency with the rest of the file.

BTW in the kernel, atomic_{read/set}_{acquire/release} are defined
in include/linux/atomic.h:

    #ifndef atomic_read_acquire
    #define  atomic_read_acquire(v)         smp_load_acquire(&(v)->counter)
    #endif

    #ifndef atomic_set_release
    #define  atomic_set_release(v, i)       smp_store_release(&(v)->counter, (i))
    #endif

The smp_load/store variants are called much more frequently, though.

Thanks,

		Emilio