linux-kernel - Re: [RFC PATCH 00/15] Provide atomics and bitops implemented with ISO C++11 atomics

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Message-ID: <20160518174506.GH3206@twins.programming.kicks-ass.net>
Date:	Wed, 18 May 2016 19:45:06 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	David Howells <dhowells@...hat.com>
Cc:	linux-arch@...r.kernel.org, x86@...nel.org, will.deacon@....com,
	linux-kernel@...r.kernel.org, ramana.radhakrishnan@....com,
	paulmck@...ux.vnet.ibm.com, dwmw2@...radead.org
Subject: Re: [RFC PATCH 00/15] Provide atomics and bitops implemented with
 ISO C++11 atomics

On Wed, May 18, 2016 at 04:10:37PM +0100, David Howells wrote:
>  (3) I've added cmpxchg_return() and try_cmpxchg() to replace cmpxchg().
>      I've also provided atomicX_t variants of these.  These return the
>      boolean return value from the __atomic_compare_exchange_n() function
>      (which is carried in the Z flag on x86).  Should this be rolled out
>      even without the ISO atomic implementation?

I suppose we could, esp. with GCC-6.1 having cc-output using the Z flag
should result in nicer code.