Re: Question about barriers for ARM on tools/perf/

From: Peter Zijlstra <peterz@infradead.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>, Ingo Molnar <mingo@kernel.org>,
	David Ahern <dsahern@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
	Namhyung Kim <namhyung@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Question about barriers for ARM on tools/perf/
Date: Fri, 8 May 2015 17:27:59 +0200	[thread overview]
Message-ID: <20150508152759.GO27504@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150508145701.GL7862@kernel.org>

On Fri, May 08, 2015 at 11:57:01AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, May 08, 2015 at 03:48:20PM +0100, Will Deacon escreveu:

> > Do you know what the objection to the intrinsics was? I believe that
> > the __sync versions are deprecated in favour of the C11-like __atomic
> > flavours, so if that was all the objection was about then we could use
> > one or the other depending on what the compiler supports.
> 
> Peter? Ingo?

I cannot remember, the __sync things should mostly work I suppose, and
if you wrap then in the normal atomic interface we don't have to learn
yet another API.

That said, I've successfully lifted this kernel code into userspace in
the past.