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Date: Sun, 23 May 2010 23:15:09 +1000 (EST)
From: Bruce Evans <brde@optusnet.com.au>
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org,
	src-committers@FreeBSD.org, Bruce Evans <brde@optusnet.com.au>
Subject: Re: svn commit: r208332 - in head/sys: amd64/include i386/include 
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On Sun, 23 May 2010, Poul-Henning Kamp wrote:

> In message <20100523183502.C13588@delplex.bde.org>, Bruce Evans writes:
>> On Thu, 20 May 2010, Poul-Henning Kamp wrote:
>
>> <machine/atomic.h> should be kernel-only.
>
> No, it absolutely should not, if anything, it should be pushed as
> international standards (with <sys/endian.h>, and <sys/queue.h>).
>
> Atomic operations and write barriers are necessary when multiple
> threads or processes cooperate using shared memory. and if anything
> the bug is that POSIX has not updated pthreads to have these and
> other necessary primitives.  (pthread_mutex_assert_held() for instance).

Pehraps, but <machine/atomic.h> was only designed, implemented and
documented for use in the kernel.  And of course any standardized version
won't look like the FreeBSD kernel one.  The kernel one is too bloated
for me, but a general-purpose one should be even more bloated so as
to support all types and more than atomic ops.

Bruce