From: "Brian J. Watson" <Brian.J.Watson@compaq.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: marcelo@conectiva.com.br, linux-kernel@vger.kernel.org,
dhowells@redhat.com, hch@caldera.de
Subject: Re: [PATCH] 2.4.18-pre9, trylock for read/write semaphores
Date: Tue, 12 Feb 2002 17:47:11 -0800 [thread overview]
Message-ID: <3C69C59F.F86BF8F9@compaq.com> (raw)
In-Reply-To: <E16amMb-0003RQ-00@the-village.bc.nu>
Alan Cox wrote:
>
> > + new = old + RWSEM_ACTIVE_READ_BIAS;
> > + if (cmpxchg(&sem->count, old, new) == old)
> > + return 1;
>
> cmpxchg isnt present on i386
According to arch/i386/config.in, the generic spinlock version would be
used for vintage 386 chips. I think that's due to similar concerns about
the xadd instruction.
--
Brian Watson | "Now I don't know, but I been told it's
Linux Kernel Developer | hard to run with the weight of gold,
Open SSI Clustering Project | Other hand I heard it said, it's
Compaq Computer Corp | just as hard with the weight of lead."
Los Angeles, CA | -Robert Hunter, 1970
mailto:Brian.J.Watson@compaq.com
http://opensource.compaq.com/
next prev parent reply other threads:[~2002-02-13 2:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-12 22:45 [PATCH] 2.4.18-pre9, trylock for read/write semaphores bwatson
2002-02-12 23:29 ` Alan Cox
2002-02-13 1:47 ` Brian J. Watson [this message]
2002-02-13 7:47 ` David Howells
2002-02-13 8:19 ` David Howells
2002-02-14 0:13 ` Brian J. Watson
2002-02-21 18:04 Kendrick M. Smith
2002-02-21 21:54 ` Brian J. Watson
2002-02-21 23:02 ` Kendrick M. Smith
2002-02-21 23:26 ` Brian J. Watson
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