From: Scott Wood <scottwood@freescale.com>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: netdev@vger.kernel.org, jgarzik@pobox.com, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH v2] gianfar: Add I/O barriers when touching buffer descriptor ownership.
Date: Wed, 02 May 2007 16:30:19 -0500 [thread overview]
Message-ID: <463902EB.8070401@freescale.com> (raw)
In-Reply-To: <41B347BE-06AA-4346-BEFB-19DFB52AC533@kernel.crashing.org>
Kumar Gala wrote:
> Why doesn't marking the bdp pointer volatile resolve the issue in
> gfar_clean_rx_ring() to ensure load ordering?
Because that only addresses compiler reordering (and does so in a rather
clumsy way -- not all accesses need to be strongly ordered), not
hardware reordering.
-Scott
WARNING: multiple messages have this Message-ID (diff)
From: Scott Wood <scottwood@freescale.com>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: jgarzik@pobox.com, netdev@vger.kernel.org, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH v2] gianfar: Add I/O barriers when touching buffer descriptor ownership.
Date: Wed, 02 May 2007 16:30:19 -0500 [thread overview]
Message-ID: <463902EB.8070401@freescale.com> (raw)
In-Reply-To: <41B347BE-06AA-4346-BEFB-19DFB52AC533@kernel.crashing.org>
Kumar Gala wrote:
> Why doesn't marking the bdp pointer volatile resolve the issue in
> gfar_clean_rx_ring() to ensure load ordering?
Because that only addresses compiler reordering (and does so in a rather
clumsy way -- not all accesses need to be strongly ordered), not
hardware reordering.
-Scott
next prev parent reply other threads:[~2007-05-02 21:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-02 19:57 [PATCH v2] gianfar: Add I/O barriers when touching buffer descriptor ownership Scott Wood
2007-05-02 20:09 ` Kumar Gala
2007-05-02 20:09 ` Kumar Gala
2007-05-02 20:12 ` Scott Wood
2007-05-02 20:12 ` Scott Wood
2007-05-02 20:20 ` Kumar Gala
2007-05-02 20:20 ` Kumar Gala
2007-05-02 20:40 ` Scott Wood
2007-05-02 20:40 ` Scott Wood
2007-05-02 21:23 ` Kumar Gala
2007-05-02 21:23 ` Kumar Gala
2007-05-02 21:30 ` Scott Wood [this message]
2007-05-02 21:30 ` Scott Wood
2007-05-03 2:10 ` Kumar Gala
2007-05-03 2:10 ` Kumar Gala
2007-05-03 16:00 ` Scott Wood
2007-05-03 16:38 ` Segher Boessenkool
2007-05-03 16:38 ` Segher Boessenkool
2007-05-02 23:42 ` Segher Boessenkool
2007-05-04 22:13 ` Linas Vepstas
2007-05-04 22:13 ` Linas Vepstas
2007-05-04 23:24 ` Olof Johansson
2007-05-05 0:41 ` Segher Boessenkool
2007-05-05 0:41 ` Segher Boessenkool
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