From: "Bryan O'Sullivan" <bos@pathscale.com>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@suse.de>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Define wc_wmb, a write barrier for PCI write combining
Date: Tue, 28 Feb 2006 10:20:14 -0800 [thread overview]
Message-ID: <1141150814.24103.37.camel@camp4.serpentine.com> (raw)
In-Reply-To: <20060228175838.GD24306@kvack.org>
On Tue, 2006-02-28 at 12:58 -0500, Benjamin LaHaise wrote:
> On Tue, Feb 28, 2006 at 09:50:08AM -0800, Bryan O'Sullivan wrote:
> > The last 32-bit write triggers the chip to put the packet on the wire.
> > We make sure it happens after the earlier bulk write using a barrier.
>
> The barrier you're looking for is wmb() in asm/system.h, which is defined
> on both SMP and UP.
No. We're writing to a region that we've marked as write combining, so
the processor or north bridge will not write in program order. It's
free to write out the write combining store buffers in whatever order it
feels like, unless forced to do otherwise.
<b
next prev parent reply other threads:[~2006-02-28 18:20 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-25 4:20 Bryan O'Sullivan
2006-02-25 4:43 ` Andi Kleen
2006-02-25 7:34 ` Bryan O'Sullivan
2006-02-25 13:28 ` Andi Kleen
2006-02-25 17:20 ` Bryan O'Sullivan
2006-02-25 19:01 ` Bryan O'Sullivan
2006-02-28 17:44 ` Jesse Barnes
2006-02-28 17:50 ` Roland Dreier
2006-02-28 17:50 ` Jesse Barnes
2006-02-28 17:52 ` Bryan O'Sullivan
2006-02-28 17:59 ` Jesse Barnes
2006-02-25 14:28 ` Benjamin LaHaise
2006-02-25 17:11 ` Bryan O'Sullivan
2006-02-25 17:41 ` Benjamin LaHaise
2006-02-28 17:50 ` Bryan O'Sullivan
2006-02-28 17:58 ` Benjamin LaHaise
2006-02-28 18:20 ` Bryan O'Sullivan [this message]
2006-02-28 19:03 ` Benjamin LaHaise
2006-02-28 19:20 ` Bryan O'Sullivan
2006-02-28 19:33 ` Andi Kleen
2006-02-28 19:44 ` Bryan O'Sullivan
2006-03-01 19:20 ` Bryan O'Sullivan
2006-03-01 19:27 ` Andi Kleen
2006-03-01 19:43 ` Bryan O'Sullivan
2006-03-01 19:49 ` Andi Kleen
2006-03-01 20:05 ` Bryan O'Sullivan
2006-03-01 20:26 ` Benjamin LaHaise
2006-03-01 20:35 ` Bryan O'Sullivan
2006-02-28 19:34 ` Benjamin LaHaise
2006-02-28 18:22 ` Christopher Friesen
2006-02-28 10:01 ` Jes Sorensen
2006-02-28 15:42 ` Roland Dreier
2006-02-28 16:08 ` Jes Sorensen
2006-02-28 17:02 ` Roland Dreier
2006-02-28 17:13 ` Jesse Barnes
2006-02-28 17:20 ` Jes Sorensen
2006-03-01 8:16 ` Jeremy Higdon
2006-03-01 8:24 ` Jeremy Higdon
2006-02-28 17:11 ` Jesse Barnes
2006-02-28 17:57 ` Bryan O'Sullivan
2006-02-28 18:07 ` linux-os (Dick Johnson)
2006-02-28 18:24 ` Christopher Friesen
2006-03-01 10:45 ` Jes Sorensen
2006-03-01 17:04 ` Roland Dreier
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