From: "Christopher Friesen" <cfriesen@nortel.com>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: "Bryan O'Sullivan" <bos@pathscale.com>,
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 12:22:52 -0600 [thread overview]
Message-ID: <440494FC.9050400@nortel.com> (raw)
In-Reply-To: <20060228175838.GD24306@kvack.org>
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.
That will synchronize with other CPUs as well, which may not necessarily
be needed.
On PPC for instance, you could implement the desired semantics using
"eieio" (enforce in-order execution of IO). This is lighter weight than
a full "sync", which is what wmb() maps to.
Chris
next prev parent reply other threads:[~2006-02-28 18:23 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-25 4:20 [PATCH] Define wc_wmb, a write barrier for PCI write combining 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=440494FC.9050400@nortel.com \
--to=cfriesen@nortel.com \
--cc=ak@suse.de \
--cc=akpm@osdl.org \
--cc=bcrl@kvack.org \
--cc=bos@pathscale.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox