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From: David Howells <dhowells@redhat.com>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Alan Cox <alan@redhat.com>, David Howells <dhowells@redhat.com>,
	torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com,
	linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Document Linux's memory barriers [try #2]
Date: Wed, 08 Mar 2006 17:19:41 +0000	[thread overview]
Message-ID: <10095.1141838381@warthog.cambridge.redhat.com> (raw)
In-Reply-To: <20060308154157.GI7301@parisc-linux.org>

Matthew Wilcox <matthew@wil.cx> wrote:

> > That might be worth an example with an if() because PPC will do this and
> > if its a read with a side effect (eg I/O space) you get singed..
> 
> PPC does speculative memory accesses to IO?  Are you *sure*?

Can you do speculative reads from frame buffers?

> # define smp_read_barrier_depends()     do { } while(0)

What's this one meant to do?

> Port space is deprecated though.  PCI 2.3 says:

That's sort of irrelevant for the here. I still need to document the
interaction.

> Since memory write transactions may be posted in bridges anywhere
> in the system, and I/O writes may be posted in the host bus bridge,

I'm not sure whether this is beyond the scope of this document. Maybe the
document's scope needs to be expanded.

David

  reply	other threads:[~2006-03-08 17:20 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-07 17:40 [PATCH] Document Linux's memory barriers David Howells
2006-03-07 10:34 ` Andi Kleen
2006-03-07 18:30   ` David Howells
2006-03-07 11:13     ` Andi Kleen
2006-03-07 19:24       ` David Howells
2006-03-07 18:46     ` Jesse Barnes
2006-03-07 19:23     ` Bryan O'Sullivan
2006-03-07 11:57       ` Andi Kleen
2006-03-07 20:01         ` Jesse Barnes
2006-03-07 21:14         ` Bryan O'Sullivan
2006-03-07 21:24           ` Andi Kleen
2006-03-08  0:36             ` Alan Cox
2006-03-08  0:35         ` Alan Cox
2006-03-07 18:40 ` Alan Cox
2006-03-07 18:54   ` linux-os (Dick Johnson)
2006-03-07 19:06     ` Matthew Wilcox
2006-03-07 19:15       ` linux-os (Dick Johnson)
2006-03-07 19:33     ` Alan Cox
2006-03-07 20:09   ` David Howells
2006-03-08  0:32     ` Alan Cox
2006-03-08  8:25     ` Duncan Sands
2006-03-08 22:06       ` Paul Mackerras
2006-03-08 22:24         ` David S. Miller
2006-03-08 22:31           ` Linus Torvalds
2006-03-08 22:42         ` Alan Cox
2006-03-08  2:07 ` Nick Piggin
2006-03-08  3:10 ` Paul Mackerras
2006-03-08  3:30   ` Linus Torvalds
2006-03-08 12:34     ` David Howells
2006-03-08 16:40       ` Bryan O'Sullivan
2006-03-08  7:41   ` Nick Piggin
2006-03-08 13:19   ` David Howells
2006-03-08 21:49     ` Paul Mackerras
2006-03-08 22:05       ` Alan Cox
2006-03-08 14:37 ` [PATCH] Document Linux's memory barriers [try #2] David Howells
2006-03-08 14:55   ` Alan Cox
2006-03-08 15:41     ` Matthew Wilcox
2006-03-08 17:19       ` David Howells [this message]
2006-03-08 22:10         ` Paul Mackerras
2006-03-08 23:08           ` Ivan Kokshaysky
2006-03-09  1:01             ` Paul Mackerras
2006-03-09 16:02               ` Ivan Kokshaysky
2006-03-08 17:04     ` David Howells
2006-03-08 17:36       ` Alan Cox
2006-03-08 18:35         ` David Howells
2006-03-08 18:45           ` Alan Cox
2006-03-08 18:59             ` David Howells
2006-03-08 11:38               ` Andi Kleen
2006-03-08 19:08             ` David Howells
2006-03-08 19:26               ` Linus Torvalds
2006-03-08 19:31                 ` David Howells
2006-03-09  0:35                   ` Paul Mackerras
2006-03-09  0:54                     ` Linus Torvalds
2006-03-09  1:08                       ` Paul Mackerras
2006-03-09  1:27                         ` Linus Torvalds
2006-03-09  2:38                           ` Nick Piggin
2006-03-09  3:45                           ` Paul Mackerras
2006-03-09  4:36                             ` Jesse Barnes
2006-03-09  7:41                               ` Paul Mackerras
2006-03-09  5:38                             ` Linus Torvalds
2006-03-09 12:27                               ` David Howells
2006-03-09 11:44                             ` Michael Buesch
2006-03-09  4:34                           ` Jesse Barnes
2006-03-09  4:43                             ` Paul Mackerras
2006-03-09 10:05                               ` Jes Sorensen
2006-03-09  0:55                     ` Jesse Barnes
2006-03-09  1:57                       ` Paul Mackerras
2006-03-09  4:26                         ` Jesse Barnes
2006-03-08 19:40                 ` Matthew Wilcox
2006-03-09  0:37                   ` Paul Mackerras
2006-03-09  0:59                     ` Jesse Barnes
2006-03-09  1:36                       ` Paul Mackerras
2006-03-09  4:18                         ` Jesse Barnes
2006-03-08 19:54                 ` Jesse Barnes
2006-03-08 20:02                 ` Alan Cox
2006-03-08 22:01     ` Paul Mackerras
2006-03-08 22:23       ` David S. Miller
2006-03-08 19:37   ` [PATCH] Document Linux's memory barriers [try #3] David Howells
2006-03-09 14:01     ` David Howells
2006-03-08 16:18 ` [PATCH] Document Linux's memory barriers Pavel Machek
2006-03-08 20:16   ` David Howells
2006-03-08 22:01     ` Alan Cox
2006-03-09 11:41       ` David Howells
2006-03-09 12:28         ` Alan Cox
2006-03-09 13:02           ` David Howells
2006-03-09 16:32         ` Linus Torvalds
2006-03-09 17:39           ` David Howells
2006-03-09 17:54             ` Linus Torvalds
2006-03-09 17:56               ` Linus Torvalds

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