From: Roland Dreier <rdreier@cisco.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Linus Torvalds <torvalds@linux-foundation.org>,
Matthew Wilcox <matthew@wil.cx>,
Trent Piepho <tpiepho@freescale.com>,
Russell King <rmk+lkml@arm.linux.org.uk>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
David Miller <davem@davemloft.net>,
linux-arch@vger.kernel.org, scottwood@freescale.com,
linuxppc-dev@ozlabs.org, alan@lxorguk.ukuu.org.uk,
linux-kernel@vger.kernel.org
Subject: Re: MMIO and gcc re-ordering issue
Date: Tue, 10 Jun 2008 12:05:55 -0700 [thread overview]
Message-ID: <adaskvl3yb0.fsf@cisco.com> (raw)
In-Reply-To: <1213121426.8536.7.camel@localhost.localdomain> (James Bottomley's message of "Tue, 10 Jun 2008 13:10:26 -0500")
> me too. That's the whole basis for readX_relaxed() and its cohorts: we
> make our weirdest machines (like altix) conform to the x86 norm. Then
> where it really kills us we introduce additional semantics to selected
> drivers that enable us to recover I/O speed on the abnormal platforms.
Except as I pointed out before, Altix doesn't conform to the norm and
many (most?) drivers are missing mmiowb()s that are needed for Altix.
Just no one has plugged most devices into an Altix (or haven't stressed
the driver in a way that exposes problems of IO ordering between CPUs).
It would be a great thing to use the powerpc trick of setting a flag
that is tested by spin_unlock()/mutex_unlock() and automatically doing
the mmiowb() if needed, and then killing off mmiowb() entirely.
- R.
next prev parent reply other threads:[~2008-06-10 19:05 UTC|newest]
Thread overview: 148+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4833524C.3040207@freescale.com>
[not found] ` <20080520.153947.84346222.davem@davemloft.net>
[not found] ` <4833542E.3040608@freescale.com>
[not found] ` <20080520.155326.195407196.davem@davemloft.net>
[not found] ` <1211516683.8297.271.camel@pasglop>
[not found] ` <Pine.LNX.4.64.0805221553400.8205@t2.domain.actdsltmp>
2008-05-27 1:33 ` MMIO and gcc re-ordering issue Benjamin Herrenschmidt
2008-05-27 1:40 ` David Miller
2008-05-27 2:15 ` Benjamin Herrenschmidt
2008-05-27 2:28 ` David Miller
2008-05-27 3:39 ` Benjamin Herrenschmidt
2008-05-27 15:35 ` Linus Torvalds
2008-05-27 15:35 ` Linus Torvalds
2008-05-27 16:47 ` Linus Torvalds
2008-05-27 17:31 ` Linus Torvalds
2008-06-02 10:36 ` Ingo Molnar
2008-06-02 21:53 ` Benjamin Herrenschmidt
2008-05-27 21:12 ` Benjamin Herrenschmidt
2008-05-27 18:23 ` Trent Piepho
2008-05-27 18:33 ` Scott Wood
2008-05-27 21:10 ` Benjamin Herrenschmidt
2008-05-27 21:30 ` Linus Torvalds
2008-05-27 21:38 ` Alan Cox
2008-05-27 21:53 ` Matthew Wilcox
2008-05-27 21:46 ` Alan Cox
2008-05-27 22:02 ` Linus Torvalds
2008-05-27 21:59 ` Linus Torvalds
2008-05-27 21:38 ` Benjamin Herrenschmidt
2008-05-27 21:42 ` Matthew Wilcox
2008-05-27 22:17 ` Benjamin Herrenschmidt
2008-05-28 8:36 ` Haavard Skinnemoen
2008-05-29 11:05 ` Pantelis Antoniou
2008-05-30 1:13 ` Benjamin Herrenschmidt
2008-05-30 6:07 ` Haavard Skinnemoen
2008-05-30 7:24 ` Benjamin Herrenschmidt
2008-05-30 8:27 ` Haavard Skinnemoen
2008-05-30 9:22 ` Geert Uytterhoeven
2008-06-02 8:11 ` Haavard Skinnemoen
2008-06-02 15:48 ` Scott Wood
2008-06-03 7:46 ` Haavard Skinnemoen
2008-06-04 15:31 ` Linus Torvalds
2008-05-27 21:55 ` Linus Torvalds
2008-05-27 22:19 ` Benjamin Herrenschmidt
2008-05-29 7:10 ` Arnd Bergmann
2008-05-29 7:10 ` Arnd Bergmann
2008-05-29 10:46 ` Alan Cox
2008-06-02 7:24 ` Russell King
2008-06-02 7:24 ` Russell King
2008-06-03 4:16 ` Nick Piggin
2008-06-03 4:16 ` Nick Piggin
2008-06-03 4:32 ` Benjamin Herrenschmidt
2008-06-03 6:11 ` Nick Piggin
2008-06-03 6:48 ` Benjamin Herrenschmidt
2008-06-03 6:53 ` Paul Mackerras
2008-06-03 7:18 ` Nick Piggin
2008-06-03 7:18 ` Nick Piggin
2008-06-03 14:47 ` Linus Torvalds
2008-06-03 18:47 ` Trent Piepho
2008-06-03 18:55 ` Matthew Wilcox
2008-06-03 19:57 ` Trent Piepho
2008-06-03 21:35 ` Matthew Wilcox
2008-06-03 21:58 ` Trent Piepho
2008-06-04 2:00 ` Nick Piggin
2008-06-03 19:07 ` Linus Torvalds
2008-06-04 2:05 ` Nick Piggin
2008-06-04 2:46 ` Linus Torvalds
2008-06-04 11:47 ` Alan Cox
2008-06-04 11:47 ` Alan Cox
2008-06-10 6:56 ` Nick Piggin
2008-06-10 17:41 ` Jesse Barnes
2008-06-10 18:10 ` James Bottomley
2008-06-10 19:05 ` Roland Dreier [this message]
2008-06-10 19:19 ` Jesse Barnes
2008-06-11 3:29 ` Nick Piggin
2008-06-11 3:29 ` Nick Piggin
2008-06-11 3:40 ` Benjamin Herrenschmidt
2008-06-11 4:06 ` Nick Piggin
2008-06-11 16:07 ` Jesse Barnes
2008-06-11 16:07 ` Jesse Barnes
2008-06-12 11:27 ` Nick Piggin
2008-06-11 4:18 ` Paul Mackerras
2008-06-11 5:00 ` Nick Piggin
2008-06-11 5:13 ` Paul Mackerras
2008-06-11 5:35 ` Nick Piggin
2008-06-11 6:02 ` Nick Piggin
2008-06-12 12:14 ` Paul Mackerras
2008-06-12 13:08 ` Nick Piggin
2008-06-11 14:46 ` Linus Torvalds
2008-06-11 5:20 ` Paul Mackerras
2008-06-11 5:20 ` Paul Mackerras
2008-06-04 2:19 ` Nick Piggin
2008-06-03 19:43 ` Trent Piepho
2008-06-03 21:33 ` Matthew Wilcox
2008-06-03 21:44 ` Trent Piepho
2008-06-04 2:25 ` Nick Piggin
2008-06-04 2:25 ` Nick Piggin
2008-06-04 6:39 ` Trent Piepho
2008-06-03 22:26 ` Benjamin Herrenschmidt
2008-05-27 3:42 ` Arjan van de Ven
2008-05-27 4:08 ` Roland Dreier
2008-05-27 4:20 ` Arjan van de Ven
2008-05-27 7:08 ` Benjamin Herrenschmidt
2008-05-27 7:08 ` Benjamin Herrenschmidt
2008-05-27 15:50 ` Roland Dreier
2008-05-27 16:37 ` James Bottomley
2008-05-27 17:38 ` Roland Dreier
2008-05-27 17:53 ` James Bottomley
2008-05-27 18:07 ` Roland Dreier
2008-05-27 18:17 ` Roland Dreier
2008-05-27 21:23 ` Chris Friesen
2008-05-27 21:23 ` Chris Friesen
2008-05-27 21:29 ` Roland Dreier
2008-05-27 23:04 ` Paul Mackerras
2008-05-27 21:11 ` Benjamin Herrenschmidt
2008-05-27 21:33 ` Roland Dreier
2008-05-27 22:13 ` Benjamin Herrenschmidt
2008-05-27 22:39 ` Roland Dreier
2008-05-29 14:47 ` Jes Sorensen
2008-05-29 15:01 ` James Bottomley
2008-05-30 9:36 ` Jes Sorensen
2008-05-30 17:21 ` Jesse Barnes
2008-05-30 17:21 ` Jesse Barnes
2008-05-31 7:57 ` Jeremy Higdon
2008-05-29 21:40 ` Benjamin Herrenschmidt
2008-05-29 21:48 ` Trent Piepho
2008-05-29 22:05 ` Benjamin Herrenschmidt
2008-05-30 1:53 ` Trent Piepho
2008-05-29 21:53 ` Jesse Barnes
2008-05-29 21:53 ` Jesse Barnes
2008-05-30 9:39 ` Jes Sorensen
2008-05-30 9:48 ` Jes Sorensen
2008-05-31 8:14 ` Pavel Machek
2008-06-02 9:48 ` Jes Sorensen
2008-05-29 22:06 ` Roland Dreier
2008-05-29 22:25 ` Trent Piepho
2008-05-29 22:25 ` Trent Piepho
2008-05-30 3:56 ` Paul Mackerras
2008-05-31 7:52 ` Jeremy Higdon
2008-06-02 9:56 ` Jes Sorensen
2008-06-02 21:02 ` Jeremy Higdon
2008-06-03 4:33 ` Nick Piggin
2008-06-03 8:15 ` Jeremy Higdon
2008-06-03 8:15 ` Jeremy Higdon
2008-06-03 8:19 ` Nick Piggin
2008-06-03 8:45 ` Jeremy Higdon
2008-06-03 16:52 ` Jesse Barnes
2008-06-03 16:52 ` Jesse Barnes
2008-06-05 8:40 ` Jes Sorensen
2008-06-05 8:43 ` Benjamin Herrenschmidt
2008-06-12 15:07 ` Matthew Wilcox
2008-06-13 0:07 ` Benjamin Herrenschmidt
2008-05-31 8:04 ` Pavel Machek
2008-05-27 8:24 ` Alan Cox
2008-05-27 15:28 ` Jonathan Corbet
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