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From: Matthew Wilcox <matthew@wil.cx>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux-arch@vger.kernel.org, Nick Piggin <nickpiggin@yahoo.com.au>,
	Roland Dreier <rdreier@cisco.com>, Jes Sorensen <jes@sgi.com>,
	linux-kernel@vger.kernel.org, Jeremy Higdon <jeremy@sgi.com>,
	David Miller <davem@davemloft.net>,
	linuxppc-dev@ozlabs.org, Jesse Barnes <jbarnes@virtuousgeek.org>,
	scottwood@freescale.com, torvalds@linux-foundation.org,
	tpiepho@freescale.com, alan@lxorguk.ukuu.org.uk,
	Arjan van de Ven <arjan@infradead.org>
Subject: Re: MMIO and gcc re-ordering issue
Date: Thu, 12 Jun 2008 09:07:16 -0600	[thread overview]
Message-ID: <20080612150716.GX30405@parisc-linux.org> (raw)
In-Reply-To: <1212655433.9496.109.camel@pasglop>

On Thu, Jun 05, 2008 at 06:43:53PM +1000, Benjamin Herrenschmidt wrote:
> Note that the powerpc implementation currently clears the flag
> on spin_lock and tests it on unlock. We are considering changing
> that to not touch the flag on spin_lock and just clear it whenever
> we do a sync (ie, on unlock, on explicit mmiowb, and possibly even
> on readl's where we happen to do sync's).

Your current scheme sounds like it's broken for

spin_lock(a)
writel();
spin_lock(b);
spin_unlock(b);
spin_unlock(a);

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

  reply	other threads:[~2008-06-12 15:07 UTC|newest]

Thread overview: 160+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-20 20:40 [PATCH] [POWERPC] Improve (in|out)_beXX() asm code Trent Piepho
2008-05-20 21:16 ` Benjamin Herrenschmidt
2008-05-20 21:38   ` Scott Wood
2008-05-20 22:02     ` Benjamin Herrenschmidt
2008-05-20 22:21       ` Trent Piepho
2008-05-20 22:15     ` Alan Cox
2008-05-20 22:35       ` Scott Wood
2008-05-20 22:39         ` David Miller
2008-05-20 22:43           ` Scott Wood
2008-05-20 22:53             ` David Miller
2008-05-23  4:24               ` Benjamin Herrenschmidt
2008-05-22 22:56                 ` Trent Piepho
2008-05-23 12:36                   ` MMIO and gcc re-ordering (Was: [PATCH] [POWERPC] Improve (in|out)_beXX() asm code) Benjamin Herrenschmidt
2008-05-23 12:50                     ` Benjamin Herrenschmidt
2008-05-23 21:14                       ` Scott Wood
2008-05-23 22:47                         ` Benjamin Herrenschmidt
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 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 10:46                                           ` Alan Cox
2008-06-02  7:24                                       ` Russell King
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 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
2008-06-10  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
2008-06-10 19:19                                                         ` Jesse Barnes
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
2008-06-12 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
2008-06-04  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  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 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 21:29                                           ` 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
2008-05-31  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
2008-05-30  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
2008-05-30  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  8:19                                               ` Nick Piggin
2008-06-03  8:45                                                 ` Jeremy Higdon
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 [this message]
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
2008-05-20 22:55         ` [PATCH] [POWERPC] Improve (in|out)_beXX() asm code Trent Piepho
2008-05-21 14:01           ` Benjamin Herrenschmidt
2008-05-20 22:00   ` Trent Piepho
2008-05-21 14:00     ` Benjamin Herrenschmidt
2008-05-21 19:44       ` Trent Piepho
2008-05-21 20:41         ` Benjamin Herrenschmidt
2008-05-20 22:00 ` Andreas Schwab
2008-05-20 22:11   ` Trent Piepho
2008-05-20 22:47     ` Andreas Schwab
2008-05-20 23:14       ` Trent Piepho
2008-05-21  8:03         ` Andreas Schwab
2008-05-21 20:25           ` Trent Piepho
2008-05-27 23:48           ` [PATCH V2] [POWERPC] Improve (in|out)_[bl]eXX() " Trent Piepho

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