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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>,
	linux-ia64@vger.kernel.org, Jesse Barnes <jesse.barnes@intel.com>,
	linuxppc-dev@ozlabs.org
Subject: Re: wmb vs mmiowb
Date: Thu, 23 Aug 2007 09:27:15 +0200	[thread overview]
Message-ID: <1187854035.5972.4.camel@localhost.localdomain> (raw)
In-Reply-To: <alpine.LFD.0.999.0708221049560.30176@woody.linux-foundation.org>


> Of course, the normal memory barrier would usually be a "spin_unlock()" or 
> something like that, not a "wmb()". In fact, I don't think the powerpc 
> implementation (as an example of this) will actually synchronize with 
> anything *but* a spin_unlock().

We are even more sneaky in the sense that we set a per-cpu flag on any
MMIO write and do the sync automatically in spin_unlock() :-)

Ben.

  parent reply	other threads:[~2007-08-23  7:26 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-22  4:57 wmb vs mmiowb Nick Piggin
2007-08-22 18:07 ` Linus Torvalds
2007-08-22 19:02   ` Jesse Barnes
2007-08-23  2:20     ` Nick Piggin
2007-08-23  2:57       ` Linus Torvalds
2007-08-23  3:54         ` Nick Piggin
2007-08-23 16:14           ` Linus Torvalds
2007-08-23  4:20         ` Nick Piggin
2007-08-23 16:16           ` Linus Torvalds
2007-08-23 16:27             ` Benjamin Herrenschmidt
2007-08-24  3:09               ` Nick Piggin
2007-08-28 20:56                 ` Brent Casavant
2007-08-29  0:59                   ` Nick Piggin
2007-08-29 18:53                     ` Brent Casavant
2007-08-30  3:36                       ` Nick Piggin
2007-08-30 19:42                         ` Brent Casavant
2007-09-03 20:48                           ` Nick Piggin
2007-08-24  2:59             ` Nick Piggin
2007-08-23 17:02       ` Jesse Barnes
2007-08-23  1:59   ` Nick Piggin
2007-08-23  7:27   ` Benjamin Herrenschmidt [this message]
2007-08-23 16:56     ` Jesse Barnes
2007-08-24  3:12       ` Nick Piggin
2007-08-28 21:21       ` Brent Casavant
2007-08-28 23:01         ` Peter Chubb
2007-08-23  7:25 ` Benjamin Herrenschmidt

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