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 07:27:15 +0000 [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.
WARNING: multiple messages have this Message-ID (diff)
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.
next prev parent reply other threads:[~2007-08-23 7:27 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-22 4:57 wmb vs mmiowb Nick Piggin
2007-08-22 4:57 ` Nick Piggin
2007-08-22 18:07 ` Linus Torvalds
2007-08-22 18:07 ` Linus Torvalds
2007-08-22 19:02 ` Jesse Barnes
2007-08-22 19:02 ` Jesse Barnes
2007-08-23 2:20 ` Nick Piggin
2007-08-23 2:20 ` Nick Piggin
2007-08-23 2:57 ` Linus Torvalds
2007-08-23 2:57 ` Linus Torvalds
2007-08-23 3:54 ` Nick Piggin
2007-08-23 3:54 ` Nick Piggin
2007-08-23 16:14 ` Linus Torvalds
2007-08-23 16:14 ` Linus Torvalds
2007-08-23 4:20 ` Nick Piggin
2007-08-23 4:20 ` Nick Piggin
2007-08-23 16:16 ` Linus Torvalds
2007-08-23 16:16 ` Linus Torvalds
2007-08-23 16:27 ` Benjamin Herrenschmidt
2007-08-23 16:27 ` Benjamin Herrenschmidt
2007-08-24 3:09 ` Nick Piggin
2007-08-24 3:09 ` Nick Piggin
2007-08-28 20:56 ` Brent Casavant
2007-08-28 20:56 ` Brent Casavant
2007-08-29 0:59 ` Nick Piggin
2007-08-29 0:59 ` Nick Piggin
2007-08-29 18:53 ` Brent Casavant
2007-08-29 18:53 ` Brent Casavant
2007-08-30 3:36 ` Nick Piggin
2007-08-30 3:36 ` Nick Piggin
2007-08-30 19:42 ` Brent Casavant
2007-08-30 19:42 ` Brent Casavant
2007-09-03 20:48 ` Nick Piggin
2007-09-03 20:48 ` Nick Piggin
2007-08-24 2:59 ` Nick Piggin
2007-08-24 2:59 ` Nick Piggin
2007-08-23 17:02 ` Jesse Barnes
2007-08-23 17:02 ` Jesse Barnes
2007-08-23 1:59 ` Nick Piggin
2007-08-23 1:59 ` Nick Piggin
2007-08-23 7:27 ` Benjamin Herrenschmidt [this message]
2007-08-23 7:27 ` Benjamin Herrenschmidt
2007-08-23 16:56 ` Jesse Barnes
2007-08-23 16:56 ` Jesse Barnes
2007-08-24 3:12 ` Nick Piggin
2007-08-24 3:12 ` Nick Piggin
2007-08-28 21:21 ` Brent Casavant
2007-08-28 21:21 ` Brent Casavant
2007-08-28 23:01 ` Peter Chubb
2007-08-28 23:01 ` Peter Chubb
2007-08-23 7:25 ` Benjamin Herrenschmidt
2007-08-23 7:25 ` Benjamin Herrenschmidt
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