From: Nick Piggin <nickpiggin@yahoo.com.au>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: 'Christoph Lameter' <clameter@sgi.com>,
Zoltan Menyhart <Zoltan.Menyhart@bull.net>,
"Boehm, Hans" <hans.boehm@hp.com>,
"Grundler, Grant G" <grant.grundler@hp.com>,
akpm@osdl.org, linux-kernel@vger.kernel.org,
linux-ia64@vger.kernel.org
Subject: Re: Synchronizing Bit operations V2
Date: Fri, 31 Mar 2006 02:53:21 +0000 [thread overview]
Message-ID: <442C99A1.6060901@yahoo.com.au> (raw)
In-Reply-To: <200603310244.k2V2iQg28203@unix-os.sc.intel.com>
Chen, Kenneth W wrote:
> Christoph Lameter wrote on Thursday, March 30, 2006 6:38 PM
>
>>>>Neither one is correct because there will always be one combination of
>>>>clear_bit with these macros that does not generate the required memory
>>>>barrier.
>>>
>>>Can you give an example? Which combination?
>>
>>For Option(1)
>>
>>smp_mb__before_clear_bit()
>>clear_bit(...)(
>
>
> Sorry, you totally lost me. It could me I'm extremely slow today. For
> option (1), on ia64, clear_bit has release semantic already. The comb
> of __before_clear_bit + clear_bit provides the required ordering. Did
> I miss something? By the way, we are talking about detail implementation
> on one specific architecture. Not some generic concept that clear_bit
> has no ordering stuff in there.
>
The memory ordering that above combination should produce is a
Linux style smp_mb before the clear_bit. Not a release.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
WARNING: multiple messages have this Message-ID (diff)
From: Nick Piggin <nickpiggin@yahoo.com.au>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: "'Christoph Lameter'" <clameter@sgi.com>,
Zoltan Menyhart <Zoltan.Menyhart@bull.net>,
"Boehm, Hans" <hans.boehm@hp.com>,
"Grundler, Grant G" <grant.grundler@hp.com>,
akpm@osdl.org, linux-kernel@vger.kernel.org,
linux-ia64@vger.kernel.org
Subject: Re: Synchronizing Bit operations V2
Date: Fri, 31 Mar 2006 12:53:21 +1000 [thread overview]
Message-ID: <442C99A1.6060901@yahoo.com.au> (raw)
In-Reply-To: <200603310244.k2V2iQg28203@unix-os.sc.intel.com>
Chen, Kenneth W wrote:
> Christoph Lameter wrote on Thursday, March 30, 2006 6:38 PM
>
>>>>Neither one is correct because there will always be one combination of
>>>>clear_bit with these macros that does not generate the required memory
>>>>barrier.
>>>
>>>Can you give an example? Which combination?
>>
>>For Option(1)
>>
>>smp_mb__before_clear_bit()
>>clear_bit(...)(
>
>
> Sorry, you totally lost me. It could me I'm extremely slow today. For
> option (1), on ia64, clear_bit has release semantic already. The comb
> of __before_clear_bit + clear_bit provides the required ordering. Did
> I miss something? By the way, we are talking about detail implementation
> on one specific architecture. Not some generic concept that clear_bit
> has no ordering stuff in there.
>
The memory ordering that above combination should produce is a
Linux style smp_mb before the clear_bit. Not a release.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2006-03-31 2:53 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-30 21:02 Bit operations with the ability to specify a synchronization mode Christoph Lameter
2006-03-30 21:02 ` Christoph Lameter
2006-03-31 0:18 ` Synchronizing Bit operations V2 Christoph Lameter
2006-03-31 0:18 ` Christoph Lameter
2006-03-31 0:39 ` Chen, Kenneth W
2006-03-31 0:39 ` Chen, Kenneth W
2006-03-31 0:42 ` Christoph Lameter
2006-03-31 0:42 ` Christoph Lameter
2006-03-31 0:45 ` Christoph Lameter
2006-03-31 0:45 ` Christoph Lameter
2006-03-31 0:42 ` David Mosberger-Tang
2006-03-31 0:42 ` David Mosberger-Tang
2006-03-31 0:49 ` Christoph Lameter
2006-03-31 0:49 ` Christoph Lameter
2006-03-31 6:10 ` Chris Wright
2006-03-31 6:10 ` Chris Wright
2006-03-31 0:44 ` Nick Piggin
2006-03-31 0:44 ` Nick Piggin
2006-03-31 3:28 ` Christoph Lameter
2006-03-31 3:28 ` Christoph Lameter
2006-03-31 4:12 ` Nick Piggin
2006-03-31 4:12 ` Nick Piggin
2006-03-31 17:43 ` Christoph Lameter
2006-03-31 17:43 ` Christoph Lameter
2006-04-01 2:56 ` Nick Piggin
2006-04-01 2:56 ` Nick Piggin
2006-03-31 0:50 ` Chen, Kenneth W
2006-03-31 0:50 ` Chen, Kenneth W
2006-03-31 0:51 ` Christoph Lameter
2006-03-31 0:51 ` Christoph Lameter
2006-03-31 0:53 ` Chen, Kenneth W
2006-03-31 0:53 ` Chen, Kenneth W
2006-03-31 0:55 ` Christoph Lameter
2006-03-31 0:55 ` Christoph Lameter
2006-03-31 0:56 ` Luck, Tony
2006-03-31 0:56 ` Luck, Tony
2006-03-31 0:58 ` Christoph Lameter
2006-03-31 0:58 ` Christoph Lameter
2006-04-02 7:59 ` Russell King
2006-04-02 7:59 ` Russell King
2006-03-31 0:59 ` Chen, Kenneth W
2006-03-31 0:59 ` Chen, Kenneth W
2006-03-31 1:09 ` Christoph Lameter
2006-03-31 1:09 ` Christoph Lameter
2006-03-31 1:04 ` Chen, Kenneth W
2006-03-31 1:04 ` Chen, Kenneth W
2006-03-31 1:13 ` Christoph Lameter
2006-03-31 1:13 ` Christoph Lameter
2006-03-31 1:13 ` Chen, Kenneth W
2006-03-31 1:13 ` Chen, Kenneth W
2006-03-31 1:29 ` Chen, Kenneth W
2006-03-31 1:29 ` Chen, Kenneth W
2006-03-31 1:37 ` Christoph Lameter
2006-03-31 1:37 ` Christoph Lameter
2006-03-31 1:33 ` linux
2006-03-31 1:33 ` linux
2006-03-31 1:40 ` Christoph Lameter
2006-03-31 1:40 ` Christoph Lameter
2006-03-31 2:35 ` Chen, Kenneth W
2006-03-31 2:35 ` Chen, Kenneth W
2006-03-31 2:37 ` Christoph Lameter
2006-03-31 2:37 ` Christoph Lameter
2006-03-31 2:45 ` Chen, Kenneth W
2006-03-31 2:45 ` Chen, Kenneth W
2006-03-31 2:53 ` Nick Piggin [this message]
2006-03-31 2:53 ` Nick Piggin
2006-03-31 3:01 ` Christoph Lameter
2006-03-31 3:01 ` Christoph Lameter
2006-03-31 2:51 ` Chen, Kenneth W
2006-03-31 2:51 ` Chen, Kenneth W
2006-03-31 2:55 ` Christoph Lameter
2006-03-31 2:55 ` Christoph Lameter
2006-03-31 3:02 ` Chen, Kenneth W
2006-03-31 3:02 ` Chen, Kenneth W
2006-03-31 3:08 ` Christoph Lameter
2006-03-31 3:08 ` Christoph Lameter
2006-03-31 3:10 ` Chen, Kenneth W
2006-03-31 3:10 ` Chen, Kenneth W
2006-03-31 3:12 ` Christoph Lameter
2006-03-31 3:12 ` Christoph Lameter
2006-03-31 3:11 ` Chen, Kenneth W
2006-03-31 3:11 ` Chen, Kenneth W
2006-03-31 3:14 ` Chen, Kenneth W
2006-03-31 3:14 ` Chen, Kenneth W
2006-03-31 3:20 ` Christoph Lameter
2006-03-31 3:20 ` Christoph Lameter
2006-03-31 3:17 ` Chen, Kenneth W
2006-03-31 3:17 ` Chen, Kenneth W
2006-03-31 3:23 ` Chen, Kenneth W
2006-03-31 3:23 ` Chen, Kenneth W
2006-03-31 3:37 ` Chen, Kenneth W
2006-03-31 3:37 ` Chen, Kenneth W
2006-03-31 6:15 ` Chen, Kenneth W
2006-03-31 6:15 ` Chen, Kenneth W
2006-03-31 7:34 ` Nick Piggin
2006-03-31 7:34 ` Nick Piggin
2006-03-31 13:28 ` Andi Kleen
2006-03-31 13:28 ` Andi Kleen
2006-03-31 16:22 ` Hans Boehm
2006-03-31 16:22 ` Hans Boehm
2006-03-31 16:37 ` Andi Kleen
2006-03-31 16:37 ` Andi Kleen
2006-03-31 17:46 ` Christoph Lameter
2006-03-31 17:46 ` Christoph Lameter
2006-03-31 17:45 ` Christoph Lameter
2006-03-31 17:45 ` Christoph Lameter
2006-03-31 17:48 ` Andi Kleen
2006-03-31 17:48 ` Andi Kleen
2006-03-31 17:56 ` Christoph Lameter
2006-03-31 17:56 ` Christoph Lameter
2006-04-02 7:54 ` Russell King
2006-04-02 7:54 ` Russell King
2006-03-31 18:57 ` Chen, Kenneth W
2006-03-31 18:57 ` Chen, Kenneth W
2006-03-31 19:41 ` Chen, Kenneth W
2006-03-31 19:41 ` Chen, Kenneth W
2006-03-31 21:15 ` Christoph Lameter
2006-03-31 21:15 ` Christoph Lameter
2006-03-31 21:24 ` Chen, Kenneth W
2006-03-31 21:24 ` Chen, Kenneth W
2006-03-31 21:28 ` Christoph Lameter
2006-03-31 21:28 ` Christoph Lameter
2006-04-01 2:16 ` Nick Piggin
2006-04-01 2:16 ` Nick Piggin
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