From: "H. Peter Anvin" <hpa@zytor.com>
To: Tejun Heo <tj@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
Christoph Lameter <cl@linux.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [cpuops cmpxchg double V2 1/4] Generic support for this_cpu_cmpxchg_double
Date: Fri, 21 Jan 2011 08:30:41 -0800 [thread overview]
Message-ID: <c661a1e2-4e08-4e6b-b2c8-93e231be981f@email.android.com> (raw)
In-Reply-To: <20110121154831.GE2832@htj.dyndns.org>
There is a technical argument: any noninline version will have actual code overhead.
"Tejun Heo" <tj@kernel.org> wrote:
>Hello, Peter.
>
>On Fri, Jan 21, 2011 at 07:31:55AM -0800, H. Peter Anvin wrote:
>> I really object to passing two pointers where one of them has to be a
>> fixed offset to the other. That really doesn't make any sense.
>
>Yeah, I hear you, but it really comes down to which ugliness disgusts
>one the most. That, unfortunately, is inherently very subjective when
>there's no significantly better choice.
>
>For me, the double parameter thing at least seems to have the
>advantages of being able to verify the two intended memory locations
>to be used actually are together and looking ugly reflecting its true
>nature.
>
>The inherent ugliness stems from the fact that we don't have the
>built-in data type to properly deal with this. Array of length two
>might be better fit, but I can see as many downsides with that too.
>
>So, if anyone can give something clearly better for technical reasons,
>I'll be more than happy to take it, but as it currently stands, it
>seems we'll have to choose one among uglies and not everyone would be
>happy about the choice. :-(
>
>Thanks.
>
>--
>tejun
--
Sent from my mobile phone. Please pardon any lack of formatting.
next prev parent reply other threads:[~2011-01-21 16:32 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-06 20:45 [cpuops cmpxchg double V2 0/4] this_cpu_cmpxchg_double support Christoph Lameter
2011-01-06 20:45 ` [cpuops cmpxchg double V2 1/4] Generic support for this_cpu_cmpxchg_double Christoph Lameter
2011-01-06 21:08 ` Mathieu Desnoyers
2011-01-06 21:43 ` Christoph Lameter
2011-01-06 22:05 ` H. Peter Anvin
2011-01-07 15:15 ` Christoph Lameter
2011-01-07 18:04 ` Mathieu Desnoyers
2011-01-07 18:41 ` Christoph Lameter
2011-01-08 17:24 ` Tejun Heo
2011-01-09 8:33 ` Pekka Enberg
2011-01-21 7:31 ` Pekka Enberg
2011-01-21 9:26 ` Tejun Heo
2011-01-21 15:31 ` H. Peter Anvin
2011-01-21 15:48 ` Tejun Heo
2011-01-21 16:30 ` H. Peter Anvin [this message]
2011-01-21 16:34 ` Tejun Heo
2011-01-21 16:54 ` Mathieu Desnoyers
2011-01-21 17:07 ` Christoph Lameter
2011-01-21 17:50 ` Mathieu Desnoyers
2011-01-21 18:06 ` Christoph Lameter
2011-01-21 18:37 ` Mathieu Desnoyers
2011-01-21 17:08 ` Tejun Heo
2011-01-21 17:13 ` H. Peter Anvin
2011-01-21 17:19 ` Tejun Heo
2011-01-24 6:01 ` H. Peter Anvin
2011-02-25 13:09 ` Pekka Enberg
2011-02-25 13:19 ` Tejun Heo
2011-02-25 16:26 ` Christoph Lameter
2011-02-25 16:37 ` Tejun Heo
2011-02-25 16:43 ` Christoph Lameter
2011-02-25 16:38 ` Eric Dumazet
2011-02-25 16:45 ` Christoph Lameter
2011-01-21 17:24 ` Christoph Lameter
2011-01-21 17:42 ` Mathieu Desnoyers
2011-01-21 17:50 ` Christoph Lameter
2011-01-21 18:10 ` Mathieu Desnoyers
2011-01-21 18:42 ` Christoph Lameter
2011-01-21 18:31 ` H. Peter Anvin
2011-01-21 18:46 ` Christoph Lameter
2011-01-21 19:32 ` Mathieu Desnoyers
2011-01-23 18:00 ` H. Peter Anvin
2011-01-06 20:45 ` [cpuops cmpxchg double V2 2/4] x86: this_cpu_cmpxchg_double() support Christoph Lameter
2011-01-06 20:45 ` [cpuops cmpxchg double V2 3/4] slub: Get rid of slab_free_hook_irq() Christoph Lameter
2011-01-06 20:45 ` [cpuops cmpxchg double V2 4/4] Lockless (and preemptless) fastpaths for slub Christoph Lameter
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