From: "H. Peter Anvin" <hpa@zytor.com>
To: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>,
akpm@linux-foundation.org, Pekka Enberg <penberg@cs.helsinki.fi>,
linux-kernel@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [cpuops cmpxchg double V2 1/4] Generic support for this_cpu_cmpxchg_double
Date: Thu, 06 Jan 2011 14:05:05 -0800 [thread overview]
Message-ID: <4D263C91.30709@zytor.com> (raw)
In-Reply-To: <20110106204525.222395863@linux.com>
On 01/06/2011 12:45 PM, Christoph Lameter wrote:
> Introduce this_cpu_cmpxchg_double. this_cpu_cmpxchg_double() allows the
> comparision between two consecutive words and replaces them if there is
> a match.
>
> bool this_cpu_cmpxchg_double(pcp1, pcp2,
> old_word1, old_word2, new_word1, new_word2)
>
> this_cpu_cmpxchg_double does not return the old value (difficult since
> there are two words) but a boolean indicating if the operation was
> successful.
>
> The first percpu variable must be double word aligned!
I really truly hate this interface. The whole notion of passing two
pointers where only one is really used, is just painful.
-hpa
next prev parent reply other threads:[~2011-01-06 22:06 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 [this message]
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
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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