From: Avi Kivity <avi@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: 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>,
Tejun Heo <tj@kernel.org>
Subject: Re: [rfc: cpuops adv V1 3/8] x86: this_cpu_cmpxchg and this_cpu_cmpxchg_double operations
Date: Mon, 06 Dec 2010 19:14:45 +0200 [thread overview]
Message-ID: <4CFD1A05.3020900@redhat.com> (raw)
In-Reply-To: <20101202215400.609058574@linux.com>
On 12/02/2010 11:53 PM, Christoph Lameter wrote:
> Provide support as far as the hardware capabilities of the x86 cpus
> allow.
>
>
>
> +/*
> + * Beware: xchg on x86 has an implied lock prefix. There will be the cost of
> + * full lock semantics even though they are not needed.
> + */
Perhaps we can use cmpxchg instead of xchg to avoid this? costs one more
instruction but may be worth it.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-12-06 17:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-02 21:53 [rfc: cpuops adv V1 0/8] Cmpxchg and xchg support for cpu ops Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 1/8] percpu: generic this_cpu_cmpxchg() and this_cpu_cmpxchg_double support Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 2/8] --- include/linux/percpu.h | 31 +++---------------------------- 1 file changed, 3 insertions(+), 28 deletions(-) Christoph Lameter
2010-12-02 22:06 ` [rfc: cpuops adv V1 2/8] Fallback to atomic xchg, cmpxchg Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 3/8] x86: this_cpu_cmpxchg and this_cpu_cmpxchg_double operations Christoph Lameter
2010-12-06 17:14 ` Avi Kivity [this message]
2010-12-06 17:35 ` Christoph Lameter
2010-12-07 9:31 ` Avi Kivity
2010-12-02 21:53 ` [rfc: cpuops adv V1 4/8] irq_work: Use per cpu atomics instead of regular atomics Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 5/8] vmstat: User per cpu atomics to avoid interrupt disable / enable Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 6/8] Lockless (and preemptless) fastpaths for slub Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 7/8] slub: Add PageSlubPartial Christoph Lameter
2010-12-02 21:53 ` [rfc: cpuops adv V1 8/8] slub: [RFC] Partially lockless freepath slowpath Christoph Lameter
2010-12-04 19:29 ` [rfc: cpuops adv V1 0/8] Cmpxchg and xchg support for cpu ops Pekka Enberg
2010-12-04 19:31 ` Tejun Heo
2010-12-06 15:52 ` Christoph Lameter
2010-12-06 15:51 ` Christoph Lameter
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