From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@linux.com>
Cc: akpm@linux-foundation.org, Neil Horman <nhorman@tuxdriver.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
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: [Use cpuops V1 06/11] drivers: Replace __get_cpu_var with __this_cpu_read if not used for an address.
Date: Tue, 07 Dec 2010 15:31:40 +0100 [thread overview]
Message-ID: <4CFE454C.3010908@kernel.org> (raw)
In-Reply-To: <20101206171639.749599301@linux.com>
On 12/06/2010 06:16 PM, Christoph Lameter wrote:
> __get_cpu_var() can be replaced with this_cpu_read and will then use a single
> read instruction with implied address calculation to access the correct per cpu
> instance.
>
> However, the address of a per cpu variable passed to __this_cpu_read() cannot be
> determed (since its an implied address conversion through segment prefixes).
> Therefore apply this only to uses of __get_cpu_var where the addres of the
> variable is not used.
>
> V3->V4:
> - Move one instance of this_cpu_inc_return to a later patch
> so that this one can go in without percpu infrastructrure
> changes.
>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Signed-off-by: Christoph Lameter <cl@linux.com>
applied.
--
tejun
next prev parent reply other threads:[~2010-12-07 14:32 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-06 17:16 [Use cpuops V1 00/11] Use this_cpu_ops Christoph Lameter
2010-12-06 17:16 ` [Use cpuops V1 01/11] percpucounter: Optimize __percpu_counter_add a bit through the use of this_cpu() options Christoph Lameter
2010-12-07 13:59 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 02/11] vmstat: Optimize zone counter modifications through the use of this cpu operations Christoph Lameter
2010-12-07 14:00 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 03/11] x86: Use this_cpu_ops to optimize code Christoph Lameter
2010-12-06 17:16 ` [Use cpuops V1 04/11] x86: Use this_cpu_ops for current_cpu_data accesses Christoph Lameter
2010-12-07 14:17 ` Tejun Heo
2010-12-07 14:20 ` Tejun Heo
2010-12-07 14:46 ` Christoph Lameter
2010-12-07 14:59 ` Tejun Heo
2010-12-07 15:07 ` Christoph Lameter
2010-12-07 15:08 ` Tejun Heo
2010-12-07 16:21 ` Christoph Lameter
2010-12-08 13:16 ` [PATCH] x86: Replace uses of current_cpu_data with this_cpu ops Tejun Heo
2010-12-08 13:38 ` Eric Dumazet
2010-12-08 15:33 ` Christoph Lameter
2010-12-08 17:17 ` Eric Dumazet
2010-12-08 17:20 ` Tejun Heo
2010-12-08 17:33 ` Christoph Lameter
2010-12-08 17:57 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 05/11] core: Replace __get_cpu_var with __this_cpu_read if not used for an address Christoph Lameter
2010-12-07 14:29 ` Tejun Heo
2010-12-07 14:51 ` Christoph Lameter
2010-12-07 15:21 ` Tejun Heo
2010-12-07 15:38 ` Christoph Lameter
2010-12-08 15:24 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 06/11] drivers: " Christoph Lameter
2010-12-07 14:31 ` Tejun Heo [this message]
2010-12-06 17:16 ` [Use cpuops V1 07/11] kprobes: Use this_cpu_ops Christoph Lameter
2010-12-07 15:03 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 08/11] Fakekey: Simplify speakup_fake_key_pressed through this_cpu_ops Christoph Lameter
2010-12-07 15:07 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 09/11] Connector: Use this_cpu operations Christoph Lameter
2010-12-07 15:08 ` Tejun Heo
2010-12-07 15:36 ` Christoph Lameter
2010-12-06 17:16 ` [Use cpuops V1 10/11] fs: Use this_cpu_xx operations in buffer.c Christoph Lameter
2010-12-07 15:16 ` Tejun Heo
2010-12-06 17:16 ` [Use cpuops V1 11/11] Xen: Use this_cpu_ops Christoph Lameter
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