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SubjectRe: [RFC PATCH 1/9] arm: avoid using on_each_cpu hard coded ret value
On Tue, Jan 03, 2012 at 04:19:05PM +0200, Gilad Ben-Yossef wrote:
> on_each_cpu always returns a hard coded return code of zero.
>
> Removing all tests based on this return value saves run time
> cycles for compares and code bloat for branches.
>
> Cc: Michal Nazarewicz <mina86@mina86.com>
> CC: Will Deacon <will.deacon@arm.com>
> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Ingo Molnar <mingo@elte.hu>
> CC: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> CC: Russell King <linux@arm.linux.org.uk>
> CC: Grant Likely <grant.likely@secretlab.ca>
> CC: Rob Herring <rob.herring@calxeda.com>
> CC: linux-arm-kernel@lists.infradead.org
> CC: devicetree-discuss@lists.ozlabs.org
> ---
> arch/arm/kernel/perf_event.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
> index 88b0941..bfd58d8 100644
> --- a/arch/arm/kernel/perf_event.c
> +++ b/arch/arm/kernel/perf_event.c
> @@ -617,7 +617,7 @@ static int __init
> cpu_pmu_reset(void)
> {
> if (cpu_pmu && cpu_pmu->reset)
> - return on_each_cpu(cpu_pmu->reset, NULL, 1);
> + on_each_cpu(cpu_pmu->reset, NULL, 1);
> return 0;
> }
> arch_initcall(cpu_pmu_reset);
This patch results in no binary change for my test build with SMP=n and
it saves one instruction on SMP=y.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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