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Subject: Re: [PATCH] printk: use this_cpu_{read|write} api on printk_pending
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org,
        heiko.carstens@de.ibm.com, tglx@linutronix.de, mingo@elte.hu,
        Christoph Lameter <cl@linux.com>
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Date: Fri, 26 Nov 2010 17:29:48 +0100
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On Fri, 2010-11-26 at 17:22 +0100, Eric Dumazet wrote:
> [PATCH] printk: use this_cpu_{read|write} api on printk_pending
> 
> __get_cpu_var() is a bit inefficient, lets use __this_cpu_read() and
> __this_cpu_write() to manipulate printk_pending.
> 
> printk_needs_cpu(cpu) is called only for the current cpu :
> Use faster __this_cpu_read().
> 
> remove the redondant unlikely on (cpu_is_offline(cpu)) test
> 
> # size kernel/printk.o*
>    text    data     bss     dec     hex filename
>    9942     756  263488  274186   42f0a kernel/printk.o.new
>    9990     756  263488  274234   42f3a kernel/printk.o.old


Thanks, queued!