Re: [PATCH] Make __get_cpu_var use raw_smp_processor_id()

[David S. Miller]

From: "J.A. Magallon" <jamagallon@xxxxxxx>
Date: Thu, 23 Mar 2006 22:11:25 +0100

> --- linux-2.6.15-rc5/include/asm-generic/percpu.h.orig	2005-12-21 15:13:27.000000000 -0600
> +++ linux-2.6.15-rc5/include/asm-generic/percpu.h	2005-12-21 15:13:43.000000000 -0600
> @@ -13,7 +13,7 @@ extern unsigned long __per_cpu_offset[NR
>  
>  /* var is in discarded region: offset to particular copy we want */
>  #define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]))
> -#define __get_cpu_var(var) per_cpu(var, smp_processor_id())
> +#define __get_cpu_var(var) per_cpu(var, raw_smp_processor_id())

I'm skeptical because this has caught real bugs in the past.

Unfortunately other platforms that hard-code the per-cpu
area into a cpu register, and thus implement __get_cpu_var()
without a smp_processor_id() call, don't get the debugging
check.
-
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