Re: [PATCH 2/4] ia64: allocate percpu area for cpu0 like percpuareas for other cpus
From: Christoph Lameter
Date: Tue Sep 22 2009 - 19:18:24 EST
On Tue, 22 Sep 2009, Tejun Heo wrote:
>
> +#ifdef CONFIG_SMP
> + . = ALIGN(PERCPU_PAGE_SIZE);
> + __cpu0_per_cpu = .;
__per_cpu_start?
> + . = . + PERCPU_PAGE_SIZE; /* cpu0 per-cpu space */
> +#endif
This is a statically sized per cpu area that is used by __get_cpu_var()
Data is access via a cpu specific memory mapping. How does this work when
the area grows beyond PERCPU_PAGE_SIZE? As far as I can see: It seems
that __get_cpu_var would then cause a memory fault?
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