Re: A problem with percpu variable cpu_number

From: Cong Wang
Date: Sun Feb 19 2012 - 10:21:44 EST


On 02/19/2012 08:20 PM, Tao Jiang wrote:
Hi :

At the beginning of start_kernel() -- init/main.c
boot_cpu_init() is called

and in boot_cpu_init() will call smp_processor_id()
it's a macro
and it will be expanded as (percpu_read(cpu_number)) and so on

but i noticed that it's before setup_per_cpu_areas() in start_kernel()
is that mean the percpu areas hadn't be initialized yet
but why smp_processor_id() could be called before setup_per_cpu_areas()

It doesn't matter, as the percpu var 'cpu_number' is defined statically: DECLARE_PER_CPU(int, cpu_number);.

Thanks.
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