A problem with percpu variable cpu_number

[Tao Jiang]

Hi:

I've asked the question on kernelnewbies, no replies.
So forward it here.
Thank you.


---------- Forwarded message ----------
From: tao jiang <jiangtao.jit@xxxxxxxxx>
Date: 2012/2/16
Subject: A problem with percpu variable cpu_number
To: kernelnewbies <kernelnewbies@xxxxxxxxxxxxxxxxx>


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()


Thank you.

---------------
jiangtao
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