From: Cong Wang <xiyou.wangcong@gmail.com>
To: Tao Jiang <jiangtao.jit@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: A problem with percpu variable cpu_number
Date: Sun, 19 Feb 2012 23:21:23 +0800 [thread overview]
Message-ID: <4F411373.50304@gmail.com> (raw)
In-Reply-To: <CAOe6JY2W8H2FMbMUsUp=72gH6y_SXPvjwZ0fqOwXWUdknr=7yQ@mail.gmail.com>
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.
next prev parent reply other threads:[~2012-02-19 15:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-16 11:09 A problem with percpu variable cpu_number tao jiang
2012-02-19 12:20 ` Tao Jiang
2012-02-19 15:21 ` Cong Wang [this message]
2012-02-20 11:04 ` Tao Jiang
2012-02-20 15:11 ` Cong Wang
2012-02-21 12:41 ` Tao Jiang
2012-02-21 14:29 ` Cong Wang
2012-02-21 17:58 ` Brian Gerst
2012-02-22 11:13 ` Tao Jiang
2012-02-22 13:21 ` Hillf Danton
2012-02-23 14:29 ` Tao Jiang
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