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Date: Tue, 5 Jan 2010 13:02:46 +0530
Message-ID: <8d6898731001042332m6b5b97b0n5515ae166f62aad2@mail.gmail.com>
Subject: Re: init_task belongs to "process 0" or "process 1"?
From: Nobin Mathew <nobin.mathew@gmail.com>
To: Shivdas Gujare <shivdas.tech@gmail.com>
Cc: linux-kernel@vger.kernel.org
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init_task is the head of doubly linked list which holds all
task_structs in the system. init_task is again the task_struct for
process 0/swapper/idle task. This process is created manually (I meant
to say not by copy_process() calls). Manually means they are static
structures defined in the code (see INIT_TASK, init_mm, init_fs etc).
There will be multiple idle task if there is more than 1 cpu core.
Idle task is the one which is scheduled if there is no other task
ready for scheduling.

Init task is process 1 which is initially a kernel thread created from
process 0 using copy_process(), then it does an execv() (/sbin/init )
or similar one to create the normal process init.

Name given to process 0 is swapper.
.comm           = "swapper"


On Mon, Jan 4, 2010 at 1:37 PM, Shivdas Gujare <shivdas.tech@gmail.com> wrote:
> Hi all,
>
> I am trying to understand the role of linux kernel "process 0" i.e. swapper.
> I am not able to understand, where it gets started? and Does
> "init_task" from arch/arm/kernel/init_task.c belongs to "swapper" or
> "init"?
> whats the purpose of "init_task"?
>
> Thanks for your help.
>
> Thanks and Regards,
> Shivdas Gujare
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