Re: where is the task_struct set up for a new task?

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David Whysong wrote:
>
> Can someone point me in the right direction? I'm looking through the code
> for a place where (for example) p->priority is set for a new task.

For 386?

As soon as the kernel starts, right in arch/i386/kernel/head.S, the
stack pointer is initialised to point 8k beyond the start of 'union
task_union', which is defined in init_task.c

So at this point in time, the stack looks like this:

SP -> ---------------- 8k
        | |
        | |
          ...
        |--------------|
        | task_union |
current ---------------- 0k

So the initial kernel thread's task_struct is defined by the INIT_TASK
macro in include/linux/sched.h. The declaration in init_task.c does the
RAM initialisation. union task_union provides the stack for the kernel
during booting.

The initial kernel task is started at the end of
init/main.c:start_kernel(), still using this initial task_struct.

>From this point on, all new tasks/threads inherit a copy of their
parent's task_struct in kernel/fork.c:do_fork():

            *p = *current;
 

-- 
-akpm-
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