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SubjectRe: Inconsistency in changing the state of task ??
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On Tue, 2003-03-04 at 03:36, prash_t@softhome.net wrote:

> while browsing through fs/select.c file of 2.4.19, I came across two
> DIFFERENT ways of changing the state of the current task in do_select():
>
> set_current_state = TASK_INTERRUPTIBLE;
> AND current->state = TASK_RUNNING;
>
> I am curious to know if the second line of code doesn't cause any problem in
> SMP systems. I also see the same situation in do_poll().

You normally want to use set_current_state(), which is a nice
abstraction and safe for SMP.

Sometimes it is safe to use __set_current_state(), which does not
provide a memory barrier.

The above open-coded line can be changed to
__set_current_state(TASK_RUNNING).

Robert Love

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