Re: schedule_timeout()

From: Andrew Morton (
Date: Tue Aug 20 2002 - 13:40:20 EST

Lahti Oy wrote:
> Why does schedule_timeout() take a signed long as an argument and then check
> for possible negative values? Wouldn't it be better to just take an unsigned
> long as argument, thus eliminating all dumb checks in the code?

Because someone may do:

        schedule_timeout(when_i_want_to_wake - jiffies);

and if the current time happens to be _after_ when_i_want_to_wake,
we want schedule_timeout to cope with that and do the right thing.

> Another issue I found concerns setting current task state to TASK_RUNNING
> after calling schedule_timeout(). This seems to be done in many parts of the
> kernel, though Kernel-API documentations found from seem
> to claim that task state is guaranteed to be TASK_RUNNING after
> schedule_timeout() returns. Is the documentation faulty or does the kernel
> have obsoleted code?

The documentation is correct.
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This archive was generated by hypermail 2b29 : Fri Aug 23 2002 - 22:00:20 EST