Re: Information about move_tasks return

[Randy.Dunlap]

Darren Hart wrote:
> On Mon, 2004-11-22 at 08:16 -0400, Cícero wrote:
>
> > hi
> >
> > I am looking for the result of the function  move_task in
> >
> > kernel/sched.c , I have observed that it returns an int value and as I
> > print it with printk.
> >
> > I have created a int variable 'results_move_task' which capture the result of
> >
> > move_task and I print it with printk("%d",results_move_task); I
> > observed that it often returns the value '1' and sometimes it returns
> > '2' or more. Is it really correct?
>
>
> /*
>  * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq,
>  * as part of a balancing operation within "domain". Returns the number of
>  * tasks moved.
>  *
>  * Called with both runqueues locked.
>  */
> static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
>                       unsigned long max_nr_move, struct sched_domain *sd,
>                       enum idle_type idle)
> {
> ...
>
>
> So as the "documentation" states, it returns the number of tasks
> actually moved.  For instance, The balancing code may request 4 tasks be
> moved, but for various reasons, only 2 were actually moved to other
> CPUs, move_tasks() would return 2.

and there are a few cases/places where the move target count
is limited to only 1.

--
~Randy
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