Hi Ingo/Peter,
I am trying to understand the complex scheduler code and just found
something incorrect (maybe i am not reading it well):
File: kernel/sched/fair.c
static void
prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
{
if (!p->se.on_rq)
return;
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
* this runqueue and our priority is higher than the current's
*/
if (rq->curr == p) {
if (p->prio > oldprio)
resched_task(rq->curr);
} else
check_preempt_curr(rq, p, 0);
}
Comment says that we must mark the task to be rescheduled, if we
are currently running and our priority has decreased. But in code we
are checking (p->prio > oldprio). i.e. reschedule if we were currently
running and our priority increased.
Sorry if i am wrong :(
--
viresh
On 11/07/2012 03:49 PM, Viresh Kumar wrote:
Hi, Viresh
> Hi Ingo/Peter,
>
> I am trying to understand the complex scheduler code and just found
> something incorrect (maybe i am not reading it well):
>
> File: kernel/sched/fair.c
>
> static void
> prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
> {
> if (!p->se.on_rq)
> return;
>
> /*
> * Reschedule if we are currently running on this runqueue and
> * our priority decreased, or if we are not currently running on
> * this runqueue and our priority is higher than the current's
> */
> if (rq->curr == p) {
> if (p->prio > oldprio)
> resched_task(rq->curr);
> } else
> check_preempt_curr(rq, p, 0);
> }
>
>
> Comment says that we must mark the task to be rescheduled, if we
> are currently running and our priority has decreased. But in code we
> are checking (p->prio > oldprio). i.e. reschedule if we were currently
> running and our priority increased.
It's the user nice value I suppose, so it should be reversed when we are
talking about weight.
Regards,
Michael Wang
>
> Sorry if i am wrong :(
>
> --
> viresh
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On 7 November 2012 13:26, Michael Wang <[email protected]> wrote:
> It's the user nice value I suppose, so it should be reversed when we are
> talking about weight.
Ahh.. I knew it .. How can i miss it.
Sorry for the noise :(
--
viresh