Re: [PATCH v2] sched: Fix broken setscheduler()

From: Thomas Gleixner
Date: Mon Mar 10 2014 - 17:18:59 EST


On Mon, 10 Mar 2014, Steven Rostedt wrote:

> On Thu, 6 Mar 2014 21:43:50 +0100 (CET)
> Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> > > Reading what the commit is suppose to do, I realize that the p->prio
> > > can't be set if the task is boosted with a higher prio, but the
> > > p->normal_prio still needs to be set regardless, otherwise, when the
> > > task is deboosted, it wont get the new priority.
> >
> > Indeed.
>
> Is this an Acked-by?
>
> Peter, can you pull this patch please, it is still broken in tip/master.

Lemme look at it tomorrow again with an awake brain. This seems to be
some forward porting hickup which needs a closer look. Just look at
the 3.10-rt version of this:

@@ -3825,20 +3826,25 @@ static struct task_struct *find_process_by_pid(pid_t pid)
return pid ? find_task_by_vpid(pid) : current;
}

-/* Actually do priority change: must hold rq lock. */
-static void
-__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
+static void __setscheduler_params(struct task_struct *p, int policy, int prio)
{
p->policy = policy;
p->rt_priority = prio;
p->normal_prio = normal_prio(p);
+ set_load_weight(p);
+}

That code has changed significantly probably due to the EDF merge. We
need to figure out whether there is more damage due to that.

Thanks,

tglx
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