Re: [RFC][PATCH 08/17] sched: Drop the rq argument to sched_class::select_task_rq()

[Yong Zhang]

On Mon, Jan 3, 2011 at 7:16 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> On Wed, 2010-12-29 at 22:31 +0800, Yong Zhang wrote:
>> On Fri, Dec 24, 2010 at 01:23:46PM +0100, Peter Zijlstra wrote:
>> > In preparation of calling select_task_rq() without rq->lock held, drop
>> > the dependency on the rq argument.
>> >
>> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>> > ---
>> > @@ -3416,27 +3409,22 @@ void sched_exec(void)
>> > Â{
>> > Â Â struct task_struct *p = current;
>> > Â Â unsigned long flags;
>> > - Â struct rq *rq;
>> > Â Â int dest_cpu;
>> >
>> > - Â rq = task_rq_lock(p, &flags);
>> > - Â dest_cpu = p->sched_class->select_task_rq(rq, p, SD_BALANCE_EXEC, 0);
>> > + Â raw_spin_lock_irqsave(&p->pi_lock, flags);
>>
>> Seems this should go to patch 07/17 ;)
>
> Ah, the reason its here is that this patch removes the rq argument and
> thus we no longer need rq->lock. So this part relies on the property
> introduced by patch 7.

What I mean is we could firstly add pi_lock in patch 7 and then remove
the rq argument in this patch. :)

Thanks,
Yong

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