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SubjectRe: [RFC][PATCH v2] sched/rt: Use IPI to trigger RT task push migration instead of pulling
On Tue, 24 Feb 2015 13:39:46 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> @@ -1775,6 +1946,15 @@ static int pull_rt_task(struct rq *this_
> */
> smp_rmb();
>
> + /* Use local just in case a feature is switched in the middle of this */
> + if ((use_ipi = sched_feat(RT_PUSH_IPI))) {
> + /* Make sure the update to pending is visible here. */
> + smp_rmb();

While porting this to the -rt kernel, I noticed that this rmb is
unneeded. It's already called above for a different reason :-p

-- Steve

> +
> + /* If a push ipi is out, then we must do the old method */
> + push_pending = READ_ONCE(this_rq->rt.push_csd_pending);
> + }
> +
> for_each_cpu(cpu, this_rq->rd->rto_mask) {
> if (this_cpu == cpu)
> continue;


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