Hi Peter, On Wed, Nov 12, 2014 at 04:39:06PM +0100, Peter Zijlstra wrote: >On Wed, Nov 12, 2014 at 03:08:44PM +0000, Juri Lelli wrote: >> > @@ -1185,8 +1223,9 @@ static int find_later_rq(struct task_struct *task) >> > * We have to consider system topology and task affinity >> > * first, then we can look for a suitable cpu. >> > */ >> > - cpumask_copy(later_mask, task_rq(task)->rd->span); >> > - cpumask_and(later_mask, later_mask, cpu_active_mask); >> > + cpumask_copy(later_mask, cpu_active_mask); >> > + if (likely(task_rq(task)->online)) >> > + cpumask_and(later_mask, later_mask, task_rq(task)->rd->span); >> >> So, here you consider the span only when the task_rq is online, >> but there might be others cpus still online belonging to the same >> rd->span. And you have to consider them when migrating. Actually, >> migration must still be restricted to the online cpus of task's >> original rd->span, or I fear you can break clustered scheduling. > >Ah, good point that, we must somehow find the right root domain to >'restore' the task to. Now I'm not entirely sure we still have this. >Lemme ponder that.
Any idea is a great appreciated. :-) Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
