On Wed, Nov 27, 2013 at 07:59:13PM +0400, Kirill Tkhai wrote: > This patch touches RT group scheduling case. > > Functions inc_rt_prio_smp() and dec_rt_prio_smp() change (global) rq's > priority, > while rt_rq passed to them may be not the top-level rt_rq. This is wrong, > because > changing of priority on a child level does not guarantee that the priority is > the highest all over the rq. So, this leak makes RT balancing unusable. > > The short example: the task having the highest priority among all rq's RT > tasks > (no one other task has the same priority) are waking on a throttle rt_rq. > The rq's cpupri is set to the task's priority equivalent, but real > rq->rt.highest_prio.curr is less. > > The patch below fixes the problem. > > It looks like all version have this bug, so I CC'ed stable mailing list.
Yeah, I think this is right. cpupri stuff should indeed only be changed for the top level group. -- 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/
