On Fri, Aug 09, 2013 at 05:31:27PM +0800, Lai Jiangshan wrote: > On 08/09/2013 04:40 AM, Paul E. McKenney wrote: > > One problem here -- it may take quite some time for a set_need_resched() > > to take effect. This is especially a problem for RCU priority boosting, > > but can also needlessly delay preemptible-RCU grace periods because > > local_irq_restore() and friends don't check the TIF_NEED_RESCHED bit. > > > The final effect of deboosting(rt_mutex_unlock()) is also accomplished > via set_need_resched()/set_tsk_need_resched(). > set_need_resched() is enough for RCU priority boosting issue here.
But there's a huge difference between the boosting and deboosting side of things. rcu_read_unlock_special() starts the boost, the deboosting only matters if/when you reschedule. -- 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/
