Messages in this thread | | | Date | Mon, 9 Jan 2006 15:01:42 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending() |
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On Sun, Jan 08, 2006 at 10:19:24PM +0300, Oleg Nesterov wrote: > ->donelist becomes != NULL only in rcu_process_callbacks(). > > rcu_process_callbacks() always calls rcu_do_batch() when > ->donelist != NULL. > > rcu_do_batch() schedules rcu_process_callbacks() again if > ->donelist was not flushed entirely. > > So ->donelist != NULL means that rcu_tasklet is either > TASKLET_STATE_SCHED or TASKLET_STATE_RUN, we don't need to > check it in __rcu_pending().
Do I smell a bug wrt CPU Hotplug here? Basically, I see that we do a rcu_move_batch of ->curlist and ->nxtlist of the dead CPU. Why not ->donelist? If we have to do a rcu_move_batch of ->donelist also, then perhaps the ->donelist != NULL check is required in rcu_pending? This is considering that the RCU tasklet of the dead CPU is killed (rather than moved over to a different CPU).
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Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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