Re: [PATCH 2/5] rcu: don't check ->donelist in __rcu_pending()

From: Srivatsa Vaddagiri
Date: Mon Jan 09 2006 - 08:41:37 EST


On Mon, Jan 09, 2006 at 05:51:08PM +0300, Oleg Nesterov wrote:
> Srivatsa Vaddagiri wrote:
> > If we have to do a rcu_move_batch of ->donelist also,
> > then perhaps the ->donelist != NULL check is required in
> > rcu_pending?
>
> rcu_move_batch() always adds entries to the ->nxttail, so I think
> this patch is correct.

Hmm ..adding entries on dead cpu's ->donelist to ->nxtlist of some other CPU
doesnt make sense (it re-triggers graceperiods for all those callbacks which is
not needed). Maybe rcu_move_batch should take that into account and instead add
to ->donelist of current CPU which is processing the CPU_DEAD callback.

In which case, ->donelist != NULL check is still reqd in rcu_pending ?


--


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
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