Messages in this thread | | | Date | Thu, 29 Mar 2018 18:49:25 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH 8/8] fs/aio: Use rcu_work instead of explicit rcu and work item |
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On 03/27, Tejun Heo wrote: > > On Tue, Mar 27, 2018 at 04:28:48PM +0200, Oleg Nesterov wrote: > > > flush_*work() guarantees to wait for the completion of the latest > > > instance of the work item which was visible to the caller. We can't > > > guarantee that w/o rcu_barrier(). > > > > And this is what I can't understand. > > > > So let me repeat. Could you please describe a use-case which needs flush_rcuwork() > > with rcu_barrier() ? > > So, if you skip that, flush_work() in itself won't wait for PENDING > bit at all. It'll return right away if the work item is waiting for > rcu grace period.
Still no use-case... But yes, I forgot this is needed for correctness.
OK, thanks for your patience. But fyi now I hate this interface even more, exactly because I was technically wrong in this discussion ;)
Oleg.
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