Messages in this thread | | | Date | Tue, 13 Aug 2019 08:57:07 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH V5 0/9] Fixes for vhost metadata acceleration |
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On Tue, Aug 13, 2019 at 04:31:07PM +0800, Jason Wang wrote:
> What kind of issues do you see? Spinlock is to synchronize GUP with MMU > notifier in this series.
A GUP that can't sleep can't pagefault which makes it a really weird pattern
> Btw, back to the original question. May I know why synchronize_rcu() is not > suitable? Consider:
We already went over this. You'd need to determine it doesn't somehow deadlock the mm on reclaim paths. Maybe it is OK, the rcq_gq_wq is marked WQ_MEM_RECLAIM at least..
I also think Michael was concerned about the latency spikes a long RCU delay would cause.
Jason
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