On 07/09/2021 14:31, Jason Gunthorpe wrote: > On Sun, Sep 05, 2021 at 05:36:23PM +0300, Gal Pressman wrote: > >>> I can't say if it is needed or not, just wanted to understand why you need >>> complexity in destroy_cq path. >> >> Well, as I said, I don't think the restrack protection is enough in this case as >> it isn't aware of the concurrent eq flow. >> >> I guess I can put a synchronize_irq() on destroy_cq flow to get rid of the race. > > That is a better choice that synchronize_rcu(), IIRC > > synchronize_rcu should be avoided compared to all other forms of > synchronization because it can take seconds per call to complete, and > in a reasonable verbs app this means potentially minutes to close the > verbs FD and destroy many CQs. Got it, will use synchronize_irq, thanks.
