Il 28/11/2013 10:49, Avi Kivity ha scritto: > Linux is safe, it does interrupt migration from within the interrupt > handler. If you do that before the device-specific EOI, you won't get > another interrupt until programming the MSI is complete. > > Is virtio safe? IIRC it can post multiple interrupts without guest acks. > > Using call_rcu() is a better solution than srcu IMO. Less code changes, > consistently faster.
call_rcu() has the problem of rate limiting, too. It wasn't such a great idea, I think. The QRCU I linked would work great latency-wise (it has roughly the same latency of an rwsem but readers are lock-free). However, the locked operations in the read path would hurt because of cache misses, so it's not good either. Paolo
