On 12/21/18 12:34 PM, Paolo Bonzini wrote:
FWIW, I had missed the early version that used RCU, but lockcnt is already very RCU-like, so not using RCU is the right thing to do. The difference between lockcnt and RCU is that cleanup is done by the reader instead of a separate thread. Because we know that reader/writer concurrency is very rare for AioContext handlers, the tradeoffs favor lockcnt over RCU.
Indeed, i forgot to CC you in the first batch (get_maintainer.pl was not finding you).
Thanks for the RCU hints, i though the performance hit was due to the RCU being global to qemu.
Remy
