On Tue, Feb 18, 2020 at 06:27:08PM +0000, Stefan Hajnoczi wrote:
> The first rcu_read_lock/unlock() is expensive.  Nested calls are cheap.
> 
> This optimization increases IOPS from 73k to 162k with a Linux guest
> that has 2 virtio-blk,num-queues=1 and 99 virtio-blk,num-queues=32
> devices.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  util/aio-posix.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan