On Mon, May 11, 2020 at 07:36:28PM +0100, Stefan Hajnoczi wrote:
> This bug was introduced in QEMU 5.0 and causes guests to slow down because
> AioHandlers are not freed when the fdmon-io_uring file descriptor monitoring
> implementation is used by the main loop thread's glib event loop. This issue
> does not apply to IOThread usage of fdmon-io_uring.
> 
> In practice few distros build with io_uring support enabled at the moment, so
> the number of affected users is likely to be small. The fix is still suitable
> for a stable release though.
> 
> https://bugs.launchpad.net/qemu/+bug/1877716
> https://bugs.launchpad.net/qemu/+bug/1873032
> 
> Stefan Hajnoczi (2):
>   aio-posix: don't duplicate fd handler deletion in
>     fdmon_io_uring_destroy()
>   aio-posix: disable fdmon-io_uring when GSource is used
> 
>  include/block/aio.h   |  3 +++
>  util/aio-posix.c      | 13 +++++++++++++
>  util/aio-win32.c      |  4 ++++
>  util/async.c          |  1 +
>  util/fdmon-io_uring.c | 13 ++++++++++---
>  5 files changed, 31 insertions(+), 3 deletions(-)

This has been merged into qemu.git/master.

Stefan